Condition As an Indicator of Resilience to Hypoxia By Atlantic Croaker in the Northern Gulf of Mexico

The extent of seasonal hypoxia in the northern Gulf of Mexico (nGoMex) is spatially complex facilitating opportunities to compare attributes of organisms likely to have experienced hypoxia with those that did not.  Such comparisons could elucidate potential effects of sub-lethal hypoxia exposure and reveal the extent to which some organisms display resilience to low oxygen conditions.  We compared condition factors of a demersal fish species, the Atlantic croaker (Micropogonias undulatus), collected within areas known to have experienced summertime hypoxia with those collected outside of these areas.  Fish collection occurred throughout the nGoMex in 2014 and 2015 during the fall NOAA SEAMAP research cruises. In addition to recording measurements of mass and length, the ratio of Mn:Ca in otoliths from a subset of individuals collected in the previously hypoxic areas was also measured to identify lifetime hypoxia exposure patterns.  Though the work is ongoing, we hypothesize Atlantic croaker as a mobile generalist feeder may display resilience in body condition to hypoxia exposure. This work will support future investigations into underlying mechanisms for coping with hypoxia including the potential for feeding niche shifts.