New research reveals 12 ways aquaculture can benefit the environment

Researchers have identified 12 potential ecological benefits of aquaculture including species recovery, habitat restoration, rehabilitation and protection, and removal of overabundant species.
Photo Credit: John French

Aquaculture, or the farming of aquatic plants and animals, contributes to biodiversity and habitat loss in freshwater and marine ecosystems globally, but when used wisely, it can also be part of the solution, new research shows.

Published today in Conservation Biology, University of Melbourne researchers have identified 12 potential ecological benefits of aquaculture. These include species recovery, habitat restoration, rehabilitation and protection, and removal of overabundant species.

Lead author, University of Melbourne researcher Ms. Kathy Overton, said the potential environmental benefits of aquaculture have gone under the radar for many years.

“Most people around the world live near freshwater or marine ecosystems, and we rely on them as sources of food, tourism, recreation, culture, and livelihood,” Ms. Overton said.

“However, our impacts on freshwater and marine ecosystems are degrading important habitats and causing rapid declines in biodiversity. While the negative impacts of some types of aquacultures are well known, we can also use aquaculture as a tool to slow or stop these negative impacts and help restore ecosystems that have been largely lost over the last century.”

Marine reserves unlikely to restore marine ecosystems

The study used visual censuses and the analysis of stable isotopes to determine the abundance and trophic niche of carnivorous fish in marine reserves and areas open to fishing.
Photo Credit: Lluís Cardona

Protected marine areas are one of the essential tools for the conservation of natural resources affected by human impact —mainly fishing—, but are they enough to recover the functioning of these systems? A study published in the ICES Journal of Marine Science, led by researchers from the Biodiversity Research Institute (IRBio) of the University of Barcelona, in collaboration with researchers from the Group of Ecosystem Oceanography (GRECO) of the Oceanographic Center of the Balearic Islands, highlights the limitations of marine reserves in restoring food webs to their pristine state prior to the impact of intensive fishing.

Protected marine areas are one of the essential tools for the conservation of natural resources affected by human impact —mainly fishing—, but are they enough to recover the functioning of these systems? A study published in the ICES Journal of Marine Science, led by researchers from the Biodiversity Research Institute (IRBio) of the University of Barcelona, in collaboration with researchers from the Group of Ecosystem Oceanography (GRECO) of the Oceanographic Center of the Balearic Islands, highlights the limitations of marine reserves in restoring food webs to their pristine state prior to the impact of intensive fishing.

Algae bio hacks itself in adapting to climate change

Phytoplankton - the foundation of the oceanic food chain.
Photo Credit: NOAA

Clear evidence that marine phytoplankton are much more resilient to future climate change than previously thought is the focus of a study published in Science Advances by an international team of scientists, including University of Hawaiʻi at Mānoa oceanography professor David Karl.

“Knowing how marine algae will respond to global warming and to associated decline of nutrients in upper ocean waters is crucial for understanding the long-term habitability of our planet,” said Karl.

Combining data from the long-term Hawaiʻi Ocean Time-series program at UH Mānoa with new climate model simulations conducted on one of South Korea’s fastest supercomputers, the scientists revealed that a mechanism, known as nutrient uptake plasticity, allows marine algae to adapt and cope with nutrient-poor ocean conditions that are expected to occur over the next decades in response to global warming of the upper ocean.

Short-term bang of fireworks has long-term impact on wildlife

Photo Credit: Jill Wellington

Popular fireworks should be replaced with cleaner drone and laser light shows to avoid the “highly damaging” impact on wildlife, domestic pets and the broader environment, new Curtin-led research has found.

The new research, published in Pacific Conservation Biology, examined the environmental toll of firework displays by reviewing the ecological effects of Diwali festivities in India, Fourth of July celebrations across the United States of America, and other events in New Zealand and parts of Europe.

Examples included fireworks in Spanish festivals impacting the breeding success of House Sparrows, July firework displays being implicated in the decline of Brandt’s Cormorant colonies in California, and South American sea lions changing their behavior during breeding season as a result of New Year’s fireworks in Chile.

