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A seafood diet reduces your carbon footprint, but not all seafood are equal

Updated: Jun 14, 2022

Marine fisheries currently play a role in food security and nutrition for more that 700 million people around the world, and a restored ocean could feed 1 billion people a seafood meal every day.

Feeding the world doesn't have to take such a heavy toll on the environment. When incorporated into a balance diet, wild seafood alleviates the demand for red meat and supplies a healthy source of protein and micronutrients.

There's no free lunch. The question is, what can the planet afford?

Of course, to reduce carbon footprints as much as possible, the best bet is to eat veggies. But among animal products, wild sustainable seafood is your best option.

Most people in the U.S. and other developed counties are high meat-eaters, consuming 1.5lbs per week. One high meat-eater replacing that meat with fish would save the emissions equivalent of about 6,000 miles driven over the course of a year.

Land based meat, specifically meat from ruminants, plays a hugely disproportionate role in deforestation since most of the world's soy is produced as feed for livestock. Demand for beef and other red meat is, by far, the largest driver of deforestation around the world.

In addition to being one of the healthiest and most carbon-efficient foods on the planet, wild-caught fish require no land, no freshwater, and involves far less animal cruelty compared to farmed animals.

Farmed seafood has similar impacts as land-based food, but is highly dependent on the kind of seafood being cultivated. Farmed bivalves, like oysters, mussels, and clams are extremely good for the environment. They are typically grown right offshore (requiring little to no boat fuel), require no freshwater, can be grown vertically using very little ocean space, and actually take carbon out of the environment as they grow.

Is aquaculture a solution to overfishing?

A recent study put it to the test and the answer, so far, is no. If the theory is true, then modeling should show that increased aquaculture production is correlated with decreases in wild catch. Instead, Longo et al. (2018) found that aquaculture has been supplementing - not suppressing wild fishery captures.

Aquaculture is the practice of farming fish under controlled conditions and includes both salt and freshwater species. It's the world's fastest-growing food production sector, generating around 44 per cent of the fish we consume; and yet, in order to sustain its growth, it's heavily reliant on the capture of wild-caught fish.

Over 69 per cent of wild-caught fishmeal and 75 per cent of wild-caught fish oil produced is fed directly to famed fish. We are literally catching fish, to feed fish!

Photo by WikiMedia user OgreBot

The most commonly farmed species is the Atlantic salmon, with around one million salmon meals eaten every day in Britain. But as every pound of farmed salmon consumes around three pounds of wild-caught fish, there are far more lives lost.

Fish used for animal feed

One-third of the world's ocean fish catch is ground up for animal feed, a potential problem for marine ecosystems and waste of a resource that could directly nourish humans.

The fish being used to feed pigs, chickens and farmed-raised fish are often thought of as bait, including anchovies, sardines, menhaden and other small - to medium sized species.

These so-called forage fish account for 37 per cent, or 31.5 million tons, of all fish taken from the world's oceans each year. Ninety percent of that catch is turned into fish meal or fish oil, most of which is used as agricultural and aqua cultural feed.

School of sardines at Panagsama beach, Moalboal, Philippines / Photo credit to Henry Jager

Fish are key to the survival of our planet as they play an important role in the nutrient cycles of marine ecosystems. Forage fish are near the base of the marine food web, nourishing larger fish, ocean-dwelling marine mammals and sea birds. Excessive removal of these small fish from the ocean environment could hurt the species that feed on them.

Aside from the potential ecological consequences, the taking of these large number of forage fish interferes with food security for humans. On average, it takes three to five pounds (1.36 to 2.27 kg) of fishmeal to produce one pound (0.45 kg) of farm-raised fish. If you are creating protein for humans to consume, does it make sense to take three to five pounds of perfectly good food and convert it into only one pound of food?

Most forage fish are high in omega 3 fatty acids, protein, vitamin D, calcium and other nutrients, it makes sense for humans to consume these fish directly rather than to feed them to livestock and farmed fish.

While fish-farming is presented as a solution to drive down overfishing, the reality is that it exacerbates the problem by its reliance on wild-caught fish and is therefore incapable of meeting current and projected demands for seafood.

Sustainable fishing helps to recover fish stocks

If you are an environmentally concerned person like me, you are probably wondering about the state of our oceans and their fish stocks. I have often wondered if global fish stocks are actually recovering or declining.

New research concludes that roughly 50% of the world’s oceans’ fish stocks are recovering, or already have recovered, and are now at proposed target rates. And it is all thanks to highly effective fisheries management methods.

The research report, published by the PNAS (Proceedings of the National Academy of Sciences of the United States of America), shows that efforts of sustainable fishing can yield awesome results and explains, in detail, just how powerful this fishing method can be.

If maximum catch quotas are kept, fish stocks seem to be able to recover fairly quickly and their numbers can virtually explode after only a couple of years. If you let them, fish will recover and be plentiful.

In the recent past, there have been many reports on ever-increasing levels of overfishing and decreasing fish stocks all over the world. At the same time, many large-scale fisheries management efforts have been put into place, in order to counteract this development. What’s especially positive is the fact that this shows how well scientists and fishermen can work together in order to bring about a sustainable fishing industry.

If there is a political and economic will, modern fisheries management efforts could restore many more fisheries and fish stocks.

Of course, it will take time, and many other factors (such as climate change) play an important role as well. But if we do not start to act and change things now, it might soon be too late to turn the tide!

Photo credit to Paul Hilton

Be a responsible consumer

There are ways to eat fish sustainably, ensuring that populations remain for the future. Choosing environmentally friendly seafood can be tricky as location plays a big role. It is therefor important to do your own research based on where you live, so you can make informed decisions about the fish you buy and enjoy seafood guilt free.

How to make sustainable, healthy fish choices:

  • Choose local or domestic seafood

  • Choose wild-caught (except oysters and clams)

  • If it's farmed, it must be from recirculating systems and their diet must consist of at least 50% alternative protein sources such as soybean meal.

  • Choose fish caught by hand line, hook and line (rod and reel), trolling (one or more fishing lines are drawn through the water behind a moving boat), or spearfishing. Trolling is often confused with trawling (a net is drawn through the water - bottom trawlers has devastating environmental impacts).

  • Avoid fish high in mercury, the bigger the fish, the more mercury it has.

Here's a list of fish you should keep off your plate, no matter where you live:

  • Lobster / Scampi (Langoustine)

  • Shrimp (Prawns)

  • Octopus

  • Caviar

  • Atlantic cod

  • Tuna (Pole and line caught Skipjack Tuna is sustainable)

  • Orange Roughy

  • King Crab

  • Atlantic Salmon (Wild caught Alaskan Sockeye Salmon is sustainable)

  • Eel

  • Atlantic Halibut

  • Sea Bass

  • Sole

  • Mackerel

  • Shark, Skate and Rays

  • Swordfish

  • Tilefish

Australian Institute of Marine Science | Credit: LTMP

The ocean is important to all of us as a source of food. Fishing is the world’s greatest wild harvest. Estimates suggest that No Fish Zones over a third of our costal seas would be sufficient to provide us with all the fish we will ever need, and allow our oceans to recover and thrive once more.

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