Executive Summary of Recent Trends in the Eastern Bering Sea (pdf)
This section provides highlights and links to full contributions contained in this Report. The links are organized within four sections: Noteworthy, Physical and Environmental Trends, Ecosystem Trends, and Fishing and Human Dimensions Trends.
• In May 2019, elevated numbers of gray whale strandings prompted NOAA to declare an Unusual Mortality Event (UME). From January 1 through October 14, 2019, a total of 213 gray whale strandings were reported with 49 in Alaskan waters (p. 26).
• In spring and summer of 2018 and 2019, 282 ice seal carcasses (primarily young) were reported from the Bering and Chukchi seas prompting NOAA to declare an Unusual Mortality Event (p. 28).
• Northern fur seal population decline at St. Paul Island may be attributed to low pup growth rates due, in part, to extended foraging trips required for nursing females to provision pups (p. 30).
Physical and Environmental Trends
• The Bering Sea experienced a second winter of very reduced sea ice due to (1) residual heat in the Chukchi in fall of 2018 and (2) anomalous winds from the south in February 2019 causing ice retreat (p. 35, 36).
• The development of a weak/moderate El Niño event occurred in 2018 and persisted into 2019, but its future state is highly uncertain. The significantly positive PDO indicates warmer than normal SST along the west coast of North America and cooler than normal in the central and western North Pacific in spring 2019 (p. 40).
• Seasonal projections of SST from the National Multi-Model Ensemble (NMME) indicate continuation of warm conditions across virtually all of the North Pacific for October-December 2019. However, a reduction in magnitude of the positive anomalies is forecast for the southern Bering Sea shelf (p. 41).
• The 2018-2019 daily mean sea ice extent was the second lowest of record (only 2017-2018 was lower) (p. 44).
• The mean daily sea ice extent for the months October 15-December 15 show variability but a strong negative trend over the past 40 years. The mean early season sea ice extent for 2018-2019 was the lowest of record (p. 44).
• The cold pool extent for summer 2019 was reduced and retracted over the northwest portion of the survey area, reflecting low sea ice extent over the shelf during the winter 2018/2019 (p. 46).
• During the early 2000s warm stanza, much of the warmth was driven by conditions in March-May (southern shelf only) and in June-August (southern and northern shelves). The recent warm years have been warmer than average throughout the year (p. 52).
• Summer surface and bottom temperatures over the shelf increased from 2018 and were significantly warmer than the long-term mean. Unprecedentedly warm bottom temperatures occurred over the inner domain (p. 55).
• The 2019 OSCURS springtime drift pattern indicates unfavorable recruitment success for winter- spawning flatfish due to consistent westerly drift during spring (1 April-30 June) (p. 63).
• The timing of the peak spring bloom in 2019, estimated from satellite data, was earlier (6 May) than the long term average (15 May; 2003-2019) and earlier than 2018 (p. 67).
• Over the southern shelf, Rapid Zooplankton Assessments (RZA) in spring and fall indicated relatively high abundances of small copepods, low abundances of large copepods, and very low abundances of euphausiids. Similarly in the north, the fall RZA indicated small copepods were very abundant while both large copepod and euphausiid catches were low to zero (p. 80).
• The relative CPUE for jellyfishes in 2019 increased by 118% from 2018, the highest concentration observed since 2012 (p. 85).
• The 2019 Bristol Bay salmon inshore run of 56.6 million sockeye is the 4th largest on record since 1963 (p. 99).
• Abundance estimates for juvenile Chinook salmon were below average in 2019; low juvenile abundance increases the probability that bycatch caps will be reduced in the pollock fishery (p. 103).
• Juvenile pink salmon abundance has varied over time, but is generally higher in warmer years (2003- 2005; 2015-2019), and has increased with recent warming conditions (p. 106).
• The energy content of age-0 pollock diets was intermediate to low in 2018 (p. 87).
• Groundfish condition, based on length-weight residuals, was positive for all species measured in the southeastern bottom trawl grid in 2019; in the northern extension, Pacific cod and age-1 pollock residuals were positive while adult pollock residuals were negative (p. 108).