Lead author Associate Professor Bill Bateman, from Curtin’s School of Molecular and Life Sciences, said fireworks remained globally popular despite the overwhelming evidence that they negatively impacted wildlife, domestic animals and the environment.

New virus discovered in whales, dolphins across the Pacific

Photo Credit: Richard Sagredo

A novel virus, potentially fatal to whales and dolphins, has been discovered by researchers at the University of Hawaiʻi Health and Stranding Lab. Prior to its discovery in 10 whale and dolphin host species across the Pacific, the virus was found in only a single marine mammal worldwide, a Longman’s beaked whale stranded on Maui in 2010. The findings were published in Frontiers in Marine Science.

The discovery of beaked whale circovirus (BWCV) in whales and dolphins expands the knowledge of marine mammal species that can become infected with the disease. Circoviruses are DNA viruses that cause disease in birds, pigs and dogs, and in severe cases can become fatal.

“Our study found Cuvier’s beaked whales tested positive for BWCV in Saipan and American Samoa, nearly 4,000 miles away from the first discovered case,” said Kristi West, director of the UH Health and Stranding Lab. “The positive cases found outside of Hawaiʻi were surprising, and indicates that this virus is spread across the Central and Western Pacific and may have a global presence in marine mammals.”

Reef fish must relearn 'rules of engagement' after coral bleaching

butterfly fish
Photo Credit: Светлана

Mass coral bleaching events are making it harder for some species of reef fish to identify competitors, new research reveals.

Scientists studying reefs across five Indo-Pacific regions found that the ability of butterfly fish individuals to identify competitor species and respond appropriately was compromised after widespread loss of coral caused by bleaching.

This change means they make poorer decisions that leave them less able to avoid unnecessary fights, using up precious limited energy. The scientists behind the study believe these changes could have implications for species survival as further global warming increases the likelihood of coral loss.

“By recognizing a competitor, individual fish can make decisions about whether to escalate, or retreat from, a contest—conserving valuable energy and avoiding injuries,” said Sally Keith, a senior lecturer in marine biology at Lancaster University and lead author of the study.

Major Breakthrough as Scientists Sequence the Genomes of Endangered Sharks

Hammerhead Shark
Photo Credit: David Clode

The first-ever chromosome-level genome sequences completed for great hammerhead and shortfin mako sharks have shown that both species have experienced major population declines over a 250,000-year history. Low genetic diversity and signs of inbreeding add a layer of concern to the management of Critically Endangered great hammerhead sharks, whose populations have been in freefall recently due to overfishing for their highly valued fins. In contrast, with a larger effective population size (the ideal breeding population size) in the past and higher genetic diversity, shortfin mako sharks appear equipped to be more resilient to rapid environmental change: that is, if the current fishing pressure on them is substantially reduced.

“With their whole genomes deciphered at high resolution we have a much better window into the evolutionary history of these endangered species,” said Mahmood Shivji, Ph.D., professor at Nova Southeastern University’s (NSU) Halmos College of Arts and Sciences and director of the Save Our Seas Foundation Shark Research Center and NSU’s Guy Harvey Research Institute.

It’s a startling image that describes a milestone in conservation science for sharks. Shivji, Michael Stanhope, Ph.D., from Cornell University’s College of Veterinary Medicine and their collaborators have glanced back in history by sequencing to chromosome level the genomes (entire genetic blueprint) of great hammerhead and shortfin mako sharks. Their DNA timeline shows that their populations have declined substantially over 250,000 years. What the scientists have also found is worrying: great hammerhead sharks have low genetic variation, which makes them less resilient to adapting to our rapidly changing world. The species also shows signs of inbreeding, an issue that can lower the ability of its populations to survive.

Rosenstiel marine researcher identifies new Bottlenose dolphin subspecies

New subspecies, called the Eastern Tropical Pacific bottlenose dolphin (Tursiops truncatus nuuanu), is smaller than other common bottlenose dolphins.   
Photo Credit: NOAA/NMFS/SWFSC.

