Latimeria
From Wikipedia, the free encyclopedia
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Latimeria
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Latimeria chalumnae,
Natural History Museum of
Nantes
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Range in red and
violet
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Latimeria is a rare genus of fish
that includes two extant species: West Indian Ocean coelacanth
(Latimeria chalumnae) and the Indonesian coelacanth (Latimeria
menadoensis). They follow the oldest known living lineage of Sarcopterygii (lobe-finned fish and tetrapods), which means they are more closely related to lungfish, reptiles and mammals than to the common ray-finned fishes. They are found along the coastlines of the
Indian Ocean and Indonesia.[1][2] Since there are only two species of coelacanth and
both are threatened, it is the most endangered genus of animals in the world.
The West Indian Ocean coelacanth is a critically endangered species.[3]
Biological characteristics
Latimeria chalumnae specimen, Zoologisk
Museum, Copenhagen
Based on growth rings in their ear bones (otoliths), scientists infer that individual coelacanths may
live as long as 80 to 100 years. Coelacanths live as deep as 700 m
(2300 ft) below sea level, but are more commonly found at
depths of 90 to 200 m. Living examples of Latimeria chalumnae
have a deep blue color which probably camouflages them from prey species;
however, the Indonesian species (L. menadoensis)
is brown.
Coelacanth eyes are very sensitive, and have a tapetum lucidum. Coelacanths are almost never caught in
the daytime, but have been caught at all phases of the moon. Coelacanth eyes
have many rods, receptors in the retina that help animals see in dim
light. Together, the rods and tapetum help the fish see better in dark water.
Coelacanths are opportunistic feeders, hunting cuttlefish, squid, snipe eels, small sharks, and other fish found in their deep reef
and volcanic slope habitats. Coelacanths are
also known to swim head down, backwards or belly up to locate their prey,
presumably using their rostral glands. Scientists suspect one
reason this fish has been so successful is that specimens are able to slow down
their metabolisms at will, sinking into the less-inhabited depths
and minimizing their nutritional requirements in a sort of hibernation mode.
Latimeria chalumnae model in the Oxford
University Museum of Natural History, showing the coloration in life
The coelacanths which live near Sodwana Bay, South Africa, rest in caves at depths of 90 to 150 m during
daylight hours, but disperse and swim to depths as shallow as 55 m when hunting
at night. The depth is not as important as their need for very dim light and,
more importantly, for water which has a temperature of 14 to 22°C. They will
rise or sink to find these conditions. The amount of oxygen their blood can
absorb from the water through the gills is dependent on water temperature.
Scientific research suggests the coelacanth must stay in cold, well-oxygenated
water or else its blood cannot absorb enough oxygen.[4] The fish seems to be very well adapted to its
environment, which is seen as one of the reasons why it has the slowest
evolving genome of all known vertebrates.[5]
Reproduction
Female coelacanths give birth to live young, called "pups", in groups
of between five and 25 fry at a time; the pups
are capable of surviving on their own immediately after birth. Their
reproductive behaviors are not well known, but it is believed that they are not
sexually mature until after 20 years of age. Gestation time is
estimated to be 13 to 15 months.
Discoveries
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Date
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Description
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pre 1938
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Though unknown to the West, the South African natives
knew about the fish and called it "gombessa" or "mame."[8]
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1938
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(December 23) First discovery of a modern coelacanth
30 kilometers SW of East London, South Africa.
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1952
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(December 21) Second specimen known to science
identified in the Comoros. Since then more than 200 have
been caught off the islands of Grand Comoro and Anjouan.
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1988
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First photographs of coelacanths in their natural
habitat, by Hans Fricke off Grand Comoro.
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1991
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First coelacanth identified near Mozambique, 24 kilometers offshore NE of Quelimane.
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1995
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First recorded coelacanth on Madagascar, 30 kilometers S of Tuléar.
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1997
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(September 18) New species of coelacanth found in Indonesia.
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2000
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A group found by divers off Sodwana Bay, iSimangaliso Wetland Park,
South Africa.
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2001
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A group found off the coast of Kenya.
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2003
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First coelacanth caught by fisherman in Tanzania. Within the year, 22 were caught in total.
