National Oceanic and
Atmospheric Administration
United States Department of Commerce


FY 2009

Larval fish abundance and physical forcing in the Gulf of Alaska, 1981-2003

Doyle, M.J., S.J. Picquelle, K.L. Mier, M.C. Spillane, and N.A. Bond

Prog. Oceanogr., 80(3–4), 163–187, doi: 10.1016/j.pocean.2009.03.002 (2009)

The present study investigates ecological patterns and relationships to environmental variables among a time-series of larval fish species abundance from late spring surveys (1981-2003) in the northwest Gulf of Alaska (GOA). Links between interannual variation in species abundance and the physical environment were explored using generalized additive modeling (GAM). Trends in larval abundance and connections with physical variables displayed patterns that indicate unique and complex responses among species to environmental forcing during the larval period. In particular, the observed patterns suggest that ontogenetic-specific responses, representing sub-intervals of early life, are important. In addition, a notable degree of synchrony in larval abundance trends, and similarity in links with physical variables, were observed among species with common early life history patterns. The deepwater spawners, northern lampfish, arrowtooth flounder, and Pacific halibut, were most abundant in the study area during the 1990s, in association with enhanced wind-driven onshore and alongshore transport. Years of high abundance for Pacific cod, walleye pollock, and northern rock sole were associated with cooler winters and enhanced alongshore winds during spring. High larval abundance for spring-summer spawning rockfish species and southern rock sole seemed to be favored by warmer spring temperatures later in the time-series. This apparent exposure-response coupling seems to be connected to both local-scale and basin-scale environmental signals, to varying degrees depending on specific early life history characteristics. Understanding such ecological connections contributes to the evaluation of vulnerability and resilience among GOA species' early life history patterns to fluctuating climate and oceanographic conditions. This investigation also provides crucial information for the identification of "environmental indicators" that may have a broad-spectrum effect on multiple species early life history stages, as well as those that may be more species-specific in exerting control on early life history survival. Of particular interest was the emergence of the EP-NP (East Pacific-North Pacific) teleconnection index as the top-ranked variable in the CAM models exploring the connections between late spring larval abundance and the physical environment. The EP-NP index represents an important and often primary mode of spring-summer atmospheric variability in the northeast Pacific, with a strong expression in the GOA, and its connection with species in this study implies that it may be a climate mode of significant ecological importance.

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