Showing papers in "Aquaculture in 1979"

TL;DR: Experiments showed that the steroid enriched diet had an acceptable shelf life and that the half life of oestradiol in rainbow trout was less than 12 h, and the usefulness of all-female stocks in commercial salmonid rearing operations is discussed.

TL;DR: In this paper, the effects of meal frequency on growth, feed efficiency, and body composition of trout were compared, and it was concluded that increasing the number of meals had no discernible effect, the efficiency of 30% glucose diet being the same in the various groups.

TL;DR: Diets containing both I. galbana and T. pseudonana invariably supported greater growth than diets consisting solely of either species, indicating synergism in the relative food values of the species.

TL;DR: A critical review of interspecific hybridization in salmonids is presented and the potentiality of hybrids for water management and fish farming is discussed.

TL;DR: Results indicate that Tilapia zillii requires about 35% protein in the diet for optimum growth while 30% for the maximum bodily protein deposition when casein is used as the sole source of protein.

TL;DR: Evidence is presented in this paper that Dunaliella tertiolecta is not toxic, and that its failure to support turbot larval growth is probably due to a deficiency of long-chain polyunsaturated fatty acids.

TL;DR: The study of the combined effects of light intensity and photoperiod confirmed the hypothesis that strong light intensities are lethal to newly hatched larvae (with no pigmentation).

TL;DR: Evidence was obtained to indicate that the rate of food consumption in this prawn is related to the energy content of the diet, which means that the protein level required to support maximum growth and optimum protein conversion efficiency are also energy dependent.

TL;DR: In seven out of 10 groups that received estradiol all fish resembled normal females when sampled at 4 months posthatch, while in fish treated with methyltestosterone the gonads resembled neither normal males nor normal females.

TL;DR: Fish growth rates of about 30% per month at high stocking densiteis were reached for Tilapia at a fish: water ratio of 1 : 4.6, indicating that a combination of biological water treatment and ozonation supports intensive fish culture in a closed aquaculture system.

TL;DR: Four species of bivalve molluscs were fed diets consisting of varying proportions of the yeast Candida utilis and the diatom Thalassiosira pseudonana and growth of soft tissue in Crassostrea virginica decreased with the amount of yeast in the diet.

TL;DR: Sixteen isocaloric diets varying only in the levels of ω3 and ω6 fatty acids were prepared, fed to duplicate groups of coho salmon for 14 weeks, and fish growth, feed conversion efficiency, fish mortality and fatty acid composition of fish phospholipids were determined.

TL;DR: Evidence is presented for the existence of a negative K-line relationship in P. merguiensis and food conversion efficiency declined with increasing weight and ration size but the relative loss in efficiency was least when rations were maintained near to the maximum.

TL;DR: Experiments on the live food requirements of cultured turbot larvae are described, and a mixture of six species of unicellular algae did not sustain early larvae, but the growth and survival of larvae fed with rotifers were considerably improved.

TL;DR: A sample of the all-male population of rainbow trout resulting from the dietary administration of 17α-methyltestosterone at a concentration of 3 mg/kg of food to juvenile fish during the 90-day period following “swim up” was grown to sexual maturity and indicates that in rainbow trout the male is heterogametic for sex.

TL;DR: Interaction between diet fed and family was found close to significance for weight and relative growth rate, and significant for length and condition factor, indicating that prospects for selectively breeding strains of rainbow trout specifically better able to utilize protein are promising.

TL;DR: The main reason for the retardation in fish growth and the reduction of protein utilization when soyabean meal content is increased in the diets, seemed to be that the destruction of anti-nutritional factors by the heat processing of the meal was only partial.

TL;DR: Investigations revealed that microencapsulated semi-defined diets may be used to determine the nutritional requirements of Penaeus larvae, and experiments showed that survival rates of 50% to post-larva were possible.

TL;DR: A female milkfish, captured at sea, was injected with two hormonal injections of acetone-dried salmon pituitary powder and human chorionic gonadotropin, plus Vitamin B complex, and produced 128,000 ripe eggs, with the highest larval survival rate obtained from different experimental groups was 46.8%.

TL;DR: A bath treatment of 300 p.p.m.

TL;DR: Significant correlation coefficients between different body components enabled calculation of regression equations by which biologically important parameters, such as protein, fat, ash and energy, can be estimated from a relatively simple moisture determination.

TL;DR: In all cases true digestibility was slightly increased compared with apparent protein digestibility, and that of the whole diet decreased significantly with increasing carbohydrate and decreasing protein level in the diet.

TL;DR: It is anticipated that induction by eyestalk ablation could allow a considerable extension of the growing season and of the area suitable for culture.

TL;DR: The test proteins were well digested, assimilation values ranging from 80.3% (HM diet) to 96.6% (PY diet), and the NPU's and BV's calculated from body analysis data were respectively for each protein.

TL;DR: It is suggested that this and the tolerance shown by the fish, which is higher than is generally accepted for fish in high density culture, may be due to the clean environment in which the fish were held while under test.

TL;DR: Oral administration of 17β-oestradiol at 20 mg/kg diet for a period from 0 to 60 days following “swim-up” resulted in the sex reversal of male brook trout and the production of essentially all-female populations.

TL;DR: Results show that a dietary level of 40% protein was required by milkfish fry for maximum growth, efficient feed conversion and high survival rate.

TL;DR: The results suggest that 10° C is optimal for incubating Atlantic salmon eggs, and Mortality rate during the first 6 weeks of feeding was correlated with mortality during earlier development.

TL;DR: Parasitic infections occur in sea cultured Sparus aurata and Dicentrarchus labrax in France and Investigations indicate the presence of parasitic protozoans, monogeneans and copepods in these fish.

TL;DR: Chemical treatments were used to produce sex-reversed female (genetic male) Tilapia aurea, which can be bred to produce monosex offspring, and Diethylstilbestrol was as potent as EE in comparable CA treatments.