Wednesday, November 27, 2019

Southeast Alaska Pink Salmon Forecast Low

Alaska state biologists are forecasting a harvest of 12 million pink salmon in Southeast Alaska in 2020. It would represent one-third of the recent 10-year average harvest of 35 million fish, and 60 percent of the average even year harvest since 2006.

Pink salmon that went to sea between 2014 and 2018 returned in numbers below expectation and below recent odd-and-even-year averages. The impact of warm sea surface temperatures on survival of pink salmon that went to sea in 2019 remains unknown, adding uncertainty to the forecast.

The Alaska Department of Fish and Game (ADF&G) plans to manage the 2020 commercial purse seine fisheries in-season based on run strength, the agency said, in its forecast issued on Nov. 20.

The harvest forecast is based primarily on juvenile pink salmon abundance indices collected during the NOAA Alaska Fisheries Science Center’s Southeast Alaska Coastal Monitoring (SECM) project. The SECM project was initiated in 1997 to learn more about the impact of climate and nearshore ocean conditions on year class strength of salmon and ecologically related species.

Since 2018, the SECM project has been conducted cooperatively by NOAA and ADF&G, the agencies combining efforts to produce a joint pink salmon harvest forecast using SECM data.

State biologists said the low juvenile abundance index in 2019 was not unexpected. Pink salmon escapements in 2018, the parent year, were very poor throughout northern Southeast Alaska inside waters and the escapement goal was not met in that sub region, which may have resulted in below optimal egg deposition.

The forecast report notes that escapement and harvest of pink salmon in the Northern Southeast Inside sub region have been very poor since 2012 and the 2020 forecast indicates this pattern is likely to continue. Pink salmon escapement goals for the Southern Southeast and Northern Southeast Outside sub regions were met in 2018, but harvests were well below average. The low juvenile abundance index in 2019 may also indicate that brood year 2018 pink salmon had poor freshwater and/or early marine survival.

Biologists said it is possible that drought conditions in Southeast Alaska from the parent year 2018 spawn through the spring of 2019 reduced spawning success or negatively impacted overwinter survival of juvenile salmon, but exact reasons for the low juvenile abundance are unknown. Juvenile pinks caught during the 2019 SECM survey trawls were among the largest in length in the 23-year time series and were in good condition, indicating favorable nearshore marine conditions in the spring. The size of juvenile pinks was similar to the large size of juvenile seen during the marine heat wave of 2014-2016 and returns from those juvenile years were all below average.

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