State biologists are forecasting a Southeast Alaska 2020 pink salmon harvest in the weak range, with a probability of 12 million fish, in a range of 7 million to 19 million humpies.
The harvest forecast of 12 million humpies is approximately one-third of the recent 10-year average harvest of 35 million pink salmon, according to the Alaska Department of Fish and Game report. A harvest near this forecast would also be about 60 percent of the average even year harvest since 2006.
The impact of warm sea surface temperatures on survival of pink salmon who went to sea in 2019 is unknown, adding uncertainty to the forecast.
Given very poor pink salmon escapements throughout northern Southeast Alaska in the parent year, 2019, the low abundance on juvenile pink salmon was not unexpected, perhaps because of less than optimal spawning conditions, biologists said.
The escapement and harvest of pink salmon in the Northern Southeast Inside subregion have been very poor since 2012 and the 2020 forecast indicates that such a pattern likely will continue. While pink salmon escapement goals for the Southern Southeast and Northern Southeast Outside subregions were met in 2018, harvests were well below average. Biologists also concluded that the low juvenile abundance index in 2019 may indicate that brood year 2018 pink salmon experienced poor freshwater and/or early marine survival.
Biologists said drought conditions in Southeast Alaska from the parent year 2018 spawn through spring of 2019 possibly had a negative impact on spawning or survival of overwintering juvenile salmon, but exact reasons for the low numbers of juvenile pinks are unknown.
Still juvenile humpies caught in the 2019 SECM survey trawls were among the largest in length in the 23-year survey and in good condition, indicating favorable nearshore marine conditions in the spring. Biologists also noted that the size of the juvenile pinks was similar to the large size of juveniles seen during the marine heat wave of 2014-2016 and that returns from those juvenile years were all below average.
The potential source of uncertainty of the 2020 pink salmon return is the anomalously warm sea surface temperatures in the Gulf of Alaska in 2019. Those warm temperatures persisted in the Gulf of Alaska from the fall of 2013 through much of 2016 and returned in 2018 and strengthened in 2019, the report said.
Sea surface temperatures in the entire Gulf were well above average during that time period. Pink salmon that went to sea from 2014 to 2018 returned in numbers below expectation and below recent odd-and-even-year averages.
The ADF&G forecast is based primarily on juvenile pink salmon abundance information collected by the agency’s Southeast Alaska Coastal Monitoring (SECM) project in northern inside waters of Southeast Alaska. The project was initiated in 1997 to improve understanding of effects of climate and nearshore ocean conditions on year class strength of salmon and ecologically related species.
Data is collected from systematic surveys conducted annually in June and July in upper Chatham and Icy Strait and are highly correlated with the harvest of adult pink salmon in the following year. In 2019 the juvenile pink salmon abundance catch per unit of effort was the third lowest in the 23 years of SECM surveys.
