Volume 54, Issues 1-4, 2002

Clinical And Pathological Investigation Of Psychrobacter Immobilis Infection In Rainbow Trour (Oncorhynchus Mykiss, Walbaum)

Hisar, Olcay; Yanik, Telat; Hisar, Sükriye Aras — Tue, 01 Jan 2002 00:00:00 GMT

The pathogenicity of Psychrobacter immobilis, isolated from naturally infected rainbow trout Oncorhynchus mykiss, was investigated. In experimentally-infected trout, no mortality was recorded during 35 days but the following external and internal symptoms were observed. Externally, skin was darkened, gills were pale and swimming was abnormal. Internally, there were dilatations of the vascular structures on cross-sections of the liver; vascular congestion, inflammatory mononuclear cell infiltration and degeneration in the gills; interstitial inflammatory mononuclear cell infiltration and free bleeding in patches of the posterior kidney; vascular con- gestion and free bleeding in the spleen; degeneration, atrophy, polymorphonuclear leukocyte infiltration and liquefaction necrosis in muscle fibers; edema, inflammatory mononuclear cell infil- tration and basophilic degeneration among muscle fibers of the heart; and congestion in vascu- lar structures on cross-sections of the brain tissue. It is suggested that P. immobilis is an oppor- tunist pathogen that causes secondary infections.

Production Of Androgenetic Nile Tilapia, Oreochromis Niloticus L.: Optimization Of Heat Shock Duration And Application Time To Induce Diploidy

Karayücel, Sedat; Karayücel, Ismihan; Penman, David; McAndrew, Brendan — Tue, 01 Jan 2002 00:00:00 GMT

Diploid androgenetic Nile tilapia, Oreochromis niloticus, were produced using 5 min UV irradia- tion at 150 μW/cm and heat shock at 42.5oC for 3:30 min applied 25 min after fertilization. The survival rates to morula, pigmentation, hatching and yolk sac resorption stages were 42.84±4.73%, 10.69±2.24%, 2.03±0.60% and 0.07±0.07% (relative to controls), respectively. A significant female, but not male, effect on the survival was confirmed. Multilocus DNA finger- printing produced by hypervariable 33.15 DNA probe verified the all-paternal inheritance in the androgens. The sex ratio of the androgenetic tilapia was not significantly different from the expected ratio of 1:0 (male:female), indicating that O. niloticus has a monofactorial sex-deter- mining mechanism with female homogamety and male heterogamety. This study confirmed that the YY genotype is viable and fertile in O. niloticus.

Spat Settlement And Growth On A Long-line Culture System Of The Mussel, Mytilus Galloprovincialis, In The Southern Black Sea

Tue, 01 Jan 2002 00:00:00 GMT

Spat settlement and growth at the depths of 3 and 7 m in a long-line mussel system in the south- ern Black Sea were determined in two seasons. The first spat collectors were hung in July 1997, the second in January 1998. Temperature, salinity, seston, particulate organic matter and chloro- phyll-a were measured monthly. Depth had no significant effect on any of these parameters (p>0.05). There was a significant positive correlation between particulate organic matter and chlorophyll-a (p<0.05) at both depths. On the first collectors, most of the spat settled from October to January and on the second most settled in April-May 1998. The mean shell length, height, width and weight of the mussels from the first collectors were 32.11±0.68, 18.32, 11.76±0.35 mm and 3.40±0.22 g, respectively. Spat collectors were most efficient in February and March when heavy spat settlement occurred and predation and fouling were minimal. Growth performance of seeds was high due to the favorable environment. Recommendations for spat collection and cultivation are given.

Growth And Survival Of Penaeus Merguiensis Postlarvae At Different Salinities

Zacharia, Sherly; Kakati, V.S. — Tue, 01 Jan 2002 00:00:00 GMT

The growth and survival of postlarval Penaeus merguiensis were examined to optimize condi- tions and improve farm production. Postlarvae were subjected to one of four salinities (5-35 ppt) for a period of 28 days. Results indicated maximum survival at 25 ppt while the best growth rate was obtained at 15 ppt. The highest performance index was obtained at 15 ppt. Hence, 15 ppt was found to be the optimum salinity for the production of P. merguiensis postlarvae. The fast growth rate and good tolerance of P. merguiensis larvae to a wide range of salinity in captivity indicate that P. merguiensis is a promising candidate for aquaculture.

