Food and initial size influence overwinter survival and condition of age-0 Atlantic cod

Details

• Journal Title:
  Canadian Journal of Fisheries and Aquatic Sciences
• Personal Author:
  Geissinger, Emilie A. ; Gregory, Robert S. ; Laurel, Benjamin J. ; Snelgrove, Paul V.R.
• NOAA Program & Office:
  NMFS (National Marine Fisheries Service) ; AFSC (Alaska Fisheries Science Center)
• Description:
  In subarctic Newfoundland, age-0 Atlantic cod (Gadus morhua) settle into coastal habitats in several summer–autumn pulses, resulting in broad length-frequency distributions before winter. Low winter temperatures and potential decreases in food availability pose challenges for young-of-year fish. To examine how size variation affects overwintering success under contrasting food scenarios, we conducted 114-day laboratory feeding trials at ambient overwinter sea temperatures, using demersal age-0 cod collected from Newman Sound, Newfoundland. We reared two size classes of juvenile cod under four daily ration levels (starvation, low, medium, high). We used Fulton’s K condition factor to interpret effects of food availability and fish size on survival over winter. We showed that small amounts of consumed food (<1% BW·day−1) maximized winter growth and condition potential of juvenile cod in Newfoundland waters. With no food, survival of small cod dropped below 80% on Day 47, whereas survival of large juveniles remained >80% until Day 74. Therefore, we expect higher survival of earlier settlers and increased size-selective mortality in age-0 cod during either unproductive or protracted winters, when food abundance is often low.
• Keywords:
  Atlantic Cod Infancy Mortality Atlantic Cod
• Source:
  Canadian Journal of Fisheries and Aquatic Sciences, 78(4)
• DOI:
  https://doi.org/10.1139/cjfas-2020-0142
• Document Type:
  Journal Article
• Place as Subject:
  Newfoundland and Labrador ; North Atlantic Ocean
• Rights Information:
  CC BY
• Compliance:
  Submitted
• Main Document Checksum:
  urn:sha256:24956eb072aa10952234acfbd0d911091ed08797eb8f24a7c2c3e3166bad4471
• Download URL:
  https://repository.library.noaa.gov/view/noaa/31465/noaa_31465_DS1.pdf
• File Type:
  [PDF - 2.26 MB ]