Islam Md Monzurul, Rahman Md Habibur, Sultana Mst Afia, Rahman Md Ataur, Hossain Md Yeamin, Choudhury Moumita, Rahman Md Anisur
Department of Fisheries and Marine Bioscience, Jashore University of Science and Technology, Jashore-7408, Bangladesh.
Ministry of Public Administration, Bangladesh Secretariat, Dhaka, Bangladesh.
Heliyon. 2024 Feb 29;10(5):e26751. doi: 10.1016/j.heliyon.2024.e26751. eCollection 2024 Mar 15.
This study was conducted to observe the stock assessments of in three different management systems of (Oxbow lake) such as System-1, System-2, and System-3. In this study, 1806 specimens were sampled using traditional fishing nets to observe growth pattern, population structure, growth parameters, natural mortality (), fishing mortality (), total mortality (), recruitment pattern, exploitation rate (), relative yield per-recruit (), optimum catchable length, length at first capture, steady state biomass (), and maximum sustainable yield () from January to December 2021. Digital slide calipers and a digital balance were used to measure each individual's total length () and body weight (), respectively. An empirical maximum length-based model was used to calculate size at first sexual maturity (), and optimum catchable length () was calculated based on asymptotic length (). The least square linear regression equation was used to determine the regression parameters. The value of regression parameter, '' was 3.01 for system-1, 2.78 for system-2, and 2.70 for system-3, indicating that growth pattern of is isometric in system-1, but negative allometric growth in system-2 and system-3. The highest asymptotic length () and weight () of were found in system-1 (11.19 cm and 13.67 g) in comparison with system-2, (10.98 cm and 12.49 g) and system-3 (9.09 cm and 6.96 g) respectively. The growth coefficient () of the von Bertalanffy growth function (VBGF) was 0.72 year, 0.72 year, and 0.73 year for system-1, system-2 and system-3, respectively. The calculated were 1.72, 1.28, and 3.00 year for system-1, 1.11, 0.67 and 1.78 year for system-2 and 1.12, 0.84 and 1.96 year for system-3 respectively. The calculated life span () was found 4.19 years for system-1, 4.15 years for system-2 and 4.12 years for system-3. The recruitment patterns showed that the highest relative percentage of recruits were found in July, June and September for system-1, system-2 and system-3 respectively, with the major recruitment peak occurring from April to June for system-1, May to June for system-2 and June to July for system-3. One minor recruitment peak also occurred from August to September in system-1. The exploitation rate was more or less same in all three systems indicating that is under exploited from all the . The significantly highest and were found in system-1 (22.65 and 12.11 metric tons), compared to system-2 (16.16 and 10.28 metric tons) and system-3 (5.55 and 5.49 metric tons), respectively. Considering the values of regression parameters, recruitment pattern, and , system-1 was found more suitable for compared to system-2 and system-3 management practices of . Finally, these findings will turn out to be paradigm for the impregnable management of in of southwest Bangladesh.
本研究旨在观察在三种不同管理系统（如系统1、系统2和系统3）下（牛轭湖）的种群评估情况。在本研究中，于2021年1月至12月期间，使用传统渔网采集了1806个样本，以观察生长模式、种群结构、生长参数、自然死亡率（）、捕捞死亡率（）、总死亡率（）、补充模式、开发率（）、单位补充量相对产量（）、最佳可捕长度、首次捕获长度、稳态生物量（）和最大可持续产量（）。分别使用数字游标卡尺和数字天平测量每个个体的全长（）和体重（）。采用基于最大长度的经验模型计算初次性成熟时的体长（），并根据渐近长度计算最佳可捕长度（）。使用最小二乘线性回归方程确定回归参数。系统1的回归参数“”值为3.01，系统2为2.78，系统3为2.70，这表明在系统1中呈等速生长模式，而在系统2和系统3中呈负异速生长。与系统2（10.98厘米和12.49克）和系统3（9.09厘米和6.96克）相比，系统1中的（11.19厘米和13.67克）具有最高的渐近长度（）和体重（）。冯·贝塔朗菲生长函数（VBGF）的生长系数（）在系统1、系统2和系统3中分别为0.72年、0.72年和0.73年。系统1的计算值分别为1.72、1.28和3.00年，系统2为1.11、0.67和1.78年，系统3为1.12、0.84和1.96年。计算得出系统1的寿命（）为4.19年，系统2为4.15年，系统3为4.12年。补充模式表明，系统1、系统2和系统3分别在7月、6月和9月发现补充个体的相对百分比最高，系统1的主要补充高峰出现在4月至6月，系统2为5月至6月，系统3为6月至7月。系统1在8月至9月也出现了一个次要补充高峰。所有三个系统中的开发率大致相同，表明在所有这些系统中均未得到充分开发。与系统2（16.16和10.28公吨）和系统3（5.55和5.49公吨）相比，系统1中显著最高的（22.65和12.11公吨）。考虑到回归参数值、补充模式、和，与系统2和系统3对的管理实践相比，系统1被认为更适合于。最后，这些发现将成为孟加拉国西南部牛轭湖对进行稳固管理的范例。
