Aquaculture – the fancy word for fish farming


We’re running out of wild fish stocks, so it seems a good idea to investigate our other options, and one of those is farming fish. Farmed fish provided us with 58% of the fish we ate in 2014, and it can help try to take pressure off the wild stocks, giving them a chance to recover while still allowing us to meet our increasing need for protein worldwide. Many of the same species we capture at sea can also be farmed in more controlled conditions, but raising farmed fish sustainably can be a bit of an art.


Fish farm pens at sea. Source

Whilst farming fish can seem like a great solution for dwindling stocks, it’s important to think about the wider impacts. If we’re going to farm fish on a large scale, we’ll need to provide and manage everything that the ocean would ourselves, starting with food.

So what do farmed fish eat? Ironically, wild fish, amongst other things. Around a third of the fish which are caught worldwide are used for fishmeal, there are often the smaller species at the bottom of the food chain which bounce back quicker if exploited sustainably. If we’re trying to farm a carnivorous species that would eat other fish in the wild, then they’re going to need fish in their farmed diet too.

The problem comes when we farm some carnivorous species which are higher up the food chain, like salmon, where in order to feed them sometimes more wild fish are extracted, by weight, than are produced as farmed fish. This is fairly pointless as all it is doing is converting smaller and less valuable fish species into higher value species, without an actual net increase in protein. An effective fish farm uses fishmeal from responsibly sourced wild fish, and will make sure that there is an overall increase in protein gained.


Farmed salmon. Source

So can we raise veggie fish? Yes, not all fish actually need wild fish protein in their diets, and research is also being done to try to find a way to recreate the omega-3 fatty acids and other essential nutrients which the farmed fish get from the wild fish content in their feeds. Fish processing is also quite a wasteful business, and using the trimmings from fish processing factories in fishmeal could reduce how many wild fish we have to catch for feed. Finding an alternative will help keep the price down too, as the cost of fishmeal and oil will only increase as we start to run out. We can also switch the species that we raise to those which are less reliant on fish, like carp, or to species which are veggie themselves, like tilapia.

Escapees can be a problem when it comes to farming fish, because they are raised in pens or cages in the sea so the risk of some escaping and breeding with wild fish is always there. If they do crossbreed they can reduce the ability of wild fish to survive at sea.

People have all sorts of views on genetic modification, but the main idea with GM fish is that they can grow a lot faster than wild stocks and are much more efficient at processing food so they don’t need as much food as wild fish or standard farmed fish. They can also be engineered to be sterile so that crossbreeding isn’t as much of an issue. However there are still concerns about their impact on wild fish populations, and also on human health. The US has just approved the production and sale of GM salmon for food, but it’s too early to know how popular it will be.

Growing lots of fish in an enclosed space means that disease can quickly become a problem, so often lots of pesticides and antibiotics have to be pumped into the water to help keep these diseases in check. Huge amounts of nutrients and chemicals can build up in a small space in the ocean, which can upset nutrient cycles, or in more enclosed spaces like mangroves the chemicals can form a kind of toxic soup.


Shrimp farm in the mangroves. Source

We’re becoming reliant on aquaculture already, and if we’re going to depend on it even more we need to clean up the process a bit. Ideally we need to  develop more synthetic feeds so we don’t have to catch as many wild fish to feed the farmed ones, and find a more natural way of managing the impacts of farming a lot of fish in an enclosed area. It’s often hard to tell exactly where your fish comes from and how it was caught or raised, so look for the Aquaculture Stewardship Council label on packacking and that’s a good sign that what you’re about to buy has been farmed responsibly.


Aquaculture Stewardship Council label. Source

The weird, the wonderful and the downright ugly


Wolffish, Goblin shark, Viperfish, Vampire squid. These fierce sounding species hang out in the depths of the ocean, doing whatever they do down there, which we actually don’t know a lot about. Much of the deep sea hasn’t been explored by humans, and if you look at this animation you’ll see why. Check out this link before reading the rest to put the depth of the ocean into perspective.

Giant Squid (l) Deep sea Anglerfish (c) Pacific Wolffish (r)

Giant Squid (l) Deep sea Anglerfish (c) Pacific Viperfish (r)

The deepest point is nearly 11,000m deep, but sunlight only reaches as far as 1000m. The pressure quickly becomes too much for us. Divers breathing regular air can only get to 50m deep, some can complete a more technical dive using lots of gear to 100m, and after that it’s submarine territory.  These can either be human-operated (HOVs) or remote-operated (ROVs). Explorer-filmmaker James Cameron reached the bottom of the deepest point of the ocean in a one man sub in 2012, an incredible feat.

