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Proposed Rule

Endangered and Threatened Wildlife and Plants: Proposed Threatened Status for Southern Distinct Population Segment of North American Green Sturgeon


Proposed Rule; Request For Comments.


We, the NMFS, have completed an update of anEndangered Species Act (ESA) status review for the North American greensturgeon (Acipenser medirostris; hereafter “greensturgeon”). After reviewing new and updated information on thestatus of green sturgeon and considering whether green sturgeon is indanger of extinction throughout all or a significant portion of its range,or is likely to become endangered within the foreseeable future throughoutall or a significant portion of its range, we confirm our earlierdetermination that the species is comprised of two distinct populationsegments (DPSs) that qualify as species under the ESA, the Northern andSouthern DPSs. We reaffirm our earlier determination that the Northern DPSdoes not warrant listing as threatened or endangered at this time, and wewill maintain the DPS on the Species of Concern List due to remaininguncertainties about its status and threats. We revise our previous“not warranted” finding for the Southern DPS and propose tolist it as threatened. This revision is based on: new information showingthat the majority of spawning adults are concentrated into one spawningriver (i.e., Sacramento River), thus increasing the risk of extirpation dueto catastrophic events; threats that have remained severe since the laststatus review and have not been adequately addressed by conservationmeasures currently in place; fishery-independent data exhibiting a negativetrend in juvenile green sturgeon abundance; and new information showingevidence of lost spawning habitat in the upper Sacramento and FeatherRivers. We will reevaluate the status of the Northern DPS in 5 years. Ifthe proposed listing is finalized, a recovery plan will be prepared andimplemented for the Southern DPS. Protective regulations under ESA section4(d) and critical habitat will be proposed in a subsequent Federal Register notice.


Table of Contents Back to Top

DATES: Back to Top

Comments on this proposal must be received by July 5, 2005. A public hearing will be held promptly if any person sorequests by May 23, 2005. Notice of the location and time of any such hearingwill be published in the Federal Register not less than 15days before the hearing is held.

ADDRESSES: Back to Top

You may submit comments by any of thefollowing methods:

  • E-Mail:
  • Federal e-Rulemaking Portal: Follow the instructions forsubmitting comments.
  • Mail: Submit written comments to Chief, Protected ResourcesDivision, Southwest Region, National Marine Fisheries Service, 501 WestOcean Blvd., Suite 4200, Long Beach, CA, 90802-4213.

The updated green sturgeon status review and other reference materialsregarding this determination can be obtained via the Internet at: or by submitting a request to theAssistant Regional Administrator, Protected Resources Division, SouthwestRegion, NMFS, 501 West Ocean Blvd., Suite 4200, Long Beach, CA90802-4213, or the Assistant Regional Administrator, ProtectedResources Division, Northwest Region, NMFS, 1201 NE Lloyd Avenue, Suite1100, Portland, OR 97232.


Melissa Neuman, NMFS,Southwest Region (562) 980-4115; Scott Rumsey, NMFS, Northwest Region(503) 872-2791; or Lisa Manning, NMFS, Office of Protected Resources(301) 713-1401.


Background Back to Top

On June 12, 2001, we received a petition from the EnvironmentalProtection Information Center, Center for Biological Diversity, andWaterKeepers Northern California requesting that we list the green sturgeonas threatened or endangered under the ESA and that critical habitat bedesignated for the species concurrently with any listing determination. OnDecember 14, 2001, we provided notice of our determination that thepetition presented substantial scientific information indicating that thepetitioned action may be warranted and requested information to assist witha status review to determine if green sturgeon warranted listing under theESA (66 FR 64793). To assist in the status review, we formed a BiologicalReview Team (BRT) comprised of scientists from our Northwest and SouthwestFisheries Science Centers and from the United States Geological Survey(USGS). We also requested technical information and comments from Stateand Tribal co-managers in California, Oregon, and Washington, as well asfrom scientists and individuals having research or management expertisepertaining to green sturgeon from California and the Pacific Northwest.The BRT considered the best available scientific and commercialinformation, including information presented in the petition and inresponse to our request for information concerning the status of andefforts being made to protect the species (66 FR 64793; December 14, 2001).The BRT presented its findings in a final status review report for NorthAmerican green sturgeon (Adams et al., 2002). Under the ESA,a listing determination may address a species, subspecies, or a DPS of anyvertebrate species which interbreeds when mature (16 U.S.C. 1532(16)). OnFebruary 7, 1996, the U.S. Fish and Wildlife Service (FWS) and NMFS adopteda policy describing what constitutes a DPS of a taxonomic species (61 FR4722). The joint DPS policy identified two elements that must beconsidered when making DPS determinations: (1) The discreteness of thepopulation segment in relation to the remainder of the species (orsubspecies) to which it belongs; and (2) the significance of the populationsegment to the remainder of the species (or subspecies) to which itbelongs. After conducting the status review, we determined that greensturgeon is comprised of two DPSs that qualify as species under the ESA:(1) a northern DPS consisting of populations in coastal watershedsnorthward of and including the Eel River (“Northern DPS”); and(2) a southern DPS consisting of coastal and Central Valley populationssouth of the Eel River, with the only known population in the SacramentoRiver (“Southern DPS”).

The BRT considered the following information in order to assess riskfactors for each green sturgeon DPS: (1) abundance trends from fisheriesdata; (2) the effects of fishing bycatch; (3) the possible loss of spawninghabitat in rivers where spawning is reported to have occurred historically,but apparently no longer does; (4) concentration of spawning in the Klamathand Sacramento River systems; (5) lack of adequate population abundancedata; (6) potentially lethal water temperatures and adverse effects ofcontaminants; (7) entrainment (defined here as loss of green sturgeon dueto water diversion) by water projects; and (8) adverse effects ofnon-native species. Based on the 2002 risk assessment, we determined onJanuary 23, 2003, that neither DPS warranted listing as threatened orendangered (68 FR 4433). Uncertainties in the structure and status of bothDPSs led us to add them to the Species of Concern List (formerly thecandidate species list; 69 FR 19975; April 15, 2004). Along with thefinding, we announced that we would reevaluate the status of green sturgeonin 5 years.

On April 7, 2003, the Environmental Protection Information Center (andother Plaintiffs) challenged our “not warranted” finding forgreen sturgeon. The U.S. District Court for the Northern District ofCalifornia issued an order on March 2, 2004, which set aside our “notwarranted” finding and remanded the matter to us for redeterminationof whether green sturgeon is in danger of extinction throughout all or asignificant portion of its range, or is likely to become endangered withinthe foreseeable future throughout all or a significant portion of itsrange. The U.S. District Court's March 2004 remand was issued because theCourt was not satisfied with our examination of whether purported lostspawning habitat constituted a significant portion of either DPS' range.We reestablished the BRT in the early summer of 2004 and added a new memberfrom USGS who possessed considerable knowledge of green sturgeon. The BRTwas asked to consider recent scientific and commercial informationavailable regarding the biological status of green sturgeon and to assistus in assessing the viability of the species throughout all or asignificant portion of its range. We published a notice on June 18, 2004,soliciting information from the public to assist us in updating our statusreview and making a new listing determination (69 FR 34135).

In addition to the information solicited during the first status review,we solicited any new information beyond that considered in the 2002 greensturgeon status review or the January 2003 1-year “notwarranted” finding on the following topics for the Northern andSouthern DPSs of green sturgeon: (1) new genetic, morphological,physiological, or ecological information relevant to DPS identification;(2) current or historic information documenting the geographic extent(e.g., area, river mile distance) and magnitude (e.g., abundance ofspawning females, reproductive output) of spawning in particular riversystems (e.g., Fraser River, Umpqua River, South Fork Trinity River, EelRiver, Feather River, and San Joaquin River); (3) information documentingthe current geographic extent and magnitude of spawning in areas other thanwhere it is known to presently occur (i.e., areas other than the SacramentoRiver, Klamath River and Rogue River); (4) the legitimacy of referencesused to support information regarding current or historic spawning in thesystems mentioned above in (2) and (3), particularly citations by Houston(1988) for the Fraser River; Lauman et al. (1972) and theOregon Department of Fish and Wildlife (ODFW) (2002) for the Umpqua River;Moyle et al. (1992) and references therein for the South ForkTrinity River; Puckett (1976), Moyle et al. (1992) andreferences therein for the Eel River; Wang (1986) and FWS (1995) for theFeather River; and Moyle et al. (1992) and references thereinfor the San Joaquin River; (5) historic, current or future factors that maybe responsible for the reported loss of spawning habitat and associatedspawning populations; and (6) fishery-dependent and -independent abundancedata for analysis of population trends.

The public comment period closed on August 17, 2004. The BRT convenedto draft an updated status review in November 2004.

On January 27, 2005, we distributed the updated status review toco-managers (i.e., States of Washington, Oregon and California, Yurok andHoopa Tribes, FWS, and the California Bay-Delta Program) for review. Thefinal updated status review for green sturgeon was completed by the BRT onFebruary 22, 2005, and submitted to NMFS Regional Offices for furtherconsideration prior to the publication of this notice.

