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.
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.
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 here. It’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.