Identification of marine fish eggs in Taiwan using light microscopy, scanning electric microscopy and mtDNA sequencing

Abstract

A previously published study used light microscopy, SEM and mtDNA sequencing to identify eggs of 104 taxa to species, 24 to genus and 67 to family levels; 28 of the species were identified by hatching methods and 23 species of eggs were obtained from aquaculture farms (in which the species were known). Light-microscopic characters of 10 species that have not previously been reported are described in the present paper. It is concluded that (1) more diagnostic characters can be found by SEM than by light microscopy, (2) different species may share identical egg morphology even under SEM, so identification using morphological characters is better applied to the categories of family or genus only, not to species, and (3) in addition to the hatching method, molecular sequencing is an alternative way to assign an egg to a species as well as to verify the correctness of previous morphological identification. This necessitates use of the same egg for both morphological observations and DNA sequencing. Its feasibility and experimental process are demonstrated in the present paper using lizardfish (Synodontidae) as an example.