Meeting Abstract

89-4  Saturday, Jan. 7 11:00 – 11:15  Osmoregulatory plasticity during hypersalinity acclimation in a euryhaline teleost MARTIN, LM*; ESBAUGH, AJ; The University of Texas at Austin; The University of Texas at Austin leighann.martin@utexas.edu

Prolonged drought and diversion of freshwater inflow into estuaries are making periods of hypersalinity more common in coastal systems. This is especially true in the Laguna Madre system along the Texas coast where salinities regularly exceed 70 ppt. As such, the ability to tolerate hypersalinity is critical to the success of species within these environments, such as the commercially important red drum (Sciaenops ocellatus). This study evaluated acclimation of red drum to hypersalinity (60 ppt) using a direct transfer protocol. Hypersalinity exposure resulted in significant impacts on plasma osmolality and muscle water within the first 24 h. These changes returned to control values coincident with a significant increase in intestinal water volume, which suggests increased osmoregulatory capacity as a result of acclimation. Acclimation to hypersalinity also resulted in significant upregulation of NKA and VHA enzyme activity for the posterior intestine and gills at 72 h post-transfer. Gene expression data supported these findings and additionally demonstrated a strong response for nkcc1 and nkcc2 in the gills and intestines, respectively. Overall, these data show that red drum are capable of tolerating acute bouts of hypersalinity exposure through osmoregulatory plasticity.