(This article was originally published in Cichlid News Magazine in four parts; Jul-95 pp. 18-23 (part 1), Oct-95 pp. 22-25 (part 2), Jan-96 pp. 21-25 (part 3), Apr-96 pp. 8-12 (part 4), It is reproduced here with the permission of author Paul V. Loiselle).
In his best-selling novel Jurassic Park, author Michael Crichton stocked an imaginary island off the coast of Costa Rica with an assortment of dinosaurs brought back from extinction through the wonders of genetic engineering. Crichton's scientists had to go to great lengths to retrieve fragments of dinosaur DNA from blood-sucking insects preserved in amber in order to clone the dinosaurs. Had the eccentric entrepreneur who conceived the project been disposed to stock the waters of his theme park with appropriately ancient cichlids, however, this goal could have been accomplished far more quickly and economically. To collect the cichlids of Jurassic Park would require nothing more than a trip to the island of Madagascar.
To visit Madagascar is to visit a world out of time. Totally isolated in the Indian Ocean for at least 65 million years, this mini-continent is home to plants and animals found nowhere else in the world. Since the island was first visited by European naturalists in the 17th century, scientists have been well aware of the unique character of the Malagasy biota, an awareness that a growing number of non-professionals has come to share in recent years (Jolly et al., 1984). However, this awareness usually stops short of Madagascar's freshwater fishes. Its considerable biological interest notwithstanding, the Malagasy ichthyofauna is familiar neither to the general public nor to the scientific community at large. As cichlids figure prominently in this ichthyofauna, which includes many attractive species well-suited for aquarium life, it is even more surprising that aquarists are equally ignorant of these fishes. My goals in this article are to introduce the readers to the cichlids of Madagascar, summarize what is known of their status in nature, and suggest ways by which concerned hobbyists can assist in their conservation.
Excluding species that return to the sea to breed or that enter freshwater only episodically, Madagascar supports 62 native fishes referable to 12 families (Loiselle and Stiassny, 1993; Nourissat, 1992; Reinthal and Stiassny, 1991; Stiassny, 1990). Twenty distinct cichlid taxa occur on the island, eleven formally recognized and nine whose status remains to be clarified or which are awaiting description (Table 1). Given that Madagascar is the fourth largest island in the world with a surface area of 229,849 square miles (about the same as that of Texas) this represents a remarkably small complement of freshwater fishes. By way of comparison, New Guinea, an island of comparable size and climate, supports 197 species of freshwater fishes (Allen, 1991). Ichthyologists familiar with the island consider it highly probable that further research will turn up additional Malagasy freshwater fishes. Indeed, that collecting efforts undertaken over the last five years led to the rehabilitation of one species of cichlid from synonymy and to the discovery of one new freshwater herring, one new cyprinodont, nine new bedotiids and six new cichlids clearly demonstrates that Madagascar's fish fauna is far from completely known. Nevertheless, for Madagascar's ichthyofauna to match that of New Guinea's, it would have to nearly double in size, a highly unlikely contingency.
|T||Paratilapia bleekeri Sauvage 1882|
|T||Paratilapia polleni Bleeker 1868|
|X||Paratilapia sp. nov. Lac lhotry|
|?||Ptychochromis oligoacanthus Bleeker 1868|
|?||Ptychochromis nossibeensis Bleeker 1868|
|?||Ptychochromis cf. nossibeensis/Lac Deux Soeurs|
|?||Ptychochromis cf. nossibeensis/Lac bempazava|
|?||Ptychochromis sp. Saroy|
|X||Ptychochromis sp. Kotro|
|E||Ptychochromoides betsileanus (Boulenger 1899)|
|E||Ptychochromoides sp. Fia Potsy|
|E||Ptychochromoides sp. Nosivolo|
|?||Paretroplus dami Bleeker 1878|
|?||Paretroplus polyactis Bleeker 1878|
|E||Paretroplus petiti Pellegrin 1929|
|T||Paretroplus keineri Arnoult 1960|
|E||Paretroplus maculatus Keiner & Mauge 1966|
|E||Paretroplus sp. Lac Sarodrano|
|E||Paretroplus sp. lamena|
|?||Oxylapia polli Keiner & Mauge 1966|
Of the island's non-anadromous freshwater fishes, all save two gobies are endemic at the species level (Reinthal and Stiasny, 1991). In this respect, the ichthyofauna of Madagascar compares favorably with its better known terrestrial biota. The Madagascar rainbowfishes of the family Bedotiidae occur nowhere else in the world. Recent studies (Mo, 1991) suggest that the catfishes of the family Ariidae actually represent an undescribed family, likewise endemic to Madagascar. All five genera of native cichlids are endemic to the island, as is the silversides genus Teramulus and two genera of sleeper gobies, while the killifish genus Pachypanchax occurs only on Madagascar and the adjacent Seychelles Islands.
The relationships of Madagascar's freshwater fishes reveal much about their evolutionary history. Malagasy cichlids were formerly thought to represent two quite distinct lineages (Regan, 1920; Kiener and Mauge, 1966). The one, comprising the genera Paratilapia, Ptychochromis, Ptychochromoides, and Oxylapia, was thought to be most closely related to African cichlids. The other, comprising the genus Paretroplus, had as its closest relatives the chromides of the genus Etroplus, native to Sri Lanka and southern India. However, recent and more detailed studies of their anatomy (Stiassny, 1991) have turned up evidence that the Malagasy cichlids are more closely related to one another than to any of the family's numerous African representatives and that together with the genus Etroplus, appear to represent a natural evolutionary grouping. There is also evidence suggesting affinities between Pachypanchax and the south Asian killifish genus Aplocheilus (Scheel, 1968; Parenti, 1981), while Madagascar's silversides and rainbowfishes seem to have their nearest living relatives in Australasia (Stiassny, 1990).
These results are less surprising than they might at first glance seem. Australasia, the Indian subcontinent, Madagascar, and the Mascarene Islands are all fragments of the ancient southern supercontinent of Gondwanaland. Given the inability of freshwater fishes to cross saltwater barriers, the presence of clearly related taxa on these now widely separated land masses argues persuasively that their common ancestors must have been present in the waters of Gondwanaland prior to its fragmentation. As proto-India and Madagascar split off from Gondwanaland ca. 165 million years ago (Rabinowitz et al., 1983), the distributional pattern of the etropline cichlid lineage testifies eloquently to both its extreme antiquity and that of the family Cichlidae.
