NEW TECHNOLOGIES IN AQUACULTURE DEVELOPMENT (JOURNAL OF FISHERIES)
Year:2014 | Volume:8 | Issue:2 (30)|Papers Count:11

In this study, some biological and ecological (i.e. age and reproduction) characteries of populations of Capoeta trutta in Gamasiab River in Kermanshah Provience was studied from August 2008 to June 2009. During this study, 252 specimens were caught using Cast net and Gill net. Totally, five age groups (1-5 years) were identified. Sex ratio was 1.96♂: 1♀. In this study, it was revealed that in age, length and weight frequencies in female fish were longer and heavier than male fish (except, for male of 1 year). Mean condition factors of fish Gamasiab River were 1.22 There was significant difference between male and female fish (P<0.01). Mean GSI of fishes were 3.64. Mean absolute fecundity in female fish was 7756 egg number per weight fish. Rang egg diameter in this study was 0.12-1.90 mm.

This study assesses Total Factor Productivity (TFP) and its component in fisheries sector, trout farms in Fars province, Iran. All data were collected from fisheries organization government, including a number of 33 farms between 2009 and 2010. Malmquist index was applied to calculate TFP and its effective factors. In addition, technical changes and technological changes including management and scale efficiency was employed. Considering the environmental factors, input-oriented assumption was used. The results represented that 36.4 percent of farms are technically efficient by using Constant Return to Scale (CRS), 75.8 percent of them by using Variable Return to Scale (VRS) and 69.7 percent by using Free Disposal Model (FDH). Furthermore, the range of variation of TFP index is between 0.38 and 2.09, averagely 1.12. The region has remarkable potential for productivity development due to the present outputs. According to the results, determined reduction in inputs without changing in production and having strategic attitude is suggested. Some drastic changes in the processes of production such as insuring the farms can be applied as well.

The aim of this study was determination of abundance and biodiversity of phytoplankton community at integrated fish culture of adult and fingerling fishes with together at East of Golestan Province, at Gonbade Kavous city. Sampling were done monthly from June to November 2011. Samples preserved with 2-4% formalin and transfer to the laboratory for study with light microscope. Finally, 7 groups and 39 genus were identified. Between recorded groups, 18 genus belong to Chlorophycea, 10 genus belong to Cyanophycea, 6 genus  belong to Bacillariophycea, 2 genus belong to Euglenophycea, 1 genus belongs to Dinophycaea, 1 genus belongs to Chrysophycaea and 1 genus belongs to Charophycea. Highest of total density belong to Chlorophyceae, Cyanophyceae and Bacillariophycea with 228.9, 110.9 and 79.5 (cells/ml), respectively and lowest of total density belong to Charophyceae, Chrysophyceae, Euglenophyceae and Dinophyceae with 9.6, 7.4, 2.5 and 1.8 (cells/ml), respectively observed during 3 ponds. According to the results, sum of dominance genus density of total groups equivalent 64% of total density. This study showed that density and diversity of phytoplankton community affected by physico-chemical factors. We suggest that intensive and semi-intensive warm water fish culture system with mix of adult and fingerling fish at Iran can will be done with high economic and efficiency level.

Before each study in Caspian Sea, ongoing ecological study of the Caspian Sea, especially the distribution and identification of species composition, density and biomass, regional and seasonal variations in phytoplankton appears necessary. Due to various physical and chemical factors of rivers leading to the sea and bed topography, it seems initial production rate in the different seasons and stations are different. This study done in 2010-2011 through spring, summer, autumn and winter, in 32 studies from 8 transects (Astara, Anzali, Sefidrood, Tonekabon, Noshahr, Babolsar and Bandar Turkman). In each transect, it have chosen 5 stations were sampled quarterly from the zero depth (level), 10, 20, 50 and 100 m by Niskin sampler. In totally, 81 species of Bacillariophyta identified. Studies showed that Shannon index for Bacillariophyta was different in different seasons and stations.

This study was carried out to evaluate the quantitative and qualitative variations of phytoplankton community during 4 months (April, May, June, July) in earthen ponds of warm water fishes with different phytoplankton production potential (weak, fair, suitable) according to the filed observations by the workshop specialists. Results indicated that amongst identified phytoplankton phyla during rearing seasons, the highest and the lowest percentage abundance (%) were belonged to Cyanophyta (54.48%) and Chlorophyta (0.67%), respectively. The most and the least values of phytoplankton diversity were observed in April with 41 genera and May with 27 genera. Analysis of monthly changes in cell abundance of genera from different phytoplankton phyla revealed no significant difference. There was no significant difference among phytoplankton abundances of each phyla in different rearing earthen ponds (P>0.05). Moreover, no significant difference was detected among cell abundances of different sampling months in each pond (P>0.05). Biodiversity indices analysis (Shannon, Simpson, Margalef and Evenness) showed no significant difference among various sampling months and different rearing ponds as well (P>0.05). These findings confirm undesirable condition in phytoplankton load of rearing ponds and their contamination to organic matter during the studied months.

