A study on industrial fisheries of tuna fishes in Oman Sea

Some investigation were performed on the industrial fisheries of tuna in Oman Sea in 1996. The result showed that the total fisheries of Spanish purse seiners, Montelape & Montealegre, were more than 8907 tons; yellow fin tuna (91%) and longtail tuna (9%) from March to September 1996. Their activity was in the Indian Ocean from September 1996 to March 1997. Using Jahadpozm longliner, 204 tons of tuna including yellow fin tuna (99.2%) and swordfish (< 1%) were fished in Oman Sea during a 9 month period in the years 1995 & 1996. The CPUE of these purse seiners were 40 tons per fishing day which was noticeable in comparison with 21 tons of purse seiners in the Indian Ocean and indicated the richness of EEZ of Oman Sea. Longtail tuna mostly were fished by Spanish vessels in western regions of 600 longitude and yellow fin tuna were caught from 57º to 62º longitudes in Oman Sea. Comparing the length distribution of yellow fin tuna caught by industrial and artisanal fisheries showed that the larger size of exploited fish by purse seiners were generally bigger than those caught by artisanal vessels

Survey on source of yellowfin tuna (Thunnus albacares) in Hormozgan Province, Iran

Survey was made for determination of some biological parameters of Yellowfin tuna in Hormozgan province (during 1995 to 1996) and it was determined that catch of above mentioned species in 1996 by gillnet was nearly 1133 tons. Comparing the length of the fish caught by industrial way with traditional way shows the bigger sizes were caught in industrial way. Yellowfin tuna was caught in the east Hormozgan strait specially Kouh-Mobarak and Gask to Meidani areas and the peak of hunting time was in April and September to December months.The maximum length of Yellowfin tuna was 158 cm and the minimum was 38 cm. The relationship between their weight and length was W=6.2 x 10-5 L 2.7283. Their length and weight coefficient were estimated by these formula:L∞=181.62 cm, K=0.54 y-1, and natural mortality, fishing mortality and total mortality are: Z=2.37, F=1.67 and M=0.70

Some biological aspects of 8 marine species of Hormozgan

A Study was carried out on spawning season, feeding and some environmental conditions of 8 aquatic species of Hormozgan sea waters from Oct. 91 to Mar. 93. The results showed that spawning peak for Otolithes ruber, Psettodes erumei, Pomadasys kaakan, Arius thalassinus and Arius tenuispinis occurred in spring, for Pampus argenteus and Parastromateus niger occurred in summer, and for Sopia pharaonis occurred in Autumn. Two summer spawner and two Arius species were appeared Lo he very gluttonous and other spring spawner species showed rather less tendency for feeding P. argenteus appeared to eat copepod and rhizosolenia and P. niger stomach contents included nematode and annelid worms and also copepod, P. erumei feeds on small fishes and others eat crustacean and small fishes too. High growth coefficients for P. argenteas and A. renuispinnis a medium growth coefficient for P. niger and low growth coefficients for other species were obtained. Except for S. pharaonis, geographical distribution did not differ significantly (α<0.05). The zooplankton and phytoplankton were identified with different monthly and locally densities Depth pH and salinity had little variation in spawning seasons, mean dissolved oxygen and water depth temperature ranged between 3.48 to 6.05 and 21.85 to 31.05 respectively (α <0.05)

Reproduction and spawning patterns of the Scomberomorus commerson in the Iranian coastal waters of the Persian Gulf & Oman Sea

Reproduction and spawning patterns of the king fish (Scomberomorus commerson) were studied in the Persian Gulf (Hormozgan Province) and Oman Sea from Oct 2006 to Sep 2007. A total of 1120 fish was collected from different landing sites along the Iranian waters. Yearly analysis of the reproductive stages and gonadosomatic index showed a single reproductive cycle beginning in March and continued with a single spawning period from August to September. The mean length at first maturity (Lm 50%) for females was 83.6 Cm. The sex ratio was M:F = 0.97:1 which was not significantly (P > 0.05) different among samples (χ2 test). Isometric growth for this species was approved

Investigation of genetic variation and sexual diversity of different populations of Gracilaria corticata in the Persian Gulf and Oman Sea using ISSR markers

