Iranian Journal of Fisheries Sciences
Volume:21 Issue: 2, Mar 2022

Acute toxicity and effects of sublethal concentrations of oxadiargyl herbicide (3% EC) were examined on DNA damage (Comet assay) and histopathological changes in common carp (Cyprinus carpio) fingerlings with average weight and length of 19.15±1.05 g and 10.09±0.47 cm, respectively. The fish were exposed to 0.1, 0.3 and 0.5 mg/L of the herbicide for 30 days. Estimated 96-h LC50 value for oxadiargyl in common carp was 0.6 mg/L. Histopathologically, no change occurred in different tissues of the control group, while marked lesions were induced in vital organs of fish that their severity was increased with enhancement of the herbicide concentration. Sublethal exposure to different concentrations of oxadiargyl induced: hyperplasia of lamellar epithelium, hyperemia, inflammatory cells infiltration, aneurysm and rod-like structures of secondary lamellae in gill tissues, as well as change in size and number of melanomacrophage centers in kidney and spleen tissues. Necrosis of tubular epithelium, hyperemia, and protein casts were also observed in kidney tissue. Focal necrosis, fragmentation, vaculization and shrinkage of myofibrils, and eosinophilic cytoplasm were observed in muscle tissues of exposed fish. Erythrocyte cells of fish exposed to sublethal concentrations of 0.1, 0.3 and 0.5 mg/L, showed 18.3%, 19.1%, and 31.5% tailed DNA, respectively, significantly higher than the control group (p<0.05). Moreover, exposure to oxadiargyl significantly decreased WBC, RBC, Hb, Hct compared with the control group (p<0.05). In conclusion, these results revealed that oxadiargyl is highly toxic to common carp with genotoxic and hematotoxic effects, as well as adverse effects on histopathology of vital organs.

In the present study, the ballast waters from 24 ships arriving at Shahid Rajaee Port in Bandar Abbas, Hormozgan Province, Iran, were studied in two warm and cold seasons (summer 2017 and winter 2018). The zooplankton sampling was conducted under the MEPC 173(58) method, by bucket and using a 50-micron mesh to filter 300 liters of ballast water. In total, 57 zooplankton species, belonging to 8 phyla, 11 classes, 15 orders, and 35 families were identified in the sampled ballast water, among which the Arthropoda phylum with 16 families and 23 species recorded the highest number of species  The highest and lowest density among the studied samples belonged to the Tintinnopsis gracilis species from the Codonellidae family (11.4%) and Calanopia elliptic species from the Pontellida family (0.04%), respectively. The results of the Pearson correlation test showed that there was a negative correlation between the measured pH parameter and the frequency of zooplankton (p<0.01). There was also a positive correlation between EC and Shannon diversity index (p<0.05). PCA test results showed that EC, temperature, salinity, and TDS factors had the most impact in stations with the highest number of species and abundance of zooplankton. The results of the cluster diagram showed the highest similarity between winter at the Western Indian Ocean (WW) and summer at the Western Indian Ocean (WS) at the level of 54%, and the lowest similarity between the winters at the Northwestern Indian Ocean (NW) at the level of 24% with other regions. All the studies species in the ballast waters of the Persian Gulf had been identified and reported by previous studies but certainly requires continuous monitoring management of the ballast water, and supervising their discharge into the marine environment.

The present study aimed to analyze the concentration of aromatic hydrocarbon transfer cyclic through consumption of Binni fish (Mesopotamichthys sharpeyi) at Huralazim wetland and estimates the risk of consumption at 7 stations of Huralazim wetland in spring 2018 (one season). A statistic populations included sediment (n=21), water (n=21) and fish (n=21). The concentration of aromatic hydrocarbons ranged from 178.45 to 1386.26 mg/ kg. Acenaphthene and Pyrenees had the highest concentration of hydrocarbon compounds in sediments. In water samples of 7 stations, the concentration of aromatic hydrocarbons ranged from 17.12 to 651.79 mg/ L, and Acenaphthene and Naphthylene with the mean concentrations of 42 and 28.83 mg/L, respectively, which were the most abundant aromatic compounds (p<0.05). The results indicate the highest and lowest concentrations of total aromatic hydrocarbons in fish caught at station 7 (43±2 mg/kg) and station 1 (9.52±3.06 mg/kg), respectively. The highest carcinogenesis rate (1.13) and mutation rate (23.49) were found at stations 7 and station 5, respectively. The gradual carcinogenesis rate of Benz [a] pyrene ranged from 0.00003 to 0.0029, and its mean rate in Huralazim wetland reached 0.0027. The gradual mutation risk assessment for Benz [a] pyrene was estimated to be 0.055 (which ranges from 0.034 to 0.061). Most of the hydrocarbon compounds in the sediments have originated from pyrolytic and fossil fuels. According to mutant and carcinogenic standards, the daily consumption of fish in this wetland increases the risk of cancer and mutation incidences. Measures should be taken to reduce the consumption of fish at risk in Huralazim wetland, thus minimizing the risk of gradual cancer or mutation.