Biology and Life History of Green Sturgeon Back to Top

A thorough account of green sturgeon biology and life history may befound in the previous 1-year finding (68 FR 4433; January 23, 2003)and the updated status review (Adams et al., 2005), which areincorporated here by reference. The following is a summary of thatinformation.

Adult Distribution and Feeding

The green sturgeon is the most widely distributed member of the sturgeonfamily Acipenseridae. Like all sturgeon species it is anadromous, but itis also the most marine-oriented of the sturgeon species. Green sturgeonare known to range in nearshore marine waters from Mexico to the Bering Seaand are commonly observed in bays and estuaries along the western coast ofNorth America, with particularly large concentrations entering the ColumbiaRiver estuary, Willapa Bay, and Grays Harbor during the late summer (Moyle et al., 1992). The reasons for these concentrations areunclear, but do not appear to be related to spawning or feeding(Beamesderfer, 2000).

Little is known about adult green sturgeon feeding. Adults in theSacramento-San Joaquin Delta are reported to feed on benthic invertebratesincluding shrimp, mollusks, amphipods, and even small fish (Moyle et al., 1992). One hundred and twenty-one green sturgeonstomach samples from the Columbia River gillnet fishery were empty with theexception of one fish, while all white sturgeon stomachs contained digestedmaterial (ODFW 2002).


Adult green sturgeon are thought to spawn every 3 to 5 years (Tracy,1990), but new information suggests that spawning could occur as frequentlyas every 2 years (Lindley and Moser, pers. comm., 2004). Adults typicallymigrate into fresh water beginning in late February (Moyle etal., 1995); spawning occurs from March July, with peak activity fromApril June (Moyle et al., 1995). Confirmed spawningpopulations in North America are in the Rogue (Erickson etal., 2001, Rien et al., 2001), Klamath, and SacramentoRivers (Moyle et al., 1992; CDFG, 2002). Green sturgeonfemales produce 60,000 - 140,000 eggs (Moyle et al., 1992),and they are the largest eggs (diameter 4.34mm) of any sturgeon species(Cech et al., 2000). Spawning occurs in deep turbulent rivermainstems. Klamath and Rogue River populations appear to spawn within 100miles (161 km) of the ocean, while the Sacramento spawning run may travelover 200 miles (322 km). Specific spawning habitat preferences areunclear, but eggs likely are broadcast over large cobble where they settleinto the cracks (Moyle et al., 1995). Optimum flow andtemperature requirements for spawning and incubation are unclear, butspawning success in most sturgeons is related to these factors (Dettlaff etal.,1993). Temperatures above 68 F (20°C) were lethal to embryos inlaboratory experiments (Cech et al., 2000).

Early Life History and Maturation

Green sturgeon larvae first feed at 10 days post hatch and grow quicklyreaching a length of 66mm and a weight of 1.8 g in 3 weeks of exogenousfeeding. Metamorphosis to the juvenile stage is complete at 45 days.Juveniles continue to grow rapidly, reaching 300mm in 1 year and over 600mmwithin 2 3 years for the Klamath River (Nakamoto et al.,1995). Juveniles spend from 1 4 years in fresh and estuarine waters anddisperse into salt water at lengths of 300-750mm. The little that isknown regarding juvenile green sturgeon feeding habits comes from a studyconducted in the Sacramento-San Joaquin Delta, where juveniles fed onopossum shrimp and amphipods (Radtke, 1966).

Green sturgeon disperse widely in the ocean after their out-migrationfrom freshwater (Moyle et al., 1992). Tagged green sturgeonfrom the Sacramento and Columbia Rivers are primarily captured to the northin coastal and estuarine waters, with some fish tagged in the ColumbiaRiver being recaptured as far north as British Columbia (WDFW, 2002a).While there is some bias associated with recovery of tagged fish throughcommercial fishing, the pattern of a northern migration is supported by thelarge concentration of green sturgeon in the Columbia River estuary,Willapa Bay, and Grays Harbor, which peaks in August. These fish tend tobe immature; however, mature fish and at least one ripe fish have beenfound in the lower Columbia River (WDFW, 2002a). Genetic evidence suggeststhat Columbia River green sturgeon are a mixture of fish from at least theSacramento, Klamath, and Rogue Rivers (Israel et al., 2002).Mature males range from 139 199cm in fork length (FL) and 15 to 30 years ofage (VanEenennaam, 2002). Mature females range from 157 223cm FL and 17 to40 years of age. Maximum ages of adult green sturgeon are likely to rangefrom 60-70 years (Moyle, 2002).

Summary of New Information Back to Top

Consideration as a “Species” Under the ESA

The ESA defines species as “any subspecies of fish or wildlife orplants, and any distinct population segment of any species of vertebratefish or wildlife that interbreeds when mature” 16 U.S.C. 1532(16).This definition allows for the recognition of DPSs at levels belowtaxonomically recognized species or subspecies. On February 7, 1996, theFWS and NMFS published a joint policy to clarify the phrase “distinctpopulation segment” for the purposes of listing, delisting andreclassifying species under the ESA (61 FR 4722). This policy identifiestwo criteria that must be met for a population segment to be considered aDPS under the ESA: (1) The discreteness of the population segment inrelation to the remainder of the species or subspecies to which it belongs;and (2) the significance of the population segment to the species orsubspecies to which it belongs.

New genetic information in combination with the tendency of sturgeon toexhibit high spawning site fidelity confirms the conclusions drawn duringthe previous 1-year “not warranted” finding (68 FR 4433;January 29, 2003) that the northern and southern populations of greensturgeon are “discrete” and “significant” asdefined in the DPS policy. (For a complete discussion of the discretenessand significance of the U.S. population of green sturgeon see 68 FR at4437).

Genetic Information

Updated analyses of green sturgeon genetic structure were made availablefrom University of California - Davis (J. Israel and B. May, pers. comm.,2004). These results incorporated a greater number of samples includingnew adult samples from the Umpqua River, new juvenile samples from theSacramento River, and an increase in microsatellite DNA loci to nine overthe six reported in the previous status review and discussed in Israel et. al. (2004). Green sturgeon samples demonstrate a strongdivision between a grouping of the Rogue, Klamath, and Umpqua Rivers versusa grouping of the Sacramento and Columbia Rivers and San Pablo Bay samples.The northern group included mixed stock green sturgeon samples from theUmpqua River as well as single stock samples from the Rogue and KlamathRivers and the southern group included mixed stock samples from theColumbia River, samples from San Pablo Bay that may be either mixed orsingle stock, and single stock samples from the Sacramento River.

Oceanic Distribution and Behavior

New oceanic distribution and behavior information came from pop-offarchival tags (7 fish), Oregon trawl logbook analysis, and acoustic tags(168 fish). These data indicated that green sturgeon generally makenorthward migrations, to points as far north as northwest Vancouver Island,Canada, upon returning to the ocean. During oceanic migrations, archivaltagged fish occupied depths of 40-70 m and remained exclusivelyinside the 110 m contour. These results are confirmed by Oregon trawllogbook records (Erickson and Hightower, 2004). Fish marked in spawningareas (Rogue and Klamath Rivers and San Pablo Bay) and in mixed stock areas(Columbia River and Willapa Bay) with acoustic tags in 2002, 2003, and 2004sustained migrations of 100 km per day. Several fish tagged in 2002returned to the Rogue River in 2004, suggesting a minimal spawningperiodicity of 2 years if it is assumed that these fish were ripe andreturning to the River to spawn (S. Lindley and M. Moser, pers. comm.,2004).

Freshwater Distribution Information

We requested new historic and/or current information for particularriver systems where historic and current spawning status is uncertain(e.g., Fraser River, Umpqua River, South Fork Trinity River, Eel River,Feather River, and San Joaquin River; 69 FR 34135). New information wasreceived for the Chehalis, Umpqua, Rogue, and Eel Rivers within theNorthern DPS and the Sacramento, Feather, and San Joaquin Rivers within theSouthern DPS.

Northern DPS

Washington Department of Fish and Wildlife (WDFW) investigated theChehalis River as potential green sturgeon habitat, and while it appears topossess suitable habitat features for green and white sturgeon spawning,there has not been evidence of spawning occurring in this basin (WDFW,2004). Data summarized from catch record cards suggest that a few greensturgeon were caught in sport fisheries as far upriver as 60 kilometersduring July 2002, March 2003, and December 2003, but these may bemisidentifications of white sturgeon, which are much more common within thebasin. Sport anglers have reported small green sturgeon in Grays Harbor;however, these fish were most likely of a post-migratory size and thereforewere not fish rearing in the estuary. Green and white sturgeon eggs andlarvae have not been observed in the Chehalis River or Grays Harbor.

