Octopus, Orcas and Oysters: how the UK's marine environment is changing

The UK's marine life could change substantially over the coming years as sea temperatures continue to rise. Various species of shark, octopus and tuna, normally found in warmer climes like the Mediterranean, could all start to appear in the waters around the country in greater numbers.

But, such a dramatic change could have negative knock-on effects on the UK's ecosystem, with some native species likely to struggle to adapt.

What kinds of marine life could appear?

There have already been recordings of unfamiliar types of sharks, octopuses, jellyfish and rays recently appearing in UK waters as sea temperatures rise and provide hospitable living conditions and access to prey.

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These species could all boom as conditions change, as could some more static marine life, such as native oysters, according to researchers at the Centre for Environment, Fisheries and Aquaculture Science (Cefas), who analysed how 19 threatened marine species could respond to climate change. Among the "biggest winners" are "native oysters, basking sharks, spurdog sharks, and thornbacks", said the BBC.

But the researchers also identified species that could struggle to adapt in the changing seas, mostly static creatures, including the small seafloor-dwelling invertebrates, sea pens and the ocean quahog, a type of clam that can live up to 500 years.

How much is the environment changing?

Sea temperatures have been hotter than usual in recent weeks due to the extended surge in heat in the UK during spring. Some areas have been recorded as much as 4 degrees warmer this year, with potential negative implications for marine life, the longer it goes on.

This may be a temporary heatwave that we're currently experiencing, but the greater concern is that climate change is causing marine heatwaves to happen more often and potentially become more intense.

What are the possible consequences?

There is no conclusive evidence as to how sustained higher temperatures could affect marine life, but it could disturb current breeding patterns and bring other species like jellyfish en masse into UK waters, as well as harmful algae.

It could signal an immediate gain for British fishermen as more fish and other species like octopus arrive in the warmer seas, but that could also bring with it more predators. It's not even "unreasonable to think" that great white sharks could start to pop up off UK shores, with "plenty of potential prey" in seals and sea lions and "suitable water temperatures", said Discover Wildlife.

Changing marine life could then lead to more Marine Protected Areas (MPAs) being implemented by the government, something that has caused consternation among commercial fishermen, worried it would prevent them from using the controversial bottom trawling method to catch fish.

There will also likely be a closer look at how humans interact with the changing wildlife. Earlier this month, Police Scotland appealed for information after a speedboat "deliberately disturbed" a pod of orcas on the Moray Coast. Orcas are not uncommon in the summer months around the coast of Scotland, but they have been "spotted earlier and later" than usual in recent years, said The Press and Journal.

What action is being taken?

The Labour government has already proposed to expand a ban on bottom trawling, which involves dragging large nets along the seabed, across thousands of miles of 41 MPAs. The ban is subject to a 12-week consultation, but conservationists are concerned that trawling is harmful to rare marine animals and their habitats. It can also release huge amounts of carbon dioxide from the seabed each year, potentially accelerating climate change.

Research is also taking place at the University of Plymouth and Exeter to try and counter drastic changes to marine life through climate change. Scientists in Devon and Cornwall are examining whether huge numbers of mussels can help restore habitats, acting as natural biofilters for harmful algae, for example. Other research is also looking at whether certain microscopic marine fungi can have a wider effect on climate change on land and sea, being able to absorb large portions of carbon dioxide from the atmosphere and slow down climate change.