Endangered and Threatened Wildlife and Plants; Endangered Species Status for Black Creek Crayfish and Designation of Critical Habitat

SUPPLEMENTARY INFORMATION:

Executive Summary

Why we need to publish a rule. Under the Act (16 U.S.C. 1531 et seq.), a species warrants listing if it meets the definition of an endangered species (in danger of extinction throughout all or a significant portion of its range) or a threatened species (likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range). If we determine that a species warrants listing, we must list the species promptly and designate the species' critical habitat to the maximum extent prudent and determinable. We have determined that the Black Creek crayfish meets the definition of an endangered species; therefore, we are proposing to list it as such and proposing a designation of its critical habitat. Both listing a species as an endangered or threatened species and making a critical habitat designation can be completed only by issuing a rule through the Administrative Procedure Act rulemaking process (5 U.S.C. 551 et seq.).

What this document does. We propose to list the Black Creek crayfish as an endangered species under the Act, and we propose to designate critical habitat for the species.

The basis for our action. Under the Act, we may determine that a species is an endangered or threatened species because of any of five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing regulatory mechanisms; or (E) other natural or manmade factors affecting its continued existence. We have determined that the Black Creek crayfish is endangered primarily due to the invasion of the white tubercled crayfish ( Procambarus spiculifer) through competition for food and shelter, and possibly through direct predation (Factors C and E).

Section 4(a)(3) of the Act requires that the Secretary of the Interior (Secretary), to the maximum extent prudent and determinable, designate critical habitat for the species concurrently with listing the species. Section 3(5)(A) of the Act defines critical habitat as (i) the specific areas within the geographical area occupied by the species, at the time it is listed, on which are found those physical or biological features (I) essential to the conservation of the species and (II) which may require special management considerations or protection; and (ii) specific areas outside the geographical area occupied by the species at the time it is listed, upon a determination by the Secretary that such areas are essential for the conservation of the species. Section 4(b)(2) of the Act states that the Secretary must make the designation on the basis of the best scientific data available and after taking into consideration the economic impact, the impact on national security, and any other relevant impacts of specifying any particular area as critical habitat.

Information Requested

We intend that any final action resulting from this proposed rule will be based on the best scientific and commercial data available and be as accurate and as effective as possible. Therefore, we request comments or information from other governmental agencies, Native American Tribes, the scientific community, industry, or any other interested parties concerning this proposed rule. We particularly seek comments concerning:

(1) The species' biology, range, and population trends, including:

(a) Biological or ecological requirements of the species, including habitat requirements for feeding, breeding, and sheltering;

(b) Genetics and taxonomy;

(c) Historical and current range, including distribution patterns and the locations of any additional populations of this species;

(d) Historical and current population levels, and current and projected trends; and

(e) Past and ongoing conservation measures for the species, its habitat, or both.

(2) Threats and conservation actions affecting the species, including:

(a) Factors that may be affecting the continued existence of the species, which may include habitat modification or destruction, overutilization, disease, predation, the inadequacy of existing regulatory mechanisms, or other natural or manmade factors;

(b) Biological, commercial trade, or other relevant data concerning any threats (or lack thereof) to this species; and

(c) Existing regulations or conservation actions that may be addressing threats to this species.

(3) Additional information concerning the historical and current status of this species.

(4) Specific information on:

(a) The amount and distribution of Black Creek crayfish habitat;

(b) Any additional areas occurring within the range of the species in the Lower St. Johns River Basin in Clay, Duval, Putnam, and St. Johns Counties in northeastern Florida that should be included in the designation because they (i) are occupied at the time of listing and contain the physical or biological features that are essential to the conservation of the species and that may require special management considerations or protection, or (ii) are unoccupied at the time of listing and are essential for the conservation of the species;

(c) Special management considerations or protection that may be needed in critical habitat areas we are proposing, including managing for the potential effects of climate change; and

(d) Whether areas not occupied at the time of listing qualify as habitat for the species and are essential for the conservation of the species.

(5) Land use designations and current or planned activities in the subject areas and their possible impacts on proposed critical habitat.

(6) Any probable economic, national security, or other relevant impacts of designating any area that may be included in the final designation, and the related benefits of including or excluding specific areas.

(7) Information on the extent to which the description of probable economic impacts in the economic analysis is a reasonable estimate of the likely economic impacts and any additional information regarding probable economic impacts that we should consider.

(8) Whether any specific areas we are proposing for critical habitat designation should be considered for exclusion under section 4(b)(2) of the Act, and whether the benefits of potentially excluding any specific area outweigh the benefits of including that area under section 4(b)(2) of the Act. If you think we should exclude any additional areas, please provide information supporting a benefit of exclusion.

(9) Whether we could improve or modify our approach to designating critical habitat in any way to provide for greater public participation and understanding, or to better accommodate public concerns and comments.

Please include sufficient information with your submission (such as scientific journal articles or other publications) to allow us to verify any scientific or commercial information you include.

Please note that submissions merely stating support for, or opposition to, the action under consideration without providing supporting information, although noted, do not provide substantial information necessary to support a determination. Section 4(b)(1)(A) of the Act directs that determinations as to whether any species is an endangered or a threatened species must be made solely on the basis of the best scientific and commercial data available, and section 4(b)(2) of the Act directs that the Secretary shall designate critical habitat on the basis of the best scientific data available.

