Comment: Black Abalone Critical Habitat Must Protect

the Species’ Larvae, and not Just Adults.

Docket ID: NOAA-NMFS-2010-0191

[Name redacted], Ph.D.

October 7, 2010

The Proposed Rulemaking To Designate Critical Habitat for Black Abalone takes strong and laudable steps to safeguard the future of Haliotis cracherodii.  In particular, the inclusion of suitable water quality and larval settlement substrate are impressive strides towards linking the biology of the species with its protection under the Endangered Species Act (ESA).  One further step that the agency should take is designating as critical certain ocean water habitat for the larvae themselves, in order to lend protection to the species throughout its life cycle, and guarding even the most vulnerable life stages.  Each of the specific habitats listed in the Proposed Rule include only the rocky intertidal habitat, neglecting habitat for the critical larval stages.  Below I set out the logic for this suggestion and propose a means of implementation.

I. Species’ larvae, and not just adults, are protected under the Endangered Species Act

There is no question that the Act covers even the very small larval stages of listed species.  Three lines of evidence make this clear: the text of the Act itself and its associated regulations, past agency practice, and the limited case law on analogous questions in vertebrate species. 

            The language of the ESA is remarkably broad in its coverage of listed species, and explicitly protects its different life stages, parts and products. The Definitions section provides:

The term “species” includes any subspecies of fish or wildlife or plants … which interbreeds when mature.[1]  …

The term ‘fish or wildlife’ means any member of the animal kingdom, including without limitation any mammal, fish, bird … amphibian, reptile, mollusk, crustacean, arthropod or other invertebrate, and includes any part, product, egg, or offspring thereof, or the dead body or parts thereof.[2]

Read together, these definitions cover any part or product of any listed species, even singling out some invertebrate groups by name.  The federal rules governing the ESA’s interpretation mirror the Act’s broad definitional language,[3] and the legislative history emphasizes the ESA’s inclusive aim, with the final Senate report highlighting the “broad” definition of covered organisms.[4]  The larval stages of listed invertebrates thus fall squarely within the Act’s ambit: a protected species is protected at all stages of its life cycle.[5]

            Federal administrative agency practice is also consistent with ESA protection for the larvae, gametes, and juveniles of listed species.  This issue primarily arises in the context of threatened and endangered salmonid[6] fishes.  Because they live in aquatic environments and produce hundreds of thousands of larvae each year, a small number of which survive to adulthood, these fishes are fairly precise analogs for listed invertebrate species.  NOAA has levied substantial civil penalties under the ESA against violators for take of endangered fry[7] or juvenile fishes,[8] for example, and other agencies have explicitly considered protections for fry in their decisions.[9]  The text of the Act gives no reason to suspect that listed invertebrates merit less protection than vertebrates in this respect.[10]

            Endangered species status reviews, mandated under the ESA,[11] also attest to agency treatment of juveniles and larvae as covered by the law.  NMFS’s status review of the white abalone in 2000, for example, discussed potential effects of climate change on the species’ larval stages,[12] and salmonid fry are mentioned throughout the nearly 600-page omnibus 2005 status review of west coast salmon and steelhead.[13]  Agency Biological Opinions (BiOps), required under the ESA’s section 7 consultation provision for federal agency actions that may impact listed species, also routinely mention larvae and juveniles of listed species.[14]

The relevant case law further substantiates the ESA’s protections for larvae and juveniles. Most obviously, entraining and harming the fry of listed salmonid species amounts to “take.”[15] More subtly and most often, courts in general treat salmonid fry and adults as equally protected without distinguishing between the two.[16] Importantly, this treatment is consistent independent of whether the court’s decision tends to strengthen or weaken as-applied protections in any given case.  In the few cases dealing with the larvae of non-salmonid species, courts have not addressed the question directly, but rather proceeded assuming that the ESA covers the larvae as well as the adults.[17]    

 Thus the broad statutory language, past agency practice, and the little relevant case law all indicate that the ESA’s protections encompass the larval and juvenile stages of listed species.

