Migratory and rearing pathways of juvenile spring Chinook salmon (Oncorhynchus tshawytscha) were documented in the Willamette River basin to identify life histories and estimate their contribution to smolt production and population stability. We identified six primary life histories that included two phenotypes for early migratory tactics: fry that migrated up to 140–200 km shortly after emergence (movers) and fish that reared for 8–16 months in natal areas (stayers). Peak emigration of juvenile salmon from the Willamette River was in June–July (subyearling smolts), March–May (yearling smolts), and November–December (considered as “autumn smolts”). Alternative migratory behaviors of juvenile salmon were associated with extensive use of diverse habitats that eventually encompassed up to 400 rkm of the basin, including tributaries in natal areas and large rivers. Juvenile salmon that reared in natal reaches and migrated as yearlings were the most prevalent life history and had the lowest temporal variability. However, the total productivity of the basin was increased by the contribution of fish with dispersive life histories, which represented over 50% of the total smolt production. Life-history diversity reduced the variability in the total smolt population by 35% over the weighted mean of individual life histories, providing evidence of a considerable portfolio effect through the asynchronous contributions of life histories. Protecting and restoring a diverse suite of connected habitats in the Willamette River basin will promote the development and expression of juvenile life histories, thereby providing stability and resilience to native salmon populations.

We estimated the hooking mortality of spring Chinook salmon Oncorhynchus tshawytscha that were caught and released to determine whether selective fishing on hatchery Chinook salmon would reduce harvest mortality of wild fish in a sport fishery in the lower Willamette River, Oregon. Hooking mortality in the fishery was estimated from hooking mortality rates for each of five anatomical locations (jaw, 2.3%; tongue, 17.8%; eye, 0.0%; gills, 81.6%; and esophagus–stomach, 67.3%) and from the frequency of these anatomical locations in the sport fishery (jaw, 81.5%; tongue, 5.1%; eye, 0.4%; gills, 5.1%; and esophagus–stomach, 7.8%). Mortality rates by anatomical location were estimated from recaptures of 869 tagged fish that were experimentally angled and of 825 tagged controls that were trapped in a nearby fishway. Anatomical hook locations in the lower Willamette River sport fishery were determined with creel surveys. We estimated hooking mortality rates of 12.2% for wild Chinook salmon caught and released in the sport fishery and 3.2% for the entire run of wild Chinook salmon based on a mean encounter rate of 26%. Hook location was the primary factor affecting recapture of hooked fish, but fish length, gear type, bleeding, and the elapsed time to unhook fish were also significant factors. A selective sport fishery in the lower Willamette River can be used to reduce harvest mortality on runs of wild Chinook salmon while maintaining fishing opportunity on hatchery Chinook salmon. The effect of selective fisheries for Chinook salmon in other rivers would depend on the frequency distribution of anatomical hook locations and on river‐specific encounter rates.

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Although the participation of the macromedusae has been relatively low, in areas of elevated concentration, the relative importance was high, making its participation almost exclusive among other zoological groups. Those registers of abundance and the respective areas of high concentration of macromedusae, which were associated to high primary production sites, may serve as a theoretical reference of the abundance of these organisms for future studies that aim to evaluate possible changes in jellyfish populations. Keywords: macromedusae, Rhacostoma atlanticum, Olindias sambaquiensis, bycatch, southern and southeastern Brazil.Evaluación preliminar de la captura incidental de medusas capturadas frente al sur y sureste de Brasil RESUMEN. El registro de formas macromedusoides de las clases Hydrozoa, Scyphozoa y Cubozoa en su hábitat en el sur y sureste de Brasil se efectuó mediante observadores científicos. Después de cada salida de pesca, se cuantificó la composición de la captura y se registró la localización de cada uno de los lances efectuados entre los años 2008 y 2011. El registro de las macromedusas se sistematizó para analizar su distribución espacio-temporal, áreas de concentración y su relación con los demás componentes del descarte de la pesca. El análisis de la captura analizada en 986 lances de pesca mostró que el porcentaje de organismos varió entre 6 y 16%. Las hidromedusas Rhacostoma atlanticum y Olindias sambaquiensis fueron las especies más abundantes y más ampliamente distribuidas. R. atlanticum fue registrada entre 20 y 140 m de profundidad y O. sambaquiensis en aguas más costeras, entre 10 y 70 m. Ninguna otra especie fue registrada en profundidades superiores a 60 m. Las áreas de mayor concentración fueron el litoral centro-norte de Santa Catarina y el litoral de Paraná, sector norte de São Paulo y sector centro-norte de Rio Grande do Sul. A pesar que el porcentaje de estos organismos fue relativamente bajo, en áreas de elevada concentración, la importancia relativa fue alta, y su presencia fue casi exclusivo entre los demás grupos zoológicos. Estos registros de abundancia y las respectivas áreas de alta concentración de macromedusae, asociadas a los áreas de alta producción primaria, pueden servir como referencia teórica de la abundancia de estos organismos para futuros estudios cuyo objetivo sea evaluar los posibles cambios en las poblaciones de medusas. Palabras clave: macromedusas, Rhacostoma atlanticum, Olindias sambaquiensis, pesca incidental, sur y sureste de Brasil.