IJA Volume 56, Issue 2, 2004

Permanent URI for this collection


Recent Submissions

Now showing 1 - 8 of 8
  • Item
    A Preliminary Study On The Effects Of Salinity On Egg Development Of European Squid (Loligo Vulgaris Lamarck, 1798)
    (Israeli Journal of Aquaculture - BAMIGDEH, 2004) Sen, Halil
    The effects of salinity on the development and incubation of European squid (Loligo vulgaris, Lamarck, 1798) eggs were investigated from December 2001 to March 2002. The egg capsules were incubated in 37‰, 34‰, 31‰, 28‰, and 0‰ salinity without any acclimation process. Mean temperature was 12±2.0°C. Illumination was maintained at 1.5 lux at the water surface. Full embryonic development and hatching were observed after 64-76 and 66-76 days at 37‰ and 34‰ salinity, respectively. Hatching rates were estimated as 88.5% at 37‰ and 60% at 34‰. In salinity below 34‰, the eggs died at very early stages. Average dorsal mantle lengths of the new hatchlings were 2.53±0.08 mm at 37‰ and 2.48±0.11 mm at 34‰.
  • Item
    Amino Acid Profiles In The Midgut, Ovary, Developing Eggs And Zoes Of The Mud Crab, Scylla Serrata
    (Israeli Journal of Aquaculture - BAMIGDEH, 2004) Peñaflorida, Veronica Dy
    Culture of the mud crab, Scylla serrata, is beset by low and inconsistent survival of larvae in spite of the high fecundity of crab breeders. The nutrition of the embryo and pre-feeding zoea depends on what is stored in the egg. The protein and free amino acid contents of the midgut gland, ovary, eggs, pre-feeding zoea, live food and a maintenance diet for broodstock were analyzed by HPLC. The maintenance diet had lower arginine, histidine, methionine, threonine and tryptophan than the ovary and egg. The midgut had higher phenylalanine and valine and lower leucine, methionine and tryptophan than the ovary. Amino acid profiles in the ovary, egg and zoea showed that methionine was highest in the ovary and leucine was highest in the zoea. Low val- ues were observed for isoleucine and valine in ovary, arginine in egg, methionine and pheny- lalanine in zoea. When live foods were compared to zoea, histidine in Brachionus, leucine and tryptophan in Artemia, and arginine, leucine and valine in Acartia were low. Essential free amino acids in fertilized eggs were 2.5 times higher than in unfertilized eggs. Arginine, histidine, lysine, methionine, tyrosine and threonine decreased with egg embryogenesis, suggesting that these are the major free amino acids utilized as the egg develops. Information on egg and zoea amino acids can be used to predict viable crab eggs while information on amino acid profiles in the ovary, egg and zoea can be used to develop broodstock diets. Identification of limiting amino acids in live foods can be used to develop larvae diets.
  • Item
    Reproductive Biology Of The Shi Drum (Umbrina Cirrosa) In Captivity And Induction Of Spawning Using Gnrha
    (Israeli Journal of Aquaculture - BAMIGDEH, 2004) Mylonas, Constantinos C. ; Kyriakou, Yiannos ; Sigelaki, Irini ; Georgiou, Georgios ; Stephanou, Daphne ; Divanach, Pascal
    The reproductive biology of the shi drum (Umbrina cirrosa) in culture was histologically exam- ined and sperm quality was monitored during an entire reproductive period. Already in April, the ovary contained oocytes in all stages of maturation, from primary oocytes to full vitellogenesis, as expected from a group-synchronous multiple-batch spawning fish. Vitellogenesis of the first batch of oocytes occurred very rapidly and their mean diameter (500 μm) did not increase sig- nificantly (p>0.05) as the reproductive period proceeded. The spermiation index peaked in May- June, but fish never produced copious amounts of milt upon abdominal pressure. The sperma- tozoa motility percentage remained unchanged throughout the spawning season (80%) and a significant percentage (40%) maintained viability after overnight storage at 4°C. Sperm density and motility duration increased during the reproductive period and varied 13-26 x109 spermato- zoa/ml and 26-40 s, respectively. Spontaneous spawning was not observed during the two-year study. Injection of post-vitellogenic females with an agonist of gonadotropin-releasing hormone (GnRHa) was successful in inducing a single spawning after two days, with fertilization, hatch- ing and 4-day larval survival rates of 65%, 42-76% and 46-80%, respectively. The results under- line the failure of female shi drum in culture to undergo final oocyte maturation and, although GnRHa injection was effective in inducing spawning of viable eggs, multiple treatments did not induce multiple spawns, as was expected from fish with multiple-batch group-synchronous ovar- ian biology.
  • Item
    Effects Of Feeding Frequency On Growth And Fecundity In An Ornamental Fish, Betta Splendens (Regan)
    (Israeli Journal of Aquaculture - BAMIGDEH, 2004)
