Wednesday, June 27, 2018

[Ichthyology • 2018] Distribution and Recruitment of Young-of-the-Year Giant Sea Bass, Stereolepis gigas, off Southern California


Young-of-the-Year  Giant Sea Bass, Stereolepis gigas Ayres, 1859

in Benseman & Allen. 2018. 

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.

Fig. 1. A YOY Giant Sea Bass, Stereolepis gigas, photographed over a typical, nearshore, sandy bottom off the Southern California coast.
Inset top: an adult Giant Sea Bass estimated at 2 m in total length photographed off Catalina Island, California.

 Photo: Mike Couffer.

Stephanie A. Benseman and Larry G. Allen. 2018. Distribution and Recruitment of Young-of-the-Year Giant Sea Bass, Stereolepis gigas, off Southern California. Copeia. 106(2); 312-320. DOI: 10.1643/CE-18-021 


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