Cows and horses aren’t the only fans of alfalfa. Yellow perch like it, too. That’s what Agricultural Research Service (ARS) scientists and their collaborators concluded when they fed the fish pellets made with a protein concentrate from the legume crop’s protein-rich leaves.

Information source: press release / USDA

They’re experimenting with alfalfa as part of a broader effort to find suitable alternatives to using fishmeal, a protein-rich ingredient in aquaculture feeds given to “farm-raised” finfish and shellfish. Aquaculture is the fastest-growing sector of the food industry worldwide, generating $1.37 billion in U.S. sales alone. However, there’s concern that increasing consumer demand for aquaculture products will outpace what the ocean’s wild-caught stock of sardine, anchovy, menhaden, and other small forage fish can supply as a fishmeal resource for aquafeeds.

According to Deborah Samac, who leads the ARS Plant Science Research Unit in St. Paul, Minnesota, formulating aquafeeds with plant-based proteins could help lessen the need for fishmeal in aquafeeds, reducing aquaculture’s impact on aquatic natural resources. Using nutritious, affordable alternatives to fishmeal could also ease the burden on pelagic fish populations, which are important members of the marine ecosystem and its inhabitants, particularly larger predatory species.

Soybean meal, barley, and algae are among alternatives being explored or already commercialized. Now, many of the same qualities that make alfalfa “Queen of the Forages” (and third-largest U.S. field crop) could put it on the aquafeed shortlist as well. These include a crude protein content of 15 to 22 percent and a rich assortment of vitamins, including A, B, and D, as well as minerals such as magnesium and copper.

Alfalfa is typically fed to dairy cows, beef cattle and horses as hay, silage or a direct forage. But it can also be “juiced” for its protein concentrate, and that’s the form Samac and her University of Minnesota (UM) collaborators used for their yellow perch feeding trials.

The actual formulation process can involve passing alfalfa leaves through a screw press, squeezing out juices, and then heating and centrifuging them to produce a protein concentrate, which is then dried and processed into small pellets along with other ingredients.

The feeding trial results showed that perch given pellets containing the alfalfa protein concentrate (APC) gained somewhat less weight than perch given fishmeal formulations. But there was little difference between their health, longevity, and overall wellbeing. Their fillet yields, quality, composition, and flavor were also similar.

According to Samac, alfalfa could help impart greater sustainability to the $133.5 billion global aquafeed market by virtue of the ecosystem “services” and other benefits the crop provides.

For example, as a legume, it is a superstar at naturally converting atmospheric nitrogen into a form that corn and other crops can use for their growth, alleviating the need to apply chemical fertilizers. Alfalfa’s robust growth makes it an ideal cover crop, anchoring the soil, retaining its moisture, helping it store carbon, and controlling weeds. Alfalfa flowers are also important food for both wild and domesticated bees, contributing to the latter’s production of honey, wax, and other products.

Samac said additional studies are underway to fine-tune the APC concentrations used in aquafeed formulations, evaluate different processing methods, and expand feeding trials, which include rainbow trout. Value-added uses for byproducts of the APC juicing process will also be explored, she added.

Her collaborators on the effort are Jessica Coburn, Scott Wells, Craig Sheaffer, Roger Ruan, and Nicholas Phelps—all of UM in St. Paul—and Gibson Gaylord of the U.S. Fish and Wildlife Service’s Bozeman Fish Technology Center. Collaborators on the expanded trials include Dong Fang Deng (University of Wisconsin-Milwaukee), Matt Digman (University of Wisconsin-Madison) and animal physiologist Brian Shepherd, with ARS’ Dairy Forage Research Unit in Madison, WI.

Source: Aquaculture Magazine, Oct 19 2020

As the population grows, and the global standard of living improves, humanity’s appetite for seafood is increasing. In 2020 seafood consumption reached an all-time high, with an average of 20kg consumed annually by every person on the planet.

Written by: editorial / Technology Networks.com

Up to now most of this was caught in the world’s freshwaters and oceans. But things are changing, and today half of all seafood consumed comes from farmed sources, called aquaculture. The sector is expected to double by 2050 to supply the increasing global demand.

UC Santa Barbara Assistant Professor Halley E. Froehlich has contributed to an evaluation of the complex interactions between human, environmental, and animal health parameters of this budding industry, a view scientists call the One Health framework. The study, published in the journal Nature Food, brings together a diverse team of scientists, economists, sociologists and policy specialists led by the Centre for Sustainable Aquaculture Futures — a joint initiative between the University of Exeter and the United Kingdom’s Centre for Environment, Fisheries and Aquaculture Science.

“Aquaculture is now being more widely recognized as an important part of our global food system,” said Froehlich, a faculty member in the departments of environmental studies and of ecology, evolution, and marine biology. “And it will continue to grow. So the question is, how do we plot that course in a more sustainable way?”