Together with extreme antiquity and a high degree of endemism, Madagascar's native freshwater fishes share yet another distinction with most of the island's terrestrial animals a high level of endangerment. Because Malagasy cichlids are highly appreciated food fish, their decline over time has been recorded with some degree of precision by fisheries biologists working on the island. Unambiguous references to observed range contractions of formerly widespread species of commercial importance date back to the 1950's (Kiener, 1959, 1963). However, the work of Drs. Peter Reinthal and Melanie Stiassny appears to be the first attempt to make a comprehensive assessment of the conservation status of Madagascar's non-anadromous freshwater fishes.
Their paper was based upon an exhaustive analysis of the published literature, a thorough examination of museum collections, and their own field work in Madagascar. Published in 1991, it documented unambiguously the perilous condition of many Malagasy fishes. Subsequent accounts by European aquarists who visited Madagascar in search of native cichlids (de Rham, in press; Nourissat, 1992, 1993a, b) offer further evidence of the decline of the island's native cichlids. The results of my collecting trips made with Roy Morris in 1993 and Oliver Lucanus in 1994, while providing further insights into the problems facing its native fishes, present the same overall picture of an ichthyofauna in crisis. The following synopsis of the status of the Malagasy cichlid fauna is drawn from all three sources of data.
Members of the genus Etroplus from southern India and Sri Lanka are believed to be the closest living relatives of the cichlids of Madagascar; a male Etroplus suratensis is shown. Photo by Paul V. Loiselle.
Review of the Cichlids of Madagascar
The Genus Paratilapia Bleeker 1868
Paratilapia polleni was described by the Dutch ichthyologist Bleeker in 1868 on the basis of material collected from northwestern Madagascar. The nineteenth century saw several additional Paratilapia species subsequently described from Madagascar as well as the attribution of numerous African species to the genus (Boulenger, 1915). In 1904, the French ichthyologist Jacques Pellegrin synonymized the Malagasy Paratilapia species. In his subsequent revision of the genus, C. Tate Regan (1920) took Pellegrin's reasoning even further, accepting as valid only a single Malagasy species, P. polleni, and referring the numerous nominal African Paratilapia to other genera. Several field biologists noted the existence of distinct local phenotypes of marakely, to give this species its most widely used vernacular name (Catala, 1977; Kiener, 1963; Kiener and Mauge, 1966). However, Regan's view of the monotypic nature of the genus went unchallenged until aquarists had the opportunity to work with two of these putative color forms. Differences in both color pattern and behavior strongly suggested that these populations represented more than merely local races of a single species.
|An adult male "small spot" marakely, Paratilapia polleni. Photo by Paul V. Loiselle.|
Subsequent investigations turned up diagnostic morphological differences between the so-called "large-spot" and "small-spot" marakely, which proved referable to the species Paratilapia bleekeri Sauvage 1882 and P. polleni, respectively (Loiselle and Stiassny, 1993). The re-examination of museum specimens of nominal P. polleni undertaken during the course of this study resulted in the discovery of a third, undescribed Paratilapia from Ihotry, a large lake in the Onilahy River basin of southwestern Madagascar. References to a distinctive race of Paratilapia inhabiting highly mineralized hot springs near the city of Fort Dauphin in southeastern Madagascar (Kiener, 1963) suggest the genus probably comprises additional undescribed species. The status of distinctive phenotypes of Paratilapia polleni collected from Vatomandry in the eastern coastal region of Madagascar in 1993 by Nourissat and de Rham and of P. bleekeri native to the middle reaches of the Namorona River brought back by Loiselle and Lucanus in 1994 also remains to be determined.
Earlier workers (Catala, 1977; Kiener, 1963; Kiener and Mauge, 1966) attributed both an extensive range and great physiological tolerance to P. polleni, one of the few Malagasy cichlids known to survive the low winter temperatures of the island's central highlands. These assertions need to be reexamined in light of present knowledge of Paratilapia systematics. De Rham (in press) confirms the continued presence of P. polleni on the offshore island of Nosy Be and reports the occurrence of this species from highland streams tributary to the Mangoky River near the town of Ambalavao in southwestern Madagascar. The present North American aquarium strain of P. polleni is descended from fish collected from a small lake near the mouth of the Mangoro River by Reinthal and Stiassny (Stiassny and Gerstner, 1992). Specimens they collected from several other localities along the eastern coastal plain (Reinthal and Stiassny, 1991) are also referable to this species.
The type locality of P. bleekeri is given as marshes in the vicinity of Antananarivo, Madagascar's capital city. De Rham (in press) documents its presence in the basins of the westward draining Sofia, Anivorano-Nord, and Betsiboka Rivers as well as from several localities along the east coast of the island. If the strikingly marked marakely under pond culture at the Service des Peches facility at Ifanadiana that I encountered in 1994 proves referable to P. bleekeri, the distribution of this species on the eastern versant of Madagascar extends at least as far south as the Namorona River.
An adult female "large spot" marakely, Paratilapia bleekeri. Photo by Paul V. Loiselle.
The present ranges of both species thus seem to overlap along Madagascar's eastern versant. Whether the sole occurrence of P. bleekeri in the rivers of the Menabe region and of P. polleni in the Mangoky represent the true distribution of these two species or an artifact of limited collecting effort remains to be determined. However, the presence of P. polleni in the Ambalavoa region does suggest that both species of Paratilapia can tolerate low winter water temperatures well enough to colonize highlands habitats, although there is no way to presently ascertain whether they co-occurred in this region historically.
While both species of Paratilapia are still widely distributed in the coastal lowlands of Madagascar, they are nowhere abundant (Bardin, 1983; de Rham, in press; Nourissat, 1992). Although a relic population of P. bleekeri was present in the Manganosy Swamp just outside Antananarivo as late as 1978 (Raminosoa, 1979), intensive collecting efforts mounted ten years late failed to turn up any native cichlids on the central plateau (Reinthal and Stiassny, 1991). De Rham (in press) collected a single specimen of P. polleni from Lac des Deux Soeurs on Nosy Be in 1992. My attempt to secure additional material of this species from Nosy Be in 1994 proved unsuccessful. When shown color photographs of this species, local fishermen indicated that while still present on the island, fony (as this species is known locally) had become extremely rare. Some idea of the extent to which Paratilapia populations have declined may be had from statements made to me last year by the Assistant Director of the Forestry Research Station of Ampijoroa, situated in the lower Betsiboka drainage. When he was first posted to Ampijoroa in 1976, this enthusiastic angler found it a simple matter to catch a string of ten to twelve large marakely in an afternoon's casual fishing. By way of contrast, the combined efforts of several dozen professional fishermen living in villages adjacent to the forest reserve yielded only three marakely in 1992.
