Rockfish Genus Sebastes Research Articles

Rockfish ( Sebastes) that are evolutionarily isolated are also large, morphologically distinctive and vulnerable to overfishing

In an age of triage, we must prioritize species for conservation effort. Species more isolated on the tree of life are candidates for increased attention. The rockfish genus Sebastes is speciose (>100 spp.), morphologically and ecologically diverse and many species are heavily fished. We used a complete Sebastes phylogeny to calculate a measure of evolutionary isolation for each species and compared this to their morphology and imperilment. We found that evolutionarily isolated species in the northeast Pacific are both larger-bodied and, independent of body size, morphologically more distinctive. We examined extinction risk within rockfish using a compound measure of each species’ intrinsic vulnerability to overfishing and categorizing species as commercially fished or not. Evolutionarily isolated species in the northeast Pacific are more likely to be fished, and, due to their larger sizes and to life history traits such as long lifespan and slow maturation rate, they are also intrinsically more vulnerable to overfishing. Finally, the set of northeast Pacific species that are both fished and most intrinsically vulnerable to fishing are among the most evolutionarily distinctive. These findings suggest that, at least for this clade, extra attention should be paid to evolutionary distinctiveness when prioritizing species for conservation.

210Pb/226Ra Determination of Longevity in Redfish

Examination of annular growth rings apparent in charred otolith cross sections is the basis for reports of extreme longevity in the rockfish genus Sebastes, but the interpretation of the annuli has long been disputed. We used a radiochemical assay of the otolith core to confirm our interpretation of annuli in Atlantic redfish, Sebastes mentella, to at least an age of 65 yr. Through measurement of the radioactive disequilibrium between 226Ra and 210Pb, it appears that redfish live to an age of at least 75 yr in the waters off of Nova Scotia.