Saving Seafood

How ‘ghost’ fishing gear affects at-risk species and fisheries’ bottom line

August 5, 2021 — Southwest Nova Scotia is one of Canada’s most productive lobster fishing region, spanning more than 21,000 square kilometers and contributing a significant portion of the country’s lobster supply.

With a busy fishery, though, has come the growing challenge of abandoned, lost and discarded fishing  (ALDFG)—a collection of , ropes, hooks, cables and other fishing-related equipment that drift through the water column or litter the ocean floor. It is a global problem, but one that hasn’t been widely quantified.

Researchers at Dalhousie University wanted to find out how much gear might be in the Southwest Nova Scotia (SWNS) fishing zone and how it might be affecting the existing fishery. Their recently published  provides the first preliminary assessment of environmental and economic impacts of ALDFG on the commercial  industry in the area.

Read the full story at PHYS.org

How Might Fish Farms Be Affecting Lobsters?

July 19, 2021 — Open-net pen Atlantic salmon aquaculture is big business on Canada’s east coast. Given the industry’s size, much has been studied and written about its effects on wild salmon. But how might fish farms be affecting other species in their vicinity—such as lobster? Lobster is one of the most economically valuable wild species, and the bulk of the world’s catch is made along the eastern seaboard of North America. Inka Milewski, who studies the interactions between aquaculture and the wider ecosystem at Dalhousie University in Nova Scotia, recently parsed the scientific literature to determine the ways in which salmon aquaculture is affecting wild lobsters.

Milewski and her colleagues identified a multitude of factors that could affect lobsters, their habitat, and the lobster fishery. Net pens change oceanographic conditions, for example by reducing current speeds, increasing turbulence, and breaking up waves. The farms also generate waste, such as excess food, fish feces, and urine, as well as the chemicals used to control pests and diseases. Lights, noises, and odors associated with the farms can disrupt lobster behavior.

Milewski says she was most surprised by how sensitive lobsters are to the particulate and dissolved organic and inorganic waste that result from fish feces and uneaten food. These chemicals can disrupt critical lobster behaviors like feeding, spawning, and mating. Her review identified studies that show that these waste products can change the quality of lobsters’ diets and promote harmful algal blooms near farms.

“There is a tremendous amount of waste generated by fish farms,” Milewski says. “I don’t think people have a sense of the scale.” A fairly typical farm of about 600,000 fish will generate around 40 tonnes of waste every month during its 22-month production cycle. “It’s understandable how that waste can change lobsters’ behavior, distribution, and abundance,” she adds.

But the review also identified serious gaps in our understanding of the interactions between aquaculture operations and lobsters. While some aspects, such as the use of chemical pesticides, have been well studied, information on others, including waste discharges, disease, and noise, are limited or entirely lacking.

Read the full story at Hakai Magazine

New research reveals surprising differences between salmon species — helping consumers decide which ones to serve for dinner

July 9, 2020 — It is well known that salmon provides a range of valuable nutrients, including omega-3 fatty acids and protein. But it can be confusing for consumers to know which species offers the highest level of nutrition when they are faced with several different types of salmon at the grocery store.

There are also mixed messages when it comes to farmed salmon, with some people believing it may contain contaminants and is not as nutritious as wild-caught fish.

Consumers can’t look to labels for clarity since nutritional information is not required on seafood packaging in Canada and the United States.

Stefanie Colombo, an assistant professor of Aquaculture at Dalhousie University’s Agriculture Campus, wanted to shed some light on the murky area by exploring the nutritional differences between salmon. Her research, published recently in the Journal of Agriculture and Food Research, produced some surprising findings she hopes may dispel misunderstandings about farmed salmon.

“I get a lot of questions from people I meet about farmed salmon and many people have the idea that it’s not good for you, that it’s full of fat and contaminants,” says Dr. Colombo, who also holds the Canada Research Chair in Aquaculture Nutrition. “I knew these were misconceptions, but I wanted to know how it compared to the other types of salmon that were out there.

Read the full story at Dal News

Silence is golden for whales as lockdown reduces ocean noise

April 28, 2020 — In cities, human lockdowns during the coronavirus pandemic have offered some respite to the natural world, with clear skies and the return of wildlife to waterways. Now evidence of a drop in underwater noise pollution has led experts to predict the crisis may also be good news for whales and other sea mammals.

Researchers examining real-time underwater sound signals from seabed observatories run by Ocean Networks Canada near the port of Vancouver found a significant drop in low-frequency sound associated with ships.

David Barclay, assistant professor of oceanography at Dalhousie University, the lead author of a paper reviewing the phenomena, examined sound power – a way of measuring “loudness” – in the 100 Hz range from two sites, one inland and one farther offshore. He found a significant drop in noise from both.