There are two confirmed records of green sturgeon captured above tidalinfluence in the Umpqua River (T. Rien, pers. comm., 2004). In July 2000,two juvenile green sturgeon (each approximately 10-cm long) wereregurgitated from two smallmouth bass caught at river kilometer (rkm) 134on the Umpqua River. The ODFW interviewed the local angling guide, and theone available regurgitated fish was positively identified as a greensturgeon. The other regurgitated sturgeon was not available to examine.In April 1979, a 1.8 m green sturgeon was caught at rkm 164 on the UmpquaRiver. A picture of the fish was published in the Roseburg News Review(May 3, 1979) and it was visually identified as a green sturgeon by ODFW.ODFW has sampled the Umpqua River in 2002, 2003, and 2004 using gill nets,beach seines, snorkeling, and underwater video, and their sampling effortsdid not capture any green sturgeon above tidal influence in the UmpquaRiver.

A putative green juvenile sturgeon was captured at Big Butte Creek (rkm254) near Lost Creek Dam on the Rogue River (R. Reisenbichler, pers. comm.,2004). This is unusual because it is very high in the system and above twomajor dams with fish ladders (Savage Rapids and Gold Ray) and severalsmaller dams.

Adult green sturgeon were sighted on the mainstem Eel River near FortSeward, California (rkm 101) during snorkel surveys in 1995 and 1996 (S.Downie, pers. comm., 2004). Three sturgeon were sighted each year at aplace locally known as “The Sturgeon Hole.” Two juvenile greensturgeon were captured in the Eel River estuary in 1994 by trawl (S.Cannata, pers. comm., 2004). The first one was 282mm FL and the second was510mm. This is in addition to the previously reported capture of 26juvenile green sturgeon near Fort Seward in 1967 and 1968 (Pluckett,1976).

Southern DPS

Recent habitat evaluations conducted in the upper Sacramento and FeatherRivers for salmonid recovery planning suggest that significant potentialgreen sturgeon spawning habitat was made inaccessible or altered by dams(historical habitat characteristics, temperature, and geology summarized inLindley et al., 2004). This spawning habitat may haveextended up into the three major branches of the Sacramento River, theLittle Sacramento River, the Pit River system, and the McCloud River.

Green and white sturgeon adults have been observed periodically in smallnumbers in the Feather River (Beamesderfer et al., 2004).There are at least two confirmed records of adult green sturgeon in 2004.There are no records of larval or juvenile sturgeon of either species, evenprior to the 1960's when Oroville Dam was built. There are reports thatgreen sturgeon may reproduce in the Feather River during high flow years(CDFG, 2002), but these are not specific and are unconfirmed.

Small fisheries for sturgeon occur in spring on the San Joaquin Riverbetween Mossdale and the Merced River (Kohlhorst, 1976). Though sturgeonare known to migrate into the San Joaquin River, no efforts have been madeto document sturgeon reproduction (FWS, 1995). In addition, data are notregularly collected at diversions on the San Joaquin River, and whensturgeon have been collected, species differentiation rarely occurred.Information exists through interviews with biologists, wardens, and anglersregarding the presence and potential spawning of white sturgeon on the SanJoaquin River (FWS, 1995). Two juvenile white sturgeon caught atWoodbridge on the Mokelumne River (rkm 63) in 2003 are the firstconfirmation of white sturgeon reproduction in the San Joaquin River system(Beamesderfer et al., 2004). Though no green sturgeon haveever been documented in the San Joaquin River upstream of the Delta or inthe Stanislaus, Tuolumne, and Merced Rivers (CDFG, 2002; Beamesderfer et al., 2004), the San Joaquin River and its tributaries havebeen heavily modified in ways that reduce suitability for sturgeon sincethe 1940s, so the lack of contemporary information cannot be consideredevidence of historical green sturgeon absence. Moreover, species with asimilar dependence on historic deep cool waters of the San Joaquin forspawning (i.e., spring-run Chinook salmon; Yoshiyama et al.,2001; and white sturgeon, FWS, 1995) are either extirpated or nearly so onthe San Joaquin River, indicating that a once self-sustaining greensturgeon population on the San Joaquin River may have been possible.

Catch Information

The coastwide bycatch of green sturgeon continues to be reduced overtime as noted in the previous status review (Adams et al., 2002). Based onupdated and corrected bycatch numbers, green sturgeon take has been reducedfrom a high of 9,065 in 1986 to 862 in 2001, the last year in the previousstatus review, to 512 in 2003. The greatest reductions in bycatch (directand indirect) were for the commercial fisheries in the Northern DPS,specifically the Columbia River, Willapa Bay, and Grays Harbor. Thisreduction has occurred due to regulatory changes summarized in Adams et al. (2002), Appendix 1 Table 2. Yurok and Hoopa tribalgreen sturgeon fisheries have remained constant, with relatively constanteffort, and together account for 59 percent of the coastwide green sturgeoncatch in 2003.

Historic Spawning Status

Information presented in the first status review (Adams etal., 2002) and new information presented here regarding the historicand current spawning status of green sturgeon were analyzed.

Conclusions from New Information Back to Top

In earlier technical memos and Federal Register publications (66 FR 64793, December 14, 2001; 68 FR 4433, January 23,2003), we reported the loss of green sturgeon spawning habitat in theUmpqua, Fraser, South Fork Trinity, Eel (Northern DPS), Upper Sacramento,Feather, and possibly San Joaquin Rivers (Southern DPS) based oninformation presented in the petition. These claims prompted us to reportthat green sturgeon experienced a significant reduction in spawning area.New analysis of existing information and the submission of new informationto us in August 2004 (69 FR 34135) leads us to revise these earlierjudgments in the following ways.

Northern DPS Back to Top

There is no evidence of historic or current spawning in the Fraser orChehalis Rivers (D. Lane, pers. comm., 2004; WDFW, 2004). Based on thelack of data, we cannot conclude that there has been a loss of spawninghabitat over time in these systems.

Known historic and current spawning, based primarily on the presence ofjuvenile green sturgeon, occurs in the Umpqua, Rogue, Klamath and TrinityRivers, and, therefore, we conclude that populations have not beenextirpated from these systems (T. Rein, pers. comm., 2004; Erickson et al., 2002; Moyle, 2002; Sheiff et al., 2001).We are uncertain as to whether spawning habitat has been lost in the UmpquaRiver. A significant reduction in spawning habitat is not likely to haveoccurred in the Rogue River because there are no impassable barriers alonggreen sturgeon migration routes. Although the Klamath River has undergonehuman alteration, data suggest that the geographic extent of spawning inthe system has not been reduced over time. A paucity of data for theTrinity River limits our ability to comment on the magnitude of loss ofspawning habitat in this system.

There is evidence to suggest that green sturgeon spawned in the SouthFork Trinity River and continue to spawn there to some degree, based on thepresence of adults in freshwater areas above tidal influence (CDFG, 1978;Moyle et al., 1992). We suspect that spawning habitat stillexists in this system, but have no evidence to comment on whether spawninghabitat has been reduced over time.

The Eel River is the only system in the Northern DPS where the status ofspawning since historic times is believed to have changed. Spawning isknown to have occurred in the past based on the presence of juveniles(Plunkett, 1976), but recently, only adults have been present in the River(S. Downie, pers. comm., 2004) and one juvenile, whose natal stream originis uncertain, was collected in the estuary. Despite Moyle etal.'s (2002) claim that green sturgeon have been extirpated from theEel River, we determined that our ability to make a conclusion regardingextirpation is limited by: (1) low sampling effort in recent times (seeStatus of Green Sturgeon DPSs: Northern DPS); and (2) our inability todetermine how much spawning habitat or reproductive potential may have beenlost.

Southern DPS Back to Top

Known historic and current spawning, based on the presence of juvenilegreen sturgeon, occurs in the Sacramento River (Adams et al.,2002). We have indirect evidence, based on habitat assessments of Chinooksalmon, that the geographic extent of spawning has been reduced due toimpassable barriers (the Keswick and Shasta dams) in the upper SacramentoRiver. We have not been able to quantify the reduction of habitat to date,and are uncertain how reduction in spawning habitat has affected thepopulation's viability.

Spawning is suspected to have occurred in the Feather River due to thepresence of adults in the system (CDFG, 2002). Although there is noevidence of spawning in the past or now, the continued presence of adultsin the system suggests that green sturgeon are trying to migrate intopresumed spawning areas now blocked by the Oroville Dam. Therefore, weconclude that spawning habitat may have been lost in the Feather River, butwe were not able to determine how much habitat or reproductive potentialwas lost.

There is no evidence of historic or current spawning in the San JoaquinRiver (Beamesderfer, 2004; Adams et al., 2002; CDFG, 2002).While we cannot make any conclusions regarding loss of spawning habitatover time in the San Joaquin River, indirect evidence from a variety ofsources (Moyle, 2002; Lindley et al., 2004; L. Hess, pers.comm., 2004) suggests that both adult and juvenile green sturgeon may havebeen present in this system in the past. If spawning did occur in the SanJoaquin River in the past, there may have been a reduction in spawninghabitat again due to reasons mentioned above for the Sacramento and FeatherRivers.

