SCICOMM
A Science Voice from New Zealand

SeaWeek: Eating Small

 by Bill Morris

Photo: Stockxchng

This week is Seaweek, a chance to learn and be inspired by the beautiful ocean that surrounds our country. We should all be well aware by now that the oceans of the world are in serious peril, plundered by overfishing, littered with pollution and susceptible to dramatic change as a result of climate change. Those who have worked in and around the ocean for years in New Zealand can tell you the changes have been rapid and dramatic.

Lloyd Davis, the director of the Centre for Science Communication recently wrote this article for the Otago Daily Times in which he describes how Pacific Island fishermen, by targeting the bigger species such as parrotfish, grouper and snapper are draining their reef systems’ resources. It takes several kilos of small fish to allow a big fish to grow. Lloyd’s article discusses the work of scientist Michel Blanc, who believes islanders should be consuming the smaller sardines and anchovies, which are just as nutritious and appealing to eat.

I once visited a tuna farm in Australia where I witnessed hundreds of tonnes of sardines being shoveled down the throats of “farmed” bluefin tuna. While some of the sardines were caught locally, many more were caught off the coast of America and shipped across the ocean to feed these tuna. The tuna, caught wild in the Great Australian Bight, were being fattened in pens for sale to foreign markets as whole fish. In the markets of Tokyo each tuna would collect many thousands of dollars.

Putting aside the dubious sustainability of this fishing method, the waste of the feeding system was obvious. It takes over seven kilos of sardines for a bluefin tuna to gain an extra kilogram of weight. A large tuna requires its own bodyweight of smaller fish each ten days just to survive. The tuna were being doubled in size during their time in captivity to a weight of around 25 kilos, so each tuna that ended up on the market floor in Tokyo had been fed hundreds of kilos of sardines.

Anyone who’s fried up a fresh sardine in butter knows they are one of the most delicious fish to eat- in my opinion better than tuna. Demand for the flesh of the big tuna species is driving these spectacular animals towards extinction. In the process companies that fatten tuna are vacuuming up the protein resources of the sea in order to convert them to expensive tuna flesh that most people in the world would never dream of being able to afford.

If we are to have any hope of feeding the hungry world this century, we need to put an end to such incredibly inefficient and inequitable processes. The big fish of the ocean like tuna, marlin and groupers have been heavily overfished, often to the point of extinction. A well-published study has found that up to 90% of the big fish species in the world are already gone. The wealthy nations of the world are devouring these big fish at the expense of the ocean and ultimately, the percentage of the world’s population who will starve to death when global fisheries collapse.

A 2010  National Geographic study coined the term “Seafoodprint,” to display how individual nations consume the world’s fish resources. China, Japan and the United States were the top consumers -the United States made the top three not because its per-capita fish consumption is high, but because the fish Americans tend to eat are big ones, including tuna and Chilean Sea Bass (actually Patagonian or Antarctic toothfish), which have already consumed massive amounts of smaller fish to attain their size.

At least a partial answer to the looming seafood crisis could be  to find ways to encourage people eat smaller fish like sardines instead of top predatory fish like tuna. Not only are they far more common, but eating smaller fish is healthier as they don’t have anywhere near the levels of mercury and other toxins associated with apex predators like tuna. Currently most of the sardines caught in the world are fed to larger fish in fish farms or to caged pigs and chickens.

To mark SeaWeek, The Centre is staging a film screening of some of our sea-related films at the Otago Museum on Friday 9th March. Come down and show your support.

 

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