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Research | Coelacanth

The Coelacanth, a 'fish caught in time'.

The Coelacanth is an amazing fish. Until its rediscovery by scientists in 1938 (artisanal fishermen probably knew of its continued existence throughout the ages in scattered remote areas) it was thought to have evolved some 400 million years ago and gone the way of the dinosaurs some 65 million years ago; its legacy reduced to fossil record. It is now known as the "living fossil" and is listed as Critically Endangered on the IUCN Red List of Threatened Species and in CITES Appendix I.

The first captured coelacanth was landed in East London, South Africa in 1938, but it was not possible to preserve its soft internal organs and only limited information could be gleaned about its remarkable physiology. To name but a few amazing features; it does not have a backbone, but an oil-filled 'notochord'. It appears to have an electrical receptor in the rostral organ. It has four limb-like appendages, with stubby fins. It has a double tail, very thick at the root. It gives birth to live young, as many as 26 at one time. It is believed to gestate for 14 months and perhaps live for more than 80 years. The young develop inside their mother and are attached to the outside of a huge yolk-filled egg of about 100 mm in diameter. As the embryo develops the sac diminishes in size until it disappears completely.

Due to the likely slow reproduction rate and small number of offspring of coelacanths, the species is possibly particularly vulnerable to the removal of pregnant females from the population.

A dramatic photograph of one of the recent Tanga Coelacanths, showing the four very limb-like lower fins.

Photos above courtesy of Tanga Coastal Zone Conservation and Development Programme.

The world waited some 14 years before the second Coelacanth was discovered, in the Comoros. Then several more were found there, and the fish was photographed and filmed for the first time in its natural habitat. Just as the world was getting used to the idea of living Coelacanths, one turned up in Indonesia (though this is currently thought to be a slightly different species).

Population numbers are particularly difficult to assess given the deep habitat (thought to be around 150-700m) but many believe the Comoros population suffered a strong decline in the 1990s, in part due to the attention they received after their habitat was discovered there. There are serious concerns about 'rewarding' fishermen for reporting and turning in Coelacanths, for fear of encouraging their capture. They are usuallly caught by accident on long bottom lines whilst local fishermen search for other deep water species. The Coelacanth is not good to eat; too oily, apparently.

Another amazing discovery in the recent history of the Coelacanth...

In August 2004, a Coelacanth was caught in a net in relatively shallow water (70m deep) in the Tanga region of Tanzania.

In the following 5 months, a further 18 have been caught and reported from just two small areas in this region.

Why the sudden appearance of these strange fish in this new area?

What's going on?

The Tanga catches have included a very large pregnant female, almost 2m in length and weighing 110 kg.

Below is a close-up of a fertilised egg, with the early-stage embryo clearly visible on the outside.

Photos courtesy of Tanga Coastal Zone Conservation and Development Programme.

For detailed information on the Coelacanth visit the IUCN Red List website, the ARKive website or the 'Dinofish' site.

Tanga

The Tanga Region lies in northern Tanzania, close to the border with Kenya and far from previous known habitats in the Comoros and South Africa. Tanga is an attractive little town with a port, good natural harbour, friendly yacht club and numerous fringing and patch reefs, mangroves, seagrass meadows and estuaries.

About a decade ago the coastal resources were suffering from unsustainable pressures, with declining fish catches, deteriorating condition of the coral reef and reduction of mangroves and coastal forests. Assistance was sought from the IUCN and Ireland Aid to develop a long-term conservation and development strategy, leading to the formation of the Tanga Coastal Zone Conservation and Development Programme.

The Tanga Coastal Zone Conservation and Development Programme (TCZCDP)

The Tanga Coastal Zone Conservation and Development Programme (TCZCDP) has been running since 1994 and is now wrapping up with an exit phase.

The first three years of the Programme were a listening and piloting phase and consisted of participatory socio-economic and resource assessments to identify priority issues. These were addressed in a pilot village in each District, through the formation of village environmental committees.

In the second phase, this approach was spread over a much wider area, and collaborative fisheries management plans were developed by the resource users together with the District authorities. Management areas comprised clusters of villages sharing fishing areas and reefs. Representatives of each Village Environmental Committee form a Central Coordinating Committee which harmonises and coordinates action plans, by-laws, patrols, and other activities for the entire management area. Six collaborative fisheries management plans have now been implemented.

The third phase focussed on mainstreaming the procedures to ensure that the improved coastal management processes, actions and methods were adopted as normal practices, that the capacity of local institutions for coastal management was adequate and that institutional and financial long-term sustainability were developed.

Since the Programme started, there has been a marked improvement in the health of the reefs, the size of fish populations and catches by local fishermen. A number of reefs have been declared as no-fishing areas, through the collaborative management plans. Village monitoring teams survey both open and closed reefs annually, having been trained in simple methods to record coral health and fish abundance. Destructive fishing methods (such as dynamite fishing and beach seining) have declined as a result of collaborative enforcement activities involving the villagers, District Officers and the Navy. The Programme has also launched a number of environmental education activities in schools and youth groups.