You may submit your comments and materials concerning this proposed rule by one of the methods listed in ADDRESSES . We request that you send comments only by the methods described in ADDRESSES .

If you submit information via https://www.regulations.gov, your entire submission—including any personal identifying information—will be posted on the website. If your submission is made via a hardcopy that includes personal identifying information, you may request at the top of your document that we withhold this information from public review. However, we cannot guarantee that we will be able to do so. We will post all hardcopy submissions on https://www.regulations.gov .

Comments and materials we receive, as well as supporting documentation we used in preparing this proposed rule, will be available for public inspection on https://www.regulations.gov .

Our final determinations may differ from this proposal because we will consider all comments we receive during the comment period as well as any information that may become available after this proposal. Based on the new information we receive (and, if relevant, any comments on that new information), we may conclude that the species is threatened instead of endangered, or we may conclude that the species does not warrant listing as either an endangered species or a threatened species. For critical habitat, our final designation may not include all areas proposed, may include some additional areas that meet the definition of critical habitat, or may exclude some areas if we find the benefits of exclusion outweigh the benefits of inclusion and exclusion will not result in the extinction of the species. In our final rule, we will clearly explain our rationale and the basis for our final decisions, including why we made changes, if any, that differ from this proposal.

Public Hearing

Section 4(b)(5) of the Act provides for a public hearing on this proposal, if requested. Requests must be received by the date specified in DATES . Such requests must be sent to the address shown in FOR FURTHER INFORMATION CONTACT . We will schedule a public hearing on this proposal, if requested, and announce the date, time, and place of the hearing, as well as how to obtain reasonable accommodations, in the Federal Register and local newspapers at least 15 days before the hearing. We may hold the public hearing in person or virtually via webinar. We will announce any public hearing on our website, in addition to the Federal Register . The use of virtual public hearings is consistent with our regulations at 50 CFR 424.16(c)(3).

Previous Federal Actions

For a detailed description of Federal actions concerning the Black Creek crayfish that occurred prior to September 2021, please refer to the document we published in the Federal Register on September 29, 2021 (86 FR 53933).

On November 20, 2023, the Center for Biological Diversity (Center) sent the Service a notice of intent to sue, alleging violations of the Act and Administrative Procedure Act by denying protections to the Black Creek crayfish. The Center filed a complaint on February 16, 2024 ( Center v. Service, No. 1:24-cv-00457 (D.D.C.)). In May 2024, the court granted a stay in the case through August 30, 2024, to allow the Service to consider new information on the Black Creek crayfish and issue a new status determination. However, we are effectively mooting the action by publishing this proposed rule, which proposes to list the Black Creek crayfish as an endangered species, and proposes to designate critical habitat for the species, under the Act.

Peer Review

A species status assessment (SSA) team prepared an SSA report for the Black Creek crayfish. The SSA team was composed of Service biologists, in consultation with other species experts. The SSA report represents a compilation of the best scientific and commercial data available concerning the status of the species, including the impacts of past, present, and future factors (both negative and beneficial) affecting the species.

In accordance with our joint policy on peer review published in the Federal Register on July 1, 1994 (59 FR 34270), and our August 22, 2016, memorandum updating and clarifying the role of peer review in listing and recovery actions under the Act, we solicited independent scientific review of the information contained in the Black Creek crayfish SSA report (version 2.0). We sent the SSA report to six independent peer reviewers and received four responses. Results of this structured peer review process can be found at https://www.regulations.gov. In preparing this proposed rule, we incorporated the results of these reviews, as appropriate, into the SSA report, which is the foundation for this proposed rule.

Summary of Peer Reviewer Comments

As discussed in Peer Review above, we received comments from four peer reviewers on the draft SSA report. We reviewed all comments received from the peer reviewers for substantive issues and new information regarding the contents of the SSA report. The peer reviewers generally concurred with our methods and conclusions, and provided additional information, clarifications, and suggestions, including clarifications in using terminology and other editorial suggestions. All comments regarding Black Creek crayfish survey records were further clarified in the SSA report. Otherwise, no substantive changes to our analysis and conclusions in the SSA report were deemed necessary, and peer reviewer comments are addressed in version 2.0 of the SSA report (Service 2024, entire).

I. Proposed Listing Determination

Background

A thorough review of the taxonomy, life history, and ecology of the Black Creek crayfish is presented in the SSA report (version 2.0, Service 2024, pp. 9-16).

The Black Creek crayfish is endemic to the Lower St. Johns River Basin in four northeastern Florida counties (Clay, Duval, Putnam, and St. Johns). This small to medium-sized crayfish has dark claws and a dark carapace with a white or yellowish mid-dorsal stripe, white spots or streaks on its sides, and a rust-colored abdomen. The Black Creek crayfish lives for approximately 16 months and reproduces once during its life cycle. The Black Creek crayfish occurs in flowing, sand-bottomed, tannic-stained streams that contain cool, clean water, and maintain a constant flow of highly oxygenated water (greater than 5 parts per million). Within these streams, Black Creek crayfish require aquatic vegetation and debris for shelter, with alternating shaded and open canopy cover where they eat aquatic plants, dead plant and animal material, and detritus.