    Experiments were performed to investigate the influence of feeding frequency on growth, gonad weight and fecundity in an ornamental fish, Betta splendens. Five groups of 30-day-old juveniles (0.045±0.01 g; 14.43±2.2 mm) were fed either one meal in three days, one meal in two days, one meal per day, two meals per day or three meals per day for 77 days. Mean body length and weight increased linearly in all groups. However, the feeding, growth and fecundity rates increased with feeding frequency up to two meals a day, thereafter they declined. Fish fed once in three days consumed only 266 mg feed (dry weight) that was converted into 61 mg flesh (dry weight). Fish fed once in two days consumed 384 mg and gained 116 mg flesh. For fish fed once a day, 543 mg were consumed and converted to 175 mg flesh. For those fed twice a day, 1000 mg feed produced 279 mg flesh and for those fed three times a day, 886 mg food produced 242 mg flesh. The growth rate was significantly and drastically lower in all groups after spawning began, perhaps due to diversion of assimilated food energy for egg production. The gonad developed significantly (p<0.05) earlier in fish given at least one meal per day and weighed 85.5, 158 and 246.5 mg (wet weight) in fish fed once, twice and three times per day, respectively, on day 35 while it weighed only 56 and 93.5 mg on day 63 in fish fed once in three or two days, respectively. A similar trend was noted in the gonadosomatic index. Female B. splendens laid 274 and 454 eggs in groups fed once in three or two days, and 1833, 2202 and 632 eggs in groups fed once, twice or three times a day, respectively. Feeding three times a day resulted in total mortality of the spawners during the third spawn. Two meals a day elicited the maximum growth and reproductive performance and hence is considered optimal for B. splendens.
  • Item
    Economic Evaluation Of Multiple Research Innovations On An Eel Farm
    (Israeli Journal of Aquaculture - BAMIGDEH, 2004) Din, Gregory Yom ; Zugman, Zinaida ; Degani, Gad
    An approach for evaluating multiple innovations of an aquaculture farm is proposed, based on a model of induced innovations, supplemented with a bio-economic table for the calculation of pro- duction function. Data gathered from a model eel farm were used as an example. The proposed approach enables evaluating each innovation to determine which is the most profitable.
  • Item
    Total Aromatic Amino Acid Requirement Of The Indian Major Carp, Cirrhinus Mrigala (Hamilton-Buchanan)
    (Israeli Journal of Aquaculture - BAMIGDEH, 2004) Benakappa, S. ; Varghese, T.J.
    Quantification of the essential amino acid requirements of a species is required for formulating optimal diets for cultivated fish. In this study, crystalline L-phenylalanine was used to determine the quantitative phenylalanine requirement of juvenile Cirrhinus mrigala. Test diets (40% crude protein) contained vitamin-free casein and gelatin supplemented with crystalline L-amino acids to provide an amino acid profile similar to C. mrigala muscle protein except for phenylalanine. Diets containing six graded levels of L-phenylalanine (0.80, 1.10,1.40, 1.70, 2.00 and 2.30%) and a fixed level of tyrosine (0.52%) were formulated and fed to triplicate groups of C. mrigala juveniles twice a day at a rate of 10% of the fish body weight per day for 56 days. The optimum dietary requirement for phenylalanine, estimated by breakpoint regression analysis, was 1.75% of the diet (4.38% of the dietary protein) or 2.27% of the total aromatic amino acid (5.68% of the dietary protein). Beyond the optimum level, phenylalanine significantly depressed growth. The best feed efficiency, specific growth rate and survival were obtained with the diet containing close to the optimum level of aromatic amino acid.
  • Item
    Effects Of Fresh And Sea Water On Growth, Estradiol-17β Concentration And Ovarian Development In Juvenile Tilapia
    (Israeli Journal of Aquaculture - BAMIGDEH, 2004) Altun, Tülay ; Sarıhan, Ercan ; Kayrın, Levent ; Doran, Figen
    The effects of fresh water and sea water on growth, estradiol-17β levels, ovarian and oocyte development of Oreochromis niloticus, O. aureus and Tilapia zilli were determined. Sea water affected growth positively (p<0.05) but estradiol-17β concentrations in fish reared in sea water did not reach the levels in fish reared in fresh water. Ovarian stages developed differently in sea and fresh water. Ovulation occurred only when the fish were grown in fresh water whereas mature and atretic oocytes were seen simultaneously in all species when grown in sea water. There were no statistically significant differences in oocyte diameter between the groups grown in fresh and sea water (p>0.05).
  • Item
    Combined Effects Of Temperature And Salinity On Egg Hatching Rate And Incubation Time Of Penaeus Semisulcatus (Decapoda: Penaeidae)
    (Israeli Journal of Aquaculture - BAMIGDEH, 2004) Aktas, M. ; Eroldogan, O.T. ; Kumluo, M.
    This study was undertaken to determine the combined effects of temperature and salinity on the incubation time and hatching rate of Penaeus semisulcatus eggs in controlled laboratory conditions. Fertilized eggs, from a female caught in nature and spawned in our laboratory, were stocked in 2-l round bottom glass flasks and received one of nine temperature (24, 28 and 32°C) and salinity (30, 35 and 40 ppt) combinations. The eggs hatched in all treatments. The hatching rate increased as salinity increased and was highest at 24°C. In terms of hatching rate, the best combinations in descending order were 24°C at 40 ppt, 32°C at 40 ppt and 28°C at 40 ppt. However, the incubation time was longer at 24°C (17.5 h) than at 28°C (14.5 h) or 32°C (11.5 h).