On Might 7, Patrick Robinson took a ship out to Año Nuevo Island to survey the ocean lions that come to start on this rocky outcropping north of Monterey Bay.
The shore was suffering from useless pups — infants that appeared as if they’d been delivered too early and due to this fact have been too weak and small to nurse, or had been useless at start.
Comparable observations have been being made additional down the coast on San Miguel Island within the Channel Islands — the place large colonies of sea lions collect yearly — and as far south as Mexico.
Robinson, the director of UC Santa Cruz’s Año Nuevo Reserve, stated it’s commonplace to see some useless pups this time of 12 months. He stated sick or malnourished females often cease on their approach south to abort. However the numbers he was seeing have been alarming. And with the height of birthing season nonetheless a number of weeks away, it augurs a doubtlessly critical and worrisome state of affairs.
Stranding coordinators and biologists up and down the California coast say there’s clearly one thing happening, however they nonetheless don’t know what.
Exams for chicken flu — which has obliterated populations of sea lions and elephant seals in South America — are being processed. So, too, are exams for domoic acid, which has poisoned massive numbers of sea lions up to now, in addition to different widespread pathogens.
“In a typical 12 months, one would possibly count on to see 5 to 10,” useless pups, stated Megan Moriarty, a veterinarian at UC Santa Cruz. “However we’ve now counted 250 to 300 useless sea lion pups” on Año Nuevo Island.
She stated observations included useless or stillborn pups, aborted fetuses, malnourished pups, and grownup females with dystocia — tough births — who’re additionally skinny.
“Sadly, widespread untimely useless pups have additionally been reported within the Channel Islands (San Miguel), which is an important nursery space for California sea lions,” she stated. “The trigger and impression of those mortalities stays unknown.”
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She and Sharon Melin, a analysis biologist with the Nationwide Oceanic and Atmospheric Administration’s Alaska Fisheries Science Middle, stated there are lots of potential causes for widespread sea lion pup mortalities, together with environmental components, corresponding to malnourishment, lack of obtainable meals associated to El Niño, infectious causes (micro organism, viruses corresponding to leptospirosis, influenza, brucella, coxiella, and others), and toxins (corresponding to domoic acid).
And though they each assume testing for chicken flu is warranted — contemplating it’s a multi-species international outbreak — “we’ve not noticed neurologic or respiratory indicators within the sea lions at Año Nuevo,” Moriarty stated.
“Reproductive failures and stillborn animals haven’t been a typical discovering with influenza A infections in marine mammals globally,” she stated.
Melin stated about 25,000 pups are born within the Channel Islands yearly.
“In some years — significantly in El Niño years, or typically heatwave years or different oddities that go on within the setting — we’ll have one thing like 20% to 30% untimely pups,” she stated.
She stated the pups born this time of 12 months are sometimes not “totally baked.”
“They may simply keep in a bit bit longer … and possibly should you may put them in an incubator and care for them, they could survive,” she stated.
And when necropsies are executed on these tiny pups, “you’ll see that the very last item to develop totally are their lungs. … In order that they’re simply not fairly totally developed sufficient to breathe on their very own and to achieve success. They’ll typically stay for a pair days at this level, however can’t nurse and don’t have the motor abilities to carry their head up or nurse successfully.”
She stated the moms will normally attempt onerous to get the pups to nurse, “they don’t know what’s happening, and so they’re making an attempt to determine why they’re not nursing. So there’s type of a whole lot of interplay that goes on there, however normally the pup will simply find yourself dying after a brief time frame.”
Michael Milstein, a spokesperson for the Nationwide Oceanic and Atmospheric Administration, stated the newest fisheries survey discovered “appreciable declines in anchovy off the south half of the state, the place a lot of the strandings are.”
He stated observations of predators and seabirds have been extra scattered, “suggesting they’re monitoring extra dispersed prey.” He stated surveys farther north haven’t but been accomplished.
However excessive numbers of brown pelican deaths, and main declines in California’s chinook salmon populations, have many involved about broader ecosystem troubles.
This 12 months, fishery managers determined to ban salmon fishing alongside the coast and in rivers for a second straight 12 months, looking for to assist chinook shares recuperate.
Stranding coordinators and biologists say the excellent news is that the California sea lion inhabitants is wholesome and sturdy; nonetheless, rescue facilities are filling up with sick and malnourished pups.
