Saving Seafood

Fish Stocks Are Declining Worldwide, And Climate Change Is On The Hook

December 14, 2015 — For anyone paying attention, it’s no secret there’s a lot of weird stuff going on in the oceans right now. We’ve got a monster El Nino looming in the Pacific. Ocean acidification is prompting hand wringing among oyster lovers. Migrating fish populations have caused tensions between countries over fishing rights. And fishermen say they’re seeing unusual patterns in fish stocks they haven’t seen before.

Researchers now have more grim news to add to the mix. An analysis published Monday in the Proceedings of the National Academy of Sciences finds that the ability of fish populations to reproduce and replenish themselves is declining across the globe.

“This, as far as we know, is the first global-scale study that documents the actual productivity of fish stocks is in decline,” says lead author Gregory L. Britten, a doctoral student at the University of California, Irvine.

Britten and some fellow researchers looked at data from a global database of 262 commercial fish stocks in dozens of large marine ecosystems across the globe. They say they’ve identified a pattern of decline in juvenile fish (young fish that have not yet reached reproductive age) that is closely tied to a decline in the amount of phytoplankton, or microalgae, in the water.

Read the full story at NPR

 

Marine Invasive Species Benefiting from Rising Carbon Dioxide Levels

November 6, 2015 — Ocean acidification may well be helping invasive species of algae, jellyfish, crabs and shellfish to move to new areas of the planet with damaging consequences, according to the findings of a new report.

Slimy, jelly-like creatures are far more tolerant of rising carbon dioxide levels than those with hard structures like corals, since exposed shells and skeletons simply dissolve away as CO2 levels rise.

The study, conducted by marine scientists at Plymouth University, has found that a number of notorious ‘nuisance’ species – such as Japanese kelp (Undaria pinnatifida) and stinging jellyfish (Pelagia noctiluca) are resilient to rising CO2 levels. Published in Research and Reports in Biodiversity Studies, it notes that in the tropics, coral reefs face a host of interconnected problems (bleaching, corrosion, disease, spreading seaweed, invasive species) that are all caused by rising CO2 levels.

Read the full story from Alaska Native News

Toxin Taints Crabs and Kills Sea Mammals, Scientists Warn

November 4, 2015 — The authorities in California are advising people to avoid consumption of crabs contaminated by a natural toxin that has spread throughout the marine ecosystem off the West Coast, killing sea mammals and poisoning various other species.

Kathi A. Lefebvre, the lead research biologist at the Wildlife Algal Toxin Research and Response Network, said on Wednesday that her organization had examined about 250 animals stranded on the West Coast and had found domoic acid, a toxic chemical produced by a species of algae, in 36 animals of several species.

“We’re seeing much higher contamination in the marine food web this year in this huge geographic expanse than in the past,” Ms. Lefebvre said.

She said that the toxin had never before been found in animals stranded in Washington or Oregon, and that there were most likely greater numbers of contaminated marine mammals not being found by humans.

The California Department of Public Health recently advised people to avoid consumption of certain species of crabs because of potential toxicity. Razor clam fisheries in Washington have been closed throughout the summer for the same reason.

In a statement released on Tuesday, the California department said that “recent test results” indicated dangerous levels of domoic acid in Dungeness and rock crabs caught in California waters between Oregon and Santa Barbara, Calif.

Read the full story at The New York Times

The Economist: Particle biology

October 10, 2015 — Filter-feeding bivalve molluscs, such as mussels, oysters, scallops and clams, are a useful and tasty source of protein. They can, though, also be harbingers of illness. A filter-feeder lives, as the name suggests, by trapping and consuming particles (mostly bacteria and single-celled algae) suspended in water it pumps through its body. If those particles are themselves toxic, they can seriously discomfort, and occasionally kill, a human who eats a mollusc that has been feeding on them.

The most common culprits are algae called dinoflagellates and diatoms, several species of which make potent toxins. These algae often multiply into spectacular blooms along coastlines. Even in the absence of such a bloom, though, they can be abundant enough to cause problems. For this reason, in most places in the rich world at least, bivalves intended for sale have to be tested before they go to market. That involves taking samples to a laboratory, which is cumbersome and time-consuming. What is needed is a simple test that can be carried out on-board a ship. And Waqass Jawaid, of Queen’s University in Belfast, thinks he has one.

One way of screening shellfish is pretty crude. This is to inject a mouse with a sample and see if it gets ill— a procedure no longer used in Europe, but still permitted in parts of America. The alternative, a mix of chromatography and mass spectrometry, is more sensitive, but requires expensive equipment and trained staff. Dr Jawaid’s method, which he and his colleagues report in the Journal of Agricultural and Food Chemistry, employs antibodies to create a system similar to a pregnancy test.

Read the full story at The Economist