Estero Bay, Pismo Beach are hotspots for shark bites on otters, study finds
Sea otters rest just inside the mouth of the Morro Bay harbor. JOE JOHNSTON — jjohnston@thetribunenews.com |Buy Photo
White sharks are taking a heavy toll on California’s sea otter population.A recent article for the journal Marine Mammal Science concluded that the Estero Bay and Pismo Beach areas are hotspots for shark bites on sea otters. The article written by four sea otter biologists noted an eightfold increase in shark bites along the sea otters’ southern range, which stretches from Cayucos to Point Conception.“Over the past 10 to 15 years the number of shark-bitten sea otters in California has increased with shark-related injuries becoming the most frequently identified primary cause of death in the assemblage of beach-cast carcasses,” the article concluded.White shark bites now are found on more than 50 percent of recovered otter carcasses, the study said.The trend is puzzling because sea otters are not considered a prey species for white sharks. The biologists concluded that the bites, while fatal, were exploratory only and the sharks did not intend to eat the otters.The trend is also troubling because it threatens to stop the recovery of sea otters in California, said Mike Harris, a sea otter biologist in Morro Bay with the state Department of Fish and Wildlife, who co-wrote the article.“It’s happening in the part of the otters’ range in the north and south where we need population growth,” he said. “Shark-bite mortality is essentially keeping the otter population from expanding into new habitat.”The trend shows no sign of letting up. On Monday, Harris recovered a shark-bitten sea otter carcass from Morro Strand State Beach, not far from where a shark bit a chunk out of a woman’s surfboard on Saturday.California sea otters range from Pigeon Point south of San Francisco in the north to Point Conception in the south. A census in 2014 put the otter population at 2,944, up five animals from the previous year.Sea otters are making a slow recovery after being hunted to near extinction for their luxurious fur during the 18th and 19th centuries. A small colony survived in Big Sur.In addition to shark bites, sea otters suffer from many other causes of death, including microbial toxins from polluted runoff and brain infections contracted from the feces of wild and domestic cats.The animals have been listed since 1977 as threatened under the federal Endangered Species Act. Their population would have to exceed 3,090 for three consecutive years to have them removed from the list.In the heart of their range, from Monterey to Cayucos, the otter population is stable and at the carrying capacity of their habitat. However, otter populations in the southern extent of their range have dropped by 3.3 percent in the past five years, according to the U.S. Geological Survey, which conducts an annual sea otter population count.The cause of this increased shark-bite mortality is unclear, Harris said. The most common explanation is that the population of white sharks is increasing, although there is little data to corroborate that.White sharks have been fully protected in California since 1994. The sharks feed primarily on seals, which are thriving. Northern elephant seals, sea lions and harbor seals have all experienced population increases in recent decades.“Their main prey base is very robust and growing,” Harris said.A 2014 study put the shark population at 2,400.The authors of the article studied the reports on 1,870 otter carcasses collected since 1985. A sharp increase in shark bites on otters began in 2003.
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Climate change will irreversibly force key ocean bacteria into overdrive
Amped-up bacteria
By breeding hundreds of generations of the bacteria over the course of nearly five years in high-carbon dioxide ocean conditions predicted for the year 2100, researchers found that increased ocean acidification evolved Tricho to work harder, producing 50 percent more nitrogen, and grow faster.The problem is that these amped-up bacteria can’t turn it off even when they are placed in conditions with less carbon dioxide. Further, the adaptation can’t be reversed over time — something not seen before by evolutionary biologists, and worrisome to marine biologists, according to David Hutchins, lead author of the study.“Losing the ability to regulate your growth rate is not a healthy thing,” said Hutchins, professor at the USC Dornsife College of Letters, Arts and Sciences. “The last thing you want is to be stuck with these high growth rates when there aren’t enough nutrients to go around. It’s a losing strategy in the struggle to survive.”Tricho needs phosphorous and iron, which also exist in the ocean in limited supply. With no way to regulate its growth, the turbo-boosted Tricho could burn through all of its available nutrients too quickly and abruptly die off, which would be catastrophic for all other life forms in the ocean that need the nitrogen it would have produced to survive.Some models predict that increasing ocean acidification will exacerbate the problem of nutrient scarcity by increasing stratification of the ocean — locking key nutrients away from the organisms that need them to survive.
