What are the prospects for black bream Acanthopagrus butcheri (Munro) aquaculture in salt‐affected inland Australia?

Black bream are a highly regarded sport and table fish, and there has been considerable interest in their aquaculture potential for the salt‐affected agricultural regions of inland southern Australia. In many ways they are an ideal candidate species for inland saline aquaculture because they appear to be very hardy, hatchery techniques are well established for them, and high survival rates have been maintained under a variety of culture conditions and feeding regimes. However, their slow growth rate needs to be increased by at least 33% for black bream to become an economically viable aquaculture species. Growth is amenable to genetic improvement, and sub‐adult growth rate shows moderate heritability and no adverse genetic correlations with other production traits. Nevertheless fillet yield is comparatively low, and in conjunction with unpredictable and early sexual development in culture, industry‐scale meat production remains problematic. These obstacles, however, do not preclude the use of black bream as a recreational fish species for inland saline waters, where their stocking may provide an additional source of rural income and relieve fishing pressure on depleted estuarine populations.     

Growth, Survival and Reproductive Performance of Domesticated Australian Stocks of the Giant Tiger Prawn, Penaeus monodon, Reared in Tanks and Raceways

The growth, survival and reproductive performance of domesticated Australian stocks of the giant tiger shrimp Penaeus monodon were evaluated in trials conducted in 1997 and 2003. The 1997 trials assessed the performance of first generation progeny of wild broodstock from the northeast coast of Australia and fourth generation progeny of pond‐reared broodstock, which also originated from northeast coast wild stocks. In these trials, growth and survival of the shrimp were assessed when reared for 17 mo in tanks. Reproductive performance of the shrimp was assessed at 14.5 mo and 17 mo. The 2003 trials assessed the performance of first generation progeny of wild broodstock from the Gulf of Carpentaria (north coast of Australia). In these trials, growth and survival of shrimp were assessed when reared for 14 mo in tanks and raceways. Reproductive performance of the shrimp was assessed at 11 mo, 12 mo, and 15 mo. Growth and reproductive performance of the stocks varied between trials, families, ages and rearing systems. The most pronounced differences in growth and reproductive performance were between the 1997 and 2003 trials. At 11 mo of age, the average wet weight of the shrimp in the 2003 trials (females 117.1 ± 5.8 g; males 87.9 ± 7.6 g) was 200% greater than the average wet weight of shrimp in the 1997 trials (females 55.2 ± 6.8 g; males 41.2 ± 3.4 g). The reproductive performance of the shrimp was also higher in the 2003 trials in terms of the percentage of spawnings hatching (52.0% in 1997; 77.1% in 2003) and mean hatch rate (21.5% in 1997; 31.6% in 2003). Differences in the growth and reproductive performance of the tank‐reared stocks between years were indicative of significant improvements in the rearing environment, diet and husbandry techniques. Variation in the reproductive performance between families was consistent across rearing environments and at different ages and suggests the potential to improve reproductive performance through genetic selection. Notably, this study identified hatch rates of nauplii from the spawned eggs as a key area for future improvement of domesticated stocks reared in tanks and raceways. Future efforts to improve the growth and reproductive performance of domesticated P. monodon could benefit from integrating incremental improvements to husbandry with genetic selection.     

The effects of landscape composition and physiognomy on metapopulation size: the role of corridors

We develop and analyze a model that examines the effects of corridor quality, quantity, and arrangement on metapopulation sizes. These ideas were formerly investigated by Lefkovitch and Fahrig (1985) and Henein and Merriam (1990). Our simulations provide results similar to the Henein and Merriam model, indicating that the quality of corridors in a landscape and their arrangement will influence the size of a metapopulation. We then go one step further, describing how corridor arrangement alters the metapopulation, and provide a method for predicting which corridor arrangements should support larger metapopulations. In contrast to the Henein and Merriam model, we find that the number of corridor connections has no influence on the size of a metapopulation in a landscape unless there is an accompanying change in the uniformity of the distribution of corridor connections among patches.     

Use of the pisces database: Power plant aqueous stream compositions

The Power Plant Integrated Systems: Chemical Emissions Studies (PISCES) Database sponsored by the Electric Power Research Institute is a powerful tool for evaluating and comparing the level of trace substances in power plant process streams. In this paper, data are presented on the level of several selected trace metals found in a few of the aqueous streams present in power plants. In addition, a brief discussion of other features of the Database is presented.     

Mutational analysis of the tyrosine phosphatome in colorectal cancers

Tyrosine phosphorylation, regulated by protein tyrosine phosphatases (PTPs) and kinases (PTKs), is important in signaling pathways underlying tumorigenesis. A mutational analysis of the tyrosine phosphatase gene superfamily in human cancers identified 83 somatic mutations in six PTPs (PTPRF, PTPRG, PTPRT, PTPN3, PTPN13, PTPN14), affecting 26% of colorectal cancers and a smaller fraction of lung, breast, and gastric cancers. Fifteen mutations were nonsense, frameshift, or splice-site alterations predicted to result in truncated proteins lacking phosphatase activity. Five missense mutations in the most commonly altered PTP (PTPRT) were biochemically examined and found to reduce phosphatase activity. Expression of wild-type but not a mutant PTPRT in human cancer cells inhibited cell growth. These observations suggest that the mutated tyrosine phosphatases are tumor suppressor genes, regulating cellular pathways that may be amenable to therapeutic intervention.