Evidence is accumulating that climate change may be already influencing the fish distribution of some fish stocks worldwide. Local differences in the spatial extent of range shifts of several species can be explained by climate velocity. These findings suggest that it might be possible to project future spatial distributions of fish and fisheries from extrapolations based on the rates of spatial shifts in temperature. While at a gross spatial scale, evidence shows “climate velocity” matters, knowledge of behavioral responses by marine organisms to environmental variability suggests that other factors may impede or buffer the direct response of species to shifts in oceanographic conditions. Important lessons can be learned from analysis of extreme events in nature.
We seek an Associate who will assist in the examination of a unique suite of events that provide an unprecedented opportunity for monitoring groundfish responses to warming ocean conditions. In the fall of 2013 an unusual warming phenomena appeared in the North Pacific. This warming event was extraordinary with sea surface temperature departures being significantly warmer than the long-term mean. This warm event persisted through 2014 and intensified in 2015 in response to emerging El Niño conditions. Fortuitously, the National Marine Fisheries Service (NMFS) and the Department of Fisheries and Oceans conducted acoustic and bottom trawl surveys in the California Current System (CCS), the west coast of British Columbia, and the Gulf of Alaska (GOA) in 2015. This alignment of summer survey effort in a year of projected extreme warming conditions set up an extremely rare opportunity to study living marine resource responses to a warming condition by augmenting fish surveys with the equipment necessary to collect the data needed to substantially improve our understanding of groundfish spatial responses to anomalously warm ocean conditions. We seek a candidate with knowledge and experience using spatial statistics, and fisheries ecology. The candidate will evaluate the following hypotheses:
(1) Selected groundfish will shift their ranges in response to shifts in the distribution their respective historical climatic envelope of ocean conditions. (a) Selected groundfish will shift their ranges in response to changes in the distribution of suitable ocean conditions. (b) Selected groundfish will shift their ranges in response to changing currents rather than changing climate envelopes.
(2) Selected groundfish will shift their ranges in response to the expected rate and direction at which isotherms shift in response to the extreme warm conditions.
(3) Groundfish that can tolerate a broad bathymetric range will move to deeper waters rather than shifting their geographic range.
(4) Responses of shallow-water species (<50 m) and coastal pelagic species (CPS) will be stronger than deep-water species (>200 m). Alternatively, responses of shallow water species and CPS will be less evident because they are better adapted to variable ocean conditions during summer.
The successful candidate will be responsible for assessing within species differences in distribution across areas and between species differences in distribution across life history types. In the case of bottom trawl data, the candidate will correct the survey for net selectivity based and catchability based on available estimates from stock assessments and past surveys. The focal species for this study will be (gadids [Pacific hake, walleye Pollock], sablefish, rockfish [Pacific Ocean perch, widow rockfish], and flatfish [rock sole, arrowtooth flounder, English sole, and petrale sole]). The successful candidate will develop spatio-temporal models that will incorporate habitat variables—including the observed ocean conditions—to establish functional relationships between fish distribution and the environmental conditions. We expect that size groups will be treated separately for at least Pacific hake, walleye pollock, Pacific cod, and Pacific Ocean perch. For each species, distribution patterns will assessed at the leading and trailing edges of the distribution, as well as estimates of range surfaces. Once these distribution indicators have been developed the candidate will compare relationships observed in 2015 (an extreme warm year) with observations in cool, warm, and average ocean conditions.
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Pinsky ML, Fogarty M: Lagged social-ecological responses to climate and range shifts in fisheries. Climate change 115(3-4): 883-981, 2012
Whitney FA: Anomalous winter winds decrease 2014 transition zone productivity in the NE Pacific. Geophysical Research Letters 42: 428-431, Doi: 10.1002/2014GL062634, 2015
Climate change; Stock assessment; Ecosystem indicators; Groundfish; North Pacific; Modeling;