Aspects of reproductive biology of the geoduck clam Panopea globosa (Dall 1898) in the Gulf of California

Abstract

This paper describes basic aspect of reproductive biology of the geoduck clam Panopea globosa from a population in the east central Gulf of California. Geoduck clams were collected monthly for a year (October 2004-October 2005), The gonadosomatic index and ovocyte growing (oocyte diameters) techniques were used to determine the spawning timing. Reproductive period was related with in situ temperature and seawater surface temperatures (SST) from the Comprehensive Oceanic and Atmospheric Data Set. Reproduction phases were similar to other geoduck clams in New Zealand and Canada. Gametogenesis begins in autumn and spawning occurred between January and February winter), when SST were at their coolest (~18 oC). We found that P. globosa spawned at comparable temperatures as P. zelandica in the southern hemisphere, but the reproductive strategy of the California geoduck clam seemed closer to P. abrupta of the northern hemisphere because spawning occurred in association with increased seawater temperature. Results represent the basis for future studies on the biology, ecology, and fishing potential of this geoduck clam.