Shell dimension-weight relationships in the blood cockle Larkinia grandis (Bivalvia: Arcidae) on the southeastern coast of the Gulf of California

Abstract

The blood cockle Larkinia grandis is a commercially important resource in the Gulf of California, but little information is available on this species. In this study, the interactions between body weight (BW) and shell length (SL), height (SH), and width (SW) were evaluated in a L. grandis population in the Gulf of California, Mexico. Eighty cockles were hand-picked monthly from August 2017 to July 2018 near and/or under mangrove trees on the southeastern coast of the Gulf of California. The range of shell measurements (SL = 142.00-44.57 mm, SH = 85.50-31.15 mm, SW = 76.56-32.03 mm) indicates that the sampled population was dominated by adult specimens. Only the coefficient of variation for BW exhibited high dispersion (23%-45%). The potential relationships between BW and SL, SH, and SW were non-linear. The strongest interaction was found between BW and SW (R 2 = 0.934), with the BW-SW relationship best describing the growth of this ark clam. All shell dimension-weight relationships were significant (P ≤ 0.05), indicating both negative (SL-SW and SH-SW) and positive (SL-SH, BW-SL, BW-SH, and BW-SW) allometric growth. The b values ranged from 0.8950, for the LogSH-LogSW relationship, to 2.6240, for the LogBW-LogSH interaction. This preliminary information is useful for developing conservation and sustainable exploitation strategies for this species, which is of economic importance to this region.

Estimation of Growth and Size at First Maturity under a Multimodel Approach of Anadara tuberculosa (Sowerby, 1833) on the Southeast Coast of the Gulf of California

“…Parameter b of the L-W ratio indicates that the relative growth of A. tuberculosa is of a positive allometric type; this behavior is usually expected for the species, as reported by Alemán et al [7] for females and males (b = 3.19 and 3.13); however, when combining both sexes and deriving a representational population with heights lower than the minimum reported height (31 mm), the value of b was estimated at 2.46, which implies negatively allometric growth, that is, the growth is greater in terms of height than weight. This same behavior was reported by Sotelo-González et al [37] for L. grandis; however, they found a greater distribution of between 31 and 142 mm. The alternation between positive and negative allometry may be associated with environmental variations or reproductive aspects, as has been reported for A. tuberculosa and other species [15,38].…”