II. How does the presence of larvae and juveniles impact the designation of critical habitat? Is that habitat occupied if larvae are found in it seasonally or occasionally?

 In designating the critical habitat of protected species, the agency must specify habitat features essential to the conservation of the species, known as Primary Constituent Elements.[18]  Because “conservation” here refers not just to species maintenance but also recovery,[19] citizen suits can force the agency to include those habitat elements necessary for the recovery of the species, even if they are unnecessary for its mere survival.  In practice, NMFS already evaluates Primary Constituent Elements for salmonid larvae and juveniles, highlighting the unique requirements of these early life stages.[20]

One practical effect of designating critical habitat is that, under section 7, other federal agencies must consult with the listing agency before undertaking any action that would adversely modify the primary constituent elements of a listed species’ critical habitat.[21]  Critical habitat in the nearshore marine environment therefore has the potential to trigger consultation for a broad swath of federal actions such as dredging and filling,[22] licensing for commercial fishing,[23] issuing Clean Water Act discharge permits,[24] permitting extraction of offshore petroleum or mineral reserves,[25] licensing power plants that intake coastal water,[26] and any federally-funded construction that impacts the coastal ocean and may significantly harm designated critical habitat.  Clearly, how the listing agencies define critical habitat for imperiled species could hugely impact federal activities along the coasts.[27]

a. Critical habitat for marine species, and marine invertebrates in particular

Critical habitat for listed vertebrates, such as marine mammal species, has not generated much controversy.[28]  But invertebrates pose a different challenge, again because of the animals’ biology: species’ habitat requirements are often totally different during different life stages. Invertebrate larvae also highlight a key distinction between terrestrial and marine habitat that is often overlooked: whereas species’ habitat on land occupies a two-dimensional area, marine species live in a three-dimensional volume.  Adult corals, for example, require submerged but shallow areas with hard substrate on which to grow, while coral larvae require open water through which to disperse.[29]  A critical habitat designation effective across the corals’ entire life cycles, therefore, would include not just the submarine substrate where adult corals are likely to occur, but also the volume of water through which the larvae are likely to travel.[30]  The existing and proposed critical habitat designations for the Leatherback Turtle, for example, both explicitly include the ocean water itself, through which the turtles necessarily must swim.[31]

The agencies’ interpretive guidelines require that the designating agency consider such factors as “sites for breeding, reproduction, rearing of offspring, germination, or seed dispersal.”[32]  While “germination” and “seed dispersal” appear to apply specifically to plants in this context, they express the breadth and aim of the habitat requirements the rules cover.  In the context of marine invertebrates, then, the agency must consider habitat necessary for the fertilization and dispersal of animal larval forms, integral to “breeding” and “reproduction” and precisely analogous to “seed dispersal.”  Moreover, the guidelines’ criteria are not exhaustive, and the agencies are free to consider other factors that are essential to a given species.[33]

Because at present the critical habitat does not clearly include the water itself in addition to the substrate, it is not obvious whether the only existing designated critical habitat for marine invertebrate species meets the statutory and regulatory criteria.

Existing designated critical habitat for coral species

NMFS designated critical habitat for the two threatened coral species in 2008.[34]  In doing so, the agency identified the physical feature essential to the species’ conservation as “substrate of suitable quality and availability to support larval settlement and recruitment.”[35]  Using the word “substrate” suggests that only the sea floor, and not the water itself, is included in the critical habitat.[36]  “Settlement” and “recruitment” are similarly life history milestones that occur on the sea floor rather than suspended in the water column.  These terms, coupled with ambiguous language in the rest of the regulation, leaves in doubt whether the coral species’ critical habitat includes the open water above such substrate.

