Iranian Scientific Fisheries Journal
Year:2000 | Volume:9 | Issue:1|Papers Count:10

This research was done in Tonekabon river in 1996. The results indicated that the Tonekabon river fishes belong to 5 families as Salmonidae, Cyprinidae, Athenrinidae, Cobitidae and Gobiidae. The most frequency (89.4 %) and distrubution of Salmonidae situated in upstream of the rivers belong to salmo trutta fario. From Cyprinidae, Alburnoides bipunctaus with 26.4%, Capoeta capotea with 19.9% and Barbus lacerta with 5.9% had the maximum frequency and distribution along the rivers comparing to other species. From Gobiidae, Neogobius melanostomus with 8.3% and from Cobitidae, Cobitis taenia with 7.3% had the maximum frequency. The amount of variety and accurence on species were increasing from up to the end of the river and the minimum was zero and the maximum were 1.997 and 2.173 in river basin respectively.

According to recognition and abundance of larve of commercial fish, caught during shrimp fishing season in eastern Chahbahar in the period of 7 to 27, November 1999, sampling was conducted from catch component during this time. Randome sampling was done 3 days a week for 3 weeks. Catch composition in this research divided to six groups, Osteal fish with 92.88% and Echinoidae with 0.12% has maximum and minimum frequency respectively. In catch composition 45 different marine species were identified and between commercial fish, 8 species were studied, but more study was done on Pampus argenteus, which has the most aboundance. It has the maximum frequency in length 8 and 10cm. The minimum and maximum size of this species was 3 and 19.5cm, respectively. Besides this research was determined all commercial fish catched in larvale and juvenile stage.

During a survey on parasitic worms infection of local freshwater fishes in years 1994-95 in Khouzestan province wetlands, 206 individuals of fishes (62 individuals of Barbus luteus Heckel, 1843; 30 individuals of Cyprinus carpio L.; 6 individuals of Silirus triostegus Heckel, 1843; 92 individuals of Liza abu Heckel, 1843 and 15 individuals of Aspius vorax Heckel, 1843 of Hoor -al- azim and Hoor- shadegan were catched and they were examined. One of 62 B. luteus and two of 3 C. carpio were infected to Borthriocephalus opsariichthydis Yamaguti, 1943 and two of 6 S. triostegus were infected to proteocephalus sp. Weinland, 1858. In this study, frequency of infection in B. luteus and C. carpio to B. opsariichthydis was 1.6% and 6.6% respectively, and in S. triostegus was 33.3% to proteocephalus sp. One of 15 A. vorax and 51 of 93 L. abu were infected to Neoechinorhynchus tylosuri. In this study female and male parasites were collected from fish intestine. Frequency of infection in A. vorax and L. abu were 6.6% and 54.8% respectively. This is the first record of N. tylosuri infection in A. vorax in Iran.

Identification of seaweed in Sistan & Baluchestan province was carried out from Gwatr area (with 25°, 10´ N , 61°, 30´ E) to Mydani (25°, 24´ N, 59°, 5´ E) during one year (starting from December 1998 to November 1999). Seasonally sampling in subtidal area (by diving) and monthly sampling in interidal area, were done. The samples were transfered to the lab and fixed with formalin 4%. The seaweed were recognized according to the present references. The photographs were taken and herbarium sheet obtained. The samples were send to experts (such as Dr. Tesng from China, Dr. Wynne from USA and Ms. Qari from Pakistan) for final approval. During this research 83 species (68 of which were recognized as species and 15 as genus) were identified. Among identified seaweeds, there are some important ones such as: Green seaweed (Ulvaceae, Ulvales); Red seaweed (Gigartinales, Gilidaceae, N emalia1es, Hypneaceae, Gracilariaceae) and Brown seaweed (Sargaceae, Fucales).

The length frequency, sex ratio and CPUE of Arass reservior crayfish have been studied during a one year research project in 1997-98. Camparison of Arass crayfish with the same species of crayfish dwelling in freshwater habitatus of Turkey, Turkamenistan, Caspian sea region and also in Anzali lagoon, The Arass crayfish were higher in length and weight. The average length and weight were 120.50±0.96mm and 54.68±1.53 gr, respectively (n=3219, confidence interval 95%). In the samples, the smallest crayfish measured 78mm and weighted 12.3gr and the largest crayfish had 186mm length and 239.6 gr weight. In the crayfish traps 83.2% of catch exceeded the standard commercial size. The sex ratio during spawning period (December May) dominated by males and in other months the females had superiority in the catch. In general consideration the sex ratio during the project life dominated by males (1:1.33, n=35454). The CPUE in August was the highest and the least in January (in order of 10.32 and 0.15 crayfish per one trap in 24 hours respectively). The catching operation occured in the depth of 2.5-17.5mm in the ecosystem, and CPUE were the highest the depth of 75mm. Considering the CPUE data, the desirable catch occured in the August, September and October. Positive relationship between water temperature and CPUE observed, and optimum catch were occured when the water temperature ranged between 16-26°c.

Largehead hairtail (Trichiurus lepturus), an important commercially species of the family of Trichiuridae, is found in aboundance in the Persian Gulf and the Oman Sea. The feeding of this fish was studied from November 1995 to October 1996 in Meydani area, a area of the Iranian waters of the Oman Sea which is placed between J ask and Chahbahar parts. Stomach content of 587 specimens of hair tail were studied and classified as full, semifull and empty. The frequency of full, semifull and empty stomachs were 15%, 17% and 68% respectively. Minimum feeding obtained in April and March and maximum in August. The Vacuity index (CV) was 68.1 and food prefect (Fp) of stomach content assiged which was for eaten fishes 70.1%, crustacea 16% and molluscs 13.9%, so fishes were determined as main food. The most frequent food item of stomach content was anchovey (Stolephorus sp.)

This is the first record of Rhinogobius similis (Gobiidae), an exotic fish species in Iran. The results of this study show that a limited number of this species live in Harir-rud on Iran, Torkman Border. The morphometric and morphological characters of this species in Iran are similar to these from Japan and Korea.