When salmon is farmed in large-scale monocultures, the fish tend to become susceptible to disease and parasites. Researchers working for the organization Nofima have now found a way of combating the parasite salmon lice in fish farms without using any dangerous toxins. Wrasse loves to eat lice, so the researchers simply added wrasse to the salmon populations and the result was astonishing.

During the trials, the most efficient lice eater turned out to be the Ballan wrasse (Labrus bergylta). In addition to being highly efficient, it also gathered lice at lower temperatures than the other Wrasse species that took part in the experiment.

When Ballan wrasse was used, roughly 2-5% wrasse was needed for salmon living in sea cages. This means that a population of 100 000 salmon will need somewhere between 2 000 and 5 000 wrasse to stay deloused. A new larger project will now be prepared to make sure there is an adequate supply of the lice eaters in Norway. The project will go on for three years and has received funding from The Fishery and Aquaculture Industry Research Fund (FHF).

The effort which is now commencing is unique in both a Norwegian and global context. Norway is the only salmon-producing country that is using wrasse on a large scale to combat salmon lice,” says Arne Karlsen, managing director of FHF.

Removing large amounts of Ballan wrasse from the wild to keep in salmon farms could cause serious damage to the wild populations and the goal of the Norwegian project is therefore to cover at least 25% of the demand with farmed wrasse by 2013.

In addition to Nofima and FHF, the project will also involve SINTEF Fisheries and Aquaculture, the Institute of Marine Research and the Norwegian University of Science and Technology.

Several Norwegian projects are already taking a closer look at the Ballan wrasse, including a research venture concerning Ballan wrasse farming that started last year with funding totaling NOK 12 million from the Research Council of Norway, FHF and industry partners.

” It is estimated that the total Norwegian effort on Ballan wrasse farming is in the vicinity of NOK 100 million,” says Kjell Maroni, research and development director at FHF

The researchers will now have to find out how to carry out large-scale wrasse farming without being plagued by the same problems with disease and parasites as the salmon farms.



Salmon fry

The wild salmon of the North Pacific are becoming fewer in number as they are being forced to fight for their food and rapidly declining living space, as billions of farmed salmon are being released into the oceans every year, a study by researchers out of B.C. and Washington State explains.

The concern is coming from the fact that the salmon populations, mainly of the sockeye, pink and chum variety, across the Pacific Rim is much higher than usual.

“The total number of salmon out there is at an all-time high, in fact, the abundance is about double what it was in the 1950s,” commented a fisheries management scientist at Simon Fraser University, Randall Peterman, who is also a co-author of the newly published report.

Releasing a huge amount of artificially grown salmon to help and supply a food fishery is detrimental to the native salmon, he explains. “Hatchery fish have been causing deterioration in the wild population for some time.”

“The fact is that hatchery fish from one nation can influence the health of salmon stocks in another nation,” Peterman explains. The amount that these hatcheries release, especially in Alaska and Japan, has reached a level of an astounding five billion salmon a year and it’s continuing to increase. Which means that the salmon are under imminent threat.

First it’s overfishing, now it’s over fish releasing? Well I have an answer for you boys, grab the frying pan, it’s time for a fish fry…

Fish with Ich Credit: Dehai Xu, Ph.D

According to new research presented by Dehai Xu, Ph.D. at the 240th National Meeting of the American Chemical Society (ACS)*, a vaccine against the feared ich disease might be available in the foreseeable future.

Ich is a disease dreaded by hobby aquarists and professional fish farmers alike. It is caused by the ciliated protozoan Ichthyophthirius multifiliis (hence the name ich) and can easily kill of all the fish in an aquarium or fish pond. Fortunately, it seems to be unable to infect humans. Among aquarists, it is chiefly known as White Spot Disease since the parasites cause small white nodules to form on the skin and in the gills of infested fish.