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2004
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Canadian researcher William Sommers captured the
largest recorded specimen of coelacanth off the coast of Madagascar.[citation needed]
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2007
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(May 19) Indonesian fisherman Justinus Lahama caught a
1.31 meter (4.30 ft) long, 51 kilogram (112 lb) coelacanth off Sulawesi Island, near Bunaken National Marine Park, that
survived for 17 hours in a quarantined pool.[9]
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2007
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First find in South
Africa
The discovery was covered in a 1939 Daily Dispatch article
On December 23, 1938, Hendrik Goosen, the captain of
the trawler Nerine,
returned to the harbour at East London, South Africa,
after a trawl between the Chalumna and Ncera Rivers.
As he frequently did, he telephoned his friend, Marjorie Courtenay-Latimer,
curator at East London's small museum, to see if she wanted to look over the
contents of the catch for anything interesting, and told her of the strange
fish he has set aside for her. Correspondence in the archives of the South
African Institute for Aquatic Biodiversity (SAIAB, formerly the JLB Smith
Institute of Ichthyology) show that Goosen went to great lengths to avoid any
damage to this fish and ordered his crew to set it aside for the East London
Museum. Goosen later told how the fish was steely blue when first seen, but by
the time the 'Nerine' entered East London harbour many hours later, the fish
had become dark grey.
Failing to find a description of the creature in any
of her books, she attempted to contact her friend, Professor James Leonard Brierley Smith,
but he was away for Christmas. Unable to preserve the fish, she reluctantly
sent it to a taxidermist. When Smith returned, he immediately recognized it
as a coelacanth, known only from fossils. Smith named the fish Latimeria
chalumnae in honor of Marjorie Courtenay-Latimer and the waters in which it
was found. The two discoverers received immediate recognition, and the fish
became known as a "living fossil". The 1938 coelacanth
is still on display in the East London, South Africa,
museum.
However, as the specimen had been stuffed, the gills
and skeleton were not available for examination, and some doubt
therefore remained as to whether it was truly the same species. Smith began a
hunt for a second specimen that would take more than a decade.
Comoros
Preserved specimen of Latimeria chalumnae in the
Natural History Museum,
Vienna, Austria (length: 170 cm - weight: 60 kg). This specimen was caught on
18 October 1974, next to Salimani/Selimani (Grand Comoro, Comoro Islands) 11°48′40.7″S 43°16′3.3″E.
A worldwide search was launched for more coelacanths,
with a reward of 100 British pounds, a very
substantial sum to the average subsistence fisherman of the time. Fourteen
years later, one specimen was found in the Comoros, but the fish was no stranger to the locals — in the
port of Domoni on the Comoran island of Anjouan, the Comorians were puzzled to be so rewarded for a
"gombessa" or "mame", their names for the nearly inedible
fish that their fishermen occasionally caught by mistake.
The second specimen, found in 1952 by Comoran
fisherman Ahamadi Abdallah, was described as a different species, first as Malania
hunti and later as Malania anjounae, after Daniel François Malan, the
South African Prime Minister
who had dispatched an SAAF Dakota at the behest of Professor Smith to fetch the specimen.
It was later discovered that the lack of a first dorsal fin, at first thought to be significant, was caused by
an injury early in the specimen's life. Ironically, Malan was a staunch creationist; when he was first shown the primitive creature,
he exclaimed, with a twinkle, "My, it is ugly. Do you mean to say we once
looked like that?"[11] The specimen retrieved by Smith is on display at
the SAIAB in Grahamstown, South Africa where he worked.
The Comorans are now aware of the significance of the endangered species, and
have established a program to return accidentally-caught coelacanth to deep
water.
As for Smith, who died in 1968, his account of the
coelacanth story appeared in the book Old Fourlegs, first published in
1956. His book Sea Fishes of the Indian Ocean, illustrated and
co-authored by his wife Margaret, remains the standard ichthyological reference for the region.
In 1988, marine biologist Hans Fricke was the
first to photograph the species in its natural habitat, 180 metres
(590 ft) off Grand Comoro's west coast.[12]
Second species in
Indonesia
Latimeria menadoensis,
Tokyo Sea Life Park (Kasai Rinkai Suizokuen), Japan
On September 18, 1997, Arnaz and Mark Erdmann,
traveling in Indonesia on their honeymoon, saw a strange fish enter the market at Manado Tua, on the island of Sulawesi.[13] Mark thought it was a gombessa (Comoro
coelacanth), although it was brown, not blue. An expert noticed their pictures
on the Internet and realized its significance. Subsequently, the
Erdmanns contacted local fishermen and asked for any future catches of the fish
to be brought to them. A second Indonesian specimen, 1.2 m in length and
weighing 29 kg, was captured alive on July 30, 1998.[7] It lived for six hours, allowing scientists to
photographically document its coloration, fin movements and general behavior.