Milt Production Of Sea Bass Lates Calcarifer Bloch Administered An Analogue Of Luteinizing Hormone-Releasing Hormone And 17α-Methyltestosterone

Hilomen-Garcia, G.V.; Baldevarona, R.B.; Lacanilao, F. — Tue, 01 Jan 2002 00:00:00 GMT

The milt production responses of sexually mature sea bass Lates calcarifer to (D-Ala6, Pro9-N- ethylamide) luteinizing hormone-releasing hormone (LHRHa) and 17α-methyltestosterone injec- tions were examined. At 24 h after injection of a low dose of LHRHa (20 μg/kg BW), the sperm count decreased significantly compared to saline-treated fish, but it returned to pre-treatment levels 48 h after injection, suggesting a possible hydration of the milt. Other milt parameters (milt volume, sper- matocrit, sperm production) in LHRHa-treated fish did not vary from their controls at 24 or 48 h after injection but the overall pattern suggested a reduction in milt viscosity. Total expressible milt and spermatozoa collected over the 48-h experiment was approximately three-fold higher in LHRHa-injected fish than in saline-injected fish, indicating a stimulation of spermatozoa produc- tion, not merely milt dilution due to hydration. In a second experiment, sperm count and spermatocrit were significantly lower than those of saline-injected fish at 17 and 48 h after a single injection of a high dose of LHRHa (80 μg/kg BW). A methyltestosterone injection combined with the LHRHa injection also resulted in a significant- ly lower sperm count, but the spermatocrit remained comparable to the control group, suggest- ing a suppression of the LHRHa-induced milt hydration response. Results demonstrate that LHRHa stimulates milt hydration and spermatozoa production in milting sea bass and that a simultaneous methyltestosterone injection partially suppresses this response.

Dietary Threonine Requirement Of Indian Major Carp, Cirrhinus Mrigala (Hamilton), Juveniles

Benakappa, S.; Varghese, T.J. — Tue, 01 Jan 2002 00:00:00 GMT

A growth study was conducted to determine the dietary threonine requirement of juveniles of the Indian major carp (Cirrhinus mrigala) known as “mrigal”. Diets containing casein and gelatin as sources of intact proteins were supplemented with crystalline amino acids to obtain a crude pro- tein content of 40%. Six diets with different levels of threonine (1.0, 1.3, 1.5, 1.7, 1.9 and 2.1%) were fed to triplicate groups of mrigal juveniles twice a day for 56 days. The dietary threonine requirement, estimated by break-point analysis, was 1.66% of the dry diet (4.15% of the dietary protein). The highest growth and specific growth rate were recorded in fish fed the diet contain- ing 1.7% threonine.

Alterations In The Hematological Parameters Of Rainbow Trout, Oncorhynchus Mykiss, Exposed To Cypermethrin

Atamanalp, Muhammed; Yanik, Telat; Haliloglu, H. Ïbrahim; Aras, M. Sıtkı — Tue, 01 Jan 2002 00:00:00 GMT

Rainbow trout were exposed to sublethal concentrations of the pesticide cypermethrin (1/8, 1/4 and 1/2 of the LC50, 0.0082 mg/l) for 21 days at 24-hour intervals. At the end of the exposure period, hematological parameters were investigated. As the concentration of cypermethrin increased, there were increases in red blood cells, hemoglobin concentration, mean corpuscu- lar hemoglobin, mean corpuscular hemoglobin concentration, thrombocyte count and erythro- cyte sedimentation rate. As the exposure increased, there were decreases in packed cell vol- ume, mean corpuscular volume and white blood cell count. Differences among treatments were significant (p<0.05) only for red blood cells, mean corpuscular volume, thrombocyte count and erythrocyte sedimentation rate when exposure rose from 1/8 to 1/2 of the LC50 concentration.

