Effects of food consumption and temperature on growth rate and biochemical-based indicators of growth in early juvenile atlantic cod Gadus morhua and haddock Melanogrammus aeglefinus

• Published in: Marine ecology. Progress series (Halstenbek) 2003-01, Vol.251, p.233-243
• Main Authors: PECK, Myron A, BUCKLEY, Lawrence J, CALDARONE, Elaine M, BENGTSON, David A
• Format: Article
• Language: English
• Subjects: Agnatha. Pisces; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Autoecology; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Gadus morhua; Marine; Melanogrammus aeglefinus; Protozoa. Invertebrata; Vertebrata
• ISSN: 0171-8630; 1616-1599
• DOI: 10.3354/meps251233

The relationship between the somatic growth rate (G) and feeding level (unfed, intermediate, and maximum rations) of age-0 juvenile cod Gadus morhua and haddock Melanogrammus aeglefinus was quantified at different temperatures. Laboratory trials were conducted using 2 size classes of cod (3.6 to 5.6 cm standard length [SL], and 8.1 to 12.4 cm SL) at 5, 8, 12, and 15 degree C, and 1 size-class of haddock (6.0 to 9.6 cm SL) at 8 and 12 degree C. The shape of the growth-feeding relationship was well described by a 3-parameter asymptotic function for cod and by a linear function for haddock (R super(2) range = 0.837 to 0.966). The growth rate and scope for growth were maximum at 12 degree C, whereas growth efficiency was greatest (26.0 to 32.2%) at temperatures between 5 and 8 degree C. Juvenile cod held at 15 degree C exhibited reduced rates and efficiencies of somatic growth compared to fish at other temperatures. Biochemical-based growth indicators for age-0 juveniles were calibrated from measurements of the amounts of RNA, DNA, and protein in white muscle samples. A multiple linear regression using RNA:DNA and temperature as independent variables explained a significant portion of the variability observed in G of juvenile cod (R super(2) = 0.716) and haddock (R super(2) = 0.637). This relationship may be useful in estimating recent growth of age-0 juvenile cod and haddock in the field.