Swaying slightly in my chair in the campaign office behind the bridge, catching up on emails, I find an article on the work of Dr Steve O'Shea. Steve is a prominent squid biologist from New Zealand, and Director of the Earth and Oceanic Sciences Research Institute at the Auckland University of Technology. He has been investigating the underlying causes of what he considers to be an exceptional number of recent whale strandings. Some of these animals showed definite signs of being malnourished. Steve believes that commercial over-exploitation of deep sea fish and squid stocks may be impacting on the sperm whales and other smaller deep-diving whales that feed on them.

Studies conducted 40 years ago show that deep water fish species such as orange roughy, hoki, ling, rig, and southern kingfish made up 37 % of the diet of sperm whales in New Zealand. These species are the same as those targeted by deep sea bottom trawlers. Later studies conducted in the 1990s showed that the New Zealand sperm whales' diet had changed and that the animals were eating 100% squid diet. But even this food souce now appears to be threatened.

According to Steve O'Shea, five species of squid and octopus found in New Zealand seas are classified as critically endangered. In addition, 78 of the 85 species of squid in New Zealand waters release egg masses to breed - these fragile, gelatinous eggs are being cut to ribbons by trawlers' nets. Learn more about giant squid behaviour here.

This does not bode well for New Zealand's sperm whales. The fact is that, despite the best efforts of dedicated marine biologists like Steve, we know so little of the ecology of these squid species or their importance in the wider ecosystem - which of course just underscores the urgent need for a moratorium on deep sea bottom trawling.

- Richard