In the present study relationship between shrimp catch per unit effort (CPUE) and satellite-based environmental parameters, chlorophyll-a (Chl-a) and sea surface temperature (SST), was investigated in 27 stations in Bushehr provincial waters in the geographical position from E 50˚ 44´ and N 28˚ 59´ to E 51˚ 40´ and N 27˚ 33´, in July 2017 and July 2018. SST and Chl-a data were extracted from +ETM Landsat 7 sensor and Modis Aqua (EOS PM) satellites images. Four research surveys were conducted using a traditional vessel to record local physico-chemical parameters of water and estimate shrimp catch per unit effort (CPUE) in studied stations.The results of linear regression analysis and correlation coefficient showed a negative and strong relationship between SST- Chl-a overlap value and shrimp CPUE in waters of Bushehr province (r = -0.84), while weak negative and positive relationships were observed between SST and chlorophyll-a with shrimp CPUE with r = -0.34 and 0.03, respectively.

Lactobacillus brevis was isolated from the intestinal tract of Sander lucioperca and its immunological parameters as well as intestinal morphology were studied. Thereafter, the fish were challenged with 4.5×108 CFU/g Aeromonas hydrophila. The fish were monitored daily and the rate of survival was recorded over a period of 7 days post-challenge. The results showed that feeding with supplemented L. brevis (108 to 1010 CFU/g) had significant effect (p<0.05) on the survival rate. The serum lysozyme, alternative complement activity (ACH50) and IgM was significantly enhanced by dietary probiotics during the feeding period and post challenge compared to the control group. The serum IgM levels of dietary supplementation of L. brevis were significantly higher than that of the control after 8 weeks (p<0.05). After 60 days total bacteria and probiotics in the intestinal tract in groups fed with doses of 108 to 1010 CFU/g L. brevis had increased ratio in compare with control sampels. The survival rates after dietary administration of probiotics were significantly higher than that in control in post challenge. The probiotic (1010 CFU g-1) can be used as an effective bio-control agent and as an immune stimulant in aquaculture.

Shark cartilage is considered as a natural dietary supplement consisting of anti-angiogenic, immunostimulatory, and anti-inflammatory characteristics. Therefore, this study was designed to inspect the possibility that whitecheek shark (Carcharhinus dussumieri) cartilage proteins motivate expression of NKG2D, CXCR3, NKP46, and NKP44 receptors on natural killer cells and their activities against SW742 cell line. To this end, cartilaginous areas of whitecheek shark were caught, minced, stored at −20°C and then lyophilized and kept in refrigerator. Peripheral blood samples were collected from healthy people and a number of 106 cells were considered for cell viability using trypan blue method. Activation of NK cells was determined using 106 cells stimulated following exposure to 0.2 and 3 mg mL-1 extracted shark cartilage proteins in 4, 8, and 18 h incubation. The results showed that cytotoxicity of NK cells increased significantly by elevating the concentration of extracted proteins at incubation period of 24 h (p˂0.05). The findings demonstrated that NK activity elevated markedly by increasing the concentration and volume of protein suspension and the exposure time (p˂0.05). Interestingly, the expression of NKG2D, CXCR3, NKP44, and NKP46 receptors was not significant in any transcription level by exposing to 0, 25, and 75 µg mL-1 in 4, 8, and 18 h incubation period (p˃0.05). Together, extracted shark cartilage protein could motivate the immune system capabilities through using NK cells against cancer tissues but specific receptors on T cells cannot be activated by these bioactive materials.

