Recruitment variability in populations of long rough dab (American plaice) hippoglossoides platessoides (fabricius) in the North Atlantic

Abstract

Wide geographic variation in interannual recruitment estimates of age-4 long rough dab (American plaice) Hippoglossoides platessoides was evident in eleven populations in the western North Atlantic and three populations in the eastern North Atlantic. Where data existed for early juveniles, ages 0–2, recruitment variability declined with age, but the magnitude of reduction differed suggesting density-dependent geographic variation in regulation of year-class strength at the juvenile stage. On a large spatial scale, recruitment variability in long rough dab showed an increasing south to north latitudinal gradient rejecting the hypothesis that variability was higher at the edges of the range and least in the centre. Recruitment patterns were correlated over the geographic range of the species to examine timing in year-class synchrony. No large-scale patterns emerged, but some adjacent populations showed synchrony in year-class strength, suggesting that a commonality of processes regulating year-class strength existed, but only over short distances. In the western North Atlantic both significant positive and negative correlations in recruitment patterns were found, suggesting that recruitment in long rough dab was under the influence of physical (temperature) and biological interactions.