Age-structured genetic analysis reveals temporal and geographic variation within and between two cryptic rockfish species

Abstract

The spatial patterns of genetic structure among juveniles of long-lived species can reveal the extent of interannual and geographic variation in realized larval dispersal as well as the processes that determine ecologically relevant patterns of population connectivity. However, few studies examine this temporal and spatial variation over large portions of a species' geographic range or between cryptic species that overlap in their range. Despite the potential for long-distance dispersal in blue rockfish Sebastes mystinus, a previous study of adults revealed two geographically distinct, cryptic species. To determine year-to-year variation in the patterns of spatial connectivity and to elucidate the potential ecological mechanisms involved in shaping new yearclasses and maintaining cryptic species, we sampled juveniles within California, USA, where both cryptic species coexist. Using microsatellite markers, we found geographic and temporal variation in the number of individuals from these distinct cryptic species within 2 new year-classes of juvenile S. mystinus. We also found differences in the geographic patterns of genetic structure of the 2 cryptic species. Whereas one species exhibited little or no spatial genetic structure across the study region, the other exhibited a complex geographic pattern of genetic structure, with little or no genetic structure among regions, but small-scale structure within a region. The results of this study demonstrate that the spatial scales and patterns of realized dispersal of pelagic larvae vary geographically, interannually, and between closely related species with similar life-history strategies. Therefore, estimates of dispersal based on larval duration and patterns of adult structure need to be interpreted cautiously.

Replicate divergence between and within sounds in a marine fish: the copper rockfish (Sebastes caurinus)

“…; Burford et al . ). Such biodiversity needs to be considered in conservation plans for marine fishes and their habitats (i.e.…”

Genetic Drift and Collective Dispersal Can Result in Chaotic Genetic Patchiness

“…Additional empirical studies on the larval phase before settlement will help determine if other species show similar patterns. A number of studies compare the genetic structure of recruited juveniles (i.e., postdispersal) with adults (Flowers et al ; Liu and Ely ; Muths et al ; Christie et al ; Burford et al ). It is important to note that under the conditions of our model, recruited juveniles and adults are predicted to have identical genetic structure (e.g., global F ST , pairwise F ST and F SS , local gene diversity H S ).…”

Sex matters: Otolith shape and genomic variation in deacon rockfish (Sebastes diaconus)

“…The deacon rockfish Sebastes diaconus Frable, Wagman, Frierson, Aguilar, and Sidlauskas () was recently distinguished as a separate species from the blue rockfish Sebastes mystinus (Jordan & Gilbert, 1881). Although superficially similar, these species represent distinct genetic lineages and exhibit key phenotypic differences such as body coloration and cranial morphology (Burford, ; Burford & Bernardi, ; Burford, Carr, & Bernardi, ; Cope, ; Frable et al, ; Hannah, Wagman, & Kautzi, ). These species occur in sympatry from northern California to central Oregon; however, the deacon rockfish has a more northern distribution—extending to Vancouver Island, British Columbia, whereas the blue rockfish is more southern—reaching northern Baja California (Frable et al, ).…”

“…The deacon rockfish Sebastes diaconus Frable, Wagman, Frierson, Aguilar, and Sidlauskas (2015) was recently distinguished as a separate species from the blue rockfish Sebastes mystinus (Jordan & Gilbert, 1881). Although superficially similar, these species represent distinct genetic lineages and exhibit key phenotypic differences such as body coloration and cranial morphology (Burford, 2009;Burford & Bernardi, 2008;Burford, Carr, & Bernardi, 2011;Cope, 2004;Frable et al, 2015;Hannah, Wagman, & Kautzi, 2015).…”