Metabolic responses to temperature in a sedentary reef fish, the bluebanded goby (Lythrypnus dalli, Gilbert)

As climate continues to change, many marine species will experience both an increase in average temperature and more extreme diel and seasonal fluctuations. Understanding how these variations in ocean temperature affect processes such as metabolism and energy consumption is important for many species, and may be particularly important for sedentary species that cannot make large-scale movements in response to changes in environmental conditions. We examined how metabolic rates and energetic demands responded to temperature in a temperate reef fish, the bluebanded goby (Lythrypnus dalli). Using respirometry, we estimated resting oxygen consumption (VO2) for 42 L. dalli individuals of varying sizes and calculated metabolic rates (MR) at three different temperatures (13 °C, 16 °C, and 20 °C). As predicted, VO2 and MR increased significantly with temperature and mass, but the rate of temperature-dependent increase in metabolism indicated a very high degree of thermal sensitivity for L. dalli (Q10 value for VO2 was 5.21 across the range of experimental temperatures). The mass-scaling exponent (b) was estimated to be 0.95 and aligned closely with other benthic species. Our results suggest that changes in temperature - especially those that occur over weeks and seasons - likely play a significant role in the ecology of these gobies. Long-term increases in seawater temperature will either necessitate an increase in foraging and consumption, or drive costly trade-offs between metabolism and processes such as growth and reproduction.