Today, ich outbreaks in large commercial fish farms are often treated by adding hundreds of gallons of a formaldehyde solution to the water. This is far from an ideal solution, since formaldehyde can be toxic to both humans and fish. It is classified as a known human carcinogen by the WHO International Agency for Research on Cancer (IARC) and is associated with both nasal sinus cancer and nasopharyngeal cancer. And as anyone who has ever combated ich in an aquarium knows, ich treatment is something you have to do over and over again since the parasite is usually only sensitive to treatment during one of its multiple life stages. This means repeatedly adding large quantities of formaldehyde solution to the pond. Even when formaldehyde ich treatment is successful, it provides no long-lasting effects since the fish develops no immunity. If new outbreaks occur, a new treatment cycle has to be carried out.

It is therefore no surprise that the series of vaccine tests carried out by Dr. Xu and his colleagues Dr. Phillip Klesius and Dr. Craig Shoemaker, who are with the U. S. Department of Agriculture’s Agricultural Research Service (ARS) in Alabama, have sparked vibrant interest within the aquatic world. For anyone from commercial fish farmers to public aquaria and hobby fish keepers, an ich vaccine would be a dream come true.

“Outbreaks of the parasitic disease caused by Ichthyophthirius (Ich) can result in losses of 50-100 percent of fish,” Dr Xu explained while presenting the team’s findings at the ACS meeting. “The disease is very common, and almost every home fish hobbyist has encountered it. Once the parasite infects fish, and starts growing in the skin, fins, and gills, there is no really effective treatment. Ich causes losses estimated at $50 million annually. It would be much better to prevent the disease. To vaccinate against Ich, you would need much less medication, and it would not pose an apparent threat to the environment. And you would need just one treatment to make the fish immune for life.”

In their efforts to develop a vaccine, Xu and his colleagues have focused on the use of so-called trophonts.

The ich protozoa goes though three life stages:

• The ich trophozoite feeds inside the nodule (”the white spot”) on the skin or gill of the fish.

• The ich trophozoite falls off and becomes an ich tomont, i.e. it enters an encapsulated dividing stage. During this stage, the tomont is attached to plants, gravel or other objects in the environment.

• The ich parasite will then start dividing itself, producing trophonts. The trophonts will move around freely in the water, looking for fish to infect.

Trophonts burrow into the skin and fills of a fish and start to feed, thus completing the cycle. When Xu, Klesius and Shoemaker began their research project very little was known about how fish develop protective immunity to trophonts, so the researchers basically had to start from scratch.

Eventually, they were able to show that vaccination with live ich theronts and trophonts killed with high-frequency sound waves stimulated production of protective antibodies in channel catfish (Ictalurus punctatus)

“This study demonstrated that vaccines against Ich induced protective immunity and could provide a unique solution to prevent this parasitic disease through vaccination,” Xu said. “An Ich vaccine would have great impact by preventing the disease, minimizing loss of valuable fish and increasing profitability of aquaculture.”

Injecting fish in a laboratory setting is one thing, administering a vaccine to thousands or even millions of fish in a huge commercial farm is another, so the next goal will be to find a way of carrying out large-scale vaccinations. It might for instance be possible to produce a large quantity of Ich antigen and then creating a vaccine that can be administered as food or in a “bath”.

For aquarists however, injecting each fish with the vaccine might actually be a feasible solution, provided of course that an injectable vaccine would be produced for the aquarium market.

* http://portal.acs.org

There was a lot of mystery surrounding a disease which was rampaging through European Salmon farms, a disease which was wasting their hearts and muscles. Finally, through the use of Genome sleuthing, the mystery has been solved.

The disease is caused by a previously unknown virus. This identification does not mean that there is now also a cure for the disease, however it is a great step forward into solving the problem. Now that scientists have pinned down the disease and the genome, it is only a matter of time before a cure will be found.

“It’s a new virus. And with this information now in hand, we can make vaccines,” explained director of Columbia Univerity’s Center for Infection and Immunity, Ian Lipkin.

A couple of years ago, some Norwegion fisheries got into touch with Lipkin and asked for his aid in discovering what was going on in their Norwegion Salmon farms. They wanted to know what was causing the HSMI (Heart and Skeletal Muscle inflammation), the scientific name for an affliction which was identified in 1999 on one of their farms.

