Alabama cavefish

Last updated

Alabama cavefish
AlabamaCavefish.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Percopsiformes
Family: Amblyopsidae
Genus: Speoplatyrhinus
J. E. Cooper & Kuehne, 1974
Species:
S. poulsoni
Binomial name
Speoplatyrhinus poulsoni
J. E. Cooper & Kuehne, 1974 [5]
Alabama Cavefish Range.png
The range of the Alabama cavefish

The Alabama cavefish (Speoplatyrhinus poulsoni) is a critically endangered species of amblyopsid cavefish found only in underground pools in Key Cave, located in northwestern Alabama, United States in the Key Cave National Wildlife Refuge. [6] It was discovered underneath a colony of gray bats in 1967 by researchers Robert A. Kuehne and John E. Cooper [7] and scientifically described in 1974. [8]

Contents

On any single visit to the cave, no more than 10 individuals of this fish have been observed, and scientists estimate fewer than 100 are left. [7] This species of fish is believed to be the rarest species of cavefish in the United States and one of the rarest of all freshwater fish, as researchers have failed to find the fish in any other location. [1] [7] The Alabama cavefish exists in a fragile ecosystem based on nutrient-rich guano of the gray bat. [9]

Little is known of the reproductive habits and life history of the Alabama cavefish. However, researchers agree that the flooding of the cave triggers a hormonal change in the cavefish, prompting the fish to begin the reproductive cycle. [10] Thus, variations in the frequency of the cave flooding negatively affect the survival of the species. [10]

Unfortunately, the Alabama cavefish is in danger of extinction, according to both the ESA and IUCN listings. [1] [11] Conservation measures that have been taken to save the species from extinction include protecting the fish under the Lacey Act and limiting human disturbance of Key Cave, the species' critical habitat. [7] [10]

Habitat and distribution

The Alabama cavefish is one of the rarest cavefish species in North America. [8] While the specific habitat requirements of the fish are unknown, it is known that the Alabama cavefish is a cave obligate, restricted to Key Cave in Lauderdale County, Alabama. [9] Key Cave is the critical habitat of the Alabama cavefish. [12] Cave habitats tend to be stable, with drastic changes mainly being associated with the inflow of water. [13] Annual rainfall and flooding in the cave produce changes in water level, temperature, and food availability for the fish. [13] Researchers speculate that the flooding may trigger a hormonal change in the cavefish for growth and reproduction. [13]

Since the discovery of the cavefish, only nine specimens have been collected (all before 1983). [12] Because very few individuals have been collected and observed, and the population is confined to Key Cave , the Alabama cavefish is believed to be the rarest of the American cavefish and the rarest of all freshwater fish. [7]

Since the underground water system in the area is so widespread, researchers had hoped that the cavefish had dispersed to other sites. [11] However, studies of the 120 other caves in the area, conducted since 1977, have failed to locate any other Alabama cavefish populations. [11] No more than 10 individuals have been observed on any single visit to the Key Cave, and in the 36 visits from 1967 to 1998, the average was less than 4 per visit. [1] The total number of individuals in the Key Cave population is estimated to be less than 100. [1] Initially classified as vulnerable by the IUCN, its status has been gradually upgraded as its extreme rarity became apparent. The Alabama cavefish is currently considered critically endangered by the IUCN. [1] Two reports of these fish in a nearby cave, Collier Cave, are still unconfirmed. [10] Both Key Cave and Collier Cave are protected and inaccessible to the public. [10]

Because its known range is limited to a single cave, the Alabama cavefish has an uncertain future, being threatened by changes in groundwater quality and level, changes in aquifer characteristics, and diminished organic input, as well as competition and predation. [9] [10] It also may compete for resources with the syntopic southern cavefish (Typhlichthys subterraneus), which is more abundant and aggressive. [9] Furthermore, cave crayfish feed on Alabama cavefish. [9]

Physiology

The Alabama cavefish is roughly 7.2 cm (2.8 in) in length and has no eyes or discernible pigmentation, appearing semitransparent with a slight pink hue. [6] Its large head makes up more than one-third of its length. [6] The Alabama cavefish is the only species in its genus and can be distinguished from other cavefish by its elongated, flattened head with a laterally constricted snout and a terminal mouth. [6] The Alabama cavefish lacks pelvic fins, and its fin rays are unbranched with the fin membranes deeply incised between the rays. [6] It has an elaborate system of sensory papillae arranged in ridges on the head and sides, an adaptation to the dark environment of the cave. [9] The Alabama cavefish has the most highly developed caudal sensory papillae in the family Amblyopsidae. [12]

