Chapter 9 Fishes

Chapter 9 Fishes Introduction to the Freshwater Fishes J. S. Sparks and M. L. J. .Stiassny Alrhough many of Madagascar's rcrrestrial vertebrares have knowledge persist. Finally, in the face of the current rate of been studied in great decail, parricularly the lemurs, very aquatic habitat degradation in M·adagascar, we present our little up-to-date information is availa ble for the highly vicw of the future of the island's freshwater ichthyofauna. threatened freshwater fishes native to the island. This intro In many ways Madagascar possesses a typical island duction provides a summary of Madagascar's native fresh ichthyofauna, but it is also one that differs in certain re water fishes and an update on the current state of knowl spects because of its continemal (Gondwanan) origin. Like edgc regarding the origins, composition, biogeography, those of many true oceanic islands, Madagascar's na and relationships of this ali but neglected vertebratc buna. tive ichthyofauna is relatively depauperate at broad taxo We do not attempt a summary of the hydrology, limnology, nomie levels when compared with those of much larger, or conservation status of Madagascar's aquaric resources geogmphically more diverse continentallandmasses (table here, as these have bcen presented in detail elsewhere 9.1). However, bascd on the revised totals presented herein (e.g., Battistini and Richard-Vindard 1972; Chaperon et al. and considering the surface arca of the island, the notion of 1993; Riseng 1997; Wright 1997; Benstead et al. 2000). a depauperate ichthyofauna at the species leve! for Mada Herein wc focus on patterns of fish diversity and distribu gascar is no longer tenable (e.g., Kiener 1963; Kiener and tion and the historical geological events that have shaped Richard-Vindard 1972; Jenkins 1987). In fact, Madagas them. car's freshwarer fish fauna is shown to be numerically fully To interpret the origin(s) and current composition of the in line with those of other landmasses of similar size and ichthyofauna in a useful way, we need not only information supports more or Jess cxacdy as many species as would be on the phylogenetic affinities of the groups present but also predicted given the island's surface area of nearly 600,000 knowledge of their distributions in space and ti me. We sum km2 (fig. 9.1; MacArthur and Wilson 1967; Brown and marize both historical and recent survey data and attempt Lomolino 1998). to synthesize these and current phylogenetic hypotheses in In contrast to many othee island systems and owing ro order to provide a contextual overview of the island's fresh its continental origin, Madagascar, isolated since. the Creta water fish faur}a. Comrary to a commonly expressed belief ceous (Storey 1995; Hay et al. 1999), is home to small radi (e.g., Grandidier and Petit 1932), Madagascar's freshwater ations of freshwater fishes thar do not readily enter marine fishes are not well known, and phylogenetic relationships of habitats. Many taxonomie groups with members present only a few groups have been investigated to date. We docu on the island have broad Gondwanan distributions and ment this low leve! of knowledge and discuss possible rea rhus rich potential to provide insighr into the past connec sons for it, as weil as how our understanding of this fauna tions of the southern continents. In sharp contrast, othee has advanced over the past decade and where gaps in islands of the region, such as the Comoro Islands and 849 850 Fishes Introduction 10000 w 1965; Kiener and Maugé 1966; Kiener and Richard Vindard 1972), and by the carly part of the past cenrury most biologists had concluded chat the ichthyofauna of Madagascar was weil known (e.g., Grandidier and Petit 1000 IS ... 1932). However, beyond lists of species known at the time, 1 10 .. for the most part little additional information on the is a:l land's fishes was reported in this literature. Notably lacking 100 was information on !ife history, reproductive biology, and t"' $1. cu Il relationships of the native fishes and their patterns of dis ! NZ MDl tribution both within Madagascar and regionally. ln fact, despite a literature going back 150 years, it is remarkable 10 how little we still know about the majority of Madagascar's .. freshwater fishes . Perhaps as a result of this lack of knowledge, Madagas 10' 10' ,,. 10' ,,. car's fishes have not been a mainstream focus for efforts of At•• (km') conservation organizations or government agencies, and in the design of protected areas native fishes have traditionally Figure 9. 