F 17
KUNGVANKIJ, P., TIRO, L.B., PUDADERA, B.P. and I. O.
POTESTAS
Induced spawning and larval rearing of grouper
(Epinephelus salmoides, Maxwell).
1986 15 pp
NACA, NACA/WP/86/47
Broodstock of grouper (Epinephelus salmoides) were induced to spawn by hormonal induction. The hormones used for this experiment were HCG+ pituitary gland (PG) and LRH-a. The results showed that at the dosages of 500 IU HCG + 3 mg of PG per kg of fish for first injection and 1000 IU HCG + 3 mg of PG per kg of fish at the final injection at an interval of 24 hours, the treated fish spawned naturally in a spawning tank 12 hours after the final injection. At lower dosages of 500 IU HCG + 3 mg PG at 12 hours intervals or 500 IU PCG + 3 mg PG at 24 hours intervals or using 10 mg LRH-a at 12 hours intervals, the eggs can be artificially fertilized only by stripping. The larval rearing experiment was conducted in a 250 litre fiberglass tank at the stocking density of 2500 larvae per tank. Feeds used in this experiment were: (a) Isochysis + sea urchin eggs; (b) Isochysis + Brachionus; and (c) Tetraselmis + Brachionus. The experiment results showed that newly hatched larvae fed with Isochrysis mixed with the sea urchin eggs and then switched to Brachionus on day 10 gave the best survival rate (9% at day 30).
F 18
BESSIE, O.
Characteristics of bacteria isolated from diseased
groupers, Epinephelus salmoides.
1988 10 pp
Aquaculture, 73, 7–17
Groupers, Epinephelus salmoides, cultured in floating cages are susceptible to bacterial disease with external sign such as hemorrhaging skin ulcerations, tail rot and fin rot. Bacteria isolated from the diseased fish are mainly short, asporogenous rods which show oxidative and fermentative metabolism of carbohydrates producing acid but not gas, are oxidase positive and sensitive to the vidriostatic compound 0/129 (2,4-diamino-6,7-pteridine). These bacteria can be classified into four main clusters based on their biochemical and physiological characteristics. Bacteria from cluster 1 consisted of two strains, both of which formed large, blue-green colonies on Thiousulphate Citrate Bile Salts Sucrose (TCBS) agar. Bacteria from cluster 2, formed large, yellow colonies on TCBS agar which later changed to green in color when incubated for more than 48 h. The bacteria from these two clusters are pathogenic to tilapias and groupers and show characteristics which are similar to Vibrio-like bacteria. Bacteria from the other clusters are generally secondary invaders which enter the fish once the disease has set in.
F 19
SENG, L.T. and W.S. YONG
Parasites of wild and diseased juvenile golden
snapper, Lutjanus johni (Bloch), in floating cages in
Penang, Malaysia.
1987 8 pp
Asian Fisheries Science 1, 83–90
A total of 148 wild healthy juvenile snapper (Lutjanus johni) from the Middle Bank, and 197 diseased ones from floating cages in Penang, Malaysia, were examined for parasites. Seventeen species of parasites were recovered. The most abundant parasite was the monogenean, Haliotrema johni, found in all samples of healthy and diseased fish. The densities of this monogenean in diseased fish (up to a mean of 314.1) were an order of magnitude higher than that of the healthy ones (28.9). One of the major factors that contribute to the observed disease outbreak was probably the high density of the monogenean. In the diseased fish, areas near the nostrils, above and below the eyes, and sides of the operculum were without skin and scales. The exposed areas were reddish. Haemorrhagic caudal fin rot, typical symptoms of vibriosis were also observed in many of the diseased fishes.
F 23
LEE, C.S., TAMARU, C.S. and C.D. KELLEY
The cost and effectiveness of CPH, HCG and LHRH-a on
the induced spawning of grey mullet, Mugil cephalus.
1988 7 pp
Aquaculture, 73, 341–347
Two hormone injections a primer and a resolver, were used to induce spawning in grey mullet. Combinations of carp pituitary homogenate (CPH), human chorionic gonadotropin (HCG) and luteinizing hormone-releasing hormone analogue (LHRH-a), each used as a primer or resolved were tested in 60 spawning attempts. Another six fish received saline injections and served as sham controls. The cost and the response, in terms of spawning and fertilization rates, of easy combination were evaluated. The CPH/LHRH-a treatment is the most reliable and cost-effective method. HCG can replace CPH in this treatment, but the cost is higher and the response poorer. The HCG/LHRH-a treatment can, however, be used for research purposes.
