34-2 Sat Jan 2 Evaluating methods to determine maximum oxygen consumption by Gulf killifish, Fundulus grandis Mullen, SC*; Knecht, KJ; Rees, BB; University of New Orleans; University of New Orleans; University of New Orleans brees@uno.edu
Metabolic rate is an essential feature of animal physiology and ecology. The rate of aerobic metabolism, as determined by oxygen consumption rate (MO2), is influenced by a variety of factors, including body size, temperature, and activity levels. Maximum aerobic metabolic rate (MMR) reflects the physiological capacity of an animal for oxygen extraction and utilization. As such, MMR is argued to be an important feature of an animal’s life history. For fish, MMR is frequently estimated as the peak MO2 immediately following an exhaustive chase, although several studies indicate that this value may underestimate MMR. Instead, MMR may be attained during sustained swimming or following ingestion of a large meal. In this study, we used intermittent-flow respirometry to quantify MO2 by the Gulf killifish, Fundulus grandis, following 3 min chase or ingestion of a meal representing 5-15% of the fish’s body mass. Peak post-prandial MO2 was marginally higher than MO2 after chasing. Interestingly, the highest MO2 recorded in these trials was frequently after changes in light-dark cycle, rather than after either chasing or feeding. Current experiments evaluate MO2 during sustained swimming. Taken together, our results suggest that MO2 after an exhaustive chase may underestimate MMR in F. grandis, as reported for other fish species.
