Does The Elephant Fish Ever Forget?

Press, Volume CVII, Issue 31378, 25 May 1967, Page 9

Does The Elephant Fish Ever Forget?

Very little is known about the “peculiarlysnouted” and “whiptailed” elephant fish which inhabit the waters off Canterbury and are the staple diet of fish and chip shop customers.

At what age does the female elephant fish breed? How old do the seawater elephants live? Do they go to different schools, or do they all belong to the same one? Does an elephant fish forget, and move away from Canterbury never to return to its home waters? What does an elephant fish eat? Why have elephant fish become scarcer off Lyttelton and Timaru in recent years? Should they be conserved?

These are some of the questions Mr A. Coakley, of the Marine Department laboratory in Ricarton, is hoping to find out by tagging elephant fish three successive days each month from August to July next year. A fishing trawler

wil operate from Lyttelton and one from Timaru. A small number of elephant fish were tagged by Mr Coakley and assistants last year. A number of different kinds of tags were used in an experiment to find out which was the best tag to use. But the experiment was highly unsatisfactory, Mr Coakley said because not enough of the tagged fish had been caught. The elephant fish is an unprepossessing creature and telling its age once it has matured is difficult because it has no scales. The fish come up to the breeding stage in about four years—which indicates a relatively long life span. Some of the elephant fish, all ages and sizes, will be taken back to the laboratory by Mr Coakley. They will be examined to determine their eating habits (which could give a clue to their habitat) and for a lot more information which will enable the marine biologists to fill the gaps in this fish tale. Terakihi, gurnet and, occasionally flounders and other

flat fish, are caught more frequently than elephant fish in Canterbury waters, but elephant fish fillets have been exported to Australia to add to the commercial importance of the species. The fish is most interesting in that it does not have a true backbone. Research has shown that it has a bead with a mingling of primitive and advanced anatomical features which give rise to far-reaehing questions on its relationship not only to other fishes but to animals, such as frogs and other lung-breathing forms. It has been maintained that the development of the head, when finally worked out, will be of the utmost importance. It will throw much light on the line of early evolution at a time when the ihost primitive fishes were beginning to acquire those characteristics, the possession of which first impelled their changing descendants along the roads of evolution tp the higher vertebrates.

The trunk of cartilaginous or gristly prominence from the snout, is a most interesting feature. It seems that the trunk is used to locate and assist in securing' shell fish out of their habitat below the level of the sea floor. Stomach examination of elephant fish has shown it to live on 15 species of hard-shelled molluscs.

The trunk may also be used as a sensory organ to.receive impressions of life below the sea floor—the trunk thus finding, digging out and trans-

ferring the sbell-fish to the mouth of the elephant fish. The mouth contains powerful teeth which grinfl the shellfish into very small bits—as shown by stomach contents. Jelly fish remains have also been found in the stomachs of elephant fish—and it is unusual that a fish feeds not only on shellfish but also on very soft fish. From a commercial point of view, the elephant fish gives high proportion of

i edible food and little waste. In this respect it is better • value than cod. In calories ! value the elephant fish is ■ well below tarakihi but is ■ higher than sand flounder and ! many other popular food fish., i Commercial fishermen re- ■ turning tagged elephant fish i get a reward from the Marine : Department. Success in the survey ,of elephant fish could : bring rewards not only to i fishermen but. to all New Zea- ’ landers.