The specimen was preserved and donated to the Museum Zoologicum Bogoriense
(MZB), part of the Indonesian Institute of
Sciences (LIPI).[13]
DNA testing revealed this specimen differed genetically from
the Comorian population.[14][15] Superficially, the Indonesian coelacanth, locally
called raja laut (king of the sea), appears to be the same as those
found in the Comoros, except the background coloration of the skin is
brownish-gray rather than bluish. This fish was described in a 1999 issue of Comptes
Rendus de l'Académie des sciences Paris by Pouyaud et al. It was given the scientific name Latimeria
menadoensis.[16] A recent molecular study estimated the divergence time
between the two coelacanth species to be 40–30 mya.[17]
On May 19, 2007, Justinus Lahama, an Indonesian
fisherman, caught a 1.3-metre-long, 50 kg/110 pound coelacanth off the
coast near Manado, on northern Sulawesi Island near Bunaken National Marine
Park. After spending 30 minutes out of water, the fish, still alive, was placed
in a netted pool in front of a restaurant at the edge of the sea. It survived
for 17 hours. Coelacanths, closely related to lungfish, usually live at depths
of 200-1,000 metres. The fish was filmed by local authorities swimming in the
metre-deep pool, then frozen after it died. AFP claim French, Japanese and
Indonesian scientists working with the French Institute for Development and
Research carried out a necropsy on the coelacanth with genetic
analysis to follow. The local university is now studying the carcass.[9][18]
iSimangaliso Wetland
Park in South Africa
In South Africa, the search continued on and
off over the years. A 46-year-old diver, Rehan Bouwer, lost his life searching
for coelacanths in June 1998.
On 28 October 2000, just south of the Mozambique border in Sodwana Bay in the St. Lucia Marine Protected Area,
three deep-water divers, Pieter Venter, Peter Timm, and Etienne le Roux, made a
dive to 104 metres and unexpectedly spotted a coelacanth.
Calling themselves "SA Coelacanth Expedition
2000", the group returned with photographic equipment and several
additional members. On 27 November, after an unsuccessful initial dive the
previous day, four members of the group, Pieter Venter, Gilbert Gunn, Christo
Serfontein, and Dennis Harding, found three coelacanths. The largest was
between 1.5 and 1.8 metres in length; the other two were from 1.0 to 1.2
metres. The fish swam head-down and appeared to be feeding from the cavern
ledges. The group returned with video footage and photographs of the
coelacanths.
During the dive, however, Serfontein lost
consciousness, and 34-year-old Dennis Harding rose to the surface with him in
an uncontrolled ascent. Harding complained of neck pains and died from a cerebral embolism while on the boat. Serfontein recovered
after being taken underwater for decompression sickness treatment.
In March–April 2002, the Jago Submersible and Fricke
Dive Team descended into the depths off Sodwana and observed 15 coelacanths. A dart probe was used
to collect tissue samples.
Tanzania
Coelacanths have been caught off the coast of Tanzania since 2004. Two coelacanths were initially reported
captured off Songa Mnara, a small island off the edge of the Indian Ocean in August 2003. A spate of 19 more specimens of
these extremely rare fishes weighing between 25 and 80 kg were reported
netted in the space of the next five months, with another specimen captured in
January 2005. A coelacanth weighing as much as 110 kg was reported by the Observer newspaper in 2006. Officials of the Tanga Coastal
Zone Conservation and Development Programme, which has a long-term strategy for
protecting the species, see a connection with the timing of the captures with trawling - especially by Japanese
vessels - near the coelacanth's habitat, as within a couple of days of trawlers casting their
nets, coelacanths have turned up in deep-water gill nets intended for sharks.
The sudden appearance of the coelacanths off Tanzania has raised real worries
about its future due to damage done to the coelacanth population by the effects
of indiscriminate trawling methods and habitat damage.[19]
Hassan Kolombo, a programme co-ordinator, said,
"Once we do not have trawlers, we don't get the coelacanths, it's as
simple as that." His colleague, Solomon Makoloweka, said they had been
pressuring the Tanzanian government to limit trawlers' activities. He said,
"I suppose we should be grateful to these trawlers, because they have
revealed this amazing and unique fish population. But we are concerned they
could destroy these precious things. We want the government to limit their activity
and to help fund a proper research program so that we can learn more about the
coelacanths and protect them."[19]
In a March 2008 report,[20] the Tanzania Natural Resource Forum, a local
environmental nongovernmental organization, warned that a proposed port project
at Mwambani Bay could
threaten a coastal population of coelacanth.[21]
References
1.
