Background Articles

A concentration of pelagic sharks was observed in an area of western Queen Charlotte Sound, British Columbia, during systematic shipboard line-transect surveys conducted (2004 to 2006) for marine mammals throughout coastal waters of British Columbia. Surveys allowed only brief observations of sharks at the surface, providing limited opportunity to confirm species identity. Observers agreed, however, that salmon sharks Lamna ditropis (Lamnidae) were most common, followed by blue sharks Prionace glauca (Carcharhinidae). Both conventional and model-based distance sampling statistical methods produced large abundance estimates (similar to 20000 sharks of all species combined) concentrated within a hotspot encompassing similar to 10\% of the survey region. Neither statistical method accounted for submerged animals, thereby underestimating abundance. Sightings were made in summer, corresponding with southern movement of pregnant salmon sharks from Alaska. The previously undocumented high density of these pelagic sharks in this location has implications for understanding at-sea mortality of returning Pacific salmon Oncorhynchus spp. (Salmonidae) and for assessing conservation status of sharks in Canada and beyond. We recommend that a dedicated Canada-US sightings and biological sampling programme be considered, perhaps under the UN Transboundary Species Fishery programme.

July 23, 2007 – Over the last five years, large, predatory Humboldt squid have moved north from equatorial waters and invaded the sea off Central California, where they may be decimating populations of Pacific hake, an important commercial fish.

All persons practicing veterinary medicine in North Carolina shall report these listed diseases and conditions to the State Veterinarian's office by telephone within two hours after the disease is reasonably suspected to exist.

Phytoplankton blooms are increasingly conspicuous along the world's coastlines, and the toxic effects of these blooms have become a major concern. Nutrient enrichment often causes phytoplankton blooms, which decrease water transparency, but little is known about the effects of such light regime changes on whole communities of the continental shelf. A series of simulations designed to evaluate the potential effects of shading by phytoplankton blooms on community organization were conducted using a balanced trophic model of the West Florida Shelf ecosystem and the Ecopath with Ecosim modeling approach. Many functional groups in the system were predicted to decline as benthic primary production was inhibited through shading by phytoplankton, especially when associated biogenic habitat was lost. Groups that obtain most of their energy from planktonic pathways increased when shading impact and associated structural habitat degradation were complemented by enhanced phytoplankton production. Groups predicted to decline as the result of shading by plankton blooms include seabirds, manatees, and a variety of demersal and benthic fishes and invertebrates. Some counterintuitive predictions of declines (mackerel, seabirds, and surface pelagics) resulted because these groups are somewhat dependent on benthic primary production. The overall effect of the simulated bloom-associated shading of benthic primary producers resembled a trophic cascade where the number of full cycles of biomass gains and losses was approximately equal to the number of trophic levels in the system (4.7). (C) 2003 Elsevier B.V. All rights reserved.

Efforts to encourage Icelandic fisheries to make use of Atlantic bluefin tuna catch quotas allotted to Iceland have yet to prove fruitful. While tuna goes for high prices, specialised ships are necessary to make tuna fishing profitable. Chartering foreign boats to develop tuna fishing experience within the Icelandic fishing industry would require authorisation from the […]

More than 100 salmon trollers packed a Sitka meeting Wednesday night with sharp questions about the future of an iconic Southeast Alaska fishery, facing what could be an unprecedented full shutdown of this year’s chinook trolling season. State officials are scrambling to open the fishery after it was effectively closed by a federal judge — but damage has already been done.

Worms infecting fish grow four times faster at higher temperatures and manipulate the behavior of fish.

A total of 80 stockfish fillets of Northeast Arctic cod (Gadus morhua), traditionally open-air-dried in northern Norway, was examined for the presence and viability of larval parasitic nematodes of the family Anisakidae. Anisakids (particularly those belonging to genera Anisakis and Pseudoterranova) are of public health and economic concern globally, since they are responsible for an underestimated fish-borne zoonotic disease called anisakidosis.

Data cited by the B.C. Centre for Disease Control suggests 75 per cent of wild Pacific salmon are infected with the parasite. If fish is to be consumed uncooked, killing the parasites requires it to be frozen at -20 C for at least a week, Young said. Most commercial sushi-grade seafood suppliers freeze at -40 C.

Landmark report says invasive species are major threat to biodiversity and dealing with them requires global cooperation

Scientists looking at salmon found in Arctic waters are still asking northern harvesters and fishers to submit any unusual catches in exchange for compensation. It's part of the Arctic Salmon Project, which is a collaborative effort involving Fisheries and Oceans Canada, scientists from the South and local hunters and trappers organizations.

There were no bugs buzzing around the lights in the parking lot.

In the much-higher water temperatures that lingered in the 2014-19 period, juvenile chum salmon metabolism was super-charged, meaning they needed more food, said the study, by scientists with the National Oceanic and Atmospheric Administration and the Alaska Department of Fish and Game. But the food that was available was of low quality — things like jellyfish instead of the fatpacked krill and other prey they normally eat, the study said.

An executive order issued by President Biden extends the ban on Russian seafood imports to include products processed in other countries, closing a loophole from previous sanctions.

Fish traps have a long history around the world, and a vast network in a Vancouver Island estuary reveals generations of ecological wisdom.

“Our results suggest that warming is both increasing freshwater habitat and improving early marine survival of pink salmon in the northern Bering Sea,” said Ed Farley, NOAA Fisheries biologist at the Alaska Fisheries Science Center, who led the study.

Pacific pink salmon (Oncorhynchus gorbuscha) were introduced in the Kola Peninsula for their valuable eggs in the 1950s. Since then, the species has spread along the entire Norwegian coast and will probably remain. This sudden increase in pink salmon numbers in Norway, thought to be linked to favourable climate conditions for pink salmon reproduction and survival, is expected to continue as water temperatures rise with climate change and large numbers of fish continue to arrive from Russia.

Rising temperatures and dwindling oxygen levels are decimating marine species. But humanity can avert mass die-offs by curbing fossil fuel use and other planet-warming activities.

Similar projects have proven successful in Germany and other Baltic countries. ”And finally it's Sweden's turn” says project manager Linnéa Jägrud..