An informatively analogous set of species, the freshwater mussels, receives different treatment.  FWS includes sufficient water flow and water quality as primary constituent elements of the mussels’ critical habitats, indicating that the habitat is not merely the substrate but also the water above that substrate.[37]  By contrast, NMFS explicitly rejected a comment that would have included sufficient water quality and temperature as elements of the corals’ critical habitat.[38]  The agency considered these elements redundant, reasoning that suitable substrate would reflect water of sufficient quality.[39]  As a result, the agency has not yet wrestled with the tricky issues that arise when a transient volume of ocean water might be protected habitat.[40]

NMFS has yet to designate habitat for the other two listed marine invertebrate species, the abalones, determining that it was not prudent to do so for the white abalone,[41] and that critical habitat was not yet determinable for the black abalone.[42]  The protections for these two species are consequently incomplete. Abalone species have life cycles similar to those of the corals, with similar planktonic larval periods,[43] and so share the difficulties inherent in designating habitat for these mercurial animals. 

The proposed critical habitat for black abalone,[44] encouragingly, includes sufficient water quality and substrate for juvenile settlement.  However it neglects to designate the water itself as habitat for the critical larval stage of the species.

b. Better accommodating invertebrates’ life cycles in designating critical habitat

Whether habitat is occupied is not dispositive in designating that habitat as critical: the agencies may designate unoccupied or occupied habitat, and as noted above, even occupied habitat is often not designated as critical.[45]  As a practical matter, however, the listing agency is much more likely to designate already-occupied habitat as critical.[46]  Therefore a threshold conceptual issue might be whether a given patch of water is “occupied” if a species’ larvae or juveniles are found there: if a habitat could be considered occupied, it would likely be politically easier for the agency to designate it for protection.

By definition, larvae and juveniles are transient forms, short-lived phases on the path to an adult form. In the case of many species, these immature forms are the primary means of dispersal and genetic exchange between populations.[47]  As a result many species’ larvae are transported widely by ocean currents and occur only at low densities in a given volume of water.  Precisely these same properties make them difficult cases under the ESA: rather than definitively occupying habitat, such as a bald eagle might, marine larvae exist in a given volume of ocean water probabilistically.  Whether larvae occur in a particular place at a particular time is a function of the overall abundance of that species’ larvae, and the spatial or temporal variance in that abundance. 

Table 1: Abundance and spatial/temporal variance as two major conceptual axes in determining whether a species' larvae "occupies" a habitat.

            Table 1 provides a useful framework for thinking about whether a species’ larvae “occupies” a particular volume of water as its habitat.[48]  As a normative starting point, it would make sense that the more likely a species’ larvae is to be found in a given volume of water, the more likely that volume of water should be designated critical habitat.  But such a sliding-scale must be calibrated for each particular species; low-fecundity species are perhaps more likely to be endangered, and it would be nonsensical to eliminate habitat from being designated as critical merely because such a species only occurs there at low density.[49]  After all, low and declining population numbers is a primary motivation for ESA protections in the first place.

The top-right quadrant of Table 1 – waters with predictably high abundances of a listed species’ larvae – are the easiest case, analogous to habitat occupied by terrestrial species.  This is water in which one can often find the listed species, and thus it is “occupied.”  The bottom-left quadrant, by contrast, is the hardest case: it seems the least likely to be designated as “occupied,” but on occasion, this water has high densities of low-fecundity species’ larvae, probably an important conservation target.  Though ultimately designating critical habitat is a policy decision in which larval abundance and variance should weigh as factors, it is important to note that higher- and lower-fecundity species will demand different standards for determining whether their larvae “occupy” a particular volume of habitat.         

            Habitat need not be occupied continuously, or at all, to be designated as critical.  Most relevantly, those areas of habitat that “support one or more life stages” may be protected, including sites for “incubation and larval development.”[50]  The present ESA regulations, therefore, do not bar NMFS from designating critical habitat that includes the water above the substrate merely because the adults of the listed species do not occupy that habitat.  Instead, the regulations would seem to require the water be included, because it is quite literally essential for the species’ conservation, survival, and recovery.[51]  Just as in the case of the leatherback turtle, where the existing and proposed critical habitat includes the volume of water in which the species spends much of its life, the ocean water itself – in which the invertebrates spend their lives and through which their larval and juvenile stages must travel – is clearly a “principle biological or physical constituent element[]”[52] of the listed species’ habitat.  It borders on irrational to exclude from designation the volume of seawater in which invertebrates must exist.