Effects Of Temperature On Survival And Growth Of Artemia From Tuz Lake, Turkey

Saygı, Yasemin Basbug; Demirkalp, F. Yıldız — Tue, 01 Jan 2002 00:00:00 GMT

The thermal constant, growth and survival of Artemia from Tuz Lake, Central Anatolia, were evaluated under laboratory conditions. Artemia nauplii (24-48 hours after hatching) were stocked into a 60 ppt salinity medium which contained Dunaliella and Oocystis. The Artemia were cul- tured at one of eight temperatures (2-degree intervals from 18° to 32°C) for 30 days, in two repli- cates. The animals grew faster but survival was lower as the temperature increased. Complete development from the nauplius stage to the adult stage required 30 days at 18°C, 20 days at 24°C and 15 days at 30°C. The thermal constant was 356±6 day-degrees and the developmen- tal zero value was 6.3±1.9°C.

Evaluation Of Plant Proteins As Partial Replacement For Animal Proteins In Diets For Penaeus Indicus And P. Merguiensis Juveniles

Peñaflorida, Veronica D. — Tue, 01 Jan 2002 00:00:00 GMT

The growth rate and survival of two white shrimps, Penaeus indicus and P. merguiensis, fed diets in which fishmeal was partially replaced with plant protein sources were investigated in three trials. In trial 1 with P. indicus, soybean, yeast and leaf meals of kangkong, papaya and Cassia tora L. were screened as partial substitutes for fishmeal. The total biomass of shrimp fed 20% yeast (20yeast) was highest but not significantly different than that of shrimp fed 10yeast and 10papaya. Survival was highest with 20yeast, 10papaya and 10yeast . Shrimp fed Cassia tora L. had the highest weight gain and SGR but their survival was similar to those fed poor performing diets. In trial 2 with P. merguiensis, the ingredients were modified by decreas- ing fishmeal and increasing the yeast and soybean substitution. The biomass of the shrimp fed 10yeast was similar to that of the shrimp fed 20yeast and 26soybean, the weight gain and SGR were similar to shrimp fed 20yeast while survival was highest but not different from 20yeast and 26soybean. In trial 3 with P. indicus, weight gain and SGR were best with 20yeast and 34soy- bean. However, biomass and survival did not differ among replacement levels. The performance of the white shrimp varied with different levels of yeast and soybean meal incorporation. The response of P. indicus was best with 20yeast (15% by weight) or 34soybean meal (34% by weight) while that of P. merguiensis was with 10yeast (7% by weight), 20yeast (15% by weight) or 26soybean meal (26% by weight). Partial replacement of fishmeal with yeast or soybean meal would result in lower feed costs but the use of these feeds needs further refine- ment since survival was low in all treatments. Rearing techniques, such as increasing the feed- ing frequency, simulating deep pond conditions or using adequate substrates, should be refined.

Effect of Diets With Protein From Different Sources On The Growth Of Goldfish, Carassius Auratus

Mohanta, K.N.; Subramanian, S. — Tue, 01 Jan 2002 00:00:00 GMT

Four isoproteinous (40% crude protein) feeds (based on chicken liver, lean shrimp meal, mus- sel meal or squid meal) were fed to goldfish, Carassius auratus, of 4.61±0.427 g for 30 days at 10% of their body weight. The effect of the feeds on growth performance were compared with two commercial feeds, Brine Shrimp Flake and Tubifex Worm (59% crude protein each). There were no significant differences in food conversion ratio or specific growth rate between the treat- ments. The protein efficiency ratios (PER) of all the formulated feeds were significantly better than that of the Brine Shrimp Flake and the PER of the diets based on mussel and squid meal were also significantly better than Tubifex Worm. The weight increment with Tubifex Worm was significantly highest of all the treatments. Considering the nutritional parameters and cost of pro- ducing one kilogram of fish, the diet based on lean shrimp meal was the best. The cost of pro- ducing one kilogram fish using the formulated feeds ranged Rs. 93.75-231.30. Using Brine Shrimp Flake and Tubifex Worm, the costs were Rs. 1150 and Rs. 3500 per kg, respectively. The cost of goldfish rearing can be appreciably reduced by using feeds prepared with locally available protein sources. The crude protein level of 40% was sufficient for the goldfish, as the PER of the fish fed the formulated feeds was better than that of the fish fed the commercial feeds.