Summary of Factors Affecting the Species Back to Top

Section 4 of the ESA (16 U.S.C. 1533) and regulations promulgated toimplement the listing provisions of the ESA (50 CFR part 424) set forth theprocedures for adding species to the Federal list of threatened andendangered species. Section 4 requires that listing determinations bebased solely on the best scientific and commercial data available, withoutconsideration of possible economic or other impacts of such determinations.A species may be determined to be endangered or threatened due to one ormore of the five factors described in section 4(a)(1) of the ESA. We mustdetermine if either DPS of green sturgeon is endangered or threatenedbecause of any one or a combination of the following factors: (1) thepresent or threatened destruction, modification, or curtailment of itshabitat or range; (2) overutilization for commercial, recreational,scientific, or educational purposes; (3) disease or predation; (4)inadequacy of existing regulatory mechanisms; or (5) other natural orhuman-made factors affecting its continued existence.

Species-wide Factors Back to Top

Ocean and estuarine bycatch of green sturgeon in the white sturgeon andsalmonid fisheries was considered a species-wide factor for decline sinceits impact could not be apportioned to one DPS or the other. Current totalcatch of green sturgeon has been reduced to 6 percent of its 1986 highvalue of 9,065 fish; this does not, however, necessarily represent areduction in green sturgeon abundance. The recent reduction is due tonewly imposed fishing regulations in Oregon and Washington. Commercialfisheries targeting sturgeon have not been allowed in the Columbia River orWillapa Bay since 2001, and recreational fishing remains negligible (WDFW,2004). Yurok and Hoopa tribal catch has remained relatively constantduring the entire time series. The reduction in catch through protective management measures represents a reduction in risk to the Northern DPS.CDFG (2002) estimated an average fishing mortality of 2.2 percent for greensturgeon based on tag return data in the Sacramento-San Joaquin Estuary.The impact of this fishing mortality rate is unknown.

A summary of DPS-specific factors for decline is presented below (Tables1 and 2). These factors were only considered for those river systems withknown or suspected historical or current spawning activity.

Northern DPS Factors Back to Top

The potential factors for decline in the Northern DPS are reduced flows,changed flow regimes, increased temperatures, and reduced oxygenconcentrations, principally in the Klamath-Trinity and Eel River systems(Table 1). The impact of these factors is uncertain. This DPS also hasthe only major in-river fishery for green sturgeon (Yurok and Hoopa tribalfisheries in the Klamath-Trinity River system), the effects of which areuncertain, but catch data show no obvious signs of decline. As mentionedin the previous section, species-wide reduction in bycatch fishingmortality through protective management measures reduces the threat ofoverfishing in the Northern DPS. No risks due to disease, predation, orinadequacy of existing regulatory mechanisms were identified. The NorthernDPS has two known major spawning populations (e.g., the Klamath-TrinityRiver system and the Rogue River) that are not close to one anothergeographically, thus spreading risks of extinction over more than onespawning area. Spawning also appears to occur infrequently in the UmpquaRiver. This gives the Northern DPS some additional protection.

Southern DPS Factors Back to Top

The principal factor for decline for this DPS comes from the reductionof green sturgeon spawning area to a limited area of the Sacramento River(Table 2). Keswick Dam provides an impassible barrier blocking greensturgeon access to what were likely historic spawning grounds upstream(FWS, 1995). A substantial amount of habitat in the Feather River aboveOroville Dam also was lost, and threats to green sturgeon on the FeatherRiver are similar to those faced in the Sacramento River (NMFS, 2004). TheBRT concluded that a viable spawning population of green sturgeon no longerexists in the Feather River and was likely lost due to the habitat blockageas a result of Oroville Dam and from thermal barriers associated with theThermalito Afterbay Facility (Table 2). Any observations of adult greensturgeon likely represent individuals that were stranded as a result ofthese barriers.

Potential adult migration barriers to green sturgeon include the RedBluff Diversion Dam (RBDD), Sacramento Deep Water Ship Channel locks,Fremont Weir, Sutter Bypass, and the Delta Cross Channel Gates on theSacramento River, and Shanghai Bench and Sunset Pumps on the Feather River.The threat of screened and unscreened agricultural, municipal, andindustrial water diversions in the Sacramento River and Delta to greensturgeon are largely unknown as juvenile sturgeon are often not identified,and current California Department of Fish and Game (CDFG) and NMFS screencriteria do not address sturgeon. Based on the temporal occurrence ofjuvenile green sturgeon and the high density of water diversion structuresalong rearing and migration routes, we find the potential threat of thesediversions to be serious and in need of study (Table 2 NMFS, 2005).

CDFG (1992) and FWS (1995) found a strong correlation between mean dailyfreshwater outflow (April to July) and white sturgeon year class strengthin the Sacramento-San Joaquin Estuary (these studies primarily involve themore abundant white sturgeon; however, the threats to green sturgeon arethought to be similar), indicating that insufficient flow rates are likelyto pose a significant threat to green sturgeon (Table 2). This associationof year class strength with outflow is also found in other anadromousfishes inhabiting the Estuary, such as striped bass, Chinook salmon,American shad, and longfin smelt (Stevens and Miller, 1983). MeanApril-May flow rates of 566 cubic meters per second appear to be theminimum required for the production of good year class strength based onapproximately 20 years of sturgeon salvage data at the Skinner FishFacility (CDFG, 2002). According to this criterion, low flow ratesoccurred slightly more than 50 percent of the time during the yearsspanning 1968-1987 (CDFG, 2002). The FWS (1995) used water yeartypes, based on an index developed for the Sacramento Basin (CaliforniaDepartment of Water Resources, 2004), to suggest that low flow conditionsoccurred 53 percent of the time during the years spanning 1944-2004.It is postulated that low flow rates could dampen survival by hampering thedispersal of larvae to areas of greater food availability, hampering thedispersal of larvae to all available habitat, delaying the transportationof larvae downstream of water diversions in the Delta, or decreasingnutrient supply to the nursery, thus stifling productivity (CDFG, 1992).There are no current indications that flow rates will increase over time.

High temperatures no longer seem to be the problem that they once werewith the installation of the Shasta Dam temperature control device in 1997,although Shasta Dam has a limited storage capacity and cold water reservescould be depleted in long droughts (Table 2). Temperatures at RBDD havenot been higher than 16° C since 1995 (California Data Exchange Center)and are within the green sturgeon egg and larvae optimum for growth andsurvival of 15° to 19° C (Mayfield and Cech, 2004). However, greensturgeon reproduction before 1995 may well have been adversely affected bytemperature and these earlier high temperatures may have caused populationreductions that would still affect the overall population size andage-structure (Table 2). Water temperatures on Feather River downstream ofthe Thermalito Afterbay outlet are considerably higher than temperatures inthe low-flow channel (FWS, 1995). It is likely that high watertemperatures (greater than 17.2° C) may deleteriously affect sturgeonegg and larval development, especially for late-spawning fish in drierwater years (FWS, 1995). CDFG (2002) also indicated water temperatures maybe inadequate for spawning and egg incubation in the Feather River duringmany years as the result of releases of warmed water from ThermalitoAfterbay. CDFG believed this may be one reason neither green nor whitesturgeon are found in the river in low-flow years. It is not expected thatwater temperatures will become more favorable in the near future (CDFG,2002) and thus elevated water temperature continues to be a threat.

Sturgeon have high vulnerability to fisheries, and the trophy status oflarge white sturgeon makes these fishes a high priority for enforcement toprotect against poaching (Table 2; CDFG, 2002). Green sturgeon are caughtincidentally in these white sturgeon fisheries.

Non-native species are an ongoing problem in the Sacramento-San JoaquinRiver and Delta systems (Table 2; CDFG, 2002). One risk for green sturgeonassociated with the introduction of non-native species involves thereplacement of relatively uncontaminated food items with those that may becontaminated. For example, the non-native overbite clam, Potamocorbula amurensis, introduced in 1988, has become the mostcommon food of white sturgeon and was found in the only green sturgeonexamined thus far (CDFG, 2002). The overbite clam is known tobioaccumulate selenium, a toxic metal (CDFG, 2002; Linville et al., 2004).Green sturgeon may also experience predation by introduced speciesincluding striped bass.

Contamination of the Sacramento River increased substantially in themid-1970s when application of rice pesticides increased (FWS, 1995).Estimated toxic concentrations for the Sacramento River during1970-1988 may have deleteriously affected striped bass larvae(Bailey, 1994). White sturgeon may also accumulate PCBs and selenium(White et al., 1989). While green sturgeon spend more timein the marine environment than white sturgeon and, therefore, may have lessexposure, the BRT concluded that some degree of risk from contaminantsprobably also occurs for green sturgeon (Table 2).

The previous status review (Adams et al., 2002) summarizedjuvenile entrainment and change in annual mean number over time. Juvenileentrainment is considered a type of threat imposed by water diversion(Table 2).



