Marine Life & Conservation
Diving with British Marine Life: The John Dory

Part 1 of a new series by our latest blogger Georgie Bull…
A few years ago, I attended a work experience placement at the London Aquarium. During a school session, the staff members gave the children a group of 20 photo cards and asked them to choose which ones they thought showed native species. The cards pictured the likes of corkwing wrasse, orca, basking sharks, cod, whiting, mackerel, and vibrant nudibranchs. Of these, colourful species were seldom selected. At the end of the activity, it was revealed that all the cards showed permanent or seasonal UK residents, which was met with shock from both the pupils and staff.
From this experience, and many more like it, I’ve come to realise just how underappreciated British marine life is.
Over the next six blogs, I will explore just a handful of the charismatic species encountered in the South West of England. I aim to introduce each species, describing my encounters with them before highlighting any relevant literature. There is still so much we don’t know about the species living on our doorstep.
In the build up to my first night dive at Chesil Cove last year, sighting reports circulated that john dory (Zeus faber) were seemingly everywhere. This species had been on my ‘to see’ list for quite some time so any likelihood of seeing one filled me with excitement. Halfway through the dive I noticed a faint, but frantic undulation centred around what looked like a large grumpy dinner plate. It was indeed a john dory. This individual was so full of expression that I found it hard not to fixate myself for the duration of the dive! This was the start of what became a frequent occurrence throughout the season.
Profile
As well as their false eyespot, elongate fins, and disc like body, john dory demonstrate distinctive behaviour in the water. Their movement is relatively slow, though their soft anal and dorsal fins (positioned behind their spined counterparts) move frantically to alter their position in the water. While small, their mouth is capable of rapid extension to draw in prey, and they’ll manoeuvre their bodies into all sorts of strange positions in the water to do so.
Zeus faber are often associated with warm water, but their distribution conflicts this idea, with their Northern range extending as far as Norway!
John dory are categorised as data deficient by the IUCN. The IUCN ranks species based on their population trends, and they are particularly famous for their ‘Red List’ which categorises endangered species. Sometimes insufficient information is available, and the organism is regarded as data deficient. As this is the case for the john dory, questions arise about how their population is coping with its value to the fishing industry.
Literature
It’s true that anglers and divers value john dory, but scientists have been finding out more about the species in recent years. One of their most distinctive features is the false eyespot. These spots are found in a variety of organisms from butterflies to lizards and are thought to divert predator attacks to less essential parts of the body (e.g. the tail) which may offer increased chance of escape. The role of eyespots in nature is understudied, but lab experiments in 2011 and 2013 showed that predators were inclined to attack eyespots spots more so than other areas of the body. This provided evidence in favour of eyespots acting as attack diversions.
On a different note, sound in the marine environment is receiving increased attention recently. Iconic footage captured by the BBC for Blue Planet 2 of reef noise, or hot topics like noise pollution from boat traffic are taking centre stage. But sound in the marine environment is used by individuals to communicate in a variety of different ways. John dory create sounds with sonic muscles that surround their swim bladder. Until 2018, this sound had only been recorded in air. A study recorded the species using baited remote underwater video (BRUV) footage and found that individuals would make the sound when predators were near. This caused predators to flee, suggesting the sound could serve as a territorial defence mechanism. As with all species, there are still many aspects to the life of john dory that we are only just beginning to understand.
References:
- https://www.iucnredlist.org/species/198769/42390771
- https://www.marlin.ac.uk/species/detail/1542
- https://royalsocietypublishing.org/doi/full/10.1098/rspb.2013.1458
- https://link.springer.com/article/10.1007/s00265-011-1173-7
- https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0204647
Hear more from Georgie here: https://georgiebullphotography.home.blog/
Marine Life & Conservation
Make Every Dive Count

The Shark Trust Great Shark Snapshot is back for its 4th year! And this time the Shark Trust are asking you to Make Every Dive Count!
The last week of July will see the return of the Shark Trust’s citizen science initiative: The Great Shark Snapshot. It encourages divers and snorkellers, all around the world, to record the sharks and rays that they see. This year it takes place between the 19th and 27th July. Get ready to dive in!
The event is back for its 4th year, and it is happening in “Shark Month”, more commonly known as July! To coincide with a series of events that celebrate all things shark and ray, including Shark Week and the 50th anniversary of Jaws.
Divers, clubs, centres, charter boats and liveaboards are all encouraged to show their support by organising dives and events throughout the week. As well as gathering vital data, the event will provide a chance to celebrate the incredible shark and ray species that live in our ocean.
Information about the species and numbers of sharks and rays the participants find over the week will be added to the Shark Trust’s Shark Log. This global shark census will, over time, allow shark scientists to build a picture of species distribution and any changes that occur
Caroline Robertson-Brown, Marketing Manager at the Shark Trust said “It is great to see this popular citizen science event back for its 4th year. We are asking divers to Make Every Dive Count this year. To identify. Count and Record every shark, ray and eggcase they see during the week-long event. To organise dives especially to take part. Whether you are diving your local dive site, or on a trip of a lifetime, we want divers to join in on the Great Shark Snapshot in July.”
It is easy to join in. Just go diving between 19th and 27th July and record every shark, ray, skate or eggcase that you and your dive group sees. If possible, take photos and some video footage too. Then make sure that you record your sightings on the Shark Trust Shark Log recordings website or by using the Shark Trust app.
This year we have created a digital guide that puts all the information you need in one handy online guide. Which can be downloaded from the website.
The Great Shark Snapshot is a way for divers to get together, go diving, and do something to help shark conservation. Why not dive in?
Find out more here: www.sharktrust.org/snapshot
Blogs
The Ocean Cleanup Launches 30 Cities Program to Cut Ocean Plastic Pollution from Rivers by One Third by 2030