The fish which are infected are physically stunted, and have muscles so weak that they often have trouble swimming about, or even circulating blood around their bodies. This disease often results in death, so there is a great cause or concern. The reason there is so much concern is that the original outbreak was followed by 417 other in Norway and the United Kingdom, and every year there are more reports of the disease.. What is even more disturbing is that there have been reports of wild salmon being infected, which means that salmon which escape the farm are infecting the already low numbers of wild stocks. If something is not done to fix this problem, it could quite possibly spiral out of control, and have a devastating effect on not only local ecosystems but on the entire salmon market as we know it. “If the potential hosts are in close proximity, it goes through them like wildfire,” said Lipkin.

Lipkin and his team, which have already had great success in identifying mystery viruses, rigorously examined samples taken from infected salmon pens. They were looking for the DNA sequences which resemble sequences found in other viruses, and hopefully finding the HSMI-causing sequence. Lipkin compared the grueling process akin to solving a Sunday paper crossword. The researchers eventually found what they were looking for, and dubbed the virus piscine reovirus, or PRV. The virus was unveiled and explained in the issue of Public Library of Science one, published on the 9th of July.

Some viruses which are rather similar have been discovered on poultry farms, and cause muscle and heart disease in chickens. “Analogies between commercial poultry production and Atlantic salmon aquaculture may be informative,” The researchers wrote in the article. “Both poultry production and aquaculture confine animals at high density in conditions that are conducive to transmission of infectious agents.”

The results from these investigations might just be useful when the Obama administration comes up with its national policy for regulating aquaculture.

A genetically manipulated salmon, which has been tweaked to grow twice as fast as normal, is set to become the first genetically modified animal which will be approved for us to eat.

Food regulators, such as the FDA in the United States, are still deliberating whether the product, known as AquaAdvantage salmon, is even safe for human consumption, and also safe for the environment. They have managed to sign off on 5 of the 7 criteria needed for the product to hit the shelves.

The salmon contains a special type of growth hormone which would allow it to grow to a sifficient size in only 18 months, rather than 3 years, which is standard for this kind of fish.

AquaBounty, the Massachusetts company which came out with the fish, is insisting that it is safe, both for human consumption, as well as for the environment. They are hoping to be able to get approval for the product to go on sale within a few short months.

Ronald Stotish, the chief executive of the company, has said that it’s not that the fish will come out bigger than normal, it will just grow to full size within half the time. If approved, AquaBounty would sell fish eggs to fish farms.

Tiger Prawn

The boys in white lab coats over at CSIRO and in the prawn industry have managed to breed and improve upon Black Tiger Prawn, and they are producing bumper crops in aquaculture farms and have been winning awards.

These prawns are so good in fact, that they have even won FIVE gold medals at the Sydney Royal Easter Show for the past two years running, including “Champion of Show” which happens to be the most decorated award possible.

The boys in white over at CSIRO’s Food Futures Flagship have tweaked the Black Tiger Prawn DNA, to make sure that the breeding program they have running captures the elite of the group and boost performance of their stocks every breeding season.

For the past several years, about fifty percent of all the prawns sold in Australia were imported from other countries such as Vietnam and China, so developing a local prawn which breeds in captivity is an extraordinary gain for both the local prawn industry and hungry consumers wanting to buy local seafood.

Dr. Nigel Preston, leader of the CSIRO Food Futures Flagship, had this to say about this exquisite prawn. “The new prawn’s yield has exceeded all our expectations. The average industry productivity for farmed prawns is only five tones per hectare, so this year’s average yield of 17.5 tones per hectare is a major leap forward, these huge yields can be replicated year after year which means consistent supply of a reliable and high quality product – all vital factors for the long-term growth and prosperity of the Australian prawn farming industry.”

Aquaculture has yielded approximately 17.5 tones per hectare, more than double the average production in the industry, all thanks to Dr. Preston’s super prawn. Several of the ponds produced 20 tones per hectare, and one even produced a record breaking yield of 24.2 tones per hectare.

Theorists say that if the rest of the Australian Black Tiger Prawn industry followed suit, and adopted this new DNA tweaking technology, Australia’s production could more than double, adding a $120 million boost to the annual value of the industry by the year 2020.

