Distribution and Recruitment of Young-of-the-Year Giant Sea Bass, Stereolepis gigas, off Southern California
This study identified nursery habitat, recruitment patterns, the planktonic larval duration (PLD), size and age at settlement, and growth rate of the young-of-the-year (YOY) Giant Sea Bass (GSB), Stereolepis gigas, off Southern California. A total of 160 YOY GSB were sighted on 150 transects over a three-year period. Young-of-the-year GSB were relatively rare (maximum density of 40/ha) and recruitment was limited to a few areas. In 2014–2015, densities of YOY GSB were significantly higher at six locations off sandy beaches nearest the heads of submarine canyons off Redondo Beach, Newport Beach, and La Jolla, California. The vast majority of occurrences of YOY (73%) were within 500 m of the heads of submarine canyons. Three color phases of YOY were discovered ranging (smallest to largest individuals) from black to brown to orange. Recruitment occurred from July through February with peak abundances occurring in the late summer months from August through October. YOY occurred at depths from 2 m to nearly 10 m. Overall, size of YOY GSB increased with depth in the shallow sand riffle zone. YOY grew rapidly at 1.23 mm/day (n = 23) with collected individuals ranging from 31 to 84 d old based on daily ring increments in otoliths. The planktonic larval duration was estimated to be about one lunar month (26.8±2.4 d) based on the presence of the first settlement check and size of earliest settlers. Size at settlement was estimated to be 14.4±3.0 mm TL (10.6±2.5 mm standard length [SL]). This information adds substantially to our knowledge of early developmental processes and recruitment patterns of Giant Sea Bass that are crucial to our understanding of their life history and to making informed decisions regarding fisheries management policies and conservation efforts.
A YOY Giant Sea Bass photographed over a typical, nearshore, sandy bottom off the Southern California coast. Inset top: an adult Giant Sea Bass, Stereolepis gigas, estimated at 2 m in total length photographed off Catalina Island, California. Photo credit: Mike Couffer.
(A) Photograph of a young-of-the-year Giant Sea Bass in the black phase that ranged from 10–21 mm in total length. (B) Brown phase that ranged in size from 23–33 mm TL. (C) Orange phase that ranged in size from 41–186 mm TL. Photo credit: Mike Couffer.
The size (mm TL) and color phase of young-of-the-year Stereolepis gigas observed by date in surveys conducted in 2014 (top) and 2015 (bottom).
The mean density (number of individuals/m2 ±1 SD) found in transects by location of the GSB from north to south in the Southern California Bight from 2013 to 2015. Densities at the non-zero locations were indistinguishable from one another statistically.
Distribution map of young-of-the-year GSB observed off Southern California. The bars represent the densities of individuals seen (# per ha). Ovals represents sites surveyed which had zero sightings. The line represents the depth contour line where submarine canyons meet shallow sandy beach areas.
Numbers of individual YOY GSB observed and their estimated distance (m) from the head of a submarine canyon off the coast of Southern California.
Total length (mm) of the YOY GSB individuals observed by depth (m) of occurrence from 2013–2016.
Observed age in days at total length (mm) for Stereolepis gigas (n = 23) taken from Southern California based on daily ring counts.
Contributor Notes
Associate Editor: K. Martin.