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Pacific trout Oncorhynchus spp. in western North America are strongly valued in ecological, socioeconomic, and cultural views, and have been the subject of substantial research and conservation efforts. Despite this, the understanding of their evolutionary histories, overall diversity, and challenges to their conservation is incomplete. We review the state of knowledge on these important issues, focusing on Pacific trout in the genus Oncorhynchus. Although most research on salmonid fishes emphasizes Pacific salmon, we focus on Pacific trout because they share a common evolutionary history, and many taxa in western North America have not been formally described, particularly in the southern extent of their ranges. Research in recent decades has led to the revision of many hypotheses concerning the origin and diversification of Pacific trout throughout their range. Although there has been significant success at addressing past threats to Pacific trout, contemporary and future threats represented by nonnative species, land and water use activities, and climate change pose challenges and uncertainties. Ultimately, conservation of Pacific trout depends on how well these issues are understood and addressed, and on solutions that allow these species to coexist with a growing scope of human influences. Conservación de la diversidad de truchas nativas del Pacífico en el oeste de NorteaméricaLa trucha del Pacífico Oncorhynchus spp. en el oeste de Norteamérica tiene un alto valor desde el punto de vista ecológi-co, socioeconómico y cultural, y ha sido objeto de importantes esfuerzos de conservación e investigación. A pesar de ello, el conocimiento que se tiene sobre su historia evolutiva, diversidad general y retos de conservación sigue siendo incompleto. Se hace una revisión del estado del conocimiento sobre estos puntos, con énfasis en la trucha del Pacífico dentro del género Oncorhynchus. Si bien la mayor parte de los estudios hechos sobre salmónidos se enfocan al salmón del Pací-fico, aquí nos enfocamos en la trucha del Pacífico ya que ambos groupos de especies comparten una historia evolutiva en común sobre todo en lo que se refiere al extremo sur de sus rangos de distribución. En investigaciones llevadas a cabo en décadas recientes, se han revisado varias hipótesis relativas al origen y diversificación de la trucha del Pacífico a lo largo de su rango de distribución. Aunque se han logrado identificar adecuadamente las amenazas pasadas que enfrentó la trucha del Pacífico, las amenazas actuales y futuras que representan especies no nativas, actividades de uso de tierra y agua y el cambio climático se consideran importantes retos e incertidumbres. Al final, la conservación de la trucha del Pacífico depende de qué tan bien se comprendan y abordan estos temas, y de las soluciones que les permitan a estas especies coexistir con una gama creciente de influencias humanas. Conservation de la diversité de la truite du Pacifique indigène dans l'ouest de l'Amérique du NordLes truites du Pacifique ou Oncorhynchus spp. dans l'ouest...

Changes in the coastal landscape of Southern Sinaloa (Mexico), between 2000 and 2010, were analyzed to relate spatial variations in wetlands extent with the provision and economic value of the ecosystem services (ES). Remote sensing techniques applied to Landsat TM imagery were used to evaluate land use/land cover changes while the value transfer method was used to assess the value of ES by land cover category. Five wetland types and other four land covers were found as representative of the coastal landscape. Findings reveal a 14 % decrease in the saltmarsh/forested mangrove area and a 12 % increase in the area of shrimp pond aquaculture (artificial wetland) during the study period. ES valuation shows that the total value flow increased by 9 % from $215 to $233 million (2007 USD) during the 10-year period. This increase is explained as result of the high value worldwide assigned to saltmarsh. We recognize limitations in the transfer-based approach in quantifying and mapping ES values in the region, but this method provides with value estimates spatially defined, and also provides some guidance in the preliminary screening of policies and projected development in the context of data-scarce regions.

A preliminary assessment of growth performance and yield of subadult Pacific red snapper Lutjanus peru raised in floating sea cages was conducted by measuring fish length, weight, feed conversion, and survival rate during a 120‐d grow‐out trial at Punta el Caballo Beach, Nayarit State, Mexico. Nine floating cages (12.5‐m3 capacity) were used as experimental units. Fish were stocked in triplicate treatment cages at 30, 50, and 70 fish/m3 (1.9, 3.3, and 4.4 kg/m3, respectively) using more than 5,600 wild subadults (mean initial weight ±SD = 63.9 ± 1.4 g) as initial fish stock. Fish were fed twice per day with a sinking commercial pellet, and dissolved oxygen, temperature, pH, transparency, and ammonia nitrogen in each cage were recorded weekly. After 120 d, the mean individual weight at harvest was inversely related to stocking density. Mean final weight, weight gain, and specific growth rate differed among groups, with the highest values recorded for the 30‐fish/m3 density (233.4 ± 5.3 g [mean ± SD], 1.4 g/d, and 1.1% per day, respectively). Mean final body length, feed conversion, condition index, and survival did not differ among density treatments. Net yield (mean ± SD) ranged from 5.0 ± 0.2 kg/m3 (30‐fish/m3 treatment) to 7.9 ± 0.3 kg/m3 (70‐fish/m3 treatment) and differed among the treatments. Considering the initial biomass and density, the 70‐fish/m3 treatment produced a higher total biomass (mean ± SD = 152.9 ± 2.4 kg) but a lower average weight than the 50‐ and 30‐fish/m3 treatments. Our findings suggest that at all stocking densities tested, subadult Pacific red snapper will grow in floating sea cages without significant mortalities. A benefit–cost analysis must be achieved to define the best treatment in economic terms.

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