An open question worth exploring is whether habitat may be designated as critical only intermittently – for example, seasonally or only during breeding periods – or even whether mobile designated habitat is permissible.  If temporal flexibility were feasible, it would likely make designating critical habitat for larvae more politically palatable.  Similarly, designating critical habitat that moved along with the protected species could minimize the political fallout that would attend, say, designating the entire California coast as critical black abalone habitat.

While the FWS/NMFS Joint Regulations that govern critical habitat designation bar the use of “ephemeral” reference points for defining critical habitat,[53] they do not appear to bar temporary or intermittent critical habitat designation.  The boundaries of critical habitat can be dynamic if long-lasting (i.e., not ephemeral),[54] and it would seem technically feasible to overcome the notice problems that a spatially and temporally dynamic designation would cause.  In the simplest case, NMFS could establish Summer and Winter critical habitat that tracked the locations of adults and larvae, and publish a schedule of habitat designations in the Federal Register, broadcasting seasonal designations via standard media and GPS as the relevant dates approached.[55]  This would mainly impact federal agencies,[56] which would perhaps be more on notice than private citizens. 

III.  Concluding Statement

The agency should designate a portion of the ocean water itself as critical habitat for the black abalone’s larval stages, in one manner or another.  Above I have suggested one way in which this might be accomplished, but surely there are many others.

Sources

[1] 16 U.S.C. § 1532 (16)(emphasis mine).  Note also that the inclusion of the phrase "when mature" suggests that immature individuals are similarly encompassed by the term “species.” Presumably, membership in a “species” for the purposes of the ESA does not vary over the course of an individual’s lifetime. 

[2] 16 U.S.C. § 1532 (8)(emphasis mine). 

[3] See 50 C.F.R. § 424.02(n).

[4] See S. Rep. 93-307 at 2295 (1973). 

[5] Note that there is a logical requirement, too, that the Act cover all life stages. A species’ survival (to say nothing of recovery) is dependent on its individuals completing development and reproducing.  It would undermine the purposes of the ESA, and would be incredibly wasteful, to protect the adults of a species and not the larvae. The vertebrate equivalent would be ensuring the grizzly bears’ persistence by banning the hunting of adults while allowing open season on the cubs.

[6] Salmon species and their close relatives. 

[7] Salmonids first hatch from eggs into a larval stage, during which time they are known as “fry.” They subsequently become juveniles, before reaching maturity after spending months to years in their natal stream.   See, for example, the NMFS informational page on Chinook salmon: http://www.nmfs.noaa.gov/pr/species/fish/chinooksalmon.htm (accessed April 9, 2010).  I refer to fry and larvae interchangeably.

[8] In re: Anderson-Cottonwood Irrigation District, 1992 WL 347583 (NOAA)(levying $700,000 fine against small irrigation district for entraining endangered Chinook salmon fry). The parallel state case cited California Department of Fish & Game estimates that fewer than 2.5% of the salmon run’s fry had been entrained, see 92 Daily Journal D.A.R. 11723.

[9] See, e.g., City of Seattle, Washington, 1995 WL 301337 (FERC)(Federal Energy Regulatory Commission approving and licensing hydropower plan which included protections for endangered salmon and steelhead fry); Pub. Util. Dist. Chelan Co., Washington, 2002 WL 398316 (FERC)(similar).

[10] While the Distinct Population Segments (DPS) provision of the ESA’s section 4 only applies to vertebrates, 16 U.S.C. 35 §1532, section 4’s definitions don’t discriminate between invertebrate and vertebrate animals.  Further, Congress amended the law in 1978 to favor vertebrates in the DPS definition, and the other sections were not changed. See H.R. Conf. Rep. 95-1804 at 9485 (1978); P.L. 95-632.