Status of Green Sturgeon DPS Back to Top

Northern DPS

The Fraser River in Canada currently has a catch and release fishery forsturgeon, but the number of green sturgeon captured is extremely small. Atagging study in 1992-1993 tagged 2300 sturgeon and only one was agreen sturgeon (D. Lane, pers. comm., 2004). Green sturgeon occur off theWest Coast of Vancouver Island where they are taken in the trawl fishery.These fish are thought to be from spawning areas in the United States, andthis idea is supported by the recent acoustic and pop-off archival tagging.WDFW has investigated the possibility of green sturgeon spawning in theChehalis River as it appears to provide suitable habitat features tosupport spawning. However, no evidence of spawning in this system hasoccurred to date. Currently, there is limited fishing in Grays Harbor, butno evidence of spawning has been found (WDFW, 2004).

Spawning does appear to take place in the Umpqua River, but is probablyrare. Juvenile green sturgeon were identified in the system in 2000.Spawning in the Umpqua River apparently is not common since substantialsampling efforts in 2002, 2003, and 2004 failed to find any evidence ofgreen sturgeon spawning.

The presence of green sturgeon spawning in the Rogue River has been onlyrecently discovered. The river is less manipulated and habitat seems to beof better quality than in other green sturgeon spawning rivers. Blockagesto migration of anadromous fish are likely to be upriver of the historicalextent of green sturgeon spawning habitat and, therefore, do not seem to belimiting; habitat seems to be roughly what it was historically. Otheranadromous salmonid fishes are generally doing well in the Rogue River(Weitkamp et al., 1995; Busby et al., 1996; andMyers et al., 1998).

The Klamath River has the largest green sturgeon spawning population.Spawning still occurs upstream to the historical limit of its habitat range(Ishi Pishi Falls). Out-migrant juvenile green sturgeon are captured eachyear in screw traps at Big Bar (Schieff et al., 2001). TheBRT expressed concerns over recent fish kills in the Klamath River, butreached no conclusions regarding whether or not the temperature regime inthe system played a part in this mortality event. The Yurok tribal fisherycomprises the majority of green sturgeon catch coastwide. There is no newinformation regarding abundance trends since the last status review (Adamset al., 2002). As discussed in the previous status review, the trends innumbers and size are difficult to interpret, but do not appear to indicatepopulation decline.

There are few available data regarding the status of green sturgeon inthe Trinity River system. The Hoopa Tribe has a small in-river fisherywhich takes fewer than 30 adult green sturgeon each year. Juvenileout-migrant green sturgeon are captured in most years in small numbers atWillow Creek (Schieff et al., 2001). Due to the continuedpresence of juveniles within the system, the BRT was not convinced thatgreen sturgeon were extirpated from the South Fork Trinity River by the1964 flood as suggested by Moyle (2002).

The Eel River is the southern-most known spawning area in the NorthernDPS. Moyle et al. (1992) suggested that green sturgeon wereextirpated from the Eel River following the 1964 flood. The 1955 and 1964floods delivered large amounts of sediment into the Eel River. Thesehistorical flood events, combined with land use practices, have resulted inpersisting high sediment levels. Some portion of the deep holes that greensturgeon use during spawning were filled in by the 1955 and 1964 floodevents, but the extent of sturgeon habitat loss is unknown. The BRT wasnot convinced that green sturgeon have been extirpated from the Eel River.Sightings of adults in both 1995 and 1996 and of juveniles in the estuaryin 1994 suggest that a green sturgeon population persists in the Eel River,although severely reduced from historical levels. Sampling was limitedwith adult surveys conducted only in 1995 and 1996 and estuarine surveysconducted only in 1993 and 1994.

The evaluation of extinction risk over a “significant portion ofits range” is difficult for this DPS because of the lack ofhistorical data about green sturgeon spawning areas. As explained above,in earlier technical memos and Federal Register publications(66 FR 64793, December 14, 2001; 68 FR 4433, January 23, 2003) we haddiscussed the possibility that spawning habitat in the Fraser, Umqua, SouthFork Trinity, and Eel Rivers had beenseverely reduced. However, afterreviewing both existing and new information, we have revised those earlierjudgments and now conclude that the Eel River is the only system in theNorthern DPS where the status of spawning since historic times is believedto have changed. All BRT members felt that the historic spawning area ofthe DPS had been larger than the current spawning area, but with nohistorical data describing spawning areas, there was a range of thoughtabout how much larger.

The BRT was unable to come to firm consensus on what should beconsidered “a significant portion” for this DPS, however, theygenerally agreed that “a significant portion” of the DPS'srange would include either the Klamath or Rogue Rivers, and that the SouthFork Trinity and Eel Rivers do not represent a significant portion of theDPS's range. The BRT's opinion regarding “significant portion of itsrange” is supported by drawing analogies from salmonid habitat useand estimated abundance in the Klamath, Rogue, South Fork Trinity and EelRivers (Lindley et al., 2004). Salmonid spawning habitat ismore extensive and estimated population abundance is higher in the Klamathand Rogue Rivers than in the South Fork Trinity and Eel Rivers, and weexpect that green sturgeon habitat requirements and population size arecorrelated with those of salmonids, both historically and today. Also, thegeology of the Eel River, in particular, is more erosive and prone tosedimentation events, suggesting that spawning habitat in the Eel River isof poorer quality than that in the Klamath and Rogue Rivers. Finally,evidence suggests that the Klamath and Rogue Rivers played a more importantrole in historic Yurok and Hoopa tribal sturgeon fisheries than the Eel andSouth Fork Trinity Rivers (FWS, 1981), again supporting the BRT'sconclusion that neither the Eel nor South Fork Trinity Rivers constitute asignificant portion of the Northern DPS' range.

Conclusion-Northern DPS

Based on the input provided by the BRT, we conclude that the NorthernDPS of green sturgeon is not in danger of extinction, nor likely to becomeendangered in the foreseeable future, in all or a significant portion ofits range. While a significant portion of the DPS' range would includeeither the Klamath or the Rogue Rivers, neither of these populations isregarded as being at risk of extirpation now or in the foreseeable future.The BRT was not convinced that green sturgeon were extirpated from theSouth Fork Trinity or Eel Rivers, even though it is likely that the EelRiver population, in particular, has suffered a severe reduction sincehistoric times. Reference data from salmonid habitat assessments andtribal fisheries data suggest that even though green sturgeon populationsin the Eel and South Fork Trinity Rivers are likely low, these rivers donot represent a significant portion of the DPS' range. The majority of theBRT felt that the presence of two well-separated and significant spawningpopulations in the Klamath and Rogue Rivers, and the effective reduction ingreen sturgeon catch due to implemented regulatory mechanisms, confer a lowlevel of risk to the DPS. A minority felt that overall paucity of datagenerates such uncertainty in green sturgeon status that the DPS' level ofextinction risk may be higher than available data appear to indicate. TheBRT expressed concern regarding the lack of data and monitoring efforts toadequately monitor the status of, and manage potential threats to, greensturgeon populations in this DPS. The BRT recommended that the NorthernDPS be placed on the Species of Concern List, that their status be reviewedin at least 5 years, and that population status monitoring be implementedimmediately.

Southern DPS

The BRT concluded that the Sacramento River contains the only knowngreen sturgeon spawning population in this DPS. There are no updatedpopulation trends data since the last status review. The BRT concludedthat there was almost certainly a substantial loss of spawning habitatbehind Keswick and Shasta dams (FWS, 1995b, historical habitat datasummarized in Lindley et al., 2004 for salmonids). Greensturgeon currently occur up to the impassible barrier at Keswick Dam (FWS,1995b). It is unlikely that green sturgeon reproduced in their currentspawning area under the historical temperature regime that occurred beforethe construction of Shasta and Keswick dams. At present, watertemperatures in the current spawning area are lower than they werehistorically due to releases from Shasta Dam. Prior to dam construction,green sturgeon would have had to migrate farther up the mainstem than theydo now in order to encounter water temperatures cool enough to triggerspawning. The BRT considered it possible that the additional habitatbehind Shasta Dam in the Pit, McCloud, and Little Sacramento systems wouldhave supported separate populations or at least a single, larger SacramentoRiver population less vulnerable to catastrophes than one confined to asingle mainstem, but the BRT was unable to be specific due to the paucityof historical information. The BRT expressed concern about the habitatlimitation and potential threats that green sturgeon faced in theSacramento River and again expressed particular concern about the highnumbers of juveniles entrained prior to 1986.

Juvenile entrainment data provide an indication of how abundance haschanged over time (1968-present). For the State facility (JohnSkinner Fish Facility; 1968-2001), the estimated average number ofgreen sturgeon taken per year prior to 1986 was 732; from 1986 on, theaverage number was 47. For the Federal facility (Tracy Fish CollectionFacility; 1980-2001), the average number prior to 1986 was 889; from1986 on, the average was 32. The significant reduction in numbers isconsistent across the State and Federal facilities and is also consistentwith significant reductions in estimated white sturgeon take within thesame time periods (NMFS, 2005). In addition, evidence indicates exportlevels at both facilities have increased substantially, particularly at theState facility since the 1970s and 1980s (as exhibited by yearly acre-feetexported from Federal and State facilities, NMFS, 2005). Though there aremany assumptions associated with fish salvage estimates at these facilities(i.e., estimates are expanded catches from brief sampling periods; CDFG,2002), this information may be the best available data in determining thepopulation trends of the Southern DPS.

