Meeting Abstract

76.6  Sunday, Jan. 6  Ontogenetic shifts in oxygen uptake of Common Mudskipper (Periophthalmus kalolo) and its role in microhabitat selection SANDBERG, JS; DABRUZZI , TF; BENNETT, WA*; University of West Florida; University of West Florida; University of West Florida wbennett@uwf.edu

The Common Mudskipper, Periophthalmus kalolo, is a tropical, amphibious fish capable of utilizing both air and water as a respiratory medium. Although little is known about their early life history, smaller juveniles are thought to be more dependent on tidepools than adults. We quantified oxygen uptake in water and air of fish between 1.0 and 10.3 cm standard length to identify ontogenetic shifts in aquatic and aerial oxygen extraction ability. Mudskippers smaller than 4.0 cm in standard length exhibited aquatic mass-independent metabolic rates nearly twice those measured for larger fish (approximately 0.46 and 0.26 mg g^-0.8 h^-1, respectively). Aerial mass-independent oxygen uptake in juvenile mudskipper < 2.0 cm in length was ten times greater than values estimated for larger fish (3.80 and approximately 0.34 mg g^-0.8 h^-1, respectively). Furthermore, water:air metabolic rate ratios showed that emerged mudskippers < 2.0 cm in length consumed seven and one-half times more oxygen than when submerged. Our results suggest that tidepool dependence of small common mudskippers is not related to oxygen extraction limitations in air, but is more likely linked to attributes such as marked increases in metabolic rate, predation, desiccation or the need to enter pools to excrete ammonia.