مجله علمی شیلات ایران
سال نوزدهم شماره 1 (پیاپی 70، بهار 1389)

Feeding behavior of yellowfin seabream larvae during the first two weeks of larval life was studied by feeding larvae on different ratios of live food and microencapsulated diet (MED). Food consumption rate increased progressively with increasing larval weight. The results from visual observation of the larval guts under a light microscope indicated that yellowfin seabream larvae were able to ingest and digest MED from the onset of exogenous feeding.Comparing the average number of rotifers and MED ingested by larvae in treatments including either only live food or MED did not show any significant differences (P>0.05). In addition, the gut contents examination from the larvae fed simultaneously on both rotifer and MED, revealed that the larvae's tendency towards live food and/or MED was a function of live food density in the rearing tanks. The larvae preferentially ingest live food even when these are present at a very low concentration in comparison to MED. The mouth diameter of larvae has a strong influence on the amount of ingested rotifers and MED.There was a significant positive correlation between larvae growth and the average number of both live food and MED ingested by larvae in this trial (P<0.01). Although larvae survival rate had a positive correlation with the number of rotifers ingested, the amount of MEDin the larvae's gut did not show effect on larvae survival rate (P>0.05).

Crabs of intertidal zone of a muddy shore in Bandar Abbas were studied using monthly examination of Goharshad and Terminal stations during August 2005 to July 2006. Sampling was done by Corer and 14 species from 6 families were identified. Crabs were from Ocypodidae, Pinnotheridae, Pilumnidae, Trapeziidae, Leucosiidae and Varunidae families.Results showed Ocypodidae, the most abundant and diverse with 1196 individuals/m 2,was more abundant but less diverse in Goharshad station compared to Terminal which could be attributed to the urban pollution in Terminal station. Pinnotheridae with 64 individuals/m 2 showed an adaptation to organic materials but was not resistant to being out of water. Pilumnidae and Trapeziidae were found in small numbers in the stattions. Genus Ebalia from Leucosiidae with 27.18 individuals/m 2 showed positive reaction to organic materials and was resistant to being out of water. Varunidae were present with a few specimens probably because of human disturbance or speed in burrowing and escaping from sampling. Because civic pollution enter Terminal station, The results of this research showed that crabs react to urban pollution and hence are suitable as environmental indicators.

Data used in this publication is a part of a comprehensive study was carried out jointly between South Aquaculture Research Center (SIARC) and Kuwait Institute for Scientific Research (KISR) on silver pomfret (Pampus argenteus) in 2003 to 2005. The study was aimed to collect efficient data from two regions from biological and population parameters of this economically important fish to properly explain its stock situation and ultimately leads to improve a better management program for conservation of stock and yield sustainability. Monthly data collection on length and. biology, started since May 2003 and ended by December 2005. Shrimp trawl and gill nets were used for sample collection from the predicted areas in both sea regions. FL of the fish was within the range of 12-34cm, with the dominant length of 18-25cm in Kuwaiti waters. In Khouzestan waters fork length was ranged 14-22cm for the years of2003 and 2004 but 14-26cm for 2005. Strong relationship betweenlength and weight in both countries with a scanty difference was observed for this species (R2 =0.989 for Khouzestn, R2 =0.947 for Kuwait). The findings of present study are suggesting that silver pomfret is following an allometric growth pattern in studied area. Spawning of silver pomfert begin in July and continue till October in Kuwaiti waters but in Khouzestan waters the heights spawning of this fish started in end of May till October. Length at first maturity of this species in the studied area of Kuwait was found to be 19.6cm FL based on Spearman-Karber method but 23.3cm (FL) based on the logistic model. The parameter was estimated 20.0 c (FL) in Khouzestan waters according to the logistic model.

