Marine Life & Conservation
Kenna Eco Diving Seahorse Project
Why study seahorses?
Seahorses are strange and mythical creatures that have many unique characteristics. They are classed as “Data Deficient” in CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) because they are very challenging to study in the wild and there is much that we do not know about their secretive lives.
Seahorses represent habitats that need protection and help to advance marine conservation, serving as excellent flagship species for a wide range of marine conservation issues.
Threatened by overexploitation
Seahorses are exploited world-wide in their millions for use in Chinese medicine, as curios, snacks, and for the aquarium trade. In Hong Kong they sell for $550 per pound, and the illegal trade is so lucrative that smuggled stashes worth many thousands of dollars on the black market are discovered regularly.
The male brooding that is a unique characteristic of seahorses means that the young depend on parental survival for far longer than in most fish. They are mainly monogamous, at least during a season, and widowed animals don’t reproduce until they find a new partner. Their low population density means that lost partners are not quickly replaced. Seahorses are poor swimmers. Low adult mobility and small home ranges restrict recolonization of depleted areas.
Seahorses comprise one genus (Hippocampus) of the family Syngnathidae, which means “fused jaw”. Pipefish and seahorses diverged during the Late Oligocene. Hippos means “horse” and Campus means “sea-monster.”
Seahorses’ unique characteristics include a horse-like head, independently moving eyes, like a chameleon; a brood pouch, called a marsupium, in which the male nourishes the developing young. With their ability to change colour they are masters of camouflage and have filaments that they can grow and reabsorb that help them to blend into the background. Seahorses have no scales, but bony plates under the skin. The prehensile tail is made up of bony plates that can slide across each other to withstand the crushing force of a bird or turtle beak. This amazing design of nature is now being studied for use in body armour and robotics. In fact, the only similarity to other fish is having gills and fins (which oscillate at 35 to 70 beats per second!).
There are 54 recognised species of seahorses within the genus Hippocampus, mostly in tropical seas. In Europe we have only two species: Hippocampus hippocampus and Hippocampus guttulatus. They are classified as “Near Threatened” on the Mediterranean Red List.
Breeding
Breeding is controlled by several factors, the most obvious being the availability of a mate. Some of the females in the Kenna Eco Diving Seahorse Project study area seem to lack a mate and, due to the monogamy of seahorses, are unlikely to find one. Lone females have been seen to travel a hundred square meters, over the course of a week, in search of a mate.
Males have a home range of just a few square meters and mated females have a larger, overlapping territory.
Seahorses perform a daily greeting ritual that reinforces the pair bond.
The number of hours of daylight controls female egg production and male incubation period, with seawater temperature having a reinforcing effect. Seahorse eggs are 5 times bigger and 10 times heavier than other marine fish eggs.
Captive breeding success
Following a decade of research in Spain and Portugal, the European Spiny seahorse is now being bred in captivity with a 90% survival rate. This is a much higher survival rate than in the wild, and aquarium specimens should now all be captive bred.
However, they cannot be released to repopulate the sea until habitat destruction and illegal fishing is prevented. Seahorses are naturally predated upon by Octopus, Scorpionfish, Turtles and Sea birds. But the greatest predator is man!
Seahorse fry spend their first few weeks as part of the plankton, where they are eaten by pelagic species, until the survivors settle into the safety of the seagrass. Less than 1% live to reach adulthood.
Feeding
The horses head shape evolved for pivot feeding to give greater reach and eliminate wake to catch their tiny but very quick copepod prey unawares. Seahorses have a 1 millisecond strike and a 90% catch rate. The independent eyes allow them to focus on prey whilst also keeping an eye out for predators. Food is sucked in through the snout. They have no teeth or stomach, so food has to be easily digestible. Adults eat 70 copepods (Mysis shrimp) per day. Seahorse fry eat thousands during their pelagic stage.
Kenna Eco Diving Seahorse Project
This project is studying the two European species of seahorses that live in the Mediterranean Sea: Hippocampus hippocampus and Hippocampus guttulatus.