When version 1.0 of the SSA report was completed in 2019, the effects of the co-occurring white tubercled crayfish were uncertain, but it is now known that wherever white tubercled crayfish is found, it displaces Black Creek crayfish through competition or predation. Monitoring surveys in 2019-2023 documented expansion of the white tubercled crayfish, with 47 percent of the Black Creek crayfish's range facing inevitable extirpation due to white tubercled crayfish invasion, and 42 percent of the range at high risk of imminent invasion. The expansion of white tubercled crayfish and its apparent displacement of Black Creek crayfish led the Service to reassess the species in 2024. The Service updated the SSA report, resulting in version 2.0, and subjected the SSA report to peer review. As noted above, the Service considered peer review comments on the updated SSA report. The Service used the updated SSA report to make a new status determination for the Black Creek crayfish, resulting in this proposed rule.

Regulatory and Analytical Framework

Regulatory Framework

Section 4 of the Act (16 U.S.C. 1533) and the implementing regulations in title 50 of the Code of Federal Regulations set forth the procedures for determining whether a species is an endangered species or a threatened species, issuing protective regulations for threatened species, and designating critical habitat for endangered and threatened species. On April 5, 2024, jointly with the National Marine Fisheries Service, we issued a final rule that revised the regulations in 50 CFR part 424 regarding how we add, remove, and reclassify endangered and threatened species and what criteria we apply when designating listed species' critical habitat (89 FR 24300). On the same day, we published a final rule revising our protections for endangered species and threatened species at 50 CFR part 17 (89 FR 23919). These final rules are now in effect and are incorporated into the current regulations.

The Act defines an “endangered species” as a species that is in danger of extinction throughout all or a significant portion of its range, and a “threatened species” as a species that is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range. The Act requires that we determine whether any species is an endangered species or a threatened species because of any of the following factors:

(A) The present or threatened destruction, modification, or curtailment of its habitat or range;

(B) Overutilization for commercial, recreational, scientific, or educational purposes;

(C) Disease or predation;

(D) The inadequacy of existing regulatory mechanisms; or

(E) Other natural or manmade factors affecting its continued existence.

These factors represent broad categories of natural or human-caused actions or conditions that could have an effect on a species' continued existence. In evaluating these actions and conditions, we look for those that may have a negative effect on individuals of the species, as well as other actions or conditions that may ameliorate any negative effects or may have positive effects.

We use the term “threat” to refer in general to actions or conditions that are known to or are reasonably likely to negatively affect individuals of a species. The term “threat” includes actions or conditions that have a direct impact on individuals (direct impacts), as well as those that affect individuals through alteration of their habitat or required resources (stressors). The term “threat” may encompass—either together or separately—the source of the action or condition or the action or condition itself.

However, the mere identification of any threat(s) does not necessarily mean that the species meets the statutory definition of an “endangered species” or a “threatened species.” In determining whether a species meets either definition, we must evaluate all identified threats by considering the species' expected response and the effects of the threats—in light of those actions and conditions that will ameliorate the threats—on an individual, population, and species level. We evaluate each threat and its expected effects on the species, then analyze the cumulative effect of all of the threats on the species as a whole. We also consider the cumulative effect of the threats in light of those actions and conditions that will have positive effects on the species, such as any existing regulatory mechanisms or conservation efforts. The Secretary determines whether the species meets the definition of an “endangered species” or a “threatened species” only after conducting this cumulative analysis and describing the expected effect on the species.

The Act does not define the term “foreseeable future,” which appears in the statutory definition of “threatened species.” Our implementing regulations at 50 CFR 424.11(d) set forth a framework for evaluating the foreseeable future on a case-by-case basis which is further described in the 2009 Memorandum Opinion on the foreseeable future from the Department of the Interior, Office of the Solicitor (M-37021, January 16, 2009; “M-Opinion,” available online at https://www.doi.gov/sites/doi.opengov.ibmcloud.com/files/uploads/M-37021.pdf ). The foreseeable future extends as far into the future as the U.S. Fish and Wildlife Service and National Marine Fisheries Service (hereafter, the Services) can make reasonably reliable predictions about the threats to the species and the species' responses to those threats. We need not identify the foreseeable future in terms of a specific period of time. We will describe the foreseeable future on a case-by-case basis, using the best available data and taking into account considerations such as the species' life-history characteristics, threat-projection timeframes, and environmental variability. In other words, the foreseeable future is the period of time over which we can make reasonably reliable predictions. “Reliable” does not mean “certain”; it means sufficient to provide a reasonable degree of confidence in the prediction, in light of the conservation purposes of the Act.

Analytical Framework

The SSA report documents the results of our comprehensive biological review of the best scientific and commercial data regarding the status of the species, including an assessment of the potential threats to the species. The SSA report does not represent our decision on whether the species should be proposed for listing as an endangered or threatened species under the Act. However, it does provide the scientific basis that informs our regulatory decisions, which involve the further application of standards within the Act and its implementing regulations and policies.