The BRT concluded that an effective population of spawning greensturgeon does not exist in the Feather River. Although there is noevidence of spawning in the Feather River either in the past or now, thecontinued presence of adults in the system suggests that green sturgeon aretrying to migrate ito presumed spawning areas now blocked by Oroville Dam,suggesting in turn that spawning habitat on the Fraser River may bave beenlost. A substantial amount of habitat in the Feather River was lost withthe construction of Oroville Dam (constructed in 1961) and from thermalbarriers at the Thermalito Afterbay facility (CDFG, 2002). FWS (1995b)stated that “Evidence also suggests that [white] sturgeonreproduction occurs in both the Feather and Bear rivers.” Again, theBRT assumed that a similar suggestion could be made for green sturgeon inthe face of the paucity of data. Sturgeon (including some documented greensturgeon) still regularly occur in the Bear and Yuba Rivers (CDFG, 2002;Beamesderfer et al., 2004) and, therefore, must migratethrough the Feather River. Threats to green sturgeon are similar to thosefaced in the Sacramento River.

Though the BRT concluded that there was not sufficient information toestablish whether the San Joaquin River system once supported a viablegreen sturgeon population, we see no reason to exclude the San JoaquinRiver system as a possibly occupied watershed in the past based on similarconclusions reached for Chinook salmon habitat assessments in theSacramento and Feather Rivers. While some authors indicate that there isno evidence of green sturgeon occurrence or spawning in the San JoaquinRiver (Beamesderfer et al., 2004; Adams et al.,2002; CDFG, 2002), sampling effort has been extremely limited. Thus, noevidence of presence does not necessarily mean that green sturgeon do notoccur in this system. Moyle (2002) suggested that green sturgeonreproduction may have taken place in the San Joaquin River because numerousjuvenile green sturgeon have been captured at Santa Clara Shoal and BrannanIsland Recreational Area in the Delta. Both adult and juvenile greensturgeon salvage recoveries at the Federal facility, located closest to theSan Joaquin River, also provide some evidence that the San Joaquin Riversystem may at least be occupied by green sturgeon during parts of the year.The potential threats faced by green sturgeon if they do occur or occurredin the past in the San Joaquin system would be similar in nature to thosefaced in the Sacramento River, but would likely be more extreme becausethere are a greater number of impassable barriers in this system, many ofwhich lack fish passage structures, and flow rates are lower in the SanJoaquin than those in the Sacramento.

Conclusion-Southern DPS

The majority of the BRT concluded that the Southern DPS is likely tobecome endangered in the foreseeable future throughout all of its range.The BRT felt that the blockage of green sturgeon spawning from what werehistoric spawning areas above Shasta Dam (although it is unclear whetherthese were separate populations) and the accompanying decrease in spawningarea with the loss of a potential spawning area in the Feather River makegreen sturgeon in the Southern DPS likely to become endangered within theforeseeable future. We believe that the loss of potential spawning habitatin the San Joaquin River system also may have contributed to the overalldecline of the Southern DPS. The majority of the BRT also felt that theconcentration of spawning adults in the Sacramento River places this DPS ateven greater risk of extinction. No BRT members felt that the DPS was atimminent risk of extinction.

Efforts Being Made to Protect Green Sturgeon Back to Top

Section 4(b)(1)(A) of the ESA requires the Secretary of Commerce to makelisting determinations solely on the basis of the best scientific andcommercial data available after taking into account efforts being made toprotect a species. Therefore, in making its listing determinations, wefirst assess a DPS's level of extinction risk and identify factors thathave led to its decline. We then assess existing efforts being made toprotect the species to determine if those measures ameliorate the risksfaced by the DPS.

In judging the efficacy of existing protective efforts, we rely on thejoint NMFS-FWS “Policy for Evaluation of Conservation Efforts WhenMaking Listing Decisions” (“PECE;” 68 FR 15100; March 28,2003). PECE provides direction for the consideration of protective effortsidentified in conservation agreements, conservation plans, managementplans, or similar documents (developed by Federal agencies, state and localgovernments, Tribal governments, businesses, organizations, andindividuals) that have not yet been implemented, or have been implementedbut have not yet demonstrated effectiveness. The policy articulatesseveral criteria for evaluating the certainty of implementation andeffectiveness of protective efforts to aid in determining whether a speciesshould be listed as threatened or endangered. Evaluations of the certaintyan effort will be implemented include whether: the necessary resources(e.g., funding and staffing) are available; the requisite agreements havebeen formalized such that the necessary authority and regulatory mechanismsare in place; there is a schedule for completion and evaluation of thestated objectives; and (for voluntary efforts) the necessary incentives arein place to ensure adequate participation. The evaluation of the certaintyof an effort's effectiveness is made on the basis of whether the effort orplan: establishes specific conservation objectives; identifies thenecessary steps to reduce threats or factors for decline; includesquantifiable performance measures for the monitoring of compliance andeffectiveness; incorporates the principles of adaptive management; and islikely to improve the species' viability at the time of the listingdetermination.

PECE also notes several important caveats. Satisfaction of the abovementioned criteria for implementation and effectiveness establishes a givenprotective effort as a candidate for consideration, but does not mean thatan effort will ultimately change the risk assessment. The policy stressesthat just as listing determinations must be based on the viability of thespecies at the time of review, so they must be based on the state ofprotective efforts at the time of the listing determination. PECE does notprovide explicit guidance on how protective efforts affecting only aportion of a species' range may affect a listing determination, other thanto say that such efforts will be evaluated in the context of other effortsbeing made and the species' overall viability. There are circumstanceswhere threats are so imminent, widespread, and/or complex that it may beimpossible for any agreement or plan to include sufficient efforts toresult in a determination that listing is not warranted.

Conservation measures that may apply to listed species includeconservation measures implemented by tribes, states, foreign nations, localgovernments, and private organizations. Also, Federal, tribal, state, andforeign nations' recovery actions (16 U.S.C. 1533(f)), Federal consultationrequirements (16 U.S.C. 1536), and prohibitions on taking (16 U.S.C. 1538)constitute conservation measures. In addition, recognition through Federalgovernment or state listing promotes public awareness and conservationactions by Federal, state, tribal governments, foreign nations, privateorganizations, and individuals.

Fishing Regulations

Recent management strategies in Oregon and Washington have considerablyreduced the catch of green sturgeon. There are no targeted commercialfisheries on green sturgeon, and recreational fishing remains negligible.Commercial by-catch of green sturgeon occurs predominantly during the earlyfall salmon and white sturgeon fisheries in the lower Columbia River, whenthe green sturgeon have migrated into the estuary and lower river mainstem.Fisheries are timed to avoid coinciding with peak periods of green sturgeonpresence. Since 2002, Oregon and Washington have adopted daily landinglimits for sturgeon during fall Columbia River commercial salmon seasons.This management action has resulted in a significant decrease in greensturgeon catch due to the higher value (price per pound) of white sturgeonon the commercial market. Harvesters now typically release all greensturgeon (alive) to fill their weekly or daily landing limit with the morevaluable white sturgeon. Additionally, this management approach hasallowed the commercial fishery to access its allocation of white sturgeonprior to periods of peak green sturgeon presence and without any fisheriestargeting sturgeon, further minimizing green sturgeon by-catch.

Protective efforts on the Klamath and Trinity Rivers began with takelimits and maximum size ranges through the late 1970s, and between 1978 and1993 seasonal limits were imposed to prohibit the take of sturgeon in theKlamath River upstream of and including the Trinity River. All sturgeonfishing has been prohibited in the Klamath-Trinity system since 1993.Sturgeon fishing also has been prohibited since 1993 in all waters of theEel River from the mouth to rkm 153 including all waters of the South ForkEel River downstream of Benbow Dam (CDFG, 2002). Sturgeon fishing inrivers and bays in Del Norte and Humboldt Counties, including the SmithRiver, Humboldt and Arcata Bays, and all tidal waters, has been prohibitedsince 1993. General angling regulations apply to sturgeon angling fromMendocino County south (one fish per day between 117 and 183cm TL).

Both white and green sturgeon are protected by the same fishingregulations in the Sacramento-San Joaquin system. No commercial take ispermitted and angling take is restricted to one fish per day between 117and 183cm TL. An additional closure in central San Francisco Bay occursbetween January 1 and March 15, coinciding with the herring spawning seasonto protect sturgeon feeding on herring eggs (CDFG, 2002). Active sturgeonenforcement is often employed in areas where sturgeon are concentrated andparticularly vulnerable to the fishery.

There is no commercial fishery for green sturgeon in Canada, althoughthe species is taken as by-catch in white sturgeon and salmonfisheries.

