Friday, August 27, 2010

August 27, 2010 : Basking Shark

Basking Shark

The basking shark (Cetorhinus maximus) is the second largest living shark, after the whale shark. It is a cosmopolitan species, found in all the world's temperate oceans. It is a slow moving and generally harmless filter feeder.

This shark is called the basking shark because it is most often observed when feeding at the surface and appears to be basking in the warmer water there. It is the only member of the family Cetorhinidae. Gunnerus was the first to describe and name the species Cetorhinus maximus from a specimen found in Norway. The genus name Cetorhinus comes from the Greek, ketos which means marine monster or whale and rhinos meaning nose, the species name maximus is from Latin and means "greatest". The following centuries featured more attempts at naming: Squalus isodus, in 1819 by Macri; Squalus elephas, by Lesueur in 1822; Squalus rashleighanus, by Couch in 1838; Squalus cetaceus, by Gronow in 1854; Cetorhinus blainvillei by Capello in 1869; Selachus pennantii, by Cornish in 1885; Cetorhinus maximus infanuncula, by Deinse & Adriani 1953; and finally Cetorhinus maximus normani, by Siccardi 1961.

The largest accurately-measured specimen was trapped in a herring net in the Bay of Fundy, Canada in 1851. Its total length was 12.27 metres (40.3 ft), and it weighed an estimated 19 short tons (17 t). There are dubious reports from Norway of three basking sharks over 12 metres (39 ft), the largest at 13.7 metres (45 ft), dubious because few anywhere near that size have been caught in the area since. Normally the basking shark reaches a length of between 6 metres (20 ft) and a little over 8 metres (26 ft). Some specimens surpass 9–10 metres (30–33 ft), but after years of large-scale fishing, specimens of this size have become rare.

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