Research
A Baltimore, Maryland startup has come up with a novel way of battling Viral Nervous Necrosis (VNN), a disease that affects over 40 aquaculture species worldwide.

Dr Ken Malone, CEO of startup VakSea Inc, says the aquaculture industry’s big problem has not been the absence of effective vaccine, rather, it is in the way those vaccines are delivered.

“Current methods of delivering vaccines to fish involves injecting fish with vaccine one by one, which is expensive, labor intensive, and stressful to the fish,” says Malone.

VakSea grows the vaccine inside insect larvae, grinds up the larvae, mixes it into fish feed, then feeds it directly to the fish. When the fish eats the feed, they become immune to the disease.

The startup’s proprietary vaccine technology was developed at the University of Maryland Baltimore County in the lab of Dr Vik Vakharia beginning in 2014. VakSea filed a provisional patent application in 2016. It is now developing a pellet-based vaccine aimed at protecting European seabass juveniles from VNN and hopes to get it to market over the next 12 to 18 months.

VNN “damages the central nervous system in susceptible fish species and typically affect younger stages of fish (larvae, fry, fingerlings), although older, market-size fish can be affected as well, with losses ranging from 15–100 percent,” according to University of Florida-IFAS Extension researcher Roy P. E. Yanong, in his paper Viral Nervous Necrosis (Betanodavirus) Infections in Fish.

“Infected larvae and juvenile stages often show abnormal swimming behaviour, including vertical positioning and spinning; flexing of the body,” he wrote.

Species susceptible to VNN include red drum, cobia, sea bass, barramundi, gilthead seabream, Pacific bluefin tuna, various grouper species, various flatfish species including halibut and Japanese flounder, and tilapia.

Malone is confident of the potential of VakSea’s proprietary vaccine technology in other species. “We’ve proven it out on the nervous necrosis virus and we know it’s going to work on a large number of species and a large number of other diseases,” he says.



There’s plenty of environmentally suitable areas around the world for marine aquaculture but factors other than space availability could limit its development, a study suggests.

The study, Global estimation of areas with suitable environmental conditions for mariculture species, defined “suitable areas” as those that can support the physiological needs of farmed species for sustainable mariculture production.

The study estimates that 72,000,000 km2 of ocean would be environmentally suitable to farm one or more species. About 92 percent of the predicted area or 66,000,000 km2 is environmentally suitable for farming finfish, 43 percent or 31,000,000 km2 for molluscs and 54 percent or 39,000,000 km2 for crustaceans.

The University of British Columbia study team, led by Muhammed A. Oyinlola, suggests that suitable mariculture areas along the Atlantic coast of South America and West Africa appear to be most under-utilized for farming.

“Our results suggest that factors other than environmental considerations are currently limiting the potential for mariculture expansion in many areas,” says the study.

The limiting factors include: the socio-economics of producing countries, including capacity and political instability; technology, its availability and cost effectiveness; trades; aqua feed availability; aquaculture development-related policies and competition for space within countries’ exclusive economic zones (EEZs), for instance — shipping, oil and gas, as well as tourism — all play major roles in the development of mariculture operations and their future expansion.

The results reflect those of an earlier study, Mapping the global potential for marine aquaculture, conducted by UC Santa Barbara researcher Rebecca Gentry, et al.

After 10 years of research Nofima scientists have finally “cracked the code” to produce sterile farmed salmon.

 Inducing sterility in farmed salmon will make them unable to interact genetically with wild salmon populations.

"In practice we don’t touch the genes, but affect a protein that is necessary to enable the fish to produce gametes,” said senior researcher Helge Tveiten.

They have not seen any indications that the fish will become sexually mature or develop the urge to migrate in order to spawn.

Paving the way for the research was a previous study carried out on zebra fish, which identified a few genes that are decisive in the development of gametes.

“The salmon we have researched do not develop gametes, and will never be sexually mature,” Tveiten added. “We see a tiny egg sac in the female fish, but no eggs are formed. The male fish develops what appears to be normal sexual organs, but they don’t have sperm cells.”

Tveiten’s work is part of the SalmoSterile research project financed by the Research Council of Norway. The project is a collaboration between the Norwegian Institute of Marine Research (NIMR) and several major industrial companies, including AquaGen.

A scientist at Fisheries Oceans Canada (DFO) has developed a diagnostic tool that could be used to rapidly diagnose early signs of infectious disease in fish.
Microalgae are promising alternatives to fishmeal but their limited availability and high price prevent feed industry from using them, according to a Norwegian study.
A study translated into dollars and cents the economic gains from various seafood labels, including “certified organic” and locally grown.
Researchers at Auburn University are ready to field-test a vaccine against the deadly columnaris disease that can affect nearly all freshwater fish species and causes millions of dollars in annual losses in catfish aquaculture alone.

Lab trials over the past seven years have shown the Auburn vaccine has outperformed the only vaccine currently available on the market, the researchers said. It also targets the two types of bacteria that cause columnaris disease, Type I and the more destructive and more prevalent Type II. Currently available vaccine on the market addresses only Type I.

In vaccine trials of Nile tilapia and catfish, the vaccine increased survival rates by 66 and 17 percent, respectively, over the currently available vaccine, reported the Auburn University College of Agriculture paper.

Field-testing of the vaccine is funded by a $321,000 grant from the US Department of Agriculture. It will take place in 400 acres of Auburn University ponds.

“At this point in our research, we need data on a larger scale to successfully commercialize the vaccine,” research team leader Cova Arias told the Alabama Newscenter. “We will use this most recent grant to fulfill our gap of information.”

Responding to strong market demand for sea cucumbers in China, Alaska- and Washington-based researchers are developing hatchery and grow-out techniques for the indigenous giant red sea cucumber (Parastichopus californicus).

Farmed salmon contains fewer environmental pollutants than its wild counterpart, according to a Norwegian study that’s been described as the biggest research of its kind so far. The study involved 100 samples of wild salmon caught in the sea in Northern Norway, and 100 samples of farmed salmon.

The demographics and purchasing behaviour of seafood consumers present a host of challenges and opportunities, says Matt Lally, Manager, Analytics and Insight for Nielsen Perishables, a consultancy firm on fresh seafood for the marketplace.

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