1. Species-area relatiooships for the reported number of native fresh water fish species from MadagaS(ar and ether continental and oceanic land been neglected. Furthermore, larger rivees are frequently masses (modified alter Riseng 1997). Relationships are shown indicating the in used as reserve boundaries, which does little to prorect the crease in the number of freshwater fish species recorded from the fresh waters of integrity of the river itself. An exemplary exception is the Madagascar over the past three decades (symbols MO 1-MD4). Totals for Mada gascar are shown correspondin<) to the number of native freshwater species re recendy designated Parc National (PN) de Masoala in ported in this study (MD• •: 143 spp.); the number of endemie freshwater spedes northeastern Madagascar (Kremen et al. 1999). The PN de recorded in this study (MOe: 93 spp.); and the number of endemie species re corded by Kiener and Maugé {1972, MOt: 32 spp.), Stiassny and Raminosoa Masoala was designed to indude river basins within its bor (1994, M02: 42 spp.), de Rham (1996, M03: 49 spp.). and Benstead et al. (2000, ders specifically to protect native fish communities. Possibly M04: 58 spp.). Abbreviations (references for species tetais used to compile this another reason for a continued terres trial bias is the sad fact figure Jisted in parentheses): Af = Alrica (Caget et al. 1984, 1986; Skelton 1990; lundberg et al. 2000); AS .. Australia (Allen 1989; Pellard et al. 1990; McOowall that today few areas of the island remain where intact na 1996); B = Bornee (M. Kottelat (pers. comm.l records 394 species from Bornee tive fish communities persist. Exotic species, especially eila· (shown] and estimates that there are now approximately 450 described species (not shownJ; Inger and Kong(1962] report 290 species from western Bornee (not piine cichlids introduced for aquaculture purposes, are shownD; CU-= Cuba (SS(shownl recorded by Alayo (19731 and 36(not shawn} ubiquitous in ali but the most remote regions of the island by Vergara (1980}); Hl = Hawaii (Fitzsimons and Nishimoto 1990); lM = Inde (j. Sparks and K. Riseng unpubl. data), and the degree of Malay archipelago (Zakaria-lsmail 1994 (minimum estimateJ; Kottelat {19981 states that approximately 1000 species are known from western lndonesia (not habitat degradation and destruction in Madagascar has shawn )); IS = lndian subcontinent (Ta lwar and Jhingran 1992); NA= North Amer been, and continues to be, severe (Benstead et al. 2000). ica (Williams and Miller 1990; lundberg et al. 2000); NG = New Guinea (Munro The paucity of information on Madagascar's freshwater 1967; Allen [ 1991 J records 320-350 species including sorne estuarine forms (not shownlJ; NZ =New Zealand (McOowall 1990); SA ~ South America (Moyle and fishes, and the Jack of consideration they have received from Cech 1996; Vari and Malabarba 1998); SL =Sri Lanka (Pethiyagoda 1991); and conservationists, are certainly also attributable to the inac w = wocld (Stiassny 1996; Lundberg et al. 2000). Geographie areas obtained from Rand McNally Universal World Atlas (1987).• cessibility of many of the island's river basins and the dif ficulties associated with the conservation of river systems in general (Boon et al. 2000). Most of Madagascar's protected Mascarenes (which are of recent volcanic origin, 15 million areas are very small, frequenrly consisting only of a small years ago [Ma] or less) and the granitic Seychelles (ancient forest fragment surrounded by an expansive deforested re Gondwanan fragments isolated since approximately the gion. Under such circumstances, at very best only a few Late Cretaceous [Plummer and Belle 1995; Storey 1995]), headwater streams can be afforded any protection. Unfor have extremely depauperate fish faunas dominated by ma tunately, headwater regions do not harbor diverse fish as rine colonizers or species with !ife histories dependent semblages and as such are not the habitats most în need of on marine habitats, such as gobies, eleotrids, ambassids, protection from the perspective of maintaining ichthyolog eels, and mullets (Bennett 1830; Bleeker and Pollen 1875; ical diversity. Teugels et al. 1985). lt has long been recognized that Madagasca r is charac An extensive literature on Madagascar's freshwater terized by a highly endemie freshwater ichthyofauna, but fishes datesfrom the mid-1800s (e.g., Bleeker 1868; Bleeker historically this fauna has been viewed as notably species and Pollen 1875; Sauvage 1891; Grandidier and Petit 1932; poor. Calculations based on prior estimates of species rich Pellegrin 1933; Bertin 1948; Arnoult 1959; Kiener 1963, ness suggested that Madagascar was home to only about J. S. Sparks and M. l. J. Stiassny 851 Table 9. 1. Checklist of native Malagasy freshwater flshes and their regions of occurrence Conservation Southern Western Northwestern Eastern Eastern Taxon status basins basins basins highlands lowlands Anguillidae Anguilla bicolor s x x x x x A. marmorata s x x x x x A. mossambka s x x x x x Clupeidae Pellona ditche!a u x x x Sauvage/fa madagascariensis s x x x S. nov. sp. *robustaH u x Spratellomorpha bianafis u x x Ariidae Arius afrkanus s x x x A. dussumieri u x x A. madagascarlensis T x x A. nov. sp. *ankofia* T x A. nov. sp.

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