C. Friedman, University of Washington: $34,998
The efficacy of aggregation as an in-situ restoration technique for the recovery of pinto abalone (Haliotis kamtschatkana) in the San Juan Archipelago
Populations of pinto (northern) abalone, native to the Puget Sound Georgia Basin, have declined significantly over the past 15 years, with very little recruitment of juvenile and young adults. Our working hypothesis is that the lack of recruitment is the direct result of low adult abundance and overall density; since abalone broadcast their gametes into the water column, fertilization can only take place if abalone are relatively close together in an aggregation. We will establish two experimental aggregations of wild pinto abalone, one made up of 20-30 lone wild individuals, and the other from a similar number of health-screened individuals that have been held as broodstock in our NOAA restoration hatchery facility, to elucidate differences in survival, movement, and aggregation persistence. As the ultimate goal of this work is to increase reproductive success, in year 2 of the grant we will exhaustively survey the aggregation sites for juveniles. Those found will be genotyped to determine whether they are likely to be progeny of aggregated individuals, since recruitment is thought to be localized. If supplementation program broodstock and wild abalone exhibit high survival and their aggregation behavior proves similar, we may adapt our restoration approach to include annual procurement of lone wild individuals for supplementation program broodstock and subsequent aggregation to increase future chances of successful reproduction in the wild.
W. A. Bennett, University of California, Davis, $34,987
Evaluating adult aggregations of Northern abalone (Haliotis kamtschatkana) for restoration in the Puget Sound, Washington
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.
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