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NEWS CONTINUED FROM PAGE 5 BLOOMING SEA LETTUCE! Doctoral student Alex Port from Germany, is spending three years in New Zealand researching why sea lettuce (Ulva species) is so abundant in Tauranga harbour at certain times of year. Alex is part of the Intercoast programme, a joint initiative between the University of Waikato and the University of Bremen in Germany, involving PhD students working on coastal research projects of global signifi cance in the two countries. His fi eld campaign will focus on the 2012-2013 growth period from early spring until next winter, during which time he will complete six intensive sampling studies of Tauranga Harbour, each lasting around three days. Each exercise will involve surveying the intertidal and subtidal distribution of sea lettuce at selected sites around the harbour, analysing water nutrient, oxygen and temperature levels, and using an underwater camera to locate crops of young ulva plants. The Bay of Plenty Regional Council is supporting the project through a scholarship and by providing data, information, and access to expertise which has been compiled over the past 20 years. Water Science and support manager Rob Donald says while monitoring has identifi ed a number of factors infl uencing sea lettuce blooms ,such as water temperature, sunlight, sediment distribution and coastal ocean processes, the key "trigger" factors are unclear. IHN-POSITIVE SALMON CULL STARTED Alex Port conducting field trials Alex Port with collection cage About NZ$19.5 million of farmed Canadian Atlantic salmon will not be heading for the North American market next year because of Infectious Haematopoietic Necrosis virus found on one farm in British Columbia. The virus causes IHNV disease which can kill up to 100 percent of exposed farmed Atlantic salmon. The last time the IHN virus was found in Atlantic salmon farms in British Columbia in 2003, estimated sales losses were around NZ$260 million. Atlantic salmon farms around Vancouver Island have formed an outbreak management team after the virus outbreak on one farm run by Mainstream Canada, led to a site quarantine and the cull of 560,000 fi sh. Tests confi rm IHN at Dixon Bay, north of Tofi no, BC. A second Sunshine Coast farm has identifi ed a "low positive result" in coho salmon samples. Grieg Seafood are conducting ongoing tests there. Mainstream's fi sh are not showing any signs of disease or signifi cant or unusual mortality, and internal monitoring and a voluntary isolation protocol has been instigated. Signs of IHNV disease in rainbow trout (Oncorhynchus mykiss) include hemorrhage and exophthalmia (pop-eye) (photograph at left), and skin darkening relative to lighter colored healthy fish (photograph at right) The IHN virus is carried by wild adult sockeye salmon, a number of which have already made their way through the area where the infected farm is located. An outbreak management team is in place on Vancouver Island that includes members from across the industry. Samples are being taken at all farm sites in Clayoquot Sound and on the east coast of Vancouver Island as a precautionary measure. Heightened bio- security procedures are in place and samples from visitor, boat and plane traffi c to farms are being tested. Mary Ellen Walling, executive director of the BC Salmon Farmers Association, said, "I don't think it's started yet on the east coast of the island but it will." The outbreak is expected to have little impact on the market because the virus exists in BC coastal waters and does not affect human health or food safety, but it does pose a risk to aquatic animal health and the economy. Mainstream's headquarters are in Oslo, Norway. It is a subsidiary of Cermaq, operating in Chile, Canada, Scotland and Vietnam. They produce 25,000 tonnes of fi sh in BC annually. The Dixon Bay farm is being depopulated and disinfected. Equipment that can't be disinfected like nets will be destroyed and the farm will be left to fallow without restocking for three or four months. Mainstream employs about 150 people and don't foresee any layoffs in the future. BC is the highest-cost producer of salmon in the world. The wholesale price of Atlantic salmon ranges from about NZD$7.50 to about NZD$9 per kilogram. BC's salmon farming industry is the fourth largest producer of farmed salmon in the world, and in 2009, 18 companies operated on 131 sites. The value of Atlantic farmed salmon was around NZD$600 million in 2010. Source: fi shfarmingXpert 14 ■ NZ AQUACULTURE ■ JULY/AUGUST 2012