[11] 16 U.S.C. 35 §1533(c).

[12] Alistair J. Hobday and Mia J. Tegner, Status Review of White Abalone (Haliotis sorenseni) Throughout its Range in California and Mexico, NOAA-TM-NMFS-SWR-035 (2000) at 35.

[13] Good, T.P., R.S. Waples, and P. Adams (editors). 2005. Updated status of federally listed ESUs of West Coast salmon and steelhead. U.S. Dept. Commer., NOAA Tech. Memo. NMFS-NWFSC-66.

[14] For a discussion of one such example, see Holly Doremus & A. Dan Tarlock, Fish, Farms, and the Clash of Cultures in the Klamath Basin, 30 Ecology L.Q. 279, 328-29 (2003)(“In its BiOp, FWS … concluded that the proposed project operations would jeopardize the key Upper Klamath Lake populations of both sucker species for several reasons. First, screening of A Canal would reduce entrainment of juveniles but not larvae, and entrainment would continue at Link River Dam…The agency went to great pains to explain how water depth could affect dissolved oxygen, pH, nutrient availability and algal blooms, and set out evidence supporting those connections. It also detailed the precise relationship between changes in lake depth and availability of habitats suitable for spawning, larvae, juvenile, and adult fish")(emphases mine).  See also Kristin Carden, Bridging the Divide: The Role of Science in Species Conservation Law, 30 Harv. Envtl. L. Rev. 165, 254 (2006).

[15] United States v. Glenn-Colusa Irr. Dist., 788 F. Supp. 1126, 1131 (E.D. Cal. 1992)

[16] See, e.g., NRDC v. Kempthorne, 2007 WL 4462395 (E.D. Cal. Dec. 14, 2007)(discussing Delta smelt larvae and juveniles as protected); Forest Conservation Council v. Espy, 835 F. Supp. 1202 (D. Idaho 1993) aff'd, 42 F.3d 1399 (9th Cir. 1994)(Finding NMFS’s treatment of salmon eggs and fry, among other issues, satisfied ESA consultation requirements); Pac. Coast Fed'n of Fishermen's Ass’ns v. Gutierrez, 606 F. Supp. 2d 1122, 1174 (E.D. Cal. 2008)(reviewing NMFS’s Biological Opinion concerning loss of salmon eggs and fry).

[17] See Pac. Shores Subdivision Cal. Water Dist. v. U.S. Army Corps of Eng’rs, 538 F. Supp. 2d 242 (D.D.C. 2008)(Oregon Silverspot Butterfly); Middle Rio Grande Conservancy Dist. v. Babbitt, 206 F. Supp. 2d 1156, 1187 (D.N.M. 2000) aff'd sub nom. Middle Rio Grande Conservancy Dist. v. Norton, 294 F.3d 1220 (10th Cir. 2002)(Spikedace and Loach Minnow); Ctr. for Biological Diversity v. U.S. Fish & Wildlife Serv., 2005 WL 2000928 (N.D. Cal. Aug. 19, 2005)(Tiger Salamander).

[18] 50 C.F.R. § 424.12 (“When considering the designation of critical habitat, the Secretary shall focus on the principal biological or physical constituent elements within the defined area that are essential to the conservation of the species. Known primary constituent elements shall be listed with the critical habitat description. Primary constituent elements may include, but are not limited to, the following: roost sites, nesting grounds, spawning sites, feeding sites, seasonal wetland or dryland, water quality or quantity, host species or plant pollinator, geological formation, vegetation type, tide, and specific soil types.”) See also Arizona Cattle Growers’ Ass’n v. Kempthorne, 534 F. Supp. 2d 1013, 1021-22 (D. Ariz. 2008)(discussing the requirement for primary constituent elements in habitat designation in upholding FWS’s habitat designation for the Mexican Spotted Owl); Home Builders Ass'n v. US Fish and Wildlife Service, 268 F. Supp. 2d 1197, 1211-1213 (E.D. Cal. 2003)(vacating critical habitat designation for the Alameda Whipsnake for want of sufficient description of the habitat’s primary constituent elements.)

