Life History Through the Eyes of a Hogfish: Evidence of Trophic Growth and Differential Juvenile Habitat Use

Understanding ontogenetic linkages among fish habitats is critical for conservation of fish populations and the ecosystems on which they rely. Natural tags such as stable isotopes are an effective tool commonly used to investigate ecological questions regarding fish movement and habitat use. Here, I analyzed stable isotopes from the sequentially deposited laminae of Hogfish (Lachnolaimus maximus) eye lenses from the eastern Gulf of Mexico (eGOM) to investigate trophic and geographic changes across individual life histories. I documented evidence of entire-life scale trophic growth through increases in δ15N. I also observed depth separation at the juvenile stage, evidenced by variation in δ13C. These results suggest that Hogfish inhabiting deeper adult habitats likely inhabited deeper juvenile habitats (i.e., nearshore reefs), while adult Hogfish inhabiting shallower adult habitats likely used shallower juvenile habitats (i.e., estuaries). This is a novel finding for eGOM Hogfish and contradicts prior literature that solely discuss seagrass as juvenile Hogfish habitat. A linear discriminant function analysis revealed the Cedar Key region to be the most highly used juvenile habitat by the Hogfish sampled in this study, but more evidence is needed to determine the status of this area as a Hogfish nursery. This study provides the first evidence for ontogenetic migration of individual Hogfish using natural tags as tracers and demonstrates a mechanism for identifying juvenile habitats based on eye lens stable isotope analysis. Identifying ontogenetic patterns and habitat use in Hogfish can help to better manage the stock and preserve essential habitats