This paper presents the levels of total mercury (T-Hg) in dorsal muscle, liver and spleen of pike (Esox lucius) from Anzali Lagoon in Iran. Sampling were carried out from July 2004 to July 2005. In addition 78 samples were collected. T-Hg concentration were calculated in relation to biometric factors. T-Hg was measured by the LECO AMA 254 Advanced Mercury Analyzer (USA) according to ASTM standard NoD-6722. Each sample was analyzed 3 times. Accuracy of T-Hg analysis was checked by running three samples of Standard Reference Materials; SRM 1633b, SRM 2711 and SRM 2709. Detection limit was 0.001mg/kg in dry weight. The minimum and maximum concentration ofT-Hg in dorsal muscle was 0.2ppm in one year and 1.2ppm in five year class. The mean T-Hg significantly increased wit age increased (P<0.05). The T-Hg mean concentration. In 1 and 2 year classes was 0.171ppm. Accamulation pattern ofHg was significantly as well as muscle>liver>spleen. T-Hg content in females was higher than males (P<0.05). Acceptable monthly intake without carcinogenic effects due to mercury for women, men, juveniles and children was 270, 320, 125 and 59g per month. Consumption of pike above 35cm. length should be avoided.

Keywords: Pollution, Heavy metals, Pollutant, Mercury, Esox lucius

Killifish (Aphanius sophiae) of the Cheshme-Ali of Damghan and Shour River of Eshteherd were studied and compared from morphological point of view. For morphometric studies, 34 Truss morphometric measurements and 10 traditional measurements were made for each individual. Nine meristic traits were counted. Multi-variate analysis of variance (MANOVA) revealed a significant different between variables (P=O.OOO). Sexes and populations were using multi-variate analysis techniques such as Principle Component Analysis and Discriminate Function Analysis based on morphometric variables. These variables seem to be under the influence of environmental factors such as temperature, salinity and feed condition. However, no separation was achieved based on meristic traits.

The silver carp (Hypophthalmicthys molitrix) compnses about 50% to 85% of the composition offish species in the polyculture system of warm water species in Iran. However, the difficulty in preparation of this species and the presence of pin bones are among the main reasons to restrict the demand of this species in the domestic markets, particularly in non­ coastal provinces. The objective of this study was to identify parts with less and/or no bones in silver carp fillets. The shape, size and location of bones found in the flesh were studied by three

Enzyme digestion, cooking in hot water and X-ray scanning. Results showed that except vertebral bones and ribs, the thin bones found in different parts of the flesh can be categorized into three groups: Pin shaped, Y shaped and non-regular shaped (several bifurcations). On the basis of density and arrangement of bones, we found that the fillets are made up of three different layers: External layer mostly of dark muscles and lipids with no bones, middle layer with the highest density of bones and the int mal layer which comprises about one third of the depth of fish flesh. The shape and arrangement of the bones in fish tail was significantly different. On the basis of recent findings, the deep part of the back and a narrow band on the upper part of the back are considered as boneless parts in silver carp.

Silver ion and hydrogen peroxide act synergistically as a strong disinfectant. The purpose of this study was to assess the effect of combined hydrogen peroxide 50% and silver ion 0.05% at four life stages of Indian white shrimp (Fenneropenaeus indicus) and to evaluate the feasibility of using this substance in shrimp culture. The Trimmed Spearman-karber software was applied for determining ECso/96h and LC5o/96h with 95% confidence limit on the 6000 shrimp based on OECD static method.The experiments were conducted in Iran Shrimp Research Center, Bushehr, during 2005 -2006. The ECso values of 132.5, 67.89, 55.56, 51.95 and 48.6ppm were obtained in PL 15 stage after 12, 24, 48, 72and 96 hours, respectively. Also these were 147.57, 70.83, 60.01, 54.89, 41.19 for PL45 stage, and 306.43, 174.14, 113.62, 78.21, 61.96 for sub adult stage (12±1 grams), respectively. In addition, the EC5o values of243.25, 130.55, 75.56, 61.18 and 51.59ppm were obtained at adult stage (20±2 grams), respectively. The LC50 values of239.81, 101, 74.28, 65.72 and 61.45ppm were obtained in PL 15 stage after 12, 24, 48, 72 and 96 hours, respectively. Also these were 304.56, 160.12, 113.1, 93.69, 79.38 for PL4s stage, and 712.13, 518.44, 265.29, 145.53, 103.76 for sub adult stage, respectively. In addition, the LC5o values of 827.75, 508.91, 317.3, 139.44 and 85.88ppm were obtained at adult stage, respectively. The statistical results showed that the "no observed effect concentration" (NOEC) of this substance was 20ppm, and the "lowest observed effect concentration" (LOEC) was 40ppm, thus "maximum allowable concentration" (MAC) value was determined 28.8ppm on the Indian white shrimp. Therefore this combined chemical should be used under determined MAC value with a complete precautionary as a disinfectant for Indian white shrimp.