The depredations of an exotic predator, the black bass, Micropterus salmoides, appear largely responsible for the extirpation of the marakely in the central highlands of Madagascar. while the Asian snakehead, Channa striata, is likely to have the same effect on populations in the coastal lowlands (Raminosoa, 1987). Certainly the Malagasy fishermen with whom Roy Morris and I spoke dated the decline of P. bleekeri in the Betsiboka basin from the first appearance of the snakehead therein in 1976. However, these predators cannot account for the rarity of P. polleni on Nosy Be, as neither has been to date introduced to this offshore island. De Rham (in press) appears to have correctly identified heavy fishing pressure on this much appreciated food fish (Kiener, 1963) as another significant factor in the progressive disappearance of Paratilapia species from much of their former range.
In Lac Tsimbazaza near Tana, native Paratilapia bleekeri have been replaced by introduced tilapia and carp. Photo by Paul V. Loiselle.
For the present, both P. polleni and P. bleekeri appear to be maintaining viable populations along the east coast of Madagascar. This appears due to their ability to live and breed in slightly brackish water, a physiological adaptation that affords them access to habitats barred to exotic predators. As there appears to be no realistic hope of either reducing fishing pressure on this or any other indigenous Malagasy cichlid or of preventing the further spread of the snakehead, the long-term prospects of these two species elsewhere on Madagascar are poor. Fortunately, both species of Paratilapia have been successfully bred in captivity (Nourissat, 1992; Loiselle, 1993a, b) and are being produced on a commercial scale in Florida. As both are strikingly colored, relatively unaggressive cichlids, it seems quite likely that little beyond the operation of normal market forces will be required to assure their long-term survival under management.
The conservation status of the third, undescribed Paratilapia species from Lake Ihotry is unclear. The only known preserved material of this species was collected in the 1930's. Ihotry is a lake whose surface area, volume, and salinity are entirely dependent upon annual rainfall. As southwestern Madagascar is characterized by frequent serious droughts, the lake sporadically becomes too saline to support freshwater fishes. The last such documented episode took place in 1939. Fish populations in the lake subsequently rebounded following several seasons of abundant rainfall. Presumably freshwater springs provide a refuge from which survivors can emerge to recolonize Lake Ihotry when conditions again become favorable for fishes. The present fishery is based on introduced tilapias rather than native cichlids (Stiassny, pers. comm.). Clearly timely collecting is in order to ascertain the fate of both this species and the distinctive Ptychochromis phenotype known to occur in Lake Ihotry.
The genus Ptychochromis comprises three nominal species. The type species, Ptychochromis oligoacanthus (Bleeker 1868), was described from specimens collected from the Samberano River in northwestern Madagascar and from Lake Ampombilava on the off-shore island of Nosy Be. Bleeker recognized that the Nosy Be and Samberano samples differed considerably in coloration and proposed the varietal name nossibeensis for the insular population. Two subsequently described species, Ptychochromis grandidieri Sauvage 1891 and Ptychochromis madagascariensis Sauvage 1891, based upon material reportedly collected from Lake Itasy, were considered by the latest revisers of the genus (Kiener and Mauge, 1966) to be junior synonyms of Ptychochromis oligoacanthus. Those same authors recognized four distinct "races" of Ptychochromis oligoacanthus, each with a discrete range. Nourissat (1992) and de Rham (in press) have recorded a fifth phenotype, restricted to the Lac des Deux Soeurs, a crater lake on the island of Nosy Be. My own recent collecting on that island has turned up equally distinctive and very differently colored populations from Lac Ampombilava and Lac Bempazava.
|A young male Ptychochromis nossibeensis, known locally as tsipoy, from Lac Djabala on the island of Nosy Bé. Photo by Paul V. Loiselle.|
|A second variant of Tsipoy is found in Lac des Deux Soeurs, another crater lake on Nosy Bé. Photo by Paul V. Loiselle.|
According to local informants, tsipoy, as Ptychochromis is known on Nosy Be, are to be found in each of the island's nine crater lakes. The results of collecting efforts made to date strongly suggest that each lake supports its own distinctive Ptychochromis phenotype. Specimens from the three lakes sampled to date differ so markedly in color pattern that they, like Kiener's putative races, are in all likelihood specifically distinct. Clarification of the taxonomic status of the Nosy Be Ptychochromis must await a comprehensive survey of the island's crater lakes, an exercise complicated by the fact that a number of fady (local taboos) (no less than the presence of dangerous crocodiles in all of them) serve to inhibit sampling efforts.
Given this state of affairs, the nomen Ptychochromis oligoacanthus should be restricted to Kiener's northwestern race, known locally as juba. The name nossibeensis applies to the Ptychochromis found in Lakes Ampombilava and Djabala on Nosy Be. The formal descriptions of the remaining Ptychochromis await determination of which if any of these taxa correspond to Sauvage's two nominal species. In all likelihood, one of these names should apply to Keiner's southwestern race, known to the Malagasy as kotro. Sorting this matter out is not made any easier by the fact that the stated type locality of both Ptychochromis grandidieri and Ptychochromis madagascariensis is clearly in error. No specimens of any Ptychochromis have been subsequently taken from Itasy, a well-collected highland lake (Kiener and Mauge, 1966).
Individuals of Ptychochromis oligoacanthus as narrowly defined are characterized by an indistinct pattern of lateral blotches on a silvery blue background, wine-red dorsal fin lappets, and a wine red flush over the caudal and anal fins. Juba, as it is known in Malagasy, is restricted to the westward flowing rivers in the extreme north of Madagascar from the Mahavavy du Nord southward to the Sofia. It appears probable that the intensely colored Ptychochromis reported by Keiner from Ambalafary, a small lake in the upper Sofia River basin near the town of Mandritsara, represents an extreme phenotype of juba. It is unlikely that this question will ever be answered, as the Lake Ambalafary Ptychochromis is extinct (de Rham, in press). Nourissat (1993a) reports juba to be locally abundant in the lower Sofia and Ankofia River basins. This species has been exported to France, but has not to date bred in captivity (Nourissat, pers. comm.).
Sexually active individuals of Ptychochromis nossibeensis are clear olive beige shading to sooty black ventrally. The flanks are marked with small metallic blue dots. Five large black spots are spaced equidistantly along the midlateral line. The ventral fins are deep black, the anal fin and spiny dorsal uniformly dusky. The soft dorsal and the tail of sexually active individuals are uniform light iridescent blue. In tsipoy from the Lac des Deux Soeurs, the metallic blue flanks are marked with a series of vertical black bands that extend into the dorsal fin. The throat and ventral region are dusky, the ventrals uniform jet black. The otherwise uniformly dusky vertical fins sport an attractive metallic blue wash. Sexually active Ptychochromis from Lac Bempazava are clear beige, each scale on the flanks broadly edged in metallic green. The first spot in the midlateral series is large and clearly defined. The third is also well defined and extends upwards into the spiny dorsal fin. The second, fourth and fifth are much reduced in size. The dorsal and caudal fins are grey with a medium blue wash, the anal sooty, the ventrals deep black. Juveniles of this attractive cichlid have a metallic green wash dorsally reminiscent of the green chromide.