Habitat Protection Efforts

In the United States, the Central Valley Project Improvement Act (CVPIA)is a Federal act directing the Secretary of the Interior to amend previousauthorizations of California's Central Valley Project to include fish andwildlife protection, restoration, and mitigation as project purposes havingequal priority with irrigation and domestic use, and fish and wildlifeenhancement as a project purpose equal to power generation. As a result ofthe CVPIA enacted in 1992, the FWS and U.S. Bureau of Reclamation have ledan effort to implement a significant number of activities across theCentral Valley including projects such as: river restoration; landpurchases; fish screen projects; water acquisitions for the environment;and special studies and investigations. The Anadromous Fish RestorationProgram (AFRP), a component of the CVPIA, implements a doubling program inan attempt to “implement a program which makes all reasonable effortsto ensure that, by the year 2002, natural production of anadromous fish inCentral Valley rivers and streams will be sustainable, on a long-termbasis, at levels not less than twice the average levels attained during theperiod of 1967-1991.” The AFRP specifically applies thedoubling effort toward Chinook salmon, Central Valley steelhead, stripedbass, and white and green sturgeon. Though most efforts of the AFRP haveprimarily focused on Chinook salmon as a result of their listing historyand status, green sturgeon may receive some unknown amount of benefit fromthese restoration efforts. For example, the acquisition of water for flowenhancement on tributaries to the Sacramento River, fish screening for theprotection of Chinook salmon and Central Valley steelhead, or riparianrevegetation and instream restoration projects would likely have someancillary benefits to sturgeon. The AFRP has also invested in one greensturgeon research project that has helped improve our understanding of thelife history requirements and temporal patterns of green sturgeon withinthe Southern DPS.

The California Bay-Delta Program (CALFED) is a cooperative effort ofmore than 20 State and Federal agencies designed to improve water qualityand reliability of California's water supply while recovering the CentralValley ecosystem. The CALFED program contains four key objectives whichinclude water quality, ecosystem quality, water supply and levee systemintegrity. Many notable beneficial actions have originated and been fundedby the CALFED program including such projects as floodplain and instreamrestoration, riparian habitat protection, fish screening and passageprojects, research regarding non-native invasive species and contaminants,restoration methods, and watershed stewardship and education and outreachprograms. Prior Federal Register notices have reviewed thedetails of CVPIA and CALFED programs and potential benefits towardsanadromous fish, particularly Chinook salmon and Central Valley steelhead(50 FR 33102).

Information received from CALFED regarding potential projects that couldbe regarded as conservation measures for green sturgeon indicated a totalof 118 projects of various types and levels of progress funded between 1995and 2004. Projects primarily consisted of fish screen evaluation andconstruction projects, restoration evaluation and enhancement activities,contaminations studies, and dissolved oxygen investigations related to theSan Joaquin River Deep Water Ship Channel. Two evaluation projectsspecifically addressed green sturgeon while the remaining projectsprimarily address anadromous fish in general, particularly listedsalmonids. The new green sturgeon information from research will be usedto enhance our understanding of the risk factors affecting the species,thereby improving our ability to develop effective management measures.However, at present they do not directly help to alleviate threats thatthis species faces in the wild. All ongoing fish screen and passagestudies are designed primarily to meet the minimum qualifications outlinedby the NMFS and CDFG fish screen criteria. Though these improvements willlikely benefit salmonids, there is no evidence showing that these measureswill decrease the likelihood of green sturgeon mortality. While one ofCALFED's goals is to recover a number of at-risk species (including greensturgeon) and the program has and continues to provide funding for avariety of laboratory-based research projects, there are no specificactions aimed at alleviating the primary risks that threaten the continuedexistence of green sturgeon in the wild.

Other potential conservation measures such as the opening of the RBDDgates have helped green sturgeon passage in the Sacramento River during theearly part of their spawning season, but it is not known how effective thismeasure has been. In addition, fish ladders in place are probably toosmall for green sturgeon to negotiate during the latter part of thespawning season when the RBDD gates are closed (FWS, 1995b). TheGlenn-Colusa Irrigation District plans to help reduce fish loss and enhancelong-term fish passage, but these measures are not yet underway. Fishsalvaging efforts at the Tracy Fish Collection Facility and the SkinnerDelta Fish Protective Facility in the South Delta have been operating fordecades, but it is unknown whether efforts to relocate adults have resultedin restoration of spawning potential and whether the salvage of juvenilesis effective.

As evaluated pursuant to PECE, the above described protective efforts donot as yet, individually or collectively, provide sufficient certainty ofimplementation and effectiveness to counter the extinction risk assessmentconclusion that the Southern DPS is likely to become an endangered speciesin the foreseeable future throughout its range.

Green sturgeon are listed as Species of Special Concern under Canada'sSpecies at Risk Act (SARA). Under SARA a Species of Special Concern is awildlife species that may become a threatened or an endangered speciesbecause of a combination of biological characteristics and identifiedthreats. There are no specific conservation measures directed at greensturgeon in Canada to alleviate the recognized threats of habitatdegradation and alteration.

Proposed Determinations Back to Top

Section 4(b)(1) of the ESA requires that the listing determination bebased solely on the best scientific and commercial data available, afterconducting a review of the status of the species and after taking intoaccount those efforts, if any, being made by any state or foreign nation toprotect and conserve the species. We have reviewed the petition, thereports of the BRT (NMFS, 2002, 2004), co-manager comments, and otheravailable published and unpublished information, and we have consulted withspecies experts and other individuals familiar with green sturgeon. On thebasis of the best available scientific and commercial information, thesouthern and northern populations of green sturgeon meet the discretenessand significance criteria for distinct DPSs.

Northern DPS

Informed by the BRT's risk assessment, we conclude that the Northern DPSis not presently in danger of extinction or likely to become so in theforeseeable future throughout all or a significant portion of its range.Accordingly, the DPS does not warrant listing under the ESA at this time.Our review indicates that: (1) there is no evidence for reductions inspawning habitat in the South Fork Trinity River; and (2) the Eel Riverpopulation may have experienced declines and loss of spawning habitat.Nevertheless, the BRT concluded that neither the South Fork Trinity nor theEel River constitute a significant portion of the DPS' range because: (1)analogies drawn from salmonid research suggest that the South Fork Trinityand Eel Rivers do not support large salmonid populations; (2) habitat inthe Eel River is of poorer quality compared to that of the Klamath andRogue Rivers; and (3) tribal fisheries data do not suggest that the SouthFork Trinity or Eel River supported significant numbers of green sturgeonin the past. Due to the poor availability of data and attendantuncertainties regarding the status of and threats facing the species, wewill maintain the Northern DPS on the Species of Concern List. We willre-evaluate the status of the Northern DPS in 5 years provided sufficientnew information becomes available indicating that a status review update iswarranted.

Southern DPS

We propose to find that the Southern DPS is not presently in danger ofextinction throughout all of its range. Fishing regulations in place inCalifornia, the implementation of studies aimed at increasing ourunderstanding of the ecological requirements of green sturgeon in the wild,and efforts to ameliorate threats to salmonids in the wild, thus conferringsome possible benefits to green sturgeon, indicate that the Southern DPS isnot presently in danger of extinction throughout all of its range. We alsopropose to find that the Southern DPS is not in danger of extinctionthroughout a significant portion of its range. We feel that spawninghabitat may have been lost in the Sacramento and Feather Rivers, but due toa paucity of data, we are unable to determine the geographic extent anddemographic consequences of this loss. We have no evidence of historic orcurrent spawning in the San Joaquin River and therefore we have no evidenceof lost spawning habitat.

Based on our evaluation of the best available scientific information andthe ongoing state and Federal conservation efforts, we propose to find thatthe Southern DPS is likely to become endangered in the foreseeable futurethroughout all of its range and should therefore be listed as threatened.This proposal is based on the reduction of potential spawning habitat, thethreats to the single remaining spawning population remaining severe andunlikely to be sufficiently alleviated by conservation measures currentlyin place, and the downward trend of sturgeon salvage estimates from State(1968-2003) and Federal (1980-2003) facilities.

Take Prohibitions and Protective Regulations

Section 9 of the ESA prohibits certain activities that directly orindirectly affect endangered species. In the case of threatened species,ESA section 4(d) authorizes the Secretary to issue regulations he considersnecessary and appropriate for the conservation of the species. We haveflexibility under section 4(d) to tailor protective regulations based onthe contents of available conservation measures. The 4(d) protectiveregulations may prohibit, with respect to threatened species, some or allof the acts which section 9(a) of the ESA prohibits with respect toendangered species. These 9(a) prohibitions and 4(d) regulations apply toall individuals, organizations, and agencies subject to U.S. jurisdiction.We will evaluate protective regulations pursuant to section 4(d) for theSouthern green sturgeon DPS and propose any thought to be necessary andappropriate for conservation of the species in a forthcoming notice ofproposed rulemaking that will be published in the FederalRegister.