^ Holder,
Mark T.; Erdmann, Mark V.; Wilcox, Thomas P.; Caldwell, Roy L.; Hillis, David
M. (1999). "Two Living Species of Coelacanths?". Proceedings
of the National Academy of Sciences of the United States of America 96
(22): 12616–20. Bibcode:1999PNAS...9612616H. doi:10.1073/pnas.96.22.12616.
JSTOR 49396. PMC 23015. PMID 10535971.
3.
^ Musick, J.
A. (2000). "Latimeria chalumnae". IUCN Red List of Threatened Species. Version 2013.2. International
Union for Conservation of Nature. Retrieved 2013-12-23.
4.
^ page 200,
Weinberg, Samantha. 2006. A Fish Caught in Time: the Search for the Coelacanth.
HarperCollins Publishers, New York, NY.
7.
^ a b Nelson, Joseph S. (2006). Fishes of the
World. John Wiley & Sons,
Inc. ISBN 0-471-25031-7
9.
^ a b Reuters (2007), "Indonesian fisherman nets ancient fish", Reuters
UK, 2007-05-21, Retrieved on 2007-07-16.
10.
^ Reuters
(2007), "Zanzibar fishermen land ancient fish", Reuters
UK, 2007-07-15, Retrieved on 2009-12-13.
11.
^ page 73,
Weinberg, Samantha. 2006. A Fish Caught in Time: the Search for the Coelacanth.
HarperCollins Publishers, New York, NY.
12.
^ Fricke,
Hans (June 1988). "Coelacanths:The fish that time forgot". National Geographic
173 (6): 824–828.
13.
^ a b Jewett, Susan L., "On the Trail of the Coelacanth, a Living Fossil", The Washington Post,
1998-11-11, Retrieved on 2007-06-19.
14.
^ Erdmann,
Mark V. (April 1999). "An Account of the First Living Coelacanth known to Scientists from
Indonesian Waters". Environmental Biology of Fishes
(Springer Netherlands) 54 (#4): 439–443. doi:10.1023/A:1007584227315.
0378-1909 (Print) 1573-5133 (Online). Retrieved 2007-05-18.
15.
^ Holder,
Mark T., Mark V. Erdmann, Thomas P. Wilcox, Roy L. Caldwell, and David M.
Hillis (1999). "Two living species of coelacanths?". Proceedings
of the National Academy of Sciences of the United States of America 96:
12616–12620. Bibcode:1999PNAS...9612616H. doi:10.1073/pnas.96.22.12616.
PMC 23015. PMID 10535971.
16.
^ Pouyaud,
L., S. Wirjoatmodjo, I. Rachmatika, A. Tjakrawidjaja, R. Hadiaty, and W. Hadie
(1999). "Une nouvelle espèce de coelacanthe: preuves génétiques et
morphologiques". Comptes Rendus de l'Académie des sciences Paris,
Sciences de la vie / Life Sciences 322: 261–267. Bibcode:1999CRASG.322..261P. doi:10.1016/S0764-4469(99)80061-4. PMID 10216801.
17.
^ Inoue J.
G., M. Miya, B. Venkatesh, and M. Nishida (2005). "The mitochondrial
genome of Indonesian coelacanth Latimeria menadoensis (Sarcopterygii:
Coelacanthiformes) and divergence time estimation between the two
coelacanths.". Gene 349: 227–235. doi:10.1016/j.gene.2005.01.008.
PMID 15777665.
19.
^ a b "Dinosaur fish pushed to the brink by deep-sea trawlers",
The Observer, 2006-01-08, Retrieved on 2007-06-18.
20.
^ "Does Tanga need a new
harbour at Mwambani Bay?", Tanzania Natural Resource Forum, 2008-03-05, Retrieved on
2009-02-25.
21.
^ "Population of prehistoric deep-ocean coelacanth may go the way of
the dinosaurs", mongabay.com, 2009-02-25, Retrieved on 2009-02-25.
Taken From http://en.wikipedia.org/wiki/Latimeria
