Aquatic Sciences Meeting, Albuquerque 2001

SS35 Biological and Ecological Responses to Low Oxygen in Constant and Fluctuating Environments (Spatial and Temporal Connections)

Date: Thursday, February 15, 2001, Time: 12:00:00 PM

Location: La Cienega

Chabot, D, , Institut Maurice-Lamontagne, Fisheries & Oceans Canada, Mont-Joli, Canada, ChabotD@dfo-mpo.gc.ca

Dutil, J, D, Institut Maurice-Lamontagne, Fisheries & Oceans Canada, Mont-Joli, Canada, DutilJD@dfo-mpo.gc.ca

REDUCED FOOD INGESTION AND GROWTH OF ATLANTIC COD (GADUS MORHUA) IN CHRONIC HYPOXIA

Oxygen levels range from 70% down to 30% saturation or less in waters deeper than 175 m in the Gulf of St. Lawrence. The potential impact of hypoxia on Atlantic cod was investigated. In a first experiment (84 days, 3 meals per week), cod were raised under 6 oxygen treatments between 45 and 93% saturation. Growth and food ingestion were limited by oxygen below 70% saturation. In a second experiment (56 days), we varied meal frequency (1, 3, and 7 meals per week) for cod held at two regimes of dissolved oxygen (45 and 90% saturation). In normoxia, growth was significantly reduced at 1 meal per week compared to 3 and 7 meals. In hypoxia, however, there was no difference in growth between the 3 feeding frequencies. At 1 meal per week, growth was equally poor at both oxygen levels. At 3 and 7 meals per week, growth was faster in normoxia than in hypoxia, although this was significant only at the highest feeding frequency. In both experiments, food consumption explained practically all of the variability in growth rate.

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Aquatic Sciences Meeting, Albuquerque 2001

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