Sea Caves to be Explored – The Lair of the Coelacanth

A joint French and South African expedition is setting out today to attempt to learn more about the elusive Coelacanth, a fish once believed to have died out with the demise of the dinosaurs and is often referred to as a “living fossil”.  Whilst the term “living fossil”, a phrase once popular with academics during the 19th and 20th Centuries, may be out of favour with many scientists today, after all, it implies that some species stop evolving and remain unchanged for millions of years, the Coelacanth remains a truly remarkable fish.  However, very little is known about the habits and behaviour of this relatively deep water predator.

The team, a joint expedition of the French National Museum of Natural History (Paris) and the South African Institute for Aquatic Biodiversity intend to explore a series of deep water caves off the east coast of South Africa (Sodwana Bay) which is where a population of these ancient types of fish are believed to live.  Just like a military operation, the expedition has been given a code name – “Gombessa”, the local name for the Coelacanth in fishing communities of the Comoros Islands and the KwaZula Natal coast.

Coelacanths belong to a group of lobe-finned fish known as the Actinistians, part of the larger Sarcopterygian clade, which includes lobe-finned as well as lung-fish.  These fish originated during the Devonian geological period and some of the earliest Coelacanth specimens from the fossil record date to around 375 million years ago.  The Coelacanths were thought to have become extinct with the last known fossil genus Macropoma at the end of the Cretaceous period some 65 million years ago.  A Coelacanth was caught off the coast of eastern South Africa in 1938, this caused a sensation.  A trawler boat fishing off the Chalumna river estuary caught a bizarre looking fish in its nets and once the vessel had returned to port, the curator of a nearby museum was notified and it was from her notes and sketches that led to this specimen being identified as a Coelacanth.

A Picture of the Coelacanth Caught in 1938

The discovery of the Coelacanth in 1938.

The discovery of the Coelacanth in 1938.

Picture Credit: Sciencecases.org

Occasionally, these fish are caught by fishermen, catches have been made off the Comoros Islands and other deep water channels off the coast of east Africa.  A second species has been discovered in the waters surrounding Indonesia.  It has been speculated that other populations and species may exist but as these fish live in depths of more than one hundred metres and seem to be mostly active at night, very little exploration of likely habitats has actually been undertaken.

The “Gombessa” expedition intend to dive around the Jesser Canyon, a relatively deep, sea-water trench in Sodwana Bay.  There are  caves in this area and it is thought that these fish, some of which can grow to more than 1.5 metres in length may lurk in the caves, using them as lairs to hold up during the daytime before venturing out to hunt at night.  The first Coelcanth caught on film was one that was filmed by a BBC Natural History Unit, which happened to be in the Comoros filming for the ground breaking BBC television series, narrated by David Attenborough called “Life on Earth”.  The camera crew were alerted that a Coelacanth had been caught and it was still alive.  The team were able to get some footage of the creature the following morning,  but it was very weak and near death.  More recently some footage of Coelacanths has been shot during deep water dives.

This new expedition will attempt to film these animals in their natural habitat using low intensity light cameras.  They plan to take three dimensional moving images of the strange fins of these creatures, perhaps proving or disproving once and for all whether or not these fish actually “walk on their fins”.  The team will also attach harmless acoustic tracking devices so that they can track their movements and learn about where these prehistoric fish go.

The Coelacanth is an example of a “Lazarus taxon”, an organism once thought to have died out only to be found living in modern times.  Recently, Coelacanth numbers have been causing concern, extensive dredging and pollution in the waters of eastern Africa as the area is developed for commercial shipping in conjunction with increased fishing may have led to a reduction in the Coelacanth population.  The expedition will be working over the next few weeks to try to learn as much as they can about this peculiar fish, in the hope that the knowledge gained may help with their conservation.

Commenting on the scientific importance of the Coelacanth (Latimeria), John F. Graf, a palaeontologist at the Southern Methodist University (Dallas, United States), stated:

“What makes the Coelacanth interesting is that they are literally the closest living fish to all the vertebrates that are living on land.  They share the most recent common ancestor with all of terrestrial vertebrates.”

In 2010, those clever people at Safari Ltd introduced a wonderful Coelacanth replica into their Wild Safari Dinos model series.  The model measures a little over sixteen centimetres in length and it is painted a vivid blue.

The Wild Safari Dinos Coelacanth Replica

Ancient fish model - Coelacanth

Picture Credit: Everything Dinosaur

The model is a very accurate depiction of a Coelacanth, the white dots on the model are typical of those seen on extant Latimeria.  One of the things the expedition hope to find out is what the dots are for, as all the specimens caught to date have their own unique white markings.  The model depicts the bizarre fringed tail, made up of three distinct lobes perfectly and it is a super detailed replica of a creature which we can trace its origins back to the Devonian.

A spokesperson from Everything Dinosaur stated:

“Diving to depths in excess of one hundred metres can be very hazardous, but the research is desperately needed if we are to understand more about these very ancient creatures.  Data obtained during this expedition could help to protect the existing population and prevent the Coelacanths from becoming effectively extinct for a second time.”

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