To assess the Black Creek crayfish's viability, we used the three conservation biology principles of resiliency, redundancy, and representation (Shaffer and Stein 2000, pp. 306-310). Briefly, resiliency is the ability of the species to withstand environmental and demographic stochasticity (for example, wet or dry, warm or cold years); redundancy is the ability of the species to withstand catastrophic events (for example, droughts, large pollution events); and representation is the ability of the species to adapt to both near-term and long-term changes in its physical and biological environment (for example, climate conditions, pathogens). In general, species viability will increase with increases in resiliency, redundancy, and representation (Smith et al. 2018, p. 306). Using these principles, we identified the species' ecological requirements for survival and reproduction at the individual, population, and species levels, and described the beneficial and risk factors influencing the species' viability.

The SSA process can be categorized into three sequential stages. During the first stage, we evaluated the individual species' life-history needs. The next stage involved an assessment of the historical and current condition of the species' demographics and habitat characteristics, including an explanation of how the species arrived at its current condition. The final stage of the SSA involved making predictions about the species' responses to positive and negative environmental and anthropogenic influences. Throughout all of these stages, we used the best available information to characterize viability as the ability of a species to sustain populations in the wild over time, which we then used to inform our regulatory decision.

The following is a summary of the key results and conclusions from version 2.0 of the SSA report; the full SSA report can be found at Docket No. FWS-R4-ES-2024-0090 on https://www.regulations.gov .

Summary of Biological Status and Threats

In this discussion, we review the biological condition of the species and its resource needs, and the threats that influence the species' current and future condition, in order to assess the species' overall viability.

At an individual level, Black Creek crayfish require aquatic vegetation, leaf litter, and tree roots or undercut banks for shelter, as well as aquatic plants, dead plant and animal material, and detritus for food. Additionally, individuals need clean and cool, highly oxygenated, flowing water to survive. For populations of Black Creek crayfish to persist, the needs of individuals (suitable shelter, food sources, mates) must be met at a larger scale. Connected areas of habitat must be large enough to support a reservoir of potential mates for breeding and to avoid inbreeding depression. For Black Creek crayfish, suitable habitat depends on the absence of competitors ( e.g., white tubercled crayfish) and maintenance of sand-bottomed, highly oxygenated, tannic headwater streams.

Species viability requires adequate redundancy. Redundancy is sustained by resilient populations (natural or reintroduced) distributed across the species' range, and connectivity allows nearby populations to expand their range, rescue and recolonize areas after catastrophic events, or both. Representation can be maintained through heterogeneity of occupied habitats and sustained resilient populations spread across the range of genetic and/or ecological diversity for the species. The Black Creek crayfish occupies similar habitat (primarily high-quality headwater streams) throughout its range. Long-term viability requires resilient populations to be sustained into the future. For this species, long-term viability means protecting and maintaining high-quality headwater streams and excluding or minimizing impacts from nonindigenous and invading competitors.

Influences on Black Creek crayfish viability vary by location, but the most imminent threat to the species is competition and potential predation from the nonindigenous and invading white tubercled crayfish (Factors C and E), which is now being regularly detected across the Black Creek crayfish's range in addition to other crayfish competitors. Other threats include disease (Factor C), habitat degradation and water quality impairment (Factor A), and a changing climate (Factor E) and are described in more detail in the SSA report (Service 2024, pp. 18-39).

White Tubercled Crayfish

The white tubercled crayfish, a crayfish from an adjacent watershed, was introduced to the Black Creek crayfish's range and is influencing Black Creek crayfish through competition for food and shelter and possibly through direct predation (Service 2024, pp. 18-25). The white tubercled crayfish is native to the United States and is broadly distributed across the Southeast. In Florida, white tubercled crayfish historically only occurred in the St. Mary's and Suwannee basins in the northern part of the State, as well as in panhandle basins (NatureServe 2023, unpaginated). The first detection of white tubercled crayfish in areas known to be historically occupied by Black Creek crayfish was in 2008 (Franz et al. 2008, p. 16). While it is unclear if the white tubercled crayfish expanded its range in Florida from the north and west, Trail Ridge, a sandy dune geologic feature running north to south from South Georgia through North Florida, was likely a barrier to white tubercled crayfish expansion (G. Warren 2020, pers. comm.; U.S. Geological Survey (USGS) 1989, entire).

Analysis of the pattern of white tubercled crayfish and Black Creek crayfish presence/absences suggests that the white tubercled crayfish was introduced into the Black Creek Basin rather than spreading naturally from the north (Fralick et al. 2021, p. 18). One explanation for introduction is through live bait release from fishing, which is one of the main methods for crayfish invasions (DiStefano et al. 2015, p. 404). Other mechanisms for introductions include personal aquarium releases, planting of infested aquatic plants, intentional stocking, and the potential release of crayfish for educational purposes (Nagy et al. 2022, unpaginated; Donahou et al. 2024, unpaginated). Commercial sales of white tubercled crayfish are legal in Florida. The first record of white tubercled crayfish in the Black Creek Basin was in an urbanized portion of Bull Creek in the Lower South Fork of Black Creek subwatershed that is located near the center of the Black Creek Basin (Franz et al. 2008, p. 17).