Diet

The diet of the Alabama cavefish, which consists of copepods, isopods, amphipods, and smaller cavefish, is supported by the nutrient-filled bat guano. [9] It also can survive on other small organisms such as mites, spiders, millipedes, beetles, and other insects. [12]

Life history and reproduction

There is little information available on both the life history and reproductive cycle of the Alabama cavefish. It is hypothesized that, because of the jugular position of the vent and the size of the branchial chamber, the Alabama cavefish practices branchial incubation, or mouth-brooding. [7] The Alabama cavefish, like most fish, utilizes seasonal cues to trigger hormonal changes that lead to its growth and reproduction. [9] While most fish rely on a large change in water temperature or photoperiod, the Alabama cavefish mainly relies on the flooding of the cave in the winter and spring. [9] [10] This flooding results in an increased inflow of water into the cave and a small temperature change, signaling to the cavefish to begin reproduction. [10] Even with these cues, reproduction does not occur every year for the Alabama cavefish. [8] In years when reproduction does occur, only a few eggs are produced per female. [8] Assumptions about the life history of the Alabama cavefish are largely based on information from the Northern cavefish, which sees only about 20% of the females spawn in a given year. [12] It is hypothesized that the population growth for the Alabama cavefish is less than half of that of the Northern cavefish. [12] Furthermore, the maximum longevity of the Alabama cavefish is estimated to be around 5–10 years; however, this estimate could be off by a factor of 3 or 4. [12]

Listing history

Endangered Species Act

The Alabama cavefish was first listed as a threatened species under the Endangered Species Act in 1977. [3] [12] Following further assessment of the species' range and changing environmental conditions, the cavefish was considered an endangered species in 1988. [4] [12] By 1990, a recovery plan was created for the fish, which stipulates that the species would be down-listed when the following three criteria are met: (1) three other viable populations are found in discontinuous aquatic systems outside the Key Cave area, (2) the aquifer recharge areas for all four populations are protected, and (3) all four populations are demonstrated to be stable or increasing over at least a 20-year period. [12]

In 2019, amendments to the recovery plan were made that changed the criteria for down-listing and created a criterion for delisting. [11] For the cavefish to be down-listed, the criteria now stipulate that: (1) the species must demonstrate a stable or increasing trend in the existing Key Cave population, (2) two more cavefish populations must be created, and (3) the aquifer recharge areas must be delineated, mapped, and protected. [11] In order for the cavefish to be delisted entirely, however, the aquifer recharge area must be protected by a conservation mechanism for at least one of the new populations and all other threats to the cavefish must be addressed or managed, allowing viability for the foreseeable future. [11]

International Union for Conservation of Nature Red List

The Alabama cavefish was first listed on the IUCN Red List of Threatened Species in 1986 as vulnerable and remained in that category following re-evaluation in 1988. [1] Two years later, in 1990, the status of the cavefish was reassessed and upgraded to endangered, which was then again confirmed by a reassessment in 1994. [1] In 1996, the Alabama cavefish was again upgraded to critically endangered due to its lack of extent (100 sq. km), low population size, and numerous habitat challenges. [1] The species was last assessed in April 2012, and although its population trend is stable, it is still listed as critically endangered. [1]

Conservation

There are a few current conservation measures put in place to protect the Alabama cavefish. Along with being listed under the ESA, the species is protected by the Lacey Act. [7] This makes it unlawful to import, export, transport, sell, receive, acquire, or purchase (alive or dead, including parts, products, eggs, or offspring) the Alabama cavefish. [7] Secondly, The Tennessee Valley Authority, which owns the two entrances to the caves, has installed a fence to limit human disturbance. [7] Lastly, in 1997, the Key Cave National Wildlife Refuge (NWR) was established. [14] The Key Cave NWR aims at ensuring the biological integrity of the cave by protecting the sinkholes that carry surface water directly into the aquifer of the cave. [14]  

Human impact

The largest human-induced threat to the survival of the Alabama cavefish is groundwater contamination within the recharge area of Key Cave. [10] The recharge area is the place where water seeps into the ground and refills the aquifer. [10] A major source of contamination is the chemicals used to cultivate crops grown in the areas surrounding the cave. [10] Furthermore, the collection of the species by amateurs or for scientific purposes poses a major threat due to the already small population size. [7]

