Iranian Journal of Ichthyology
Volume:1 Issue: 1, Mar 2014

Fifty-four specimens of the kingsoldier bream, Argyrops spinifer (Forsskal, 1775) from coastal waters of the Persian Gulf, in Bushehr Province, were aged by otolith readings to assess the suitability of using otolith length/weight for age estimation in this fish. Otolith length and weight increased along with an increase in length and age of the fish. The relationship between fish length (TL) and otolith weight (OW) was as OW=0.007TL–0.79 (r2=0.90), between fish age (t) and otolith length (OL) as OL=5.576 (t)0.346 (r2=0.88), between fish age (t) and otolith weight (OW) as OW=0.03 (t)0.837 (r2=0.91) and between fish length (TL) and otolith length (OL) as OL=1.125 (TL)0.644 (r2=0.92). Thus, these parameters could be readily used in age determination of A. spinifer. The proportion of average otolith weight to fish total length which partly shows the growth rate, was assessed as 0.005.

Eurasian perch, Perca fluviatilis L., is one of the most important species in European freshwater aquaculture and probably one of most important of cold freshwater species in nearest future. The aim of this study was to test the Ovaprim in artificial reproduction in Eurasian perch in two temperatures (12 and 14°C) with using new oocyte maturation stage system. The results obtained in present study showed that the oocyte maturity stage is very important in artificial reproduction of perch. The spawning effectiveness, in present study described as ovulation rate, latency time and embryo survival to the eyed-egg-stage, was higher when fish with higher oocyte maturity stage was used for reproduction. The latency time was depended on oocyte maturity stage and on water temperature. If the water temperature was highest from tested (14°C) and oocyte maturity stage was also the highest (4th) the latency time was the shortest. The obtained results showed that Ovaprim might be successfully applied in artificial reproduction of Eurasian perch under controlled conditions.

The Lernaea parasite was reported in Alburnus hohenackeri Kessler, 1870, collected from the Char-Nimeh (or Chahnimeh) lake, Eastern Iran. Three fishes were infected with L. intestinalis having 3 to 22 parasites increasing with fish size. The maximum and minimum of parasite lengths were 138.02 mm and 24.54 mm respectively. The prevalence, mean intensity and abundance of infection by plerocercoid of L. intestinalis were 33.33%, 13.33, and 4.44 respectively.

To investigate the effects of different hormonal treatments on the oocyte maturation in wild- caught grey mullet (Mugil cephalus), fish were subjected to 4 different hormonal treatments as follows: (a) a control group received 0.5 ml/kg B.W. physiological saline, (b) fish injected with 20 mg/kg carp pituitary extract (CPE) as a priming dose followed by 200 µg/kg sGnRHa as resolving dose, (c) fish injected with 200 µg/kg sGnRHa as a priming dose followed by the same injection as a resolving dose and, (d) fish received 20 mg/kg CPE as a priming dose followed by injection of 200 µg/kg sGnRHa in Freund’s incomplete adjuvant emulsion. All GnRHa treated groups received 20 mg/kg B.W. metoclopramide as dopamine antagonist (DA). The interval between two injections was 24 hrs. At 6, 12, 24 and 48 hours post final injection ovarian samples were taken by soft plastic catheter and the maturation of oocytes was examined according to oocyte diameter, position of germinal vesicle and coalescence of oil droplets. The results showed that all hormonal treatments were significantly effective in progression of the oocyte maturation in comparison to control group. The treatments (b) and (d) were more effective than treatment (c) and resulted in final oocyte maturation and germinal break down. It was for the first time that emulsified GnRHa (sGnRHa-FIA) was shown to be effective in final oocyte maturation and ovulation of the species. The results showed that all hormonal treatments were effective in induction of oocyte maturation in wild-caught grey mullet and could be used in commercial hatcheries.

