The effect of temperature on the inhalant siphon regeneration of Amiantis purpurata (Lamarck, 1818) (Bivalvia; Veneridae)

Abstract

The purple clam Amiantis purpurata inhabits intertidal and shallow subtidal platforms from San Matías Gulf, Argentina to Santa Catarina, Brazil. This edible bivalve is an important component of the marine trophic webs due to siphon nipping. The present study investigates the influence of temperature on the regeneration of the inhalant siphon tentacle crown of A. purpurata. Under laboratory conditions 140 purple clams were exposed to four different temperatures (12, 15, 20 and 22°C). At each temperature, the distal 0.5 cm of the inhalant siphon was removed from each clam. The length of long tentacles from each group was measured on different days until the tentacles had reached asymptotic growth. Four candidate models were used for each tentacle data set for growth at the four experimental temperatures. The data were fitted to size-increments for the long siphon at different temperatures using maximum likelihood. The von Bertalanffy model was the one that best fitted the data at most experimental temperatures. To evaluate differences in tentacle regeneration in each treatment, the growth parameters were compared using a likelihood ratio test. The two interdependent parameters affecting the regeneration process k (growth constant) and t ip (inflexion point), were clearly influenced by temperature. In the case of k, increasing temperature produces acceleration in the regeneration process while t ip is not dependent on temperature. Regeneration was slower than in any other species previously reported in the literature and decreasing temperature slowed down the process.