ZSL ran another of its events last Tuesday, this time about shark conservation and legislation. The speakers – Fiona Llewellyn, Alison Perry and Sarah Fowler – were three of the best I’ve seen at these events. They spoke about the current challenges facing shark conservation efforts.
Sharks are amazing. But they’re not easy to study, and they’re declining at an alarming rate. Here’s why:
Despite having been around since at least the Cretaceous period, sharks are disproportionately vulnerable to overfishing. The main reason for this is their slow life history, particularly some of the weird deep sea sharks. Female gulper sharks aren’t sexually mature until they’re 12-16 years old, and they produce one pup after a two-year gestation. Even left completely alone, it would take gulpers 55 years to double their population (as a random comparison, elk in national parks have a population doubling time of 3.6 years). As Sarah Fowler from the Marine Biodiversity Conservation Policy put it: “they’re not set up to be eaten by anything else, they usually do the eating. Once they’re down they tend to stay down.” Depletion of prey, habitat loss and climate change all affect sharks, but by far the largest threat is overfishing.
We’re only just figuring out how bad the situation is. The IUCN Red List Specialist Shark Group currently classifies 17% of shark and ray species as Threatened, but we know so little about these animals that 47% of species are classified as “data-deficient”. If you correct for the gaps in the data by using size and location to determine the likely danger level for those species, it’s likely that 24% of all shark and ray species are threatened. This is worse than any other vertebrate group except the amphibians. And it’s on our doorstep – some of the worst regions and most endangered species are in the Mediterranean.
So why are sharks being fished? The practice of finning for shark-fin soup is well known, but Alison Perry from Oceana highlighted the main threat to deep sea sharks: their livers contain an oil called squalene. Squalene is lighter than water and is part of the shark’s buoyancy system, but it’s commercially valuable and shark liver can fetch up to £9 per kilo. Up to six million deep sea sharks are killed each year for their livers, with the rest of the shark often being discarded.
Around 90% of this squalene (or the processed form squalane) is used in cosmetics – as a moisturising component in face creams, lipsticks and hair conditioner. 9% is destined for herbal medicines and supplements (the use of which has little basis in evidence), and less than 1% is used as an adjuvent in vaccines such as the ‘flu vaccine. The depressing thing about the cosmetic use is that you can extract squalene from olives and other plants – and some companies do – but the labels won’t tell you the source of the squalene in your moisturiser. A quick and unscientific survey by me at the local shops found that there are many products free of squalene, but the higher-end cosmetics that did contain it all failed to note the source. A 2011 study conducted by Jame et al in France identified shark squalene in 6 out of 8 skin creams they tested. Incredibly, it costs more to extract the substance from plants than it does to buy shark livers.
Case studies on the effect of this fishing are grim. The leafscale gulper and Portuguese dogfish in the North-East Atlantic started to be fished in the 1970s. By 2002 the fishermen were having to trawl deeper and deeper. A 2005 report estimated that the populations had dropped by 62-99%.
So what can be done? Fiona Llewellyn from ZSL’s Marine Conservation Team spoke about the Marine Protected Areas (basically nature reserves at sea). It can be difficult to ensure that highly mobile or migratory species benefit from them – if a shark swims over 7000 kilometres in 5 months, across international boundaries, how do you enforce a hunting ban or protect a population? At present only 2.7% of the range of the endangered whale shark is protected. We could improve the effect of these reserves by collecting more data on shark lifestyles and acting upon it to protect the most important areas, such as feeding or breeding grounds.
In June this year the EU strengthened the regulations against finning, meaning that sharks caught for their fins have to be brought back to shore with the fins still attached. This makes quotas enforceable and allows us to collect accurate data about species and number of sharks.
On Tuesday, the European Commission voted on a fisheries proposal that could be important for Europe’s sharks. They passed tougher legislation on quotas, restricted areas and the urgent need for environmental impact assessments and data collection. Unfortunately campaigners failed (by a narrow margin) to push through a prohibition on trawling below 600 metres. After lobbying from the fishing industry, the EU also rejected calls to place further shark species in the “most vulnerable “ category, and close loopholes in the deep sea shark fishing restrictions.
The questions after the presentations focussed on the future. All of the speakers agreed that although the shark situation is urgent, there is hope. Public awareness is increasing, and public awareness drives policy (at least in the EU). Although the minutiae of fisheries legislation may baffle most people, there is a clear message for consumers about the squalene in our cosmetics. Simply raising public awareness and labelling moisturisers with the source could help the deep sea sharks immensely.
Interesting shark links:
- The IUCN shark specialist group.
- Future ZSL Science & Conservation Events.
- The Shark Trust have great factsheets for UK shark species (there are more of them than you might think).
- The EU statement on the recently reformed Fisheries Policy.
- The above-mentioned 2011 study has a good summary about squalene, and analysis of commercial facecreams to determine squalene origins: Jame, P., et al, “Differentiation of the Origin of Squalene and Squalane Using Stable Isotopes Ratio Analysis,” SOFW-Journal. Jan/Feb 2010;136:1-7
- How to make an origami shark.