Specimen Collection
Larval rockfish were collected using a 71cm diameter dual Bongo plankton net system with 505 µm mesh nets and equipped with a small CTD to record depth and physical variables during horizontal net tows at a ship speed of 1.5-2.5 knots down to 28.9-36 m depth.
Collection Location Details
This study is carried out within the temperate to subtropical Southern California Bight and surrounding coastal areas between 32° and 35° N, and 117° and 120° W. 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.
Specimen Processing and Measurement Methods
Once the net was retrieved the nets were gently rinsed with saltwater. The content of the cod-ends were immersed in a saltwater ice slurry to hopefully increase retention of gut contents, then concentrated onto a 300 µm mesh sized sieve, transferred into glass jars and preserved in tris-buffered 95% ethanol.
Rockfish larvae were sorted from the samples.161 individuals were selected to represent a range of sample stations and growth stages and measured (standard length, body depth, head length). Rockfish larvae were genetically identified as described in Thompson et al. (2016). The entire digestive tracts of the selected larvae were removed and dissected. Recovered prey items were identified to class or order level and by development stage (when applicable), length and widths were measured of all prey using an eyepiece micrometer, and measurements were converted to mm. Total body length was used for all organisms except copepods, where prosome length was measured instead. Length and width measurements are only given for prey intact enough to allow these measurements to be taken accurately.
Deployment Details
Each cruise is composed of one or more day trips using one of the two research vessels. The two-three letters indicate the research vessel, the four digits indicates YYMM.
- Winter 2021 sampling took place during cruises BBB2101 and BBB2102
- Spring 2021 sampling took place during cruses BBB2104 and SW2104