Distribution Of Different Forms Of Copper In Freshwater Pond Soils Of Orissa, India

Adhikari, S. — Tue, 01 Jan 2002 00:00:00 GMT

The distribution of native copper fractions in freshwater pond soils of Orissa and their relation- ship to important soil properties were studied. Total Cu and diethylene triamine penta acetic acid (DTPA) extractable Cu ranged 7.0-24.0 and 2.0-4.9 mg/kg soil, respectively, with mean values of 12.7 and 3.1 mg/kg. The amounts of exchangeable, weakly adsorbed, moderately adsorbed, strongly adsorbed and organic matter associated Cu ranged 1.7-2.6%, 3.5-6.0%, 3.3-6.6%, 0.7-2.2% and 0.8-7.2% of the total Cu, respectively. Cu occluded or bound by car- bonates or other acid-soluble mineral fractions was 1.5-6.1% of the total Cu. Most of the Cu (58-91%) was in the residual fraction. All the chemical fractions of Cu significantly correlated with each other and with the organic carbon status of the soils.

Fertilization Of Freshwater Fish Ponds With Cobalt And Its Adsorption And Desorption In The Pond Sediment

Adhikari, S.; Ayyappan, S. — Tue, 01 Jan 2002 00:00:00 GMT

The use of cobalt as a micro-nutrient fertilizer in the culture of the freshwater Labeo rohita was evaluated in terms of primary productivity, Chlorophyll a production, plankton volume and fish growth. Three cobalt doses (5, 10 and 15 kg CoCl2/ha) were tested. In the 5 and 10 kg CoCl2/ha treatments, primary productivity, Chlorophyll a production, plankton volume and growth of Labeo rohita increased (p<0.05). The highest increment was obtained in the 10 kg CoCl2/ha treatment. The adsorption and desorption of the cobalt in the pond sediment fit the Langmuir isotherm. The highest adsorption and desorption values were found in pond sediments from the Dhenkanal area, due to its higher clay content, total Mn content and pH, indicating that sediments with a higher capacity to adsorb cobalt also have a higher capacity to desorb cobalt.

The Protein Sparing Effects Of High Lipid Levels In Diets For Rainbow Trout (Oncorhynchus Mykiss, W. 1792) With Special Reference To Reduction Of Total Nitrogen Excretion

Yigit, Murat; Yardim, Öztekin; Koshio, Shunsuke — Tue, 01 Jan 2002 00:00:00 GMT

This research sought to develop low-protein, high-energy (less-polluting) diets for rainbow trout to properly utilize protein and reduce total nitrogen excretion. Duplicate groups of rainbow trout were fed one of four experimental diets with a protein to energy (P:E) ratio of 25, 24, 22 or 19 mg/kJ and a lipid content of 12, 13, 17 or 26%, respectively. The diets were given to fish with a mean initial weight of 181 g for 70 days. At the conclusion of the trial, mean weights ranged from 353.17 g (94% weight gain) to 394.75 g (118% weight gain) with 100% survival in all treat- ments. Weight gain, feed efficiency and protein retention increased as the dietary lipid content increased and as the P:E ratio decreased. Fish fed the 22 mg protein/kJ energy diet (17% lipid, 44% protein, 20.34 kJ/g gross energy) performed best. This indicates that the protein content in practical trout feeds can be reduced from the currently used 47% to around 44% without reduc- ing the growth rate and feed efficiency, if high quality protein is used and the gross energy is increased by lipid to about 20.34 kJ/g diet. The low-protein, high-energy diets reduced the total nitrogen excretion from the rainbow trout by 27%.

