Developing a Rapid, Accurate, DNA-based Identification Technique for Larvae
and Dietary Components of Commercially Important Marine Fish Species
Figure 4. (A, left) Digested forage fish obtained from gut. (B, right) Unidentified Bathymaster spp. larva. Photos by Mei-Sun Yang (left) and Morgan Busby (right).
Correctly identifying 'who eats whom' in the ocean is critical to constructing food webs and understanding how marine ecosystems function. Identification of prey remains in predator stomachs is often inconclusive; for example, prey may be in an advanced state of digestion (Fig. 4A).
Figure 5. Restriction fragment length polymorphism (RFLP) patterns for three species of forage fish. Lanes 2-5 contain individual capelin, lanes 6-9 contain eulachon and lanes 10, 12 and 13 contain Pacific sand lance. Lanes 1 and 15 contain DNA size standards of known fragment lengths. Photo by Melanie Paquin.
Members of the Recruitment Processes Program, in collaboration with the Resource Ecology and Fisheries Management (REFM) Division, recently completed a North Pacific Research Board-funded project focused on developing rapid, accurate, DNA-based identification of larvae (Fig. 4B) and dietary components of commercially important species.
Mitochondrial DNA restriction fragment length polymorphism (RFLP) protocols were developed for 19 fish species that produced diagnostic banding patterns with gel electrophoresis (Fig. 5).
The results indicated that DNA-based methods can provide accurate species identification or verification in food habits studies or for larval fish when traditional morphometric and meristic approaches are uninformative or taxonomic expertise is lacking.
By Mike Canino, Troy Buckley, Melanie Paquin, and Richard Hibpshman
