Effects of temperature, prey type and prey size on gastric evacuation in small cod and whiting

Authors

  • S. Singh-Renton,

    1. CFRAMP, Tyrell Street, St Vincent and the Grenadines, West Indies
    Search for more papers by this author
  • P. J. Bromley

    Corresponding author
    1. Ministry of Agriculture, Fisheries and Food, Directorate of Fisheries Research, Fisheries Laboratory, Lowestoft, Suffolk, NR33 0HT, U.K.
      *Author to whom correspondence should be addressed. Tel.:+44 (0)1502 562244; fax:+44 (0)1502 513865.
    Search for more papers by this author

*Author to whom correspondence should be addressed. Tel.:+44 (0)1502 562244; fax:+44 (0)1502 513865.

Abstract

Gastric lavage was used to investigate the effects of temperature, prey type and prey size on gastric evacuation in small cod Gadus morhua and whiting Merlangius merlangus. The fish were fed to satiation and subsequently the stomach contents were sampled to determine the rate at which food was evacuated. Satiation meal size was positively related to temperature and differed between prey types. The gastric evacuation rate (GER) also tended to increase with temperature and varied with prey type. GER at temperatures of 11.3–12.7° C averaged 1.5–1.7 times higher than at 6–9.5° C. There was no significant difference (P>0.05) in the evacuation of lugworm Arenicola marina, sandeel Ammodytes spp., and herring Clupea harengus, but the GER of brown shrimp Crangon vulgaris was much slower (P<0.05). No significant changes in GER were observed when fish were fed on three different size groups of either herring or brown shrimp. In whiting, there was no significant difference in the GER of individual herring or brown shrimp when they were fed as single species meals or incorporated in meals containing a mixture of prey species.

Ancillary