Juveniles of both Ptychochromis nossibeensis and of Ptychochromis cf. nossibeensis/Lac Bempazava were exported to North America in 1994. Ptychochromis cf. nossibeensis/l.ac des Deux Soeurs is presently being maintained in Switzerland, but has not to date bred in captivity (de Rham, pers. comm.). While it is to be hoped that all three of these very attractive cichlids will ultimately breed in captivity, success in this undertaking is a matter of much less urgency for these forms than for most of Madagascar's other endemic cichlids. While Tilapia rendalli is present in all the island's crater lakes, this species does not appear to dominate these bodies of water in the same manner that it does other habitats on Madagascar proper. Naturalized populations in the four lakes sampled in 1994 had an emaciated appearance and were much less abundant than the native cichlids, whose appearance suggested robust good health. None of the tsipoy populations appears to be seriously threatened, a state of affairs that should continue as long as Nosy Be remains free of black bass and snakeheads.
Ptychochromis sp. 'saroy' can be instantly recognized by the series of large black blotches both juveniles and sexually quiescent adults sport along the midlateral line and the presence of creamy-white lappets in the spiny dorsal fins of otherwise dusky sexually active adults. Saroy occurs along the entire eastern coast of Madagascar, from the Loky River in the far north southward to the city of Fort Dauphin. It is a characteristic inhabitant of the lower courses of rivers, typically penetrating as far inland as the first major rapids system (Catala, 1977). Both Reinthal and Stiassny (1991) and Nourissat (1992) report it as still locally abundant in the Pangalanes, a series of interconnected coastal lagoons that link the outlets of eastward flowing rivers from the Ivondro, which enters the Indian Ocean just south of the port city of Toamasina southward to the Manampatrana. Its ability to survive in slightly brackish water probably accounts for the persistence of substantial populations of this species in coastal lagoons and the lower courses of rivers. Saroy is a biparentally custodial substratumspawning cichlid (Catala, 1977) that has been successfully bred in both large aquaria and outdoor ponds in southern France (Nourissat, 1992; pers. comm.). As there is no reason to believe that the latter achievement cannot be duplicated in Florida, the eventual introduction of this strikingly marked cichlid to American aquarists is only a matter of time.
Sexually quiescent individuals of the last and largest of the taxa reported from the main island, Ptychochromis sp. 'kotro', are uniform grayish-brown fish with a lighter ventral region and clear beige vertical fins. Juveniles may be marked with indistinct lateral blotches, but these disappear in adults. This cichlid is restricted to the dry southwestern corner of Madagascar. Kiener and Mauge (1966) indicate its range as extending from Lake Ihotry southward to the lower reaches of the Onilahy River. De Rham and Nourissat failed to collect this distinctive, geographically isolated Ptychochromis from the lower Onilahy in 1994, and there is a real possibility that the Lake Ihotry population (vide supra) may be extinct. Ptychochromis sp.lkotro should thus be considered seriously endangered.
The Genus Ptychochromoides Kiener and Mauge 1966
The genus Ptychochromoides comprises a single described and two undescribed species. Ptychochromoides betsileanus (Boulenger 1899) was described from clear-flowing highland streams to the south of the city of Fianarantsoa. The specific epithet commemorates the Betsileo people, within whose territory the type material was collected. This commercially significant cichlid was known to the Merina people of the Lake Itasy region as trondro mainty [=black fish] and to French settlers as marakely a bosse [=humpheaded marakely!, both vernacular names referring to the most obvious superficial characteristics of breeding individuals. Large adult size and uniform deep black coloration taken in combination with a well-developed nuchal hump, flowing soft dorsal and anal fins, and a deeply emarginate tail make sexually active Ptychochromoides betsileanus among the most striking of Malagasy cichlids.
A robust species with a preference for clear, well-oxygenated waters and rocky bottoms, trondro mainty was formerly sufficiently abundant in Lake Itasy to support a major commercial fishery, which marketed its catch in Antananarivo, 100 kilometers distant (Kiener, 1959). By the late 1950's, erosional sedimentation appears to have eliminated many of the traditional breeding sites of this biparentally custodial substratum spawning cichlid. The associated eutrophication of the lake basin together with the impacts consequent upon the successive introduction into Lake Itasy of goldfish, carp, Tilapia rendalli, Oreochromis niloticus, and the black bass, combined with heavy fishing pressure to further reduce the numbers of trondro mainty (Kiener, 1963). Two decades later, this distinctive Ptychochromoides had disappeared completely from the fishery. The total failure of efforts to collect trondro mainty in 1989 and 1990 (Reinthal and Stiassny, 1991; Nourissat, 1992) taken with its absence from commercial fish catches for the past fifteen years lead inescapably to the conclusion that this distinctive cichlid is extinct in the Lake Itasy region.
In the fall of 1994 de Rham and Nourissat discovered a breeding population of trondro mainty several hundred kilometers southwest of its previously recorded range in the Ilanala, a tributary of the Onilahy River. It is unclear whether this population represents a relic of a formerly more extensive distribution or is the result of a previous translocation. A single pair of this largest of Madagascar's native cichlids was successfully exported to Old World Exotic Fish, Inc. in Florida, while Nourissat carried a number of fry back to France. Regrettably, the female of the adult pair did not long survive her arrival in the U.S. However, as of early 1995 the juveniles brought to France continue to prosper. While it is to be hoped that Ptychochromoides betsileanus will prove as amenable to breeding in captivity as the other Malagasy cichlids to date exported, securing additional founders is clearly essential to the establishment of a viable managed population of this critically endangered species.
Earlier attempts by Nourissat and his collaborators to collect breeding stock of Ptychochromoides betsileanus from its type locality have led instead to the discovery of a distinctive Ptychochromoides phenotype that appears to represent a second species. Known locally as fia potsy [=white fish], this species has a clear gray base color, a yellowish ventral region and an orange-red flush in the caudal fin. Although this is also a robust cichlid, growing to 35.0 cm SL, even large males lack the massive nuchal hump so characteristic of Ptychochromoides betsileanus (de Rham, in press). The initial effort to collect specimens of fia potsy from relatively undisturbed streams to the south of Fianarantsoa proved unsuccesful (Nourissat, 1993b). On the strength of persistent reports by local fishermen that this cichlid was still extant, albeit extremely rare, a second attempt was made to find this Ptychochromoides in 1993. Two large specimens were collected by local fishermen in the Manantanana, a headwaters tributary of the westward-flowing Mangoky River (de Rham, in press), thus confirming the continued existence of this species. Regrettably, these specimens only survived for 48 hours after their capture. Securing breeding stock of this extremely endangered species clearly remains a high priority goal. This task will be complicated by both its preferred habitat of deep stretches of river flowing over well-scoured rocky bottoms and its extreme rarity. Fia potsy used to be so abundant in the Betsileo country that fishermen could catch up to 40 kilograms with a single pass of a large seine (Kiener, 1959). This stands in stark contrast to the three specimens sold in the market of the town of Ambalavoa in the week prior to the arrival of Nourissat and de Rham in 1993!