The main objective of the present study was to determine spatial and temporal distribution of mullets by using bottom trawl in depths 10-100 m in Iranian waters of the Caspian Sea, during 2008-2011. During 8 surveys the catch and CPUE (catch per unit effort) of mullets had a decrising trend. The total catch of mullets declined from 3064 kg in spring 2008 to 93 kg in winter 2011 and the average (±S.E.) of CPUE were 63.8 (±17.77) and 2.9 (±1.58) kg/0.5 hr-1, respectively. The spatial and temporal distribution showed that most of mullets concentrated in depth <20 m, in central and eastern Caspian in spring and the maximum CPUE was 152.8 (±73.26) kg/0.5 hr-1. In summer, the CPUE declined that the maximum was 10.0 (±2.74) kg/0.5 hr-1 in depths <20 m, in eastern coastal zone. In autumn, due to the migration of mullets to south Caspian, the CPUE increased sharply (the highest CPUE was 136.0±26.38 kg/0.5 hr-1 in eastern region). In winter, the concentration of mullets declined again which the maximum CPUE was 41.7 (±7.73) kg/0.5 hr-1 in depths <20 in eastern region. Acording to the present study, most of mullets concentrated in depths <20 m in all seasons. For wintering, mullets migrate to Iranian coastal zone during autumn and subsequently the commercial catches of the species increase.

The Polynemidaes is one of the great importance demersal fishes in the Oman Sea that research about them seems to be necessary. This research was down with the research trawler (Ferdos 1). The area was researched is from field (58 o55') to the Goiter Gulf (61 ْ 25') and depth of 10 to 100 meters that all of them are 1164 square mile of the sea. This area divided from west until east to the 5 regions (A, B, C, D, E) with 30 minutes of longitude and every area with deep layer of 10-20 meters, 20-30 meters, 30-50 meters and 50-100 meters were determined. In all of research, the number of station determined and the catch sampling with the trawl in one hours was down then the statue of the spices per unit area (CPUA) and the biomass of Polynemidaes separately in ever deep layer was estimated that the maximum average in per unit for one spices in one layer corresponding to the Polynemidae five filament in layer B with 8387.25 Kg and the least (minimum) average related to Polynemidae six filament in layer D with 1.02 Kg in square mile. The six filament spices in layers E and C not exist and the spices (Eleutheronema tetradaytylum) its maximum value in layer E with 571.78 kg in square mile. Although the average index in per unit based on deep layer indicated that Polynemidae six filaments (Polydactylus sextarius) with 1 kg at the depth of 20-30 meter have minimum and with the 5358 kg at the depth of 30-50 meter have maximum value catch. The value of the critical p for comparison of the catch spices in per unit (CPUA) indicates that Polynemidae with filament (P. plebeius) in the layer and the normal (general) Polynemidae in the depth layer have significant different but this significant various not exist in layer but in depth have significant different for polynemidae six filament. According to the calculated CPUA, the result showed that there is a schooling stock of Polynemidae in deep area of 30 to 100m (Biyahi to the head of Meydani) in the region.

Green tea extract which contains high amount of poly phenols is known as effective anti-oxidants due to anti-bacterial and anti-virus effects of poly-phenols. The main objective of this study was to compare the effects of lowring temperature (3-5 oC), Green Tea Extract (GTE) (800 ppm) and Modified Atmosphere Packaging (MAP) (condition 50:5:45 for N2:O2:CO2) with normal or Aerobic packaging (AP), on the chemical and sensory characteristics of SCM within refrigerated storage. Results of Peroxide Value showed that all treatments can effectively protect SCM against oil oxidation, compared with AP, after 4 days. Using MAP and/or GTE treatments reduced the Free Fatty Acid (FFA) formation ratio, because, in contrast with AP treatment, FFA increased significantely (P<0.05), only after 16 days storage. Thiobarbitoric Acid Reactive Substances (TBARS) of AP samples in 16th days was 2.51±0.21 mg that was upper than accepted limits. Effects of GTE treatment on TBARS increasing was not significantly different compared with AP (P>0.05). pH trends was ascending and GTE and MAP treatments had no significant effects on pH increasing. According to sensory evaluation, MAP had higher total quality score compared with GTE treatment and showed no significant difference with MAP+TE during storage. Combined treatment (MAP+GTE) was selected as an effective method that can extend the shelf-life of SCM up to 4 days at refrigerated storage.

Nowadays, popularity of rainbow trout, Oncorhynchus mykiss farming in the world has resulted in economic development and higher consumption rate so that it has made 2.4 billion dollars with 576000 tons production. Although this species is not among the most consumed fish in the world, but it has 1% of overall world seafood trade with 944 million dollars with its farming being 110 times its fishing; of this, 59.7% were frozen, 32.4% fresh and chilled and 7.9% were live. Iran has got the third place in production of this species with 10.8% of global production and 0.07% share in value and 0.1% share in global export. Analyses performed in the present paper showed that Iran had 72.7% fresh and chilled export and 27.3% frozen rainbow trout export from around 2.8 million dollars currency income from 2000-2008 in addition to high domestic demand.

This study was conducted to compare the morphilogical traites of Turkmenian and Kura varieties of Caspian roach using landmark-based geometric morphometric (GM) approach. A total 120 specimens from Gomishan Wetland in southwest and Talesh region in southwest of Caspian Sea were sampled. The left side of specimens were photographed and fourteen landmark-points were digitized on 2-D images using TpsDig2. Landmark data after GPA, analyzed using multivariate analysis including DFA, Ttest-Hotelling and CVA/Manova. Results displayed significant differences between the body shape of male and female of each population and also between two populations. Results also showed that Kura variety has bigger head, longer anal fin and deeper body depth than Turkmenian one. In addition, the result of this study found other body shape differences in relation to pervious studies. This cane be as result of better ability of GM approach to study the biological shape and precence of sexual dimorphism in Caspian roach. Morphological divergence between Turkmenian and Kura varieties can be related to evolutionary process of their body shape in respond to environmental factors of their habitat in the Caspian Sea.