A marine researcher at the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science has identified a new bottlenose dolphin subspecies found only in the eastern tropical Pacific Ocean. “While there is a common belief that all dolphin species are already known, improvements in technologies and methodologies are helping to reveal a greater biodiversity in more recent years,” said Ana Costa, Ph.D., a Rosenstiel lecturer specializing in marine mammalogy.

After examining and analyzing a series of specimens, Costa and collaborators of the National Oceanic and Atmospheric Administration, found that the new subspecies, called the Eastern Tropical Pacific bottlenose dolphin (Tursiops truncatus nuuanu), is smaller than other common bottlenose dolphins. These dolphins likely prefer deep offshore waters between southern Baja California and the Galapagos Islands, she added.

3D imaging of shark embryos reveals evolution of pelvic fins

Photo Credit: Marcelo Cidrack

Curtin University researchers have revealed how the pelvic fins of fish such as sharks and chimaeras have evolved from their sudden appearance in the fossil record over 410 million years ago.

The team used CT scanning and 3D modelling to study the growth of pelvic fins in fish embryos to help us understand how the skeleton of these fins changed over evolutionary history.

Lead author and PhD candidate Jacob Pears from Curtin’s School of Molecular and Life Sciences said the research showed what the development of modern animals can tell us about their evolution.

“Our work focused on cartilaginous fish and in particular looked at the pelvic fins of elephant sharks. The fine detail from our imaging revealed the basipterygium (pelvic fin bar), which like the femur and tibia in humans, were formed by the fusion of fin radials during early embryonic development,” Mr. Pears said.

New Study Sheds Light on Boric Acid Transport and Excretion in Marine Fish

Seawater is known to contain a significant concentration of boric acid, which can be toxic and deadly to living systems. As such, fish living in marine habitats need to be able to excrete boric acid in order to maintain a healthy boron balance. Tokyo Tech researchers have now identified the gene and mechanism of boric acid transport in seawater fish and contrasted it to freshwater species.

Marine fishes live in highly saline environments with ionic concentrations that are vastly different from their blood plasma. Seawater contains a variety of toxic ion species that can build up in the body if the fish does not excrete them. One example of this is boric acid, which—in small amounts—is a vital micronutrient for animals but can prove toxic in excess. Hence, marine fish must develop physiologic means to excrete boric acid. However, how they do this is, as yet, unknown. Now, an international team led by researchers from Tokyo Institute of Technology (Tokyo Tech) has unveiled and demonstrated the molecular mechanisms underlying boric acid secretion in marine pufferfish.

Associate Professor Akira Kato of Tokyo Tech is the principal author of the study, which was published in the Journal of Biological Chemistry. He tells us more about it. "We compared euryhaline pufferfish (which are pufferfish that can survive in varying levels of salinity) accustomed to saltwater, brackish water, and freshwater. On comparing fish from these three habitats, we found that the urine of a seawater pufferfish (Takifugu pufferfish) contained 300 times more boric acid than pufferfish blood, and 60 times more boric acid than seawater." The urine of freshwater fish contained almost 1000 times less boric acid than that of seawater pufferfish. These findings established that Takifugu pufferfish living in seawater excrete boric acid in their urine. Just like in humans, the process of excretion via urine in pufferfish is mediated by the kidneys.

All West Coast Abalones at Risk of Extinction on the IUCN Red List

A red abalone is surrounded by a barren of purple sea urchins.
Photo Credit: Katie Sowul/California Department of Fish and Wildlife

All seven of the United States’ abalone species that live on the West Coast are now listed as Critically Endangered or Endangered on the International Union for Conservation of Nature, or IUCN, Red List of Threatened Species. These listings were based on a West Coast abalones assessment led by Laura-Rogers Bennett of the California Department of Fish and Wildlife, or CDFW, and University of California, Davis.

Six species — red, white, black, green, pink and flat abalone — are listed by IUCN as critically endangered. The northern abalone, also known as threaded or pinto abalone, is listed as endangered.