[19] 16 U.S.C. 35 § 1532 defines “conservation” as methods necessary to bring the listed species to a point where it no longer needs protection; see also 50 C.F.R. 424.02(c)(same).

[20] See U.S. Fish and Wildlife Service, Formal Endangered Species Act Consultation on the Proposed Coordinated Operations of the Central Valley Project (CVP) and State Water Project (SWP), Document 81420-2008-F-1482-5 (2008) at 240 (listing PCEs for spawning and larval/juvenile transport) )(hereafter, “Delta Smelt BiOp”).

[21] 16 U.S.C. 35 § 1536(a)(2). The other effect of section 7 consultation is that agencies must ensure they do not jeopardize the existence of a listed species.  Id.  Section 7 is discussed elsewhere in this paper. 

[22] Dredge and fill is regulated by section 404 of the Clean Water Act, codified at 33 U.S.C. § 1344.  Clearly, any dredge or fill operations in the vicinity of listed nearshore species have the potential to cause harm to the species and their critical habitat.

[23] See Strahan v. Coxe, 127 F.3d 155 (1st Cir. 1997)(upholding the District court’s ruling requiring the State of Massachusetts to apply for an Incidental Take Permit under the ESA before issuing commercial fishing licenses, as fishing practices caused harm to listed Northern Right Whales.)

[24] The National Pollution Discharge Elimination System (NPDES), codified at 33 U.S.C. § 1342, regulates point sources of water pollution.  Such point sources can, and likely do, impact listed marine species, but because most states administer their own NPDES permitting systems, the federal government has limited authority to require section 7 consultation associated with permitting.  See American Forest and Paper Ass’n v. EPA, 137 F.3d 291, 294 (5th Cir. 1998).  However, as discussed below, the U.S. EPA still administers the NPDES program for some critical U.S. territories, for which permits would be subject to ESA section 7 consultation.

[25] The U.S. Department of the Interior’s Bureau of Ocean Energy Management, Regulation, and Enforcement – formerly the Minerals Management Service – controls oil and gas leases more than three miles offshore, under the Outer Continental Shelf Lands Act of 1953, 43 U.S.C. § 1331; see also Federal Oil & Gas Royalty Management Act of 1982, 30 U.S.C. § 1701 et seq.  Natural resources extraction is likely to impact listed species, and therefore requires ESA section 7 consultation.

[26] Flow-through cooling water, which many power plants use, is also regulated by the Clean Water Act; see 33 U.S.C. § 1342.

[27] Note, too, that these same coastal areas are home to some of the densest development and highest property values in the US, and consequently they have experienced intense environmental degradation already.  This makes conserving critical habitat for threatened and endangered species all the more politically challenging.

[28] But see Strahan v Coxe, supra note 43; NRDC v. Evans, 279 F. Supp. 2d 1129, 1177 (N.D. Cal. 2003)(challenging Navy operations in the Pacific that might impact the designated critical habitat of listed marine mammals.)

[29] These habitat characteristics are merely illustrative; see 73 Fed. Reg. 72210, 72214 for the actual (very brief) coral habitat designation, as well as the coral habitat Primary Constituent Elements, discussed below.

[30] A closely related question, touched on below in section 4 of this paper, is whether adverse habitat modification includes modifying or polluting the ocean “upstream” of the designated habitat substrate.

[31] See 44 Fed. Reg. 17710 (Mar. 23, 1979); 75 Fed. Reg. 319 (Jan. 5, 2010). The proposed turtle habitat’s PCEs include avenues of passage free from permanent structures, as well as the presence of prey species such as jellyfish. 75 Fed. Reg. 319.  The agency considered and rejected the idea of including water quality as a PCE both because of a purported lack of data and because the prey species may adequately reflect water quality.  Id.

[32] § 424.12(b).

[33] Id.

[34] 73 Fed. Reg. 72210 (Nov. 26, 2008).