Factors likely to cause extinction

Many factors that are likely to cause the extinction of the Alabama cavefish are associated with the recharge zone of the Key Cave. [10] The degradation of the groundwater due to agrochemicals and the decreasing level of groundwater limit the entry and cycling of uncontaminated water into Key Cave. [7] The alteration of flood cycles within the aquifer often leads to unsuccessful cavefish reproduction. [14] [10] Furthermore, the Gray bat, Myotis grisescens, which is also protected under the ESA, provides nutrients to the Alabama cavefish through its guano. [7] Therefore, the threats facing this bat species also impact the Alabama cavefish and its fuel source. [7] All of these factors, combined with the already small population size and limited home range, pose severe threats to the Alabama cavefish. [7]

Related Research Articles

The northern cavefish or northern blindfish is found in caves through Kentucky and southern Indiana. The International Union for Conservation of Nature lists the species as near threatened.

<span class="mw-page-title-main">Amblyopsidae</span> Family of fishes

The Amblyopsidae are a fish family commonly referred to as cavefish, blindfish, or swampfish. They are small freshwater fish found in the dark environments of caves, springs and swamps in the eastern half of the United States. Like other troglobites, most amblyopsids exhibit adaptations to these dark environments, including the lack of functional eyes and the absence of pigmentation. More than 200 species of cavefishes are known, but only six of these are in the family Amblyopsidae. One of these, Forbesichthys agassizii, spends time both underground and aboveground. A seventh species in this family, Chologaster cornuta, is not a cave-dweller but lives in aboveground swamps.

<span class="mw-page-title-main">Gray bat</span> Species of mammal

The gray bat is a species of microbat endemic to North America. It once flourished in caves all over the southeastern United States, but due to human disturbance, gray bat populations declined severely during the early and mid portion of the 20th century. 95% of gray bats now hibernate in only 15 caves. M. grisescens has been listed as federally endangered by the U.S. Fish and Wildlife Service since 1976, and is protected under the Endangered Species Act. Gray bat populations were estimated at approximately 2 million bats around the time they were placed on the Endangered Species list. By the early 1980s populations of gray bats dropped to 1.6 million. With conservation efforts in place, in 2004, gray bat populations were estimated to have reached 3.4 million.

<span class="mw-page-title-main">Kentucky cave shrimp</span> Species of crustacean

The Kentucky cave shrimp is an eyeless, troglobite shrimp. It lives in caves in Barren County, Edmonson County, Hart County and Warren County, Kentucky. The shrimp's shell has no pigment; the species is nearly transparent and closely resembles its nearest relative, the Alabama cave shrimp.

<span class="mw-page-title-main">Edwards Aquifer</span> Source of drinking water in Texas

The Edwards Aquifer is one of the most prolific artesian aquifers in the world. Located on the eastern edge of the Edwards Plateau in the U.S. state of Texas, it is the source of drinking water for two million people, and is the primary water supply for agriculture and industry in the aquifer's region. Additionally, the Edwards Aquifer feeds the Comal and San Marcos Springs, provides springflow for recreational and downstream uses in the Nueces, San Antonio, Guadalupe, and San Marcos river basins, and is home to several unique and endangered species.

<span class="mw-page-title-main">Hine's emerald</span> Species of dragonfly

The Hine's emerald is an endangered dragonfly species found in the United States and Canada. Populations exist in Illinois, Michigan, Missouri, Ontario, and Wisconsin. Larvae are found in shallow, flowing water in fens and marshes, and often use crayfish burrows. Major threats to the species include habitat loss and alteration, and the species is legally protected in both the United States and Canada.

<span class="mw-page-title-main">Ozark cavefish</span> Species of fish

The Ozark cavefish, Amblyopsis rosae, is a small subterranean freshwater fish endemic to the United States. It has been listed as a threatened species in the US since 1984; the IUCN currently lists the species as Near Threatened, though it was previously listed as Vulnerable between 1986 and 1996. It is listed as Endangered and Threatened by the Missouri Department of Conservation.

<span class="mw-page-title-main">Devils Hole pupfish</span> Rare species of fish native to Nevada, U.S.