From 2012-2018, the white tubercled crayfish was detected at two sites in the Black Creek Basin. A 2021 basin-wide evaluation of the population status of Black Creek crayfish comparing 2018-2023 surveys with sites historically occupied by Black Creek Crayfish between 1976-2016 indicated a substantial decline in Black Creek crayfish occurrences and a corresponding increase in the number of sites inhabited by white tubercled crayfish (Fralick et al. 2023, unpublished data). Surveys from 2018-2023 across 75 sites historically occupied by Black Creek crayfish documented 51 total sites (68 percent) occupied by white tubercled crayfish, 33 of which (44 percent) it has replaced Black Creek crayfish. Black Creek crayfish occurrence was reduced to only 36 (48 percent) of the 75 historical sites; however, white tubercled crayfish has been detected in 18 of these sites, leaving only 18 (24 percent) of the historical sites unoccupied by white tubercled crayfish. While we do not have a rate of extirpation calculated, the replacement of Black Creek crayfish by white tubercled crayfish has been dramatic since its initial detection in 2008. Given these recent trends, the 18 sites with both Black Creek crayfish and white tubercled crayfish present will likely transition to only white tubercled crayfish occupation in the future.

Some barriers, such as natural or artificial waterfalls, culverts, or salinity, seem to prevent or at least slow down the spread of white tubercled crayfish (Reisinger et al. 2023, p. 2). Within the Black Creek Basin, all the Black Creek crayfish sites where white tubercled crayfish have not been found are in the headwaters behind barriers or in Peter's Creek, a tributary near Black Creek's terminus where it meets the brackish St. Johns River. The remainder of the Black Creek crayfish sites with no white tubercled crayfish present are located outside of the Black Creek basin or are on the east side of the St. Johns River.

Preliminary data suggest that the white tubercled crayfish tolerates a wider range of stream temperatures than the Black Creek crayfish (Warren et al. 2019, pp. 8-9). Both crayfish species require high dissolved oxygen levels and generally overlap in many aspects of their resource needs. White tubercled crayfish reach a larger size than Black Creek crayfish, have a higher growth rate, and outcompete Black Creek crayfish when they have a size advantage (Reisinger et al. 2023, p. 12). White tubercled crayfish likely have a size advantage over Black Creek crayfish during much of the lifecycle due to higher growth rates and culmination in a larger overall maximum size (Reisinger et al. 2023, p. 11). In an enclosure experiment, there were no observed impacts of white tubercled crayfish on the growth or survival of Black Creek crayfish, but Black Creek crayfish used the shelter less frequently in the presence of white tubercled crayfish (Reisinger et al. 2023, pp. 11-12) This suggests that competition for shelter may be a key mechanism by which the white tubercled crayfish is replacing the Black Creek crayfish (Reisinger et al. 2023, p. 12). Several other studies have found that introduced crayfish can outcompete native crayfish for shelter and lead to displacement (Hill and Lodge 1994, entire; Usio et al. 2001, entire; Chucholl et al. 2008, entire).

Additional research is needed to fully understand the life histories and resource needs for both species, the extent of their interspecific competition for resources, and their behavioral ecology. It is theorized that white tubercled crayfish may have an advantage over Black Creek crayfish because they have a longer lifespan and likely reproduce multiple times over a lifetime, whereas female Black Creek crayfish only reproduce once during their life cycle (Franz 1994, p. 212; Hightower and Bechler 2013, pp. 86-87). Although not yet documented for Black Creek crayfish and white tubercled crayfish interactions, reproductive interference is also a potential mechanism for species replacement (M. Ellis 2023, pers. comm.). In some systems, nonindigenous male crayfish have tried to mate with native females, producing no offspring, but effectively eliminating the female's reproductive capacity for the season (J. Cook 2023, pers. comm.; Butler and Stein 1985, p. 14; Ellis 1999, pp. 108-109). It is also possible that changing environmental factors are enhancing the white tubercled crayfish's ability to move into and dominate areas once occupied by Black Creek crayfish. There is anecdotal evidence that after a severe drought, white tubercled crayfish recolonized rehydrated streams more rapidly than Black Creek crayfish (Smith-Hicks 2020, p. 1).

Overall, the white tubercled crayfish can be considered both a stochastic threat, depending on the timing of invasion and interaction with the Black Creek crayfish, and a catastrophic threat, because of the likelihood of human-mediated introduction as well as their ability to outcompete and displace the Black Creek crayfish, thus making the entire Black Creek crayfish species vulnerable to extirpation throughout its range.

Other Influencing Factors

There are several influences that individually and synergistically impact Black Creek crayfish viability. These include other crayfish competitors, disease, habitat degradation and water quality impairment, and climate change.