Aquaculture has played a major role in lifting millions of people out of poverty in many low and middle-income nations, but it faces a range of sustainability challenges. These include environmental degradation, overuse of antibiotics, release of disease agents and the requirement of wild-caught fish meal and fish oil to produce feed. Parts of the industry also engage in poor labor practices and gender inequality.

Negative societal impressions created by such examples mask aquaculture’s potentially significant benefits. Farming cold-blooded animals is very efficient from a nutrient perspective. Many species, such as oysters, don’t even require feeding. In addition, aquaculture can operate on a smaller footprint than many other forms of food production.

The new paper uses the One Health framework to lay out a set of metrics to include in national aquaculture strategies across the globe to improve sustainability as the industry expands. These include concepts like access to nutritious food and quality employment, the health of wild fish stocks and ecosystems and maintaining a small environmental footprint and resilience to climate change.

Communication, cooperation and coordination will be critical to the sustainable development of aquaculture as the sector grows. “If you don’t have that knowledge transfer — for instance, from scientists to policy-makers or farmers to scientists — these types of framework structures won’t go anywhere,” Froehlich said.

With that in mind, the authors collaborated widely on this report. “The paper results from extensive interaction between a wide range of academic experts in aquaculture, health, environmental and social sciences, economists, industry stakeholders and policy groups,” said senior co-author Charles Tyler from the University of Exeter.

The paper presents a strategy for developing aquiculture as well as the benchmarks to which we will measure its sustainability and success. “This is an important paper,” said lead author, Grant Stentiford of the Centre for Environment, Fisheries and Aquaculture Science, “acknowledging that aquaculture is set to deliver most of our seafood by 2050, but also that sustainability must be designed-in at every level.”

The One Health approach offers a tool for governments to consider when designing policies. “I hope it will become a blueprint for how government and industry interact on these issues in the future,” Stentiford added. “Most importantly, it considers aquaculture’s evolution from a subject studied by specialists to an important food sector — requiring now a much broader interaction with policy and society than arguably has occurred in the past.”

Some of these principles are already being applied in the European Union and in Norway, according to Froehlich, who has begun shifting her focus toward the industry in the United States, especially California. She is currently in the middle of a Sea Grant project collecting the most comprehensive dataset of marine aquaculture information from across all coastal states in the U.S. This includes practices, policies, and the hidden interactions with fisheries that influence how aquaculture is conducted in each state.

“Aquaculture is everywhere and nowhere at the same time,” Froehlich said. “People don’t realize how integrated it is into so many facets of marine ecology, conservation biology, and fisheries.”

Reference
Stentiford, G.D., Bateman, I.J., Hinchliffe, S.J. et al. Sustainable aquaculture through the One Health lens. Nat Food (2020). https://doi.org/10.1038/s43016-020-0127-5

Source:https://aquaculturemag.com/2020/08/11/how-can-sustainable-aquaculture-be-achieved-a-new-study-from-the-university-of-santa-barbara/

Temperature and carbon dioxide changes reduce the numbers of some species and promote the growth of algae, a University of Adelaide study found

• By Graham Readfearn / The Guardian

Heating of the world’s oceans could radically reorganize marine food webs across the globe, causing the numbers of some species to collapse while promoting the growth of algae, new research has warned.

Healthy marine food webs that look like a pyramid, with smaller numbers of larger predatory species at the top and more abundant smaller organisms at the bottom, could become “bottom heavy.”

The types of species that could become less abundant in the oceans are the same ones targeted by commercial fishing and also are socially and culturally important to many communities around the globe.

In the research, published in the journal Science, researchers at the University of Adelaide recreated a marine habitat in a series of 1,800-liter tanks and then subjected some to temperature and carbon dioxide changes.

Ivan Nagelkerken, a professor in the university’s Environment Institute who led the research, said gazing into the tanks after six months when the study period ended had not been a pretty sight.

“It looked bad,” he said.

After being subjected to higher temperatures and higher carbon dioxide, the rocks were overgrown with turf algae and the sandy bottom had a lot more slimy algae that is toxic to some species, he said.

The tanks recreated a habitat off the coast of Adelaide in Gulf St Vincent that was about 6m deep.

Many of the species placed into the tanks — including kelp, crustaceans and the multitude of different bacteria on rocks, sand and in sediment — were gathered from the gulf. Native fish and crabs were also added.

Twelve tanks of ocean water — known as mesocosms — were split into four groups. Temperature and carbon dioxide levels were not adjusted in one group.

In another four tanks, the water temperature was raised over the course of six weeks until they were 2.8oC higher than today.