F 24
LAJONCHERE, L.A.,ARRITOLA,J.B., AVERHOFF, O.L. and
S.D. BELLIDO
Positive results of induced spawning and larval
rearing experiments with Mugil liza Val., a grey
mullet from Cuban waters.
1988 6 pp
Aquaculture, 73, 349–355
Induced spawning and larval rearing experiments were carried out with Mugil liza at Tunas de Zaza, Cuba. Of the 39 females treated with hormones, viable eggs and larvae were obtained from 9 females with natural or artificial fertilization. The best results were obtained with mullet pituitary homogenate (15 mg/kg), HCG with mullet pituitary homogenate (27–54 I.U./g with 18–48 mg/kg), HCG alone (53.1–60 I.U./g) and HCG with carp pituitary homogenate (12–41 I.U./g with 29.2–48 mg/kg) in that order, administered in three injections at 24-h intervals.
F 25
MATSUYAMA, M., ADACHI, S., NAGAHAMA, Y. and S.
MATSUURA
Diurnal rhythm of oocyte development and plasma
steroid hormone levels in the female red sea bream,
Pagrus major, during the spawning season.
1988 5 pp
Aquaculture, 73, 357–372
Diurnal maturation rhythm in the female red sea bream, Pagrus major, which spawns every day during the spawning season and has an asynchronous-type ovary containing oocytes at various stages of development, was studied by histological investigation of the ovary. Plasma levels of estradiol-17B and testosterone corresponding to the ovarian maturation rhythm were also investigated. The fish had a diurnal ovarian maturation rhythm in which the most advanced oocytes in the ovary finished germinal vesicle breakdown at 07.00 h, arrived at a mature state at 10.00 h. and ovulation began at 13.00 h. Spawning mainly occurred between 18.00 and 19.00 h. Plasma estradiol-17B levels reached a peak of about 1200 pg/ml in fish with pre-mature stage oocytes at 07.00 h, followed by a sharp drop in ovulated fish at 13.00 h (to about 200 pg/ml); the levels showed a tendency to increase from the time of postovulation to the next germinal vesicle breakdown. Testosterone levels decreased (to about 20 pg/ml) at ovulation time (13.00 h.) in parallel with the estradiol-17B levels, but were largely unchanged (70–110 pg/ml) throughout the rest of the ovarian maturation cycle. These results are discussed in relation to other studies on the role of these steroid hormones responsible for the ovarian maturation of teleosts.
F 45
INFOFISH
Markets for reef fish in Singapore and Hong Kong.
1989 3 pp
Infofish International 1/89, 17–19
Apart from Japan, Singapore and Hong Kong are the major Asian markets for reef fish. The vibrant trade in these species testifies to their enormous popularity in many Asian countries.
F 46
SAMUELSEN, O.B., ERVIK, A. and E. SOLHEIM
A qualitative and quantitative analysis of the
sediment gas and diethylether extract of the dediment
from salmon farms.
1988 9 pp
Aquaculture, 74, 277–285
A quantitative glc/ms analysis of the diethylether extract of the sediment under Norwegian salmon farms showed that in addition to numerous fatty acids, metabolites typical of anaerobic microbiological activity (p-cresol, benzoic acid, 3-phenylpropionic acid, phenylacetic acid and methylindole) are present in large amounts. The gas developed in the sediment consisted of methane (70–90%), carbon dioxide (10–30%) and hydrogen sulfide (1–2%), when sampled just above the sediment. Even though H2S and Co2 are very soluble in seawater, both were still present in the gas sampled 9 m above the bottom.
F 47
ISAKSSON, A.
Salmon Ranching: a world review.
1988 33 pp
Aquaculture, 75, 1–33
The classification of salmon ranching within the field of aquaculture and how it can be distinguished from public enhancement practices on genetic and biological grounds are discussed. The review provides a brief historical account of salmon ranching in the Pacific and the Atlantic, emphasizing major technological innovations. The possibilities of improving ranching performance through selective breeding and manipulation of the rearing cycle are great. A survey of the literature on salmon ranching seems to indicate that the most profitable commercial operations are those using species with a short freshwater rearing period, such as pink and chum salmon. These operations occur mostly in Japan, the USSR and Alaska and support large-scale commercial fisheries.
