Giant squid population 'hammered'

By ANNE BESTON

Those mysterious creatures of the sea, giant squid, are being "hammered" by hoki fishermen, says "squid man" Dr Steve O'Shea, a marine biologist at the National Institute of Water and Atmospheric Research in Wellington.

Dr O'Shea said giant squid were so elusive that there was no knowing how badly their populations were being damaged.

But it was becoming clear that New Zealand's hoki fishery was seriously affecting the squid at crucial times of their lifecycle.

"It's a concern that we've got something the world is really very interested in and it is migrating into the very areas where it is being hit hardest," said Dr O'Shea.

"We are potentially impacting on the breeding cycle of the population to the point where there may come a time when we say 'bang, it's gone'."

The giant squid is more abundant in New Zealand waters than anywhere else on the globe. Between 10 and 23 dead specimens are handed to Niwa by hoki and scampi fishermen each year. But because not all dead specimens are handed in, scientists can only speculate how many more might be killed.

"They are extremely delicate animals," Dr O'Shea said. "Once they're caught in the nets, they're dead."

Not only are adults being killed by the trawlers, but giant squid egg masses are also being destroyed.

The egg masses, 2m or more in diameter, float just below the surface and are also extremely fragile.

Once the eggs hatch, thousands of tiny baby squid are released and swim to the surface. Most are eaten by larval fish and crustaceans, and only a tiny number make it through to maturity.

Giant squid are "top-end predators" - large animals at the top of the food chain - so their populations are unlikely to be numerous.

New Zealand's hoki fisheries are a favourite hunting ground of the giant squid, which breed during June and August along the west coast of the South Island off what is known as the Hokitika Canyon, an important spawning ground for hoki.

An east coast giant squid population breeds from December to early March near the Chatham Rise, a narrow shelf stretching 1000km eastwards from Banks Peninsula and the main nursery ground of hoki.

Giant squid are presumed to live at the bottom of the ocean, but no live one has ever been observed for any length of time - most are seen only after they are dead.

Females grow to more than 12m, males slightly less. The squid are the largest invertebrate known to have existed in the ocean and have the largest eyes of any animal on earth - as big as a human head.

They are a major source of food for whales, particularly sperm whales.

Herald feature: Environment