Species Identification And Phylogeny Of Phycinae Hakes And Related Gadoid Fishes

The term hake refers to a number of species belonging to multiple families of fish in the suborder Gadoidei and includes two main groups: Phycinae hakes (family Gadidae) and Merluccius spp. hakes (family Merlucciidae). The use of the common name hake for this diverse group of fish prompts questions such as: how are these species related and how can they be differentiated? Chapter one details the development of the Rapid Gadoid Identification Assay (RaGIA) for molecular identification of 11 gadoid fishes (including six hakes) using Polymerase Chain Reaction Restriction Fragment Length Polymorphism (PCR-RFLP). RaGIA was used for species identification of fillets of hake, pollock and haddock sold in southern Maine markets. Testing found that market labeling was accurate; however, there were inconsistences in the labels provided by the fish distributors (from whom the markets obtained their fillets). Chapter two explores the development of a phylogeny, based on a mitochondrial DNA gene and a nuclear encoded gene, which includes members of the families Gadidae and Merlucciidae. The resulting phylogeny was used for morphological character mapping and investigation of trait evolution in this group. Consistent with previous studies, the analysis resolved the families Gadidae, as well as several subfamilies, and Merlucciidae with strong support. The putative Lotinae subfamily clade was not resolved in this analysis and suggests that further study is needed to investigate the monophyly of this group. The three dorsal fins and two anal fins morphological states as well as the life history characteristic of the absence of an egg oil globule were all found to be characteristic of the Gadinae, the most derived clade of the Gadoidei