فصلنامه بوم شناسی آبزیان
سال هفتم شماره 2 (پیاپی 702، پاییز 1396)

This study investigated the integrated effects of two photoperiods (16:08 and 08:16 h) along with three light intensities (3000, 15000 and 50000 lux) on some reproductive parameters and broodstock survival rates of Artemia parthenogenetica in six treatments in a completely randomized factorial design in culture system until death. Two-way ANOVA analysis revealed significant differences in total offspring production, percentage of pregnant females, offspring per broodstock and encysted-embryos percentage during different weeks between treatments. In each photoperiodic levels, increasing of illumination caused a decreasing trend in weekly offspring production. The highest offspring production was obtained in the females cultured in 3000 lux (at two photoperiods) in the first seven weeks (800-1400 offspring). In both photoperiods, increasing illumination causedirregular decreasing trend in the weekly average pregnant females. The interaction effects showed significant differences in the encysted-embryos percentage until the ninth weeks of culture. = The encystment percentage was higher in short photoperiod compared to longer period. In both photoperiods, the mean survival rates of females were the highest in 3000 lux (60-80%) compared to 15000 lux (28-55%) and 50000 lux (8-20%) at the first 45 days of culture. Accordingly, the treatment of 3000 lux-16:08 h was the ideal light level in the current experiments due to the highest offspring production and females’ survival rate as well as the increasing percentage of pregnant females (until six weeks), while the illumination of 50000 lux showed the lowest reproduction characteristics.

Length frequency, length-weight relationship and catch per unit of effort (CPUE) for longtail tuna and yellowfin tuna in purse seine fishing were studied in Oman Sea between July and August 2015. Length range and mean of longtail tuna were obtained 56-98 and 74.13±0.41 cm, respectively. Length range and mean of yellowfin tuna were obtained 51-128 and 74.62±0.46 cm, respectively. The length-weight relationship of longtail tuna and yellowfin tuna were calculated as W = 0.0174L2.9142 and W = 0.0655L2.7934, respectively. Totally, 802 tonnes of longtail tuna and yellowfin tuna were caught including 220 tonnes (27.43%) longtail tuna and 582 tonnes (72.57%) yellowfin tuna. Mean of CPUE (± S.E) was obtained 21.98±1.61 tonnes/setting for longtail tuna and 32.65±2.63 tonnes/setting for yellowfin tuna. Minimum and maximum CPUE of longtail tuna were calculated 7 tonnes/setting and 35 tonnes/setting, respectively. Minimum and maximum CPUE of yellowfin tuna were calculated 5 tonnes/setting and 150 tonnes/setting, respectively. Results indicated that about 31% of caught longtail tuna and 39% of caught yellowfin tuna were immature and had no opportunity to spawn. Continuation of this exploitation process can lead to recruitment overfishing of these two species.

Mercury (T-Hg), as the most toxic Trace metal, can have adverse effects on the environment. In this study, the concentrations of T-Hg were investigated in surface sediments of higher and lower tidal zones of Hormozgan province coasts including the stations of Shahr Jask, Ariyan International Wetland Lagoon, Khorgorsuzan Bandar Abbas, Bostono Industrial Zone, Coastal Park of Khumir, Shahrbonderlangeh, Bandarreqam, Bostaneh Harbor in summer 2017. T-Hg concentration was measured by Ftomic Atomic Aabsorption Spectrometry (FAAS, GTA120). From 16 stations in the higher and lower tidal zones, the stations of Khorgorsuzan Station and Azzin kinetic showed the lowest concentration of T-Hg. Based on accumulation index (Igeo), the geochemistry of the Igeo studied areas had a moderate to high contamination. Enrichment Factor (EF) showed a strong to extremely high enrichment. Regarding SQGS, all stations were higher than Effect Range Low (ERL) value. These findings raise awareness of the contamination status of surface sediments in coastal zone of Hormozgan Province, provide a valuable benchmark for future comparisons in the area, and are important for the design of appropriate policies and long-term management of those ecosystems by local managers and the national authorities.

