Iranian Scientific Fisheries Journal
Year:2002 | Volume:11 | Issue:3|Papers Count:18

The LC50 of two anaesthetic agents, clove essence and MS222, on the cultivated fish species, Acipenser persicus, Oncorhynchus mykiss, Cyprinus carpio were estimated. 640 samples of above mentioned species were used exposing anaesthetic agents for 2 minutes. The LC50 of clove essence and MS222 for the sturgeon was estimated 297 and 291 ppm, for common carp was 271 and 272 ppm; and for rainbow trout was 199 and 207 pmm, respectively. Significant difference was found only between LC50 of MS222 in rainbow trout with LC50 of both agents in two other species. Also, the results showed that there is no significant difference on poisoning of two applied drugs in all above mentioned species; but with comparing different species, rainbow trout had lower tolerance to both anesthetics.

In this investigation, two hematological factors of hematocrit and hemoglobin and their changes regarding to different salinities were studied in common carp. Seven aquarium (with 100 lit. volume for each) were chosen and the water salinity of each one were adjusted to 0, 3, 6, 9, 12, 15 and 18 ppt, respectively. 16 specimen of common carp with 50-90 g body weight were added to the aquariums. The blood samples of fishes were collected in periods of 12 to 96 hour for further hematological measurments. The results showed that in salinity of 18 ppt, all fishes died after less than 12 hours. In stress condition, the minimum and maximum hematocrit index were found 13 to 45% and hemoglobin factor were varied from 5.0 to 12.2 g/lit.

The effect of a synthetic GnRHa on induced spawning of female rainbow trout broodstocks was examined. Some aspects of this experiment was sychronization and acceleratation of ovulation and the other was the control of quantity and quality of eggs. The fish samples were divided into 5 groups of 10 specimen. Injection were done interperutal and the dosage of GnRHa were 20, 30, 60 and 80 g/kg of body weight. Group 1 as control sample only received propylene glycol as a vehicle of hormone. The use of GnRHa injection could accelerate and synchronous ovulation and spawning in female rainbow trout, the mean time to ovulation was reduced from 19.6±2.45 days in control to 11.56±2.25, 12.75±2.72, 7.56±0.29 and 9.5±o.98 days in groups 2 to 5, respectively (p<0.05). Also cumulative spawning rate was increased in hormonal groups; up to 8thday after first injection. The cumulative spawning rate was 47.0, 34.4, 90.0 and 56.3% in groups 2 to 5 respectively. Although, until this time none of the females in control group were spawned. In the end of experimental period (day 26), this rate was completed in group 2 to 5, but only 50% of females in control group was spawned. The mean weight of stripped eggs, egg diameter and mean survival rate to the eyed stage did not show any significant difference between experimental groups (p>0.05). Testosterone levels were increased from 9.21±4.11 at time 0 to 23.47±14.29 ng/ml at 24 h after first injection, and then reduced to the basal levels in all hormonal groups (except group 5) at 72 h after first injection (10.91±3.11ng/ml) (p<0.05). There wasn't observed any testosteron levels fluctuation in control group.

A factorial experiment containing various protein and energy levels of diets was conducted for 60 days to determine the response of Indian white shrimp, Penaeus indicus, juvenile whit mean weight of 3.22:t0.04 g. Nine diets cotaining three levels of protein (35, 40 and 45%) and three levels of energy (350, 380 and 410 kca1l100g) were formulated and prepared in this trial. So this study was conducted with 9 treatments and thriplicate random groups of 20 shrimps per each 300-litre tanks. Each tank was filled with 200 lit. water and exchanged 50 precent every day. The shrimp were fed their respective diets as a situation with the feed divided into three parts for feeding at 08:00, 14:00 and 20:00 h daily. In this study, Ds (40:410) diet with P/E ratio of 95.7 mgp/kcal represent the notable performances for P. indicus. Furthermore, the present study showed that at constant protein levels, growth performances improved with increase in energy levels. The results of study also indicated at constant energy levels, weight gain, SGR, FCR and yield improved with increase in PIE ratio, but PER and NPU demonstrated a negative relationship between protein levels of 35 to 45. The proximate analysis and amino acid profiles of shrimp carcass did not show significant difference among the different diets.

