Time to celebrate our natural biodiversity but also to recognise the trouble it’s in

May is a special month for the environment as we celebrate Endangered Species Day on the 21st and Biological Diversity day on the 22nd. These two days are inextricably linked and also have strong implications for sharks and rays, and even for ELMO.

Our world is a wondrous place filled with biological diversity – a whole range of creatures, big and small, fluffy and scaly, scary and awe-inspiring. Biodiversity refers to every living thing, including animals, plants, bacteria and of course humans. Back in 2011, scientists estimated that there are roughly 8.7 million species of plants and animals on our planet! All of these wondrous species have evolved together and work together to survive and maintain the places they live in (i.e. ecosystems). Additionally, many species also provide important benefits to us as humans, including medicine, food and clothing.

Biodiversity represents all variety of life on earth - from big to small, fluffy to scaly, and everything in between. Image created by Chantel Elston

The sad side of the story is that human activities have permanently altered this biodiversity. Pollution, climate change, consumption and population growth all disturb and destroy ecosystems and the biodiversity within them. These threats have caused an alarming rate at which species go extinct, with most scientists believing we are in the sixth mass extinction event (to put this into perspective, the dinosaurs were wiped out by a mass extinction event).

Because of human activities, threats like pollution and climate change have lead many scientists to believe we are currently living through the 6th mass extinction event, with alarming numbers of species becoming extinct. Image created by Chantel Elston.

With each species that goes extinct, we lose some link in the ecosystem they lived in, which can have serious repercussions for the remaining biodiversity. Also, each lost species represents a lost treasure trove of solutions to our problems, including potential cures for diseases, inspiration for new technology, sources of new materials, and so much more.

One of the groups of animals that represents both biodiversity and extinction risk the best are sharks and rays, the animals we hold most dear here at ELMO. This is because sharks and rays represent one of the most biodiverse groups of animals on our planet, but they are also one of the most threatened.

There are over 1000 species of sharks and rays alive today. Unfortunately, the first global assessment conducted by the IUCN Red List of Threatened Species in 2014 estimated that one-quarter of sharks and rays were threatened with extinction. This made them the most threatened vertebrate lineage after amphibians!

The first global assessment was conducted on sharks and rays in 2014 and found that 25% of species were considered at risk for extinction, making them the second most threatened group of animals. Image created by Chantel Elston.

Sharks and rays are among the slowest maturing and reproducing vertebrates, with some of them having the longest gestation periods and highest levels of maternal investment in the animal kingdom. One example is the basking shark, which has a gestation period of 44 months (that’s longer than an elephant)! This makes it very difficult for them to replenish their numbers if they decline.

Couple this with the strong fishing pressure that sharks and rays face, means we have a serious problem. In many parts of the world, fishing pressure on sharks and rays has been increasing because their meat, fins, livers and/or gill rakers' are of high value. In response to this fishing pressure, their populations have plummeted. Shark and ray landings reported to the Organisation for Food and Agriculture of the United Nations (FAO) steadily increased to a peak in 2003 and has since been declining by 20%, simply because there are not as many animals to catch as there once was.

Sharks and rays provide a unique perspective on the state of the oceans and their protection and conservation will have large effects on many broader problems: protecting the health of our sea and ensuring that ecosystems continue to function and thrive, providing food security for the world, and economic stability for many people. And the same is true for the remaining 1 million animal and plant species that are considered at risk for extinction.

So this month, as we celebrate both Endangered Species Day and Biological Diversity Day, let’s take a moment to pause and appreciate the natural beauty and resources that the earth offers us every day. Whether it’s wondering at the beauty of the flowers in your garden, or being enraptured by the birds that flit about, or even being inspired by the marine diversity you can encounter in a simple rock pool. But let’s also recognise the footprint we as humans leave behind us on this natural beauty, let us recognise that because of our direct actions, many of these species are at serious risk for extinction, and let’s try to all share this wonderful planet we call home.

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References:

Mora, C. et al. (2011) How many species are there on earth and in the ocean? PLoS Biol 9(8): e1001127

Dulvy, N. K. et al. (2014) Extinction risk and conservation of the world's sharks and rays. eLife: eLife 2014;3:e00590

Geballos, G. et al. (2020) Vertebrates on the brink as indicators of biological annihilation and the sixth mass extinction. PNAS 117(24)