What the future may hold
Hutchins is collaborating with Eric bbb of USC Dornsife and Mak Saito of WHOI to gain a better understanding of what the future ocean will look like, as it continues to be shaped by climate change. They were shocked by the discovery of an evolutionary change that appears to be permanent — something Hutchins described as “unprecedented.”“Tricho has been studied for ages. Nobody expected that it could do something so bizarre,” he said. “The evolutionary biologists are interested in it just to study this as a basic evolutionary principle.”The team is now studying the DNA of Tricho to try to find out how and why the irreversible evolution occurs. Earlier this year, research led by Webb found that the organism’s DNA inexplicably contains elements that are usually only seen in higher life forms.“Our results in this and the aforementioned study are truly surprising. Furthermore, they are giving us an improved view of how global climate change will impact Trichodesmium and the vital supplies of new nitrogen it provides to the rest of the marine food web in the future.” Webb said.The research appears in Nature Communications on Sept. 1.Hutchins, Webb and Saito collaborated with Nathan Walworth, Jasmine Gale and Fei-Xue Fu of USC; and Dawn Moran and Matthew McIlvin of WHOI. The work was funded by the National Science Foundation (grants OCE 1260490, OCE 1143760, OCE 1260233 and OCE OA 1220484); and the G.B. Moore Foundation (grants 3782 and 3934).
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Monterey Bay National Marine Sanctuary counts its victories.
Nature shows so often follow the same script: The earth is amazing, but we humans are ruining it.Big Blue Live, a PBS/BBC production, flips that script. It toasts Monterey Bay as a conservation success, a case study of how science-based ocean management is allowing a highly degraded ocean habitat to rebound.That resilience will be on full, high-definition display when the show airs real-time footage of Monterey Bay sea life in the U.S. Aug. 31-Sept. 2.Monterey Bay National Marine Sanctuary (MBNMS), which is co-hosting with Monterey Bay Aquarium, is taking the occasion to count its victories since its 1992 designation, which brought with it a host of federal protections.The National Oceanic and Atmospheric Administration's latest status report on MBNMS includes some encouraging news, announced in a press release today. Among the highlights:- Populations of elephant seals, blue whales and gray whales are stable or increasing. The sanctuary now counts more than 30,000 resident elephant seals, which were once close to extinction. Humpback whale numbers have bounced back so well, the local sub-population is proposed for removal from the endangered species list.- Sea-floor habitats in and near the Davidson Seamount, an underwater mountain about 75 miles southwest of Monterey, are almost "pristine."- The kelp forests that shelter and feed many of Monterey Bay's marine creatures are "generally abundant and stable."- Abundant forage species are feeding both marine animals and people. Fishermen have landed more than a billion pounds of sardines, anchovies and squid since the sanctuary was designated 23 years ago. That includes a local squid harvest of 90 million pounds last year alone.- Brown pelicans made it off the federal endangered species list in 2009, rebounding from a low of less than 1,000 breeding pairs in the 1970s to almost 11,700 regional pairs in 2006.- Southern sea otters have bounced back from about 1,800 to 2,900 within the sanctuary since 1992. That's great for other kelp-forest species, since otters eat the sea urchins that mow down kelp.- Local beaches are cleaner, thanks to sewer system improvements and reduced stormwater runoff.The report, however, is not entirely rosy. Sewage spills and high coliform counts still occasionally pollute local beaches. Regulators are still finding contaminants in local waters. Marine animals are getting tangled in fishing gear and eating plastic litter, while sand mining continues to erode the Monterey Bay shoreline.And climate change continues to threaten the sea—especially ocean acidification, which happens when elevated CO2 levels from fossil fuel burning cause the ocean's pH to decline. That chemical shift is affecting the ability of some creatures to form or maintain their shells, which has ripple effects through the food web.The full report, according to NOAA, will be available online this fall.
