According to an analysis by the National Oceanic and Atmospheric Administration which has started monitoring ocean conditions, fish swimming in the sea over the past year have been fortunate enough to get some of the best water temperatures and abundance. of food along the West Coast over the past 24 years.
This could be good news for salmon and rainbow trout over the next several years, biologists said.
The receiving waters in 2021 appear to be the second most favorable for fish since NOAA scientists began monitoring ocean conditions, said Brian Burke, fisheries biologist for NOAA Fisheries.
âIt’s kind of that growing image of, ‘Wow, things are going really good right now in all areas,’ Burke said.
Ocean conditions in 2021 were battered by what Burke called a phenomenal year in 2008, after which researchers saw increased returns of salmon and rainbow trout for several years.
Researchers are measuring a variety of signs that constitute good ocean conditions, including sea surface temperature and the amount of food available to young salmon.
Last year, researchers observed a significant upwelling in winter and spring, which brought cold water from the depths of the ocean to the shoreline, creating perfect growing conditions for salmon and rainbow trout. rainbows that migrate to the sea, said Burke.
Upwelling has brought many nutrients from the deep sea to the surface, he said. The extra food helps the salmon to grow quickly. As young salmon get bigger, they escape the clutches of predators such as seabirds, he said.
âThe upwelling has created a really productive coastal system,â said Burke.
This productivity has grown slowly over several years, said Burke, after a series of difficult years for ocean fish.
A body of warm water known as the Blob hammered the west coast marine ecosystem, peaking in 2014 and 2015. The Blob left fewer food sources available for young salmon entering the ocean. The sea heatwave has also forced more predators to eat salmon. In addition, it caused the largest algae blooms harmful to crabs and clams on the west coast.
These marine heat waves are becoming more common, according to a NOAA press release regarding a 2019 hot body of water similar to the Blob.
The recent upwelling of cold water has been a welcome relief from the heat waves and will likely benefit the young salmon and rainbow trout that have traveled the ocean this year, Burke said.
However, nothing is guaranteed. For example, he said, predators could melt and take a bite of the growing salmon. NOAA’s ocean conditions assessment does not take predators into account.
On the flip side, beneficial ocean conditions also help a lot of anchovies, sardines and smelt, Burke said, which could give predators more species of fish to munch on.
Right now, said Burke, researchers are individually evaluating each sign of how hospitable the ocean is for fishing, when in fact the whole system is linked.
Eventually, he said he would like to design a way to look at the ecosystem in a more connected way, similar to a flowchart. In this kind of approach, he said, researchers could identify where a bottleneck could arise in the network of ocean conditions.
Additionally, Burke said he hopes an ecosystem-wide approach to monitoring ocean conditions could help fisheries beyond salmon management. For example, he said, commercial fishermen in Oregon could plan business moves years in advance.
âCommercial fishermen might know things like squid distribution in advance or even estimate squid distribution based on things like sea waves,â Burke said.