Other Protective Regulations

Section 7(a)(2) of the ESA and NMFS/FWS regulations require Federalagencies to confer with us on actions likely to jeopardize the continuedexistence of species proposed for listing or result in the destruction oradverse modification of proposed critical habitat. If a proposed speciesis ultimately listed, Federal agencies must consult on any action theyauthorize, fund, or carry out if those actions may affect the listedspecies or its critical habitat. Examples of Federal actions that mayaffect the Southern green sturgeon DPS include: water diversion for humanuse; point and non-point source discharge of persistent contaminants;contaminated waste disposal; water quality standards; and fisherymanagement practices.

Service Policy on the Role of Peer Review Back to Top

On July 1, 1994, we and FWS published a series of policies regardinglistings under the ESA, including a policy for peer review of scientificdata (59 FR 34270). The intent of the peer review policy is to ensure thatlistings are based on the best scientific and commercial data available.Prior to a final listing, we will solicit the expert opinions of threequalified specialists, concurrent with the public comment period.Independent specialists will be selected from the academic and scientificcommunity, Federal and state agencies, and the private sector.

Critical Habitat Back to Top

Critical habitat is defined in section 3 of the ESA as: “(i) thespecific areas within the geographical area occupied by the species, at thetime it is listed in accordance with the provisions of section 4 of thisAct, on which are found those physical or biological features (I) essentialto the conservation of the species and (II) which may require specialmanagement considerations or protection; and (ii) specific areas outsidethe geographical area occupied by the species at the time it is listed inaccordance with the provisions of section 4 of this Act, upon adetermination by the Secretary that such areas are essential for theconservation of the species” (16 U.S.C. 1532(5)(A)).“Conservation” means the use of all methods and proceduresneeded to bring the species to the point at which listing under the ESA isno longer necessary (16 U.S.C. 1532(3)). Section 4(a)(3)(A) of the ESArequires that, to the maximum extent prudent and determinable, criticalhabitat be designated concurrently with the listing of a species (16 U.S.C.1533(a)(3)(A)(i)). Designations of critical habitat must be based on thebest scientific data available and must take into consideration theeconomic, national security, and other relevant impacts of specifying anyparticular area as critical habitat. Once critical habitat is designated,section 7 of the ESA requires Federal agencies to ensure that they do notfund, authorize or carry out any actions that are likely to destroy oradversely modify that habitat. This requirement is in addition to thesection 7 requirement that Federal agencies ensure that their actions donot jeopardize the continued existence of listed species. We are currentlycompiling information to prepare a critical habitat proposal for theSouthern DPS. In a previous Federal Register notice (66 FR64793; December 14, 2001) we requested specific information on criticalhabitat and are again seeking public input and information to assist ingathering and analyzing the best available scientific data to support acritical habitat designation. We will continue to meet with co-managersand other stakeholders to review this information and the overalldesignation process. We will then initiate rulemaking with the publicationof a proposed designation of critical habitat, opening a period for publiccomment and the opportunity for public hearings. Joint NMFS/FWSregulations for listing endangered and threatened species and designatingcritical habitat at 50 CFR 424.12(b) state that the agency “shallconsider those physical and biological features that are essential to theconservation of a given species and that may require special managementconsiderations or protection” (hereafter also referred to as“essential features.” Pursuant to the regulations, suchrequirements include, but are not limited to the following: (1) space forindividual and population growth, and for normal behavior; (2) food, water,air, light, minerals, or other nutritional or physiological requirements;(3) cover or shelter; (4) sites for breeding, reproduction, rearing ofoffspring, germination, or seed dispersal; and generally; (5) habitats thatare protected from disturbance or are representative of the historicgeographical and ecological distributions of a species. These regulationsgo on to emphasize that the agency shall focus on essential features withinthe specific areas considered for designation. These features ''mayinclude, but are not limited to, the following: spawning sites, feedingsites, seasonal wetland or dryland, water quality or quantity, geologicalformation, vegetation type, tide, and specific soil types.''

Public Comments Solicited Back to Top

We recognize that there are serious limits to the quality of informationavailable, and, therefore, we exercised our best professional judgment indeveloping this proposal to list the Southern DPS. To ensure that thefinal action resulting from this proposal will be as accurate and effectiveas possible, we are soliciting comments and suggestions from the public,other governmental agencies, the Government of Canada, the scientificcommunity, industry, environmental groups, and any other interestedparties. Comments are encouraged on this proposal (See DATES and ADDRESSES). Specifically, we are interested ininformation regarding: (1) green sturgeon spawning habitat within therange of the Southern DPS that was present in the past, but may have beenlost over time (2) biological or other relevant data concerning any threatsto the Southern green sturgeon DPS; (3) the range, distribution, andabundance of the Southern DPS; (4) current or planned activities within therange of the Southern DPS and their possible impact on the Southern DPS;and (5) efforts being made to protect the Southern DPS.

We are also requesting quantitative evaluations describing the qualityand extent of freshwater and marine habitats for juvenile and adult greensturgeon as well as information on areas that may qualify as criticalhabitat in California for the proposed Southern DPS. Specific areas thatinclude the physical and biological features essential to the recovery ofthe DPS should be identified. We recognize that there are areas within theproposed boundaries of the Southern DPS that historically constituted greensturgeon habitat, but may not be currently occupied by green sturgeon. Weare requesting information about these currently unoccupied areas to helpus determine whether these areas are essential to the recovery of thespecies or excluded from designation. For areas potentially qualifying ascritical habitat, we are requesting information describing: (1) theactivities that affect the area or could be affected by the designation,and (2) the economic costs and benefits of additional requirements ofmanagement measures likely to result from the designation. The economiccost to be considered in the critical habitat designation under the ESA isthe probable economic impact “of the [critical habitat] designationupon proposed or ongoing activities” (50 CFR 424.19). Economiceffects attributable to listing include actions resulting from section 7consultations under the ESA to avoid jeopardy to the species. Commentsconcerning economic impacts should attempt to distinguish the costs oflisting from the incremental costs that can be directly attributed to thedesignation of specific areas as critical habitat.

We will review all public comments and any additional informationregarding the status of, and critical habitat for, the Southern greensturgeon DPS in developing a final listing determination as well asproposed critical habitat and, potentially, section 4(d) regulations.

Public Hearings Back to Top

Public hearings will be held in several locations within the range ofthe proposed Southern DPS; details regarding locations, dates, and timeswill be published in a forthcoming Federal Register notice.

References Back to Top

A complete list of all references cited herein is available upon request(see ADDRESSES section).

Classification Back to Top

National Environmental Policy Act

The 1982 amendments to the ESA, in section 4(b)(1)(A), restrict theinformation that may be considered when assessing species for listing.Based on this limitation of criteria for a listing decision and the opinionin Pacific Legal Foundation v. Andrus, 675 F. 2d 825 (6th Cir. 1981), wehave concluded that ESA listing actions are not subject to theenvironmental assessment requirements of the National Environmental PolicyAct. (See NOAA Administrative Order 216 6.)

Executive Order 12866, Regulatory Flexibility Act and PaperworkReduction Act

As noted in the Conference Report on the 1982 amendments to the ESA,economic impacts cannot be considered when assessing the status of aspecies. Therefore, the economic analysis requirements of the RegulatoryFlexibility Act are not applicable to the listing process. In addition,this rule is exempt from review under Executive Order 12866. This proposedrule does not contain a collection-of-information requirement for thepurposes of the Paperwork Reduction Act.


In keeping with the intent of the Administration and Congress to providecontinuing and meaningful dialogue on issues of mutual State and Federalinterest, this proposed rule will be given to the relevant state agenciesin each state in which the species is believed to occur, who will beinvited to comment. We have conferred with the States of Washington,Oregon and California in the course of assessing the status of the SouthernDPS, and considered, among other things, Federal, state and localconservation measures. As we proceed, we intend to continue engaging ininformal and formal contacts with the States, and other affected local orregional entities, giving careful consideration to all written and oralcomments received. We also intend to consult with appropriate electedofficials in the establishment of a final rule.

List of Subjects in 50 CFR Part 223 Back to Top

Dated: March 28, 2005.

William T. Hogarth,

Assistant Administrator for Fisheries, National Marine FisheriesService.

For the reasons set out in the preamble, 50 CFR part 223 is proposed tobe amended as follows:

begin regulatory text


end regulatory text

1. The authority citation for part 223 continues to read asfollows:

Authority: Back to Top

16 U.S.C. 1531 1543; subpart B,§ 223.12 also issued under 16 U.S.C. 1361 etseq.

2. In § 223.102, amend paragraph (a) by adding andreserving paragraph (a)(23) and paragraph (a)(24) and adding a new paragraph (a)(25) to read as follows:

§ 223.102 Enumeration ofthreatened marine and anadromous species.

(a) * * *

(25) North American green sturgeon-southern DPS (Acipenser medirostris). California. The southern DPS includesall spawning populations of green sturgeon south of the Eel River(exclusive), principally including the Sacramento River green sturgeonspawning population.

* * * * *

[FR Doc. 05-6611 Filed 4-5-05; 8:45 am]


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