Generally, we know underwater noise at this frequency has effects on marine mammals,” Barclay said.

“There has been a consistent drop in noise since 1 January, which has amounted to a change of four or five decibels in the period up to 1 April,” he said. Economic data from the port showed a drop of around 20% in exports and imports over the same period, he said.

The deep ocean site, around 60km from the shipping lanes and in 3,000 metres of water, also showed a drop in average weekly noise of 1.5 decibels, or around a 15% decrease in power, Barclay said. “This gives us an idea of the scale over which this reduction in noise can be observed.”

The reduction in ship traffic in the ocean, which Barclay compares to a “giant human experiment”, has had scientists racing to find out the effect on marine life.

Read the full story at The Guardian

Ocean warming is changing the relationship coastal communities have with the ocean

September 11, 2019 — Climate change has made record-breaking heatwaves all the more likely, both on land and beneath the ocean’s surface. As the world’s ocean sucks up carbon dioxide from the atmosphere—as well as most of the additional heat being trapped by global warming—it is undergoing some significant changes.

Marine heatwaves—prolonged periods of unusually —are one of those changes. These  are increasing in frequency around the globe and wreaking havoc on marine ecosystems.

As an oceanographer, I study the many ways oceans change—from week-to-week, year-to-year and, of course, over decades and centuries—to better understand the changes that are underway and the far-reaching impacts they may have on  and the communities that rely on them.

Read the full story at PHYS.org

Following the food trail to help right whales

July 25, 2019 — Scientists are gathering data on a flea-sized, fat-rich organism that could be key to predicting where North Atlantic right whales venture in their search for food in the southern Gulf of St. Lawrence.

A team from Dalhousie University and the University of New Brunswick is taking samples of copepods—a tiny zooplankton that is the primary food source for the massive  who scoop them up in dense patches.

Hansen Johnson, a Ph.D. candidate in Dalhousie’s Department of Oceanography, says the information could help indicate where the whales may travel as they seek out food and better protect them against their : ship strikes and fishing gear entanglements.

“It’s driven by this pressing need to figure out where  are going to be so management measures can be as effective as possible,” he says. “We think the whales are coming here to feed, so if we can find the food we can find the whales.”

Read the full story at PHYS.org

Lobsters unharmed by Atlantic Canada salmon farm, 8-year study finds

March 22, 2019 — SEAFOOD NEWS — An eight-year study of lobsters living below a salmon farm off New Brunswick’s Grand Manan Island found the aquaculture operation had no impact on the crustaceans’ abundance, size or growth.

The peer-reviewed, industry-funded study was published this month in the Canadian Journal of Fisheries and Aquatic Sciences.

Its authors say it’s the most in-depth examination of its kind in Atlantic Canada.

“There isn’t anything like this. Any surveys that have been done have been sort of cursory,” said Jon Grant, the study’s lead author and a Dalhousie University oceanographer.

How the study worked

The study involved divers visiting a sample area under the Benson Aquaculture salmon farm at Cheney Head off Grand Manan in 2008, and returning every August and September.

To establish a baseline, surveying started before the fish farm opened. The study covered two production cycles at the farm, which uses pesticides to control sea lice and has been opposed by lobster fishermen.

It also included a fallow period and a farm expansion to 336,000 fish from 10,000 during the second production cycle.

An identical survey was conducted about a kilometre outside the farm.

By the time the project ended in 2015, divers had counted 1,255 lobsters inside the farm and 1,171 outside.

What the study found

“In both cases, whether it was on the farm or off the farm, over those eight years the abundance of lobsters went up. A lot. By 100 per cent or more. And there was no difference in those lobsters in any way — in their size, in their sex or their abundance, whether on or off the fish farm,” Grant told CBC News.

“We don’t detect any evidence that the fish farm affected behaviour, growth or abundance of those lobsters.”

He said the study proved one hypothesis: the population inside or adjacent to the farm matched growth seen elsewhere in lobster fishing areas.

“It reflects the fact that the fishery is ongoing and it’s thriving and that fish farming does not seem to have impacted it, at least in eastern New Brunswick,” said Grant, who is funded by New Brunswick-based Cooke Seafoods and holds the NSERC-Cooke industrial research chair in sustainable aquaculture.

Surveys ordered by government regulators

The surveys were a requirement of the federal Department of Fisheries and Oceans and the New Brunswick government. The Atlantic Canada Fish Farmers Association funded the study.

The field work was carried out by SIMCorp, a New Brunswick-based marine environmental consulting firm that works for the aquaculture industry in Atlantic Canada and Maine.