Field research is challenging due to several issues. Seahorses are very hard to spot due to their amazing camouflaging abilities. Finding sparse populations is very difficult. In fact, I spent 15 years searching before finding a pair by accident!
They are shy and easily stressed. Therefore excellent buoyancy control is required to avoid disturbing them. Volunteers with Kenna Eco Diving practice buoyancy exercises before being allowed to visit “Seahorse City”, the nickname given to our study area.
In order to identify and monitor individuals we take macro photos using only ambient light. This is because seahorses are especially sensitive to light. They carry dormant diseases that can take hold if they become stressed. We have to gather data without disturbing them.
During our 2014 research season 28 individuals were catalogued, each with ID photographs and a fitting name. Mr Itchy was christened because of his use of his tail in a strange scratching behaviour*. It was suspected that he was suffering from one of the skin diseases that can cause a rapid death. Fortunately the behaviour ceased after several weeks and he was still around at the end of summer before the group moved off to over-winter deeper in the shelter of the Posidonia oceanica seagrass meadow.
Meet Mr Itchy in this video:
[youtube id=”lqITwF3yYBI” width=”100%” height=”400px”]
Marine Life & Conservation
Paul Watson Released as Denmark Blocks Japan’s Extradition Bid
Renowned anti-whaling activist Paul Watson has been released from custody in Greenland after spending five months in detention. Denmark’s Justice Ministry rejected Japan’s request for his extradition, citing insufficient guarantees that his time already served in custody would be credited against any potential sentence.
The 74-year-old Canadian-American was arrested on July 21 in Nuuk, Greenland’s capital, when his ship docked to refuel. His arrest was based on a 2012 Japanese warrant related to a 2010 encounter in Antarctic waters. Japan alleged Watson obstructed operations and caused damage to a whaling research ship during efforts to disrupt illegal whaling. Watson has consistently denied these claims, maintaining his commitment to marine conservation.
Denmark, which oversees extradition matters for Greenland, concluded that while the legal conditions for extradition were met, the lack of assurances from Japan regarding time-served credit made extradition untenable.
In a video shared by his foundation, Watson expressed gratitude and relief, saying, “After five months, it’s good to be out… and good to know they’re not sending me to Japan.” He added that the most difficult part of his time in custody was being separated from his two young sons.
Watson is a pioneering figure in marine conservation, known for founding the Captain Paul Watson Foundation in 2022 after decades of activism with the Sea Shepherd Conservation Society. His bold efforts to defend marine life have earned him widespread support, including from celebrities and conservationists. His work has also been featured in the acclaimed reality TV series Whale Wars.
Watson’s lawyer, Jonas Christoffersen, praised the decision, stating, “We are happy and relieved that Paul Watson is now free.” He added that Watson is eager to reunite with his family and continue his vital work.
The arrest occurred while Watson’s vessel, the M/Y John Paul DeJoria, was en route to the North Pacific with a team of 26 volunteers to intercept a Japanese whaling ship. His foundation described the arrest as politically motivated and emphasized that Watson’s actions were focused on ending illegal whaling practices.
Japan resumed commercial whaling in 2019 after leaving the International Whaling Commission, asserting that whale meat is a cultural tradition. Conservationists, however, continue to challenge these practices, highlighting their impact on marine ecosystems.
Despite the challenges, Watson remains steadfast in his mission to protect marine life and bring attention to whaling practices. His dedication to ocean conservation has made him a globally respected advocate for the environment.
Marine Life & Conservation
12 Days of Zero-Waste Fish-mas
This holiday period, the Marine Conservation Society, the UK’s leading ocean membership charity, invites you to make some simple changes to eating fish this Christmas to help our seas.
Dr Kenneth Bodles, Head of Fisheries and Aquaculture at the Marine Conservation Society, said, “During the festive season, our consumption increases, but so does waste. Sustainability isn’t just about where food comes from – it’s also about how you use it. By reducing waste and making the most out of your seafood, you’re not only taking steps to be more ocean-friendly, but can also help to cut costs during what is often one of the most expensive times of the year”.
