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A survey of 16 enzyme systems and two structural proteins, among nine eastern oyster (Crassostrea virginica) populations in and adjacent to Laguna Madre, Texas, identified two genetically differentiated groups and the transition zone between them. The discontinuity in allele frequencies occurred between a reef in Corpus Christi Bay and reefs 26 km away in upper Laguna Madre. Although no fixed allelic differences were observed between populations from either side of the transition area, substantial frequency differences were observed at six gene loci, and both groups exhibited unique alleles. Spatial heterogeneity tests also suggested sizable allele frequency differences, as 8 of 15 polymorphic loci surveyed exhibited heterogeneity. Considerable genetic subdivision was observed, as 14 of 15 polymorphic loci surveyed exhibited significant fixation indices. The mean genetic similarity was 0.898 (range 0.813–0.977). Consequently, oysters inhabiting the Laguna Madre are genetically divergent from oysters inhabiting central and eastern Texas, the north-central and eastern Gulf of Mexico, and the western Atlantic coast. Thus, these groups should be considered as discrete management units, and the patterns of genetic exchange investigated. If eastern oysters inhabiting the Laguna Madre, Texas, are unique, they warrant protection.

Ocelots (Leopardus pardalis) are listed as endangered federally and by the state of Texas. Preference for closed canopy habitat has been shown in previous studies, but preference for patch size has not been reported. Geographic Information Systems (GIS) and satellite imagery were used to compare areas in south Texas used by radio-collared ocelots to areas with no known use. We hypothesized that ocelots would prefer large patches of closed canopy habitat and avoid large patches of unsuitable habitat. Areas used by ocelots had a greater degree of fragmentation (i.e., larger number of patches, smaller size, and more edge) than did those not used. Further investigation revealed that ocelots preferred patches of closed canopy over other types of land cover and that this land cover type exhibited a greater degree of fragmentation. Results of this study were used to designate areas for conservation of ocelot habitat and can be applied to the management of other threatened or endangered wildlife. JOURNAL OF WILDLIFE MANAGEMENT 69(2):733-738; 2005

1991. Tissue-specific patterns of synthesis of heat-shock proteins and thermal tolerance of the fathead minnow (Pimephales promelas). Can. J. Zool. 69: 2021-2027. Qualitative and quantitative differences in the heat-shock response in brain, gill, and striated muscle tissues of the fathead minnow (Pimephales promelas) were investigated. The maximum sublethal heat-shock temperature was 34°C. The heat-shock proteins (hsps) induced, their biosynthetic rates, minimum temperatures required for induction, and maximum temperatures at which each tissue synthesized hsps were tissue specific. Six hsps were induced in gill tissue (100,90,78,70,68, and 60 kDa), four in muscle tissue (100,90,78, and 70 m a ) , and three in brain tissue (90,70, and 68 m a ) . Minimum temperatures required for inducing the stress response in gill, muscle, and brain were 28, 31, and 32"C, respectively. Maximum hsp synthesis and accumulation occurred at 33°C for the brain and 34°C for muscle and gill. Synthesis and accumulation of hsps decreased to near pre-exposure levels in the brain at 34°C. The fact that brain tissue synthesized the fewest hsps and had the lowest capacity for synthesis at the upper thermal limits of the organism supports the hypothesis that the central nervous system governs the thermal limits to survival in poikilotherms. DYER, S. D., DICKSON, K. Lr, ZIMMERMAN, E. G., et SANDERS, B. M. 1991. Tissue-specific patterns of synthesis of heat-shock proteins and thermal tolerance of the fathead minnow (Pimephales promelas). Can. J. Zool. 69 : 2021-2027. Les diffdrences qualitatives et quantitatives de la rkaction protkinique aux chocs t e~i q u e s ont Ct C mesurCes dans le cerveau, les branchies et les muscles striCs chez le T2te-de-boule (Pimephales promelas). La tempkrature de choc sublCtale supkrieure a Ct C CvaluCe A 34°C. Les protCines de choc spicifiques (hsp) synthCtisCes, leur taux de biosynthkse, les tempCratures minimales nCcessaires A la synthkse, et les tempkratures maximales auxquelles chaque tissu synthCtisait les hsp Ctaient spCcifiques A chaque tissu. Six de ces protCines ont Ct C synthCtisCes dans les branchies (100,90, 78,70,68 et 60 m a ) , quatre dans les muscles (100, 90,78 et 70 kDa) et trois dans le cerveau (90,70 et 68 m a ) . Les tempkratures minimales requises pour provoquer un stress ont Ct C estimCes A 28°C dans le cas des branchies, 3 1°C dans le cas des muscles et 32°C dans le cas du cerveau. C'est A 33°C dans le cerveau et A 34°C dans les muscles et les branchies que se sont produites la synthkse la plus active et l'accumulation maximale des protCines. A 34"C, la synthkse et l'accumulation des protCines sont retombCes A des valeurs voisines des valeurs enregistrdes avant le choc dans le cerveau. Le fait que le tissue du cerveau synthCtise le moins grand nombre de protkines de choc therrnique et qu'il ait la plus faible capacitC de synthdtisation aux limites lCtales supCrieures de l'organisme semble indiquer que c'est le systkme nerveux central qui fixe les seuils thermiques de survie chez les,poikilot...

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