Granados-Dieseldorff, Pablo (2013-12). The Mutton Snapper (Lutjanus analis) Spawning Aggregation Fishery at Gladden Spit, Belize: Inter-annual and Within-season Dynamics. Doctoral Dissertation. Thesis uri icon


  • Artisanal fisheries constitute a considerable source of employment, income, and protein for many coastal communities in the Caribbean. One of the region's most valuable fisheries is for mutton snapper (Lutjanus analis), a coral-reef fish that uses various habitats throughout its life cycle, aggregates to spawn at specific places and times, and is considered vulnerable to extinction. This dissertation focuses on the mutton snapper spawning aggregation fishery at Gladden Spit, Belize (western Caribbean), which has existed since the 1950s. In 2000, the Government of Belize partnered with a community-based nongovernment organization, fishers, and other stakeholders to conserve and co-manage the artisanal fishery. Considering the study fishery as an adaptive socio-environmental fisher-fish system, this dissertation uses a holistic approach to provide baseline socioeconomic and biological information for strengthening conservation and management of mutton snapper fisheries in Belize, applicable to the rest of the Caribbean. The three overall goals of this dissertation were to 1) present the history of the fishery and delineate for the first time its socio-environmental development and impact on inter-annual catch dynamics and yields, using published and grey literature, knowledge of experienced fishers and stakeholders, and data from landings surveys; 2) characterize the fishery's within-season dynamics in 2011 through analyses of the variability in fishing activity, catch and bycatch, and in size, age, and maturation of reproductive mutton snapper, and 3) evaluate the potential distribution of habitat for early life stages of mutton snapper across the Belize shelf, using a GIS-based multi-criteria modeling approach evaluated in the field. Inter-annual analyses evidenced a considerable reduction in total landings and fishing effort of the fishery in the late 1980s, parallel to a rapid growth in the tourism industry and to a shift in the livelihoods of many local fishers. Between 1999 and 2011, during the co-management period of the fishery, relatively stable values of annual catch per unit effort (CPUE), individual sizes, and sex ratios suggested persistence of the fishery. Otolith, size, and gonad analyses depicted, for the first time for the species, age-, size-, and maturation-structured mutton snapper spawning aggregations. Within-season analyses showed how mutton snapper size, age, and degree of maturation vary in relation to the lunar cycle and throughout the spawning season, with individuals significantly smaller and females mostly immature later in the season. Overall, the within-season dynamics of the fishery were influenced by the lunar and seasonal patterns in the reproductive biology of mutton snapper, interactions with co-occurring fisheries, and the experience and traditions of local fishers. The GIS-based model provided a common spatial framework for guiding conservation and spatial management of mutton snapper in Belize and highlighted a low degree of protection currently afforded to critical juvenile habitats constituted of mangroves and seagrass from coastal and shelf regions.

publication date

  • December 2013