Persian Gulf is known as an environmental resource of unique species. In the present survey, the floristic composition of marine algae of Hengam Island in Hormozgan province was investigated. Sampling was performed at four stations of the tidal zone from March 2012 to April 2014.45 marine algae species were identified in Hengam Island including23, 11 and 11 species belong to Rhodophyceae, Chlorophyceae and Phaeophyceae, respectively. The most important genus regarding to the number of species were Caulerpa˛ Ulva˛ Hypnea˛ Gracilaria and Laurencia. Our results also showed that the highest growth of green algae was in late winter and early spring. Red algae showed the highest growth in late autumn and brown algae were distributed in the whole of year.

The aim of the present study was to evaluate the effects of different levels of prebiotic on growth performance and non-specific immune parameters of zebra fish. Four hundred and twenty fish (mean weight 45 ± 0.1 mg) were supplied, randomly stocked in aquaria assigned to four treatments repeated in triplicates and fed with experimental diets contain 0, 0.5, 1 and 2% prebiotic for 8 weeks. At the end of feeding trial, growth performance and feed utilization parameters (final weight, specific growth rate and feed conversion ratio) as well as non-specific immune parameters (total immunoglobulin, total protein and alkaline phosphatase activity) were measured. The results revealed that dietary administration of prebiotic had no significant effect on growth performance (P>0.05). Also, the study of non-specific immune parameters revealed that inclusion of 0.5 and 2% prebiotic in diet remarkably increased total Ig (P<0.05). Feeding on 2% prebiotic significantly increased ALP activity (P<0.05). Regardless of inclusion level, prebiotic administration in zebrafish diet elevated total protein levels (P<0.05). According to these results it seems that inclusion of higher prebiotic levels (2%) increase non-specific immune parameters in zebra fish.

In this research Vibrio harveyi strains were isolated and identified from hepatopancreas of Litopenaeus vannamei from Tiab region, Hormozgan province. Shrimps samples were collected from five different ponds in northern and southern Tiab shrimp culture sites. Isolation phase was performed by dilution and inoculation of hepatopancreas samples on thiosulfate citrate bile salts sucrose agar medium. Purified isolates were identified phenotypically based on morphological, biochemical and physiological methods. Genomic DNA of five selected Vibrio harveyi strains were extracted and their 16S rRNA genes were amplified. Comparison of amplified 1000 bp sequence of 16srRNA genes with registered sequences in NCBI gene bank by megablast software exhibited high homology between isolated strains and Vibrio harveyi ATCC BAA-1116. Phylogenetic analysis by MEGA 6 sofware based on neighbour Joining method showed that isolated strains had similar monophyletic origin. According to these results presence of V. harveyi strains in hepatopancreas of Litopenaeus vannamei from Tiab region were genetically confirmed.

Rotifers are microscopic aquatic animals of phylum Rotifera, live in a diverse range of aquatic habitats. They are important in ecology of freshwater ecosystems by recycling nutrients and can alter trophic dynamic of planktonic communities. These features have also been used to infer environmental conditions in an aquatic habitat. Because of the important roles of this group of animals in the trophic chains of aquatic environments and the need for discovering their biodiversity, this study was planned to analyze the patterns of rotifer community structure in response to temporal fluctuations in environmental variables in two water bodies in northwest Iran. Samples were collected seasonally between October 2014 and November 2015. Temperature, pH, DO, conductivity, salinity and rotifer abundance were measured. In total, 28 rotifer species belong to 10 families of phylum Rotifera were identified. Canonical correspondence analysis (CCA) was used to estimate the relationship between environmental variables and biodiversity of rotifer taxa. The clusters showed strong correlation with dissolved oxygen and electrical conductivity for shaping the rotifer assemblages in both reservoirs.