In 1989 Reinthal and Stiassny discovered a distinctive Ptychochromoides species in the Nosivolo, a tributary of the eastward-flowing Mangoro River, not far from the town of Marolambo. De Rham and Nourissat found it a relatively simple matter to collect individuals of this species from the type locality in the fall of 1994. They encountered serious problems in keeping specimens alive and succeeded in getting only three individuals back to France. Such a small number of founders does not augur well for the outcome of breeding efforts. However, both its abundance and the ease with which it can be captured should facilitate future efforts to secure a more reasonable number of founders.
According to de Rham (in press), local fishermen described a black and yellow cichlid identical to the Nosivolo species as occurring in the middle reaches of the Namorona River, which empties into the Indian Ocean nearly 200 kilometers to the south of the Mangoro. These observations suggest that this new Ptychochromoides may be widely distributed in southeastern Madagascar. In contrast to the situation of its two congeners, the conservation status of Ptychochromoides sp./ Nosivolo seems for the moment reasonably secure. Its preference for fast-flowing water affords it a degree of protection from introduced predators, while the erosive sedimentation that afflicts most of the westward-flowing rivers of Madagascar has to date proven less of a problem in this portion of the island. This is doubtless due to the fact that watersheds in southeastern Madagascar still support stands of relatively undisturbed forest. As long as this situation persists, the Nosivolo Ptychochromoides should be able to sustain its present population levels.
The Genus Oxylapia Kiener and Mauge 1966
Oxylapia polli in the aquarium. Fish and Photo by Patrick De Rham.
Oxylapia polli Kiener and Mauge 1966 is the sole known representative of its genus. This highly modified rheophilic species was described from material collected in the rapids of the Mangoro River near the town of Marolambo. Reinthal and Stiassny found a substantial population still extant at the type locality in 1989 (Stiassny, pers. comm.). Rapids are of their nature extremely difficult to sample, while vehicular access to comparable habitats elsewhere on the eastern verdant of the island is virtually impossible. Hence the possibility that O. polli is more widely distributed cannot be dismissed out of hand, particularly in light of the apparently more extensive range of the syntopically occurring Nosivolo Ptychochromoides. Pending the results of a systematic survey of the freshwaters of Madagascar presently in progress, no more can be said of the status of this distinctive species.
Impassable roads blocked the initial attempt to collect breeding stock of O. polli in 1993 (Nourissat, pers. comm.). De Rham and Nourissat flew into Marolambo in the fall of 1994 and were successful in capturing a number of O. polli. Although these specimens appeared to adapt well to holding tanks in Antananarivo, none of them survived long enough to be shipped to France. Hopefully subsequent efforts to establish a breeding population of this distinctive cichlid in captivity will prove more successful.
The Genus Paretroplus Bleeker 186S
The genus Paretroplus comprises six described and one undescribed species. Superficially, only their more deeply emarginate caudal fins distinguish the damba, as they are collectively known to most Malagasy fishermen, from their close relatives, the chromides of the genus Etroplus. Damba are robust, deep-bodied cichlids capable of growing to 30.0 cm SL. Greatly esteemed for their delicious flesh by Malagasy and foreign consumers alike (Catala, 1977), damba formerly supported important fisheries on both coasts of Madagascar (Kiener, 1963). The coexistence of two chromide species over much of southern India and Sri Lanka is facilitated by their quite different feeding patterns. The green chromide, Etroplus suratensis (Bloch 1790), is largely herbivorous, while the smaller orange chromide, Etroplus maculatus (Bloch 1795) feeds primarily upon aquatic invertebrates. The documented coexistence of four species of Paretroplus over an extensive region of northwestern Madagascar (Kiener, 1963; Kiener and Mauge, 1966) is less easily explained, as all species of the genus possess essentially identical pharyngeal dentition and appear to share the same omnivorous feeding patterns.
All damba are biparentally custodial substratum spawners. Malagasy fishermen that Roy Morris and I interviewed in 1993 indicated that all the species found on the western versant of the island had a highly seasonal reproductive pattern, spawning from August through October, the last half of the dry season. Several fishermen stated that damba only spawn once a year. However, we were unable to ascertain the basis for this assertion. Our informants indicated that the western slope damba deposit their egg plaques on waterlogged wood. This observation accords with the account provided by Catala (1977) on spawning site preferences in the east coast species, P. polyactis. The only exception to this pattern in nature is the rheophilous lamena, which appears to be a cave-spawner (Nourissat, 1993b). Damba are probably more flexible in their choice of spawning sites than these observations would suggest, as specimens of P. kieneri, P. maculatus, P. petiti, and Paretroplus menarambo under pond culture in Florida have shown themselves to be quite partial to artificial caves (Morris, pers. comm.).
|A subadult Paretroplus polyactis from the eastern versant of Madagascar. Photo by Paul V. Loiselle.|
|An adult male Paretroplus dami in the aquarium, the bicolor damba. Photo by Paul V. Loiselle.|
Paretroplus petiti, known as kotso in Madagascar. Photo by Paul V. Loiselle.
Paretroplus kieneri from Lac Ravelobe. Photo by Paul V. Loiselle.
|The spotted damba, Paretroplus maculatus occurs with Paretroplus kieneri in Lac Ravelobe. Photo by Paul V. Loiselle.|
|The pinstripe damba, Paretroplus menarambo, a species from Lake Sarodrano. Photo by Paul V. Loiselle.|
|An undescribed species of Paretroplus, the lamena or "red fish" is the only known rheophilic member of the genus. Photo by Paul V. Loiselle.|
Paretroplus polyactis Bleeker 1869 is the only damba species known to occur on the eastern versant of Madagascar. Masoavotoaka (= eyes bloodshot from drinking rum), as this species is known to the Malagasy, ranges along the eastern coast of the island from Diego Suarez in the extreme north to Fort Dauphin in the south. Like Ptychochromis sp./saroy, P. polyactis is a characteristic inhabitant of coastal lagoons and the lower reaches of large rivers (Catala, 1977). Though masoavotoaka rarely occurs above the head of navigation, Nourissat (pers. comm.) encountered a breeding population well inland during the course of his 1993 collecting trip. This is the most salt-tolerant Paretroplus species, capable of surviving salinities as high as 15.0 parts per thousand (Kiener and Mauge, 1966). By virtue of this physiological adaptation, P. polyactis is sheltered from the impact of exotic competitors and predators in much the same manner as the saroy. In consequence, masoavotoaka is the only Paretroplus species that still supports an important fishery and whose conservation status affords some grounds for optimism. Catala (1977) reports that juveniles of this species make attractive aquarium residents but was unable to elicit spawning either in tanks or in an outdoor pond in Madagascar. More recent efforts (Nourissat, 1992) foundered on the extreme susceptibility of this species to protozoan parasites and Saprolegnia. As masoavotoaka is both colorful and relatively accessible to collectors, its future exportation is highly likely. This will hopefully be followed by a report of a successful spawning in captivity.
