Giant sepia
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Giant sepia ( Sepia apama ) |
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| Gray , 1849 |
The giant sepia ( Sepia apama ) is the world's largest species of sepia from the group of cephalopods (Cephalopoda).
features
The animals have a coat up to 50 cm long and can weigh over 10.5 kg. The coat is broadly oval with a fin hem that even protrudes over the edge of the coat at the front end. The fin hem is interrupted at the rear end. The sepia shell is much narrower than the broad habit of the coat would suggest. The terminal spine is still well developed in juvenile animals, but largely disappears in adult animals. The funnel is very broad at the base and relatively long; it extends to the level of the eye. The head is short and broad, but slightly narrower than the coat. The arms of males and females are short and about the same length. Four longitudinal rows of suction cups are developed on the arm. The male's left ventral arm is developed as a hectocotylus . The tentacles are stretched out about 4 to 5 times as long as the ordinary arms. The clubs at the front end of the tentacles are crescent-shaped and have numerous, very differently sized suction cups. The top of the coat is red-brown in color, but can be greatly changed, especially when paired.
Way of life, occurrence and distribution
The giant spies are native to all of South Australia as well as to West and East Australia south of the 23rd parallel. They usually stay between stony reefs , seaweeds or over sandy and muddy seabeds at a depth of up to 100 meters. They eat fish, crabs and other crustaceans. Reproduction takes place during the months of April to September, which corresponds to the Australian winter. The male changes its normal color and tries to impress the female with rapidly changing colors and patterns. The males guard the females and ward off rivals. This leads to strange behavior from small males. They take on the colors of the females to deceive the dominant males. These even begin to protect the supposed females. Now the smaller males have access to the females and the opportunity to reproduce. The mating is head to head. The male transfers the spermatophore capsules with the help of the hectocotylus into a special pocket (spermathek) of the female. The peak of egg laying in the Spencer Gulf is in May and June. The animals die shortly after mating and after laying the eggs. The eggs are lemon-shaped and are laid in crevices in shallow water. The development time is three to five months at low water temperatures of only about 12 °. These low temperatures, which must prevail during the egg-laying and development of the egg, also seem to prevent the species from spreading to more northerly, and thus warmer, waters of Australia.
Commercial importance
The giant sepia is mainly caught as bycatch in the shrimp fishery and by fishing trawlers. It is also often speared by divers or caught with hook lines. It can therefore be found regularly at regional fish markets on the south coast of Australia. However, it is difficult to get information on quantities.
Individual evidence
- ↑ Jereb & Roper p. 68
literature
- Patrizia Jereb and Clyde FE Roper: Cephalopods of the World - An Annotated and Illustrated Catalog of Cephalopod Species Known to Date. Volume 1 Chambered Nautiluses and Sepioids (Nautilidae, Sepiidae, Sepiolidae, Sepiadariidae, Isiosepiidae and Spirulidae). FAO Species Catalog for Fishery Purposes, No. 4, 1: 1-262, Rome 2005 ISBN 92-5-105383-9
- Mark Norman: Cephalopods: A World Guide , ConchBooks, Hackenheim 2000
- Harry Erhardt and Horst Moosleitner: Marine Atlas: V. 3 , Steven Simpson Books, 1998, ISBN 3-88244-055-4 , p. 796
Web links
- Information with pictures
- Sepia apama inthe IUCN 2013 Red List of Threatened Species . Posted by: Barratt, I. & Allcock, L., 2009. Retrieved February 13, 2014.