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Lighted Nets Protect Marine Wildlife | Earth Wise

March 16, 2022 By EarthWise Leave a Comment

Gillnets are walls or curtains of netting that hang in the water to trap fish. They are one of the most extensively used fishing gear in coastal regions throughout the world’s oceans. While they are very effective at catching targeted fish species, they are not discriminating. As a result, they carry significant risk of bycatch – the accidental capture of unwanted species as well as other interactions with various marine animals.

Researchers from The Wildlife Conservation Society, NOAA Fisheries, Arizona State University, and the National Fisheries and Aquaculture Institute of Mexico have recently published a study showing that using lighted gillnets reduced overall bycatch by 63%, including a 95% reduction in sharks, skates, and rays, and an 81% reduction in Humboldt squid.

Gillnets often catch endangered, threatened, and protected species such as sharks, sea turtles, marine mammals, and seabirds, as well as unwanted species and non-marketable juvenile target fish species. The bycatch animals are often dead or injured and are generally dumped overboard.

Illuminating gillnets with LED lights has emerged over the past decade as an effective tool to reduce bycatch of endangered sea turtles. The new study is the first detailed examination of the effectiveness of illumination for other vulnerable species.

Gillnets are ubiquitous because they are inexpensive and catch everything that passes them. Global populations of sharks, skates, and rays have declined as a result of bycatch and illegal fishing. The results of this study are encouraging because they provide a practical solution for increasing the selectivity of gillnets and avoiding bycatch.

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Lighted Nets Dramatically Reduce Bycatch of Sharks and Other Wildlife While Making Fishing More Efficient

Photo, posted September 19, 2015, courtesy of Jim Bahn via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Saving The Queen Conch | Earth Wise

February 3, 2021 By EarthWise Leave a Comment

Queen conchs are large sea snails belonging to the same taxonomic group as clams, oysters, and squid. They live on coral reefs or seagrass meadows in warm, shallow waters. Queen conchs are found throughout the Caribbean Sea and Gulf of Mexico, ranging as far north as Bermuda and as far south as Brazil.

Reaching up to 12” long and living up to 40 years, the queen conch is prized as a delicacy and revered for its shell. It’s the second most important sea-bottom fishery in the Caribbean region, trailing only the spiny lobster.

But queen conchs face a challenge. Their populations are in a steady rate of decline as a result of overfishing, habitat degradation, and hurricane damage. In some places, the numbers are so low that remaining conchs cannot find breeding partners. The situation is urgent from both an ecological and economical perspective.

As a result, Megan Davis, a scientist from Florida Atlantic University who spent more than four decades researching queen conch, has released an 80-page, step-by-step user manual about how to care for the species. Her work was recently published in the National Shellfisheries Association’s Journal of Shellfish Research.

According to Davis, aquaculture, along with conservation of breeding populations and fishery management, are ways to help ensure longevity of the queen conch. With requests for mariculture guidance pouring in from communities throughout the Caribbean, Davis and her collaborators are expanding their queen conch conservation, education, and restorative mariculture program.

Their desired outcomes include creating protected breeding areas, establishing sustainable hatcheries, and repopulating protected habitats.

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‘Hail to the queen’: Saving the Caribbean queen conch

Photo, posted June 3, 2012, courtesy of Christopher Gonzalez via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Finding Plastic In Seafood | Earth Wise

September 15, 2020 By EarthWise Leave a Comment

Researchers from the University of Exeter in the UK and the University of Queensland in Australia have developed a new method for identifying and measuring the presence of five different types of plastic in seafood.

The researchers purchased oysters, prawns, squid, crabs, and sardines from a market in Australia and analyzed them using the new technique. They found plastic in every single sample.

Their findings showed that the amount of plastics present varies greatly among species and differs between individuals of the same species. The measured plastic levels were 0.04 mg per gram of seafood in squid, 0.07 mg in prawns, 0.1 mg in oysters, 0.3 mg in crabs, and 2.9 mg in sardines.

All the plastics are types commonly used in plastic packaging and synthetic textiles and are increasingly found in marine litter: polystyrene, polyethylene, polyvinyl chloride, polypropylene, and polymethyl methacrylate.

The new method treats the seafood tissues with chemicals that dissolve the plastics present within them. The resulting solution is then analyzed using a highly sensitive technique called Pyrolysis Gas Chromatography Mass Spectrometry which both identifies and quantifies the plastics.

Microplastics are an increasing source of pollution for much of the planet, including the oceans where they are eaten by all types of marine creatures ranging from planktonic organisms to large mammals. Microplastics enter our diet not only from seafood, but also from bottled water, sea salt, beer, and honey, as well as from dust that settles on our food.

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Seafood study finds plastic in all samples

Photo, posted June 23, 2007, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Squid Skin Blanket

June 25, 2019 By EarthWise Leave a Comment

Ultra-lightweight space blankets have been around for a long time. Marathon runners wrap themselves in them to avoid losing body heat after a race. They are very effective, but the amount of heat that they trap is fixed. There is no way to regulate how much heat is trapped or released using a space blanket.

Researchers at the University of California, Irvine have developed a next-generation, adaptive space blanket that allows users to control their temperature. The inspiration for the design was the skins of various species of squids, octopi and cuttlefish. The ability of these aquatic creatures to camouflage themselves by rapidly changing color is due, in part, to skin cells called chromatophores that can instantly change from tiny points to flattened disks.

The Irvine researchers have developed a material that contains a layer of tiny metal islands that border each other. In the relaxed state, the islands are bunched together, and the material reflects and traps heat, much like a conventional Mylar space blanket. But when the material is stretched, the islands spread apart, which allows infrared radiation to go through and heat to escape.

The researchers envision many other applications for the novel material, including adaptable insulation for buildings and tents that can be adapted to different weather conditions. There is even the possibility of clothing that can be adjusted to suit the comfort of each person.

The new material is lightweight, easy and inexpensive to manufacture, and is durable. It can be stretched and returned to its original state thousands of times. Some day we might all be wrapping ourselves in imitation squid skins.

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Squid skin inspires creation of next-generation space blanket

Photo, posted May 29, 2005, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.