25 research outputs found
Recommended from our members
A comprehensive approach for habitat restoration in the Columbia Basin
The Columbia Basin once supported a diversity of native fishes and large runs of anadromous salmonids that sustained substantial fisheries and cultural values. Extensive land conversion, watershed disruptions, and subsequent fishery declines have led to one of the most ambitious restoration programs in the world. Progress has been made, but restoration is expensive (exceeding US $300 M/year), and it remains unclear whether habitat actions, in particular, can be successful. A comprehensive approach is needed to guide cost-effective habitat restoration. Four elements that must be addressed simultaneously are (1) a scientific foundation from landscape ecology and the concept of resilience, (2) broad public support, (3) governance for collaboration and integration, and (4) a capacity for learning and adaptation. Realizing these in the Columbia Basin will require actions to rebalance restoration goals to include diversity, strengthen linkages between science and management, increase public engagement, work across traditional ecological and social boundaries, and learn from experience.This is the publisher’s final pdf. The published article is copyrighted by Taylor & Francis and can be found at: http://www.tandfonline.com/loi/ufsh20#.VUEib2MywS
Rapid Natural Habitat Degradation and Consequences for Sockeye Salmon Production in the Chignik Lakes System, Alaska
NR
Chignik salmon studies: Consumption of sockeye salmon fry by juvenile coho salmon in the Chignik Lake, AK: Implications for salmon management
NMF
Data from: Size-selectivity of predation by brown bears depends on the density of their sockeye salmon prey
Can variation in prey density drive changes in the intensity or direction of selective predation in natural systems? Despite ample evidence of density-dependent selection, the influence of prey density on predatory selection patterns has seldom been investigated empirically. We used 20 years of field data on brown bears (Ursus arctos) foraging on sockeye salmon (Oncorhynchus nerka) in Alaska, to test the hypothesis that salmon density affects the strength of size-selective predation. Measurements from 41,240 individual salmon were used to calculate variance-standardized selection differentials describing the direction and magnitude of selection. Across the time series, the intensity of predatory selection was inversely correlated with salmon density; greater selection for smaller salmon occurred at low salmon densities as bears’ tendency to kill larger-than-average salmon was magnified. This novel connection between density dependence and selective predation runs contrary to some aspects of optimal foraging theory and differs from many observations of density-dependent selection because (1) the direction of selection remains constant while its magnitude changes as a function of density and (2) stronger selection is observed at low abundance. These findings indicate that sockeye salmon may be subject to fishery-induced size selection from both direct mechanisms and latent effects of altered predatory selection patterns on the spawning grounds, resulting from reduced salmon abundance
Chignik Salmon Studies: Investigations of Salmon Populations, Hydrology, and Limnology of the Chignik Lakes, Alaska, during 2003-2004
NMF
Chignik Lakes Research: Investigations of salmon populations, hydrology, and limnology of the Chignik Lakes, Alaska during 2000.
NMF
Chignik salmon studies: Investigations of salmon populations, hydrology, and limnology of the Chignik Lakes, Alaska
NMFS, CRA