Another group of tanks had their carbon dioxide levels adjusted to the equivalent of 910 parts per million in the atmosphere, causing the water to become less alkaline.

The habitat in the fourth group of tanks was treated to both higher temperatures and higher levels of carbon dioxide.

Both the carbon dioxide conditions and the temperatures reflect conditions expected towards the end of this century in a world where little is done to curb fossil fuel burning.

Nagelkerken said the results of the experiment remained relevant even if the world did act to slow down the rising levels of carbon dioxide in the atmosphere.

In 2011 a marine heatwave in Western Australia raised ocean temperatures more than 2oC for about 10 weeks. A study five years later found no recovery of the kelp — a vital component shaping the marine ecosystem there.

“That marine heatwave showed that even over just a few weeks, that caused the kelp to disappear,” Nagelkerken said.

He said the research showed that ocean heating “reshuffles species communities” with weedy plants and algae thriving, but the “abundance of other species, especially invertebrates, collapses.”

Nagelkerken said the changed pyramid that was fatter at the bottom and thinner in the middle, could eventually see larger predators also losing out.

In the study, the researchers write: “The top of food webs may eventually become depleted under future climate conditions or additional human disturbances.”

The small fish that were the predators in the tank resisted the impacts of warming, but the experiment showed the food they ate was becoming impoverished — an imbalance that could see the top predators struggling.

An ecological tipping point could be reached where “the top of the food web can no longer be supported,” the study says.

Nagelkerken said that in the real world, the impacts would vary depending on whether species could move to different areas. Some species would not be able to.

He said there was already evidence species were extending their ranges away from the equator as oceans got warmer and this, together with changes to the food webs, could also see traditional fishing grounds move, creating knock-on effects for communities that had been built around fishing.

“It’s not just climate change, but also our removal of predatory fish [through overfishing] and the addition of nutrients into the ocean. We have to consider all of that too,” he added.

Kirsty Nash, of the Institute for Marine and Antarctic Studies at the University of Tasmania, who was not involved in the research, said studying the resilience of marine systems was challenging, and the researchers had struck a balance between what was practically possible while giving an insight into real-world impacts.

“Developing this type of understanding is really important if we want to then address questions around the broader consequences of climate change for society, for example, are fisheries likely to suffer as a result of climate change,” she said.

The experimental findings in the tanks were likely only showing an “intermediate state” that was a prelude to the development of “radically different” food webs, she said.

She said many places in the world had fish that societies consumed, but that the study suggested would be impacted.

“These local fish are popular eating fish, so this would have implications for what’s available, but it does depend on the area and how culturally and socially acceptable that would be,” she said.

Sophie Dove, an associate professor at the University of Queensland, who has run large long-term mesocosm experiments, said the study adds to mounting evidence that under the current trajectory of carbon dioxide emissions “services will be lost from our most valued ecosystems.”

She said she would have preferred that the experimental conditions had more closely mirrored the daily and seasonal changes in light, temperature and carbon dioxide.

However, the experiment demonstrated that organisms at the bottom of the food chain — such as “relatively inedible slimy algae” — did well under the changing conditions, but small plants that helped give rocky reefs their structure “do very badly under warming and acidification,” she said.

Source: https://www.taipeitimes.com/News/editorials/archives/2020/08/18/2003741859

Like spirits passing between worlds, billions of invisible beings rise to meet the starlight, then descend into darkness at sunrise. Microscopic plankton’s daily journey between the ocean’s depths and surface holds the key to understanding crucial planetary processes, but has remained largely a mystery until now. A new Stanford-developed rotating microscope, outlined in a study published Aug. 17 in Nature Methods, offers for the first time a way to track and measure these enigmatic microorganisms’ behaviors and molecular processes as they undertake on their daily vertical migrations.

Taipei, April 17 (CNA) Taiwan has succeeded in breeding two new color variants in captive harlequin shrimps, a species of saltwater crustacean found in coral reefs in the tropical Indian and Pacific oceans, the Fisheries Research Institute (FRI) said Friday.

Wild harlequin shrimps that live in waters in the East Pacific typically have deep pinkish-purple spots with yellow edges, while those that live in the Indian Ocean and the West Pacific tend to be more brownish with a blue edge.

Through gene recombination and hybridization, people will now have the option of raising this type of pet shrimp in shades of indigo blue and cobalt blue in fish tanks, the institute said.

The aquarium fish market is currently the third largest pet market after dogs and cats in Taiwan, it said, indicating that the market for aquarium shrimp has increased significantly in recent years.

According to the FRI, the output value of ornamental shrimp in Taiwan exceeds NT$200 million (US$6.64 million) annually.

Based on statistics from the United Nations Food and Agriculture Organization (FAO), the institute said the global aquarium fish market in 2019 was worth approximately US$15 billion to US$20 billion.