Cephalopods are mostly targeted by trawlers and Sepiella inermis (spineless cuttlefish), contributes about 2-4 percent of total cephalopod landings in India. Cephalopods accounted for 6.9 percent of total landings in Gujarat in 2018, with S. inermis accounting for approximately 1 %. The most common length of this species in the fishery is between 35 mm to 147 mm. The length at first sexual maturity varies along the coast, and recent estimates for west coast of India for this species is 48 and 55 mm for males and females, respectively.
There are no estimates of trawl codend selectivity for this species and experiments were carried out using a 40 mm diamond mesh codend using covered codend method. The selection parameters for S. inermis were derived using SELECT methodology and the length at 50 % retention (L50)±(s.e.) was worked out as 36.2±1.2 mm and selection range as 19.9±2.1 mm. The selection factor and the selection ratio for the codend were worked out as 0.9 and 0.55, respectively. The suggested mesh size for the codend based on length at first sexual maturity (LFM) of females (55 mm) and males (48 mm) were estimated as 60 and 53 mm (diamond mesh), respectively. This is the first estimate of trawl selection for this species and operational parameters like towing speed, codend catch etc., that could influence selectivity were not considered and hence more studies by incorporating these factors will help in further refining the parameters of the selection curve.

中文翻译：

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在 40 毫米菱形网状编码拖网中对无头无花木贼（Van Hasselt，1835 年）的选择性估计

头足类动物主要是拖网渔船和无刺乌贼（Sepiella inermis）的目标，约占印度头足类动物总登陆量的 2-4%。2018 年，头足类动物占古吉拉特邦总上岸量的 6.9%，S. inermis 约占 1%。该物种在渔业中最常见的长度在 35 毫米到 147 毫米之间。沿海地区第一次性成熟时的长度各不相同，最近估计该物种在印度西海岸的雄性和雌性分别为 48 毫米和 55 毫米。
没有对该物种的拖网编码器选择性的估计，使用 40 毫米菱形网孔编码器和覆盖编码器方法进行了实验。S. inermis的选择参数使用 SELECT 方法得出，50% 保留时的长度 (L50)±(se) 计算为 36.2±1.2 mm，选择范围为 19.9±2.1 mm。编码器的选择因子和选择比分别计算为 0.9 和 0.55。根据雌性（55 毫米）和雄性（48 毫米）的第一次性成熟（LFM）长度，建议的编码网尺寸分别为 60 和 53 毫米（菱形网）。这是对该物种的拖网选择的第一次估计，并且未考虑可能影响选择性的操作参数（如拖曳速度、捕捞量等），因此通过纳入这些因素进行更多研究将有助于进一步完善选择曲线的参数。