SIMCorp is recognized as the standard for aquaculture, said Grant.

Tara Daggett, a SIMCorp biologist and co-author of the study, said the results are encouraging news for the aquaculture industry.

“We can fairly say aquaculture can coexist with fisheries and other species. It has a place,” she told CBC News.

However, Daggett cautioned the results only reflect what happened at one fish farm.

“The fish farm is typical of Grand Manan with sandy and cobbled bottom, but in science we don’t extrapolate. We need to test at other sites.”

This story was originally published on SeafoodNews.com, a subscription site. It is reprinted with permission.

Marine life worse off inside ‘protected’ areas, analysis reveals

December 27, 2018 — Destructive trawling is more intense inside official marine sanctuaries, while endangered fish are more common outside them, a startling analysis of Europe’s seas has revealed.

It shows that far from conserving sealife, many legal marine protected areas (MPAs) are being damaged by industrial fishing. The work has exposed “the big lie” behind European marine conservation, experts say, with most MPAs completely open to trawling.

The researchers were able to assess the activity of fishing vessels in great detail thanks to satellite tracking equipment that is now compulsory on ships. They compared this with scientific data on the health of sea areas and looked at more than 700 MPAs, covering 16% of Europe’s territorial waters. In total, MPAs cover 29% of Europe’s waters.

This revealed that commercial trawling activity was on average almost 40% higher inside MPAs than in unprotected areas. Furthermore, endangered and critically endangered fish species such as sharks and rays were five times more abundant outside the MPAs.

“It should be the reverse,” said Prof Boris Worm, at Dalhousie University in Canada, who led the research. “When something is called a protected area, it actually needs to be protected. We know that when areas are actually protected they deliver: species recover, biodiversity increases and fisheries benefit as well, as fish become more abundant and spill outside these areas.

Read the full story at The Guardian

High seas fisheries play limited role in feeding the world

August 14, 2018 — A recent study undertaken by a team of fisheries and social scientists found that fishing fleets operating outside of national waters contributed to less than 3 per cent of the world’s seafood supply.

Scientists from Dalhousie University, New York University and National Geographic paired a global database of marine catches developed by researchers at the University of British Colombia with a seafood trade database maintained by the United Nations Food and Agriculture Organisation. They analysed the data, considering the amount of fish and marine invertebrates produced by marine capture fisheries and comparing it to those produced by freshwater fisheries and aquaculture.

The team found that a much lower volume of seafood was produced by the high seas fisheries, with most of the catch destined for upscale EU, US and Asian markets. China and Taiwan account for one-third of the total high seas catch.

Lead author Laurenne Schiller, PhD student at Dalhousie University said: “I think many people have the misconception that because the area is so large, the high seas must be contributing a massive supply of food to the world, but that’s just not the case. Only a handful of countries are fishing in the high seas and the fish they catch are not feeding those most in need”.

The findings of this study are against the common misconception that high seas fisheries are important for food security. Less than 40 species are targeted by fisheries in the high seas, and only one species, the Antarctic toothfish, is exclusively caught in this are of the ocean. Marketed as Chilean sea bass, this fish can easily sell for over $50 per kilogram.

Read the full story at New Food

Researchers map hot spots of transfer of fish catch at sea

July 26, 2018 — It could be considered the global CSI for high seas fisheries. In two new groundbreaking studies, researchers from Dalhousie University, Global Fishing Watch and SkyTruth have applied cutting-edge technology to map exactly where fishing boats may be transferring their catch to cargo vessels at sea.

Known as transshipment, the practice increases the efficiency of fishing by eliminating trips back to port for fishing vessels. However, as it often occurs out of sight and over the horizon, it creates major challenges, including enabling illegal, unreported and unregulated (IUU) fishing.

“Because catches from different boats are mixed up during transshipment, we often have no idea what was caught legally and what wasn’t,” said Kristina Boerder, a Ph.D. student in Dalhousie University’s Department of Biology and lead author on the Science Advances paper, published this week.

Transshipment can also facilitate human rights abuses and has been implicated in other crimes such as weapons and drug trafficking. It often occurs in the high seas, beyond the reach of any nation’s jurisdiction, and where policy-makers and enforcement agencies may be slow to act against an issue they cannot see. By applying machine learning techniques to vessel tracking data, researchers are bringing unprecedented transparency to the practice.

“So far, this practise was out of sight out of mind, but now that we can track it using satellites, we can begin to know where our  truly comes from,” says Dr. Boris Worm, a Marine Biology Professor in Dalhousie’s Faculty of Science, and co-author of the Science Advances paper.

Read the full story from the Global Fishing Watch at PHYS