Browsing by Author "White, Crow"

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    Anticipating trade-offs and promoting synergies between small-scale fisheries and aquaculture to improve social, economic, and ecological outcomes
    (2024) Mansfield, Elizabeth J.; Micheli, Fiorenza; Fujita, Rod; Fulton, Elizabeth A.; Gelcich Crossley, Stefan; Battista, Willow; Bustamante, Rodrigo H.; Cao, Ling; Daniels, Benjamin N.; Finkbeiner, Elena M.; Gaines, Steven; Peckham, Hoyt; Roche, Kelly; Ruckelshaus, Mary; Salomon, Anne K.; Sumaila, U. Rashid; White, Crow; Naylor,Rosamond
    Blue food systems are crucial for meeting global social and environmental goals. Both small-scale marine fisheries (SSFs) and aquaculture contribute to these goals, with SSFs supporting hundreds of millions of people and aquaculture currently expanding in the marine environment. Here we examine the interactions between SSFs and aquaculture, and the possible combined benefits and trade-offs of these interactions, along three pathways: (1) resource access and rights allocation; (2) markets and supply chains; and (3) exposure to and management of risks. Analysis of 46 diverse case studies showcase positive and negative interaction outcomes, often through competition for space or in the marketplace, which are context-dependent and determined by multiple factors, as further corroborated by qualitative modeling. Results of our mixed methods approach underscore the need to anticipate and manage interactions between SSFs and aquaculture deliberately to avoid negative socio-economic and environmental outcomes, promote synergies to enhance food production and other benefits, and ensure equitable benefit distribution.
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    Phylogeography of the California sheephead, Semicossyphus pulcher: the role of deep reefs as stepping stones and pathways to antitropicality
    (2013) Poortvliet, Marloes; Longo, Gary C.; Selkoe, Kimberly; Barber, Paul H.; White, Crow; Caselle, Jennifer E.; Perez-Matus, Alejandro; Gaines, Steven D.; Bernardi, Giacomo
    In the past decade, the study of dispersal of marine organisms has shifted from focusing predominantly on the larval stage to a recent interest in adult movement. Antitropical distributions provide a unique system to assess vagility and dispersal. In this study, we have focused on an antitropical wrasse genus, Semicossyphus, which includes the California sheephead, S.pulcher, and Darwin's sheephead, S.darwini. Using a phylogenetic approach based on mitochondrial and nuclear markers, and a population genetic approach based on mitochondrial control region sequences and 10 microsatellite loci, we compared the phylogenetic relationships of these two species, as well as the population genetic characteristics within S.pulcher. While S.pulcher and S.darwini are found in the temperate eastern Pacific regions of the northern and southern hemispheres, respectively, their genetic divergence was very small (estimated to have occurred between 200 and 600 kya). Within S.pulcher, genetic structuring was generally weak, especially along mainland California, but showed weak differentiation between Sea of Cortez and California, and between mainland California and Channel Islands. We highlight the congruence of weak genetic differentiation both within and between species and discuss possible causes for maintenance of high gene flow. In particular, we argue that deep and cooler water refugia are used as stepping stones to connect distant populations, resulting in low levels of genetic differentiation.