ISSR markers were used to determine the genetic variation and sex determination of the three life-stages of 41 samples of Gracilaria corticata from two regions of the Persian Gulf and Oman Sea namely Bostaneh and Lipar. The specimens were cultured in PES media to observe the different life stages. DNA was extracted by modified CTAB method. After screening of 20 ISSR primers, four primers were selected that produced clear reproducible fragments and were suitable to find sexual diversity for further analyses. The four primers generated 75 bands ranging from 250 to 3000 bp, corresponding to an average of 18.75 bands per primer. A set of four anchored primers amplified 75 bands out of which 100% were polymorphic among 41 samples. PIC value ranged from 0.28 to 0.33 and marker index ranged from 4.48 to 6.51 per primer. The mean value of Shannon’s index was 0.45. By using primer "AB","ABC_1" were identified three life stages of this alga. Primers "A" and "C" were also able to detect diploid tetrasporophyte but haploid males and females were determined by "A" and "C" respectively. Gst value was 0.058, indicating that 83% of the genetic diversity resided within the population. Clustering analysis using WARD algorithm based on Nei's Unbiased Measures of Genetic distance, classified the G. corticata individuals into five major groups. The PCOA data confirmed the results of clustering. The results of this study reveal that ISSR markers could be used efficiently for genetic differentiation of G. corticata individuals in different regions

Morpho-anatomical studies on red alga Gracilaria corticata in the Persian Gulf and Oman Sea

The speciemns of red algae “Gracilaria corticata” were collected from the rocky intertidal shores in Bostaneh Port in the Persian Gulf and Lipar in Oman Sea in May, June and August 2013. Anatomical, morphological structures, thallus of vegetative and reproductive samples were studied. Carpogonial and tetrasporangium stages were determined based on histological and morphological methods. The female thallus, the Cystocarp with hemispherical structure through out thallus were observed. The Spermatangial conceptacle was located deeper as the oval shape in male thallus. The tetrasporophytic stage of diploid samples was determined by the presence of tetrasporangium oval shape

The study on fishing and resource management of kilka fisheries within southern Caspian Sea

The project of the Study on fishing and resource management of fisheries within Southern Caspian Sea was conducted on the base of an agreement made between fisheries organization (Shilat) and the Iranian fishery research organization (IFRO) signed in 2010. The study has several phases. The final report of the fishery on fishing and resource management of fisheries within Southern Caspian Sea (Gilan, Mazandaran & Golestan provinces) is consisted of several sections such as: 1- The Survey status of biology and catch of Kilka fishes , Bony fishes and Estrogen fishes and also the status of aquatic resource conservation in the Southern part of Caspian Sea 2- Fishing analysis in the Southern part of Caspian Sea 3- Fisheries development Strategies, policies and plans in the Southern part of Caspian Sea In this survey and library-based study, internal and external environmental factors of shilat activities are considered. Using SWOT analysis method, current situation of fisheries is investigated. In this regard, all fisheries activities were divided into four groups, then, the strengths, weaknesses, opportunities and treats of internal and external environment will be analyzed. A considerable number of tables and matrixes were prepared and policies and strategies as seen of final report were carried out

The study of fluctuation of large pelagic stock (yellowfin tuna, skipjack tuna, longtail tuna, Narrow-barred Spanish mackerel) in order to optimum exploitation in the Persian Gulf & Oman sea

