Marine Life & Conservation

New study measures how much of corals’ nutrition comes from hunting

Published

5 years ago

October 7, 2019

When it comes to feeding, corals have a few tricks up their sleeve. Most of their nutrients come from microscopic algae living inside of them, but if those algae aren’t creating enough sustenance, corals can use their tentacles to grab and eat tiny prey swimming nearby.

A new study from researchers at the Woods Hole Oceanographic Institution (WHOI), the University of New Mexico, and Scripps Institution of Oceanography is revealing that more of corals’ nutrients come from this sort of hunting than previously expected, information that may help predict the fate of coral reefs as global ocean temperatures rise. The study published Sept. 17, 2019, in the journal Functional Ecology.

“When you have a heat wave, corals start bleaching. Symbiotic algae, which live inside corals and provide them with most of their nutrients, are expelled from their body. If corals stay bleached for too long they basically starve to death,” says Michael Fox, a postdoctoral scholar at WHOI and lead author on the paper. “But if a coral has the opportunity to eat a lot before it bleaches or while it is bleached, it can survive off its fat stores long enough to regain those symbionts when water temperatures cool off. If we can better understand when, where, or why corals are eating, we may be able to understand why they survive better in some places than others during future bleaching events.”

Corals

Michael Fox, WHOI postdoctoral scholar and lead author of the study, sampling coral on Pulo Anna Island, Palau. Photo courtesy of Brian Zgliczynski

Fox and his colleagues conducted their study from samples they collected at Palmyra Atoll, a remote US national wildlife refuge in the central Pacific Ocean. After bringing them back into the lab, the researchers removed the coral polyps from their skeletons, and then separated the coral animals and their symbiotic algae in a centrifuge. The team then extracted essential amino acids from the corals, their symbionts, and the tiny zooplankton that corals often eat.

“Essential amino acids are required for an animal to survive, but most corals can’t make them. They have to get them from either their symbionts or something they just ate,” says Fox. “But each of those sources make amino acids in different ways, which gives the molecules distinct chemical signatures.”

Those signatures can be used to “fingerprint” the source of the amino acid, he adds. By measuring chemical differences in six individual amino acids, the researchers were able to determine how much of a coral’s nutrition was coming from symbionts, or from captured prey. This new method for measuring coral nutrition allows scientists to estimate the contributions of different food sources to coral diets, providing a more accurate view of their nutrition than previous methods. The technique was co-developed by animal ecologist Seth Newsome of the University of New Mexico, who is also a co-author on the study.

“To my knowledge, this has never been done with corals before. It really changed our perspective,” says Fox. “Our findings suggest that some corals are eating a lot more than we previously thought, which has big implications for reef survival during climate change. We’ve also learned that individual corals of the same species can have very different diets—this may be an important source of variation that we’ll have to take into account to understand how corals will respond to future changes.”

For more information about the work of the WHOI please visit their website by clicking here.

Marine Life & Conservation

Paul Watson Released as Denmark Blocks Japan’s Extradition Bid

Published

2 days ago

December 17, 2024

Team Scubaverse

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

Published

2 weeks ago

December 3, 2024

Team Scubaverse

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.