The 2018 Summer California Current Ecosystem Survey, a joint survey conducted by the Southwest Fisheries Science Center's Fisheries Resources Division and Marine Mammal and Turtle Division, is scheduled for 26 June through 23 September aboard the NOAA Ship Reuben Lasker. Our scientists will survey the distributions and abundances of pelagic fish stocks, marine mammals, their prey, and their biotic and abiotic environments along the West Coast of North America from Vancouver Island, Canada to the U.S.-Mexico border.
This survey will also be coordinated with five autonomous Saildrones instrumented with echosounders and other oceanographic sensors to compare results from the two platforms and to explore the potential for using Saildrones to survey pelagic fishes in nearshore areas that are often inaccessible to the NOAA ships.
September 24, 2018
During 80 days at sea between June 26 and September 23, 2018, the Fisheries Resources Division collaborated with the Marine Mammal and Turtle Division to conduct a survey of the California Current Ecosystem, between Cape Scott on Vancouver Island, Canada, and San Diego, CA. Acoustic sampling and visual observations of marine mammals and seabirds were conducted along 106 daytime, east-west acoustic transects totaling 5,122 nmi. To estimate the proportions of coastal pelagic species and their lengths, catches were analyzed from 167 surface trawls combined into 64 trawl clusters. These data and acoustic-trawl method are used to estimate the distributions and abundances of the northern and central sub-populations of northern anchovy, the northern sub-population of Pacific sardine, jack and Pacific mackerel, herring, and euphausiid species.
Transect densities were adaptively doubled in the areas with high coastal pelagic species backscatter, i.e., between Cape Flattery and Cape Mendocino, and between San Francisco and Morro Bay. Krill densities were highest between Cape Flattery and Cape Mendocino. Samples from the Continuous Underway Fish Egg Sampler indicated that anchovy were spawning off Oregon and Washington, and between San Francisco and San Diego; and jack mackerel were spawning throughout the survey area, but farther offshore.
Trawl catches show that the forage fish assemblage was dominated by herring off Vancouver Island, anchovy from central Washington to central Oregon, jack mackerel from central Oregon to Bodega Bay, and anchovy from San Francisco to Point Conception. Off Southern California, there were patches of jack mackerel offshore, sardine around the Channel Islands, and anchovy nearshore. Although FSV Reuben Lasker typically does not survey shallower than ~ 50-m depth, CDR Chad Cary routinely extended the eastern ends of the Summer 2018 Survey transects into ~20-m depths. This notable effort provided observations for directly estimating coastal pelagic species closer to shore.
A Fisheries Resources Division/Marine Mammal and Turtle Division workshop will be held in November to progress analyses of environmental forcing and predator-prey interactions. In addition to this collaboration with the Marine Mammal and Turtle Division, the Fisheries Resources Division collaborated with researchers from the Northwest Fisheries Science Center and Saildrone, Inc. (www.saildrone.com) to assess the use of five instrumented autonomous sailboats for augmenting ship-based fisheries and ecosystem surveys.
The objectives were to:
- Evaluate the operational feasibility of using Saildrones to conduct large-area surveys of demersal and pelagic fishes.
- Survey nearshore where the ship cannot safely navigate, to reduce potential sampling bias.
- Survey prior to the ship, to better allocate ship time for improving biomass-estimate precision.
- Study a small area over multiple days, to study vertical migration and schooling behaviors.
- Survey migrating fish stocks, to improve the efficiency of collecting ecosystem data.