The Devils Hole pupfish is a critically endangered species of the family Cyprinodontidae (pupfishes) found only in Devils Hole, a water-filled cavern in the US state of Nevada. It was first described as a species in 1930 and is most closely related to C. nevadensis and the Death Valley pupfish. The age of the species is unknown, with differing analyses offering ranges between one thousand and sixty thousand years. It is a small fish, with maximum lengths of up to 30 mm (1.2 in). Individuals vary in coloration based on age and sex: males are bright metallic blue while females and juveniles are more yellow. A defining trait of this species is its lack of pelvic fins. The pupfish consumes nearly every available food resource at Devils Hole, including beetles, snails, algae, and freshwater crustaceans, with diet varying throughout the year. It is preyed on by the predaceous diving beetle species Neoclypeodytes cinctellus, which was first observed in Devils Hole in 1999 or 2000. Reproduction occurs year-round, with spikes in the spring and fall. Females produce few eggs and the survivorship from egg to adult is low. Individuals live 10–14 months.

Key Cave National Wildlife Refuge is a 1,060 acre (4.3 km2) National Wildlife Refuge located in northwestern Alabama, along the Tennessee River downstream from Florence, Alabama. Additional purchases are under negotiation which will increase the size of the refuge to 1,800 acres (7.3 km2).

The spring cavefish is the only member of the genus Forbesichthys and is one of seven species in the family Amblyopsidae. This species is listed as state endangered in Missouri, but it is considered to be of least concern by the IUCN Red List due to its relatively large population size and number of subpopulations. The spring cavefish inhabits caves, springs, spring runs, and spring seeps. It is subterranean, emerging at dusk and retreating underground an hour or two before dawn. The species is located within areas of the central and southeastern United States. It stays underground after dawn, but then emerges into surface waters at dusk. They are a carnivorous fish and are well adapted to their environment. The species' breeding behavior is rarely documented. Spawning occurs underground and in darkness between January and April. The status and distribution of cave-obligate species is incomplete or lacking entirely, which makes conservation and management decisions difficult. Kentucky and Missouri are the two main states that have their agencies managing this species in some way.

<span class="mw-page-title-main">Georgetown salamander</span> Species of amphibian

The Georgetown salamander, also known as the San Gabriel Springs salamander, is a species of salamander in the family Plethodontidae. It is endemic to springs in Williamson County, Texas, near Lake Georgetown. It inhabits freshwater springs and, possibly, caves. It is threatened by habitat loss. Many of the springs where this species formerly lived have been destroyed by development, including creation of Lake Georgetown. The specific name refers to the few remaining remnants of habitat for this species.

<span class="mw-page-title-main">Blind cave eel</span> Species of fish

The blind cave eel is a species of cavefish in the family Synbranchidae. It is the longest cavefish in Australia and one of the only three vertebrates in Australia that is restricted to underground waters, the other being the blind gudgeon and the Barrow cave gudgeon. It is blind, its body is eel-like and elongated, and it has a non-pigmented skin with colours ranging from white to pink.

<i>Typhlichthys subterraneus</i> Species of fish

Typhlichthys subterraneus, the southern cavefish, is a species of cavefish in the family Amblyopsidae endemic to karst regions of the eastern United States.

The mimic cavesnail, scientific name Phreatodrobia imitata, is a species of very small or minute freshwater snail with a gill and an operculum, an aquatic gastropod mollusk in the family Hydrobiidae.

<i>Antrolana</i> Genus of crustaceans

The Madison Cave isopod, Antrolana lira, is a freshwater, cave-dwelling crustacean species. It is in the family Cirolanidae and it is the only species of its genus Antrolana. This isopod can be found in flooded limestone caves and karst aquifers throughout the Great Appalachian Valley of Virginia and West Virginia. The Madison Cave isopod has been listed as a vulnerable species on the IUCN Red List since 1983 and as a threatened species under the United States Endangered Species Act since 1982. The species was named after the cave in which it was first discovered, Madison Saltpetre Cave. Very little is known about the life history and behavior of the Madison Cave isopod.

<i>Cambarus aculabrum</i> Species of crayfish

Cambarus aculabrum is a rare species of cave-dwelling crayfish known by the common name Benton county cave crayfish. It is native to Arkansas in the United States, where it is known from only four locations. It is a federally listed endangered species of the United States.

<i>Cambarus zophonastes</i> Species of crayfish

Cambarus zophonastes, also known as the Hell Creek Cave crayfish, is named for its original location of discovery, Hell Creek Cave. It is also found in other similar habitats in Stone County and Marion County, Arkansas. These habitats include springs and caves such as Nesbitt Spring Cave in Stone County. C. zophanastes is critically endangered according to the IUCN. C. zophanastes is also protected by the ESA as an endangered species. Currently conservation efforts focus on monitoring populations, reducing disturbances, and monitoring water quality. More research has to be conducted to better understand and conserve the species.

