Iranian Scientific Fisheries Journal
Year:2004 | Volume:13 | Issue:2|Papers Count:19

Recent rapid industrialization in developed and even developing countries and the resultant high demands for industrial products, has led to the need for easy industrial disposal. The cheapest method for such disposal during the past few decades has been by discharged of the effluents into the nearest river or lake. The extent of the resultant damage on the environment of water pollution from a variety of sources has given rise to great concern. Heavy metal pollution of the aquatic ecosystem could occur either from waste disposal or at mining and processing sites by the leakage of minerals into the rivers. Flood water from mines may also carry high concentrations of heavy metals into the rivers, and fish sperm would then be exposed to these metals. This study has been navigated to look at some ultramorphological changes of copper bioaccumulation on two teleost species.Sperm from carp and trout incubated with different concentrations of copper for 3 hours. The specimens were processed and morphological changes on sperms were viewed by scanning electromicroscopy. The results showed that copper at concentrations higher than 10 ppm insert extensive morphological effects on sperm (mainly enlarging sperm's head), so they cannot swim freely and fertilized ova. Mean percent of abnormal sperms were 75, 100 and 100% for 10,50 and 100ppm copper concentrations, respectively.

This study was carried out from April 1999 to March 1999. During this study 55 genus of phytoplankton were seen including: diatoms (Bacillariophyceae), dinoflagellates (Dinophyceae) and blue green algae (Cynaophyceae).The most population was seen in diatoms (25583 cells/lit), dinoflagellates (687 cells/lit) and blue green algae (75 cells/lit), respectively.The highest record of diatoms was seen in winter (66922 cells/lit), but blue green algae were dominated in summer (157 cells/lit).The highest population of phytoplankton was seen in during June in surface water of eastern creek (156660 cells/lit).In statistical study, difference between stations of two branches of creek (east branch and west branch) wasn't significant.

Histological study of alimentary canal of Persian sturgeon was conducted during early life from hatching to 56 days old by light microscope. Some hours after hatching, in anterior part, rudimentary eye and brain were visible, also in posterior part was completely filled with acidophil yolk. Mouth and anal were not clear. In 5-7 days after hatching all parts of the alimentary canal except stomach were roughly anatomically complete, as though in comparison with the hatching time the amount of acidophil yolk was less. At this stage, mouth was covered by stratified squamous epithelium in which several number of tast buds were visible and also rudimentary part of esophagus was squamous to pseudostratified columnar epithelium and in terminal part was columnar to ciliated pseudostratified columnar epithelium. In 8-9 days after hatching, the alimentary canal was structurally complete and two parts of stomach i.e. glandular stomach (cardia) and non-glandular stomach (pyloric) were more clear. The glandular stomach epithelium was simple columnar to ciliated pseudostratified columnar epithelium, while pyloric stomach had simple columnar to pseudostratified columnar epithelium. In 9 days after hatching, external food with a lot of yolk were visible in alimentary canal, which indicates endo-exogenous feeding. In I I-12 days after hatching a lot of external food i.e. daphnia were visible in alimentary canal .In 14 days after hatching pyloric caeca was appeared and in 40 days conical teeth was observed. In the primitive stages of life, the glycoprotein secretions belong to simple columnar cells (interior part of esophagus &some parts of intestine), while through age increase, this secretions belong to apical cells of simple columnar and also goblet cells. The beginning of active feeding of Persian sturgeon larvae was occurred in 9 to 11 days after hatching. Following the development, there was no special alternation except thickness increase of epithelium, muscular layer, connective tissue of lamina propria and increase of epithelial folds of intestine.

The effects of added artificial substrates on juveniles of Indian white prawn (Penaus indicus) were evaluated. Three replicate tanks were randomly assigned to receive added substrate to increase available surface 20, 40, 60 and 80 percent. Control tanks received no added substrate. Juveniles with mean weight of 0.42±0.027gwere raised for 90 days in 5000 lit concrete tanks filled with 4000 lit of water and stocked at a density of 30 ind/m2. Growth and survival of P. indicus juveniles were studied during the culture period.Results showed that substrates significantly (P<0.05) affected growth performances of Indian white prawn. Highest specific growth rate (SGR) and highest yield obtained in tanks with 40% added substrate in compare with other groups. Carapace length gain and survival rate had not significantly differences (P>0.05).

