Peter Fimrite & Kurtis Alexander, SAN FRANCISCO CHRONICLE
The poisoning of Dungeness crab off the California coast by a mysterious algae bloom may be bad news for the seafood industry, but to marine biologists and climate scientists, it is a frightening omen of future distress to a vibrant ecosystem.
Experts say the toxin in the algae, which likely flourished in this year’s record-high ocean temperatures, is one symptom of a wholesale shift in the physical and biological makeup of the Pacific Ocean — a transformation so abrupt and merciless that it is endangering species and forcing migrations before our eyes.
“We are talking about a whole ecosystem change — including a lot of changes besides just the blooms,” said Raphael Kudela, a professor of ocean sciences at UC Santa Cruz. “It’s really restructuring the way California looks.”
Tissue samples of Dungeness and rock crabs last week showed contamination by domoic acid, a neurotoxin known to cause seizures, coma and even death when consumed by animals or humans. The finding prompted California wildlife officials to delay the $60 million commercial crab season, which was supposed to start Nov. 15.
The poisonous algae, multiplying since April, is now estimated to be 40 miles wide, in some places reaching down as far as two football fields, marine biologists say. It is the biggest and most toxic bloom researchers have ever seen.
Read more at: Toxin in crab among impacts of warm sea that alarm scientists – San Francisco Chronicle
A world-first global analysis of marine responses to climbing human carbon dioxide emissions has painted a grim picture of future fisheries and ocean ecosystems.
University of Adelaide, Australia
Published October 12 in the journal Proceedings of the National Academy of Sciences (PNAS), marine ecologists from the University of Adelaide say the expected ocean acidification and warming is likely to produce a reduction in diversity and numbers of various key species that underpin marine ecosystems around the world.
“This ‘simplification’ of our oceans will have profound consequences for our current way of life, particularly for coastal populations and those that rely on oceans for food and trade,” says Associate Professor Ivan Nagelkerken, Australian Research Council (ARC) Future Fellow with the University’s Environment Institute.
Associate Professor Nagelkerken and fellow University of Adelaide marine ecologist Professor Sean Connell have conducted a ‘meta-analysis’ of the data from 632 published experiments covering tropical to artic waters, and a range of ecosystems from coral reefs, through kelp forests to open oceans.
“We know relatively little about how climate change will affect the marine environment,” says Professor Connell. “Until now, there has been almost total reliance on qualitative reviews and perspectives of potential global change. Where quantitative assessments exist, they typically focus on single stressors, single ecosystems or single species.
“This analysis combines the results of all these experiments to study the combined effects of multiple stressors on whole communities, including species interactions and different measures of responses to climate change.”
The researchers found that there would be “limited scope” for acclimation to warmer waters and acidification. Very few species will escape the negative effects of increasing CO2, with an expected large reduction in species diversity and abundance across the globe. One exception will be microorganisms, which are expected to increase in number and diversity.
From a total food web point of view, primary production from the smallest plankton is expected to increase in the warmer waters but this often doesn’t translate into secondary production (the zooplankton and smaller fish) which shows decreased productivity under ocean acidification.
“With higher metabolic rates in the warmer water, and therefore a greater demand for food, there is a mismatch with less food available for carnivores ─ the bigger fish that fisheries industries are based around,” says Associate Professor Nagelkerken. “There will be a species collapse from the top of the food chain down.”
The analysis also showed that with warmer waters or increased acidification or both, there would be deleterious impacts on habitat-forming species for example coral, oysters and mussels. Any slight change in the health of habitats would have a broad impact on a wide range of species these reefs harbour.
Another finding was that acidification would lead to a decline in dimethylsulfide gas (DMS) production by ocean plankton which helps cloud formation and therefore in controlling Earth’s heat exchange.
Source: Global marine analysis suggests food chain collapse — ScienceDaily
Kathleen Willett, NORTH BAY BOHEMIAN
Walking Sonoma and Marin county beaches recently has yielded some unusual sights and smells.
