Behzadi Siamak, Ali Salarpouri, Mohammad Darvishi, Gholam Ali Akbarzadeh Chamachaei, Sajjad Pourmozaffar, Mohsen Gozari, Mohammad Momni,
Volume 9, Issue 1 (1-2020)
Abstract
Aims: Monitoring of the fish biomass is one of the basic principal of fisheries management, but ornamental and reef fish stocks, because of difficulty of estimating their abundance, have been less studied than others. The aim of this study was to estimate the standing biomass of ornamental and reef fishes in Larak Island, in the Strait of Hormuz.
Materials &Methods: Standing biomass of the fish species was assessed seasonally using Underwater Visual Census Method (UVCm) in coral reefs and mesophotic coral reefs in Larak Island throughout 2018 and 2019. Two popular methods in UVCm (belt transect and stationary point) were used based on topography of sea bottom. The confidence interval of estimated standing biomass is calculated using bootstrapping method.
Findings: The standing biomass of ornamental and reef fishes is estimated as 2522.18, 5222.17 and 1325.15(Kg.) in Site 1, Site 2 and Site 3, that are located in 3-15meters depth. The standing biomass at Site 4, was estimated as 884.13kg. The minimum were observed in summer, also the result showed that the standing biomass in summer was significantly lower than other seasons (P <0.05). In addition, the temporal diagnostic test showed that population structure of fish in the spring, autumn, and winter seasons was similar but significantly different from the population structure in summer.
Conclusion: The less of standing biomass in summer season can be affected by seasonal migrations of fish in tropical and subtropical waters to deeper waters, in order to trade of the stresses caused by temperature fluctuations.
Siamak Behzadi, Siamak Darvishi, Ali Salarpoori, Mohammad Momni, Sajjad Pourmozaffar, Reza Dehghani,
Volume 11, Issue 3 (8-2022)
Abstract
Estimation of coral fishes biomass is needed as a basic benchmark for assessing the ecological status and fishing potential of coral reefs. Different methods are used to sampling the biomass of these communities, that direct observation is one of the preferred methods with respect to the non-destructive advantage. The purpose of investigation was to estimation standing biomass of coral fishes by Underwater Visual Census method (UVCm) in Abu-Musa Island seasonally from October 2019 to September 2020. also confidence interval was calculated of these estimations from the bootstrapping test (95%). Standing biomass of Coral fish and their confidence interval (95%) by bootstrapping simulation (n=479) were determinated 2923.6 kg., 4576.2 kg, and 1645.4 kg for the stations one, two and three respectively. The difference in the biomass standing of coral fish in three station could be related to the lack of differences in the amount of developed reefs, coral communities and significant differences in habitat availability. Also, the standing biomass of coral fishes in the Abu-Musa Island are limited, that can be attributed to their low habitat, shortage of carrying capacity and the short life of the Persian Gulf basin, and stress that occurs in the ecosystem, especially bleaching events, that need more study in the future.
Elahe Erfanifar, Saeid Gorgin, Rasul Ghorbani, Adi Susanto, Ririn Irnawati,
Volume 13, Issue 3 (10-2024)
Abstract
To study the effect of baits type and three lights, green, blue, and white, on the fishing efficiency of Largehead hairtail (Trichiurus lepturus) handline fishing 11,951 samples were done from February to May 2022 in the northern coast of the Oman Sea, Remin Fishing Port. The results showed that only the season and bait had a significant effect on the weight and number of caught T. lepturus caught (P<0.05), while the type of lamp and its interactions did not have a significant effect (P>0.05). The highest CPUE was observed in the months of February and March, using Rastrelliger kanagurta as bait, green LED lamp, at a water depth of 60-110 meters, and a hook depth of 20-30 meters. The use of R.kanagurta bait compared to Sardinella gibbosa has led to a significant increase in the catch of T. lepturus (both in terms of relative frequency and weight), which is recommended to improve the efficiency of hook fishing for fishermen. Due to catch per unite effort and for efficiency of catch rate of T. lepturus in the area, it seems suitable bait, green light and suitable depth of the hook must be used.
Ali Salarpouri, Siyamak Behzadi, Reza Dehghani, Moslem Daliri, Mohammad Momeni, Mohammad Seddiq Mortazavi,
Volume 13, Issue 3 (10-2024)
Abstract
| The survey of the fish assemblage in the planned place to establish artificial reefs in the western and eastern bays of Jask was carried out in the winter and spring of 2024. Sampling was done by Gillnet and Trap methods in 4 stations located in the western bay and eastern bay of Jask at a depth of 10 to 30 meters. 68 aquatic species (60 fishes, 5 crabs, 2 oysters, and 1 shrimp) were sampled and recorded. Of these, Nemipterus japonicus (32.6 %) was the most abundant, Saurida tumbil (12.6 %), Anodontostoma chacunda (12.5 %), Ilisha megaloptera (9.8 %), Scomberoides tol (6.4 %), Sphyraena putnamae (4.1 %), Lactarius lactarius (2.6 %), Muraenesox bagio (2 %), Pomadasys kaakan (1.9 %), Otolithes ruber (1.6 %) located in the next rank. The average catch per unit of effort of gillnet was 45±10.2 kg/piece×hour and for Trap 7.3±4.2 kg/trap×day. In this research, it was found that the population of species related to artificial reefs, such as Epinephelus coioides , Lutjanus johnii , and Lethrinus nebulosus were relatively low, and mainly below the maturity size, it seems that the stocks of this group of fish need to be enhanced. Therefore, it is recommended to consider the target species in the design of the structure and arrangement of the artificial reefs, on the other hand, the shelter and protective aspects of the artificial reefs for the reef-dependent juvenile also be considered. |
Mohammad Darvishi,
Volume 13, Issue 3 (10-2024)
Abstract
Tuna fishes are one of the most important and commericial tuna species in Northern of the Persian Gulf and Oman Sea. The tuna fish stocks Thunnus tonggol was assessed in Hormuzgan coastal waters using software FiSAT . Data were collected minimum 200 fish per month simple randomly from five major traditional fish-landing sites in Hormuzgan Province, from November 2021 to September 2023. The monthly individuals ranging of T. tonggol from 21 - 108 cm fork length with mean 71.08 ± 1.23 cm.The infinity length and growth parameters (K, L∞) for T. tonggol, were computed 121.17 cm and 0.68 respectively. Growth performance index (Phi Monreo) calculated for T. tonggol , 8.9 which was in agreement with the finding of the other studies in the Indian Ocean. The results showed that this species has a high growth rate in the first 2 years of their life. The (a, b) parameters in power equation length-weight relationship for T. tonggol were (0.00002, 2.94), indicating that T. tonggol has isometric growth. Total mortality, natural mortality, fishing mortality rate and exploitation ratio (Z, M, F, E) were estimated for T. tonggol (2.89, 0.71, 2.18, 0.75). These results indicated that population of T. tonggol is overexploited and no scope for improving production in Hormuzgan Province. Tuna fish stock are trans boundaries and its fishery management and long term monitoring programs would be conducted in collaboration countries bordering the Persian Gulf, Oman Sea and Indian Ocean