F 48
WEMBIAO, Z., JIONGHUA, P. and L. WENSHENG
Culture of catfish in China.
1988 10 pp
Aquaculture, 75, 35–44
The culture of catfish in China began in the mid-1950s. Today Clarias fuscus, C. batrachus, C. lazera and their hybrids are commonly cultivated. It became a profitable undertaking with low investment, low cost, and quick results. The propagation areas are mainly in South China. In this paper, recently developed methods and techniques used in artificial propagation, rearing of fingerlings, and adult fish culture for several catfishes are described.
F 49
BOMBEO-TUBURAN, I.
The effects of stunting on growth, survival, and net
production of milkfish (Chanos chanos, Forsskal).
1988 7 pp
Aquaculture, 75, 97–103
The seasonal abundance of milkfish fry in the Philippines has led to the practice of buying a sufficient supply during the peak season to compensate for the shortage during slack periods. Fry that are not immediately grown out are crowded and stunted in transition ponds until they are transferred to rearing ponds. Milkfish farmers believe that stunted fingerlings grow faster than newly grown ones and therefore yield extra croppings. To assess the efficiency of production schemes, stunted and nonstunted milkfish fingerlings were cultured in twelve 144-m2 ponds for a 3-month period. The treatments employed were: Treatment I, 2-month-old fingerlings; Treatment II, 3-month-old fingerlings; and Treatment III, 6-month-old fingerlings, with the initial weights of 3.3 g, 7.8 g, and 43.1 g, respectively. Survival, net production, cumulative and monthly weight gains did not differ significantly (P>0.05) among the three treatments. The results, indicate that stunting did not illicit a significant increase, nor did it adversely affect the growth, survival, and net production of milkfish in a straight culture system. Stunting can therefore be practised by farmers to provide an adequate supply of fingerlings for year-round operation.
F 50
VIOLA, S., ARIELI, Y. and G. ZOHAR
Animal-protein-free feeds for hybrid tilapia
(Oreochromis niloticus × O. aureus) in intensive
culture.
1988 10 pp
Aquaculture, 75, 115–125
Growth trials were carried out with tilapia in experimental ponds to develop an animal-protein-free diet of nutritive value equal to a standard commercial fishmeal feed. A diet based on soybean meal and supplemented with amino acids, oil and di-calcium phosphate resulted in growth performances and body compositions equal to those on a fish-meal diet. Successive withdrawal of the supplements results in a final fish-meal-free diet, with 3% di-calcium phosphate and 2% oil as the only supplements necessary to achieve growth performances equal to those obtained with a fully supplemented diet.
F 51
VAN WEERD, J.H., SUKKEL, M. and C.J.J. RICHTER
An analysis of sex stimuli enhancing ovarian growth
in pubertal African catfish, Clarias gariepinus.
1988 10 pp
Aquaculture, 75, 181–191
Ovarian growth in pubertal African catfish was followed during a 100-day period. Different combinations of male sensory stimuli resulted in three distinct levels of ovarian development. A basic level (ovarina weight 5.3–7.5 g; GSI 1.9–2.7%) was reached in controls (no contact with males) and in females having visual and auditory contact with males. An intermediate level (ovarian weight 11 g; GSI 4%) was reached if olfactory contact with males was possible. A maximum level (ovarian weight nearly 20 g; GSI 7.3%) resulted from unlimited contact between the two sexes. The question is discussed whether the difference between maximum and intermediate levels of ovarian growth should be ascribed to a better water quality due to experimental conditions rather than to the presence of male tactile stimuli. The possible existence of male primer pheromones responsible for the observed stimulation of ovarian growth in pubertal African catfish by enhancing vitellogenesis is also discussed.
F 52
VIJAYAN, M.M and J.L. LEATHERLAND
Effects of stocking density on the growth and stressresponse
in brook charr, Salvelinus fontinalis.
1988 11 pp
Aquaculture, 75, 159–170
In brook charr (Salvelinus fontinalis) stocked at three different densities (30, 60 and 120 kg/m3) growth rate, feed consumption and feed conversion efficiency decreased significantly with stocking density. Plasma cortisol, T4 and glucose levels showed a significant decrease with increased stocking density at the end of the first 30-day rearing period, while plasma protein levels were significantly lower with increased stocking density after the second 30-day rearing period. However, plasma T3 levels, T3:T4 ratios, liver glycogen content, hepatosomatic index and splenosomatic index showed no significant differences over the 60-day rearing period.
