100 million or more sharks are being lost every year. Sharks are being killed for their valuable fins (which are seen as a delicacy in some parts of the world) or are taken up by accident in the process of catching other species. Studies have found that sharks are vulnerable to even a light fishing pressure. In the North sea and around the British isles, trawl fisheries have reduced most large shark species to under detectable levels. Like humans, they are slow-growing and have few offspring, meaning that populations cannot make up for the numbers lost by fishing, so are in significant decline.
We do not yet know the full effects of the declines in shark numbers, but it is expected to significantly impact marine ecosystems, as sharks have a vital role as top predators. Their removal can cause cascading effects throughout the food chain – species which sharks feed on could increase in number and range, which would in turn increase predation on species which these animals feed on, which includes some commercially important fish.
Egg cases can be removed from dead sharks and, if kept in the right conditions, hatched to produce live shark pups. However, in the past, these pups were just used for observation. Greg Nowell, co-founder of non-profit organisation Shark-Lab Malta, has taken a new approach to shark conservation, and has successfully reared shark pups hatched from egg cases taken from dead sharks in fish markets.
Almost 300 sharks have been hatched, reared and released into the wild this way. The species chosen for this project (the lesser spotted dogfish and bull huss) are ideal as they are oviparous (egg-laying). Provided that the sharks have not been frozen on their way to the fish market, the egg cases are viable outside of the bodies of their mothers.
The work has been taking place at Malta National Aquarium. This means that the public can also get involved, which results in more awareness of shark conservation. When each of these sharks has been released into the wild, the public have come to watch. The public watch the sharks in shallow waters for a short amount of time before waving them off as they are taken to a deeper, more suitable habitat (using equipment donated by local dive clubs), where they are released by volunteers.
Even though the actual number of sharks being returned to the sea is negligible in terms of having a significant impact on wild populations, this means that the project draws public attention and encourages cooperation with relevant businesses, such as dive schools and aquariums. The hope is that increased public support for the shark conservation effort will translate to increased support for policy action to protect these animals.