Phenotypic plasticity of shell shape and growth of mussels to environmental conditions: Mytella strigata in the southeast Gulf of California

The shape of the shell and the development of bivalve mollusks are strongly associated with the action of environmental conditions. The environmental variables, functional parameters of the shell, and the relative growth of Mytella strigata were seasonally (summer 2020 to spring 2021) determined in three locations: Altata Bay (AB), Macapule Lagoon (ML) and El Colorado Bay (CB) from the southeast Gulf of California (Mexico). Shell dimensions (SL: shell length, SH: shell height, and SW: shell width) showed significant differences. ML mussels obtained the highest measurements (SL = 19.12 ± 1.60 mm, SH = 47.67 ± 3.92 mm, SW = 14.92 ± 1.04 mm, and body weight = 7.54 ± 1.40 g). The greatest shell elongation (SH/SL) was observed in ML (2.49 ± 0.13), while CB recorded the highest compactness and convexity values. SH/SL was the most substantial interaction (R2 = 0.67, 0.63, and 0.55 in AB, ML and CB, respectively). The principal component analysis shows three groupings of the biometric indicators and the relative growth of mussels concerning the environmental parameters in each lagoon. The environmental conditions affected the shape of the shell and relative growth of M. strigata in the three lagoons, emphasizing the type of habitat and salinity as the determining factors. The shell phenotypic plasticity of this mussel represents an adaptive strategy of resilience to the environmental factors in each place.