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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. [ABSTRACT FROM AUTHOR]

The brown meagre (Sciaena umbra Linnaeus, 1758) population has experienced dramatic population declines, and it was regionally assessed as "Near Threatened" in the Mediterranean. In this study, the current status of brown meagre populations in the Black Sea was evaluated by estimating growth and mortality rates based on age readings from the otolith. All specimens were collected by commercial trammel nets between March 2019 and February 2020 in the Turkish coast of the Black Sea. A total of 324 brown meagre were sampled during the study period, ranging in age from 0 to 26. The peak spawning season of the species was from June to July. The Von Bertalanffy growth parameters of (L8 = 54.15, k = 0.14 yr-1, t0 = -3.11) supports previous studies and suggests that brown meagre is a longlived and slow-growing species. The exploitation ratio of 0.53 for females and 0.47 for males. Life-history features and mortalities indicate that the brown meagre has relatively high fertility but may be undefended to intense fishing pressure. However, the impact of overfishing, pollution and climate change can have increasingly detrimental effects on the overall population size of this population. [ABSTRACT FROM AUTHOR]

The study of fishery biology and population dynamics was conducted for Boops boops collected from the commercial catches of gillnets operated in the Egyptian Mediterranean waters off Alexandria. A total of 880 specimens were sampled from the area between Sidi Kirayr to El-Montazah during the period 2018-2020. The length range varied between 11.0 and 20.0 cm TL with a mean of 13.98±1.19 cm and the total weight varied from 14 to 88 g with a mean total weight of 28.51±6.67 g. The length-weight relationship was computed as W= 0.0119 L2.9453 by using total weights and W= 0.0112 L2.9335 by using gutted weights. The mean condition factor (k) was 0.953±0.029 and the overall sex ratio (M: F) was 1.00:0.49. The von Bertalanffy growth parameters were estimated to be K= 0.38 yr-1, L∞= 27.85 cm and tο= -0.443 yr. The growth performance index (Фˋ) was 2.47. The values of natural (M), fishing (F) and total mortality (Z) were calculated as 0.865, 3.845 and 4.710 yr-1, respectively. The current exploitation ratio (Ecur= 0.816) is high reflecting the high exploitation of this species. The yield per recruit and the relative yield per recruit were also studied and the results confirmed that the stock of B. boops is highly exploited and the management of the pelagic gillnets is required. [ABSTRACT FROM AUTHOR]

The waterway from Chongqing to Yibin in the upper Yangtze River provides strong support for the socioeconomic development in Western China, while it also has a negative influence on the river ecosystem, such as river fragmentation, wetland disconnectivity, fish habitat, and biodiversity. Accurately characterizing the exploitation, economic efficiency, and ecological pressure of the waterway from Chongqing to Yibin is of great significance for the further development of the upper Yangtze River. In this study, based on statistical data from the National Bureau of Statistics of China, the waterway development, economic benefits, and ecological pressure of the waterway from Chongqing to Yibin were evaluated. The sustainability index (SI) was introduced to comprehensively assess the sustainability of waterways using the hierarchical model, which integrates the exploitation ratio (ER), economic efficiency index (EEI), and ecological pressure index (EPI). A relatively low ER (41.04%), a low consistency index (CI, 0.31), a high EEI (9037.18 USA$/gha), and a low EPI (0.33) yielded an SI of 0.70, indicating that the waterway from Chongqing to Yibin in the upper Yangtze River is in a sustainable development stage. Compared with the typical global Golden Inland Waterways, the waterway from Chongqing to Yibin still has great development potential under the prioritizing ecological protection. [ABSTRACT FROM AUTHOR]

Tenualosa ilisha, commonly called Hilsa, is a highly prized species, which has declined in River Brahmaputra, India. The study was carried out for one year and a total of 1,026 individuals were sampled at monthly intervals. In the study, the following growth parameters were observed: asymptotic length (L∞) = 445 mm, growth coefficient (K) = 0.5 year-1, and age at length zero (t0) = -0.5 year-1. Growth performance index (φ) was estimated to be 2.996. Natural mortality rate, total mortality, and fishing mortality was found to be 0.51 year-1, 1.57 year-1, and 1.06 year-1,respectively. Exploitation ratio (E) was found to be 0.675, which indicates that the species is slightly over-exploited. It was seen that length groups that represented the catch in the Indian part of River Brahmaputra comprised fishes of 0–4+ years age. The present study was carried out to assess the population characteristics of this commercially important species from the Indian part of Brahmaputra River, which will contribute towards sustainable fisheries management. [ABSTRACT FROM AUTHOR]

Population characteristics and exploitation level of Anabas testudineus from Rudrasagar lake, North-eastern India were studied to understand the dynamics of resource for suggesting necessary strategies for sustainable exploitation. A total of 1187 specimens were sampled to collect the length frequency data from May, 2015 to April, 2016. The length-weight relationship of the fish was found to be Log W = - 4.08+2.9 LogL (r²=0.99). The Von Bertalanffy growth parameters i.e., asymptotic length (L∞)and growth coefficient (K) were estimated using ELEFAN-I as 216.25 mm and 0.78 yr- 1respectively.The growth performance index (φ') was calculated as 4.56. The approximate longevity (Tmax) was estimated as 3.8 years. The total mortality (Z), natural mortality (M) and fishing mortality (F) rates were estimated to be 1.95, 1.54 and 0.41 per year, respectively. The exploitation ratio (E) and exploitation rate (U) were observed to be 0.21 and 0.18, respectively. The results of relative yield-per-recruit (Y'/R) and relative biomass-per-recruit (B'/R) estimated as a function of Lc/L∞ and M/K were 0.46 and 1.95 respectively. The MSY level was estimated at 3.8 tonnes per year at F factor-0.8. Since the current level of exploitation of the species is well below Emax(0.50) and the observed landings are lower than the MSY level, it could be concluded that the fish is presently underexploited in the Lake. Reasonable fishing effort can be increased in order to obtain more yields so as to reach the MSY level and in that way increase the income of the economically poor fishermen communities of North-eastern India. [ABSTRACT FROM AUTHOR]