2 resultados para Astyanax bimaculatus species complex

em DigitalCommons - The University of Maine Research


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Hyalella azteca is a species complex distributed in North, Central, and northern South America. The identity of the species has always been a problem, especially because the original description by Saussure (1858) from a "cistern" in Vera Cruz, Mexico, is poor, and the figures are not clear. Since then, mention of the type material or specimens from the type locality has not been made by investigators using the name H. azteca. Ecological and genetic information available today suggests that there are several species in the complex commonly referred to as H. azteca. The subtle morphological differences among the populations have made the problem of defining these species very complicated. To aid in this process, we present here the morphological description of H. azteca based on the syntype series established by Saussure and deposited in the Museum d'Histoire Naturelle, Ville de Geneve, Switzerland.

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This paper considers ocean fisheries as complex adaptive systems and addresses the question of how human institutions might be best matched to their structure and function. Ocean ecosystems operate at multiple scales, but the management of fisheries tends to be aimed at a single species considered at a single broad scale. The paper argues that this mismatch of ecological and management scale makes it difficult to address the fine-scale aspects of ocean ecosystems, and leads to fishing rights and strategies that tend to erode the underlying structure of populations and the system itself. A successful transition to ecosystem-based management will require institutions better able to economize on the acquisition of feedback about the impact of human activities. This is likely to be achieved by multiscale institutions whose organization mirrors the spatial organization of the ecosystem and whose communications occur through a polycentric network. Better feedback will allow the exploration of fine-scale science and the employment of fine-scale fishing restraints, better adapted to the behavior of fish and habitat. The scale and scope of individual fishing rights also needs to be congruent with the spatial structure of the ecosystem. Place-based rights can be expected to create a longer private planning horizon as well as stronger incentives for the private and public acquisition of system relevant knowledge.