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HUSBANDRY STRESS DURING EARLY LIFE STAGES AFFECTS THE STRESS RESPONSE AND HEALTH STATUS OF JUVENILE SEA BASS, DICENTRARCHUS LABRAX
S. Varsamos, G. Flik, J.F. Pepin, S.E. Wendelaar Bong, G. Breuil-2005
Fish & Shellfish Immunology 20 (1): 83-96
Abstract:
In aquaculture management it is important to establish objective criteria to assess health and welfare of the fish. Here we show that European sea bass (Dicentrarchus labrax) confronted with husbandry-associated stress (tank cleaning, i.e. scrubbing, and water temperature variation) during early life stages show poorer survival and disease resistance as juveniles. We evaluated several parameters for stress (plasma cortisol, glucose and lactate, hydromineral status), growth performance, the immune response (plasma IgM levels) and the effects of a nodavirus challenge. Principal component analysis allowed the establishment of a stress panel including plasma cortisol, osmolality, IgM levels and weight. Sea bass juveniles reared during early life in high and constant temperature perform best in terms of stress-related parameters assessed by principle component analysis. Variable water temperature triggers dramatic changes in plasma cortisol, osmolality, IgM levels, body weight and susceptibility to nodavirus that suggest a strong and prolonged activation of the HPI axis. Scrubbing induces some disturbances typical for mild short-term, acute stress, viz. increased plasma osmolality and decreased IgM levels, but does not affect plasma cortisol, growth or susceptibility to nodavirus of sea bass. Our data fit well with the concept of allostasis. We discuss the relevance of our work for sea bass aquaculture.
(IFREMER, Laboratoire de Recherche Piscicole de Méditerranée, DRV/RA, Chemin de Maguelone, 34250 Palavas-les-Flots, France; email of Gilles Breuil: gilles.breuil@ifremer.fr)

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ACCUMULATION OF EICOSAPENTAENOIC ACID IN NANNOCHLOROPSIS SP. IN RESPONSE TO ELEVATED CO2 CONCENTRATIONS
Hisashi Hoshida, Takayuki Ohira, Akira Minematsu, Rinji Akada, Yoshinori Nishizawa-2005
Journal of Applied Phycology 17 (1): 29 – 34
Abstract:
To increase eicosapentaenoic acid (EPA, 20:5, n-3) content in the marine alga Nannochloropsis sp., the effect of CO2 concentration during cultivation has been investigated. In a batch culture under normal atmospheric conditions (0.037% CO2), the EPA content per cell increased during the first 1.5 days and then decreased immediately even though the cells were in an exponential growth phase. Increasing the CO2 concentration to 0.3% and 2% over day 1.5 retained the EPA content at the higher concentration for another 1 and 2 days, respectively, suggesting that the EPA accumulation is enhanced by elevated concentrations of CO2. EPA accumulation in response to elevated CO2 concentrations was also observed during a later growth phase when CO2 was introduced after the decrease of EPA content. The addition of CO2 caused a slight decrease in the pH of the medium though this was not the cause of the observed EPA accumulation as addition of acidic buffer did not affect the EPA content. The maximum EPA production was obtained when 2% CO2 was supplied 12 h prior to the end of the exponential growth. The total EPA production during 4-day cultivation was about twice that obtained with ambient air. These results suggest that the available CO2 concentration affects the EPA content in Nannochloropsis sp.
(Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering, Yamaguchi University, 2-16-1 Tokiwad, Ube 755-8611, Japan; email of Hisashi Hoshida: hoshida@yamaguchi-u.ac.jp)