Due to approaching the method of marine algae (G. corticata) mariculture in the Chabahar waters (located at NE of Oman Sea), a series of feasibility studies were carried out to identify the suitable areas for growth of this algae. In this regard, different regions of shallow waters, intertidal zones, and also natural habitats of them were selected for either collecting sample or as culture regions.During the growth periods in autumn, winter and spring (the culture and plantation were not carried out during summer time synchoronized with monsoon season). Some acceptable results were achieved that indicated the meaningful growth rate of plants in the selected stations.According to the obtained results, at the end of culture period the weight growth was 3 times more and the mean length growth of C. coricata talls was from 68 to 134mm at the end of culture period. On the other hand, this statistical analysis didn't show any significant differences in different seasons from point of weight growth.It should be mentioned that some physical and chemical factors of sea water were measured consist of salinity, temperature, DO., pH, nitrate, phosphate and turbidity.

In the present study 959 specimens of Capoeta capoeta gracilis were studied for their helminth parasites in two sampling areas in Shiroud river. Samplings were carried out during one year from January 2002 to January 2003. Nine species of parasites were identified namely: Clinostomum complanatum, Diplostomum spathaceum, Posthodiplostomum cuticola, Allocreadium sp. (trematoda), Dactylogyrus pulcher, Dactylogyrus lenkorani, Gyrodoctylus mutabilitas (Monogenea) Rhabdochona fortunatowi, Capilaria sp. (Nematoda).The Capillaria sp. was found only in one sampling area. There are significant differences between the abundance and prevalence of Rhabdochona fortunatowi, P. cuticola, C complanatus, D. spathaceum, Allocreadium sp. In two study areas, prevalence, abundance, species richness, diversity equitability and similarity indices were compared between two study areas and the significant differences are discussed.

In this survey two species of chlorophyta (Chlorella vulgaris and Scenedesmus obliquus ) and one species of blue-green algae (Anabaena flos- aquae) were exposed with heavy metal (zinc) under lab condition ( temp. 25± 2°C,light 3500± 350 lux) for 96 hours. After this time, these species were counted with hemocytometer and based on probit analysis method and was determined ECIO, EC50 and EC90. Amount of EC50 for C vulgaris, S. obliquus and A.flosaquae were 0.134,0.047 and 0.093 mg/lit, respectively and this subject was distincted that S obliquus has more endurance than other species.Mac value of zinc for these species (C. vulgaris, S. obiquus and A.flos-aquae ) were 0.0134, 0.0047 and 0.0093 mg/l respectively. Regression coefficient was 92-98 percent between concentration logaritm of zinc and decrease of these species density.

The present experimental research was carried out to study the histology the inflammatory response and circumstance of wound healing process in the inflicted skin and underlying muscle of common carp.A number of 30 fishes with average length of 22cm in a recirculating glass aquaria system, at an average temperature at 27°C, were used for this study.A surgical wound (1.5-2.0cm long x 0.5cm deep) without complication of secondary infections, was made by sterilized scalpel blade into the left dorsal muscle of each anaesthetized fish. At least one wounded fish was sacrificed and sampled at 30 minutes, I, 2, 4, 6, 8, 10, 12, 24 hours and thereafter at 2, 4,6, 8, 16, 24, 32, 40, 50 and 60 days after wounding. The samples were fixed in 10% buffered formalin and 5µ sections were prepared using standard histological method. The sections were stained by the standard H&E staining method. Also periodic acid schiff (PAS) with tartrazin were used for specific tissue features. The stained sections were examined using light microscope.Re-epithelialization of wounded epidetmis was completed within 4 hours after wounding. Macrophage infiltration began at 2 hours, and myophagia at 6 hours. Fibroplasia and muscle regeneration were initiated at 2 days after wounding. After 16 days, epidermis was normal and dermis was completely linked. The wounded area restored its main components by 16 to 24 days after wounding. This study revealed that a healthy carp is able to have a rapid and effective inflammatory response and also high potential of repairing against surgical wound.

Light impact on growth of Skeletonema costatum at 20 treatments of light regimes including combination bf five intensities of 2000, 4000, 6000, 8000 and 10000 lux and four periods of (LightDark) 24:0, 18:6, 12:12 and 6:18 hours was studied. Daily random sampling was done for all treatments to determine cell concentration and growth rate. Among different light periods, growth rate was maximum and cell concentration was minimum at continuous light. At 4000 lux growth rate was higher than other intensities. However, there were not significant differences between treatments for growth, except 6:18 h (L:D); in this light period at different irradiances, growth rate and cell concentration was very low, and this made a significant difference between these treatments and others. The results showed that S. castatum's active cells adapted to light changes very well. But in older cells, i. e. the cells at late stationary phase or at death phase, there might be some growth disorders caused by environmental parameters, before active growth begin.