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How Many Fish in the Sea? Genetic Testing Could Answer That
Advances in genetic testing have revolutionized everything from health care decisions to crime forensics. Now, the technology may help protect marine life off the California coast.In the waters of Monterey Bay, DNA sequencing is allowing biologists to study fish and whales without ever having seen them.Just a sample of seawater, the volume of a water bottle, is enough to reveal what marine life has been swimming through that part of the ocean. The technique could improve marine monitoring, where scientists track an ecosystem year after year to gauge how it’s doing.One Fish, Two FishTaking a marine census today requires hours of field time, either with scuba diving or boat trips.“It gets a little challenging because you’re floating, you’re swimming, you’re looking, you’re counting,” says diver Dan Abbott, unloading his scuba gear on a beach in Monterey.He’s holding a waterproof clipboard, on which he’s tallied all the fish and marine life he saw in a kelp forest just offshore.“About 150 fish in all. Pile perch, black perch, blue rockfish, kelp rockfish,” he says, just for a start. He’s diving with a team from Reef Check California, a group of volunteers that surveys this site twice a year.The group’s data help answer a question that’s key to California’s conservation efforts: are there more fish here now than there were eight years ago?That’s when this kelp forest became part of a massive experiment to restore marine life in California. It was set aside as a marine protected area, where there’s little or no fishing allowed.There are now more than a hundred protected areas up and down the coast, covering 16 percent of state waters. The idea is that marine life will slowly recover there, improving the ecosystem both inside and outside the boundaries of each area.The only way to know if these areas are working is through underwater surveys, repeated year after year. In 2013, biologists reported encouraging results in the protected areas off the Central Coast.Field surveys are expensive. The state supplied $16 million for monitoring studies, and the funding has already run out in some regions of the coast. Monitoring has continued, thanks to universities, foundations and volunteer groups.Studying the Ocean Without Getting Wet“It’s been amazing what we can detect in just a liter of seawater,” says Jesse Port, an environmental genomicist at the Center for Ocean Solutions at Stanford University.He points to a rack of one-liter Nalgene water bottles that he uses to take seawater samples from the kelp forests in Monterey Bay. The rest of the work happens in the lab with a technique known as “environmental DNA” or eDNA.“So all organisms shed their DNA,” he says. “Their skin, their scales, their waste – all of this gets into the water. You can think of it as a soup of genetic information.”Port filters the seawater to collect all the cells. Then, he weeds out the algae and plankton and sequences the DNA of all the vertebrates, like whales, seals, and fish.“We get, with the machine we’re using, 150 million sequence reads for a given sequence run,” he says, “and that’s a lot of information.”Those gigabytes of results require heavy data-crunching, but eventually, he ends up with a spreadsheet that tells him what organisms were found.The approach is possible because DNA sequencing has gotten so much cheaper. One sample costs just $1,500.“This was just not possible five, ten years ago,” Port says. “And sequencing technology is just going to get better, so this will probably get even cheaper.”Finding Turkey UnderwaterPort first ran DNA tests in one of the large tanks at the Monterey Bay Aquarium, which provided an easy test case because he knew exactly what was swimming there.But he got back results he didn’t quite believe. “Things like turkey,” he says. “We picked up chicken DNA in these tanks.”Turns out, poultry was in the feed some of the fish were getting. But it raised some big questions. How do you know whether the DNA comes from a fish or from something it ate miles away? Or how do you know the DNA didn’t float in on a current?Port is still working on the answers to these questions and he’s doing studies to ground truth his results, checking them against what scuba divers find. But if the technology proves itself in the ocean, it could revolutionize how marine monitoring is done.“You can cover such a larger area by taking water samples,” he says, “rather than having divers do that all themselves.”Paul Michel, the superintendent of the Monterey Bay National Marine Sanctuary, says they’re already using eDNA testing to help assess species diversity in the sanctuary.“Absolutely, we did DNA testing on a research cruise in May,” Michel says, “and at each stop on the way, we were taking water samples. We can compare the DNA results to other types of samples over time.”Eventually, it doesn’t even have to be humans taking those water samples.
DNA Lab at Sea“What this is, is a microbiology lab that exists out in the ocean,” says Jim Birch of the Monterey Bay Aquarium Research Institute, pointing to a 10-foot yellow tube. It’s called a long-range AUV, or autonomous underwater vehicle.It looks like a torpedo, but it’s actually a robot, containing a miniature DNA lab called an Environmental Sample Processor.The robot cruises along underwater, taking samples and analyzing them onboard. Birch recently sent it out for a test run in Monterey Bay.“I was sitting in my living room with my computer open and there in front of me was the control panel for the AUV,” he says. “And I could direct it to go to a new place and it was just this surreal feeling.”When the AUV finds an organism it’s looking for, it surfaces and calls home, pinging a satellite or cell phone network with the data, and giving scientists an almost real-time snapshot of the ocean.Currently, it only tests for one thing at a time, like algae or plankton, and Birch says there’s more engineering work to be done before the AUV gains widespread use.“This is going to be transformative in oceanography,” he says. “You don’t have to be out there on a boat with a huge crew, spending all this money.”