The Marine Conservation Society has compiled twelve tips on how to consume seafood sustainably with zero-waste this Christmas:
Buy whole fish instead of fillets
Instead of fillets, consider buying whole fish such as salmon, hake, or lemon sole. By adopting a “nose to tail” approach with cooking, whole-baked fish not only feeds a crowd, but also helps to minimise waste and maximise sustainability by using up every part of the animal, including bones, skin, and fat.
Make fish stock
Leftover fish bones or shells can be put to good use by boiling them to make a nourishing fish stock or bisque. This can be frozen and preserved for later use and makes for a flavourful base in a soup.
Make your own fish pâté
Avoid waste by turning leftover fish, such as smoked mackerel or salmon, into a delicious pâté by blending with cream cheese and lemon. Perfect when paired with crackers.
The sustainability of salmon and mackerel varies depending on where and how it is caught or farmed. For more information on green-rated options, check the charity’s Good Fish Guide.
Buy frozen
By purchasing seafood that is frozen or vacuum-packed, this helps to reduce waste by extending the shelf life of your food.
Fish pie
If you’re wondering what to do with leftover cooked fish, why not opt for a classic fish pie with mashed potatoes, leeks, and a cheesy sauce? A sure crowd pleaser on Boxing Day.
Use the head
Don’t forget the fish head! The meat is incredibly tender and flavourful. The charity recommends a cod’s head curry or recreating Fallow’s renowned cod’s head in siracha butter.
By stretching your ingredients further, not only is this a more sustainable way to enjoy seafood, but also cost-effective by repurposing leftovers and cooking creatively.
Boxing Day brunch
Mix leftover kippers or smoked salmon with scrambled eggs for a tasty, zero-waste, Boxing Day brunch.
For best choice, make sure you buy kippers, or herring, from the North Sea and the North Irish Sea.
Zero-waste storage
A top tip from the Marine Conservation Society to avoid waste is freezing fish offcuts to save for future use.
Crisp up the skin
Even leftover fish skin can be turned into a quick savoury snack by crisping it up in an air fryer with a little olive oil and salt.
Anchovies two ways
Leftover anchovies can either be blended with butter to make a delicious anchovy butter or tossed into pasta for a hit of umami flavour.
The charity recommends opting for anchovies caught in the Bay of Biscay for best choice.
Fishcakes
For an easy, zero-waste meal, leftover seafood trimmings can be mixed with mash and fried in breadcrumbs to make fishcakes.
Pickled mussels
Try pickling mussels in 1:1 vinegar and water, with a dash of sugar for a sustainable, zero-waste snack that can be enjoyed well beyond the festive season.
Mussels farmed in the UK are a seafood superhero. Grown using low-impact methods and harvested by hand, they get all the food they need from the sea around them. This makes them one of the most sustainable, ocean-friendly, and cost-effective seafood options.
Players of People’s Postcode Lottery have raised £6.6M towards the Marine Conservation Society’s vital work in making seafood more sustainable.
Laura Chow, Head of Charities at People’s Postcode Lottery, said: “Fish is a festive favourite for many, but making sustainable choices when it comes to how we buy and eat seafood makes all the difference for our ocean. Support from players of People’s Postcode Lottery has helped the Marine Conservation Society further its sustainable seafood work, so that we can all enjoy healthier, better protected seas.”
The Marine Conservation Society encourages you to make sustainable seafood choices a year-round habit, not just for Christmas. To check how sustainable the seafood on your plate is, you can visit the charity’s Good Fish Guide. The Guide helps consumers and businesses identify the most sustainable seafood using a simple traffic light system, based on where and how species are caught or farmed. Green is the best choice, amber means improvements are needed, and red indicates fish to avoid buying.
Zero-waste gift idea
Why not embrace a zero-waste Christmas by gifting a membership to support marine conservation? It’s a meaningful, low-waste gift that helps protect our ocean for generations to come. Memberships start from as little as £5 a month – the price of a sandwich and drink from your local coffee shop.
Find the latest sustainable seafood advice for wild-caught and farmed seafood on the Good Fish Guide, downloadable to your phone from www.mcsuk.org/goodfishguide.
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