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ABUNDANCE AND GROWTH RESPONSE OF MICROALGAE AT MEGALON EMBOLON SOLAR SALTWORKS IN NORTHERN GREECE: AN AQUACULTURE PROSPECT
Nicolas P. Dolapsakis, Triantafyllos Tafas, Theodore J. Abatzopoulos, Stephanie Ziller, Athena Economou-Amilli-2005
Journal of Applied Phycology 17 (1): 39 – 49
Abstract:
There is continuous interest in many countries in maintaining and manipulating the rich ecological value of hypersaline ecosystems for aquaculture. The Megalon Embolon solar saltworks (northern Greece) were studied in sites of increasing salinity of 60–144 ppt to evaluate Dunaliella salina abundance and microalgal composition, in relation to physical and chemical parameters. Cluster and ordination analyses were performed based on the biotic and abiotic data matrices. Using fresh aliquots from 60 and 140 ppt salinity waters, phytoplankton performance was appraised with flask cultures in the laboratory by varying the inorganic PO4-P concentration at 23 °C and 30 °C. At the saltworks, among the most abundant microalgae identified were species of the genera Dunaliella, Chlamydomonas, Amphora, Navicula, and Nitzschia. Dunaliella salina populations were predominant comprising 5–22% of the total microalgal assemblages during spring, but only 0.3–1.0% during the summer, when grazing by Artemia parthenogenetica and Fabrea salina was intense. D. salina cell density in April–July was in the range of 0.4–12.5 × 106 L-1 with typical densities of 1.5–4.5 × 106 L-1. Overall, microalgal densities were high in salinities of =100 ppt when inorganic-P concentrations were =0.20 mg L-1 within saltworks waters. Multivariate analysis of species abundance showed that algal growth responses were primarily related to variation in salinity and inorganic-P concentrations, but also to NO3-N concentration. In the laboratory, experiments indicated effective fertilization and denser microalgal growth under high inorganic PO4-P applications (4.0 and 8.0 mg L-1) at 60 ppt salinity and 23 °C. The lower PO4-P applications (0.6–2.0 mg L-1) were more effective at 60 ppt salinity and 30 °C. At 140 ppt salinity, microalgal growth response was less obvious at any of the corresponding phosphorus concentrations or temperatures. In both salinity experiments, Dunaliella salina bloomed easily and was predominant among the microalgae. Our observations indicate that Dunaliella salina populations and the overall rich microalgal profile of the saltworks, along with their performance in laboratory mono–and mixed cultures hold promise for mass cultivation within the M. Embolon saltworks basins.
(Faculty of Biology, Department of Ecology and Systematics, University of Athens, Panepistimiopolis, Athens, Greece; email of Nicolas P. Dolapsakis: ndol@biol.uoa.gr)

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THE RELATIONSHIP BETWEEN EGG SIZE AND THE DURATION OF THE FACULTATIVE FEEDING PERIOD IN MARINE INVERTEBRATE LARVAE
Benjamin G. Miner, Lari A. McEdward, Larry R. McEdward-2005
Journal of Experimental Marine Biology and Ecology 321 (2): 135-144
Abstract:
Feeding larvae of marine invertebrates fuel development from both endogenous egg energy and exogenous energy obtained from the planktonic environment. Although both sources of energy likely influence certain larval stages, only the effects of exogenous food have been well studied. Despite the lack of research on the effects of egg size on larval stages, investigators have hypothesized that egg size influences the duration of the facultative feeding stage—the stage in which larvae can feed but do not have to because development is still being fueled by egg energy. To test this hypothesis, we investigated six species of sand dollars with different sized eggs and quantified the duration of the larval facultative feeding period of each species by comparing when fed and starved larvae diverged in size. Regardless of whether phylogeny was taken into account, the duration of the facultative feeding period was positively correlated with egg size. We further determined that our conclusions were not sensitive to either our estimation of the duration of the facultative feeding period, or the branch lengths of the phylogeny we used. This relationship is likely a result of larger eggs being provisioned with more energy, and may affect how well larvae can cope with natural variability in food concentrations. Furthermore, our results support an assumption of a theoretical model developed to understand the evolution of different life-history strategies in marine invertebrate larvae, which suggests that this relationship has important evolutionary consequences.
(Department of Zoology, University of Florida, Gainesville, FL 32611-8525, United States; email of B. Miner: bgminer@ucdavis.edu)