Other Crayfish Competitors

Other crayfish species, including both native and nonnative species, can pose a threat if they are aggressive, are resilient to more extreme conditions, or compete for food and cover, thus starving other crayfish species and forcing them out of refugia where other animals can more easily prey upon them. In addition to the nonindigenous and invading white tubercled crayfish ( Procambarus spiculifer), Black Creek crayfish are occasionally found with other native crayfish species, including slough crayfish ( P. fallax), peninsula crayfish ( P. paeninsulanus), brushpalm crayfish ( P. pubischelae), and Seminole crayfish ( P. seminolae), which may compete with them for resources (Franz 1994, p. 212; Franz et al. 2008, pp. 14, 16; Nelson and Floyd 2011, pp. 5-6). While not known to occur within the range of the Black Creek crayfish, there is a small, introduced population of highly aggressive and invading red swamp crayfish ( P. clarkii) in the Doctors Lake subwatershed, which borders the Black Creek Basin. This population is limited to a small retention pond and a few drainage ditches. Eradication efforts in 2022 were unsuccessful, as surveys in 2023 continued to find red swamp crayfish (Gestring 2023, pers. comm.).

Disease

Microsporidian diseases have been attributed to Black Creek crayfish declines (Reisinger et al. 2023, pp. 10-11; Service 2024, pp. 25-28). Microsporidia are spore-forming, obligate, intracellular parasites whose numerous hosts include crayfish. In crayfish, the disease usually causes the deterioration of muscle tissue, lethargy, and eventually death (Freeman et al. 2010, pp. 217-218), or can alter the habitat use or body condition and increase susceptibility to infection (Reisinger and Bolds 2022, p. 3). Visual signs of the disease are white streaks or white opaque abdominal tissue, lending to the name “porcelain disease” or “cotton tail,” that usually becomes more pronounced as the infection progresses. Black Creek crayfish with microsporidian disease have been reported in several studies (Franz et al. 2008, p. 13; Nelson and Floyd 2011, p. 6; Smith-Hicks 2020, p. 1;Reisinger et al. 2023, pp. 10-11).

Habitat Degradation and Water Quality Impairment

Within the range of the Black Creek crayfish, pollution from nonpoint sources stemming from urbanization, mining, and other activities has been documented in the past (Brody 1990, p. 21; Franz and Franz 1990, p. 294; Florida Natural Areas Inventory (FNAI) 2001, p. 2; Franz et al. 2008, pp. 17-18; Nelson and Floyd 2011, pp. 6-7). Not only can these impacts cause direct mortality to crayfish, but they can also degrade habitat used for foraging, sheltering, and spawning. Sections 4.3 and 4.4 of the SSA report provide additional details about the effects of water withdrawals and other development-related, mining, and agricultural/silvicultural activities that affect water quality within the Black Creek Basin (Service 2024, pp. 29-33). Implementation of construction, agricultural, and silvicultural best management practices (BMPs) has alleviated many past threats associated with siltation and other water quality impacts in recent years and have improved overall habitat conditions within the Black Creek crayfish's range (Service et al. 2017, p.24; Florida Department of Agriculture and Consumer Services (FDACS) and Florida Fish and Wildlife Conservation Commission (FWC) 2018, p. 4;).

Climate Change

Effects of climate change, such as increasing temperatures, increased catastrophic storm and/or extreme drought events, and sea level rise, pose ongoing risks to habitat suitability for the Black Creek crayfish. The climate in the southeastern United States has warmed approximately 1 degree Celsius (°C) (approximately 2 degrees Fahrenheit (°F)) since the 1970s and is expected to continue to rise (Carter et al. 2014, pp. 398-399; Carter et al. 2018, pp. 749-750). Various emissions scenarios suggest that, by the end of the 21st century, average global temperatures are expected to increase 2 to >4 °C (3.6 to >7.2 °F) (Intergovernmental Panel on Climate Change (IPCC) 2022, entire). By the end of 2100, it is extremely likely that there will be more frequent hot and fewer cold temperature extremes over most land areas on daily and seasonal timescales, and it is very likely that heat waves and extreme precipitation events may occur with higher frequency and intensity (IPCC 2014, pp. 15-16; Carter et al. 2018, pp. 750-752).

Projections for future precipitation trends in the Southeast are less certain than those for temperature, but suggest that overall annual precipitation may decrease, and that tropical storms may occur less frequently, but with more force (more category 4 and 5 hurricanes) than historical averages (Carter et al. 2014, p. 398). Projected warmer temperatures and decreased precipitation may increase water temperatures and concurrently decrease dissolved oxygen levels; change runoff regimes; and increase frequency, duration, and intensity of droughts in the southeastern United States (Carter et al. 2018, pp. 746, 773, 775). Droughts cause decreases in water flow and dissolved oxygen levels and increases in temperature in stream systems; droughts can also lead to increases in the concentration of pollutants. These issues may be exacerbated by increases in groundwater withdrawals that likely coincide with human population increases.

The restricted range of the Black Creek crayfish may indicate a narrow tolerance for temperature increases resulting from climate change in northeastern Florida. The direct influence of temperature changes to crayfish habitat depends on the species' thermal range, geographical distribution, and general ability to acclimate (Carmona-Osalde et al. 2003, p. 306). Previous research indicates increased temperature can lead to decreased survival, growth rates, and reproduction (Carmona-Osalde et al. 2003, pp. 308-313), as well as behavioral modifications (Seals et al. 1997, pp. 136-137) in other Procambarus species. There are no direct studies to indicate the impact higher water temperatures would have on Black Creek crayfish populations; however, there are some early indications that Black Creek crayfish are disappearing from previously occupied streams, and congeners such as slough crayfish, peninsula crayfish, and Seminole crayfish are replacing them in streams above 31°C (88 °F) and with dissolved oxygen levels below 4 milligrams per liter (mg/L) (Fralick et al. 2021, p. 16).

