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Threats to the oceans

Updated: Feb 26, 2021

Walking past Kimmeridge Bay, I visited the Dorset Wildlife Trust and Fine Foundation’s Wild Seas Centre and talked to one of their employees, Sarah, about the biggest threats facing our oceans.


“The biggest threat to our oceans is overfishing. Not just in terms of the fish stocks, but also the equipment, these huge trawlers that you get a lot of bycatch from as well.

That’s something we see on our coastline during the winter in particular. When you get stormy conditions, you get the carcasses of animals washing ashore including dolphins. Some of these are taken away by the Cetacean Strandings Investigation Programme. They carry out necropsies on these animals to find out why they died. A large percentage of them are found to have died through bycatch from these big trawlers. They are not necessarily operating in waters close to our coast, but mainly further off-shore.”

From 1991 to 2017, the biggest cause of death for stranded whales and dolphins was bycatch (Source: Whale and Dolphin Conservation).

“Overfishing, just the level of fish stocks, is also a big problem.”

The Marine Conservation Society estimates that 90% of global fish stocks are either fully or over-exploited. Unfortunately, eating farmed fish instead of wild fish does not necessarily help. If you want to be sure that you are not contributing to this issue, use the Good Fish Guide to find out which fish it’s safe to eat and which it’s best to avoid.

Climate change

“Of course, climate change is the other big threat that’s facing our oceans. We’re already seeing some changes here. There are some climate change indicator species that we monitor here in Dorset. One example is a type of sea snail, a little top shell called a toothed top shell which, as our seas are warming, are migrating from west to east. We’re pretty much on the easternmost limit of their range at the moment, but we are seeing them move further and further east, where the warmer waters from the west mix with the cooler waters coming down from the north and east.”

Plastic sand

While I was talking to Sarah, a girl came in with some nurdles that she had collected from the beach. These are the tiny, smooth pellets that are used to make plastic. Back in 2007, there was a spill of nurdles from a container, and hundreds of thousands of them washed up onto the beach here. The Wildlife Trust aims to remove a million nurdles from the beach by hand, because machine extraction would cause too much damage to the other plants and animals on the strandline.

Nurdles are a problem in the sea and on beaches because they float on the surface, looking remarkably like fish eggs. Seabirds eat them, thinking they are food, and then starve to death with a stomach full of plastic. Other sea creatures have similar problems with them.

Nurdles also accumulate toxins on them, adding to the problems that they cause to any creatures that eat them.

The number of nurdles on the beach here is reducing, but I still found some without looking too hard.

I also found a bio-bead, one of the worst misnomers I have come across. Bio-beads are also small plastic pellets, but they can be distinguished from nurdles by their rough surface. They are used by water companies to treat waste water. The water companies go to some effort to ensure that they don’t lose them, but some definitely escape – the evidence was on the beach. South West Water has eight water treatment plants using these beads. They say that there is no alternative for these sites because their process requires the beads to be buoyant (web page accessed on 1/12/2020). Perhaps it’s time to consider changing the process.

A plastic 'bio-bead' that I found on the beach at Kimmeridge Bay.

What can we as individuals do to resolve these things?

“What we’re trying to do here is to raise awareness of some of these threats that are facing our oceans. I think it’s all about making small changes and if you’ve got lots of people making small changes to their everyday behaviour, whether that’s being mindful of single-use plastic and switching to re-usable items or being more mindful about the fish they’re eating, then all of those things will add up to make a big difference overall.

So, I just think it’s people being aware first of all, and some of these things have been talked about a lot more in recent times. Obviously, the Blue Planet programmes that David Attenborough presented were really good at raising awareness of the issues of marine litter, and although there’s a lot being done around that, there’s still a lot to do.”

Sarah: “I just love the sea. I’ve always lived on the Dorset coast and I’ve spent a lot of time in and on the water. I’m just fascinated by all the marine life around me.”


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