The IUCN Red List is considered the world’s most comprehensive inventory of the global conservation status of species. While the listing does not carry a legal requirement to aid imperiled species, it helps guide and inform global conservation and funding priorities.

Hibernating Corals and the Microbiomes That Sustain Them

A microscope image of Northern star coral with its polyps extended.
Photo Credit: Alicia Schickle, Roger Williams University

As winter approaches, many species of animals — from bears and squirrels to parasitic wasps and a few lucky humans — hunker down for some needed rest. The northern star coral (Astrangia poculata) also enters a hibernating state of dormancy, or quiescence, during this time. But what happens to its microbiome while it’s sleeping?

A study led by University of California, Davis, Assistant Professor Anya Brown found that microbial communities shift while this coral enters dormancy, providing it an important seasonal reset. The work may carry implications for coral in warmer waters struggling with climate change and other environmental issues.

“Dormancy, at its most basic, is a response to an environmental stressor — in this case, cold stress,” said Brown, who is part of the UC Davis Bodega Marine Laboratory in the Department of Evolution and Ecology. “If we understand more about this recovery period, it might help us understand what microbes may be responsible for recovering coral in warmer tropical systems.”

Synthetic fibers discovered in Antarctic samples show the ‘pristine’ continent is now a sink for plastic pollution

As nations prepare to meet in Uruguay to negotiate a new Global Plastics Treaty, a new study has revealed the discovery of synthetic plastic fibers in air, seawater, sediment and sea ice sampled in the Antarctic Weddell Sea. The field research was carried out by scientists from the University of Oxford and Nekton (a not-for-profit research institute) during an expedition to discover Sir Ernest Shackleton’s ship, the Endurance. The results are published in the journal Frontiers in Marine Science.

Fibrous polyesters, primarily from textiles, were found in all samples. The majority of microplastic fibers identified were found in the Antarctic air samples, revealing that Antarctic animals and seabirds could be breathing them.

‘The issue of microplastic fibers is also an airborne problem reaching even the last remaining pristine environments on our planet’, stated co-author Lucy Woodall, a Professor in the University of Oxford’s Department of Biology and Principal Scientist at Nekton. ‘Synthetic fibers are the most prevalent form of microplastic pollution globally and tackling this issue must be at the heart of the Plastic Treaty negotiations.’ Professor Woodall was the first to reveal the prevalence of plastic in the deep sea in 2014.

Disease-Resistant Corals Can Help ‘Rescue’ Vulnerable Ones

UC Davis Assistant Professor Anya Brown dives in a coral reef in Little Cayman as part of a research study.
Photo Credit: Julie Meyer/University of Florida

Under the right living arrangement, disease-resistant corals can help “rescue” corals that are more vulnerable to disease, found a study from the University of California, Davis, that monitored a disease outbreak at a coral nursery in Little Cayman, Cayman Islands.

The study, published in the journal Scientific Reports, found that when people grow corals of the same genotype — or genetic makeup — together, those corals are more vulnerable to disease than corals that grow among a mixture of genotypes. The study further found that some vulnerable corals can be “rescued” by resistant genotypes.

“We saw that some corals were more resistant to disease just by being around other corals that were particularly resistant,” said lead author Anya Brown, an assistant professor at the UC Davis Bodega Marine Laboratory in the Department of Evolution and Ecology. “Proximity to these resistant genotypes helped buffer the susceptible corals from the effects of the disease.”

The findings provide further evidence that genetic diversity can help reduce disease transmission among corals, while also showing that it’s important to consider how corals are arranged in nurseries and reef restoration projects to prevent the spread of disease.

What Darwin would discover today

Filmmaker Victor Rault set sail from Plymouth on the Captain Darwin in 2021, following in the footsteps of Darwin's HMS Beagle. He wants to explore how the ecosystem has changed since Darwin's voyage in 1832.
Photo Credit: Victor Rault / Captain Darwin 

"If Charles Darwin had had the opportunity to dive off the Cape Verde Islands, he would have been completely thrilled", Eduardo Sampaio is convinced, because Darwin would have seen a fascinating, species-rich landscape. But he lacked diving equipment. Thus, in his notes The Voyage of the Beagle, Darwin described Cape Verde as a barren landscape.

