Dataset: Abundances of larval Northern Anchovy (Engraulis mordax), Rockfish (Sebastes spp., and other/unidentified larvae from Bongo plankton net tows conducted in the subtropical Southern California Bight from January to April 2021

This study was carried out within the temperate to subtropical Southern California Bight and surrounding coastal areas between 32° and 35° North, and 117° and 120° West. Specific locations sampled fall within the CalCOFI and CCE-LTER programs' quarterly survey grid from lines 76.7 to 93.4 and stations 26 to 55.

Sampling took place from January to April 2021 on R/V Bob and Betty Beyster cruises BBB2101, BBB2102, and BBB2104 and on R/V Shearwater cruise SW2104. Each cruise number is composed of one or more day trips using one of the two research vessels. The two-three letters indicate the research vessel, and the four digits indicate YYMM.

Larval fish were collected using a 71-centimeter (cm diameter dual Bongo plankton net system equipped with a small CTD to record depth and physical variables during horizontal net tows at a ship speed of 1.5 to 2.5 knots down to 14 to 36 meters (m) depth, depending on bottom depth. The Bongo was equipped with two 505-micrometer (µm) mesh-size nets and a flowmeter mounted in the center of one of them.

Once the net was retrieved the cod-ends were immediately placed in a saltwater ice bath and the nets were gently rinsed with saltwater. The content of the cod-ends was then concentrated onto a 200-300 µm mesh-size sieve, transferred into glass jars, and preserved in Tris-buffered 95% ethanol as quickly as possible. After a few days of storage, the alcohol was exchanged. The samples were sorted under a dissecting microscope and fish larvae were identified based on body shape and pigmentation patterns.

Known Problems/Issues:
The Rockfish data contain some gaps for samples where they were not identified and counted. In those cases, any Rockfish present will be included in the Other / Unidentified category.