Do genetically distinct rougheye rockfish sibling species differ phenotypically?

Two cryptic species of rougheye rockfish Sebastes aleutianus, which we refer to as types I and II, have been identified independently from DNA (microsatellite and mitochondrial DNA [mtDNA]) markers and from distributions of allozyme allele frequencies. Visual differences that discriminate between these species in the field would improve their conservation and management. To delineate species, we used two microsatellite loci, mu Sma6 and mu Sma7, in conjunction with mtDNA site differences for the restriction enzymes Cfo I in the region of NADH dehydrogenase (ND) subunits 3 and 4 and Mbo I in the region of ND subunits 5 and 6. We compared meristic characters and morphological dimensions of the genetically determined species and observed that although all parameters had overlapping distributions, type II rougheye rockfish have slightly fewer and shorter gill rakers and deeper bodies. Discriminant analysis of morphological characteristics accurately delineated the species (> 94%). Rougheye rockfish have two color forms: light and dark. We examined the correlation between coloration and genotype and observed that most type II fish had the light coloration, but type I fish were either light or dark and the proportion of each color form changed geographically. We also demonstrated that frequency differences in the distributions of allozyme markers are concordant with diagnostic differences at microsatellite loci and mtDNA markers, although the allozyme markers are not diagnostic.