SURVEY FINDS GOOD KRILL NUMBERS AGAIN OFF OREGON, BUT EVEN MORE PYROSOMES
Krill — hugely important near the base of the ocean food web — and young Dungeness crab numbers were as high as they’ve been in some time, but there are even more pyrosomes off Oregon’s Central Coast and to the south than last year.
RESEARCHERS CALLED THE RETURN OF KRILL TO THEIR SAMPLING NETS “A WELCOME SIGHT SINCE THESE IMPORTANT FORAGE HAVE LARGELY BEEN ABSENT OVER THE PAST COUPLE YEARS SINCE THE ANOMALOUS WARMING” FROM THE BLOB. (NWFSC)
Jennifer Fisher, fresh off a 10-day survey between San Francisco Bay and Newport, reported the findings on the Northwest Fisheries Science Center blog.
“These are the most Dungeness larvae and juveniles we’ve collected in a long time, and we have not seen krill numbers like this since before 2015,” Fisher followed up via email.
That year, 2015, was the height of The Blob — the huge pool of warmer than usual water in the Northeast Pacific that messed things up at sea and on land — and it was also a year after pyrosomes first began to be found in our coastal waters.
By last year, the tropical gelatinous, sea-pickle thingies that are actually colonies of organisms were clogging fishing gear off our coast and even turned up as far north as the rim of the Gulf of Alaska, also a first.
While rockfish were observed feeding on pyrosomes, it’s not clear how their numbers will affect the food web. Another NOAA blog from last October states, “At this point, there are more questions than answers.”
But the May survey answered the question whether they’re still out there.
“The pyrosome catches appear slightly larger and the colonies are larger compared to last year,” reports Fisher.
They can be found starting about 10 miles off the coast, living on the bottom during the day and rising to the surface at night.
PYROSOMES FILL A COOLER ABOARD THE NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION’S VESSEL, THE BELL M. SHIMADA. (NWFSC)
The Science Center will soon conduct another closely watched spring survey, collecting information on young Chinook and coho off Oregon.
Last year’s produced very low catches while one a couple years ago found very small fish. But the resurgence of krill is a hopeful sign that the food web could be rebuilding coming out of the hangover from the Blob.
Fisher also reported on Science Center’s blog that copepods are in a state of flux between winter warm-water communities and summer, cold-water ones that come with the upwelling.
So what does it all mean?
“The krill is a good sign, but the pyrosomes are not, since they are indicative of warm water,” she says. “And the transitional copepod community is also not a great sign for salmon. But it’s still early in the summer upwelling season, so things can certainly change.”