Deep sea species look odd, there’s no denying it, and as you learn more about them you can see why. They are adapted to live under huge pressures, without light and with little food. Some of what they do eat is called ‘marine snow’, dead flakes of organic matter which float down from the sunlit waters. This darkness means some species make their own light, known as bioluminescence, and some have developed lures to attract prey. Many have huge mouths and hinged jaws to make the most of the few feeding opportunities they get. Some species can’t see at all because they don’t need to, and most are extremely slow growing individuals which reach maturity late. The fact that they grow so slowly and only reproduce late in their lives means that they are hugely vulnerable to the impact of fishing as their populations will not bounce back quickly. The deepest fish have been found at 8370 metres but no fish have been found deeper than 8,400m, only other creatures like worms and anemones, and scientists aren’t quite sure why.


Goblin Sharks don’t win beauty contests. Source:

Even though we can rarely reach these depths ourselves it doesn’t mean we’re not having an impact there. A deep sea survey in 2013 found a bin bag at 5000m deep, in an area which was protected at the surface. Deep sea fishing removes huge quantities of slow growing species, whose populations do not recover well from overfishing, and mining can cause pollution on a vast scale. Both can cause extensive and irreparable damage to the seabed.

It comes down to charismatic megafauna again. Just because they’re really ugly, and also far out of sight, doesn’t mean that we shouldn’t care or consider our impact on deep sea creatures and their environment. The fact that plastic is reaching these depths is a sign that things have gone too far, and we need to act quickly to reduce our plastic waste before we completely saturate the ocean with debris. We also need to choose our fish carefully –  don’t eat deep water species, slow growing species or already overfished stocks – you can find out which ones are good to eat hereIt’s the ‘little bits of good all put together’ that will help sort these problems out.  If enough people do their bit then it all adds up and these bizarre deep sea creatures will be able to continue to cruise the depths, doing whatever they do, well into the future.

Our ocean giants


Our ocean giants are the species at the top of the food chain, also known as the apex predators, which roam the oceans with little to fear except us.

Sharks, whales and dolphins are all crucial to the health of the oceans but they are under threat from intensive fishing and marine pollution. These huge creatures live for a long time and grow slowly, but they don’t have many offspring in their lifetimes so their populations do not bounce back well from overfishing.

Sharks are killed in their millions for their fins, they get caught in fishing nets along with dolphins, and whales are still hunted in some places. They are all also affected by marine pollution, impacted by plastic in the oceans and changing water quality from oil spills and noise from shipping.

Hong Kong Shark Fin_Leff

Shark fins Source:

Marine food webs are carefully balanced and so removing the top predators has a knock-on effect on the rest of the ecosystem. These top predators are called ‘keystone’ species and they’re really important for keeping the ocean healthy. Apex predators keep the populations of their prey species in check, without them disease in fish populations is more common and one species can overtake an area more easily, so apex predators keep the diversity of marine species higher.


Marine trophic pyramid Source:

Part of the problem is that there is a lot that we don’t know about how the ocean responds to pressure from humans, and this means that it’s quite likely that it will respond in a way we can’t predict if we push it too far.

The difficulty with protecting ocean giants is that they are migratory and roam huge distances. Some also dive very deep so it’s hard to know where they are and this means designating vast Marine Protected Areas is not the most effective way of protecting them. One thing we can do though is to work out where these giants go to breed and feed, and protect these areas. These are often nutrient rich areas where currents rise up to the surface from the depths, or different currents swirl together mixing the nutrients they are carrying making it an area which is rich in fish and therefore the perfect meeting place for keystone species.

In the UK the Wildlife Trusts have identified 17 ‘megafauna hotspots’ where this occurs and proposed them as ideal new MPA sites to help protect UK ocean giants. You can find the different sites here.

So removing these ocean giants is unbalancing the ocean ecosystem like a wobbling Jenga tower. Protecting them by enforcing strict catch limits based on the best available evidence on the population size, limiting whaling for scientific purposes,  reducing consumer demand for shark fin soup and minimising the amount of plastic entering the ocean will help restabilise the ocean ecosystem through the recovery of our ocean giants.