Three main groups of macroalgae have been studied along 4 transects in Kish Island. Sampling were carried out during highest tidal time, bimonthly for one year. All sampling were made by applying quadrates (0.5xO.5m) randomly along the intertidal zone. The collected specimen were identified and their frequency and biomass were determined. Statistical results showed that Rizocolunium impelexum had the most frequency within green algae. Also, the most abundance occured in the first transect (Saffain), in the upper mid littoral zone (U.M.L) and during the first collection (March). Among the brown algae Cystoseira myrica had the most abundance in the first transect and medium mid-littoral (M.M.L.) in the fourth collection (September). Champia Japonica (red algae), had the most abundance compared to the other 13 species in the first transect and in medium mid- littoral regions (M.M.L). From the obtained information that in the first transect were located in the domestic sewage efluent region, the diversity and abundance of chlorophyta were the most. This can be due to existence and abundance of elements and nutrients. With the observation in the second transect (south western), algal species diversity especially brown and red algae were very high.

This research project was carried out during 1995-99 in three basins of Aras, eastern part of Urmieh lake and Ghezel uzan in order to identify fish species, preliminary study on ecology of the habitats and preparing a guideline poster and check list. The sampling was carried out seasonally by using the methods of electroshocker, castnet and seine-net with the mesh size of 5 mm. The samples were fixed and preserved in 10% formaline and transferred to the laboratory for further biological studies. Among the all identified fishes, there were 2 species and one subspecies belong to Barbus genuse, namely: B. mursa, B. capita and B. lacerta cyri. The subspecies of B. lacerta cyri had more abundance than two other species. Also, B. capita has big enough size as commercial value and sport fishing.

A series of research cruises were carried out in intertidal zones of Sistan-o- Baluchestan province in 1998. Four region of Gwatr, Chabahar, Tang and Galak were selected as sampling stations to collect samples from brown algae consist of: Sargassum glausescens, Cystoseira indica and Nizimuddinia zanardinii. This study was done monthly in one year period and recorded parameters were: density, freqency and biomass. The results showed that the mean relative density of Sargassum in Gwatr, Chabahar, Tang and Galak were estimated 22.17, 8.48, 6.74 and 7.74 %, and for Cystoseira indica were 43.18, 11.95, 22.37 and 37.71%, respectively. The algae of Nizimuddinia zanardinii was found only in two regions of Chabahar and Tang with 32.85 and 50.48% of relative density. The minimum frequency of Sargassum was found from May to August and for Cystoseira was from June to August with 12.5% and for Nizimuddinia was in August-September with 0.0%. On the other hand, the maximum frequency for three species were recognized from October to February with 100.0% frequency for Sargassum and Cystoseira; and 50.0% for Nizimuddinia. Also, the annual wet biomass in regions of Gwatr, Chabahar, Tang and Galak were estimated seperately for each species consist of: - Sargassum glausescens with 626.9, 117.8, 183.4 and 42.5 g/m2 - Cystoseira indica with 739.9, 95.2, 504.5 and 436.7 g/m2 - Nizimuddinia zanardinii with 1352.2 and 1208.5 g/m2 in two regions of Chabahar and Tang.

This study was conducted to determine some biological characteristics of migration population of roach, Rutilus rutilus caspicus, including age, growth and reproduction in Gomishan wetland from early November 1999 to early December 2000. The sampling were carried out monthly but in the peak of spawning period (late February to mid April) it was done weekly. The sex ratio was found M:F = 1.17:1.00 without any significant difference (even at 10% level); but the results of the sex ratio for each seperate age group showed significant difference (p < 0.0.5). A significant correlation was determined between total length, body weight, scale radius and age (p<0.001). Based on back calculation, the maximum growth ratewere found in ages 1+ and 2+. Gonadosmatic index (OSI) was age-dependent; with two peaks of late February and early March for males and late March and early April for females. The eggs diameter was measured with a range from 0.9 mm to 1.45 mm and the absolute fecundity was related to age.