In this study, trophic interactions were studied among three elasmobranches including Iago omanensis, Rhinobatos punctifer and Torpedo sinuspersici coexisting in the depth ranging from 50 to 100 meters in the Oman Sea (Sistan and Balochistan waters). A total of 238 specimens were collected using industrial bottom trawlers of ‘FERDOWS’ during spring and summer,2014 and their stomach contents were analyzed based on VI, FO, %IRI indices and nMDS analysis. Results showed that I. omanensis fed mainly on teleosts, and crustacean and cephalopod were found in the several stomachs. Moreover, T. sinuspersici had specialized diets on teleosts. On the other hand, R. punctifer had a specialized diet on crustacean. An analysis of similarity showed significant differences among three studied species (R=0.574; P=0.001). Analysis of pair-wise tests detected the greatest dietary differences between R. punctifer and T. sinuspersici, while I. omanensis and T. sinuspersici showed the lowest differences. The results showed that there is resource partitioning, which can be related to morphology and feeding behavior of each species.

In this study, the effects of fish liquid fertilizer (Fish Hydrosylate) and aqueous extract of green-algae (chactomopha gracilis), from cladophorales order were evaluated on growth properties of tomato. The fish liquid fertilizer obtained from Persian Gulf fish waste contained P2O5 (0.48 %), K2O (0.14 %), Fe (30.60 ppm), Zn (20.50 ppm), and N (2%). The variance analysis of the traits including shoot length, shoot diameter, radicle length, leaf width and chlorophyll content revealed a significant difference among treatments (p<0.01). The mean comparisons of traits using Duncan's multi-domain test indicated that the fish liquid fertilizer treatments with concentrations of 0.001 and 0.0001 had the highest effects on entire traits. The green-algae extract treatments showed positive effects on studied traits and improved tomato performance and growth parameters. Although, the effects of green macroalgae extract (chactomophora gracilis) were less than that those of fish liquid fertilizer.

This study aimed to investigatethe changes in Gonad Somatic Index (GSI), vitellogenin induction and ovarian histopathology in zebrafish (Danio rerio) adult female, as an ecological model in toxicology, after exposure to 0.002, 0.02, 0.2, 2 and 20 µg/L cadmium chloride for 21 days under sub-lethal condition. The results showed that 0.002 to 20 µg/L cadmium chloride had no significant effect on the survival, But GSI and vitellogenin concentrations in whole body homogenate (WBH) decreased in a dose- dependent manner in all treatments. Gonad histology showed increased proportion of atretic follicles, reduced proportion of vitellogenic oocytes, haemorrhage, hyperemia, membrane folding in some oocytes, hypertrophy of granulosa cells, proteinaceous fluid and decreased yolk formation in vitellogenic oocytes. These changes indicate a disturbed reproductive output. The results of this study showed that an increase in atretic follicles and decreased vitellogenin have negative effects on zebrafish fertility. Moreover,continuous exposure to subacute sublethal concentrations of cadmium chloride had anti-estrogenic and irreversible effects on zebrafish reproduction.

The cultivation techniques of dinoflagellates is often problematic due to their sensitivity to hydrodynamic (shear) stress. For this study, sea anemone was collected from the east coast of Hormuz Island. First, we extracted symbiotic dinoflagellate, Symbiodinium sp. from Stichodactylla haddoni using manually homogenization. After transferring to the laboratory, samples were cultured in different mediums of ASP12, ASP8, F2-Gillard and L1, under temperatures of 17±1, 23±1 and 29±1 °C. The amount of light was about 100 µ mol.photon.m-2.s-1. Then, microalgae were cultured again in the selective medium ASP12. Cell counting was performed using a Neubauer chamber every day. Growth and mitotic index were measured during the period of cultivation. Maximum mitotic index, cell numbers and growth rates were observed at 23±1 °C at a rate of 40%, 12×105 cell/ml and 0.086 d-1,respectively. The results showed significant differences between cell numbers and growth rates of Zooxanthellae at three different temperatures (P <0.05). In conclusion, this study showed that environmental factors such as temperature can affect the growth rate of dinoflagellate, Symbiodinium sp.

