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Marine Life & Conservation

Marine Conservation Society’s report shows increase in jellyfish sightings on UK and Irish shores




The Marine Conservation Society has released its annual Wildlife Sightings report, marking World Jellyfish Day on Friday 3rd November.

The charity’s wildlife sightings project focusses on gathering reports of jellyfish and marine turtles, which feed on jellyfish. These two marine animals are both vital in supporting ocean biodiversity and are indicators of changes in our ocean over time, like warming waters. The charity’s report provides a detailed breakdown of the species observed, revealing the diversity of jellyfish in UK and Irish waters.


This year’s report (covering 1st October 2022 to 30th September 2023) shows a 32% increase in jellyfish sightings compared to the previous year.

Jellyfish can be spotted year-round in UK and Irish seas, but larger blooms are more likely to appear in spring, lasting through until autumn. The Marine Conservation Society’s report shows 75% of sightings were of individuals (1-20), whilst 11% of sightings were of large blooms of over 100 individuals, an increase of 57% from last year.


Research has suggested that an increase in some jellyfish numbers around UK could be related to climate change, however, currently there isn’t enough evidence to make this link. The Marine Conservation Society’s Wildlife Sightings programme aims to collect long term data which can be used as a reference to study the reality of jellyfish trends in UK waters.

Dr Peter Richardson, Head of Ocean Recovery at the Marine Conservation Society, said, “Jellyfish populations are highly variable year on year, and depend on several environmental factors that are different each year, such as sea temperatures and storms. Numbers of sightings we receive can also depend on the awareness of our sightings programme and the ‘wow factor’ of jellyfish people encounter.


“This year seems to have been a particularly good year for barrel jellyfish – one of our chunkiest jellyfish species that can occur in mind-boggling numbers when conditions are favourable. It’s only by observing trends over many years that we can start to suggest reasons for change.”

The most frequently reported species during the reporting period was the barrel jellyfish, which accounted for almost 27% of total sightings (467). This is an increase of 21% compared to the previous year’s results, when it was the sixth most-spotted species. Barrel jellyfish are sometimes called ‘dustbin lid jellyfish’ due to their large size – they can grow up to one metre in diameter. They have a solid, spherical, rubbery-looking bell which can be white, pale pink, blue or yellow. Rather than tentacles, barrel jellyfish have eight thick, frilled arms.

The report features other intriguing jellyfish-like species, including crystal and comb jellies, and sea gooseberries, which made up 10% of the total sightings this year. Crystal jellyfish were the most reported ‘other’ species, accounting for 3.2% of all sightings.


The Marine Conservation Society also records reports of marine turtles, which feed on jellyfish. The charity’s volunteers submitted 12 reports of marine turtle sightings this year, four of which were live leatherbacks. Turtle sightings contribute to a national database.

Six of the world’s seven marine turtle species have been spotted in UK and Irish seas. The leatherback turtle is most likely to be spotted feeding on our jellyfish during the summer months., while stray juvenile loggerheads are usually encountered washed up in winter. The leatherback, which is the largest sea turtle, and loggerheads are considered to be of ‘vulnerable’ conservation status. Reporting sightings of these incredible creatures will support the Marine Conservation Society and others in understanding their movements, potential threats and how better to protect them through policies and conservation strategies.

Other turtle species are swept into UK and Irish seas by strong winds and currents, though more suited to warmer waters. The charity’s Turtle Code provides advice on what to do if a beached turtle is found.


Justine Millard, Head of Volunteering and Citizen Science at the Marine Conservation Society, said, “The data on jellyfish and turtles that volunteers submit plays a vital role in understanding the changes occurring in our marine ecosystems, and help us to protect our seas. We urge anyone who has spotted a jellyfish or turtle to report it to us to continue to build a picture of our seas and the incredible life within them. A huge thanks to all the volunteers who have submitted data to us this past year.”

The Marine Conservation Society uses wildlife sightings by citizen scientists to:

  1. Discover how jellyfish and turtle populations are changing around the UK – specifically when and where they are occurring each year
  2. Investigate trends in turtle sightings to find out more about how they use our waters
  3. Explore whether jellyfish distribution can tell us more about where leatherback turtle feeding grounds may be

For more information on how to identify jellyfish and turtles, and to report a sighting, please visit the Marine Conservation Society’s website:



The life of a Great White Shark



Great White Shark

The great white shark, known scientifically as Carcharodon carcharias, embodies the apex predator of the ocean. This majestic creature’s life is a testament to survival, adaptability, and the intricate balance of the marine ecosystem.