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METABOLIC RESPONSE OF JUVENILE GRAY SNAPPER (LUTJANUS GRISEUS) TO TEMPERATURE AND SALINITY: PHYSIOLOGICAL COST OF DIFFERENT ENVIRONMENTS
Mark J. Wuensche, Amelia R. Jugovich, Jonathan A. Hare-2005
Journal of Experimental Marine Biology and Ecology 321 (2): 145-154
Abstract:
Juvenile gray snapper (Lutjanus griseus) occupy a wide range of estuarine and nearshore habitats that differ in physico-chemical properties. To quantify the energetic cost of inhabiting these different habitats, routine metabolism of individual gray snapper was measured in the laboratory at 20 combinations of temperature (18, 23, 28, and 33 °C) and salinity (5, 15, 25, 35, and 45 psu). An open, flow-through respirometer was used, enabling trials to be run for long periods (16 h), while maintaining water quality (dissolved O2>70% saturation), and providing fish sufficient time to habituate to the chambers undisturbed. Video recordings of fish in the respirometer chambers were analyzed to quantify the spontaneous activity rate of individuals. Analysis of covariance, using fish weight and mean activity rate as covariates, indicated significant temperature and salinity effects on oxygen consumption. Oxygen consumption was significantly higher at high salinities, and the salinity effect was temperature dependent. A polynomial equation describing oxygen consumption as a function of temperature and salinity indicated the increase due to salinity from 5 to 45 psu at high temperatures (30–33 °C) was equivalent to a 3 °C increase in temperature. At intermediate temperatures (24–26 °C), the increase due to salinity from 5 to 45 psu was less dramatic, equivalent to a 2 °C increase in temperature. At the lowest temperatures (18 °C), salinity did not have a significant effect on oxygen consumption. The increased metabolic costs in high salinities (7% at the high temperature) represent a significant energy cost for juveniles, that would need to be balanced by lower predation risk or greater food availability to result in similar juvenile production compared to lower salinity environments.
(NOAA, NOS, Center for Coastal Fisheries and Habitat Research, 101 Pivers Island Road, Beaufort, NC 28516, USA; email of Mark.Wuenschel: Mark.Wuenschel@noaa.gov)

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INTRACYTOPLASMIC SPERM INJECTION USING CRYOPRESERVED, FIXED, AND FREEZE-DRIED SPERM IN EGGS OF NILE TILAPIA
Germán A. Poleo, Robert R. Godke, Terrence R. Tiersch-2005
Marine Biotechnology 7 (2): 104 – 111
Abstract:
Gamete preservation techniques are essential in animal husbandry as well as in assisted reproduction for humans. In this research we attempted to use 3 different sperm preservation techniques in combination with newly developed techniques for intracytoplasmic sperm injection (ICSI) to fertilize eggs of a teleost fish, the Nile tilapia (Oreochromis niloticus). Of 47 eggs injected with fresh sperm, 11 (23%) were fertilized, 5 developed abnormally, and 4 developed normally and hatched; from these, one grew to adulthood. Nuclear DNA content of 4 of the abnormal embryos indicated that they were diploid. Flow cytometric analysis of a blood sample from the surviving ICSI fish collected 2 months after fertilization indicated that the fish was diploid. Of 45 eggs injected with cryopreserved sperm, 9 (20%) developed to the blastula stage. Of 40 eggs injected with sperm preserved in 70% methanol, none were fertilized. No injections were possible with freeze-dried Nile tilapia sperm owing to technical difficulties during manipulation. Although the findings described here are limited, they provide the first steps toward using sperm preservation methods in addition to cryopreservation for fertilization in fishes.
(Aquaculture Research Station, Louisiana Agricultural Experimental Station, Louisiana State University Agricultural Center, 2410 Ben Hur Road, Baton Rouge, LA, 70803, U.S.A; email of Terrence R. Tiersch: ttiersch@agctr.lsu.edu)

