Commercial harvesters in Prince William Sound caught nearly 56 million salmon in 2019, including 47.4 million humpies, despite climate changes that promoted NOAA Fisheries to note waters were warm or warmer than The Blob years.
Preliminary harvest results posted by the Alaska Department of Fish and Game as of Oct. 2 showed a Prince William Sound harvest that also included 5.3 million chum, 2.6 million sockeye, 504,000 silver and 18,000 Chinook salmon.
Chinook and sockeye commercial harvests were above average and chums too were ahead of forecast, while the Copper River District experienced a weak catch of coho, said Jeremy Botz, gillnet area management biologist for ADF&G in Cordova.
The pink salmon harvest was also robust, but Charlie Russell, seine area management biologist for ADF&G in Cordova, noted the significance of pre-spawn mortality events due to drought conditions. Overall escapements were within the escapement goal ranges for most districts, but salmon were unable to enter many streams because of low flow conditions, Russell said.
Aerial surveys were done throughout the fishing season, but it is still uncertain whether escapements were met, he said. The brood year fish spawned in 2019 would leave in the spring of 2020 and return in 2021, at which point biologists will know the real effect of the drought year of 2019.
Drought conditions impacted all species of salmon not just in Prince William Sound, but statewide, causing widespread mortality events.
“It was a dry summer and the way climate conditions are continuing, this is more than likely to become more commonplace,” Russell said. “The hatcheries struggled as well to achieve brood stock goals. They had water issues at the hatcheries, which affected their ability to do egg takes. We did get enough rain early in September for them to continue their egg takes, but they missed egg take goals at Cannery Creek and Armin F. Koernig (hatcheries).”
The last times the Prince William Sound area had significant drought years were 1991 and 2004.
ADF&G manages fisheries using escapement-based management methods.
Recent reports from NOAA Fisheries note that as marine heat waves intensify, ecological changes are occurring. About five years ago a large marine heat wave that became known as “The Blob” hit the Pacific Ocean off the West Coast.
The results were stark, NOAA Fisheries biologists said. The event that started off the West Coast in 2014 was “completely off the chart,” said Andrew Leising, a research oceanographer at NOAA Fisheries’ Southwest Fisheries Science Center. It exceeded the extent of the strongest El Nino patterns, which commonly change weather throughout West Coast states over the last 30 years, NOAA Fisheries reported.
In 2015, the Blob heat wave enveloped the West Coast, elevating temperatures ashore and an El Nino developed. In 2016 West Coast waters cooled, but the Gulf of Alaska remained warm.
In 2017 cooling continued, but Arctic waters remained warm, the NOAA report said. In the North Pacific Ocean, climate change studies suggest that heat waves will become more common, cover larger areas, and last longer, the NOAA report said.