Mr. Nick Moore, general manager of Gold Coast Marine Aquaculture, had this to say about this revolutionary new prawn, and about Dr. Preston’s work.. “Thanks to outstanding work by the staff here, aided by close collaboration with our partners at CSIRO, we have just finished a prawn breeding season that can only be described as staggering, not only have we achieved national and international yield records with no reduction in quality or taste, these prawns are grown in a specially designed, environmentally sustainable production system. This production system and the new breeds have produced a perfect prawn with beautifully textured meat, rich color, robust size and a great taste. The awards (Sydney Royal Easter Show) are professionally judged on many criteria including size, color, taste and texture, so the results speak for themselves.”

With predictable output, and supped up prawn.. Australia is set to make its mark on the prawn industry.

The low temperatures that’s been holding the state of Florida in a firm grip this winter is causing troubles for tropical fish raised in outdoor ponds. Aquarium fish farmers report losing up to 50% of popular tropical species to the cold, and a severe guppy shortage has already emerged – boosted by the fact that Americans are more inclined to purchase guppies and other aquarium inhabitants during the winter season.

Roughly half of the tropical fish sold in the United States is raised in Florida, a state heavily dependant on its warm climate. The fist fish farmers showed up here as early as the 1930s when it was still possible to purchase cheap land around Miami, but nowadays a majority of the fish Florida farms is found in the lake-rich part of Florida located between Tampa and Orlando. Up until a few years ago, the number one cargo shipment out of Tampa International Airport was tropical fish.

Fish native to tropical parts of the world normally find it difficult to stay alive if the water temperature drops below 60 degrees F (15 degrees C) and even temperatures around 70 degrees F (20 degrees C) may have a detrimental effect on their immune system. It is therefore easy to imagine what happens if the air temperature suddenly drops below the freezing point – as it has done in Florida this winter.

And even in situations where the cold isn’t severe enough to instantly kill the fish it can send them into a sedentary state where they fail to hide from predators like hungry birds, especially if living in unplanted ponds offering few places to hide. Many fish eating birds have been forced to see their normal hunting grounds being sealed off by ice and fish farms struggling to keep the water temperature up constitute a highly appealing alternative when the hunger sets in.

In desperate attempts to save their fish from freezing to death or being eaten by predators, Florida farmers have been covering their ponds with plastic sheets and pumped in warm water. When the cold turned out to be more than just a short dip, those who could scrambled to get as many fish as possible indoors. Many farmers have been forced to prioritize older fish close to the size needed for shipping, leaving younger fry behind to die.

Farmers that have lost more than 50 percent of their fish are entitled to financial relief from the Department of Agriculture if they file a crop insurance claim.

Telling a wild salmon from a farmed one can be tricky, especially if you don’t want to kill or injure the fish in question. To solve this problem, Dr Elizabeth Adey of the Scottish Association for Marine Science (SAMS) have developed a way of using fish scale analysis to determine the origin of a salmon.

Fish scales grow like tree rings and preserves a chemical record of the water in which the fish lived as each new section of the scale was formed. The new method, which was developed in collaboration with the National Oceanography Centre in Southampton, checks the amount of manganese present in the fish scale. During her work, Dr Adey discovered that the scales of farmed salmon have a very high manganese content compared to the levels found in scales coming from their wild counterparts.

“This is probably caused by manganese supplements in fish food, and also because conditions underneath the fish cages promote recycling of manganese in the water column,” Dr Adey explains. Using the new method, Dr Adey and her team was able to distinguish between farmed and wild salmon with 98% accuracy.”Because of its non-destructive nature, this technique could be used to assess the proportion of farmescape salmon present in any river, and therefore identify where additional conservation and wildlife protection measures are needed,” says Dr Trueman, a geochemist with the University of Southampton’s School of Ocean and Earth Science, based at that National Oceanography Centre. “Salmon farming is a big, intensive business. In 2006, around 130,000 tonnes of salmon were farmed in Scotland for the table. Wild populations of Atlantic salmon are in serious decline across their whole range and the total wild population returning to Scottish rivers in the same year is estimated at less than 5000 tonnes. Wild fish are rare and expensiveso there is a strong incentive for fraudulent labeling. Farmed fish also escape into rivers, harming the wild population. Unfortunately, it can be difficult to distinguish between farmed and wild fish.“

In the future, the new technique may also be able to point out which individual fish farms that need to implement more efficient methods for keeping their salmons in. In some Norwegian rivers, more than 50 percent of the salmon are now escapees. Escaped fish can carry disease to wild populations, and there is also a risk of genetic pollution since farmed fish haven’t gone through the same natural selection process as wild fish.