This study was conducted in order to compare the hornwort aquatic plant (Ceratophyllum demersum) with an artificial filter for purification in a recirculating aquaculture system (RAS). At first, the fluctuation of nitrogen components of the water reuse system equipped with artificial filtration was evaluated. Experiments were performed during three months. The hornwort aquatic plant was collected from Siadarvishan River and brought to the breeding and rearing system (JANAT Agriculture high school-Rasht). Subsequently, the plants were kept in river water for one month for adaptation. Initially, the plant wet biomass was weighted. For this purpose, 600 fishe specimens from the Cichlidae family (Oscar, Anjel, Burli and Zebra) provided from a local market were distributed between 12 aquarium tanks (160-liter capacity) in triplicate groups. Nitrogen component of water, such as ammonia (NH3), nitrite (NO2-) and nitrate (No3) were measured. Growth parameters and survival rate of fishe specimens at the end of the trial were evaluated. The results of this experiment indicated that nitrogen component when using hornwort aquatic plant as a biofilter not show better performance than the artificial filter treatment. The growth parameters performances when using the aquatic plant as biofilter in comparison with artificial filter declined.

Coastal waters in northern part of Hormuz Strait receive large inputs of anthropogenic pollutants. This study was conducted to determine the effects of environmental contaminants on plasma enzymes, thyroid hormones and biochemical blood parameters of Periophthalmus argentilineatus to monitor marine pollution from northern part of Hormuz strait. For this purpose, a total of 90 specimens were collected from three estuarine stations (30 specimens for each station) including Shour-e-aval (first station; St1), Souro (second station; St2) and Bustanoo (third station; St3) and some blood plasma indices, such as aspartate aminotransaminase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), glucose (GLU), cholesterol (CHOL), triglyceride (TRIG), and thyroid hormones including triiodothyronine (T3), thyroxine (T4) and thyroid-stimulating hormone (TSH) were measured. Results showed that the plasma enzymes levels were significantly higher in fish from the polluted location (Bustanoo; station 3). Concentrations of thyroid hormones and also the glucose and cholesterol levels were significantly higher in the samples from the station 3 (p<0.05). Due to the negative impact of pollutants on biochemical and hormonal functions of blood serum of resident species, including P. argentilineatus, this species can be used as a bioindicator of pollution in northern part of Hormuz Strait.

The study evaluated to model the growth and reproduction aspects of the hake, Merluccius merluccius, in the Sea of Marmara. On-board sampling was conducted on the commercial beam trawl fishery from February 2016 to January 2017. For the growth trajectories, using monthly length frequency data set, different methods were employed to improve parameter optimization. The variation of reproductive intensity was modelled using Generalized Additive Models (GAMs). The growth was fast and parameterized as L∞=65.9 cm, K=0.16 year-1 according to the Electronic Length Frequency Analysis (ELEFAN) with genetic algorithm optimization approach. Seasonal variation in growth, fitted a seasonally oscillating VBGF (soVBGF), indicated intense seasonality. The onset of the positive phase of the growth oscillation was observed around October proofed by a high fish condition that the growth starts accelerate after the summer period. A high gonadosomatic index (GSI) was evident over most of the year except between May and July, captured also the time component in the GAM modeling. The total length and fish condition have the highest impact on the GSI among the modeling parameters evaluated while temperature has low partial effect. The length at the first sexual maturity for females and males was calculated at 26.5 and 22.0 cm, respectively, lower than that of the Atlantic and Mediterranean waters. It is believed that this study allows deeper and new conclusions for the management of hake stock in the Sea of Marmara and Mediterranean Basin.

Investigating the relations and mechanisms of coexistence among sympatric species is essential to comprehend their ecological roles in the food webs. In the present study, the diet and trophic interactions of 5 abundant teleost species coexisting in the northern Oman Sea were examined using stomach contents analyses. The cumulative prey curves showed that the sample size of each studied species was large enough to clarify the general dietary preferences. The vacuity indices of Netuma thalassina, Plicofollis dussumieri and Otolithes ruber were less than 50%, indicating the comparatively gluttonous behavior of these species, while the estimated vacuity indices of Lutjanus johnii and Carangoides malabaricus were more than 50%. Assessment of %IRI (index of relative importance) revealed that diets of N. thalassina, O. ruber and C. malabaricus were similar and consisted mostly of teleost fishes followed by crustaceans. Conversely, P dussumieri and L. johnii mostly fed on crustaceans followed by teleost fishes. Results showed that P. dussumieri and L. johnii occupied an intermediate trophic level, whereas N. thalassina, O. ruber and C. malabaricus occupied high trophic levels, placing them as top predators in the food web. In total, analyses indicated that there were no significant differences in diets between these 5 teleost species.

