When fishermen catch fish, there are inevitably fewer fish left in the sea. If it weren’t for fishes’ ability to reproduce relatively quickly, fishermen would simply ‘mine down’ the resource and there would be nothing left. But fishing has been sustained for many millennia because fish can reproduce and recover their numbers. This source of potentially endless protein is what makes our fish stocks one of our most valuable renewable resources.

But the rate at which fishes reproduce varies, and thus so does the rate at which they can be fished sustainably. Some – like sharks and rays – reproduce more slowly than others, making them more vulnerable to fishing pressure. If we kill sharks more quickly than they reproduce, we are overfishing; their numbers will dwindle and we won’t be able to catch many sharks in the future. Overfishing is a problem for both sharks and us.

Sharks and rays are generally subjected to ubiquitous and relentless fishing pressure – a pressure so great that it’s the leading threat to these animals. Sharks are caught in directed fisheries, where fishermen aim to catch them for their meat, fins, liver oil, skin (for leather), cartilage (for medicine) and teeth and jaws (for curios). They are also taken as incidental by-catch, when fishermen target other species like tuna and swordfish, but accidentally end up with a shark in their net or on their line. Because sharks are a valuable catch, fishermen often keep them. Yet even if they return a shark to the sea, it is often so traumatised that it dies shortly afterwards. Finning – the practice of removing a shark’s fins and throwing the rest of the fish back into the ocean – contributes to the problem of overfishing and is now illegal in most countries. It’s a cruel and wasteful practice that is driven by the demand for shark-fin soup.

Scientists estimate that each year 100 million sharks are removed from our oceans, and much of this haul is illegal, unreported and unregulated. The fishing pressure on sharks, combined with their slow rate of reproduction, means that they are being overfished.

The solution would seem simple: reduce the number of sharks and rays we kill. But a major obstacle to conservation efforts is our limited understanding of sharks. We simply don’t properly understand their behaviour, breeding habits or migration patterns. For most shark species, we don’t even know how many of them there are! Without this basic knowledge, we can’t accurately calculate fishing limits and develop other effective conservation measures to conserve them. That’s why the Save Our Seas Foundation funds the basic research into sharks that is so desperately needed.