Genetic diversity in wild stocks of the giant freshwater prawn (Macrobrachium rosenbergii): implications for aquaculture and conservation

The giant freshwater prawn (Macrobrachium rosenbergii) is cultured widely around the world but little is known about the levels and patterns of genetic diversity in either wild or cultured stocks. Studies have suggested that genetic diversity may be relatively low in some cultured stocks due to the history of how they were founded and subsequent exposure to repeated population bottlenecks in hatcheries. In contrast, wild stocks have an extensive distribution that extends from Southern Asia across Southeast (SE) Asia to the Pacific region. Therefore, wild stocks could be an important resource for genetic improvement of culture stocks in the future. Understanding the extent and patterns of genetic diversity in wild giant freshwater prawn stocks will assist decisions about the direction future breeding programs may take. Wild stock genetic diversity was examined using a 472 base-pair segment of the 16S rRNA gene in 18 wild populations collected from across the natural range of the species. Two major clades ("eastern" and "western") were identifi ed either side of Huxley’s line, with a minimum divergence of 6.2 per cent, which implies separation since the Miocene period (5-10 MYA). While divergence estimates within major clades was small (maximum 0.9 per cent), evidence was also found for population structuring at a lower spatial scale. This will be examined more intensively with a faster evolving mtDNA gene in the future.

Length-weight relationships of five species of the family Sparidae in the Gulf of Guinea

Length-weight relationships are presented by sex and by country for five species of the family Sparidae (Pugrus caeruleostictus, Pagellus bellottii, Dentex canariensis, Dentex congonensis, Dentex angolensis) sampled in April 1990 during the Guinea '90 trawling survey off Sierra Leone, Liberia, Cote d'Ivoire and Ghana.

Comparative growth performance for species of the Family Clupeidae of Sierra Leone

Using length-frequency samples from the local fisheries and length-age data from otolith readings, von Bertalanffy growth parameters were estimated for the four species representing the Clupeidae family in Sierra Leone, Sardinella aurita, S. maderensis, Ethmalosa fimbriata and Ilisha africana showed the highest and lowest values of f, respectively, while Sardinella sp. were found to occupy the central position.

O pragmatismo antiteórico de Richard A. Posner e as respostas da teoria moral para a decisão judicial

Este trabalho apresenta uma análise crítica à forma de se abordar casos jurídicos e proferir decisões judiciais denominada abordagem judicial pragmática, disseminada pelo magistrado e professor norte-americano Richard A. Posner. O objetivo é explicitar suas principais características e contornos, bem como sua repulsa pela teorização abstrata e pelos debates e argumentos morais na decisão judicial. A partir disso, pretende-se refutar parte dessa abordagem pragmática, por meio de argumentos levantados por filósofos morais e profissionais do direito a saber: Ronald Dworkin, Charles Fried, Anthony Kronman, John T. Noonan Jr e Martha C. Nussbaum - em defesa de uma abordagem que prega a inevitável utilização do raciocínio teórico, assim como a argumentação e reflexão moral na resolução de casos difíceis relacionados ao direito. Também será destacado como a repulsa pragmática pela teoria moral e abstrata é incompatível com a conjuntura justeórica contemporânea e como a análise de alguns casos difíceis expõe a falibilidade, ainda que parcial, desse estilo de abordagem pregado por Posner.