In this month’s Ocean Brief, we look at some of the efforts being made to tackle noise pollution from marine vessels, the UK's raw sewage problem, and how some fish can recognise individual divers.
A reason for hope
There’s no doubt about it. Thanks to us, the ocean is getting noisier. For marine life, that’s not great news. Noise pollution can disrupt animal communication, hunting, finding a mate, and more. Noise pollution in the ocean comes from lots of different sources - like ships and boats. In fact, the noise generated by marine vessels has its own name - underwater radiated noise. As more and more vessels head out to sea, the more underwater radiated noise becomes a problem.
Which is why the Quiet Vessels Initiative is so important.
Funded by Transport Canada, the Quiet Vessels Initiative funds research and development projects that are looking for ways to reduce noise from vessels. Some of the projects have looked at new designs and technologies, some at how to retrofit existing vessels, some at operational practices, and some at how we even measure underwater radiated noise from vessels in the first place.
It’s been a huge undertaking. Thankfully, Clear Seas, a Canadian non-profit that specialises in marine shipping issues, has teamed up with Transport Canada (and myself) to pull all these projects together into a series of articles. The first of those articles, which looks at measuring underwater radiated noise from vessels is out now.
Credit: ClearSeas
Something to work on
In 2024, Dr Jonathan Cox, a microbiologist at Aston University, contracted a lung infection. The cause? Probably raw sewage in the sea where he had been swimming.
Jonathan isn’t the first to have contracted something unpleasant from raw sewage in the sea around the UK, nor will he be the last. The UK’s raw sewage problem has been an issue for years, and it’s only getting worse. This, Jonathan wrote in an open-access review article for the journal Microbiology, needs to change.
Jonathan’s call for urgent investment follows calls from others like Surfers Against Sewage, who have been campaigning on the issue for years. To be fair, it is an extremely expensive and technically challenging issue to solve, and requires stricter regulation over the companies that are dumping raw sewage into the sea. But make no mistake - this is fixable. As with most things, the sooner action is taken, the cheaper it will be.
Jonathan says, ”Whilst we’re waiting for the improved management, innovation and investment that is required to solve the issue and save our seaside, don’t bury your head in the sand regarding water quality. Check before you swim. After all, prevention is always better than cure.”
I’d also add that, if you live in the UK, writing to politicians, attending meetings (if you can), or even supporting organisations tackling raw sewage is really important.
➡️ Read the open-access article
➡️ Visit Surfers Against Sewage’s website
➡️ See where UK sewage is discharging into the sea right now
Something we’ve learned
This is a pretty neat discovery by Maëlan Tomasek, Katinka Soller, and Alex Jordon, from the Max Planck Institute of Animal Behaviour; Wild fish in the Mediterranean Sea can recognise individual divers.
Well, more precisely, saddled sea bream (Oblada melanura) and black sea bream (Spondyliosoma cantharus) can recognise divers by their dive gear.
Let’s step back a bit. It’s not unusual for scientific divers studying marine animal behaviour to use food as a reward in experiments. At the STARESO research station in Corsica, France, scientific divers carrying food rewards noticed that certain fish started following them around, ignoring all other divers. Thus, an experiment was born to see if the fish really were able to tell the individual divers apart.
First, Katinka Soller put on a bright red vest and fed fish as she swam for 50 metres. After a number of dives, Katinka removed the red vest, hid the food, swam for 50 metres, then fed the fish who followed her. Twelve days later, 20 fish were regularly following Katinka.
Next, Maëlan Tomasek entered the water. Maëlan’s dive gear was a bit different from Katinka’s - like different colour fins, and different colours and patterns on the wetsuit. Both divers would start at the same point and swim off in different directions. After 50 metres, Katinka would feed the fish that followed her. Maëlan never fed the fish. On the first day, the fish split, following both Maëlan and Katinka. Over time, more and more fish followed Katinka.
But what would happen if both divers were wearing identical dive gear? That was the final part of the experiment. The result - the fish didn’t follow Katinka, who had the food, more than Maëlan. This, the researchers say, suggests that the fish use visual cues like colours and patterns to identify the divers.
What else caught my eye
For early career ocean professionals, at-sea training can be extremely valuable. The @SeaNetwork (All-Atlantic Floating University Network) is looking to strengthen and develop training opportunities across the Atlantic Ocean.
In 2022, the Russian Federation was temporarily suspended from participation in ICES activities. Now, the Federation has decided to leave ICES.
Curious to know how much seafood Europeans are eating? The latest Eurobarometer survey has the answers.
The Institute of Marine Engineering, Science & Technology and the UK Department for Environment, Food & Rural Affairs (Defra) have formed a partnership to help guide innovation in marine mammal monitoring.
Researchers at the University of Exeter have found green and loggerhead turtles are nesting earlier in Cyprus to avoid rising temperatures.
Researchers from Te Herenga Waka—Victoria University of Wellington have discovered a species of sea squirt that is thought to be new to science!
Curious to know how the UN Ocean Conference and One Ocean Science Congress are related? This is for you.