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EFFECT OF TEMPERATURE ON SURVIVAL AND DEVELOPMENTAL PERIOD OF LARVAL SNOW CRAB CHIONOECETES OPILIO (BRACHYURA: MAJIDAE) REARED IN THE LABORATORY
Takayuki Kogane, Katsuyuki Hamasaki, Kinya Nogami-2005
Nippon Suisan Gakkaishi 71 (2): 161-164
Abstract:
To identify the optimal rearing temperature for the larval snow crab Chionoecetes opilio, newly hatched larvae were reared in 1-L beakers the temperature of which was regulated at 10, 12, 14, and 16°C, respectively. Survival rates to reach the second zoeal stage were ca. 90% at each test temperature; however, mass mortality occurred in the beakers of 16°C after the second zoeal stage. The highest survival rate to reach the first crab stage was obtained in the beakers of 14°C. Developmental period (days) to reach each larval stage decreased with increasing temperature. The coefficient of variation of the days required to reach each larval stage tended to be minimized in the beakers of 14°C. Consequently, we conclude that the optimal rearing temperature for the larval snow crab is ca. 14°C.
(Obama Station, National Center for Stock Enhancement, Fisheries Research Agency, Obama, Fukui 917-0117, Japan)

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INFLUENCE OF TIMING OF BRAZILIAN ARTEMIA NAUPLII FEEDING ON OCCURRENCE OF PSEUDOALBINISM IN TWO PLEURONECTID SPECIES
Masato Aritaki, Tadahisa Seikai-2005
Nippon Suisan Gakkaishi 71 (2): 165-171
Abstract:
In this study, the influence of Brazilian Artemia nauplii (BA) feeding on the occurrence of pseudoalbinism in two pleuronectid species (spotted halibut Verasper variegatus and brown sole Pseudopleuronectes herzensteini) was examined. BA were fed at six different periods from early larval stage (the stage at which they start to eat Artemia) to juvenile stage. Pseudoalbinism occurred at about 90-100% in the two pleuronectid species when BA was given before the flexion stage (E stage, spotted halibut; 10 mm TL, brown sole; 8 mm TL) suggesting that expression (or non-expression) of pseudoalbinism had been determined before the postflexion stage (F stage). For the prevention of pseudoalbinism, which possibly results in other deformities in relation to asymmetrical morphology, the stages before postflexion must be critically important in pleuronectid species.
(Miyako Station, National Center for Stock Enhancement, Fisheries Research Agency, Miyako, Iwate 027-0097, 2Department of Marine Bioscience, Faculty of Biotechnology, Fukui Prefectural University, Obama, Fukui 971-0003, Japan)

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DISINFECTION OF PARTHENOGENETIC EGGS OF THE ROTIFER BRACHIONUS PLICATILIS
Ken-Ichi Watanabe, Daisuke Shinozaki, Masahiko Koiso, Hiroshi Kuwada, Mamoru Yoshimizu-2005
Nippon Suisan Gakkaishi 71 (3): 294-298
Abstract:
The disinfectant effect of chemical and physical treatments on parthenogenetic eggs of the rotifer was investigated. No disinfectant effect was observed by treatment with ozonated or electrolyzed seawater, and triton-X under several conditions. Treatments with povidone-iodine at 50 mg/L as iodine, pH 2, and 10,000 mg/L of hydrogen peroxide were effective for disinfection, but hatching rate was low. Glutaraldehyde treatment at the concentration of 1,250 mg/L for 30 min effectively disinfected the eggs of rotifer and did not reduce the hatching rate of parthenogenetic eggs.
Notojima Station, National Center for Stock Enhancement, Fisheries Research Agency, Notojima, Ishikawa 926-0216, Japan)