The Ocean Cleanup, the international non-profit with the mission to rid the world’s oceans of plastic, has announced, at the UN Ocean Conference (UNOC), its plan to rapidly expand its work to intercept and remove ocean-bound plastic pollution.
The 30 Cities Program will scale the organization’s proven Interceptor™ solutions across 30 key cities in Asia and the Americas, aiming to eliminate up to one third of all plastic flowing from the world’s rivers into the ocean before the end of the decade.
This evolution follows five years of learning through pioneering deployments across 20 of the world’s most polluting rivers and represents a key next step in the organization’s mission and the global fight against ocean plastic pollution.
With the 30 Cities Program, The Ocean Cleanup will transition from single river deployments to citywide solutions, tackling the main plastic emitting waterways within each selected city. This follows a key learning from deployments in Kingston, Jamaica, which showed it is possible to scale faster when projects encompass whole cities, as the same set of partners can be involved with all deployments.
To date, The Ocean Cleanup has already prevented 29 million kilograms of trash from reaching the ocean. The organization currently intercepts an estimated 1–3 percent of global river-borne plastic emissions. With the first 20 river deployments close to being fully operational, it is now poised to reduce the plastic pollution flowing into the ocean from rivers by up to a third.
“When we take on an entire city, instead of individual rivers, we can scale faster, reduce costs, and maximize impact,” said Boyan Slat, Founder and CEO of The Ocean Cleanup. “Our analysis shows that strategically deploying Interceptors across just 30 carefully chosen cities can stop up to a third of river plastic pollution worldwide. This is the next big leap toward our ultimate goal of a 90 percent reduction in global ocean plastic pollution.”
City-by-city: a Faster Path to Scaling
Using the latest scientific modeling and on the ground experience, The Ocean Cleanup identified 30 major plastic polluting coastal cities which include:
• Panama City, Panama – First deployment to go live in the coming months.
• Mumbai, India – Mapping of all waterways completed; preparations for first deployments underway.
Furthermore, the organization is developing plans to expand on its existing work to all polluting rivers in:
• Manila, Philippines; Montego Bay, Jamaica; Jakarta, Indonesia; Kuala Lumpur, Malaysia; Bangkok, Thailand and Los Angeles, U.S.A.
Other cities will be announced once the necessary partnerships and agreements are in place. Planning and fundraising activities are underway for all 30 cities. To realize these ambitious plans, the organization is currently also expanding its engineering and operational capacity.
Data Driven Restoration at Scale
Before Interceptors are deployed, each city project begins with an intensive analysis phase. Aerial drones, AI-powered image analysis, and GPS-tagged “dummy” plastics are used to chart every visible waterway and track how waste moves from streets to sea. These real-time insights guide optimal Interceptor placement and provide a public baseline against which progress can be measured.
Alongside intercepting new plastic, the 30 Cities Program will also remove debris from nearby coasts, mangroves, and coral reefs. This twin-track approach—shutting off the tap while clearing the legacy pollution—enables The Ocean Cleanup to achieve long-term impact, which includes the restoration of fish nursery habitats, boosting coastal tourism, and strengthening of natural storm surge defenses for local communities. Alongside local partners, the organization also advocates for improvements in waste management and awareness raising amongst communities.
Completing the First 20 Rivers
While laying the foundation for the 30 Cities Program, The Ocean Cleanup is also nearing completion of its first 20 river projects. The next landmark achievement—expected as soon as the second half of this year—is in the western Caribbean, where the team aims to resolve the plastic pollution problem in the Gulf of Honduras by intercepting the trash feeding into this body of water.
A Stepping Stone Toward a 90 Percent Reduction
The 30 Cities Program represents the first major scaling step in The Ocean Cleanup’s journey to eliminate 90 percent of floating ocean plastic pollution. In parallel, efforts are continuing to remove plastic from the Great Pacific Garbage Patch. Whilst extraction operations are currently on hiatus, work to deploy cutting edge technologies to map the “hotspots”, or areas of intense plastic accumulation, in order to make future extractions more efficient and economical, is ongoing.
By combining river interception and coastal cleanup with its offshore cleanup systems targeting legacy pollution that’s already in the ocean, the organization is charting a path to turn off the tap and mop up the mess.
About The Ocean Cleanup
The Ocean Cleanup is a nonprofit organization that develops and scales technologies to rid the oceans of plastic. By conducting extensive research, engineering scalable solutions, and partnering with governments, industry, and like-minded organizations, The Ocean Cleanup is working to stop plastic inflow via rivers and remove legacy plastic already polluting the oceans. As of June 2025, the non-profit has collected over 28 million kilograms (62 million pounds) of trash from aquatic ecosystems around the world. Founded in 2013 by Boyan Slat, The Ocean Cleanup now employs a multi-disciplined team of approximately 200 people. The organization is headquartered in Rotterdam, the Netherlands, with international operations in 10 countries. For more information, visit www.theoceancleanup.com.
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