Coelecanth - Latimeria chalumnae
The coelacanth is possibly the sole remaining representative of a once widespread family of Sarcopterygian (fleshy-finned) fish that were common from 280-100 mya, and were distributed throughout the globe. More than 120 species are known from fossils, and the family was thought to have become extinct during the K-T extinction event, 65 million years ago. Coelecanth were first identified from an English fossil by naturalist Louis Agassiz in 1836 and became known as a distinct taxonomic group in 1844. Two species of coelacanth are alive today, the western Indian Ocean species Latimeria chalumnae, and a more restricted Indonesian species, L. menadoensis.
History - In 1938, a living coelacanth was discovered by Marjorie Courtenay-Latimer among specimens in a trawler that had been fishing off East London, South Africa, in the southern WIO. This fish was described by J.L.B. Smith in an atmosphere of scientific excitement, skepticism and doubt. The media considered this to be the zoological discovery of the century. Up till the 1980s coelecanth were still only known from a few locations in the SWIO, with the best-known populations found in the Comoros, where fishermen were familiar with this unusual fish caught in deep-set lines. By the end of the 20th century, the fish was known to be widespread in the WIO, with the northernmost record from Malindi, Kenya, and significant populations in northern Tanzania, several of the Comorian islands and southern Mozambique/northern South Africa. As diving technology has improved, live observation or coelacanths has become possible – first from the submersible GEO, in 1987, and more recently on rebreather diving units, from November 2000.
Threats - The primary threat to coelacanth is demersal fishing on the continental shelf, between about 100 and 400 m. In Comoros, this was primarily using artisanal gears historically, so development of more mechanized fisheries, using motors for offshore fishing, resulted in decreased coelacanth catch in the 1960s. However with increasing numbers of fishers, and greater use of deep gill nets such as in Tanga, Tanzania since 2000, large numbers of coelacanth have been caught from previously unknown populations. The larger numbers reported are also likely due to a greater awareness of the significance of coelacanths, and improved communications, such that catches that might have gone unnoticed previously are now brought to the attention of authorities. Nowhere, however, is there an indication that coelacanths exist in large aggregations.
Conservation - The coelacanth is listed as Critically Endangered on the IUCN Red List, and in Appendix 1 of CITES. The Comoros has been the epicenter of coelacanth conservation from the 1970s onwards, with the most comprehensive efforts to both study and design conservation measures appropriate to this unusual fish. The discovery of coelacanths within the World Heritage Site iSimangaliso in 2000 emphasized the precautionary value of protecting critical sites of high biodiversity value. Since 1987 the Comoros has been the epicenter of coelacanth conservation efforts, led by Dr. Hans Fricke and supported by the Frankfurt Zoological Society and others. In 2002 the African Coelacanth Ecosystem Programme (ACEP) was initiated taking on a trans-frontier, ecosystem based approach to science and management of the coelacanth, with a particular focus on depths between 40 – 1000m in the Mozambique Channel and north to Kenya. In Tanga, Tanzania, the catch of over 30 coelecanth in the decade from 2000 - 2010 led to the formation of the Tanga Coelacanth MPA. Exploration and observational research, conducted by manned submersibles and ROVs, will continue to play a major role in coelacanth studies, alongside biotelemetry, underwater recording systems and physiological probes in order to answer elusive questions.
Key References - Agassiz (1844); Erdmann (2006); Forey (1998); Fricke and Hissmann (1994); Fricke et al. (2000); Fricke et al. (2011); Green et al. (2009); Heemstra et al. (2006); Nikaidoa et al. (2011); Plante et al. (1998); Scott (2006); Smith (1939); Smith (1953); Smith (1956). --> References