US-GLOBEC NEP Phase IIIa-CCS: Synthesis of Euphausiid Population Dynamics, Production, Retention and Loss under Variable Climatic Conditions
W. Peterson [NOAA Northwest Fisheries Science Center], H. Batchelder [Oregon State University]

Project Summary

We sampled euphausiids on biweekly cruises at several hydrographic stations off Newport Oregon (1996-present), and over large scale spatial grids (1998-2003), resulting in a unique data set on temporal and spatial variations in the distribution and abundance of the euphausiids, Euphausia pacifica and Thysanoessa spinifera, in the northern California Current (NCC). We incubated adult and juvenile euphausiids during many of these cruises (since 1999) for measurement of egg production and molting rates, and we conducted experimental work in the laboratory on stage-specific development times, developmental pathways, age of first reproduction, brood size, inter-brood periods, and long-term variations of fecundity (> 9 months of daily observations). We propose to integrate and synthesize these data sets and other historical data on the distribution and abundance of euphausiid species in the California Current (e.g., Smiles and Pearcy 1971; Brinton 1976; Tanasichuk 1998a, b), and vital rates (e.g., Ross 1980) to (i) describe interannual variations in the distribution, abundance and vital rates of euphausiids in relation to climate variability, (ii) model their population dynamics (birth and death rates), growth rates, and secondary production, (iii) investigate mechanisms of transport, retention and loss in the Oregon upwelling system using coupled bio-physical and individual-base models, and (iv) produce a comparison of life history and population dynamics of the two species. Results will be synthesized (v) in the context of how climate variability may impact euphausiid populations in the NCC. Lastly (vi) data on interannual variations in euphausiid biomass and production will be used to test possible correlations with salmon growth and survival, leading to the development and testing of indices and mechanisms that may explain the extreme variations in salmon survival observed over the past decade.

Intellectual Merit - This long-term study compares the life history, population dynamics, vital rates, and production of co-occurring euphausiid species, Euphausia pacifica and Thysanoessa spinifera in the NCC, and includes synthesis of this large data set using a coupled bio-physical model of population dynamics. It contributes to the GLOBEC goal of defining mechanisms which link climate variability, population dynamics and production of euphausiids, and the growth and survival of salmonids in the northern California Current. We had the good fortune of observing the response of euphausiids and salmon to several types of climate variability, such as summers with strong vs. weak upwelling strong (1997/98) and weak (2003) El Niņo events, and a possible climate regime shift initiated in 1999. These events will allow us to test the response of GLOBEC target taxa, euphausiids and salmon, to these types of climate variability.

Broader Impacts - In terms of fisheries management, one of us (Peterson) has used GLOBEC NEP data to demonstrate that annual anomalies of copepod biomass are correlated with coho salmon survival, whiting growth (Peterson and Schwing 2003), and rockfish and sablefish recruitment-suggesting linkages between plankton productivity and fish recruitment in the NEP. The synthesis we propose is to extend these earlier results to mechanistically understand euphausiid dynamics in the context of variable ocean conditions, and to develop euphausiid-based indicators (predictors) of salmon survival. Similar plankton information is finding its way into the Fisheries Management decision-making process. During this synthesis research, we will be training a graduate student in numerical modeling of physical-biological processes, and continuing to involve undergraduate students as summer interns, including REU students.

NSF Award Summary

None available.

This page was last updated on March 14, 2007.

Maintained by:
Hal Batchelder
College of Oceanic and Atmospheric Sciences
Oregon State University
Corvallis, OR 97331-5503
phone: 541-737-4500; FAX 541-737-2064