Gulf of Alaska | Fishes and Fish Habitats
Trophic life histories of sablefish from birth through maturation as inferred by eye lens stable isotopes Presenter: Matthew Rogers , matthew.rogers@noaa.gov, NOAA Fisheries Katy Echave , katy.echave@noaa.gov Kevin Siwicke , kevin.siwicke@noaa.gov Todd Miller , todd.miller@noaa.gov, Ted Stevens Marine Research Institute (TSMRI), NOAA Alaska Fisheries Science Center Wil Licht , wil.licht@noaa.gov, Ted Stevens Marine Research Institute (TSMRI), Azura Consulting, Azura Consulting Sablefish ( Anoplopoma fmbria ) are a commercially important catch in Alaska, yet we do not have a full understanding of the mechanisms underpinning recruitment in this species. The trophic life history of sablefish may play an important role in growth and survival and may lead to strong recruiting classes or differences in fitness across individuals. Sablefish are opportunistic feeders and are known to prey on many different species of forage fish as well as squid, euphausiids, and jellyfish. In this study we explore the first use of stable isotope analysis in sequentially grown eye lens layers to infer the trophic life history of individual sablefish from birth through maturation. The eye lens is formed in layers which are inert after synthesis and store dietary stable isotopic information over the entire period of fish growth. We sampled eye lenses from sablefish caught in the annual NOAA longline survey in the Gulf of Alaska. Individual eye lenses were dissected into as many as ~40 layers and the individual layers were analyzed for their stable isotope signatures. We found substantial variability in eye lens isotope patterns among the individuals surveyed, particularly in carbon stable isotope signatures. Further work is in progress to experimentally determine trophic discrimination factors relating diet to eye lens isotopic signatures. Eye lens carbon isotope data patterns in conjunction with trophic discrimination factors may reveal differing timing of ontogenetic shifts in diet or habitat use and may be useful in helping to determine which trophic life history patterns lead to greater fitness and survival.
Alaska Marine Science Symposium 2023 200
Made with FlippingBook flipbook maker