A change that could help the state’s conservation funding go farther, ensuring California’s marine protected areas are working.
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NASA: Rising Seas About to Catch Up With the West Coast
NASA Animation shows the wide variance in sea level rise in recent years. The pale coloration along the West Coast illustrates a lower rate of rise. (NASA Scientific Visualization Studio)
Rising Seas are about to become a bigger issue for the West Coast, according to scientists.Using satellite and other data, NASA scientists have been tracking rising sea levels around the world. They say that natural cycles in the Pacific have been masking effects of sea rise for about the last 20 years. But that’s changing.“In the next five or ten years, I think the west coast of the United States is going to catch up,” says Josh Willis, a climate scientist at NASA’s Jet Propulsion Lab in Pasadena. He says a major ocean phase known as the Pacific Decadal Oscillation is in the midst of a big shift.For about the past two decades, the PDO, which Willis describes as “El Niño’s bigger, slower, brother,” was “piling up” warmer water on the far side of the ocean, exacerbating sea rise there. When water warms, it expands.“So we’ve actually seen a slight drop in sea levels off of our coastline because of the rearrangement of heat within the oceans,” Willis explains.That rearrangement could mean an acceleration in the rate that seas rise long the West Coast, eventually overtaking the pace of sea level rise on the East Coast and elsewhere.“We could be looking at rates in the eastern Pacific two or three times as high as the global rates in the coming years,” says Willis. “So we could be in for wild ride over the next 20 years or so.”As KQED and San Francisco Public Press have reported recently, billions in shoreline development in the Bay Area are in the planning stages or already begun, despite scientists’ warnings about rising seas.Scientists say the brewing El Niño will also pile up warm water along California, making coastal flooding that much more likely, very soon. The warm water along the Equator that largely defines El Niño is expected to rival or surpass the legendary “Godzilla” El Niño of 1997-98 in strength.NASA says global sea levels have risen about eight inches since the beginning of the 20th century and more than two inches in the last 20 years. Though simple thermal expansion of the water accounts for about a third of the rise so far, climate scientists expect melting glaciers and ice sheets to play a much larger role in coming years.
Video: https://youtu.be/rkCzae-FCek
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A Giant Glob of Deadly Algae Is Floating off the West Coast
From the air, the Pacific algal bloom doesn't look like much of a threat: a wispy, brownish stream, snaking up along the West Coast. But it's causing amnesia in birds, deadly seizures in sea lions, and a crippling decline in the West Coast shellfish industry. Here's what you need to know about it, from what this bloom has to do with the drought to why these toxins could be a real threat to the homeless.What's causing it? The culprits are single-celled, plant-like organisms called pseudo-nitzschia, a subset of the thousands of species of algae that produce more than 50 percent of the world's oxygen through photosynthesis. They're a hardy variety usually found in cool, shallow oceans, where they survive on light and dissolved nutrients, including silcates, nitrates, and phosphates. "They're sort of like the dandelions of the sea," says Vera Trainer, who manages the Marine Biotoxin Program at the Northwest Fisheries Science Center in Seattle. "They're always there in some low numbers, just waiting for nutrients to be resupplied to the ocean's surface." In most years, blooms in the eastern Pacific are contained near "hot spots" that dot the West Coast—relatively shallow and sheltered places like California's Monterey Bay or the Channel Islands. They usually flare up in April or May as trade winds cycle nutrient-rich waters from offshore depths to the coast in a process called "upwelling," but they fade after only a few weeks.Why is it sticking around so long? The jury's still out, but scientists are beginning to get a clearer idea. These past few years have been "incredibly weird" in the northeast Pacific, says Nate Mantua, a research scientist at the National Oceanic and Atmospheric Administration's Southwest Fisheries Science Center in Santa Cruz. He points to the same "ridiculously resilient ridge" of high pressure that's been causing the historic drought in the western United States: This pressure also resulted in a pool of exceptionally warm water in the Pacific (known as "the blob"), with little weather to disperse it. Those conditions, along with prevailing winds and colder currents that ferry nutrients back to the coast, seem to be supplying the algae with a seemingly endless feast.That makes the source of this bloom different from its cousin in the Gulf of Mexico, where fertilizers flowing from as far as Iowa are feeding a zone of algae that's as large as New Jersey. "We're seeing them in relatively pristine waters of the US West Coast," Trainer explains, though she adds runoff and sewage discharge may be playing some role in the blooms off Southern California.So just how big is this thing? Bigger than researchers have ever seen: a patchy stream that stretches from Southern California up along the Alaskan coast. The hot spot blooms that appear each spring are merging for the first time, Trainer explains. Though the combined mass has ebbed and flowed over the past four months, it hasn't let up; her team finds algae each time they journey out to sea, with no signs of abatement soon. And it's also unusually potent. "These are the highest levels of toxicity we've ever seen," says Raphael Kudela, a professor of ocean sciences at the University of California-Santa Cruz. "It's a truly extraordinary phenomenon."
