Here's what you need to know about sustainable seafood

The majority of our ecological footprint is caused by the food we eat. Many people, myself included, choose to reduce or even eliminate meat consumption in order to reduce this impact, and certainly it does. Often, however, people then turn to seafood as a substitute, so it’s important that we consider the implications of this choice.Let’s start with a few facts so we’re on the same page:1)   the number of fish in the ocean is finite. They can, in theory, be counted.2)   all species are an important part of the ocean’s ecosystems, be they generalists or occupiers of specific ecological niches.3)   everything is connected to the oceans. Everything you eat, drink, every breath you take is determined by the health of the oceans via a complex global ecosystem.With that in mind, according to a 2011 report by the International Programme on the State of the Oceans we are "at high risk for entering a phase of extinction of marine species unprecedented in human history" and indeed probably thousands of marine species have already become extinct in the last century alone. Yet the ocean remains one of the least understood and most disregarded aspects of life on Earth, possibly because from our usual terrestrial viewpoint a healthy ocean looks the same as a dead one.Beneath the surface, however, the ugly combination of the effects of overfishing, marine pollution and climate change are very apparent.

What's the problem?

Enormous damage is caused by destructive fishing practices which destroy marine habitat, such as dragging nets the size of football fields across the sea bed, or by targeting and obliterating fish populations without understanding their breeding cycle, thereby dramatically reducing their ability to return to normal numbers. These practices are causing once abundant iconic marine species to disappear from the oceans. The loss of a species can, in turn, shift the fine balance of an ecosystem through complicated feedback mechanisms. For example, predators such as sharks significantly affect the food web by preying on other fish, thereby keeping in check the negative impacts they have on natural systems if allowed to reproduce unabated.As if this isn’t damaging enough, climate change and pollution are fundamentally changing the chemistry of the oceans. The ocean has absorbed approximately 30% of the carbon dioxide and 80% of the additional heat we have generated in the past 200 years, and nutrient runoff from industry and chemical intensive agriculture aren’t helping either. Vast areas of coral have become bleached, sea water has acidified, and algal blooms and deoxygenated water events have increased as a result of our behavior on land since industrialization.

What about aquaculture?

Aquaculture does not solve this problem because most farmed fish, such as salmon, are fed fishmeal sourced in an unsustainable way. Also, farmed fish live in stressful environments causing them to be prone to disease which they can share with wild populations, and a lot of farmed seafood imported from Asia is also responsible for unparalleled levels of marine pollution.If we want to keep eating seafood and to maintain the livelihoods of billions of marine-dependent people around the world we need to ease up on marine ecosystems. This problem can be solved in a short space of time if we act decisively.

What can we do about it?

The simplest and best thing we can do is to get informed about the problem and to be mindful of our seafood consumption. There are some useful tools out there to help with this. I recommend the Australian Sustainable Seafood Guide available online, in hardcopy or as a free iPhone app from the Australian Marine Conservation Society. It offers comprehensive advice and information on a huge range of species, suggests better alternatives and also offers some useful rules of thumb to keep in mind. In short, it’s got all the info you need to put the tough questions to waiters, chefs and seafood markets so you can make a sustainable choice and start an essential change.

Ending Overfishing from OCEAN2012 on Vimeo.Image credit: Richard LingWords by Michael Burnside