The distribution of yellowfin seabream populations in estuaries and inland rivers in coastal area of the Persian Gulf and Strait of Hormuz is presented. Based on morphological and mersitic characteristics and also color pattern, these populations are assigned to the recently described sparid fish, Acanthopagrus arabicus Iwatsuki, 2013 which is distinguished by pelvic and anal fins vivid or strong yellow; black streaks proximally on inter-radial membranes between yellow anal-fin rays absent; lower caudal-fin lobe yellow; clear black blotches usually absent just beneath inter-radial membranes between dorsal-fin rays but upper dorsal-fin membrane often with darker margin; weak diffuse dark blotch at origin of lateral line, usually covering first pored lateral-line scale, continuing as a dense dark shading over upper part of posterior opercle.

Length-weight relationships were estimated for three gobiid species of Iran. Significant length-weight relationships with high correlation coefficient were found for all species from eight localities. The value of the parameter b varied between 2.196-2.498 for Boleophthalmus dussumieri (Valenciennes, 1837); 2.554 to 3.460 for Periophthalmus waltoni (Koumans, 1955) and 2.316 to 2.920 for Scartelaos tenuis (Day, 1876).

We collected the specimens of Turcinoemacheilus hafezi throughout the spawning season (January to July, 2012) in Beshar River (south-west Iran) and investigated its age, growth, and reproductive characteristics. The maximum age was 2+ years. Total length and weight of the specimens ranged from 29 to 61 mm and 0.17 to 1.39 g, respectively. Length-weight relationship was estimated as W = 3E-05TL2.57 for females, W = 3E-06TL3.22 for males and W = 1E-05TL2.88 for the population. Sex ratio was 1:1.1 in favor of males. The growth model was isometric for males and sexes combined and negative allometric for females. Based on the gonadosomatic index (GSI) values, spawning appears to occur between late February and late April in Beshar River. The highest mean GSI was 6.73 for males and 14.50 for females in April. The absolute fecundity ranged 42–726 with a mean of 184.87 eggs. Fecundity was also positively correlated with fish size (length and weight). Egg diameter ranged from 0.4 to 1.6 mm with a mean of 0.84 mm.

The head bones and relevant muscles are important elements composing the feeding and respiration apparatus and can be considered as highly important structures for giving rise to evolutionary specializations. The eels of the Anguilloidei is a diverse group and structural diversity in their cranial musculoskeletal system is thus to be expected. Ariosoma gilberti is a member of Bathymyrinae (Congridae) with a hydraulic based prey transport and closely related to muraenid family with mechanical prey transport system. Since there is no information about the cephalic morphology of A. gilbert, hence this study was conducted to provide detailed description of its cranial osteology and myology. The immobile maxillary with large pointed teeth, an anterior moderate mouth gape, large jaw closing muscles and large lateral and ventral bony elements, providing more room for the orobranchial cavity of A. gilberti suggesting the presence of a hydraulic and suction-based mechanism.

To estimate the fish composition and catchability coefficient of gillnet, a survey was carried out during April 2011 to March 2012 in the Shadegan Wetland, Khuzestan Province, Iran. Samples were collected from five stations viz., Mahshar, Rogbe, Khorosy, ‍Salmane and Atish. Approximately 4300 fish specimens were measured and depletion method was used for the estimation of Catchability coefficients of gillnet. Mean±SD q value for Leslie model in different season was 0.008±0.006 and its maximum and minimum values were 0.001 (summer) and 0.004 (spring), respectively. Mean±SD q value for Delury model in different seasons was 0.0007±0.0001 and its maximum and minimum values were 0.002 (summer) and 0.0007 (winter), respectively. Mean±SD of q value for Leslie model in different stations was 0.008±0.006 and for Delury model in different station was 0.003±0.001. Mean catchability value of Leslie model was higher than that for Delury model. Using Students t-test, no significant differences between the calculated Leslie and Delury models among the different stations (P>0.05) and different seasons were observed (P>0.05). A comparison of catchability values showed that there are no significant differences among different seasons (ANOVA, F=0.32, P>0.05) and among different stations (ANOVA, F=0.29, P>0.05).