Annual recruitment of three species of tide-pool fishes is driven by variation in springtime coastal hydrodynamics
Limnol. Oceanogr., 54(5), 2009, 1481-1487 | DOI: 10.4319/lo.2009.54.5.1481
ABSTRACT: Using an 18-yr time series of annual recruitment of three tide-pool fishes, Clinocottus globiceps, Clinocottus embryum, and Oligocottus maculosus, we investigated the relationship between recruitment and upwelling and downwelling, date of the spring transition, and spring wave climate. There were no significant regressions between springtime upwelling and recruitment in any species. The timing of the spring transition, however, was related to the recruitment of C. globiceps and C. embryum: the later the spring transition the larger their annual recruitment. We found a negative exponential relationship between timing of the spring transition and O. maculosus recruitment, though only after removing one outlying data point (the strong 1997 El Nino year). Significant negative exponential regressions were also found between O. maculosus recruitment and hours in April and May when waves were <2 and <3 m in amplitude. In these regressions, 1997 was no longer an outlier. O. maculosus recruitment also varied positively with seawater temperature on the shore. The different hydrodynamic correlates of recruitment in this assemblage of species, as well as published observations, suggest that the larvae of these species are occupying different nearshore areas. Clinocottus species likely develop in coastal waters, while O. maculosus develops very close to shore, essentially in the surf zone, where its larvae may be swept offshore by currents generated during large wave events. Abiotic factors driving larval success can explain persistent differences in recruitment among these species over 18 yr.