This research evaluated the effects of dietary supplementation of commercial Bactocell and D-Pro probiotics on growth performance, survival and carcass composition in giant freshwater prawn Marcrobrachium rosenbergii postlarvae (PL) in a 60 day feeding trial. A total of 600 PLs with mean initial weight of 0.090± 0.004 g were assigned to five treatments each with three replicates in a completely randomized design experiment with 40 PL in each 50 L tank. . Experimental groups including control diet (without probiotic), 0.3 g Bactocell (treatment 1), 0.6 g Bactocell (treatment 2), 0.4 g D-Pro (treatment 3) and 0.8 g D-Pro per kg diet (treatment 4). After feeding trial, growth indices, dietary factors and proximate compositions were analyzed. The results showed that final weight, weight gain, condition factor, survival, specific growth rate and protein efficiency ratio were significantly higher in prawns fed with probiotics compared to control (p<0.05). The highest level of growth parameters and the lowest level of feed conversion ratio were observed in treatment 4. Proximate composition was significantly different among treatments. The highest levels of protein and lipid were observed in treatment 4. According to the results, the application of diets supplemented with Bactocell and D-Pro probiotics can promote growth and dietary factors and proximate composition in cultured giant fresh water prawn PLs.

This study aimed to investigate macroinvertebrates biodiversity indices in Chalus River in Mazandaran province and the impact of spring floods on these indices during spring and summer in 2015. Environmental parameters including daily discharge data during 2014-2015, temperature, dissolved oxygen, nitrate, phosphate, pH, TDS and EC were measured in river branches and main channel of the river at nine stations. Benthic macroinvertebrates were collected by surber sampler at each station, then identified and counted. Results showed significant differences in biological indices of EPT, EPT/Chironomidae, ASPT, HFBI, Shannon-Wiener and Simpson diversity between two seasons (p<0.05). Among environmental parameters, the discharge level showed the most negative correlation with biological indices (p<0.05). Furthermore, the amount of nitrate and phosphate indicated the most positive and significant correlation with indices. Based on RDA results, parameters including temperature, oxygen, nitrate and pH in spring, and discharge level in summer were the most important affecting factors. Results of the present research showed that the spring floods affect directly or indirectly on environmental parameters such as DO and pH that can consequently have influence on biological indices of benthic macroinvertebrate in Chalus River. Generally, steady changes in temperature, precipitation, and stream hydrology affect stream biota, but such effects may be less important compared to the impact of flood events.

This study investigated the fish species inhabiting hot springs of Hormozgan province including Geno, Khoorgoo, Sargez Khoorgoo, Siahkosh and Pahash . According to previous studies and the present study, the Aphanius ginaonis was the unique species in Geno hot spring. Fingerlings and mature females of A. ginaonis were remarkably found in the spring in August. While, previous studies reported the the breeding season for this species in July. Therefore, it is likely that A. ginaonis reproduce throughout the summer. On the other hand A. dispar was found as the unique species in Khoorgoo and Pahash springs. Moreover, a worm form arthropod larvae was recognized in the gill of Khoorgoo Aphanius. In addition, a remarkable number of A. dispar larvae were observed in August, showing that the reproduction seaoson of this species in the pahash spring is in August. In Sargez Khoorgoo spring, A. dispar with mature ovaries were found in March. We observed Aphanius sp. and two varieties of Iranian cichlid Iranocichla hormuzensis species that were clearly different in two water sources.

Increasing in water ammonia is one of the major problems in aquaculture. Nitrogen-containing materials are producing in different ways, including oxidation of nitrogen-containing organic matters such as proteins, manure decomposition and ammonia excretion by fish. The increase in these compounds in water recirculation systems and aquaria has always been considered as a stress-causing factor. On the other hand, either increasing and/or decreasing in ::union::ized ammonia are affected by pH changes. In order to obtain the LC50 of ammonia, zebrafish were exposed to seven treatments including control, 0.069, 0.138, 0.276, 0.552, 1.105 and 2.210 mg/L of ::union::ized ammonia. Then, in order to obtain a tolerable pH range fish were exposed to either gradual increase or decrease of pH (0.1 units per minute) using HCl and NaOH 0.4 N. The amount of LC50 for different time periods was determined using the probit software. The amounts of LC50 for 24, 48, 72 and 96 hours were 0.766, 0.634, 0.532 and 0.471 mg/L, respectively. Maximum and minimum average of pH tolerance threshold was 11.64±0.04 and 2.60±0.09 respectively. The results showed that zebrafish is a sensitive species to ammonia poisoning, but it is resistant to pH changes.