Tissue-dependent stable isotope analysis of Arctic sculpin (Myoxocephalus scorpioides) to assess local seasonal variability in prey availability.

Mark Bryce Barton, Florida International University, Biology, North Miami, FL, United States, Kevin M Boswell, Florida International University, Department of Biological Sciences, North Miami, FL, United States, Brenda Norcross, University of Alaska Fairbanks Institute of Marine Science, School of Fisheries and Ocean Sciences, Fairbanks, AK, United States, JJ Vollenweider, NMFS/NOAA, Alaska Fisheries Science Center, Juneau, AK, United States and Ron Heintz, NOAA NMFS, Alaska Fisheries Science Center, Juneau, AK, United States
Nearshore Arctic marine ecosystems face imminent threats from climate change and increasing anthropogenic impacts. It is likely that the associated environmental changes will affect the abundances of different prey resources as tolerable ranges expand, contract, and shift; but it is unclear how this will affect the predators of the Arctic nearshore. Stable isotope analysis of more charismatic and well-studied plankton and nekton species (I.e. Krill, Arctic cod and capelin) are not likely to indicate site-specific temporal changes in prey resources due to their low site fidelity and ability to follow preferred prey types across relatively broad spatial scales. The ubiquitous distribution, high site-fidelity, and opportunistic feeding of Arctic sculpin (Myoxocephalus scorpioides) make it an ideal candidate as a bio-indicator to examine site-specific effects of environmental change on prey availability. Juvenile M. scorpioides (n=81) were used in a growth and feeding experiment to determine stable carbon and nitrogen isotope incorporation rates in liver, muscle and fin tissues. We use results from the experiments to give temporal context to isotopic shifts in tissues from M. scorpioides collected during the summers of 2013 and 2014 from the Point Barrow, AK region to examine the natural variability in prey resources across rapidly changing environmental conditions associated with land-fast ice break-up. In order to make large scale predictions about changes in prey resources we must first understand this small-scale seasonal variability and the environmental factors that drive these changes.