Historical Reconstruction of Biomass of Panopea globosa from the Southwestern Coast of Baja California Peninsula, Mexico: A New Perspective for Geoduck Fishery Management

Abstract

In this study, fishery-independent data were used to analyze changes in average density and biomass of Panopea globosa between 2007 and 2018. Different statistical estimators based on the probabilistic density function, such as Gaussian and generalized distributions, were used, all of them associated with the spatial patchy distribution of the geoduck clam. Both average density and biomass showed a dramatic decline throughout the study period, decreasing from 31 geoducks/50 m2 (2007) to 10 geoducks/50 m2 (2018) and from 126,000 to 35,000 t, respectively. In addition, a high harvest of individuals greater than 175 mm of shell length was observed, increasing the possibility of recruitment overfishing. Finally, a Kobe phase chart applied to P. globosa fishery in Bahía Magdalena showed that the stock status was identified as overfished.