Eduardo Sampaio, affiliate member of the Cluster of Excellence "Centre for the Advanced Study of Collective Behavior" (CASCB) at the University of Konstanz, had quite the opposite experience. He was invited on board the ship Captain Darwin by filmmaker Victor Rault to continue his octopus research.

Victor Rault, 30, set sail from Plymouth on the Captain Darwin in 2021, following in the footsteps of Darwin's HMS Beagle. He wants to explore how the ecosystem has changed since Darwin's voyage on the HMS Beagle in 1832. Researchers and citizens have been invited to travel along and conduct experiments in the spirit of Darwin. "When Victor told me about his project, I was baffled", recalls biologist Eduardo Sampaio from Portugal. He says: "It was immediately clear to me that it's an excellent idea to retrace the path of Charles Darwin. I was more than keen to jump on board!"

Disease carried by cats, pigs kill 2 spinner dolphins in Hawaiian waters

Photo Credit: Flavio Gasperini

Two spinner dolphins died from toxoplasmosis after becoming infected with the parasite Toxoplasma gondii, according to researchers at the University of Hawaiʻi at Mānoa Health and Stranding Lab. One dolphin was stranded on Hawaiʻi Island in 2015 and the other on Oʻahu in 2019.

Invasive species such as pigs, mongoose, chickens and cats harbor the parasite, but it is unclear which genotypes are most likely to infect wildlife species. The findings were published in Diseases of Aquatic Organisms.

UH researchers screened archived tissues from past dolphin and whale strandings and did not find the parasite in any animals except those that died of it. This demonstrates that if a spinner dolphin has a severe toxoplasmosis infection they will die.

“We suspect that many more spinner dolphins may succumb to toxoplasmosis and die than the animals that are recovered dead and examined for cause of death,” said Kristi West, associate researcher at UH Mānoa’s Hawaiʻi Institute of Marine Biology who directs the UH Health and Stranding Lab. “A better understanding of toxoplasmosis infections and infectious cycles is important to developing effective conservation strategies for protected and endangered Hawaiian wildlife.”

New critical period of sex determination in sea turtles identified

Sea turtles’ sex is determined based on the environment, which makes them especially vulnerable to climate change. An increase in incubation temperatures could jeopardize the production of both sexes.
 Photo credit: Jay Paredes

Unlike humans, turtles, lizards and other reptiles – such as crocodiles – do not have sex chromosomes. Their sex is determined based on the environment, which makes them especially vulnerable to climate change. An increase in incubation temperatures could jeopardize the production of both sexes.

Gauging primary sex ratios in these species is critical because it assesses their vulnerability under both current and future climate change constraints. While there has been great progress in sex ratio prediction, studies have been hampered due to a lack of accurate and representative regional and population sex ratio estimates. As a result, primary sex ratios calculations could be skewed.

Researchers from Florida Atlantic University, in collaboration with the Université Paris-Saclay in France, have demonstrated that the timing of key developmental process driven by temperature is vital when it comes to identifying when sex is determined for sea turtle embryos. They also are the first to compare the output of the most widely used sex ratio prediction methods to actual sex ratios from natural clutches in sea turtles.

They have developed a new way to integrate the effect of thermal fluctuations on embryonic sex determination and predict sex ratios with much better accuracy than prior models. This method measures the strength of masculinization or feminization of temperatures using novel parameters that have uncovered how temperature-sensitive sex determination works.

