Size-related Hooking Mortality of Incidentally Caught Chinook Salmon, Oncorhynchus tshawytscha

Mortality associated with the incidental catch and release by commercial trollers of two size classes of chinook salmon, Oncorhynchus tshawytscha, was assessed. Observed cumulative mortality 4-6 days after hooking was 18.3 percent for sublegal-sizefish « 66 cm FL) and 19.0 percent for legal-sizefish. Size of fish was not significantly related to mortality; however, when the results were combined with data from a previous experiment, there was a significant inverse relationship between fish length and mortality. Hooking mortality estimates calculated from tagging experiments and observed relative mortality of legal-and sublegal-size fish held in net pens, were used to derive a range for total hooking mortality of 22.0-26.4 percent for sublegal-size chinook salmon and 18.5-26.4 percent for legal-size chinook salmon.

The Effects of Fish Trap Mesh Size on Reef Fish Catch off Southeastern Florida

Catch and mesh selectivity of wire-meshed fish traps were tested for eleven different mesh sizes ranging from 13 X 13 mm (0.5 x 0.5") to 76 x 152 mm (3 X 6"). A total of 1,810 fish (757 kg) representing 85 species and 28 families were captured during 330 trap hauls off southeastern Florida from December 1986 to July 1988. Mesh size significantly affected catches. The 1.5" hexagonal mesh caught the most fish by number, weight, and value. Catches tended to decline as meshes got smaller or larger. Individual fish size increased with larger meshes. Laboratory mesh retention experiments showed relationships between mesh shape and size and individual retention for snapper (Lutjanidae), grouper (Serranidae), jack (Carangidae), porgy (Sparidae), and surgeonfish (Acanthuridae). These relationships may be used to predict the effect of mesh sizes on catch rates. Because mesh size and shape greatly influenced catchability, regulating mesh size may provide a useful basis for managing the commercial trap fishery.

Sucessos de governo no Brasil: habilidades ou instituições?

A literatura sobre presidencialismo na Ciência Política se encontra bastante consolidada, no entanto, ainda existem dúvidas sobre os fatores que mais influenciam os presidentes em ter seus projetos aprovados. Visando contribuir para esta literatura, este trabalho examina a aprovação de leis do Executivo no Brasil, observando o efeito das prerrogativas presidenciais, tipos de matérias legislativas e contextos políticos. Os resultados encontrados apontam que as prerrogativas exclusivas tais como medidas provisórias, encurtando o tempo de apreciação das leis no Congresso e matérias exclusivas (administrativas e orçamentárias) além das econômicas devido à vantagens informacionais do Executivo sobre o Congresso em razão de instituições como Banco Central e Ministério da Fazenda possuem influência positiva na aprovação das leis do Executivo. Além disso, o sucesso do governo é potencializado durante o período de "honeymoon" e tem variação positiva significativa em quanto maior for a coalizão de governo. Todavia, os resultados mostram que a "habilidade" não impacta significativamente no sucesso e popularidade inesperadamente possui efeito negativo.