Ocean conditions improving for salmon and steelhead
March 21, 2019
Coastal waters are cooling and attracting higher value, more fat-rich food -- a good sign for salmon, steelhead and ocean predators, such as Orcas -- after several years of unusually warm conditions (2014 – 2016), when the warm water “blob” dominated coastal conditions, according to a report released last week by NOAA Fisheries.
However, ocean conditions are still mixed.
The good news is that copepods off Newport, Ore., are mostly of cool-water, lipid rich species; krill lengths off Northern California have increased, an indicator of available forage for salmon and other species; anchovy numbers are on the rise; and several indicators of juvenile and adult salmon survival increased slightly off the Northwest Coast, especially for coho salmon, which are expected this year at average numbers after several years of low returns, according to the report.
The less than good news is there was still some evidence of unfavorable conditions during 2018: There is warmer than average subsurface water in the southern portion of the California Current; there is strong hypoxia (lack of oxygen) on the shelf in the northern areas; and pyrosomes (sea cucumbers) that moved north in high numbers during The Blob remain abundant in the northern and central waters.
Although the report forecasts low returns of chinook salmon to the Columbia River in 2019 (these are the last survivors that entered the ocean during the warm years and are now returning to the basin to spawn), there is a potential for higher returns in coming years as salmon in the ocean are now benefitting from the improved conditions.
Researchers found some of the highest numbers of juvenile coho they had ever seen off the coast, following the steep decline in marine temperatures in 2014 – 2017, leading to, perhaps, better future coho runs. Juvenile chinook salmon catches were near normal, according to the report.
“We’re coming off of some really bad conditions and returning to more normal conditions,” Dr. Toby Garfield, director of the Environmental Research Division at the Southwest Fisheries Science Center, and co-editor of the report, said on an informational conference Friday. “Although there is this potential to return to more normal conditions, we’re concerned that a change back to warmer conditions could occur sooner than would allow for species recovery.”