Born in the waters off coastal regions, a great white shark begins its life as a pup within the safety of nurseries, typically found in warm, shallow waters. The pups, measuring around 5 feet in length at birth, are immediately equipped with an innate instinct for survival.

Great White Shark

As they grow, great whites embark on a journey, venturing into deeper and cooler waters, often covering vast distances across the ocean. These apex predators are perfectly adapted hunters, relying on their impressive senses to detect prey. Their acute sense of smell, aided by specialized sensory organs known as ampullae of Lorenzini, helps detect the faintest traces of blood in the water from several miles away.

Feeding primarily on seals, sea lions, and other marine mammals, great whites are known for their powerful jaws lined with rows of razor-sharp teeth. Their hunting techniques often involve stealth, utilizing their streamlined bodies to approach prey from below and striking with incredible speed and force.

Great White Shark

Despite their fearsome reputation, great whites play a crucial role in maintaining the health of marine ecosystems. As top predators, they help regulate the population of prey species, preventing overpopulation that could disrupt the balance of the food chain.

Reproduction among great white sharks is a slow and careful process. Females reach sexual maturity between 12 and 18 years of age, while males mature earlier, around 9 to 10 years old. Mating occurs through complex courtship rituals, with females giving birth to a small number of live pups after a gestation period of about 12 to 18 months.

Great White Shark

However, the life of a great white shark is not without challenges. Human activities, including overfishing, pollution, and habitat destruction, pose significant threats to their population. Additionally, despite their formidable presence, great whites are vulnerable and face dangers from entanglement in fishing gear and accidental bycatch.

Despite these challenges, great white sharks continue to inspire awe and fascination among scientists and nature enthusiasts. Their presence in the ocean serves as a reminder of the delicate balance and interconnectedness of marine life, emphasizing the need for conservation efforts to protect these magnificent creatures for future generations to admire and study.

Want to learn more about sharks? Visit The Shark Trust website:


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Marine Life & Conservation

Book Review: Sea Mammals



Sea Mammals: The Past and Present Lives of Our Oceans’ Cornerstone Species by Annalisa Berta

This is a book packed with information about some of the most iconic and charismatic marine species. I have a particular soft spot for the pinnipeds, seals and sea lions, due to some incredible diving encounters over the years. So these were the pages I first turned to.

Once picked up this book is hard to put down. Polar Bears, Narwhal, Sea Otters, manatees, whales and dolphins adorn the pages with beautiful photographs and illustrations. Each turn of the page lures you in to discover more about a species you love, one you want to learn more about, some you have never heard of and even includes the details of fascinating animals that are sadly now extinct.

I think what I love most about this book is how it is organised. Rather than simply lump the animals into taxonomic groupings, they are put into chapters that tell you a story about them. Whether it is the story of their evolution, how they were discovered, their biology, behaviour or need for conservation. Once you have decided on an animal to delve deeper into, each species has its own story, as well as key information about size, diet, distribution, habitat and conservation status.

There is plenty to enjoy in this delightful book. Plenty to learn too. As the cold dark nights draw in, I can see myself delving into this book time and time again. This is a perfect gift for anyone that loves the ocean and its inhabitants. Or just treat yourself.

What the publisher says:

From the gregarious sea otter and playful dolphins to the sociable narwhal and iconic polar bear, sea mammals are a large, diverse, and increasingly precious group. In this book, Annalisa Berta, a leading expert on sea mammals and their evolution, presents an engaging and richly illustrated introduction to past and present species of these remarkable creatures, from the blue whale and the northern fur seal to the extinct giant sperm whale, aquatic sloth, and walking sea cow.

The book features more than 50 individual species profiles, themed chapters, stunning photographs, and specially commissioned paleo-illustrations of extinct species. It presents detailed accounts of these mammals’ evolutionary path, anatomy, behavior, habitats, and conservation. And because these are key species that complete many food chains and have the widest influence of all sea life, the book also offers insights into a broad variety of marine worlds today and in the future.

About the Author:

Annalisa Berta is professor emerita of biology at San Diego State University. A specialist in the anatomy and evolutionary biology of marine mammals, especially baleen whales, she formally described a skeleton of the early pinniped Enaliarctos. She is the author of Return to the Sea: The Life and Evolutionary Times of Marine Mammals and the editor of the award-winning Whales, Dolphins, and Porpoises: A Natural History and Species Guide.

Book Details

Publisher: Princeton University Press


Price: £25

ISBN: 9780691236643

Published: 26th September, 2023

Pages: 224

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