Sea level rise may cause saltwater intrusion of groundwater within the range of the Black Creek crayfish, increasing salinity and decreasing oxygen levels, even in areas not directly impacted by higher tide levels and inundation. Prior to surface inundation, habitat may undergo vegetation shifts triggered by changes to hydrology (wetter), salinity (higher), and more frequent storm surge and king tide events (pulse events causing massive erosion and salinization of soils) (Saha et al. 2011, pp. 181-182).

Conservation Efforts and Regulatory Mechanisms

Habitat Protection and Management

In 2013, the Florida Natural Areas Inventory (FNAI) indicated that 40 percent of Black Creek crayfish habitat was protected (FNAI 2013, p. D-7). The range of the Black Creek crayfish largely overlaps public lands managed by the Florida Army National Guard (Camp Blanding Joint Training Center (Camp Blanding)), St. Johns River Water Management District, and the Florida Forest Service, specifically three State forests: Belmore, Jennings, and Etoniah Creek (Service 2024, p. 37). Resource management activities occur on these public lands. Additional Black Creek crayfish are known to occur on mitigation bank parcels. Land managers of public conservation lands do not necessarily manage stream habitat or the fauna that live in streams, although these areas likely benefit from management of adjacent uplands. Black Creek crayfish populations on public lands may receive some protection, but no rangewide conservation actions have yet been undertaken for the species.

Florida statutes require managers of lands that contain imperiled species to consider the habitat needs of these species during preparation of management plans and require that all land management plans include short-term and long-term goals to serve as the basis for land management activities; these goals include measurable objectives for imperiled species habitat maintenance, enhancement, restoration, or population restoration (Florida Statutes, title XVIII, section 253.034(5)).

As part of the implementation of the Sikes Improvement Act (1997; 16 U.S.C. 670 et seq), the Secretaries of the military departments are required to prepare and implement an integrated natural resources management plan (INRMP) for each military installation in the United States. The INRMP must be prepared in cooperation with the Service and State fish and wildlife agencies and must reflect the mutual agreement of these parties concerning conservation, protection, and management of wildlife resources (16 U.S.C. 670a). The Department of Defense (DoD) must conserve and maintain native ecosystems, viable wildlife populations, Federal and State listed species, and habitats as vital elements of its natural resource management programs on military installations, to the extent that these requirements are consistent with the military mission (DoD Instruction 4715.3).

Camp Blanding, the property with the largest known occurrence of Black Creek crayfish, is owned by the State of Florida and managed by the Florida Army National Guard. In 2017, Camp Blanding entered into a 15-year candidate conservation agreement with assurances (CCAA) to protect Federal candidate and Florida Fish and Wildlife Conservation Commission (FWC) listed species, including Black Creek crayfish (Service et al. 2017, entire). Enrolled lands include 46,507 acres of the total 73,000-acre installation (Service et al. 2017, p. 2) and encompass 121 miles of streams, many of which are occupied by the Black Creek crayfish. Surveys have found white tubercled crayfish co-occurring with Black Creek crayfish in several locations; however, some headwaters are protected from white tubercled crayfish invasion by barriers. The objectives for the Camp Blanding CCAA are to: (1) maintain or enhance the quality of habitat for the covered species on the enrolled lands, (2) reduce or eliminate disease transmission to the covered species on the enrolled lands, and (3) reduce or eliminate exotic and invasive species on the enrolled lands. During the implementation of the CCAA, hydrologic measurements will be taken, and invasive (including nonindigenous and invading) species will be monitored in areas known to be occupied by Black Creek crayfish on Camp Blanding lands (Service et al. 2017, p. 24). Additionally, Black Creek crayfish will be surveyed at least once every 5 years to evaluate the success of conservation actions and implementation of BMPs for improved water quality, reduction and/or elimination of disease transmission, and control of exotic and invasive species (Service et al. 2017, p. 24). In addition to the CCAA and existing INRMP, Camp Blanding has an ongoing program to purchase lands within 3 miles of the installation to create a buffer for the localized effects of loud training exercises. These lands would not fall within the purview of the CCAA, and Black Creek crayfish habitat in streams surrounded by these lands would not be afforded the same protections as those that occur on the installation.

The Florida Department of Environmental Protection (DEP) coordinates development and implementation of basin management action plans (BMAPs) to assess, monitor, and improve the water quality of water bodies in the basin that are considered “impaired” by pollution. Total maximum daily loads (TMDLs) are water quality targets for specific pollutants (such as fecal coliforms) that are established for impaired waterbodies that do not meet their designated uses based on Florida water quality standards (DEP 2008, p. 1). A BMAP prepared for tributaries to the lower St. Johns River (DEP 2008, entire) addresses water quality issues for some drainages in or near the range of the Black Creek crayfish. Two streams in urbanizing areas, Big Davis Creek and Durbin Creek, in southeastern Duval and northwestern St. Johns Counties are locations where TDMLs were established (DEP 2008, p. 87), and subsequently were met so that they are no longer considered impaired waters and could provide habitat for Black Creek crayfish (FDEP 2022, entire).

