Dataset: Larval fish abundance from Bongo plankton net tows
Deployment: BBB2104

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.