For more information about the Tanga Coastal Zone Conservation and Development Programme visit http://www.iucn.org/places/earo/projs/tanga.htm

And then the Coelacanth showed up. Something which the TCZCDP was never designed to manage.

Dramatic new Coelacanth discoveries

On Monday 23 August 2004 the TCZCDP office received a phone call from District Fisheries saying that fishermen in Kigombe had caught a strange fish. Mr Hassan Kalombo (the Senior Fisheries Officer for that district) and Dr Eric Verheij (the IUCN Technical Advisor for the Tanga Programme) went to check the report and found two complete specimens of Latimera chalumnae, commonly known as the Coelacanth.

These fish were caught in a shark net in about 70 meters of water. It shows just how little we know about the diversity of species found in the Indian Ocean and exactly which areas are critical to preserve it, underlining the need for a precautionary approach to protection of habitat and species.

Mr Hassan Kalombo showing Caroline one of the frozen Coelacanths (which barely fits in their freezer!) at the TCZCDP office

There have also been two previous Tanzanian specimens of Coelacanth, found off the shores of Kilwa in southern Tanzania in September 2003 and early 2004; the second caught in a shark net.

The TCZCDP office encourages fishermen to report Coelacanth captures, but is very conscious of the potential for adverse impact if fishermen begin actively fishing for the species. They pay only the bare price for the meat to discourage active fishing for them.

TCZCDP now have special equipment for live release at depth and intend to train fishermnen to use this equipment. TCZCDP will provide photographic equipment to obtain evidence of live release, for which they intend to pay.

Now there have been 19 Coelacanths captured in the Tanga region alone over a period of just 5 months, making it one of the most prolific capture areas in existence.

The TCZCDP are reporting to the Tanzanian National Coelacanth Committee who are the national representatives to the African Coelacanth Ecosystem Programme (ACEP), who are sending a team of scientists on a research vessel with a submersible to Tanga to investigate in March 2005.

So what's happening?

Why, after all these years, are Coelacanths turning up in such large numbers at these two small regions just south of Tanga? The inshore fishermen have not changed their practises significantly, so why are they suddenly catching 19 coelacanths in 5 months? Unless this dramatic catch rate is greatly and quickly reduced, especially when pregnant females are being landed, it can only spell bad news for the recently-discovered local Coelacanth population.

A sketch (not for use as a navigational chart) showing the port of Tanga (in the north), typical inshore netting areas (shown as red ellipses) that might yield Coelacanths and an approximate box indicating offshore trawling areas.

Note that the coast is very steep-to outside the reefs, so that trawlers in over 100m of water depth could be very close to artisanal fisherman operating in only 40m of water depth on the outside of the reef.

The Ministry of Natural Resources and Tourism has just given (27 Jan. 2005) the go-ahead, in response to local community requests, for local communities & regional authorities to begin acting to conserve the area.

There is a tentative connection with bottom trawling operations. TCZCDP have said that prawn trawlers, out of season, have been given trial permisison to trawl outside the 100m contour line just offshore nearby the Coelacanth capture sites. It seems that within a couple of days of trawling activity commencing, one or more Coelacanths turns up in shallow-water bottom nets.

The most tempting, and as yet tentative, explanation proposed by TCZCDP is that the offshore trawling activity is somehow driving the Coelacanths inshore into shallow waters where they are then trapped by the bottom-nets intended for shark. That the Coelacanths are not reported caught by the trawlers may be because they are driven off by the noise of the trawlers and grinding bottom-dragging nets before they are trapped, or perhaps because the trawlers are less assiduous about reporting captures. Fisheries observers are few and far between on these boats, and mustering adequate monitoring resources is always a problem.

So, for now, the sudden flux of incidences remains a mystery. But the potential impact of capturing so many Coelacanths, some female and pregnant, could be devastating to the local population. If ACEP can positively identify the local Tanga Coelacanth habitat, this could provide further impetus to declare a no-fishing zone to protect the local population. If not, there seems little prospect of keeping the trawlers away. How much time do we have?

Meanwhile, what is the TCZCDP office to do with the 9 almost-complete Coelacanths that they have in their custody, not to mention the many huge eggs preserved in alcohol?

Perhaps a non-profit trust fund could be established for the benefit of the Coelacanths and for the protection of both their habitat and the local fishermen's livelihood, funded by contributions from recognised international marine research Institutes and museums who would like one of the specimens.

Down the road, is it too far-fetched to dream of a well-managed eco-tourism operator being licenced by the trust fund to operate small submersibles to increase public awareness and education about these fascinating creatures, thought by many to be the closest living relative to the first fish to step onto land?

A poster, this one displayed in the Tanga International School, alerting locals in KiSwahili to the importance of the Coelacanth, if found.

 

 

 

 

 

 
© JIOQ 2004, 2005
 


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