Estimates of Age, Growth, and Settlement from Otoliths of Young-of-the-Year Kelp Bass (Paralabrax clathratus)

Abstract

Settled young-of-the-year (YOY) and older juvenile kelp bass {Par- <br /><br />alabrax clathratus) were collected off the coast of southern California during the <br /><br />summers of 1989 and 1990. Daily rings on the sagittae of settled YOY kelp bass <br /><br />were used to determine age, estimate growth, and construct ring width profiles <br /><br />for each fish. Laboratory-reared larvae revealed that ring deposition began on the <br /><br />third day after hatching, and confirmed the daily periodicity of ring deposition. <br /><br />The combined 1989-90 growth curve could be described as a linear regression <br /><br />with the equation (length (mm)) = 14.67 + 1 .69(age(days)) (r = .96), resulting <br /><br />in an average daily growth of 0.59 mm/day for the first 90 days of life. Back- <br /><br />calculated spawn dates suggested a possible lunar periodicity around the full <br /><br />moon. Settlement checks and otolith ring widths were used to determine the time <br /><br />of settlement and explore the possibility of delayed settlement in this species. The <br /><br />average age-at-settlement was calculated to be 30 days, with a range of 25-36 <br /><br />days. Only a single case of delayed settlement was evident from the increment- <br /><br />width profiles of 22 fish.