State Conservation Measures

The Black Creek crayfish was listed by the State of Florida as a State threatened species in 2018 (FWC 2018, p. 8) and is afforded protections under Florida Administrative Code section 68A-27.003(2)(a), which makes it illegal to take, possess, or sell Black Creek crayfish except as authorized by permit from FWC. Florida Administrative Code section 68A-27.001(4) defines the term “take” for the purpose of this prohibition. Subsequently, FWC has also drafted Species Conservation Measures and Permitting Guidelines for the Black Creek crayfish (see Florida Administrative Code section 68A-27.003(2)(b)3 and FWC 2019, entire). Intentional take permits authorizing the take of State-designated threatened species are issued for scientific or conservation purposes that will benefit the survival potential of the species, as described in Florida Administrative Code section 68A-27.007(2)(a). Incidental take permits are issued when there is a scientific or conservation benefit and only after showing that the permitted activity will not negatively impact the species, as described in Florida Administrative Code section 68A-27.007(2)(b).

The FWC has also drafted a Species Action Plan (SAP; FWC 2013, entire) to guide conservation actions for the benefit of the Black Creek crayfish across its range. The Black Creek crayfish SAP details the actions deemed necessary to improve the species' conservation status, including: (1) working with land managers and landowners to protect, monitor, and enhance the habitat quality of known crayfish sites; (2) drafting and disseminating stream-centered habitat management recommendations to reduce threats and safeguard crayfish and riparian corridors; and (3) continuing to survey to determine the extent of occupied stream reaches and to identify additional occupied drainages to extend the known range of the species, decentralize its vulnerability to threats, and reduce its overall risk of extinction.

Forestry and Agriculture BMPs

To avoid activities that could degrade or alter riparian zones adjacent to areas inhabited by the Black Creek crayfish, as well as to prevent upland erosion into streams and rivers, some actions require measures to avoid take of the species. These include following guidelines for activities that do not require FWC permits, including avoidance of degradation of Black Creek crayfish habitat through the State of Florida BMPs for stormwater runoff and the FDACS silviculture BMPs. Modern forestry operations in Florida have a (self-reported) compliance rate of 100 percent for following Wildlife Best Management Practices (WBMPs) for State-imperiled species, including the Black Creek crayfish. Forestry protection of special management zones (SMZs) may reduce contribution of nonpoint source pollution (FDACS and FWC 2018, p. 4). SMZs are meant to provide shade for temperature regulation, a natural vegetation strip, intact ground cover, large and small woody debris, leaf litter, and a variety of tree species and age classes; most of these habitat components benefit Black Creek crayfish (FDACS 2014, p. 5). For the sites following WBMPs across the State of Florida in 2017, 19 percent were located on private nonindustrial forestlands, 64 percent on forest industry lands, and 17 percent on public lands (FDACS and FWC 2018, p. 4). According to Florida's BMPs for forestry, SMZs should be 35 ft wide (200 ft for Outstanding Florida Waters (OFWs)), but selective logging is permitted in this zone (FDACS 2008, p. 9).

Cumulative Effects

We note that, by using the SSA framework to guide our analysis of the scientific information documented in the SSA report, we have analyzed the cumulative effects of identified threats and conservation actions on the species. To assess the current and future condition of the species, we evaluate the effects of all the relevant factors that may be influencing the species, including threats and conservation efforts. Because the SSA framework considers not just the presence of the factors, but to what degree they collectively influence risk to the entire species, our assessment integrates the cumulative effects of the factors and replaces a standalone cumulative-effects analysis.

Current Condition

Black Creek crayfish analysis units were delineated using HUC 12 (12-digit hydrologic unit code) subwatersheds from the U.S. Geological Survey (USGS) Watershed Boundary Dataset (USGS 2024, unpaginated). There may be genetic separation of Black Creek crayfish on the east and west side of the St. Johns River based on limited samples (Breinholt and Crandall 2010, entire); therefore, we separated the Black Creek crayfish into two representation units: one on the east side of the St. Johns River and one on the west side of the St. Johns River. There are no meaningful ecological distinctions between these representation units. We identified 19 analysis units across the range of the Black Creek crayfish; three units are located in the eastern representation unit, and 16 units are located in the western representation unit (see figure 1, below).

Figure 1. Black Creek crayfish analysis units, defined by HUC 12 hydrologic units.

We assessed resiliency at the analysis unit (HUC 12 subwatershed) scale. Due to the local impact of white tubercled crayfish on Black Creek crayfish occupancy, units with only white tubercled crayfish present were assigned no resiliency and not evaluated further, as Black Creek crayfish in these watersheds are considered at high risk of extirpation, given recent evidence of rapid community replacement as detailed above. “No resiliency” is an indication of functional extirpation, as Black Creek crayfish have been documented in each analysis unit in the past 12 years (Fralick 2023, entire), but the rapid replacement by white tubercled crayfish currently nullifies any ability for the Black Creek crayfish to persist.