33.2 Thursday, Jan. 5 How sculpin pectoral fin morphology changes with demand across habitat transitions KANE, Emily A.*; HIGHAM, Timothy E.; University of California, Riverside; University of California, Riverside firstname.lastname@example.org
Aquatic organisms that occupy high-flow habitats often display traits associated with decreased drag and increased friction with the substrate. Sculpins (Scorpaeniformes: Cottoidea) have transitioned from deep-water marine habitats with low flow to shallow habitats with high flow, and likely exhibit changes in morphology for maintaining position in high flow habitats. We examined body and pectoral fin morphology of 9 species collected from deep, shallow, intertidal, and freshwater habitats; additionally, shallow subtidal and tidepool populations of Oligocottus maculosus were compared. Intact specimens and pectoral fins were measured, and multivariate techniques determined the morphological differences among habitat types. Principal components analysis (PCA) identified 4 functional groups, which were supported by a discriminant function analysis (DFA): pelagic Blepsias cirrhosus , deep forms, intermediate forms, and shallow forms. The transition from deep to shallow water is represented by two gradients: primarily, shallower forms had increased tail area and peduncle depth (specialization for acceleration) and larger pectoral fins with thicker, less webbed ventral rays (specialization for mechanical gripping); secondarily, shallower forms had more symmetrical fins with a greater aspect ratio and a reduced number of fin rays (specialization for negative lift generation). The function of sculpin pectoral fins likely shifts from primarily gripping in deep (low flow) habitats to an equal dependence on gripping and negative lift generation in shallow (high flow) habitats. Together, these morphological characteristics likely minimize drag and increase friction with the substrate to increase station-holding capability for species in high-flow habitats.