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These fish have few or no predators because they live in caves with an impoverished fauna. They are top predators in this enclosed ecosystem.
Speoplatyrhinus poulsoni is a troglobitic fish of the family Amblyopsidae. They have no eyes and almost no pigment, making them nearly transparent. On average members of this species have a length close to 50 mm, ranging from 30-58 mm. They have an elongated, flattened head with a laterally constricted snout and a terminal mouth. Speoplatyrhinus poulsoni has no pelvic fins, a relatively high dorsal fin that mirrors the anal fin in size and shape, and a rounded paddle-shaped homocercal tail. Embedded cycloid scales cover the body and bifurcate fin rays are absent in all fins. Alabama cavefish have an elaborate system of sensory papillae on the sides and head and a hypertrophied lateral-line. The major distinguishing feature between it, and the only other cavefish in Alabama, Typhlichthys subterraneus, are the three nonpapilliferous fin rays between the medial-most rows of caudal sensory papillae (whereas T. subterraneus has 5).
Range length: 31 to 58 mm.
Average length: 50 mm.
Other Physical Features: ectothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike
The lifespan of Speoplatyrhinus poulsoni is estimated at 5 to 10 years if they survive to adult size.
Typical lifespan
Status: wild: 5 to 10 years.
Key cave, the single locale of S. poulsoni, is a large underground multi-level structure that has thousands of meters of mapped area. The pools of water in the cave in which the fish dwell are typically 5 to 10 feet deep. Seasonal flooding within the cave fluctuates this depth. Far within the cave are very deep pools of unknown depth. However no evidence exists that S. poulsoni can be found in these deep pools. Above the pools are bat roosts which, via guano droppings, supply the pools with nutrients and have established small, flourishing ecosystems. The water in the pools is groundwater with a constant temperature of about 16 C and dissolved oxygen concentrations between 7 and 9.8 ppm. The pools receive no natural light.
Range depth: 3.5 to 0 m.
Habitat Regions: temperate ; freshwater
Other Habitat Features: caves
Speoplatyrhinus poulsoni is a cavefish whose range is limited solely to Key Cave, Lauderdale County, Alabama, north of the Tennessee River.
Biogeographic Regions: nearctic (Native )
No invasive studies have been done due to the species extremely endangered status and the fragility of their cave habitat. It is thought that the diet consists of copepods, isopods, amphipods, and small cavefish. In any case S. poulsoni sits at the top of a food chain that begins with incident grey bat (Myotis grisescens) droppings, or guano.
Animal Foods: fish; aquatic crustaceans
Primary Diet: carnivore (Piscivore , Eats non-insect arthropods)
Speoplatyrhinus poulsoni is blind and therefore must rely on other senses to navigate its environment. The lateral line-system is hypertrophied, sensory papillae on the caudal fin are greatly developed, and visible ridges of neuromasts (tactile sensory organs) are present on the head and body. These are all adaptations to using primarily tactile cues in a pitch-black environment. Tactile and electroperceptile senses have replaced the sense of sight.
Perception Channels: tactile ; chemical ; electric
Speoplatyrhinus poulsoni is the rarest of all American cavefish and is likely one of the rarest of all freshwater fish. There are only an estimated 100 of these fish that live in Key Cave and their population is threatened by groundwater pollution due to the agriculture industry above the cave. Also, local bat populations around the cave have recently been threatened which puts strain on the lowest link in the food chain for S. poulsoni. Low population size and low reproductive potential make S. poulsoni extremely vulnerable.
US Federal List: endangered
IUCN Red List of Threatened Species: critically endangered
There are no negative effects of Alabama cavefish on humans.
Alabama cavefish are a fascinating example of isolated cave evolution.
Speoplatyrhinus poulsoni is the top predator in the aquatic environment of Key Cave.
Nothing is known about mating systems in this species of cavefish.
Little is known about the mate selection, life cycle, or breeding cycle of S. poulsoni. However, repeated visits to the cave have to established a summer spawning. This is interesting because it is differs from the typical pattern of late winter and spring spawnings for other species of Amblyopsidae. Some studies have suggested that S. poulsoni practices branchial incubation, based on the location of the vent and the size of the branchial chamber. The females in the population do not all reproduce annually and each fertile female only releases a few eggs per mating season. Seasonal cave flooding is responsible for hormonal changes that initiate the reproductive cycle.
Breeding interval: Alabama cavefish females breed once every several years.