[35] 50 C.F.R. § 226.216(a)(emphasis mine).

[36] 73 Fed. Reg. at 72214; the Final Rule defines “substrate of suitable quality” as “consolidated hard substrate or dead coral skeleton that is free from fleshy or turf macroalgae cover and sediment cover”, further emphasizing the idea that the designated “substrate” does not include the water above it.

[37] 69 Fed. Reg. 53136 (Aug 31, 2004).  The proposed habitat for Orca also necessarily includes the water, as that species only occupies the water itself, and not the substrate; 74 Fed. Reg. 17131.

[38] 73 Fed. Reg. at 72214.

[39] Id.; the agency apparently did not respond to the comment’s temperature concern.

[40] The agency similarly avoided designating water quality as a PCE when proposing critical habitat for the leatherback turtle.  See 75 Fed. Reg. at 324.

[41] 66 Fed. Reg. 29046, 29048-49 (May 29, 2001).

[42] 74 Fed. Reg. 1937, 1945 (Jan. 14, 2009).

[43] Compare 66 FR 29046, 29047 (white abalone larval period 5 to 14 days) with R. Ritson-Williams, Valerie J. Paul, S.N. Arnold, and R.S. Steneck, Larval settlement preferences and post-settlement survival of the threatened Caribbean corals Acropora palmata and A. cervicornis, 29 Coral Reefs 71, 71 (2010)(corals competent to metamorphose at 5 and 7 days).

[44] 75 Fed. Reg. 59900 (Sept. 28, 2010).

[45] See 75 Fed. Reg. 3711; note 36 above.

[46] See Cape Hatteras, 344 F. Supp. 2d 108 at 125 (noting “[d]esignationof unoccupiedland is a more extraordinary event that designation of occupied lands.”)

[47] See, e.g., Ryan P. Kelly and Stephen R. Palumbi, Genetic Structure Among 50 Species of the Northeastern Pacific Rocky Intertidal Community, 5 PLoS One, e8594, available at http://www.plosone.org (analyzing the different levels of population connectivity among species with different life history traits.)

[48] This framework ties easily into the modeling and monitoring efforts discussed supra in the context of take and jeopardy analyses.

[49] If high densities were required for critical habitat, surely the vast majority of listed species, including the California Condor and the Northern Spotted Owl, would lack designated critical habitat.

[50] 70 Fed. Reg. 52630, 52684 (September 2, 2005)(designating habitat for salmon and steelhead in western states; these species generally occupy the rivers and streams designated as critical habitat while they are larvae or juveniles, and again to reproduce as adults)(emphasis mine).  See also the Primary Constituent Elements for Gulf Sturgeon, 50 CFR § 226.214, which explicitly include requirements for eggs and larvae, as well as pathways for migration; § 226.211-212 do the same for various other listed salmon.  Other highly migratory species, such as Right whales, various sea turtles, and birds including Steller’s eider, similarly only occupy particular habitat seasonally.

[51] 50 C.F.R. § 424.02(d); § 424.12(b).

[52] 50 CFR § 424.12(b).

[53] 50 C.F.R. § 424.12(c).

[54] Cape Hatteras Access Preservation Alliance v. U.S. Dept. of Interior, 344 F.Supp.2d 108, 126 (D.D.C. 2004)(holding that FWS was reasonable in using “movable yet long-lasting lines, such as the [mean lower low-water] and vegetation lines” as boundaries for piping plover habitat, and noting “‘ephemeral’ appears to be unconcerned with whether the ephemeral thing moves or is fixed in place, but whether the thing exists for a long or short period of time.”)

[55] Note that a District court struck down a ‘zonal’ approach to designated critical habitat, Greenpeace v. NMFS, 237 F.Supp.2d 1181, 1199 (W.D. Wash. 2002), because the zones were not rationally related to the data presented.  In that case the zones were defined on the basis of conservation value rather than being defined temporally.

[56] Through the section 7 consultation process, see part 4 below.