In the present study, 7% silver-low-density thin polyethylene films were successfully prepared through the melt mixing method. These films were applied to reduce the harmful antibacterial properties of Huso huso fillets at refrigeration temperatures, thus extending their shelf life. The total viable bacteria count for H. huso fillets wrapped in a 7% Ag/LDPE nanocomposite was 3.04±2.43 (log CFU/g) in 10-2-diluted fish samples, which is significantly lower than those of the control and the LDPE group after two days of cold storage. The lowest psychrophilic bacteria count (log CFU/g) was recorded for the 10-2-diluted fish samples encased in Ag/LDPE-NC in which Staphylococcus aureus count (SAC) reached 1.3±1.40 log CFU/g on days 2 and 4 at 10-2 dilution, respectively. It was extraordinarily going up and reached 6.97±3.91 log CFU/g for group Ag/LDPE showing high effectiveness of Ag/LDPE on retarding the SAC sampled from the caviar fish fillets up to the fourth day. It is concluded that application of 7% Ag/LDPE film produced by the melt mixing method can remarkably retard growth of bacteria on fresh H. huso fillets. Thereupon, the total viable bacterial count and psychrophilic bacteria growth and S. aureus activity were significantly mitigated up to four days of preservation at the refrigerator at which the values were below acceptable limits for fresh fish.

The aim of this study was to evaluate the efficiency of polyurethane foam containing silver nanoparticles synthesized by Verbena officinalis leaf extract in controlling of Yersinia ruckeri in treatment of water tanks of rainbow trout farming. Biosynthesis of silver nanoparticles is done with 2mM silver nitrate solution and Verbena officinalis extract. To study antibacterial effects of the produced foams in vitro methods were used, including antibiogram tests on a petri dish, the diameter of inhibition and tube test at different times. Also In vivo methods were used consisting of treatment of water contaminated with bacteria in the presence and absence of fish. Results of mean of diameter of inhibition zone of foam containing 50 and 100mg of Ag-NPs on Yersinia ruckeri were 15.33±1.6 and 14.83 ±0.76mm respectively. Yersinia ruckeri was completely removed after 2h contact with foams of 50 and 100 mg Ag-NPs in water treatment without fish, and after 10min in test tubes at different times. Antibiogram tests showed no colonies in 50 and 100mg Ag-NPs at the bottom of the foam. Water treatment in the presence of fish showed a significant reduction in density of bacteria after 48h contact with filters containing 50 and 100mg silver nanoparticles. Results of this study, as a new production of nano-biofilter, can be used to reduce and control Yersinia ruckeri bacteria in rainbow trout fish farms.

The population parameters of Malabar trevally (Carangoides malabaricus) were studied in the Persian Gulf and Oman Sea from December 2016 to November 2017. 1030 specimens were collected. The fork length ranged from 14 to 34 cm, with average 25.60±3.52 cm. The total weight ranged from 60.4 to 534.5 g, with average 329.03±113.46 g. The asymptotic length (L∞) and growth coefficient (K) were 37 cm and K=0.85 per year, respectively. The probability of capture was calculated in fork length as L25%=22.47 cm, L50%=24.02 cm and L75%=25.26 cm. The length-weight relationship was determined as W= 0.06 L 2.62. The annual total mortality (Z), fishing mortality (F), and natural mortality (M) coefficients were estimated 3.1, 1.62, and 1.48 per year, respectively. The current rate of exploitation (E) was 0.52, and the value of exploitation ratio was found reasonable for current fishing effort. The results indicated that the Malabar trevally stock was not overexploited.

This study aimed to investigate the effect of sea cucumber methanol extract on Vibrio harveyi and also to investigate the measurement of changes of factors in farmed shrimp, Penaeus vannamei. Holothuria parva with an average length of 15-10 cm were collected from tidal coasts of Dayyer city, Bushehr province. Different concentrations of H. parva extract (50, 100, and 150 µg/mL) were used to prepare the food of the experiment. Vibrio harveyi bacterial strain (PTCC: 1755) was obtained from the Collection Center of Industrial Microorganisms of Iran. Thousand shrimp with an average weight of 10±1 g were collected from culture ponds and distributed among 15 aquariums containing 100 liters of water with a salinity of 40 ppt. The mean comparison of survival rates showed that there was no significant difference among treatments on the first day (p>0.05). Also, there was significant difference among survival rates in other treatments with negative and positive control treatments (p<0.05). The results also showed that there was significant difference among the groups in PO (phenol oxidase), POD (peroxidase), THC (total haemocyte count), TPP (total plasma protein), and SOD (superoxide dismutase) with the amounts of negative and positive control treatments during the experimental days (p<0.05). The highest amounts of measured factors were 538.18±14.45 U min-1 mL-1 (Treatment 3) for PO on the fifth day, 7.19±0.3 nmol min-1 mL-1 (Treatment 2) for POD on the fifth day, 37.98±6.49×105 cell mL-1 (Treatment 3) for THC on the third day, 93.67±14.8 mg mL-1 (Treatment 3) for TPP on the third day, and 1663.21±37.07 activity U mL-1 (Treatment 3) for SOD on the third day. According to the results, survival was directly related to the concentration of methanolic extract. The highest increase in safety factors was observed in treatment 3, with concentration of 150 µg / mL methanolic extract of sea cucumber.

