Threatened fishes of the world : Cyprinodon laciniatus Hubbs & Miller, 1942 (Cyprinodontidae)

Common name: Bahama pupfish. Conservation status: None. Identification: Although closely resembling the sheepshead minnow, Cyprinodon variegatus, from which C. laciniatus is believed to have been derived, the Bahama pupfish has a number of distinguishing features. While possessing the stocky profile of other members of the genus Cyprinodon, C. laciniatus is somewhat more elongate than C. variegatus. The cheek is longer, the mouth wider with more robust jaws. The teeth are markedly longer than in C. variegatus as well. The most distinguishing characteristic is the strongly and uniformly laciniate scales. Pelvic fins may be reduced or absent. D 9-12, A 9-11, P 12-16, C 14-16, LL 27-30. As in C. variegatus, sexual dimorphism in coloration is apparent. Females have more pronounced vertical dark bars and a prominent dark spot on the posterior of the dorsal fin. Males are more uniformly dusky with a pronounced dark band at the margin of the caudal fin and iridescent blue on the nape. Drawing by Renaldo Kuhler. Distribution: The type locality is Lake Cunningham, New Providence Island, Bahamas (Hubbs & Miller 1942). The author has collected this species there as well as the adjacent Lake Killarney. Abundance: The species is one of the most common fish encountered in the shallow waters of the above mentioned localities. It may be common in other bodies of water on New Providence as well. Habitat and ecology: The bodies of water that this species inhabits are brackish with salinities ranging from 10–14 ppt. The bottom is marl over limestone in the form of coarse cobble and boulders. Algae, chiefly Batophora are abundant. Transect studies reveal the greatest abundance of individuals to be within 10 m of the shore at depths ranging from 0.3 to 1.2 m. Although feeding studies have not been done, the Bahama pupfish is probably similar to the sheepshead minnow in consuming mainly plant matter and detritus. The differences in dentition between the two species suggest some feeding specializations, however. Reproduction: Although studies on the reproductive biology of C. laciniatus have not been done, fecundity measurements of several populations of Cyprinodon from New Providence have been performed. Total number of eggs produced closely correlates with size of the individual and ranges from 20 to 250 eggs per ovary. The presence of eggs at different stages of maturation indicates that spawning takes place throughout the year. Threats: The restricted distribution of this species alone should merit its being considered threatened. While the Bahamas possesses a rich and diverse ichthyofauna, less than one percent can be considered endemic (Smith-Vaniz & Bohlke 1991). In the course of surveying fish populations in the inland waters of the Bahamas, a number of exotic cyprinodontiform species have been discovered. Smith-Vaniz & Bohlke (1991) reported that the sailfin molly, Poecilia latipinna, has been present in Lake Cunningham since 1972. Barton & Wilmhoff (1996) reported P. latipinna elsewhere on the island of New Providence and also recorded the presence of two species of the genus Xiphophorus. Of most concern, however, is the widespread introduction of cichlids. Two species, Oreochromis mossambicus and Herotilapia multispinosa have been observed. Of the two species, Oreochromis is especially widespread having been collected at a number of localities including lakes Cunningham and Killarney. Tilapia apparently were first introduced to the Bahamas sometime during the 1960’s as part of an abortive aquaculture project. The Bahamas Department of Environmental Health has distributed Gambusia in ponds throughout the island for mosquito abatement. Their inadvertent introductions of Oreochromis, together with deliberate relocation for purposes of developing harvestable stocks in selected ponds, are the probable reasons for the rapid spread of Oreochromis throughout the island. Inadvertent introductions of cichlids have had a deleterious effect on native fishes, especially cyprinodonts. Schoenherr (1985) reported on the elimination of desert pupfish, Cyprinodon macularius, in an irrigation drain where Tilapia zilli was introduced. Courtenay et al. (1985) reported that the suppression of populations of springfish, Crenichthys baileyi, was suspected to be attributed to introduced convict cichlids, Cichlasoma nigrofasciatum. Tippie et al. (1991) verified this by demonstrating the adverse impact of convict cichlids on growth and recruitment of springfish under experimental conditions. Stevenson (1992) reported on the explosive growth in Tilapia populations in Lake Chichancanab, the site of a remarkable species flock of Cyprinodon. The species flock is apparently suffering from the introduction of Tilapia melanopleura which took place over ten years ago (S. Contreras Balderas personal communication). Conservation action: The conservation officer of the Bahamas Department of Agriculture has been alerted to the problem of exotic species and their impact on endemic forms. The author is currently engaged in a life history study of the Bahama pupfish. To date, no specific action has been taken to guarantee the future survival of the species. Conservation recommendation: It is unrealistic to attempt eradication of cichlids and other exotic species, especially in larger bodies of water. Smaller, more isolated ponds can be established, however, and stocked only with native species. Remarks: Miller (1962) claimed that only two species of the genus Cyprinodon, one of these being C. laciniatus, can be readily distinguished within the species complex presumably derived from C. variegatus that exists throughout the West Indies. The author is currently collaborating on studies of the evolution of West Indian cyprinodonts. A species complex endemic to San Salvador Island has been tentatively identified (Grant Gilmore personal communication). It is likely that systematic studies will reveal the existence of additional species in the Bahamian archipelago that, because of their endemic nature, will merit conservation as well.