“Sharks are beautiful animals, and if you’re lucky enough to see lots of them, that means that you’re in a healthy ocean. You should be afraid if you are in the ocean and don’t see sharks.”
– Sylvia Earle
Overexploitation
Oceanic whitetip shark by Clare Shenstone
Wildlife populations around the world are declining and many species are being pushed towards extinction. Alongside the loss, degradation and fragmentation of habitats, overexploitation is one of the most significant drivers of a crisis that some scientists are calling the sixth mass extinction.
Human beings have always exploited the natural world, but in our more recent history the reach and impact of this exploitation has grown exponentially: as the world’s population has exploded, mechanisation and technological advances have brought deadly efficiency to our ability to hunt, fish and harvest the species with which we share the planet.
Overexploitation can be defined as “exploitation of (removal of individuals or biomass from) a natural population at a rate greater than the population is able to match with its own recruitment, thus tending to drive the population towards extinction.”(1) A recent paper published in the journal Nature looked at over 8000 species that appear on the IUCN Red List of Threatened species, and found that “72% of (threatened and near-threatened species) are imperiled by overexploitation.”
‘There’s enough on this planet for everyone’s need, but not for everyone’s greed.’ Gandhi
This harvesting of species is happening at an unprecedented scale. Tens of thousands of species and the products derived from them are removed from the wild each year, both alive and dead, as rates of consumption are growing, alongside the growth in human populations. The wildlife trade – legal and illegal – is worth billions of dollars annually.
In ecosystems around the world – forests, rivers, lakes, oceans, wetlands and savannahs – species populations are being steadily pushed to the point of exhaustion or extinction: “It is estimated that overexploitation is a major threat to at least one-third of threatened birds and amphibians, with wildlife currently extracted from tropical forests at approximately six times the sustainable rate.” (2)
Empty oceans
The oceans are one of the world’s most severely overexploited ecosystems. As the fishing industry has increased its ability to fish further and deeper, using state-of-the-art technology to locate dwindling shoals of fish, and the demand for fish as a source of protein has soared, some of our most important marine species are in danger of disappearing altogether.
Anecdotal and photographic evidence of the extent of this decline paints a disturbing picture. To listen to stories told by people whose lives have been inextricably linked with the oceans for decades is to hear of an abundance of marine wildlife that is unimaginable today. Literature and ships’ logs describe seas with far greater concentrations of large fish and marine mammals in the 19th and early 20th centuries. The Living Blue Planet Report, 2015, found that marine populations have dropped by almost 50 per cent since 1970, while the Food and Agriculture Organisation (FAO) reports that around 90% of the world’s fish stocks are either fully fished or overfished.
This systematic emptying of the world’s oceans comes at a huge cost, not just for the fisheries’ target species, but also for countless other marine species – caught as bycatch – as well as those that depend on a functioning marine food web, including ourselves.
The Oceanic whitetip shark (Carcharhinus longimanus)
As many as 100 million sharks, possibly more, are taken from the oceans each year, a level of exploitation that is pushing many previously abundant species to the brink of extinction. The Oceanic whitetip shark, Carcharhinus longimanus (the name means ‘long hands’), used to be one of the ocean’s most abundant pelagic predators, yet now, in some parts of the ocean, it has disappeared completely, whilst throughout its widespread range it is listed as Vulnerable on the IUCN Red List of Threatened Species*. Sharks are particularly vulnerable to population collapse as they tend to reach sexual maturity late, females have long gestation periods and give birth to a relatively small number of offspring.
Industrial fishing for species such as tuna results in millions of oceanic sharks being caught as bycatch. The fins of the Oceanic whitetip are particularly large, which unfortunately makes them prime candidates for shark fin soup in and thus highly prized by the Asian market for shark fin soup. When caught, their fins are generally hacked off, and their carcasses thrown back into the sea.
As one of the oceans’ apex predators, sharks play a pivotal role in marine ecosystems. When sharks disappear, predator-prey relationships lower down the food web can change dramatically, affecting other species but also sometimes the fisheries that communities depend on. These interconnected systems are so complex that it is nearly impossible to predict how the marine ecosystem will react to losing its predators.
Combatting overexploitation
The diversity of threats to species from overexploitation calls for a range of responses. Challenges in the marine environment include: overfishing – the severity of which is likely even worse than we think due to vast underestimation of catch rates, Illegal, Unregulated and Unreported (IUU) fishing, bycatch, lack of regulation on the High Seas, and poor coverage, enforcement and monitoring of Marine Protected Areas (MPAs),. and underestimated catches, particularly from small-scale, artisanal fisheries.
Synchronicity Earth supports organisations taking effective action to combat these threats. The Shark Trust has been lobbying for greater protection for sharks and rays since 1997, contributing to notable successes along the way: since 2013 all sharks caught in European waters must be landed with fins naturally attached (instead of cutting off the fins and discarding the carcasses at sea). Our support helps Shark Trust to continue its advocacy work and to develop public awareness-raising campaigns in zoos and aquaria throughout Europe.
Lobbying and advocacy is at the heart of the work of Bloom, the Deep Sea Conservation Coalition and the High Seas Alliance. These organisations and coalitions are leading efforts to tackle some of the most profound challenges of overexploitation and to protect marine biodiversity and resources.
Synchronicity Earth also supports organisations working to tackle overexploitation on a more local level, in coastal communities to develop more sustainable fisheries, protect marine ecosystems and improve the lives of local people in coastal communities. Blue Ventures has pioneered a social entrepreneurship approach in Madagascar and beyond, introducing Locally-Managed Marine Areas (LMMAs) to create more sustainable fisheries. OneReef are developing bespoke models in Micronesia linking local communities to international donors to protect coral reefs and fish stocks from IUU fishing whilst helping to develop sustainable livelihoods.
Conclusion
The systematic removal of species from the world around us damages biodiversity and ecosystem health; and it profoundly affects human prosperity and wellbeing. If we want to slow down and reverse the trend, “we have to recognise that our impact is game-changing on this planet, that we are all responsible, and that we have to become stewards of nature – as a part of it, rather than behaving like children rampaging through a sweetshop.” (3)
Nevertheless, it is important not to lose sight of the successes that effective conservation can achieve. Identifying and supporting a range of actions that deliver the greatest impact and can be scaled up is vital if we want to conserve the unique species and ecosystems on which we depend.
Sources:
1 Townsend C., Begon M., & Harper J. (2008) Essentials of Ecology, 3rd Edition. Blackwell Publishing, Oxford
2 Sodhi N.S, Brook B.W, & Bradshaw C.J.A. (add full ref2009) Causes and Consequences of Species Extinctions. The Princeton Guide to Ecology, 2009 / pp.514-520. Accessed 13.01.17, https://press.princeton.edu/chapters/s5_8879.pdf
3 Williams M. cited in Hance, J. (2015). How humans are driving the sixth mass extinction. The Guardian. Accessed 13.01.17,
https://www.theguardian.com/environment/radical-conservation/2015/oct/20/the-four-horsemen-of-the-sixth-mass-extinction.
You might also like:
Find out more about our High and Deep Seas programme
For detailed data on fisheries, the Sea Around Us website is an excellent place to start
The Ravages of Guns, Nets and Bulldozers (Nature)
Our seas are being degraded, fish are dying – but humanity is threatened too (Callum Roberts, writing in the Guardian)
To watch:
The End Of The Line – Where have all the fish gone? 25min Version from Blue Marine Foundation on Vimeo.
Sylvia Earle: Ideas for Change
* ® The IUCN Red List of Threatened Species is a registered trade mark of IUCN.