• The CEATTLE model estimates of age-1 predation mortality for pollock, Pacific cod, and Arrowtooth flounder continue to decline from the 2016 peak mortality. Pollock is at the long-term mean, while age-1 Pacific cod and Arrowtooth flounder mortality rates remain below the long-term mean (p. 113).
• Commercial crab biomass remained low in 2019 for Pribilof Islands blue king crab, St. Matthew Island blue king crab (although it increased from 2018), Tanner crabs, snow crab (males), and Bristol Bay red king crab. While female snow crab biomass remains above its long term mean, the biomass decreased from 2018 (p. 130).
• In the southeastern Bering Sea (Pribilof Islands) seabirds had relatively good reproductive success compared to recent years, yet a spatially and temporally comprehensive mortality event occurred for short-tailed shearwaters (p. 132).
• In the northern Bering Sea, the breadth of species impacted and temporal duration of seabird mortality events were noteworthy (p. 132). It is important to note that residents of the Bering Strait region remain concerned about seabird mortality events with respect to food security, public health, and conservation issues.
• The mean lifespan of the southeastern Bering Sea demersal fish community in 2019 is 30.2 years, and is the second highest in the time series. This is up from 27.6 years in 2018 and above the long-term mean of 28.2 years (p. 142).
• The mean length of the southeastern Bering Sea demersal fish community in 2019 is 37.2 cm, which is only slightly less than last year's peak value of 37.6cm (p. 143).
• The stability of groundfish biomass within the southeastern Bering Sea demersal fish community increased dramatically in 2019 to the highest of the time series (p. 145).
Fishing and Human Dimensions Trends
• The proportion of Chinook salmon bycatch in the Bering Sea has increasingly originated in British Columbia and the U.S. West Coast from 2011 through 2017 with significant declines in Chinook originating from Coastal Western Alaska. The stock proportions of chum salmon bycatch are variable with Northeast Asia and the Eastern GOA/Pacific Northwest stocks accounting for the majority of bycatch across years (p. 148).
• To date in 2019, groundfish discard biomass across the eastern Bering Sea for trawl sectors appears consistent with 2014-2018. Discard biomass in the fixed gear sector is lower in the southern Bering Sea and higher in the northern Bering Sea relative to 2014-2018 (p. 151).
• The number of seabirds caught incidentally in eastern Bering Sea in 2018 decreased 24% from 2017. Northern fulmars, shearwaters, and gulls were most commonly caught. The number of northern fulmars and shearwaters decreased compared to 2017 while gulls increased. An unusually high number of Laysan albatross were caught in 2018, but no short-tailed or black-footed albatross were caught (p. 156).
• As of June 30, 2019, no BSAI groundfish stock or stock complex is subjected to overfishing, is considered to be overfished, or to be approaching an overfished condition. Saint Matthews Island blue king crab status changed to overfished while snow crab biomass increased to above the B/BMSY threshold (p. 167).
• Landings in the eastern Bering Sea remained stable through 2018. Landings are predominantly from the pelagic forager group dominated by pollock. Trends in the apex predator group are driven by TAC levels in Pacific cod which saw a marginal drop in 2018 (p. 172).
• In 2018 prices for pollock increased. First-wholesale value dipped in the apex predator group as Pacific cod landings decreased and the average price of sablefish declined (p. 174).
• The unemployment rate in eastern Bering Sea communities decreased slightly to 2.9% in 2018. Unemployment rates in this region have been consistently lower than State and national rates and are the second lowest rate within Alaska regions. The unemployment rate in northern Bering Sea communities decreased to 11.8% in 2018, but have been consistently higher than State and national rates (p. 179).
• Between 2010-2018, the population in the southeastern Bering Sea increased 2.7%, which was higher than State trends (0.4%), yet 46% of communities within the region experienced population decline. The population in the northern Bering Sea increased 6.4% with 19.7% of communities experiencing population decline (p. 184).
• In the southeastern Bering Sea, school enrollment for schools under 25 students continues to trend downward consistent with overall decreasing school enrollment in most boroughs. The graduation rate has increased since 2015 from 75.6% to 78.5% in 2018. In the northern Bering Sea, school enrollment is relatively stable with no additional school closures in the last year. Graduation rates are highly variable across districts, but most are well below state graduation averages (p. 194).