Faculty of Fisheries, Muğla Sıtkı Koçman University, 48000, Muğla, Turkey.
Faculty of Fisheries, Ege University, 35100, Bornova, Izmir, Turkey.
Sci Rep. 2022 Jul 18;12(1):12256. doi: 10.1038/s41598-022-16611-7.
Length-weight relationship (LWR) studies have been widely conducted for fish. They are important because they provide information about the growth of the fish, its general wellbeing, and fitness in a marine habitat. In comparison, relatively few LWR studies have been conducted on cephalopods. A total of 13,474 specimens belonging to 28 cephalopod species was investigated to define their length-weight relationship status and Fulton's condition factors, and compared with previous studies to evaluate life history traits and test comparability of LWR values. Isometry was found in 8 species including 2 teuthids, 2 sepiids and 4 octopods, and positive allometry was found in 2 squid species. Other species showed negative allometry. Four orders of the class Cephalopoda distributed in the Mediterranean Sea were also compared in respect of their coefficient b values, and a clear distinction was found between the orders reflecting their characteristic body types and thus lifestyles. Coefficient b values of mature animals were found lower than that of maturing ones that reflects growth of semelparous cephalopods stops or at least slows down when they reach maturity. Some extreme condition factor values were calculated for especially octopods that one of them reached to 140.91 in a deep-sea octopus Pteroctopus tetracirrhus. It suggests that there are many factors that might affect the calculations. Some of them were: different body structure and growth type in cephalopods than that of fish, different length measurement method applied in cephalopods, different body parts that might have different growth rates, and preservation methods that could affect the body shape and weight in soft bodied animals.
长度-重量关系 (LWR) 研究已广泛应用于鱼类。这些研究非常重要，因为它们提供了有关鱼类生长、整体健康和在海洋生境中适应性的信息。相比之下，关于头足类动物的 LWR 研究相对较少。本研究共调查了 13474 个头足类标本，以确定其长度-重量关系状态和富尔顿的条件因子，并与以往研究进行比较，以评估其生活史特征并检验 LWR 值的可比性。结果发现 8 种头足类动物呈等比关系，包括 2 种枪形目、2 种乌贼目和 4 种章鱼目，2 种鱿鱼目呈正异速生长，其他物种呈负异速生长。地中海分布的头足纲四个目也在其系数 b 值方面进行了比较，结果发现它们之间存在明显的区别，反映了它们特征性的体型和生活方式。成熟动物的系数 b 值低于成熟动物，这反映了一次性头足类动物在达到成熟时生长停止或至少减缓。一些极端的条件因子值被计算出来，特别是章鱼目，其中一种深海章鱼 Pteroctopus tetracirrhus 的条件因子值达到了 140.91。这表明有许多因素可能会影响计算结果。其中一些因素包括：头足类动物的身体结构和生长类型与鱼类不同，头足类动物应用的长度测量方法不同，可能具有不同生长速度的身体部位不同，以及可能影响软体动物体型和体重的保存方法。