According to officials at the National Oceanic and Atmospheric Administration (NOAA), 12 dead whales have washed up on Northern California beaches in the last three months, including two along the Sonoma County coast and one in Marin County. The carcass of a young gray whale showed up on Portuguese Beach on May 23, with another gray whale washing ashore near Jenner around May 28. In Marin, a headless whale came ashore on South Beach along the Point Reyes National Seashore on May 26.
Other than the fact that they are all whales, what do the carcasses share in common?
“There is no unifying factor,” says Mary Jane Schramm, spokeswoman for the Gulf of the Farallones National Marine Sanctuary.
Marine scientists have identified four species among the dozen dead whales: orca, humpback, sperm and gray, which are commonly seen heading north along the coast this time of year. Their ages, along with their causes of death, have varied.
According to Schramm, one of the dead whales found in Pacifica was mature and possibly died of “old age,” given the condition and apparent wear on various body parts. Several others were young, possibly calves from the winter birthing season in Mexico, and may have been victims of predation by orcas.
One humpback was a victim of shipping traffic, while other whale carcasses have shown signs of possible “fishery interactions” such as net entanglements, which can mortally wound the immense animals.
In a typical year, one or two gray whale carcasses wash ashore. So what is different this year?
Read more at: Whale Mystery | News | North Bay Bohemian
Paul Shively, THE PEW CHARITABLE TRUSTS
The population of Pacific sardines, a crucial forage fish for marine life along the U.S. West Coast, has dwindled to the point that it can no longer sustain a commercial fishery, according to a preliminary assessment by scientists advising West Coast fishery managers.
The ongoing collapse is bad news for ocean wildlife, as well as fishermen and others who rely on a healthy ocean.
This is a major cause for concern, but it shouldn’t come as a complete surprise. In 2012, two government scientists predicted we would end up in exactly this position, finding a parallel with the last major collapse in the middle of the 20th century. Three years ago, the scientists wrote that “all indicators show that the northern sardine stock off the west coast of North America is declining steeply again and that imminent collapse is likely.
”That prediction turned out to be right.
A panel of scientists advising the Pacific Fishery Management Council is reviewing the draft assessment today, March 6, in Vancouver, Washington. In April, the scientists will make a recommendation to the full council, which has already established plans for an automatic cutoff of commercial fishing for sardines when the population’s biomass estimate falls below 150,000 metric tons. In recent years, the stock size has fallen steadily, from 1.4 million metric tons in 2007 to 300,000 metric tons in the last official stock assessment in August of 2014.
Now, the new draft assessment projects that the population will be less than 150,000 metric tons as of July 1, the beginning of the new fishing season.
Sardines are small individually, but they are a big deal for the ocean food web. They form large schools known as bait balls that provide an oil-rich source of protein for many species of seabirds, marine mammals, and bigger fish, including salmon and tuna. The estimated size of the West Coast sardine population has fluctuated from several million tons— based on sediment records gathered on the seabed off Southern California—to less than 5,000 tons in the 1960s following the last major collapse.
If the new assessment holds up to scientific review, fishery managers should follow through in April on their harvest guideline protocols and suspend fishing on sardines for the 2015 season. Doing so would give the population a chance to recover as ocean conditions improve.
Read more at: Bad News on the West Coast: Pacific Sardines Are Collapsing
Mary Callahan, THE PRESS DEMOCRAT
An intensifying spate of sea lion strandings on the California coast is likely caused by a shift in winds that has warmed coastal waters, making prey scarce for sea lion mothers and interfering with their ability to feed their pups, federal scientists said Wednesday.
The announcement marked the clearest answer yet to what might be affecting the sea lions, hundreds of which have come ashore malnourished and severely underweight in recent months.
With more than 940 animals, mostly pups, already admitted to rehabilitative care over the past several weeks, the state’s marine mammal centers are nearing capacity and running through resources, said Justin Viezbicke, California Stranding Network Coordinator for the National Oceanic and Atmospheric Association.
Many sea lions won’t be saved.
Read more via Scientists: Warm waters, scarce prey likely cause of | The Press Democrat.