Early Development And Growth Of Arctic Charr (Salvelinus Alpinus) And Rainbow Trout (Oncorhynchus Mykiss) At A Low Water Temperature

Yanik, Telat; Hisar, Sükriye Aras; Bölükbasi, Canan — Tue, 01 Jan 2002 00:00:00 GMT

Hatchery traits and growth of eggs and fry of rainbow trout, Oncorhynchus mykiss, and arctic charr, Salvelinus alpinus, were tested in fresh water of a low temperature. There were significant differences (p<0.05) between the survival rates from fertilization through the eyed stage and the first exogenous feeding. No significant differences were observed between species with regard to feed conversion or survival of fry at the end of the 154-day trial, but weight gain and specific growth rate differed significantly (p<0.05). These results suggest that the arctic charr could be considered an alternative to rainbow trout, particularly in coldwater farms.

Microflora On The Skin Of European Eel (Anguilla Anguilla L., 1758) Sampled From Creek Yuvarlakçay, Turkey

Ugur, Aysel; Yılmaz, Fevzi; Sahin, Nurettin — Tue, 01 Jan 2002 00:00:00 GMT

Bacterial skin microflora of eel obtained from Mugla (Turkey) province were studied. The aero- bic bacteria associated with skin and slime were estimated using the dilution plate technique. The dominant bacterial species were Pseudomonas spp. (17.23%), Acinetobacter baumannii (15.51%) and Stenotrophomonas maltophilia (12.05%). A lower frequency of Gram-positive bacteria (18.93%) was found in samples.

Influences Of Dietary Protein Deficiency On Amino Acid And Fatty Acid Composition In Tilapia, Oreochromis Niloticus, Fingerlings

Ogunji, Johnny O.; Wirth, Manfred — Tue, 01 Jan 2002 00:00:00 GMT

The influence of dietary protein deficiency on the amino acid and fatty acid compositions of tilapia (Oreochromis niloticus) fingerlings was studied. Two experimental diets (0.81% and 33.32% protein, dry matter) were prepared. The protein content of fish fed diet 1 (0.81% pro- tein) decreased from 57.14% to 49.18% in eight weeks. Fish fed diet 2 (33.32% protein) had higher protein and amino acid contents. The lipid content of fish fed diet 1 was higher than that of fish fed diet 2, suggesting that carbohydrates transformed into lipids. The levels of fatty acids 16:0 and 18:2 n-6 in fish fed diet 1 remained nearly unchanged and did not reflect the diet, demonstrating that fatty acids in diet 1 may not have been incorporated into the triglycerides of the tissues. Possible impairment of lipid secretion from the liver, caused by depletion of protein in the blood lipoprotein, may have affected the transport of lipids to the muscles. A dietary pro- tein deficiency results not only in a deficiency of essential amino acids in the body but also affects transport and storage of lipids within the fish.

Epitopes Of Tilapia Red Blood Cells. I. Species-Specific Antibodies For The Control Of Tilapia Breeding Stocks

Timan, Bracha; Shirak, Andrey; Segal, Ruth; Machnes, Ziv; Avtalion, Ramy R. — Tue, 01 Jan 2002 00:00:00 GMT

Specific antisera against red blood cells of some tilapia species were obtained by reciprocal inter- specific and intergeneric immunizations. The antisera were used to confirm co-dominant expres- sion of epitopes in F1 interspecific hybrids and to identify the parental origin of three red tilapia strains. The antisera in all hybrids (Oreochromis niloticus x O. mossambicus, O. aureus x O. horno- rum, O. niloticus x S. galilaeus and O. niloticus x O. aureus) were positive to both parental strains. However, while all F1 hybrids of O. mossambicus x O. hornorum were positive to anti-O. mossambi- cus antiserum, only 50% were positive to anti-O. hornorum antiserum. In most cases, these results point to co-dominant expression of the species-specific epitopes in hybrids. In addition, the triple parental origins of the Philippine red tilapia (positive for O. aureus, O. mossambicus and O. niloticus epitopes) and of mossambicus red tilapia (positive for O. hornorum, O. mossambicus and O. niloticus epitopes) were assessed. The O. niloticus red tilapia, described as a purebred red variant of O. niloticus, was positive for both anti-O. niloticus and anti-O. aureus antibodies, with a significantly more intense reaction to the latter. A possible genetic basis of this last finding is discussed.

