Posted by: orcaweb | September 24, 2011

Suprise Sighting!

Hi all,

I know that Nathan’s currently writing the blog for last week but I’d quickly like to let you guys know what we saw today. So things might be a bit out of order.

Anyway, it’s the last week that ORCA Whale & Dolphin Officers are onboard the Cap Finistere. I’ve just come back in from an interesting deck watch as we approached Bilbao. Ivo and myself have seen several fin whales, pods of dolphins, flying fish, tuna and sharks. However, the most exciting sighting of the day was a huge leatherback turtle that I saw swimming gracefully alongside the ship.

Leatherback turtles are one of the seven species of sea turtles found globally none is more unique and recognisable. Unlike all other turtles the leatherback has a distinctive torso with an atypical shell. Instead of the typical solid shell leatherback turtles have black scale-less leathery skin forming a single piece shell with pronounced longitudinal ridges which taper into a blunt spike.

They are often believed to be small upturned boats when observed from vessels and the coastline however their head often protrudes above the surface aiding the identification of the animal.

Of all the world’s turtles the leatherback is the largest and may grow up to 2.90m. in length and weigh up to 920kg. The largest ever recorded leatherback turtle washed up dead in west Wales in 1988 and is on now display at the National Museum Cardiff.

The animals have regularly been recorded from the sub-arctic to the tropics. Leatherback turtles are the most frequently recorded species in Britain and Ireland where they are believed to be near the edge of their range. Most British and Irish sightings occur in the warmer summer months when the creatures feed off jellyfish blooms. This prey can be hunted from depths as low as one kilometre. This species is found farther north than any other reptile, marine or terrestrial.

There are believed to be at least two leatherback turtle sub-populations; one in the Atlantic Ocean and another in the Pacific. A has been suggested that a third sub-population may exist in the Indian Ocean. Each sub-population breeds on different nesting beaches. Nesting beaches for the Atlantic sub-population are found on central Africa, Caribbean islands and northern South America whereas Pacific Ocean leatherback turtles nest on western South America, Mexico and Costa Rica. It is believed that Indian Ocean leatherback turtles nest in Malaysia. Nesting occurs from February to August, depending on the location, and the eggs usually hatch after 20 to 25 days. Each nest contains about 110 eggs. Leatherback turtles are known to travel vast distances from nesting areas onshore to foraging areas which are often in the open ocean.

According to International Union for the Conservation of Nature (IUCN) the leatherback turtle is critically endangered. Many dead leatherback turtles have plastic bags blocking their gut leading the animal to starve. It is believed that these plastic bags are mistaken for jellyfish. The creatures are also vulnerable to getting caught in fishing gear preventing the animals from surfacing to breath.

Four other species of turtles have been spotted around the UK and Ireland. These are the green, hawksbill, loggerhead and Kemp’s Ridley turtles. Keep your eyes open!

Keep checking this website for our final blogs of the season!

Mike

ORCA Whale & Dolphin Officer

Cap Finistere

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