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OTOLITH MARKING FOR EGGS, LARVAE AND JUVENILES OF OCELLATE PUFFER TAKIFUGU RUBRIPES BY ALIZARIN COMPLEXONE AND TETRACYCLINE
Yasuharu Matsumura-2005
Nippon Suisan Gakkaishi 71 (3): 307-317
Abstract:
Effective conditions for alizarin complexone (ALC) and tetracycline (TC) staining for the otoliths were examined in ocellate puffer eggs, larvae and juveniles to establish optimal methods by immersing in ALC or TC solution or by TC oral administration. To determine the optimum ALC or TC immersion conditions, eggs, larvae and juveniles were immersed in various combinations of ALC (5-100 mg/L) and TC (50-1000 mg/L) concentrations and treatment durations (6-24 h). To determine the optimum conditions for oral administration, juveniles were reared using artificial diets with various concentrations of TC (2.5-50 mg/g) and treatment periods (1-9 days). For both methods, optimum conditions were judged by the presence of fluorescent marks on otoliths under B-excited UV light and high survival rates (>90%) during the treatment. As a result, 9-19 combinations of concentration and duration of ALC and 2-11 combinations (TC) were found to be effective for immersion, and 5-11 combinations for oral administration depending on the fish stage. Fluorescent marks of ALC and TC were detected after more than 5 years and the treatments had no effect on the post-treatment survival and growth. These results suggest that these methods can be applied to surveys of stocking effectiveness by mark-recapture studies.
(Nagasaki Prefectural Institute of Fisheries, Nagasaki 851-2213, Japan)

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FATTY ACID COMPOSITION OF THE L-TYPE ROTIFER BRACHIONUS PLICATILIS PRODUCED BY A CONTINUOUS CULTURE SYSTEM UNDER THE PROVISION OF HIGH DENSITY NANNOCHLOROPSIS
Takayuki Kobayashi, Toshiya Nagase, Norihide Kurano, Akinori Hino-2005
Nippon Suisan Gakkaishi 71 (3): 328-334
Abstract:
Fatty acid profiles of the L-type rotifer Brachionus plicatilis harvested from a continuous culture system were compared respecting the quality of food algae. Nannochloropsis oculata propagated in high density by a panel type photo-bioreactor and fresh water Chlorella suspension on the market were tested. Continuous rotifer culture was carried out under 24°C and 26 psu in a 2000-mL polyethylene bottle.

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EFFECT OF ROTIFERS ENRICHED WITH TAURINE ON GROWTH IN LARVAE OF JAPANESE FLOUNDER PARALICHTHYS OLIVACEUS
Jau-Neng Chen, Toshio Takeuchi, Takayuki Takahashi, Tsutomu Tomoda, Masahiko Koiso, Hiroshi Kuwada-2005
Nippon Suisan Gakkaishi 71 (3): 342-347
Abstract:
This study was conducted to investigate the effect of rotifers enriched with taurine on the growth performance of larval Japanese flounder Paralichthys olivaceus. Rotifers enriched with 400 and 800 (mg/L) taurine or without taurine and thus having different levels of taurine were given to larvae for 16 days. The taurine content in rotifers significantly increased with the increase of time of enrichment and different taurine levels. Similarly, the taurine content in larvae at 16 dph fed rotifers enriched with taurine (205.2 and 453.5 mg/100g) was significantly higher than that in fish fed rotifers not enriched with taurine (53.3 mg/100 g). Larval growth was significantly improved by the feeding of rotifers enriched with taurine. In addition, morphological development of the larvae was superior to that of fish fed rotifers not enriched with taurine. These results suggest that the taurine content in rotifer affects both the growth and development of Japanese flounder larvae, and the taurine enrichment of rotifer is effective at the level of 400 mg/L (165.0-303.5 mg/100 g dry weight in rotifer).
(Faculty of Marine Science, Tokyo University of Marine Science and Technology, Minato, Tokyo 108-8477, Japan)

