The North Coast Program is designed to measure and assess physical, chemical, and biological oceanographic properties as well as ecosystem and food web conditions known to affect salmonid survival at sea. To cover the extensive marine habitats of northern California salmonids, bi-monthly small vessel sampling of plankton on four transects, from Bodega Bay in the south to Newport, Oregon in the north, will be used to quantify food web variability and change. Sampling will include:
- station-based net (ring and Bongo nets, 0.20-0.25 mm and 0.30-0.35 mm, respectively) sampling and analysis of crustacean (i.e., copepod, euphausiid, decapods, and amphipod) and larval fish biodiversity (number of taxa), biomass, and stage/size
- hydrographic measurements that are known to affect zooplankton and larval fish distribution and abundance, hence salmonid survival
- prey ”patchiness”, particularly that of euphausiid crustaceans (”krill”) using scientific echosounders
- surveys of salmonid predators (seabirds, pinnipeds, and cetaceans)
Surveys of prey patches of euphausiid crustaceans and forage fish will be coordinated (at great cost savings) with ongoing surveys in the region, particularly the NOAA-NMFS-SWFSC Juvenile Rockfish Ecosystem Survey and California Current Ecosystem/Pacific Coast Ocean Observing System (PaCOOS) surveys (NOAA-NMFS-NWFSC). These surveys are planned in perpetuity and provide platforms for obtaining information that would be difficult and prohibitively expensive to obtain directly as part of the line-based sampling.
To measure ocean climate and place ecosystem (food web) observations and considerations in an oceanographic context, a variety of sampling techniques will be used including remote sensing (from satellites and the State’s HF radar coastal currents mapping system), mooring data, and new technology.
A cost-effective and scientific enhancement to hydrographic sampling on the survey lines will be the use of Spray Gliders. This new technology will allow for measurements of the water column (temperature, salinity, and a proxy for primary productivity) in all weather conditions and to sample salmon habitat between survey lines. This will facilitate rigorous computations to be made of environment changes (e.g., ocean warming, upwelling, stratification, mixed layer depth) that are known to affect the ecosystem and salmonid food webs.