Evaluating adult aggregations of Northern abalone (Haliotis kamtschatkana) for restoration in the Puget Sound, Washington
W. A. Bennett, University of California, Davis, $34,987

Northern abalone stocks are critically depleted throughout much of their range yet restoration strategies methods remain largely untested. One promising technique is the aggregation of adults to promote successful larval production. Aggregating adults may overcome the problems faced by many free spawning marine invertebrates when their densities decline and males and females are spread apart hindering fertilization: Allee Effects. Stocking larval and juvenile abalone reared in captivity is another restoration method that has been used, however restoration results appear to be mixed and highly spatially variable. Furthermore, disease issues can complicate stocking strategies. Here we propose using a programmatic approach to implementing adult aggregation as part of a larger northern abalone restoration strategy. First, population models of northern abalone will be used to examine the size of adults needed in the aggregation restoration program. Second, aggregation experiments will be deployed within sites in the San Juan Islands using information gained from previous field work. Third, aggregation sites will be compared with control sites using a BACI (Before After Control Impact) experimental design. Finally, new methods for assessing newly settled abalone in the field will be used to quantify the impacts of the aggregation experiments and evaluate any potential bottlenecks which may hinder or promote the efficacy of the aggregation restoration strategy. Recruitment failure can occur at multiple life history stages including the larval, newly settled and juvenile abalone stages creating bottlenecks for the successful restoration of northern abalone. Evaluating the success or failure of the aggregating adults will require a comprehensive approach including identification of critical stages in recruitment, attention to experimental design, knowledge gained from population modeling and quantitative evaluation of this restoration action.