The shrimp farming success in the future will greatly depend upon increasing supplies of healthy and high quality seed for stocking ponds. The limited and inconsistent availability of wild shrimp postlarvae together with an urgent need of establishing selective breeding programs, increased the interest in captive broods of penaeids. Many investigations have been carried out on several shrimp species world-wide. This study has been conducted on 3 shrimp groups since September to July 1999 in Bandar-e-Imam southwest Iran. The wild group (SPB) prepared from jask area and the pond group (POB) prepred from artificial ponds upon. harvesting them as marketable size have been investigated. 2 groups were exposed to natural diets consisting of squid and artemia biomass in same conditions using 12 m33 concrete tanks. Stocking density was 2 piece/m2 (1F:1M). Half part of the pond bottom covered by fine sand to reduce the stress where the other part has been used for feeding. Daily ration given in 3 times by satiation method. Also reproductive performance of wild gravid brooders (WLB) were recorded as a control group. 2 examined groups well and around 30% of POB females successfully ripened an produced eggs and nauplii. Almost all males of both groups were matured. Data showed fecundity is highly correlated to the TL and W of the brooders by positive trend. Considering the TL, W, fecundity and nauplii production the WLB brooders are significantly (P<0.05) higher than 2 other groups, while the SPM brooders are significantly (P<0.05) higher in hatchability. Meanwhile the survival rate from nauplii to postlarvae stage was around 30% for SMP brooders. On the other hand the growth parameters (TL,W) of the marketable size of the shrimps produced from SMP brooders were significantly (P<0/05) higher than those produced from WLB group. Since the fecundity is important by increasing the brood size thus the data suggest the superiority of the SPM brooders.

This research was carried out to study the feeding behaviour of Blue Swimmer Crab (Portunus pelagicus) in Hormuzgan province waters from October 2001 to December 2002. Samplings were done in different methods by presence on research vessels, fishing vessels and dhows in addition to collect the samples from stake-nets. 490 stomach contents were observed under steriomicroscope in which among them the number of full, semi-full and empty stomachs were 136,197 and 157, respectively. The food contents were classified into 4 main groups namely; fish, mollusc, crustacean and plankton. The Index of C.V. was estimated 32.04 . This figure shows that blue swimmer crab can be assumed as a gluttonous species.

The frequency and distribution of meiobenthoses in northern Creeks of the Bushehr Province during autumn2000- Summer200I were studied for determining the condition of sea sediments using seasonal sampling.Samplings were carried out in 10 stations from Doube Creek to Bandar Genaveh Creek as well as a control station in the Persian Gulf. Totally, 4 taxa of meiofauna were identified that Ostracoda and Gastropoda with 29% and 18% had the maximum and minimum percent of abundance, respectively. The maximum percent of abundance in station No.10(control station at sea) with 20735 n/m2 and the minimum abundance in station No.2 (Creek of Farake)with 5320 n/m2 were observed. The maximum abundance of meiobenthose in spring with 167603 n/m2 and the minimum abundance during winter with 61365 nlm2 were determined. In addition, grain size, soil texture and total organic matter (T.O.M) of sediment in 10 stations were analyzed. Results showed that station No.10 with 11.79% had the maximum percent of T.O.M while the minimum T.O.M (3.87%) in station No.4 (Gasir Creek) was observed. The correlation of sampling station based on the abundance of meiobenthose was also analyzed.

Makoo dam lake made up in 1998, to providing agriculture water, prevention of flood water and production of electric power. It is placed in 12 km to south of Makoo city 29° 44' minute E and 39°11' N). Feeding studies occurred by using of fishing gear, include of electro fishing, gill net and beach seim, seasonally. Fish caught was in size range of 27-290 mm and 0.4- 327.7g.Maximum and Minimum of feeding intensity was in winter and spring, respectively. Its average was 360, that showed feeding of this fish was approximately optimum in this lake. Whereas maximum and minimum of K-factor was in summer and winter, respectively. C. capoeta is a detritovorous. Therefore, it consumed from so much other food items, a.g. phytoplankton and benthos in this lake. From phytoplankton, phylum Chrysophyta and genus cyclotella from benthos; Chirooomidae and Ephemeroptera have the most important food sources. With attention to limitation of food organisms of benthos, it is not recommended introducing of other benthopelagic fishes in Makoo lake.

Zayandehrud is located in central of Iran. It is important habitats for living organisms and has a main role in diversity of flora and fauna too. Eight stations from Zayandehrud bridge up to Khajoh bridge were selected to determine Mulloscian assemblage. Malcological studies led to identification of I pelecypoda species (Corbicula fluminalis) and 4 Gastropoda species (Lymnae gaderosina, V. valvata piscnalis, Physa acuta and Physa sp.). All of Gasteropoda species belong to Hycanian province and only Pelecypoda belongs to North Africa and Western Asia fauna.