National Oceanic and Atmospheric Administration, Integrated Ocean Observing System
Using ocean data assimilation to incorporate environmental variability into sardine and squid assessments
Arthur J. Miller, Sam McClatchie (NOAA/NMFS/SWFSC), Kevin Hill (NOAA/NMFS/SWFSC)
William Hamner (UCLA), Lou Zeidberg (UCLA),
David Checkley (SIO), Bruce Cornuelle (SIO), John McGowan (SIO),
Tony Koslow (SIO)
and Tim Baumgartner (CICESE)
Award: ~$270,000
Duration: 2008-2011
Project Summary.
Sardine and market squid are important fisheries in the California Current System (CCS) from Mexico to Canada as a commercial fishery whose stocks are actively managed and as forage fish for other important commercial stocks such as tuna. The current sardine and squid stock assessment assumes that spatial variability is not a major influence. In fact, this assessment is unique by including the sea-surface temperature (SST) time series at Scripps Pier in La Jolla, CA, in the final management decision. Although the Scripps pier SST is broadly coherent with large-scale SST all along the coast on climatic timescales, there is also tremendous mesoscale and interannual spatiotemporal temperature variability throughout the CCS, as well as in other biologically relevant fields, such as upwelling, squirts, streamers and eddies.
Local temperature, along with forage and predation are known to affect the growth and condition of sardine and squid. Since both move yearly inshore and offshore along the entire coast of the U.S., the spatial components of temperature and forage on stock recruitment are likely to be important.
We therefore propose to investigate whether this spatial component can be quantified using IOOS (SCCOOS and CeNCOOS) datasets in the CCS, supplemented with other observations. Our overall goal is to develop a coupled ecological and hydrologic model for assessing and predicting the physical oceanographic influences on sardine and squid stocks using both the Regional Integrated Ocean Observing System datasets in the California Current System and NOAA.s Fisheries and CalCOFI data. The resulting forecast will be presented the sardine and squid stock managers and scientists for consideration in the catch quotas for these species.
The project will include extensive analysis of the various IOOS data using sophisticated ocean data assimilation tools. For example, detailed oceanic temperature fields will be combined with statistical analysis of the spatial and temporal observed distributions of sardine and squid eggs, larvae, recruits and populations, to develop a better understanding of environmental controls on these important marine populations.
We will develop spatial models to relate sardine larvae and squid paralarvae to objectively selected environmental variables from the assimilated ocean physical fields, including temperature, salinity, mixed layer depth, currents, eddies, fronts, and water column stability, plus other relevant biological variables such as chlorophyll and zooplankton biomass. The selected environmental variables will be supplemented with measures of sardine and squid condition, derived from length-weight regressions of larvae and of adults.
We aim to characterize the ocean (pelagic) habitat suitable for sardine production and use assimilated ocean fields to identify the physical processes that influence development of this habitat. The real puzzle that fisheries oceanographers have struggled with over the past several decades is why sardine grow in abundance during warm periods associated with anomalously low upwelling and low production along the coast. We are proposing that it is not raw plankton production that is important for sardine survival, but production of suitable prey, i.e. plankton within a certain size range, specifically smaller plankton sizes resulting from weaker upwelling driven by wind-stress curl. Plankton community structure is a habitat characteristic that can be accurately estimated by examination of physical environmental variables.
We will also compare the assimilated ocean fields to two aspects of squid biology, hatchling abundance and egg bed habitat, and to then compare to fishery landings data. Squid pre-recruit indices will be derived from paralarvae distribution and abundance.
We will also establish the relationships between variations in the abundance of larval fish species and the abundance of functional groups of predators and prey over time and space as diagnosed in the assimilated ocean physical fields and examine the physical/chemical oceanographic variables associated with the correlations that we expect to find.
This research bridges NOAA NMFS-SWFSC scientists with UCSD and UCLA researchers, and unites physical oceanographers with fisheries biologists to develop an integrated analysis of physical-biological interactions with applications in fisheries management. This work is expected to provide the following benefits:
* Enhance the value of environmental data incorporated into decision rules used in the sardine assessment.
* Assess the predictability of fisheries for management forecasts.
* Provide experimental forecasts one year in advance predicting favorable or unfavorable recruitment of sardine and squid.
* Provide a more mechanistic understanding of the environmental forcing that contributes to inter-annual fluctuations in the abundance of sardine and squid.
* Provide a better understanding of key forage species for sardine and squid.
* Motivate young students (undergraduate work-study trainees) to pursue careers in marine fisheries, provide educational research opportunities for a Ph.D. student, and furnish additional educational opportunities in multi-disciplinary ocean sciences for a recent Ph.D. post-doctoral researcher.
The primary user of this work will be the Coastal Pelagic Species Management Team (CPSMT) and Scientific and Statistical Committee (SSC) of the Pacific Marine Fisheries Management Council (PMFMC) who review scientific advice on sardine harvests for the entire West Coast.
IOOS PI Meeting November, 20, 2008