Age, growth and mortality in four populations of the boring bivalve Lithophaga patagonica from Argentina

BAGUR, MARIA; RICHARDSON, CHRISTOPHER A.; GUTIÉRREZ, JORGE LUIS CEFERINO; ARRIBAS, LORENA PILAR; DOLDAN, MARIA DEL SOCORRO; PALOMO, MARIA GABRIELA

JOURNAL OF SEA RESEARCH

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2013 vol. 81 p. 49 - 56

1385-1101

The boring bivalve Lithophaga patagonica (d´Orbigny, 1842) is a locally abundant inhabitant of hard substrata in the coastal waters of the Southwestern Atlantic. In this paper we describe the growth and age of three intertidal rock-boring populations of L. patagonica and one subtidal oyster shell (Ostrea puelcheana), boring population. An analysis of acetate peel replicas of shell sections showed that L. patagonica slows down its growth during autumn-winter, which leads to changes in the direction and rate of shell deposition and the formation of conspicuous annual (low temperature induced) clefts in the shell margin. Cleft counts and Von Bertalanffy growth analyses indicates a maximum lifespan of 15 years for L. patagonica, with noticeable variations in longevity between populations e.g. 6.5 years in the oyster boring populations. Maximum asymptotic length (L∞) and Von Bertalanffy growth constant (K) were also variable between populations (L∞ between 14.76 and 36.95 mm and K from 0.20 to 0.90 yr-1 respectively). Mortality rates and population structure also differed between sites. Type (rock vs. oyster), composition and hardness of the substrata are likely the main factors controlling the observed differences between populations.