Paretroplus dami Bleeker 1869 was described from material collected from Lake Ampombilava on Nosy Be, an island located off the northwest coast of Madagascar. Kiener (1963) depicts the range of this species as extending from the Manbanjeba River southward to the Betsiboka. However, the actual extent of its former range is a matter of some uncertainty, as Keiner appears to have confused this species with P. maculatus up until the formal description of that species in 1966. Certainly his account of the life colors of P. dami (Kiener, 1963) makes no allusion to the spectacular red and black bicolor pattern of sexually active adult specimens illustrated by Nourissat (1993b), while the black and white illustration purporting to represent this species displays the large humeral blotch characteristic of P. maculatus. Malagasy fishermen on Lake Kinkony to whom we showed color photos of P. dami in 1993 described it as a northern species never taken in the Betsiboka, Kamoro, or Mahajamba River basins. These observations accord well with those of Nourissat (1992; 1993a), who found this species at several locations in the Ankofia River basin but neither in the Sofia, the next river to the south, nor anywhere within the Kamoro and Betsiboka drainages.
Nourissat found the bicolor damba to be reasonably abundant at several localities in the Ankofia basin and de Rham (in press) reports its presence in several small lakes in the lower Manbanjeba drainage. This stands in contrast to the situation on Nosy Be. Efforts to secure specimens of this species from its type locality in 1994 proved completely unsuccessful. Local fishermen shown color photos indicated that like Paratilapia polleni, P. dami was still present on the island but had become extremely rare. Specimens brought back to France appear to have adapted well to life in captivity, but to date have bred neither in large aquaria nor in outdoor ponds (Nourissat, pers. comm.). Hopefully future efforts will prove successful. -In any event, its striking adult coloration assures that attempts to secure additional founder stock and to breed the bicolor damba will continue on both sides of the Atlantic.
Paretroplus petiti Pellegrin 1929 appears to have had the most extensive range of any damba species native to Madagascar's western versant. Kotso, as this species is known to the fishermen of Lake Kinkony, was found from the Manambaho River northwards to the Ankofia (Kiener, 1963). Nourissat (1993a) found this species present in small numbers in Andropongy, a small lake in the Ankofia basin. Kotso can also still be found in Lake Kinkony (Nourissat, 1992). According to Malagasy fishermen interviewed in 1993, P. petiti no longer exists in any of the numerous small lakes of the lower Betsiboka or Kamoro basins, while neither Nourissat nor we encountered it in any of the lakes of the lower Sofia basin near the town of Port Berge. There are no current data on the status of P. petiti in the extreme southern portion of its range, an area effectively inaccessible by road.
This attractively colored species reaches 30.0 cm SL and was formerly the basis of a large commercial fishery in Lake Kinkony. The present fishery in that lake is dominated by two introduced tilapias; kotso, while still taken by fishermen, has become extremely rare. Some idea of its present situation may be gauged by the outcome of our efforts to secure breeding stock of this species in 1993. We engaged the services of a team of six fishermen to work a 40 m beach seine for us. At the end of four hours of effort, their catch consisted of eleven P. petiti, two P. kieneri, and ten kilograms of tilapias! Eotso collected from Lake Kinkony have bred successfully in Florida, a most encouraging turn of events in view of this species' tenuous situation in nature.
Paretroplus kieneri Arnoult 1960 is also widely distributed, ranging from the Mahavavy River northward to the Ankofia. Kotsovato [= stonecolored kotso] grows to 20.0 cm SL and is somewhat more slender-bodied than the other three Paretroplus species with which it coexists. Its juvenile color pattern is strikingly reminiscent of the Malawian haplochromines of the genus Nimbochromis. Nourissat (1992) collected an oligomelanic individual of this species from Lake Kinkony, which suggests that this population is polymorphic with regard to coloration. Notwithstanding its rather unflattering Malagasy name, the color pattern of even normally pigmented P. kieneri incorporates substantial patches of yellow-orange on the flanks. Like P. dami, this species occurs in both still and flowing waters (Nourissat, 1992; 1993b) and appears to have the highest tolerance of any damba species for environmental perturbation (Kiener, 1963). This may explain why kotsovato was the first damba bred in captivity, having successfully adapted to outdoor ponds in both southern France and Florida (Nourissat, 1992; Morris, pers. comm.).
Paretroplus maculatus Kiener and Mauge 1966 presently has the most restricted distribution of any described damba species. Published accounts suggest that this species was formerly widely distributed in lakes throughout the lower Betsiboka River basin and abundant enough to support a major fishery (Kiener, 1963). Fishermen in the town of Sarodrano shown photographs of P. maculatus in 1993 indicated that this distinctive damba was formerly to be found in the lakes of the lower Sofia River drainage as well. Today, the species can be found together with P. kieneri in Lake Ravelobe and in two other small lakes within the Ampijoroa Forestry Station, where Roy Morris .and I collected it in 1993. Nourissat (1992) reports the persistence of a population large enough to sustain commercial fishing in several small lakes somewhat to the northeast of Ampijoroa near the town of Maevatanana. The spotted damba is presently being maintained in both France and Florida. Morris (pers. comm.) reports that a pair was observed tending eggs in the summer of 1993, but no fry resulted from the spawning. Subsequent spawning efforts in 1994 proved completely successful. Given the alarming contraction of this species' range over the past thirty years, it is greatly to be hoped that captive breeding efforts will continue to prove productive.
