Report: Sustainable practices needed to conserve fisheries

Global fish production has reached an all-time high, according to research done by Nourishing the Planet for the Worldwatch Institute's Vital Signs Online publication.

Aquaculture, or fish farming - once a minor contributor to total fish harvest - increased 50-fold between the 1950s and 2008 and now contributes nearly half of all fish produced worldwide.

According to the UN FAO, an estimated 53% of fisheries are considered fully exploited - harvested to their maximum sustainable levels - with no room for expansion in production.

Population growth and a higher demand for dietary protein are putting increasing pressure on depleted stocks and threatened ecosystems.

Mainstream approaches to fisheries management have focused narrowly on short-term profit and boosting production.

Worldwatch's analysis states that practices will need to shift to more sustainable strategies to meet demand and support fishing communities.

Increased farming of large predators, such as salmon and tuna, has led to overfishing of prey fish, including anchoveta and herring, which are commonly used as fishmeal.

It generally takes at least 3kg of feed to produce one kilogram of salmon.

The shrinking of the numbers of prey species threatens the entire food chain, putting further stress on large predator stocks.

"Even as we depend more on farmed fish, a growing scarcity of fish-feed may jeopardize future expansion of the industry," said Brian Halweil, Worldwatch senior researcher and co-project director of the Institute's Nourishing the Planet project, a two-year evaluation of agricultural innovations.

This could also negatively affect the economies of developing countries, home to the nearly 60% of the world's fishers that are classified as small-scale commercial or subsistence fishers.