The relationship between the temperature requirements of some fish species, using published data for growth optima, final preferences and lethal limits were examined. A good correlation was found it is suggested that established gives a estimate promoting maximum growth. Determinations preferenda are easily conducted in laboratory could therefore be used to give rapid assessments optimum temperatures potential culture species. practical application such measurements discussed.

Abstract The form and structure of fish otoliths are species specific, allowing them to be used as an aid in identification prey consumed by piscivores. Otholith length-fish length relationships can have application the estimation size squid, but, because relatively rapidly attacked acidic solutions, these not routinely for taken marine mammals, birds predatory fishes. Evidence from recent physiological studies gastrointestinal motility suggests that indigestible material (skeletal fragments...

Abstract Cannibalism is a frequent phenomenon in fish, especially culture environments where fish are unable to escape predation via habitat segregation or migration. Not all cultured species start exhibit cannibalism at the same age size, nor equally intense different life stages. Predator prey size ratios vary substantially between and stages, chiefly because governed by gape limitations allometric growth of mouthparts. The development sense organs, hard body parts, swimming capacities...

Juvenile Arctic charr responded to a change from restricted satiation feeding by showing growth spurt (compensatory growth). During this period of rapid the fish became hyper‐phagic and in days immediately following transfer showed improved food conversion efficiency compared their counterparts raised on liberal regime. Tissue (liver muscle) nucleic acid concentrations were influenced regime, RNA : DNA ratios low both starved those fed rations. Following feeding, tissue rapidly restored...

Compensatory growth responses of rainbow trout Oncorhynchus mykiss were studied by examining food intake and individual fish held within groups that switched between regimes involved full restricted feeding. Restricted feeding led to marked interindividual variability in intake, probably as a result the establishment hierarchies. This disparity acquisition was reflected highly heterogeneous amongst fed low rations. When transferred from rations, they became hyperphagic displayed high rates...

The rate of oxygen consumption plaice increases after feeding and declines to a resting level 24–72 h. maximum increase corresponds which is approximately twice the consumption. This Specific Dynamic Action (SDA) in magnitude with food intake. greatest high protein content diets. duration SDA effect reduced temperature percentage diet.

The literature relating to gastric evacuation in fishes is reviewed and, where appropriate, the data re‐analysed and fitted mathematical models of emptying. A volume dependent model emptying suggested as being most appropriate for species are adequately described by an equation form d V /d T = ‐ c 0.5 . equations then incorporated into estimation daily food consumption accuracy predictions tested.

The effects of long-term moderate exercise on the behaviour and food intake – growth relationship individually marked Arctic charr, Salvelinus alpinus L., were examined. Direct monitoring individual fish was carried out using an X-radiographic method. Growth (weight gain) significantly improved with increasing swimming speed, a maximum specific rate obtained at speed approximately 1.75 body lengths/s. appeared to be suppressed by high levels aggressive interactions, increase in caused...

The relationship between growth rate and fish size is described by the equation log e G w = a —0·4 W, where specific W weight. Since intercept (a) represents of unit size, presents method allowing comparison data from experiments involving different sizes. application demonstrated examining effects environmental temperature on rates cod, Gadus morhua , it suggested that optimum for cod 13–15° C.

Juvenile Arctic charr, Salvelinus alpinus , subjected to either food deprivation or restricted feeding showed reductions in relative sizes of both liver and viscera. With deprivation, percentage lipid decreased water increased the eviscerated carcass, which is agreement with findings for several other fish species. Following transfer from a satiation regime, viscera levels exceeding those fed continuously satiation. At end experiment content restricted‐satiation was higher than These...

Of the hypotheses proposed to explain specific dynamic action (SDA), it is suggested that ‘protein synthesis/growth’ theory offers best basis for further research. In light of this, relationships between rates protein synthesis and metabolic are examined. Both which depressed with increasing periods starvation there appears be a link thyroid activity. SDA may represent short‐term increase in turnover following feeding process possibly regulated via plasma levels hormones.

Proximate analysis of the body tissues plaice showed that fat was major storage reserve utilized during starvation. Although liver and gut were much depleted period fast they contributed only a small proportion metabolizable energy. Atrophy led to reductions in motor activity but ability digest absorb nutrients not impaired. Assessments energy utilization using proximate calculations from ammonia quotient determinations are compared show latter part 20–25% derived protein catabolism.