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RELATION OF SIZE AT RELEASE OF HATCHERY-REARED BLACK ROCKFISH SEBASTES INERMIS TO SURVIVAL IN A ZOSTERA BELT AROUND IKUNO ISLAND, HIROSHIMA PREFECTURE, JAPAN
Tomoya Murakami, Kouji Yoshioka, Satoshi Aida, Tetsuya Umino, Heisuke Nakagawa-2005
Nippon Suisan Gakkaishi 71 (3), 354-362 (2005)
Abstract:
To enhance the stock of black rockfish, Sebastes inermis, 2 cm-, 3 cm- and 5 cm-size groups of hatchery-reared fish were released in a Zostera belt around Ikuno Island after marking with ALC and fin cut. The larger the size, the farther from the release point they were recaptured and the better the survival rate. Especially, most of the 2 cm-size fish had disappeared about one month later. A predation test in a terrestrial tank confirmed that the redfin velvetfish Hypodytes rubripinnis was a dominant species as a predator at the release point, and significantly preyed on the 2 cm-size group more than the 3 cm-size group. According to changes of triglycerides in the muscle of 2 cm- and 5 cm-size groups after release, it took about one month for released fish to acclimate to the natural conditions. These results indicate that the fish size needs to be larger than 3 cm for the stock enhancement of this species in this area.
(Hiroshima Prefectural Fisheries Experimental Station, Aki, Hiroshima 737-1207, Japan)

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EFFECTS OF DIETARY FISH OIL,SOY-ACID OIL, AND YELLOW GREASE ON GROWTH AND HEPATIC LIPIDOSIS OF HYBRID TILAPIA FRY
Ercument Genc,, Erdal Yilmaz, Ihsan Akyurt -2005
The Israeli Journal of Aquaculture – Bamidgeh 57(2): 90-96
Abstract:
The objective of this study was to compare the effects of dietary lipids on growth and liver histopathology of hybrid tilapia, Oreochromis niloticus x O. aureus , fry (6.0 g). Fish were fed one of six diets containing 8.4% fish oil (control), 8.4% soy-acid oil, 8.4% yellow grease, 5.6% yellow grease plus 2.8% soy-acid oil, 2.8% yellow grease plus 4.6% soy-acid oil, or 4.2% soy-acid oil plus 4.2% yellow grease for 60 days. Growth was similar in all groups and retarded in comparison to earlier studies. Lipid accumulation as well as microvesicular (foamy degeneration) and macrovesicular degeneration in the liver were histopathologically detected.
(Programme of Fish Diseases, Faculty of Fisheries and Aquaculture, Tayfur Sokmen Campus, Mustafa Kemal University, 31040, Antakya, Hatay, Turkey; email of E. Genc: egenc@mku.edu.tr or ercumentgenc@yahoo.com)

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EFFECT OF TEMPERATURE ON EMBRYONIC DEVELOPMENT IN SHARPSNOUT SEABREAM (DIPLODUS PUNTAZZO) EGGS
Kursat Firat, Sahin Saka, Osman Ozden-2005
The Israeli Journal of Aquaculture – Bamidgeh 57(2): 105-114
Abstract:
Embryonic development of sharpsnout seabream (Diplodus puntazzo) was studied at eleven water temperatures (two degree intervals from 12 to 32°C). Embryos successfully developed at temperatures of 16-28°C. Cells did not divide at the temperature extremes of 12 and 32°C. Total mortality was observed by the 128 cleavage stage at 14°C and all eggs were dead by the time the embryos extended 2/3 of the internal circumference of the egg at 30°C. There was an inverse relationship between incubation temperature and the rate of embryonic development.
( Department of Aquaculture, Faculty of Fisheries, Ege University, 351000 Bornova, Izmir, Turkey; email of K. Firat: kfirat@sufak.ege.edu.tr)

