The Galapagos Grouper Fishery: Mostly Dead, Stunned, or In Need of Management Regulations?

Abstract

Ph.D. University of Hawaii at Manoa 2015.Includes bibliographical references.The Galapagos sailfin grouper Mycteroperca olfax, locally known as bacalao, is an important ecological, cultural, and economical resource in the Galapagos Archipelago. However, years of intensive fishing pressure have resulted clear signs of overfishing. Bacalao represent an important resource for which there is no management, but for which management cannot be implemented because of a lack of information on the current status of the fishery and inconsistencies in life history information. My research was, therefore, aimed at assessing life history and fisheries attributes for bacalao with the goal of providing management options for this species. Longevity of bacalao is greater than previously reported, with a maximum recorded age of 21 years. Growth estimates showed bacalao to grow larger and slower than previously thought. Size at maturity was also estimated to be larger than previously accepted assessments. Current status of the bacalao fishery is worrisome as it is undergoing both recruitment and growth overfishing. The percentage of fish above size at maturity in the catch has dropped to an all time low, and Spawning Potential Ratio suggests that bacalao is facing imminent reproductive failure. Furthermore, over a 20-­‐‑year period there have been declines in all of the stock health indicators, with 2012 being the lowest year on record. In lieu of management regulations specifically aimed at bacalao, the Galapagos Marine Reserve relies on no-­‐‑take zones to provide protection from fishing. However, size of bacalao, catch rates, and catch composition were indistinguishable between areas open and closed to fishing. Bacalao showed high site fidelity and likely do not move outside no-­‐‑take zones, and therefore poaching within these zones may contribute to the patterns observed. An evaluation of the knowledge of fishers of the current GMR zonation suggests that this lack of compliance due to unwitting poaching. My research has provided valuable information upon which management regulations for bacalao can be built, these should include slot limits, temporal closures, and adequate enforcement of no fishing areas