2020 southeast alaska pink salmon harvest...
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2020 Southeast Alaska Pink Salmon Harvest Forecast
NOAA: Jim Murphy, Emily Fergusson,
Charlie Waters, Andrew GrayAlaska Fisheries Science Center
Auke Bay Laboratories
Deccember 3, 2019
ADF&G: Andy Piston, Steve Heinl, Sara
Miller, and Rich Brenner
2019 Purse Seine Task Force Meeting
Sitka, AK
Alaska Department of Fish and Game
Southeast Alaska Coastal Monitoring Research
Alaska Department of Fish and Game
• Surveys are now being conducted on ADF&G Research
Vessel Medeia.
• Increased cooperation between NOAA and ADF&G;
continued efforts to increase the value of information for the
fishing industry.
Photo by master photographer Jim Murphy
Southeast Alaska Coastal Monitoring Research
Alaska Department of Fish and Game
Paradigm of pink salmon biology:
Mortality during early marine life is high, variable, and a major determinant of year class strength
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Days at sea
Perc
ent surv
ivin
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Mortality rates
(Parker 1968, Karpenko 1998)
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200Inshore Strait Coastal
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02468
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Jun Jul Aug
Month
Cat
ch p
er H
aul
Pink Salmon
Chum Salmon
Sockeye Salmon
Coho Salmon
Chinook Salmon
Surface Trawl Catch per Haul for Juvenile Salmon by Month
Alaska Department of Fish and Game
Icy Strait Hatchery Chum Salmon Origin
(thermal mark recoveries 1997-2016)
June July August
Alaska Department of Fish and Game
Pink Salmon Harvest Forecast Model Structure
• Peak surface trawl catch rates (CPUE) in June or July.
• Icy Strait Temperature Index (ISTI)
8Alaska Department of Fish and Game
Forecast Model Considerations• There are several ways that temperature (ISTI) could be
important to the forecast model.
• Survival: reduced survival during warm years. Since
growth is higher in warm years, this would imply that small
fish have better survival.
• Migration: Increased movement of SEAK stocks through
Icy Strait during warm years.
Length of Juvenile Pink Salmon
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1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 2017 2019
Fis
h L
ength
(m
m)
Peak CPUE (calibrated) of juvenile Pink Salmon
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Pea
k C
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E
Icy Strait Temperature Index (ISTI)
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Icy
Str
ait
Tem
per
atur
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dex
(⁰C
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Southeast Alaska Pink Salmon Harvest Forecast Model
(Calibrated CPUE + ISTI)
Southeast Alaska Pink Salmon Harvest Forecast Model Performance
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2004 2006 2008 2010 2012 2014 2016 2018 2020
SE
AK
pin
k s
alm
on h
arves
t (m
illi
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Adult harvest year
Harvest Forecast
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Southeast Alaska Drought
Photo by Dave Harris
Photo by Dave Harris
North Pacific Sea Surface Temperature Anomalies
2015 2019
2020 SECM Pink Salmon Forecast Summary
• The 2020 Southeast Alaska pink salmon harvest forecast is:
• 12 million (80% CI = 7 – 19 million).
• The forecast is based on a juvenile abundance index and temperature
(ISTI). The significance of temperature is unclear, it could be due to
variation in survival and/or migration of juveniles.
• Blob reformed in summer of 2018; significant drought throughout Southeast
Alaska in 2018 and 2019.
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