Population structure, distribution and harvesting of Southern geoduck, Panopea abbreviata, in San Matías Gulf (Patagonia Argentina)

MORSAN, ENRIQUE M.; ZAIDMAN, PAULA CECILIA; OCAMPO-REINALDO, MATÍAS; CIOCCO, NÉSTOR

SCIENTIA MARINA

INST CIENCIAS MAR BARCELONA

Lugar: Barcelona; Año: 2010 vol. 74 p. 763 - 772

0214-8358

Southern geoduck is the most longevous bivalve species under exploitation in the South Atlantic. However, except preliminary data about growth and a gametogenic cycle study, there is not information basic to manage this resource as populational structure, harvesting, mortality and interpopulational growth comparisons. The aims were to analyze the spatial distribution from surveys data, population structure, growth and mortality of several beds along a latitudinal gradient based on age determination by thin sections of valves. We also describe the spatial fishing effort allocation of the fleet, and its sources of variability collecting data on board. Three geoducks beds were located and sampled along the coast: El Sótano, Punta Colorada, and Puerto Lobos. Geoducks age ranged between 2 to 86 years. Growth pattern showed significative difference in asymptotic size among El Sótano (109.4 mm) and Puerto Lobos (98.06 mm). Maximum age showed a North-South decreasing trend. Natural mortality was estimated in each bed by catch curve (M = 0.105 ? 0.177 yr -1), a method based in mean age (M = 0.212?0.233 yr-1) and a method based in maximum longevity recorded (M = 0.062 ? 0.13 yr-1). Geoduck supports a diving harvest at El Sótano. The population features were integrated at harvest analysis of divers into a preliminary management proposal that include subdivision of coastal zone, limited entry, harvest rate and individual vessel quotas.