The pinstripe damba, Paretroplus menarambo comes from Lake Sarodrano discovered by Jean Claude Nourissat and his companions in 1992. Its overall morphology and several features of its color pattern suggest it is the sister species of P. maculatus. It is possible that this species once enjoyed a much wider distribution. Fishermen on Lake Kinkony to whom Roy Morris and I showed color photos of this species immediately recognized it and told us that it formerly occurred within the lake. This species is at present clearly restricted to the lower Sofia River basin and de Rham's suggestion (in press) that this species should be found in a number of lakes between the towns of Manpikony and Port Berge appears to have been excessively optimistic. We visited two such lakes on the advice of informants from the town of Sarodrano, only to be told by local fishermen that their catch now consisted chiefly of tilapias and no pinstripe damba had been caught for several years prior to our visit. It would thus appear that this Paretroplus is now restricted to a single lake, where it is by no means abundant (Nourissat, 1993a). The pinstripe damba is presently being maintained on both sides of the Atlantic. Fish held in ponds in Florida spawned successfully in the summer of 1994, a most encouraging turn of affairs given the parlous condition of this species in nature.
The lamena, whose name signifies red fish in the dialect of the Tsihimety people, is a spectacularly colored rheophilic cichlid discovered quite unexpectedly in 1991 by Nourissat and his companions in the Mangarahara, a tributary of the upper Sofia River, ca. 20 km northwest of the town of Mandritsara (Nourissat, 1992). Nourissat (1993b) and de Rham (in press) have suggested that this rapids dwelling species merits a genus of its own. In point of fact, no trenchant structural differences separate the lamena from the genus Paretroplus. Indeed, this species differs from the lake-dwelling damba far less than do rheophilus and lotic representatives of the Neotropical genus Theraps. Hence the decision to treat the lamena as an undescribed Paretroplus species.
The range of this species remains to be precisely defined. All existing collection sites are within the Sofia River drainage. However, there is reason to believe that the lamena has (or more probably once had) a much broader distribution. Nourissat (1993a) showed living specimens of the lamena to villagers living along the banks of the Anjingo River, a tributary of the Ankofia, the next drainage to the north of the Sofia. They immediately recognized the fish, which they declared native to the Anjingo. Roy Morris and I showed colored photographs to fishermen on the shores of Lakes Sarodrano and Kinkony. To our considerable surprise, they also recognized the fish and indicated that while extremely rare, it was present in the streams flowing into these two lakes. As Lake Sarodrano lies in the lower Sofia basin, the presence of the occasional stray lamena in its affluent streams is perhaps to be expected. Lake Kinkony, on the other hand, lies several hundred kilometers west of the nearest tributary of the Sofia River. The headwaters of the Mahavavy River, in whose drainage basin it lies, rise over 200 km to the south of those of the Sofia, from which they are separated by a significant range of mountains. In light of this, I would be inclined to consider this a case in which the lamena had been confused with the goldfish, another widely distributed exotic. However, our informants clearly distinguished between trondro gasy vazaha [= the foreign red fish] and trondro gasy malagasy [= the Malagasy red fish] and in so doing made it clear that they could distinguish unambiguously between a cyprinid and a cichlid.
This species has been bred in both Europe and the United States. De Rham (1995a; 1995b) has reported on a successful spawning of the lamena under aquarium conditions and described its male dominated parental care. While market forces will doubtless spur efforts to bring the lamena into commercial production, what is known of the natural history of this species suggests that establishing a managed population is not immediately crucial to its survival. By virtue of its habitat preferences, the lamena enjoys effective immunity from the depredations of the introduced snakehead (Channa striata), a species ill-adapted to life in swiftly flowing waters. To what extent (if any) the numerical dominance of hybrid Oreochromis in the Ambomboa River has affected it is unknown. The greatest threat to the persistence of the lamena is the physical alteration of its habitat brought upon by erosional sedimentation. This in turn is a direct consequence of continued deforestation within the watershed of the Sofia. While existing trends in this regard hardly admit of optimism, the fact remains that the lamena is presently at substantially less risk than most of its lotic congeners.
Do Madagascar's Cichlids Have A Future?
It should by now be obvious that even a compulsive gambler would think twice before betting the ranch on the long-term survival of most Malagasy cichlids. Two species are in all likelihood extinct (Table 1), while if the remaining eighteen fell under the jurisdiction of the United States' Endangered Species Act, five would be classified as endangered, three as threatened and eight as warranting special concern. In this respect, the cichlids of Madagascar exemplify all too well the status of the island's entire ichthyofauna. Table 2 represents the results of recent collecting efforts analyzed by geographic region. Table 3 looks at the same data from the perspective of habitat type. The picture they present is bleak. Native fishes have effectively been eliminated from the central highlands of the island and are barely holding their own in the coastal lowlands. The persistence of native fishes in estuarine habitats, as revealed in Table 3, makes it tempting to lay the entire blame for this situation upon the impact of exotic predators and competitors. However, the equally strong association between the persistence of native fishes and the presence of some sort of forest cover argues against accepting such a simplistic explanation.
|REGION||NATIVES ONLY||NATIVES & EXOTICS||EXOTICS ONLY|
In point of fact, the freshwater fishes of Madagascar face two distinct but complementary threats to their survival. The first is habitat degradation due ultimately to massive deforestation. Although its effects may not be immediately obvious, the disappearance of forest cover can prove as devastating for fish and other aquatic organisms as for lemurs, parrots, and chameleons. Fish that depend upon a steady drift of insects from the canopy, such as the various Bedotia species, will obviously disappear simultaneously with the riparian forest. However, the repercussions of slash-and-burn cultivation and clear-cut logging in a stream's watershed extend far beyond the consequences to its guild of insectivores.
The first of these is a dramatic increase in silt burden as tropical rains wash soil from denuded hillsides. Silt is a gill irritant and persistent high levels of suspended soil can impose a serious physiological burden upon the fish exposed to it. Erosional siltation can disrupt the reproductive cycle of fishes by smothering their developing eggs or covering their preferred spawning sites too deeply to be dug clear. More insidiously, erosional siltation smothers established communities of benthic organisms with devastating effect upon aquatic food webs. In the most extreme case, erosional siltation can result in total loss of fish habitat by completely filling in a lake, a process exemplified by the fate of Lake Alaotra. Formerly Madagascar's largest lake, Alaotra is now well on its way to becoming a swamp.
The second detrimental consequence of deforestation is a marked increase in the seasonality of stream flow. Intact forest functions as a sponge, storing water during the rainy season and releasing it slowly during the dry. In tropical climates characterized by markedly seasonal precipitation, such as that along the western versant of Madagascar, a stream with a forested watershed will flow more or less strongly year around. Its watershed denuded, a river that flows torrentially during the rainy season will (under the best case scenario) turn into a series of stagnant pools linked by a trickle of water during the dry. Smaller streams typically become intermittent, drying out completely during the dry season.