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MANAGEMENT INDUCED CHANGES IN FOOD SELECTION, GROWTH AND SURVIVAL OF KOI CARP, CYPRINUS CARPIO VAR. KOI L., IN TROPICAL PONDS
Prithwiraj Jha, Sudip Barat -2005
The Israeli Journal of Aquaculture – Bamidgeh 57(2): 115-124
Abstract:
The effects of different management regimes on the feeding habits and food selection of koi carp (Cyprinus carpio var. koi L.) larvae were examined. Weight gain, fish deformities, and survival were compared in an 11-week growth trial conducted in tropical ponds maintained according to four culture regimes: (1) live food system; (2) poultry manure treated system; (3) cow dung treated system; and (4) a control. The Ivlev’s Electivity Index showed that koi larvae avoided phytoplankton and preferred cladocerans, an important source of natural food in all the regimes. In the poultry and cow manured ponds, the larvae were negatively elective towards copepods although they were more abundant than cladocerans. Weight gain and survival was significantly higher in the live-feed system (p<0.05) than in the other systems. Fish deformities were significantly higher (p<0.05) in the control.
(Aquaculture and Limnology Laboratory, Department of Zoology, University of North Bengal, District Darjeeling, West Bengal 734 430, India; email of S. Barat: sudipbarat@rediffmail.com)

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EFFECT OF FREEZING TECHNIQUES, EXTENDERS AND CRYOPROTECTANTS ON THE FERTILIZATION RATE OF FROZEN RAINBOW TROUT (ONCORHYNCHUS MYKISS) SPERM
Yusuf Bozkurt, Ergun Akcay, Necmettin Tekin, Selcuk Secer-2005
The Israeli Journal of Aquaculture – Bamidgeh 57(2): 125-130
Abstract:
Rainbow trout (Oncorhynchus mykiss)sperm was frozen in liquid nitrogen in straws or as pellets on dry ice and stored in liquid nitrogen until artificial insemination. Sperm was diluted with one of three extenders containing 15% DMSO or 15% DMA as a cryoprotectant at a ratio of one part sperm to two parts extender. The straws were thawed in a water bath while the frozen pellets were thawed in their own extenders at 30oC for 30 s. For both freezing methods, the best fertilization results were obtained with extender III containing 15% DMSO, 52.3% (56.3% of the control) for sperm frozen in straws and 48.4% (52.4% of the control) for sperm frozen as pellets. The interaction between extender and cryoprotectant was statistically significant ( p<0.05).
(Department of Aquaculture, Faculty of Fisheries, Mustafa Kemal University, 31040 Hatay, Turkey; emaili of Y. Bozkurt: yfbozkurt@mku.edu.tr)

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EMBRYONIC AND LARVAL DEVELOPMENT OF STRIPED SEA BREAM (LITHOGNATHUS MORMYRUS L 1758)
Kursat Firat, Sahin Saka, H. Okan Kamaci-2005
The Israeli Journal of Aquaculture – Bamidgeh 57(2): 131-140
Abstract:
Development of the embryonic and yolk-sac larvae of striped sea bream (Lithognathus mormyrus) was investigated. The average egg and oil globule diameters were 0.71±0.1286 mm and 0.18±0.1344 mm, respectively. The morula, gastrula, and neurula stages, somite formation, and hatching occurred 2:10, 5:15, 8:45, 9:45, and 21:15 hours after fertilization. The total length, yolksac volume, oil globule volume, digestive tube length, otolith diameter, head length, eye diameter, preanal and postanal lengths of newly hatched larvae were 1.74±0.03 mm, 0.12±0.008 mm3, 0.003±0.0002 mm3, 0.47±0.02 mm, 54±8 µm, 299±11 µm, 157±8 µm, 911±0.3 µm, and 827±0.03 µm. When the mouth opened 40 h after hatching, these measurements were 2.87±0.014 mm, 0.003±0.001 mm3, 0.001±0.0001 mm3, 0.61±0.015 mm, 134±8 µm, 376±10 µm, 221±13 µm, 1.02±0.03 mm, and 1.84±0.03 mm. During the first 18 hours, the larvae reached 84% of its final total length, the yolk sac was 65% absorbed, and the oil globule was 62% absorbed. Statistical analysis showed negative allometry for the relationships between total length and yolk-sac volume (r2 = 0.88) and total length and oil globule volume (r2 = 0.76), and positive allometry for the relationship between total length and digestive tube length (r2 = 0.89).
(Aquaculture Department, Faculty of Fisheries, Ege University, 35440 Urla-Iskele, Izmir, Turkey; email of K. Firat: kfirat@sufak.ege.edu.tr )

