Saving Seafood

New tool to improve ‘cleaner fish’ welfare in salmon farming

July 30, 2021 — Researchers at the University of Stirling have developed a new tool that fish farmers can use to improve the welfare of lumpfish—a species crucial to tackling the problem of sea lice in salmon.

Lumpfish are increasingly being used by the  industry as a ‘cleaner fish’ to remove parasitic sea lice, which cost the Scottish salmon industry alone an estimated £40m per year.

Because they are a relatively new fish to aquaculture, researchers are still establishing the optimum conditions for lumpfish .

In a new study, a team led by Dr. Sonia Rey Planellas at the University of Stirling’s Institute of Aquaculture has established the correlation between lumpfish growth weights and welfare, and turned it into a tool farmers can use to assess the health of the fish and take remedial action if required.

Dr. Rey Planellas says that “at the moment, in the UK we use Operational Welfare Indicators (OWIs) for fish welfare, but lumpfish are a different shape to many other fish, so it’s about identifying the best indicators for each species.”

“Fin damage is typically the indicator that is used, but in this study we found a more useful indicator was the correlation between growth weight relative to size and welfare.”

Read the full story at PHYS.org

Will plant-based fish food make aquaculture more sustainable?

April 12, 2019 — Replacing fish food with plants may not be as planet-friendly as it seems, according to a new study on the ecological impact of feeding soy and other land-grown crops to farmed seafood. These plant-based feeds are an alternative to, well, other sea creatures, which is what many species like shrimp and salmon eat in the wild. Published in the science journal Sustainability, the new study—which involved which involved an international and multidisciplinary team of experts—quantifies the effects that plant-based feeds have on land, water, and fertilizer use. The numbers that emerge challenge the prevailing notion that simply swapping fish-based fish food for plant-based fare can minimize the environmental footprint of aquaculture.

The interlocking limitations of fish-based feed, also known as fishmeal, have long confounded the aquaculture industry. For one, its ingredients—small, wild fish lower in the food chain, known as forage fish—are a finite resource. And as the global appetite for seafood continues to rise, so does the pressure to catch more. That means that fishmeal is becoming more costly and harder to source. As a result, producers have been trying to reduce their reliance in recent years.

“When shrimp farming became very popular 30 to 35 years ago, there was kind of a preference to grow as many shrimp as you can, as fast as you can, and get them out on the market,” says Cheryl Shew, a representative of specialty feed manufacturer Ziegler Bros. Inc. But like much of the industry, Ziegler began to experiment with soy as a partial substitute fishmeal in its feed products beginning in the early aughts, Shew tells me.

So why not just completely replace fishmeal with plants? It’s not as easy as it sounds—or as environmentally-sound, as it turns out.

Read the full story at The New Food Economy

Study questions sustainability of plant-based aquafeed

April 9, 2019 — A new study by researchers at the University of Stirling’s Institute of Aquaculture concludes that there is an urgent need for a paradigm shift in the definition of sustainable shrimp feed.

The global farmed shrimp industry has an estimated production volume around four million metric tons (MT), and has become one of the biggest consumers of fishmeal in the aquaculture sector. This has put pressure on aquafeed manufacturers to find suitable alternative ingredients that do not affect the health or growth rates of the shrimp.

However, substituting in plant-based alternatives to fishmeal may not be the panacea that ecological campaigners are counting on, according to the recently published research.

“The Sustainability Conundrum of Fishmeal Substitution by Plant Ingredients in Shrimp Feeds,” by Wesley Malcorps, models the effects of decreasing the inclusion of fishmeal in commercial diets.

“As demand for shrimp feed increases, feed manufacturers are shifting towards crop-based ingredients, in a move that is mainly driven by economic incentives. This is evidenced by looking at the relative price of fishmeal compared to common plant ingredients such as soy protein concentrate, cereal, and wheat gluten. Some consider the move to be a sustainable transition, as it reduces the dependency on a finite marine resource,” Malcorps told SeafoodSource. “However, a change in ingredients would shift resource demand from the oceans onto the land and could affect the nutritional value of shrimp.”

His team set out to model incremental fishmeal substitution by plant ingredients in feed for giant tiger prawns (Penaeus monodon) and whiteleg shrimp (Litopenaeus vannamei). The models were used to assess the consequent impact on marine and terrestrial resources such as fish, land, fresh water, nitrogen, and phosphorus.

Read the full story at Seafood Source

Breakthrough in omega-3 understanding could revolutionize feed industry

May 31, 2018 — A new study, led by the University of Stirling in Scotland, has led to a major discovery about the way in which omega-3 long-chain polyunsaturated fatty acids are produced in the ocean.

According to lead scientist Oscar Monroig from the university’s Institute of Aquaculture, the breakthrough challenges the generally held principle that marine microbes, such as microalgae and bacteria, are responsible for virtually all primary production of omega-3 fatty acids, which are essential for human health, and have been proven to be particularly useful in combating and preventing cardiovascular and inflammatory diseases.

Instead, an international team of scientists from the United Kingdom, Portugal, Spain, Japan, and Australia found that omega-3s can be created by many marine invertebrates.

“Our study provides a paradigm shift in understanding, as it demonstrates that a large variety of invertebrate animals, including corals, rotifers, molluscs, polychaetes and crustaceans, possess enzymes called ‘desaturases’ of a type that enable them to produce omega-3, an ability thought previously to exist almost exclusively in marine microbes,” Monroig said.

Read the full story at Seafood Source

 

Entrepreneurs getting creative with seafood byproducts

September 28, 2016 — Global fisheries are missing out on millions of dollars in profits from seafood byproducts – including fish oil, fishmeal and lesser-used parts of the fish such as the skin and intestines.

According to a recent study from the Marine Ingredients Organization (IFFO) and the University of Stirling Institute of Aquaculture (in Stirling, United Kingdom) found that, even though there is increasing availability of raw material from aquaculture byproducts, there is significant underutilization of by-products from both wild fisheries and aquaculture.

Fisheries could also be using their by-products for cosmetics, clothing leather, supplements and other products that are more profitable than fishmeal, Thor Sigfusson, founder of the Iceland Ocean Cluster, told SeafoodSource.

Nearly 20 million tons of raw material is used annually for the production of fishmeal and fish oil globally, according to the model used by the University of Stirling researchers. However, only around 5.7 million tons of by-products are currently processed to produce fishmeal and fish oil. An additional 11.7 million tons produced in processing plants which are currently not collected for marine ingredient production.

“If all fish were processed and all the byproduct collected, it is estimated that globally there would be around 36 million tons of raw material available, producing about 9.5 million tons of fishmeal and 1.5 million tons of fish oil,” according to the University of Stirling/IFFO report.

Read the full story at Seafood Source