The effects of such habitat alterations on fish that have evolved under more stable conditions are devastating. Species adapted to small streams, such as killies and rainbowfishes as well as the juveniles of many larger fishes, suffer from increased predation when habitat contraction forces them into main channel habitats. They may in consequence disappear completely from the regional ichthyofauna. Those characteristic of larger rivers must deal with often dramatic seasonal variation in such parameters as dissolved oxygen, turbidity, and temperature. Such changes may not in themselves prove immediately life-threatening to individual fish. However, they significantly increase the level of environmental stress with which they must contend and in so doing may well compromise their ability to reproduce successfully.
Most cichlids are characterized by considerable physiological plasticity. It is not improbable that given sufficient time, most Malagasy species might well adapt to these environmental changes and in so doing come to terms with their dramatically modified environment. However, in their attempts to establish in Madagascar the integrated systems of rice and fish production developed by farmers in northern Italy and Indochina, the French and their Malagasy successors all too successfully naturalized a suite of exotic species far better adapted to life in chronically disturbed habitats than any native cichlid. That two representatives of the portmanteau biota are voracious carnivores has certainly accelerated the declines of native species, though their absence would not in all likelihood alter the eventual outcome of this unplanned experiment in evolutionary ecology. In effect, human intervention has altered the rules of the evolutionary game for Madagascar's native fishes, then introduced a team of superior competitors.
The presence of these exotics seriously constrains any efforts to conserve natural populations of any Malagasy cichlids. In situ conservation of terrestrial organisms essentially entails locating a piece of relatively intact habitat and protecting it from further human impact. In a country such as Madagascar, such an exercise must often confront formidable obstacles. However, these are essentially socioeconomic in nature. Given sufficient political will and funding, they can be surmounted. Such an approach holds some promise of success on Nosy Be, where exotic piscivores have yet to be established, but is effectively precluded on Madagascar proper, where undisturbed aquatic habitats are virtually non-existent and exotic species are effectively ubiquitous. Habitat restoration is not presently a workable conservation option because once established in a given drainage, an exotic is ineradicable by any means currently available. Recent advances in the field of genetic engineering suggest that this may not always be the case, but in the near term, most Malagasy cichlids will either survive under some form of management or they will not survive at all.
Ideally, captive breeding programs should be undertaken by the Malagasy themselves. Given the magnitude of Madagascar's socio-economic problems however, this is hardly a realistic scenario. Saving biodiversity for its own sake is not a political imperative for a country with a mean per capita annual income of $200.00, a stagnant economy, and a rate of population growth of roughly 3.0% per annum.
Under such circumstances, any conservation program that does not pay its own way will receive very short shrift indeed. It is largely because foreign tourists are willing to spend considerable sums of money to see them in the wild that lemurs, chameleons, and butterflies have vocal and increasingly influential advocates within the Malagasy political establishment.
Regrettably, the Malagasy freshwater fish fauna, unlike those of Lakes Malawi and Tanganyika, will never drive ecotourism in this manner. As the Malagasy do hold many of their native fish in high culinary regard, the possibility that such cichlids as marakely, trondro mainty, and the several dambas might be someday cultured for food is certainly worth exploring. However, a great deal of hands-on research must be undertaken before either the technical or the economic feasibility of such an effort can be evaluated in a realistic manner. Such pilot studies take time and cost money, both in short supply. Thus in the near term, in situ captive breeding is unlikely to play a major role in saving even the few Malagasy cichlids with some aquaculture potential.
For the immediate future, ex situ efforts offer the only real hope for those representatives of the Malagasy fish fauna amenable to captive breeding. There is certainly ample precedent for such a project. Zoos have already played an important role in efforts to save many of Madagascar's critically endangered terrestrial animals, while the Association of Zoos and Aquariums has formally sanctioned a Species Survival Program for the endangered cichlid fishes of Lake Victoria. Several AZA member institutions are already devoting space to the husbandry of Malagasy fishes and a number have expressed interest in organizing a comparable SSP for this endangered ichthyofauna. A formal institutional breeding program for these fishes will almost certainly be established within the next few years.
Because of their institutional character, such programs enjoy a considerable degree of stability and can draw upon a substantial body of expertise in the genetic management of small populations. However, it is questionable whether such unaided efforts can adequately address the challenge of preserving all of Madagascar's endemic cichlids, much less the entire Malagasy ichthyofauna. Institutional space and manpower are finite and Madagascar is not the only corner of the world whose fishes have a legitimate call on these limited resources. Maintaining a captive population of any species large enough to guarantee against the erosion of genetic variability under these circumstances will not be a simple matter. Finally, while it is possible to design breeding programs to minimize this hazard, life under aquarium conditions over many generations can exert subtle but powerful influences on a species' genome. The risk of unintentional domestication is real.
I would argue that amateur aquarists can play an important role in the ex situ conservation of Malagasy cichlids. The most obvious way an individual hobbyist can support such conservation efforts is as a participant in an institutional captive breeding program. The Aquatic Conservation Network, an association of serious hobbyists committed to preserving global aquatic biodiversity, is presently creating administrative structures that will allow competent amateur breeders to effectively collaborate with zoo and aquarium professionals in implementing such undertakings. However, participation in an SSP entails a long-term commitment to working with a limited number of species. The experience of such specialty groups as the American Killifish Association with species maintenance programs suggests that few aquarists are either willing or able to make such a commitment.
Fortunately, there is yet another way for hobbyists to participate in the ex situ conservation of Malagasy cichlids. Commercial breeders of ornamental fishes have the ability and resources to produce these fish in numbers in excess of the largest population that could ever be maintained under institutional auspices. Those aquarists who opt to purchase domestically-bred specimens of Malagasy cichlids are thus making a positive contribution to their survival, for given sufficient interest in a given species, market forces will provide all the stimulus necessary for fish farmers to produce it on a continuing basis. Assuming a reasonable number of founder individuals, such a population would be effectively buffered against accidental loss of genetic variability. Equally important, most of these fish would be pond-bred. While a fish pond in Florida is also an artificial environment for Malagasy cichlids, such an outdoor setting certainly has more in common with their native habitat than an aquarium.
Because these species are certain to vary significantly in their appeal to hobbyists, commercial and institutional captive breeding programs represent complementary approaches to their ex situ conservation. However, aquarists should bear in mind that every species soundly established among the ranks of ornamental fishes is one less competing for space and funding in an institutional program. Obviously many factors enter into the decision to acquire a new fish. I suggest the time has now come for a hobbyist to consider its conservation status along with such factors as adult size, behavior, and water preferences before deciding to work with a given species. If enough readers share this point of view, there may indeed be some hope for the cichlids of Jurassic Park.
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© Copyright 1998 Paul V Loiselle, all rights reserved
Loiselle, Paul V. (Juli 02, 1998). "The Cichlids of Jurassic Park". Cichlid Room Companion. Abgerufen am Dezember 06, 2019, von: https://cichlidae.com/article.php?id=97&lang=de.