Metals are the major pollutants in aquatic environment. A lot of research literature is available globally about accumulation of heavy metals in aquatic ecosystems as well as in different body organs of aquatic animals, especially fish. Heavy metals mainly generate reactive oxygen species (ROS) in aquatic animals that lead to oxidative stress production. ROS cause oxidative damage to different animal tissues and cellular components, like protein and DNA. Aluminum exists in aquatic environments of Pakistan in concentration higher than permissible limits. So, the present study is conducted to determine toxic effects of aluminum on DNA in peripheral blood erythrocytes of fish viz., Cirrhinus mrigala and Ctenopharyngodon idella. For this purpose, fingerlings of each species were exposed to four sublethal concentrations of 17, 25, 33 and 50%. The effects of aluminum on 96-h LC50 concentrations were evaluated for a period of 30 days under controlled laboratory conditions. Results revealed significant toxic effect of this metal on genetic material of fish. Among the four treatments, 50% sublethal concentration 96-h LC50 of aluminum caused significantly higher percentage of DNA damage, genetic damage index and cumulative tail length of comets. Highest frequency of micronuclei was observed in 50% treatments of 96-hr LC50 exposure of aluminum which was not statistically (p<0.05) similar to micronuclei frequency caused by 33% of 96-hr LC50 of aluminum in fish. The findings of this experiment showed that aluminum exposure caused genetic damage in fish. Moreover, comet assay and micronucleus test appeared to be reliable indicators of metallic ion toxicity in aquatic animals.

Acid-soluble collagen could be isolated from fish skin using acetic acid. In recent years, much attention has been paid to collagen from marine sources, mainly arising from the fact that there is no risk of contagious diseases. Moreover, by processing the fish, significant amounts of waste materials are produced which can be considered as a substitute for these collagen sources. Thunnus tonggol skin collagen was extracted by acid and base methods and evaluated by SDS-PAGE, FTIR and UV spectrophotometry and amino acid composition analysis. To determine biocompatibility, growth, and proliferation of extracted collagen, MTT and H&E staining methods were used. The results, predicated on SDS-PAGE and amino acid analysis, demonstrated that the fish skin collagen was of type I consisting of two α chains (α1 and α2) with molecular weight of 135 kDa and mass fraction of β. FTIR analysis also revealed helical compositions of both collagens, and UV spectrophotometry in T. tonggol skin collagen indicated a maximum absorption of 235 nm. The amount of collagen extracted from T. tonggol skin turned out to be 17.3% dry weight. Analysis of extracted collagen amino acids from the mentioned fish showed that glycine was the predominant amino acid. Human fibroblast culture presented a superior growth and good biocompatibility on extracted collagen. So, this type of collagen could be used in tissue engineering as a proper scaffold.

Phytohormones are present in seaweeds but little is known about occurrence and content of them in seaweeds of Persian Gulf. The aim of this study was extraction of abscisic acid and gibberellin in Sargassum muticum and Gracilaria corticata. The seaweeds were collected bimonthly over one year at Bushehr coasts, Persian Gulf, during a range of environmental conditions. We explored new HPLC method for extracting abscisic acid and gibberellin from the seaweeds. It was found that the lowest amount of abscisic acid in Sargassum and Gracilaria were 0% in several months and the highest were 20.667 and 66.20% in November, respectively. Maximum yield of gibberellin in Sargassum and Gracilaria occurred in July (58.561%) and May (84.467%), respectively. The highest Sargassum biomass obtained in January (679 g/m2) and maximum biomass of Gracilaria was in March (423.33 g/m2). The results showed that biomass of two algae had negative correlation with abscisic acid and positive with salinity. This is due to inhibitory effect of abscisic acid on growth. There was no significant correlation between gibberellin and biomass of the two algae. In this article we showed that phytohormones existing in seaweeds of Persian Gulf could be used in algae liquid fertilizer.