Video: https://www.youtube.com/watch?v=SiAFmxq0VOU&feature=youtu.be
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Toxic Algae Is Killing Sea Lions, Shows No Sign of Diminishing
Cells of the microalgae that make the neurotoxin domoic acid. (Anthony Odell/University of Washington)
A toxic algae bloom that began off the West Coast this spring now stretches from California to Alaska. It’s poisoning marine life from shellfish to sardines to sea lions, and scientists say it’s one of the worst they’ve seen.“We’ve never seen a bloom this big before,” says Anthony Odell, a research analyst with the University of Washington’s harmful algae bloom monitoring program. “It’s also one of the most toxic blooms we’ve seen.”Odell is one of a rotating team of scientists who are studying the bloom aboard the Bell M. Shimada, a research vessel belonging to NOAA, the National Oceanic and Atmospheric Administration. Equipped with state-of-the-art technology, the ship is traveling this summer up the west coast to British Columbia.Odell says he’s seen a lot of toxic blooms, but this one’s different, partly because it consists of several species of harmful algae.“It’s making a toxic plankton soup,” he says. “It’s pretty amazing to see all these things blooming together, because usually they prefer these different conditions so there’s definitely something unusual going on.”Toxic algae blooms are not uncommon in the Pacific Ocean—they’re called red tides and they come in summer’s warm waters and dissipate in the fall. But the current algae bloom isn’t likely to dissipate.The algae are thriving in unusually warm waters—in fact, abnormally warm water that scientists are calling “the Blob.” The algae bloom itself is an estimated 40 miles wide and, in some places, could reach a depth of more than two football fields, according to sonar readings. Scientists have been able to verify the presence of the algae bloom down to 45 feet by testing the water.“From a scientific standpoint it’s fascinating,” Odell says. “From a sea life and human health view point, it’s pretty scary. Because it’s so big and it’s so toxic and it’s not really giving sea life a chance.”
One of the toxins the algae are producing is domoic acid. It’s a neurotoxin that doesn’t have negative effects on shellfish and fish. But it can kill other marine life because the micro algae—or phytoplankton—are the base of the food web.“Everything in the ocean eats phytoplankton or eats something that eats phytoplankton,” Odell says. “So when you have one of these species that starts producing toxin, it works its way up through the food chain really fast. It gets into shellfish, it gets into crabs, it gets into small fin fish like sardines and anchovies, which are then fed on by salmon and pelicans and seals and sea lions.”NOAA scientists say domoic acid from the algae bloom is responsible for the high number of seizures and deaths in California sea lions this summer.Domoic acid can also poison humans, causing nausea and dizziness, or in worse cases, permanent short-term memory loss, and even death. That’s why fishery managers have shut down some crab fisheries in Oregon and Washington, and severely restricted fishery markets from California’s central coast.“We’re now unable to market anchovy,” says Diane Pleschner-Steele, executive director of the California Wetfish Producers Association. “And there’s a small, kind of an ethnic market for anchovy for human consumption. And also, anchovy used for bait and for animal food. So we’re now prohibited from selling to the public.”
She said after the anchovy market collapsed, fishermen moved on to squid, which feed on a different plankton.
So far, there’s little sign the algae bloom is going to slow down and give sea life a break.“There’s still quite a bit of toxin production going on,” Odell says, “and a rather sizable bloom.”Although the unusually warm ocean water is one suspect, scientists still don’t know for sure the cause of the algae bloom. Odell says they’re researching whether climate change is contributing.“There’s been an international consensus that climate change would affect harmful algal blooms in the fact that we would likely see more of them,” Odell says. “But there’s just not enough data to tie the two together yet.”Scientists are scheduled to arrive in British Columbia in September. Then, it could take a few months to compile data before they can say more about what’s causing the toxic algae bloom, and what it means for the changing ecosystem of the Pacific Ocean.
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