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A PRELIMINARY STUDY ON THE EFFECTS OF DIFFERENT LIGHT INTENSITIES ON HATCHING OF EUROPEAN SQUID (LOLIGO VULGARIS LAMARCK, 1798) EGGS
Halil Sen-2004
Turkish Journal of Fisheries and Aquatic Sciences 4 (1): 1-4
Abstract:
In this study, effects of different light intensities on development and hatching success of European squid (Loligo vulgaris Lamarck, 1798) eggs were investigated. In the experiments, L. vulgaris’s eggs were separately incubated at 600 lux, 140 lux, 33 lux, 9.5 lux, and 2.5 lux light intensity levels for 24 h. During the experiments, sea water temperature and salinity were measured as 14.3±1.8°C and 37±0.5 ppt. The hatching occurred between 36 and 49 days at 600 lux, 39 and 54 days at 140 lux, 39 and 53 days at 33 lux, 43 and 61 days at 9.5 lux, and 40 and 55 days at 2.5 lux light intensity levels. The maximum hatching rates and hatching success of the eggs were determined as 99.7% at 33 lux and 95.2% at 9.5 lux, respectively.
(Ege University, Faculty of Fisheries, Department of Aquaculture, 35440, Iskele-Urla, Izmir, Turkey; email of Halil Sen: halilsen35@hotmail.com)

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EFFECT OF DIFFERENT APPLICATION RATES OF COWDUNG AND POULTRY EXCRETA ON WATER QUALITY AND GROWTH OF ORNAMENTAL CARP, CYPRINUS CARPIO VR. KOI, IN CONCRETE TANKS
Prithwiraj Jha, Kripan Sarkar , Sudip Barat-2004
Turkish Journal of Fisheries and Aquatic Sciences 4(1): 17-22
Abstract:
Larvae (0.09±0.025 g) of Koi carp (Cyprinus carpio vr. koi) were cultured in outdoor concrete tanks for 90 days. Individual weight gain and survival rates were compared among a control (C), three treatments manured every 10 days with cowdung, applied at 0.13 kg/m3 (C1), 0.26 kg/m3 (C2), and 0.39 kg/m3 (C3), and three treatments manured every 10 days with poultry excreta, applied at 0.13 kg/m3 (P1), 0.26 kg/m3 (P2), and 0.39 kg/m3 (P3). Weight gain of Koi carp stocked at P2 was significantly higher than other treatments. There was a significant difference in survival of Koi carp among the treatments, ranging from 65.5% to 86% in C and P2, respectively. The C3 and P3 treatments yielded significantly higher values of specific conductivity, NH4 – N, NO2 – N, and PO4 – P, and significantly lower values of dissolved oxygen than the other treatments. Zoobenthos population was low in all the treatments. The results suggest that application rate of 0.26 kg/m3 every 10 days seems to be the most suitable for Koi carp tanks manured with both cowdung (C2) and poultry excreta (P2), through maintenance of better water quality and greater abundance of plankton in the system. Suitable environment in C2 and P2 resulted in significantly better growth of Koi carp than other treatments.
(Aquaculture and Limnology Laboratory, Department of Zoology, University of North Bengal, District Darjeeling, West Bengal 734 430, India; email of S. Barat: sudipbarat@rediffmail.com)

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