Saving Seafood

Scientists Say Feeding Fish Soy, Not Fish, More Sustainable

Editor’s Note: One key aquaculture issue not addressed by the article is the importance of marine ingredients in ensuring that farmed seafood diets contain enough omega-3 fatty acids and other nutrients. Marine ingredients like fish meal and fish oil are currently the best way of transferring these nutrients to farmed fish and on to consumers. To learn more about aquaculture and marine ingredients, view this video.

November 22, 2015 — SIOUX FALLS, S.D. — Research supported by the soybean industry is looking to convert some farm-raised fish into vegetarians.

A South Dakota State University fisheries scientist is developing a soy protein feed that’s tasty and easily digestible to eventually reduce the industry’s need for using wild-caught fish as food for farm-raised fish.

Much of the tilapia, Atlantic salmon and catfish that Americans toss into their shopping carts are raised in fish farms, where companies traditionally feed them pellets containing anchovy, menhaden and herring. The harvest of those small species has pretty much flat-lined, SDSU professor Mike Brown said, and humans’ increased demand for fish has driven up the cost of creating the pellet feed.

“We’ve fully exploited that resource,” he said, noting that the goal is to create a more sustainable – and cheaper – food source. Traditional fish feed is currently costing between $1,450 and $2,000 per ton, while soybean meal runs about $425 per ton, Brown said.

But some environmentalists worry that feeding fish species an uncommon food source could produce excess waste that muddies up inland tanks or offshore waters where fish are raised.

Read the full story at the New York Times

FDA OK’s genetically modified salmon

November 20, 2015 — For the first time, Americans will be able to dine on a genetically altered animal, after federal regulators on Thursday approved a Massachusetts biotechnology company’s bid to modify salmon for human consumption.

After years of testing the company’s modified fish, regulators said there are no “biologically relevant differences” between the so-called AquAdvantage salmon and other farm-raised Atlantic salmon. Still, for the time being the FDA has barred the fish from being cultivated in the United States and has issued strict regulations to prevent the modified salmon from breeding with those in the wild.

The decision was a big win for AquaBounty, which began seeking approval in the 1990s for its technique of inserting growth hormone genes from Chinook salmon and an eel-like creature called ocean pout into the DNA of Atlantic salmon. The faster the fish grow, the more the company can produce and sell, potentially reducing overfishing of the oceans and developing a new source of food for a growing global population.

Company officials said the federal approval would create a new industry in the United States, which they say imports 95 percent of its Atlantic salmon. But it was unclear how long it might take before the fish appear in supermarkets.

“AquAdvantage salmon is a game-changer that brings healthy and nutritious food to consumers in an environmentally responsible manner, without damaging the ocean and other marine habitats,” Ronald L. Stotish, the chief executive of AquaBounty, said in a statement.

Read the full story at the Boston Globe

Diners Who Order ‘Wild’ Salmon Often Get Cheaper Substitute

October 28, 2015 — That wild Alaskan salmon you ordered the last time you ate out might not be wild — or even from Alaska.

That’s the finding of a study by the conservation group Oceana, which says nearly half of the country’s favorite fish may be mislabeled and priced too high in restaurants and stores when it’s out of season.

Researchers performed DNA testing on 82 salmon samples collected in Virginia, Washington, Chicago and New York in the winter of 2013-2014.

They found 43 percent of the samples were mislabeled. The most common switch — accounting for two-thirds of the cases — was selling farmed Atlantic salmon as the more expensive wild-caught product.

A similar study by Oceana during the summertime commercial fishing season, when wild salmon is plentiful, found only 7 percent was mislabeled, suggesting supply-and-demand fuels the phenomenon.

Most of the mislabeled fish was found in restaurants, not stores — probably because large supermarkets are required to provide more robust information about the fish they are selling, the group said.

Read the full story at NBC News

Atlantic Salmon Smolts Survive the Dam but Die Downstream

August 4, 2015 — Salmon are famous for boldly fighting their way upstream to spawn. But their trip downstream as young smolts is no less heroic. In the case of Atlantic salmon, many must pass through or around dams, and new research reveals that even if they survive the initial hazard, they may suffer injuries that make them more likely to die days or weeks later in the estuary, where the river meets the sea. What’s more, the effects are cumulative: for each dam a smolt passes, its chance of dying in the estuary increases by 6 to 7 percent.

“The effects of dams aren’t limited to a 500-meter stretch below the dam, but extend tens of kilometers out to sea,” said Dan Stich, the lead author of the study, which appeared recently in the journal Marine and Coastal Fisheries. “In fact, the number of fish killed by the delayed effects of dams can be greater than the number killed at the dam itself.”

Atlantic salmon are endangered in the United States, and these findings suggest that making dam passage safer for smolts can help the recovery of the species.

Stich conducted the study as a Ph.D. student at the University of Maine and is now a biologist with NOAA Fisheries. John Kocik, a research fisheries biologist at NOAA and a co-author of the study, said, “We already knew that we were losing a lot of fish in the estuary. Now that Dan’s research has identified some critical mechanisms behind that loss, something can be done about it.”

Toll Booths along the River

For this study, scientists surgically implanted acoustic tags into 941 smolts in the Penobscot River between 2005 and 2013. Those tags emit a coded sound roughly once a minute that uniquely identifies the fish carrying it.

As the fish travel downstream, the sound is picked up by receivers that span the river and the mouth of the estuary. The receivers function like electronic tollbooths, logging each fish as it passes so that scientists can track its progress. When a fish stops moving, it is assumed to have died.

The acoustic tags are about the size and shape of the metal eraser holder on a standard wooden pencil. Experiments have shown that implanting them in the 5- to 7-inch smolts does not harm the fish enough to significantly skew the results of the study.

A Dangerous Passage

At almost 1,000 tagged smolts, this study was the largest of its kind on Atlantic salmon, and it gave scientists enough statistical power to tease apart the factors that influence smolt survival. Of all the variables tested—including temperature, hours of daylight, distance traveled, and many more—one of the factors that most affected a smolt’s chances of survival was the number of dams it passed on its way to the ocean.

In the Penobscot River, most smolts pass dams in sluices or spillways. Those diversions keep most fish out of the generating turbines, but the ride can be rough and leave the fish injured or partially de-scaled. That can make them more vulnerable to predators and less able to withstand saltwater when they first encounter it days or weeks later.

“There are a lot of things waiting in the estuary to eat them,” Kocik said, including cormorants, seals, and striped bass. “Any fish that’s injured is easy prey.”

Timing Matters

As they make their way downstream, the smolts transform into ocean-going fish. They become longer and slimmer, acquire the ability to excrete salt from their gills, and are soon ready to migrate thousands of miles to Greenland.

This study showed that if smolts hit the estuary at peak saltwater readiness, their survival rate increases by up to 25 percent. The study also showed that scientists can estimate when that optimum window opens based on variations in stream temperature. This new understanding has already changed the way hatchery managers time the release of their smolts.

As for the effect of dams on downstream survival, now that it has been measured it can be managed. Two dams were recently removed from the main stem of the Penobscot River. In addition, NOAA Fisheries, the Federal Energy Regulatory Commission, and dam operators are working to aid recovery by making the remaining dams more salmon-friendly.

A large fraction of Atlantic salmon die in the ocean, where little can be done to increase survival. But in freshwater, there are options. In addition to removing dams and improving fish passages, several projects are underway to restore freshwater spawning and rearing habitats.

“The best thing we can do is boost the number of fish going out,” Stich said. “And understanding how dams affect fish survival will help us do that.”

Read the story and watch the video from NOAA