The study of fluctuation of large pelagic stock (yellowfin tuna, skipjack tuna, longtail tuna, Narrow-barred Spanish mackerel ) in order to optimum exploitation in the Persian Gulf & Oman sea This study was carried out from 2005-07 in order to acquire some biological characteristics and population dynamic parameters for stock management and responsible fisheries. Thunnus albacares (yellowfin tuna), katsuwonus pelamis (skipjack tuna), Thunnus tonggol (longtail tuna) and scomberomorus commerson (Narrow- barred Spanish mackerel) were sampled. In total, length frequency of 9345 specimens of yellowfin tuna were analyzed. Size range was 37-172 cm. Teleost fishes were the most dominant prey species observed in this study (42%), Occurrence of Potunus Pelagicus was found to be the second (28%).Sthenoteuthis oualaniensis (22%), Natosquilla (5%) and octopus (3%) also were identified in the gut content of the yellowfin tuna. Length of maturity (50%) of yellow fin tuna was estimated 77.2 cm and spawning season was started from May. 8443 specimens of skipjack with size range of 32-90 cm were sampled. 48% of food items were teleost fishes. Squid and shrimp were also identified. Spawning season was begun from June. Growth parameters & fishing mortalities of yellow fin tuna and skipjack tuna were also estimated. Size range if longtail tuna was from 26-125cm Length infinity was estimated 132.3 cm with growth parameter of 0.35 per year. In total 10451 specimens of narrow- barred Spanish mackerel were sampled. Size range was from 20-164 cm. Teleost fishes were the most dominant prey species observed in the study (91.3%). Crustaceans (0.6%) and Indian squid (0.2%) also were identified in the specimens. Length maturity (50%) was estimated 83.6cm

The study on fishing and resource management of bony fisheries within southern Caspian Sea

The project of the Study on fishing and resource management of fisheries within Southern Caspian Sea was conducted on the base of an agreement made between fisheries organization (Shilat) and the Iranian fishery research organization (IFRO) signed in 2010. In this library-based study the current situation of bony fish fisheries and biology of these species has been surveyed in Iranian waters of the Caspian Sea . In this survey internal and external environmental factors of bony fishes activities were considered. Using SWOT analysis method, current situation of fisheries was investigated..One of the most important strategies for conserving anadromous species such as Caspian kutum , common carp, roach, bream and …. is rehabilitation of the natural spawning ground in rivers, coastal lagoon specially Anzali lagoon .By conducting this strategy not only restocks of bony fishes is done ,but also reduced the cost of artificial restocking programs and releasing fingerlings .In short term , it is nessesary to enhance the stocks of the species that have low catch is done by huge releasing of the fingerlings and study the qualification of the program

Biomass estimation of demersal resources in the Persian Gulf and Oman Sea by swept area method

Regarding to monitor of demersal resources in the Persian Gulf and Oman Sea, and also biomass and CPUA estimation of them, ten research cruises were carried out by using R/V Ferdows-1 equipped with bottom trawl, covering the area from 49º 00´ E in the west (north-west Persian Gulf) to 61º 25´ E in the east (borderline with Pakistan) from 2012 to 2014 The study area was stratified into 17 strata (A to Q) of which 10 strata (A to J) were in the Persian Gulf and 7 strata (K to Q) were in the Oman Sea, covering the depths of 10-50 m in the Persian Gulf and 10-100 m in the Oman Sea. A total of 316 stations were randomly selected and the biomass and CPUA were estimated by swept area method during this three years period, the strat A and B weren’t covered. The comparison between two regions indicated that the percentage of density of demersal fishes in the Persian Gulf during years 2012, 2013 and 2014 were 1.0, 1.4 and 1.6 times more than the Oman Sea and totally 50-60% of total biomass was found for the Persian Gulf. Also a comparison among 17 strata the highest biomass was found for K region (Sirik to Jask) in the Oman Sea in 2012 & 2014; and C region (Genaveh to Bordkhoon) in 2013 in the Persian Gulf. The same comparison was done for CPUA of commercial, non-commercial and total in both water bodies and it was found that in years 2012 to 2014 the region K (Sirik to Jask) in the Oman Sea and Stratum Q (Bersi to Gwatr) had the highest value of CPUA. On the contrary, the stratum M (Biahi to Galak estuary) showed the lowest value of biomass for both commercial and non-commercial fishes. With review the mean CPUA in different depth layers for years 2012, 2013 and 2014, it was concluded that in the Oman Sea with increasing the depth, the mean CPUA is decreased and the lowest CPUA belongs to depths of 30-50 m The comparison between commercial and non-commercial groups in both ecosystems, it concluded that the density of commercial species were higher than non-commercial ones; and for years 2009, 2010 and 2011 the commercial species consist of 63.4, 65.0 and 59.7 % of total biomass. In all years the Persian Gulf indicated higher values than the Oman Sea. The most abundant fishes were Rays, Ribbon fishes, Carangids, Grunts, Japanese threadfin bream, Lizardfish and Barracuda for both Persian Gulf and Oman Sea