Use of Melanophore Patterns On The Ventral Side Of The Head To Identify Fry Of Grey Mullet (Teleostei: Mugilidae)

Minos, G.; Katselis, G.; Ondrias, I.; Harrison, I.J. — Tue, 01 Jan 2002 00:00:00 GMT

Examination of fry of five species of grey mullet revealed that the shape of the lower jaw and the melanophore patterns along the edge of the lower jaw and the ventral side of the head are species-specific. Mugil cephalus is characterized by an acute angle of the dentary symphysis and lightly pigmented ventro-opercular and gular regions of the head. In Liza aurata, the mandibular region has spots of pigment at the corners of the mouth, the gular region is lightly pigmented with a single row of melanophores, the ventro-opercular region of the head has two rows that form a distinct arch and, in specimens over 20 mm TL, at least one of these rows extends to the posterior ventro-opercular region. In Liza ramada, the pigmentation is darkest in the mandibular and gular regions of the head, the melanophores in the mandibular region in specimens of 30-40 mm TL are concentrated around the anterior tip of the jaw and the corners of the mouth, and the anterior ventro-opercular region usually has a single row of melanophores that may extend into the posterior ventro-opercular region. In Chelon labrosus, there are two rows of melanophores in the ventro-opercular region and one or two rows in the gular region which usually extend beyond the eye into the posterior sector. In Liza saliens, there are two rows of melanophores in the ventro-opercular region and two in the gular region which rarely extend beyond the eye to the posterior sector. These observations were used to create a key which may be useful for identifying fry of grey mullet species grown in aquaculture in the Mediterranean region.

Aquaculture In Turkey

Memis, Devrim; Demir, Nilsun; Eroldogan, Orhan Tufan; Kucuk, Semra — Tue, 01 Jan 2002 00:00:00 GMT

Marine and freshwater aquaculture in Turkey have grown substantially. The first trout farm was established in the 1960s and the first marine cage farm for sea bream and sea bass in 1985. From the beginning of the 1970s to 1999 the number of licensed fish farms increased from two to 1,444. Since 1995, the number of cage farms has grown to 57 and production reached 4,100 tons in 1999. Total aquaculture production grew from 3,075 tons in 1986 to 63,000 tons in 1999. Production is dominated by inland production, mainly of trout (Oncorhynchus mykiss), which supplies 60% of the total. From 1995 to 1999, marine production increased from 8,494 tons to 25,230 tons. The major contributors are sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax). Because of the rel- atively high temperatures in the Black Sea, Atlantic salmon (Salmo salar), cultured from the late 1980s to 1997, is no longer grown; only rainbow trout (O. mykiss) in floating net cages is produced. Because of the growing demand caused by increased population and export, aquaculture pro- duction and consumption in Turkey are expected to grow. New fish and shellfish species, mainly marine, are being developed. The bureaucracy involved in licensing fish farms, especially in marine environments, is complicated, time-consuming, and suffers from a lack of technical knowl- edge and insufficient exchange of know-how and cooperation concerning new developments. * Corresponding author. Present address: Istanbul Universitesi, Su Ürünleri Fakültesi, 34470 Laleli, Istanbul, Turkey; e-mail: mdevrim@istanbul.edu.tr

In Memoriam Professor Boaz Moav (1938-2002)

Mires, Dan — Tue, 01 Jan 2002 00:00:00 GMT

On January 28, 2002, Professor Boaz Moav passed away after a long and valiant struggle with his ailment. We have lost both a good friend and a dedicated scientist who contributed greatly to the scientific aspects of fish culture.