A Japanese team of scientists are now announcing that they are close to completing genome sequencing of the Bluefin tuna. Once they have reached this goal, their next project will be to use their knowledge to create a tuna breeding program for a new type of tuna specially designed for aquacultures.

The wild tuna populations have become severely depleted due to overfishing and the WWF has warned that the Atlantic Bluefin tuna will be eradicated within three years unless radical measures are taken to safeguard remaining specimens.

“We have already completed two computer sequencing runs and have around 60 per cent of the tuna genome,” says Dr. Kazumasa Ikuta, director of research at the Yokohama-based Fisheries Research Agency. “We expect to have the entire sequence in the next couple of months. We plan to use the sequence to establish a breeding programme for bluefin tuna as most aquaculture farmers presently use wild juveniles. We want to establish a complete aquaculture system that will produce fish that have good strength, are resistant to disease, grow quickly and taste delicious.”

The genome sequencing is the result of the collaborative efforts of scientists from Japan’s Fisheries Research Agency, Kyushu University, and The University of Tokyo.

The work towards replenishing depleted stocks of wild sea cucumber with captive hatched ones is moving forward at a steady pace; two Philippine hatcheries has now successfully managed to hatch sea cucumbers outside their natural habitat and one batch, comprised of roughly 2,000 juveniles, has been released inside sea pens in the Philippines.

The sea cucumbers, a broad range of species belonging to the family Stichopodidae, are currently facing both overharvesting and habitat destruction in the wild, and the two Philipine hatcheries are both part of a research project carried out by the University of the Philippines Mindanao (UPM); a project aiming to mitigate the problem of overharvesting through sea

farming.

The first hatchery is a 6,000-square-meter laboratory located within a Barangay Binugay resort owned by the JV Ayala Group of Companies, while other one is situated inside Alson’s, an intensive tilapia operator.

The Barangay Binugay laboratory does not have any breeding stock; instead it collects the eggs from wild sea cucumbers, place them in a tank and fertilize them using drops of sperm – a method inspired by a Vietnamese sandfish sea cucumber hatchery and grow-out facility in tilapia .

The first Philippine batch of tiny cucumbers, each weighing no more than three grams, has now been released inside sea pens near the Barangay Binugay laboratory. Carefully, each individual cucumber was buried just below the surface of the soft sea bottom inside 78-square-meter Australian-designed sea pens.

With a history dating back to at least the Sultanate days in Mindanao, sea cucumber trading is a time honoured tradition as well as an important source of income for the Philippines. The country is currently the second largest exporter of beche-de-mer (dried sea cucumber) in the world, second only to neighbouring Indonesia, and diminishing cucumber populations are threatening the livelihood of countless families.

Beche-de-mer is currently priced at roughly 4,500 Philippine pesos per kilogram (roughly 94 USD/kg), and since large specimens are becoming increasingly rare purchasers are no longer very discerning when it comes to size. Even small cucumbers that should have been left to mature can now be sold to unscrupulous purchasers.

Did you know…..?

… that sea cucumbers are known as the earth-worms of the sea since they recycle detritus and burrow under the sand? These animals carry out an essential ecological task as they continuously shift and mix the sea bead and if they were to disappear it would have serious consequences.

… that at depths below 8.8 km (5.5 miles), sea cucumbers comprise 90% of the total mass of the macro fauna?

… that sea cucumbers aren’t appreciated as food only; some people believe them to be effective against arthritis and high blood pressure?

…that sea cucumbers have been observed engaging in mass-spawnings triggered by the moon? One species is for instance known to spawn three nights after the full moon, while two other species have been seen spawning three nights after the first quarter moon.

… that sea cucumbers have been traditionally used as an aphrodisiac and that some people still use them for this purpose today?

…that large sea cucumbers often are harvested by so called hookah diving, where divers breathe through long tubes connected to an oxygen compressor aboard a boat instead of using normal scuba tanks.