A study was conducted to determine the growth performance and bioaccumulation and tolerance of metal mixture toxins in five fish species including Labeo rohita, Catla catla, Cirrhina mrigala, Hypophthalmichthys molitrix and Ctenopharyngodon idella separately, under chronic exposure of metal mixture (Fe + Zn + Pb) at sub-lethal concentrations (1/3 of LC50) for 12 weeks period. Moreover, response of different body organs of fish towards bioaccumulation of metals under metals mixture stress was also determined. It was found that the relationships among growth parameters of metals mixture stressed as well as unstressed (control) fish were significantly different. Results showed that, the sub-lethal exposure of metals mixture induced substantial impacts on the wet weight gain (g) and length (mm) of fish species, with following trend; C. catla> C. idella> C. mrigala> L. rohita >H. molitrix. However, growth rate of fish under control treatment (no stress) was significantly higher compared to the fish exposed to metals mixture. It was also observed that the condition factor was positively correlated with fish growth and expressed the extent of fish well-beings. The bioaccumulation pattern in the body organs was observed with the following trend: liver> kidney> gills> skin> fins > muscles> bones. This study concluded that metal mixtures seriously affect the growth and development of aquatic organisms.

This study was aimed to determine the effect of a freezing extender developed for Mesopotamian spiny eel (Mastacembelus mastacembelus Banks & Solander, 1794). Mesopotamian spiny eel was caught from May to July 2017 in the Atatürk Dam Lake and Euphrates Basin (meridians) in Şanliurfa, Turkey. During the study, the animals (n=10; 8 males, 2 females) were caught with gill nets (22 mm×22 mm, mesh size) and kept under natural lake water [temperature (22.00–23.60ºC), oxygen (8.45–8.98 mg/l), pH (8.14–8.50) and salinity (0.22 ppt)]. Semen was collected from eight males (406.46±166.68 g) weekly by abdominal massage after the hormonal injections of human chorionic gonadotropin treatment. Sexual maturation and spermiation of MSE males (n=8) were stimulated by weekly injections of human Chorionic Gonadotropin (hCG; Pregnyl, Merck Sharp Dohme, Turkey) [(1 International Unit (IU) hCG/body weight (g)/week]. At the 7th week of hormonal treatment, milt from eight mature males was carefully collected by abdominal massage, avoiding contamination with urine and feces into the petri dish, 24 h after the hormone applications. The motility of the collected spermatozoa and the spermatozoa density were evaluated on day of collection. Sixteen milliliter pooled ejaculate (2 milliliter per male) was split into two equal aliquots and diluted with the ArŞaDo extender (NaCl (163mM), NaHCO3 (9.4mM), MgCl2 (0.84mM), CaCl2 (8.26mM) and KCl2 (18.16 mM)) and the P1 (NaCl (125 mM), NaHCO3 (20 mM), MgCl2 (2.5 mM), CaCl2 (1 mM) and KCl2 (30 mM)) extenders. After two weeks, straws were thawed in a water bath at 40°C for 13 s and post-thaw sperm motility was immediately estimated subjectively. For the activation, saline solution (0.9% NaCl) was used. Sperm motility of thawing samples was significantly higher in ArŞaDo extender than in P1 extender (42.66±1.17% vs. 32.96±1.27%, respectively). The fertilization rate in ArŞaDo extender was higher than sperms preserved in the P1 extender (82.03±1.94% vs. 73.43±1.45%, respectively). In conclusion, the ArŞaDo extender improved the post-thawing spermatozoa motility percentage and fertilization rate in Mesopotamian spiny eel males.

The dactylopterid fishes are non-commercial fishes and occasionally caught as a by-catch during commercial trawling. Two specimens of Dactyloptena peterseni were collected during the survey of commercial trawl catch at Karachi fish harbor. This is the first report on the occurrence of Dactyloptena peterseni in the Pakistani waters. The present study gives the detail description of morphometric and meristic characters of D. peterseni. The D. peterseni is characterized by possessing a single, isolated, elongate spine anterior to continuous spinous dorsal fin. The present specimen showed resemblance with the specimens described from other parts except in having 6 rays in ventral fins.