Age and growth of the Giant Kelpfish, Heterostichus rostratus Girard 1854, in Southern California, USA

Summary In order to update existing life history parameters, age and growth patterns were determined for Giant Kelpfish, Heterostichus rostratus sampled from nearshore kelp forest and estuary habitats in southern California (USA) from April 2012 through June 2015. Fish were collected by pole spear, beach seine, beam trawl, purse seine, and square enclosure. Using age-at-length data derived from otolith readings, Giant Kelpfish were found to have a relatively short life span with the largest examined fish reaching a maximum total length of 413 mm at an age of 5 years. Von Bertalanffy growth parameters estimated for this species were: L∞ = 45.1 cm, k = 0.25, t0 = −0.66. Standard length (SL, cm)-total length (TL, cm) and total length (TL, cm)-weight (W, g) relationships were described by the equations: SL = 0.90 TL – 1 and W = 2.21 × 10−3 TL3.39, respectively. Wild juvenile Giant Kelpfish collected for this study had a higher growth rate than laboratory-reared fish from a previous study.