Stock assessment and the opening and closure seasons of the green tiger prawn were surveyed in Bushehr waters from July 2004 to September 2006. The study area encompassed Motaf area (27° 30' N" and 51° 30' E) to Daylam waters (30° 00' N and 50° 00' E) the northern part of the Iranian waters of the Persian Gulf. Assessment was conducted using 45 stations on 15 transects in water depths less than lOrn, 10-20m and 20-30m. Sampling was done by bottom trawl net.Results showed that the shortest mean length of the prawn were 11.3, 11.8 and 11.9cm in the years 2004, 2005 and 2006, respectively. Also, the maximum catch per unit effort for the prawns in these years was found to be 10.8, 14.7 and 9.7kg per hour.At the opening of fishing season in the years 2004, 2005 and 2006, the CPUE of the prawn fishing launches were 100, 150 and 120kg per day.Based on length frequency of the green tiger prawn, the opening times of prawn fishing was proposed to be 22, 11 and 20, August of years 2004, 2005 and 2006, respectively. Also, the closure times were derived from the shrimp commercial catch data and defined to be 25, 27 and 28 of September in 2004, 2005 and 2006, respectively.Investigation of the shrimp stock density in Bushehr waters hows that the green tiger prawns enter the fisheries areas from the southeastern parts of Bushehr waters. The Motaf, Nakhilou, Ras-e-khan and Mond River are the areas that green tiger prawn schools are first emerged in the Bushehr province waters.

Surimi is a high quality myofibrillar protein concentrate that is obtained from cheap and underutilized fish species. In this research, surimi burger was prepared from Sarm (Scomberiodes commersonnianus) surimi (60%) and other ingredients. Some quality attributes of surimi burger were investigated during 3 months of frozen storage at -20°C. Fat value was determined in fresh raw surimi and surimi burger. Physical properties such as color stability (L, a and b values) and textural hardness before and after cooking were determined for surimi burgers during frozen storage at -20°C. Results showed that the hardness of surimi burgers and cooked samples were 768gf and 204gf, respectively at-the beginning of storage, and it was increased at the end of storage (921gf for surimi burger and 462gf for the cooked sample). Hardness showed significant difference through storage (P<0.05). No major change was observed in the "L" value in surimi burger after 2 months; however it was decreased significantly after 3 months of frozen storage. In addition, no significant changes were observed in the "a" and "b" values in surimi burgers during frozen storage (P>0.05).

The effectiveness of pituitary extract from Crucian carp (Carassius auratus Linnaes 1758) in inducing ovulation in Veil Tail Gold Fish (Carassius auratus gibelio Bloch 1783), was examined and the effect of maternal hormone treatment on egg quality in two types of fertilization (fertilization in aquarium and artificial fertilization), were evaluated in 22·c temperature. Fish were injected intrapritoneally with three doses of, 2, 3 and 4mg/kg B.W pituitary extract (PE). With increasing of pituitary dose, practical fecundity also increased from 1775 in control fish to 3201 in fish with 4mg/kg B.W ofPE. Mean time to ovulation was reduced significantly (P<0.05) from 132h in control fish to 13h in fish with 4mg/kg B.W. Ovulated eggs from fish injected with 4mg!kg B.W of PE had lower fertility and hatching rates compared to eggs from fish injected with lower doses and the control fish. The methods of fertilization had no significant effect on the egg quality. In conclusion, the results of this study showed that the pituitary extract of Crucian carp is effective in inducing and shortening of ovulation of Veil Tail Gold Fish and the suggested dose for this species is 3mg!kg B.W.