Who doesn’t want to tweet a shark?

Fisheries, Step Up For The Sea, Uncategorized

I’ve recently discovered the great white shark research being done by the scientists at OCEARCH, and keeping up with the great whites of the world has become a bit addictive.

Global data on mature great whites is lacking and this project is helping to fill the knowledge gap. Sharks are tagged, measured and assessed on a specially adapted research vessel, then released to do their thing in the ocean. Every time they surface for lScreen Shot 2015-09-14 at 20.06.41ong enough their tracker will ping and update their location.

This is important research because learning more about these vulnerable individuals gives us a lot more to work with in terms of deciding the most appropriate conservation strategies. The Shark Tracker can also be integrated into the curriculum to get kids learning more about sharks, whilst live-tracking some real ones at the same time.

Turns out, Mary Lee, Carl, Katharine and others are keen on social media and are frequently active on Twitter.

You can also get the Shark Tracker for
your phone, which is definitely going to make the next queue I’m in more interesting.


Switch the fish – how you can help


Do your little bit of good where you are; it is those little bits of good put all together that overwhelm the world – Desmond Tutu

I’m veggie because I don’t want to eat fish. Not eating meat just followed on from that. I consider it my little bit of good for the environment. I don’t want to eat fish because there aren’t that many left and if we don’t give them a chance the situation won’t improve. That’s a decision I took on the basis of a lot of reading, some fantastic work experience which opened my eyes to a lot of problems that the ocean is facing and the realisation that the measures we’re putting in place are not always working well.

I find myself justifying being veggie quite a lot. Sometimes people are interested because it’s a bit different, and sometimes it’s disbelief and quiet concern at the fact that I turn down bacon sandwiches.

People say ‘why don’t you eat it, it’s dead anyway’. I say, if enough people don’t eat it then demand will fall over time and the stock will be under less pressure. This is clearly a very simplistic justification, but I find it works and prevents fish politics at dinner.

People say ‘why are you veggie, you’re not going to make a difference on your own’. I say, that’s not the point. It’s extremely difficult to make a difference on your own. The point is I’m happy to be contributing to a larger group of people who feel the same way, and turn down fish for the same sustainability reasons. It’s this group which can make a difference, more so than just me.

That’s not to say everyone should stop eating fish immediately. You don’t have to be veggie to help make a difference. We are reliant on fish as a significant source of protein and therefore everyone cutting it out is unrealistic and unreasonable. What people can do is make more sustainable choices when buying fish to help take some pressure off the most threatened species.

There are lots of easy swaps to make and an app so you don’t have to remember them. You can also ask at the counter about sustainable choices, or look for the Marine Stewardship Council tick logo on packaging. msctick

So if everyone makes more sustainable choices when they buy fish, these ‘little bits of good put all together’ will help to preserve fish stocks for the future. Don’t worry if it feels like you’re not making a difference on your own – think of the bigger picture.

Find the Good Fish Guide here

Get the app

Sustainable Fish Cities fish swaps

Sainsbury’s ‘Switch the Fish’ campaign

Global Fishing Watch


90% of global fisheries are thought to be fully exploited or over-fished (UNFAO, 2014). Global Fishing Watch is a collaboration between SkyTruth, Oceana and Google, who have created this interactive tool where all trackable fishing vessels can be located on a map.

It is currently in the prototype stage and it will be available to the public so that anyone can be aware of, and help monitor, commercial fishing across the globe.

Video explaining the project and plenty more information

Which fish?


Choosing sustainable seafood and making ethical choices can make shopping a daunting task. How are you meant to know which to choose? Several handy guides have been produced to help you quickly identify the more sustainable options. These are just a few:

National Geographic

The National Geographic has produced an interactive ‘Seafood Decision Guide’ which tells you about the species, and where it ranks in terms of sustainability, Omega-3 content and mercury level.

You can find it here: Seafood Decision Guide

Marine Conservation Society

The Marine Conservation Society ‘Good Fish Guide’ is an easy to read, colour-coded guide which also comes as an app – perfect for quick reference whilst shopping.

Here it is: MCS Pocket Guide

Also check out the Good Fish Guide App on the App Store!

World Wildlife Fund

As this is clearly a global issue, WWF have produced guides for different countries, in different languages.

Links on WWF’s website here: WWF Consumer Guides

Have a browse and check out how sustainable your favourite seafood is – and whether there is a more sustainable option to try!