<span class="mw-page-title-main">Cavefish</span> Fish adapted to life in caves

Cavefish or cave fish is a generic term for fresh and brackish water fish adapted to life in caves and other underground habitats. Related terms are subterranean fish, troglomorphic fish, troglobitic fish, stygobitic fish, phreatic fish, and hypogean fish.

<span class="mw-page-title-main">Spring pygmy sunfish</span> Species of fish

The spring pygmy sunfish, Elassoma alabamae, is a species of pygmy sunfish endemic to springs in northern Alabama. It was historically known to occur in springs in North Alabama along the Tennessee River in Limestone and Lauderdale counties. The spring pygmy sunfish was first discovered in Cave Spring in Lauderdale County, Alabama in 1937 but in 1938, this site was flooded by the creation of the Pickwick Reservoir. The spring pygmy sunfish was considered extinct until its rediscovery in the Beaverdam Spring complex in 1973 by researchers from the University of Tennessee.

<i>Rhadine infernalis</i> Species of beetle

Rhadine infernalis is a species of troglobitic beetle of the family Carabidae. They are endemic to the county of Bexar, Texas. Within this county, R. infernalis has been found in 39 caves. There are 2 named subspecies of R. infernalis: R. infernalis infernalis and R. infernalis ewersi. There is a third possible subspecies that has not been officially described. R. infernalis was classified in 2000 as endangered under the IUCN Endangered Species Act of 1973, along with 8 other karst invertebrates in the same region. It has the widest known range of the endangered karst invertebrates.

References

  1. 1 2 3 4 5 6 7 8 9 10 NatureServe (2013). "Speoplatyrhinus poulsoni". IUCN Red List of Threatened Species . 2013: e.T20467A19033986. doi: 10.2305/IUCN.UK.2013-1.RLTS.T20467A19033986.en . Retrieved 19 November 2021.
  2. "Alabama cavefish (Speoplatyrhinus poulsoni)". Environmental Conservation Online System. U.S. Fish & Wildlife Service. Retrieved 13 April 2023.
  3. 1 2 42 FR 45526
  4. 1 2 53 FR 37968
  5. "Speoplatyrhinus poulsoni". Integrated Taxonomic Information System . Retrieved 18 April 2006.
  6. 1 2 3 4 5 Froese, Rainer; Pauly, Daniel (eds.) (2006). "Speoplatyrhinus poulsoni" in FishBase . March 2006 version.
  7. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Romero, Aldemaro (1998). "Threatened fishes of the world: Speoplatyrhinus poulsoni". Environmental Biology of Fishes. 53 (3): 293–294. doi:10.1023/A:1007405815580. S2CID   2960877.
  8. 1 2 3 4 Cooper, J.E., and R.A. Kuehne (1974). "Speoplatyrhinus poulsoni, a New Genus and Species of Subterranean Fish from Alabama." Copeia 1974: 486-93. doi: 10.2307/1442539
  9. 1 2 3 4 5 6 7 8 9 "Alabama Cavefish". U.S. Fish and Wildlife Service. Archived from the original on 7 October 2014. Retrieved 12 October 2011.
  10. 1 2 3 4 5 6 7 8 9 10 11 12 13 Kuhajda, Bernard, R. (2004). "The Impact of the Proposed Eddie Frost Commerce Park on Speoplatyrhinus poulsoni, the Alabama Cavefish, a Federally Endangered Species Restricted to Key Cave, Lauderdale County, Alabama". Endangered Species UPDATE. 24 (2): 57–65.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  11. 1 2 3 4 5 6 "Recovery Plan for the Alabama Cavefish" (PDF). U.S. Fish & Wildlife Service Environmental Conservation Online System. 2019.
  12. 1 2 3 4 5 6 7 8 9 10 "Alabama Cavefish Recovery Plan" (PDF). U.S Fish & Wildlife Service Environmental Conservation Online System. 1990.
  13. 1 2 3 Hawes, R. S. (1939). "The Flood Factor in the Ecology of Caves". Journal of Animal Ecology. 8 (1): 1–5. doi:10.2307/1248. JSTOR   1248.
  14. 1 2 3 "Key Cave National Wildlife Refuge, an Alabama National Wildlife Refuge located near Florence, Killen and Muscle Shoals". www.stateparks.com. Retrieved 2020-04-14.