Breeding season: Alabama cavefish spawn during the summer.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous
Though not yet witnessed in this species of Amblyopsidae, S. poulsoni are likely gill cavity brooders, like their kin. The male of the species is the most likely candidate to harbor the eggs untill their hatching, as is the case with the other North American cavefish.
Parental Investment: pre-fertilization (Provisioning); pre-hatching/birth (Protecting: Male)
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]
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]
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]
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]
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]
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]
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]
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]
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]
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]
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]
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. It was discovered underneath a colony of gray bats in 1967 by researchers Robert A. Kuehne and John E. Cooper and scientifically described in 1974.
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. 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. The Alabama cavefish exists in a fragile ecosystem based on nutrient-rich guano of the gray bat.
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. Thus, variations in the frequency of the cave flooding negatively affect the survival of the species.
Unfortunately, the Alabama cavefish is in danger of extinction, according to both the ESA and IUCN listings. 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.
Speoplatyrhinus poulsoni Speoplatyrhinus generoko animalia da. Arrainen barruko Actinopterygii klasean sailkatzen da, Amblyopsidae familian.
Speoplatyrhinus poulsoni Speoplatyrhinus generoko animalia da. Arrainen barruko Actinopterygii klasean sailkatzen da, Amblyopsidae familian.
Speoplatyrhinus poulsoni est un poisson aveugle, car sans yeux, de la famille des Amblyopsidae. C'est la seule espèce vivante du genre Speoplatyrhinus. Il vit uniquement dans quelques grottes des États-Unis en Alabama. Son nom américain en:Alabama cavefish est traduisible par Poisson cavernicole d'Alabama.
Speoplatyrhinus poulsoni est un poisson aveugle, car sans yeux, de la famille des Amblyopsidae. C'est la seule espèce vivante du genre Speoplatyrhinus. Il vit uniquement dans quelques grottes des États-Unis en Alabama. Son nom américain en:Alabama cavefish est traduisible par Poisson cavernicole d'Alabama.
Speoplatyrhinus poulsoni is een straalvinnige vissensoort uit de familie van de blinde baarszalmen (Amblyopsidae).[1] De wetenschappelijke naam van de soort is voor het eerst geldig gepubliceerd in 1974 door Cooper & Kuehne.
Bronnen, noten en/of referenties
Cá hang động Alabama,[2] tên khoa học Speoplatyrhinus poulsoni, là một loài cá hang động cực kỳ nguy cấp mà cuộc sống trong bể ngầm trong hang Key, nằm ở phía tây bắc Alabama, Hoa Kỳ. Đây là vị trí được biết đến duy nhất, và được phát hiện bên dưới một bầy dơi xám vào năm 1974 bởi Cooper và Kuehne.[3]
Chỉ có chín mẫu vật đã được quan sát và các nhà khoa học ước tính rằng ít hơn 100 cá thể còn sót lại trên hành tinh. Người ta tin rằng loài cá này là loài cá hang động Mỹ hiếm nhất và một trong những loài cá nước ngọt hiếm nhất. Đây là cá hang động chuyên biệt nhất được biết đến, và tồn tại trong một hệ sinh thái mong manh dựa trên chất dinh dưỡng phong phú của phân dơi xám. Các nhà nghiên cứu đã không tìm thấy nó sống trong bất kỳ vị trí nào khác.
Dữ liệu liên quan tới Cá hang động Alabama tại Wikispecies
Bài viết Lớp Cá vây tia này vẫn còn sơ khai. Bạn có thể giúp Wikipedia bằng cách mở rộng nội dung để bài được hoàn chỉnh hơn. Cá hang động Alabama, tên khoa học Speoplatyrhinus poulsoni, là một loài cá hang động cực kỳ nguy cấp mà cuộc sống trong bể ngầm trong hang Key, nằm ở phía tây bắc Alabama, Hoa Kỳ. Đây là vị trí được biết đến duy nhất, và được phát hiện bên dưới một bầy dơi xám vào năm 1974 bởi Cooper và Kuehne.
Chỉ có chín mẫu vật đã được quan sát và các nhà khoa học ước tính rằng ít hơn 100 cá thể còn sót lại trên hành tinh. Người ta tin rằng loài cá này là loài cá hang động Mỹ hiếm nhất và một trong những loài cá nước ngọt hiếm nhất. Đây là cá hang động chuyên biệt nhất được biết đến, và tồn tại trong một hệ sinh thái mong manh dựa trên chất dinh dưỡng phong phú của phân dơi xám. Các nhà nghiên cứu đã không tìm thấy nó sống trong bất kỳ vị trí nào khác.
