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OEG was supported by MASTS (the Marine Alliance for Science and Technology for Scotland). Accurately estimating patterns of population connectivity in marine systems remains an elusive goal. Current genetic approaches have focused on assigning individuals back to their natal populations using one of two methods: parentage analyses and assignment tests. Each of these approaches has their relative merits and weaknesses. Here, we illustrate these tradeoffs using a forward-time agent-based model that incorporates relevant natural history and physical oceanography for 135 Kellet’s whelk (Kelletia kelletii) populations from Southern California. Like most marine organisms, Kellet’s whelks live in large metapopulations where local populations are connected by dispersive larvae. For estimating population connectivity, we found parentage analyses to be relatively insensitive to the amount of genetic differentiation among local populations, but highly sensitive to the proportion of the metapopulation sampled. Assignment tests, on the other hand, were relatively insensitive to the proportion of the metapopulation sampled, but highly sensitive to the amount of genetic differentiation found among local populations. Comparisons between the true connectivity matrices (generated by using the true origin of all sampled individuals) and those obtained via parentage analyses and assignment tests reveal that neither approach can explain more than 26% of the variation in true connectivity. Furthermore, even with perfect assignment of all sampled individuals, sampling error alone can introduce noise into the estimated population connectivity matrix. Future work should aim to improve the number of correct assignments without the expense of additional incorrect assignments, perhaps by using dispersal information gleaned from related individuals as priors in a Bayesian framework. These analyses dispel a number of common misconceptions in the field and highlight areas for both future research and methodological improvements. Postprint

Documenting larval behavior is critical for building an understanding of larval dispersal dynamics and resultant population connectivity. Nocturnal diel vertical migration (DVM), a daily migration towards the surface of the water column at night and downward during the day, can profoundly influence dispersal outcomes. Via laboratory experiments we investigated whether marine gastropodKelletia kelletiilarvae undergo nocturnal DVM and whether the behavior was influenced by the presence of light, ontogeny, and laboratory culturing column height. Larvae exhibited a daily migration pattern consistent with nocturnal diel vertical migration with lower average vertical positioning (ZCM) during day-time hours and higher vertical positioning at night-time hours. ZCM patterns varied throughout ontogeny; larvae became more demersal as they approached competency. There was no effect of column height on larval ZCM. DVM behavior persisted in the absence of light, indicating a possible endogenous rhythm. Findings from field plankton tows corroborated laboratory nocturnal DVM findings; significantly moreK.kelletiiwere found in surface waters at midnight compared to at noon. Unraveling the timing of and the cues initiating DVM behavior inK.kelletiilarvae can help build predictive models of dispersal outcomes for this emerging fishery species.

California’s Marine Life Management Act is a broad piece of legislation that mandates California’s living marine resources be managed with a goal of long-term sustainability. The Act went into effect in 1999, since which time the Fish and Game Commission and the Department of Fish and Game have satisfied a number of explicitly required elements. These include completion of Status of the Fisheries Report, a Master Plan that prioritizes fisheries for future management, and fishery management plans (FMPs) for several species. Discussions are underway for assessments and/or management for a few other species. However, due to lack of adequate financial and personnel resources, well-defined deadlines or repercussions, momentum has slowed on implementing the intended wide-ranging management for all species. Specific elements that have not been adequately addressed include: emerging fisheries, recreational fisheries, and managing data-poor fisheries (applicable to the first two). This paper explores some simple tools for evaluating and managing data-poor fisheries. Kellet’s whelk is examined as a possible emerging fishery, and barred sand bass and kelp bass are considered together as important components of the recreational fishery. The findings indicate that simple assessments are possible with available data, interim management is essential for emerging fisheries and spatial scale is important for management considerations.