One problem is that fisheries often target what scientists call BOFFFFs: big, old, fat, fecund, female fish. Their large bodies are prized by fishers, but BOFFFFs are a vital source of new baby fish. Take these away and the size spectrum quickly veers out of kilter. One way to manage this is to encourage the fishing industry to target medium-size fish, allowing mature ones to replenish depleted populations.
Some scientists believe there may be too many whales for the population to sustain itself. Others say this explanation of “overcapacity” and “natural causes” overlooks the gantlet of hazards that grays now face — including ecosystem alteration, ship strikes, entanglement in fishing gear, plastics pollution, disease, ocean acidification and loss of kelp forests.
“We’re getting vision of this landscape scale collapse for the first time … arguably it’s a little bit worse than we expected because of the extent of the barreness and the distribution so far out to sea,” Frankham told Breakfast.
But as rising ocean temperatures threaten to make fishery closures routine, it will be even harder to count on crab for holiday meals—or livelihoods. Over the past decade, warming sea waters have produced harmful algal blooms that contaminate crab meat with domoic acid, a neurotoxin that can cause seizures, memory loss and other serious symptoms and has been blamed for poisoning and stranding scores of sea lions in California every year. State officials delayed three out of the last six crab seasons to protect public health after an unprecedented multiyear marine heat wave, dubbed “the blob,” hit the north Pacific Ocean in 2013.
“The Southern Ocean is one of the most important yet least explored and understood regions of the planet when it comes to determining how global warming may affect the future of humanity, thanks to its capacity to absorb huge quantities of heat and carbon dioxide, and melt swaths of the Antarctic ice sheet.”
More than 90% of the heat trapped by carbon emissions is absorbed by the oceans, making their warmth an undeniable signal of the accelerating crisis. The researchers found the five hottest years in the oceans had occurred since 2015, and that the rate of heating since 1986 was eight times higher than that from 1960-85.
The phenomenon of a patch of abnormally warm water off the west coast of North America gained notoriety in 2014, when the first such “Blob” was spotted and given that name, after the horror movie creature that devoured everything in its path. That first Blob lasted years, from 2013 to 2016. It has been blamed for slicing some forage fish populations in half; starving seabirds; triggering a collapse in cod; shifting tuna as far north as Alaska; pushing whales into the path of crab fishing lines and ships; and allowing exotics, including glowing tropical sea pickles, to arrive in northern waters.
Scientists from a local nature reserve who examined the waters of the bay said 95% of sea life to the depth of 10 to 15 meters was dead.
“…many sedentary marine species — including snails, worms, and mussels — are actually being transported in the wrong direction”.