UPRSG final report
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Executive Summary Project title: An interdisciplinary evaluation of the fishery for Cittarium pica Date: April 24, 2015 Project Number: R-32-1-12 Investigators and affiliation: Graham Forrester [PI] Department of Natural Resources Science, University of Rhode Island Carlos García-Quijano [Co-PI] Department of Sociology and Anthropology, University of Rhode Island Dates Covered: Start: 02/01/2012 End: 01/31/2015 Summary of Impacts and Contributions: Objectives: Objective 1. We isolated the impact of fishing on C. pica populations by correlating C. pica abundance and size-distributions to levels of access to fishers. C. pica populations subject to chronic harvesting have a much smaller fraction of adult-sized and legal-sized whelks than sites that are not regularly accessed by fishers. Effects on population density are less clear-cut, but appear to be affected by both wave exposure and harvesting. Objective 2. We assessed the biological effectiveness of size-limits, catch limits and seasonal closures. Recruitment occurs year round, so seasonal closures should not affect reproduction. Despite rapid growth rates, a mark-recapture study showed that immature whelks dominate many populations so size-limits are not having the effect of protecting reproductive adults. Objective 3. We assessed coastal harvesters’ and their community’s dependence on C. pica. Long-time fishers report declining catches, which has led to many moving away from the fishery. Currently, fishers are secretive about good collecting sites and most target C. pica sporadically to supplement their income. This supplementary income can be important for the livelihood resilience of these fishers, as C. pica is marketed as a luxury seafood item with relatively high monetary returns for effort. There is a complex, relatively informal network of distribution and sale of C. pica in coastal communities. Value derived from C. pica catches may go unnoticed by official income assessments. Objective 4. We assessed the social effectiveness of alternate management strategies by understanding patterns of harvesting C. pica and the receptiveness of fishers to alternate management actions. Commercial C. pica fishers are knowledgeable about the fishery, fishing regulations, and generally concerned with the future of the fishery. Recreational/subsistence fishers, in contrast, are generally unaware of, and sometimes violate, regulations. There was some support among regular fishers for reserves, if there was community involvement in management. Advancement of the Field: Like many small-scale fisheries, the fishery for C. pica targets a sedentary coastal species, has been largely ignored by fisheries scientists, and is not amenable to traditional stock assessment as a way of understanding the effects of fishing. Our alternate ecological field approach, was successful at revealing a clear contemporary impact of fishing, and our archaeological analysis showed that impacts of fishing in Puerto Rico extend back hundreds of years, perhaps even before European settlement, whereas there was less evidence of a long-term impact on a small-