RELATION OF MEAN GROWTH-RATE TO CONCENTRATION OF PREY-SIZED PARTICLESFOR LARVAE OF PACIFIC HAKE (MERLUCCIUS-PRODUCTUS)

During February 1996, a combined OPC/MOCNESS was used to sample Pacifi c hake larvae (Merluccius productus) at twelve stations within or just offshore of the Southern California Eight. The OPC/MOCNESS simultaneo usly measured the horizontal and vertical distribution of hake larvae, the fine-scale distribution of prey-sized particles, and the temperat ure and salinity of the water column. In order to examine the relation between growth and particle concentration, I measured the size-at-age for 60 larvae from 6 stratified samples collected at five different s tations. Within the strata examined, the average particle concentratio ns ranged from 6.36 to 1.44 prey-sized particles L-1, and the average temperatures ranged from 10.5 degrees C to 12.4 degrees C. Estimates o f the average growth rate of larval hake contained within these sample s ranged from 0.135 to 0.279 mm d(-1). Within the range of temperature s examined, the average growth rate of larval hake collected in a samp le was not related to the average temperature of that sample (r(2) = 2 e(-6), p = 0.998). In contrast, there was a significant, positive rela tion between the average growth rate of larval hake within a stratum a nd the average concentration of prey-sized particles in that stratum ( r(2) = 0.795, p < 0.02).