JOURNAL OF AQUATIC SCIENCES
Year:2010 | Volume:1 | Issue:3|Papers Count:7

Parasites are one of the known pathogenic agents in shrimps that affect on their host by direct or indirect manner. They caused stress on shrimps and this lead to growth and invasion of opportunistic pathogen agents. According to importance of pathogenic organisms in health and hygiene of cultured shrimp and the economy of this industry, research on parasitic fauna of cultured shrimps were collected has important aspect. In this Survey 120 juvenile and adult Fenneropenaeus indicus shrimps from rearing ponds of Delvar, Helle and Mond sites in Bushehr province. Gill, appendages, hepatopancreas, midgut and muscles of shrimps were examined by wet mount smear. The results showed the incidence of parasites was 60.8% in shrimp cultured ponds. The most prevalence and intensity belonged to zoothamnium sp. (prevalence 55.83% in appendages, 19.2% in gills), Epistylis sp. (prevalence 20% in appendages, 1.67% in gills) and Vorticella sp. (prevalence 2.5% in appendages, 0% in gills) respectively and no helminth parasites and endoparasites were observed in studied shrimps.

This research was carried out to product the neomale monosex population of molly fish (Poecilia latipinna) with consuming oral type of 17-a methyl testosterone hormone in two experimental groups of brood and fry molly fish in eight treatments (group one: 0, 100, 200, 300 mg hormone / kg food and group two: 0, 300, 400, 500 mg hormone / kg food) for 60 days. At the end of the experiment period, histological and morphological studies along with calculating amount of diurnal growth (ADG), special growth rate (SGR), mortality rate, neomale production percent, sterilization percent and mixed sex percent was carried out to determine the best dose in commercial production. The results showed that second treatments of each exam (B=200 mg hormone and F = 400 mg hormone / kg food) had the best ADG and SGR, the minimum mortality, maximum level of masculinization in morphological view and 90% of neomale populations in histological view. These treatments produced maximum neomale monosex populations and were economic and useful, while the third treatments of each exam despite of having 100% masculinization rate based on morphological studies, had high mortality and 60% masculinization rate based on histological studies.

This research was carried out to improve water quality in aquariums containing Oscar fish using lettuce and aquaponic system. The tanks with lettuce had two treatments and each group had three replicates. 60 oscar fish effluent was spilled into the first group tanks and the municipal water was spilled into the second group tanks. Factors such as nitrate, ammonia, turbidity, electrical conductivity and pH were measured at 0, 5, 10, 15, 25 hours after entering effluent and municipal water into tanks. Obtained data have been analyzed with statistical test of ANOVA and Duncan. Results showed that lettuce plant caused decrease of ammonia and nitrate and the best results were observed in a 24 hours period. It is concluded that lettuce plant in a aquaponic system using Oscar fish effluent can be used in water quality optimization for reusing in fish rearing system.

Sefidrood River is the largest river of Iranian coast of the Caspian sea which is the place of spawning for most migratory fishes of Caspian sea. LAS detergent pollutions in this river water were investigated seasonally during 1999 and 2000. Thirty two samples were extracted by liquid-liquid extraction method (chloroform-blue methylene) and detergent concentration was quantified using spectrophotometer UV. The average concentration of LAS was less than permissible condition of WHOM. The mean level of detergent was 0.031 ppm and the maximum level in 1999 and 2000 was 0.049 and 0.046 ppm respectively. The statistical comparison between stations and seasons showed no significant differences (p>0.05).

In this study, 67 sample of Squalius cephalus were caught during one sampling in summer 2010 including 36 sample from Gamasiab river in Hamedan province and 31 sample from Talar river in Mazandaran province. In this investigation, 27 morphometric and 9 meristic characteristics were studied. Obtained data were analyzed in SPSS 16 software and by T-test and PCA. According to given results, average of variations coefficient of morphometric and meristic characteristics for Squalius cephalus in Gamasiab river were 34.82 and 7.33 percent and in Talar river were 20.48 and 6.26 percent respectively. Morphometric characteristics corrected and standardized before analyzing because of decreasing of error resulting from allometric growth. 10 factors for morphometric characteristics and 4 factors for meristic characteristics accounting for about 81.37 percent and 66.84 percent of traits biodiversity respectively were selected within these two rivers. Also, in these two rivers Squalius cephalus had significant differences (p<0.05) in 27 morphometric traits and 4 meristic traits. In obtained results from PCA method, distinction of populations was not observed and they had relatively low overlapping.

The parrotfish (Scaridae) are a family of marine tropical fish distributed in the Indian, Pacific and Atlantic Oceans. They are characterized by fused teeth and bright colours which make them known as parrotfish. In the present research, morphology of urohyal bones in two species of parrot fish, Ghobban scaru Forsskal, 1775 and Persicus scarus Randall & Bruce, 1983 (Scaridae) has been studied. Results showed that the urohyals were varied in ventral shape, presence and number of processes in the anterior part, origin of dorsal keel (distance from anterior tip), groove in ventral portion and some other character. These urohyal morphological variations could be easily used in identification of these two morphologically similar species. The differences may be attributed to the habitat and habits differences of these two coral reef species.

In this study, histology of some of rainbow trout (Oncorhynchus mykiss) internal organs involved in fish metabolism and immune system was studied. To do this, spleen, liver and anterior intestine of rainbow trout were examined using light and electron microscopy. Results showed that spleen is covered by a loose connective tissues consisting of mesothelial cells. Spleen paranchyma is divided in two white and red pulps in which the white pulp is dominated. Mesenchymal cells have large chromatic nucleus. Lymphocytes are related to each other by their cytoplasmic processes. Liver has a mesothelial cell layer externally. Liver cells in lobules are irregularly arranged in rows and the lobules are separated by sinusoids. Liver cells with two nucleus, rough endoplasmic reticulum and bile ducts with diverse sized microvilli are observed. Anterior intestine sections revealed mucosal layer muscular layer, goblet cells and microvilli. Mucosal cells in the anterior intestine contain abundant rough endoplasmic network and mitochondria.