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

The relationship between the somatic growth rate (G) and feeding level (unfed, inter- mediate, 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°C, and 1 size-class of haddock (6.0 to 9.6 cm SL) at 8 and 12°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 2 range = 0.837 to 0.966). The growth rate and scope for growth were maximum at 12°C, whereas growth efficiency was greatest (26.0 to 32.2%) at temperatures between 5 and 8°C. Juvenile cod held at 15°C exhibited reduced rates and efficiencies of somatic growth compared to fish at other temper- atures. 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 2 = 0.716) and haddock (R 2 = 0.637). This relationship may be useful in estimating recent growth of age-0 juvenile cod and haddock in the field.

[1]  A. Tyler.  Rates of gastric emptying in young cod. , 1970 .

[2]  M. Peck,et al.  Energy losses due to routine and feeding metabolism in young-of-the-year juvenile Atlantic cod (Gadus morhua) , 2003 .

[3]  D. Conover,et al.  Effects of temperature, salinity, and fish size on growth and consumption of juvenile bluefish , 1995 .

[4]  J. Steele,et al.  An experimental study of the oxygen consumption, growth, and metabolism of the COD (Gadus Morhua L.) , 1972 .

[5]  D. Houlihan,et al.  Effects of nutritional regime on correlates of growth rate in juvenile Atlantic cod (Gadus morhua) : comparison of morphological and biochemical measurements , 1993 .

[6]  M. Wagner,et al.  Protocol and guide for estimating nucleic acids in larval fish using a fluorescence microplate reader , 2001 .

[7]  A. Folkvord,et al.  Effects of initial size distribution, day length, and feeding frequency on growth, survival, and cannibalism in juvenile Atlantic cod (Gadus morhua L.) , 1993 .

[8]  J. M. Elliott.  The Growth Rate of Brown Trout (Salmo trutta L.) Fed on Reduced Rations , 1975 .

[9]  J. R. Brett,et al.  6 – Physiological Energetics , 1979 .

[10]  John M. Green,et al.  Activity and movement patterns of juvenile Atlantic cod, Gadus morhua, in Conception Bay, Newfoundland, as determined by sonic telemetry , 1990 .

[11]  Temperature- and size-dependent growth of larval and early juvenile Atlantic cod (Gadus morhua): a comparative study of Norwegian coastal cod and northeast Arctic cod , 1999 .

[12]  Boutilier,et al.  Size and priority at settlement determine growth and competitive success of newly settled Atlantic cod , 1995 .

[13]  F. Page,et al.  Survival and Abundance of Young Atlantic Cod (Gadus morhua) and Haddock (Melanogrammus aeglefinus) as Indicators of Year-class Strength , 1989 .

[14]  A. Vethaak,et al.  Metabolism, food consumption and growth of plaice (Pleuronectes platessa) and flounder (Platichthys flesus) in relation to fish size and temperature , 1992 .

[15]  M. Jobling.  Food and growth relationships of the cod, Gadus morhua L., with special reference to Balsfjorden, north Norway , 1982 .

[16]  A. Hawkins,et al.  Growth and feeding of juvenile cod (Gadus morhua L.) , 1985 .

[17]  D. Staples,et al.  Influence of body size and food ration on the energy budget of rainbow trout Salmo gairdneri Richardson , 1976 .

[18]  Joseph A. Brown,et al.  Interpopulation differences in growth rates and food conversion efficiencies of young Grand Banks and Gulf of Maine Atlantic cod (Gadus morhua). , 2000 .

[19]  J. M. Elliott,et al.  The Growth Rate of Brown Trout (Salmo trutta L.) Fed on Maximum Rations , 1975 .

[20]  P. Pepin,et al.  The feeding, growth and behaviour of juvenile cod, Gadus morhua L., in cold environments , 1989 .

[21]  S. Campana.  Year-class strength and growth rate in young Atlantic cod Gadus morhua , 1996 .

[22]  F. Martin,et al.  The effect of starvation on RNA: DNA ratios and growth of larval striped bass, Morone saxatalis , 1985 .

[23]  J. Hislop,et al.  Further observations on the relation between food intake and growth of gadoids in captivity , 1978 .

[24]  B. Björnsson,et al.  The food-unlimited growth rate of Atlantic cod (Gadus morhua) , 2002 .

[25]  M. P. Fahay.  Essential fish habitat source document. Atlantic cod, Gadus morhua, life history and habitat characteristics , 1999 .

[26]  T. Targett,et al.  Effects of Ration Limitation and Low Temperature on Growth, Biochemical Condition, and Survival of Juvenile Summer Flounder from Two Atlantic Coast Nurseries , 1994 .

[27]  J. Rooker,et al.  Application of RNA : DNA ratios to evaluate the condition and growth of larval and juvenile red drum (Sciaenops ocellatus). , 1996 .

[28]  R. Mercaldo‐Allen,et al.  Evaluation of RNA concentration as an indicator of growth in young-of-the-year winter flounder Pseudopleuronectes americanus and tautog Tautoga onitis , 2002 .