California Academy of Sciences researchers produce first-ever ‘family tree’ for aquarium-bred corals

Two-year-old corals sampled for this study in the Academy's Coral Spawning Lab.
Photo Credit: California Academy of Sciences

Corals bred in public aquaria provide novel research opportunities and a healthy stock for outplanting into the wild, essential components of a thriving future for coral reef ecosystems, which support around 25% of all life in Earth’s oceans. But the long-term success of such efforts hinges in part on maintaining genetic diversity in aquarium-bred corals which leads to increased resilience to threats like ocean warming and acidification. In a study published today in Frontiers in Marine Science, a diverse team of Steinhart Aquarium biologists and researchers from the California Academy of Sciences' Coral Spawning Lab produce the first-ever pedigree, or ‘family tree’, for corals bred in an aquarium and provide a list of best practices to maintain genetic diversity in aquarium-bred corals.

“Genetic diversity is what enables species to adapt to the myriad threats resulting from climate change,” says Academy Curator Rebecca Albright, PhD, who founded the Coral Spawning Lab, one of only a handful of facilities on Earth capable of successfully breeding corals. Albright’s work is an integral part of the Academy’s Hope for Reefs initiative, which is aimed at halting the decline of coral reefs in this generation. “For facilities like ours at the Coral Spawning Lab, ensuring each generation of corals is diverse allows us to conduct more robust experiments, which is a critical element of better understanding how corals can thrive on our changing planet. For organizations that do outplantings, increased genetic diversity translates to a greater chance of survival in the wild.”

Surfing scientists conduct 3D reef research at epic surf break

MEGA Lab Research Technician Kailey Pascoe mapping Cloudbreak in Fiji
Resized Image using AI by SFLORG
Credit: Source University of Hawaiʻi

With more than 80% of the world’s oceans left unexplored, untouched and unseen by humans, researchers know more about the surface of Mars than the ocean. A University of Hawaiʻi at Hilo professor is helping to fill that knowledge gap by leading a team of scientists to 3D map the planet’s premier surf breaks to help better protect reefs around the world.

Professors John H.R. Burns (UH Hilo), Haunani Kane (Arizona State University) and Cliff Kapono (Arizona State University) recently mapped the reef at Kurukuru Mailani in Fiji, also known as Cloudbreak, which is home to some of the biggest and best waves in the world. The team takes high resolution images of the reef and uses a technique called photogrammetry to create 3D reconstructions that can be studied to help provide a better understanding of reef systems.

“These models will help us to understand the composition, characteristics and ecology of the reef and these waves that will help us to protect them in the face of disturbances such as sea level rise,” said Burns, an associate professor of marine science.

How much microplastic do whales eat? Up to 10 million pieces per day

Humpback whales lunge feed in Monterey Bay. New research shows whales are ingesting plastic in larger quantities than previously thought, and nearly all comes from their prey, not from the enormous volumes of seawater the whales gulp when feeding.
Photo Credit: shadowfaxone

Analysis of ocean plastic pollution and whale foraging behavior tracked with noninvasive tags shows whales are ingesting tiny specks of plastic in far bigger quantities than previously thought, and nearly all of it comes from the animals they eat – not the water they gulp.

The largest animals ever known to have lived on Earth ingest the tiniest specks of plastic in colossal amounts, Stanford University scientists have found.

Published in Nature Communications, the study focuses on blue, fin, and humpback whales and their consumption of plastic fragments no bigger than a few grains of sand, which are commonly called microplastics. The authors combined measures of microplastic concentrations up and down the water column off the coast of California with detailed logs of where hundreds of whales carrying tracking devices foraged for food between 2010 and 2019.

They found the whales predominantly feed 50 to 250 meters below the surface, a depth that coincides with the highest concentrations of microplastic in the open ocean. The planet’s biggest creature – the blue whale – ingests the most plastic, at an estimated 10 million pieces per day as it feeds almost exclusively on shrimplike animals called krill.

“They’re lower on the food chain than you might expect by their massive size, which puts them closer to where the plastic is in the water. There’s only one link: The krill eats the plastic, and then the whale eats the krill,” said study co-author Matthew Savoca, a postdoctoral scholar at Hopkins Marine Station, Stanford’s marine laboratory on the Monterey Peninsula.