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Full-Text Articles in Environmental Sciences

Resurgence Of An Apex Marine Predator And The Decline In Prey Body Size, Jan Ohlberger, Daniel E. Schindler, Eric J. Ward, Timothy E. Walsworth, Timothy E. Essington Dec 2019

Resurgence Of An Apex Marine Predator And The Decline In Prey Body Size, Jan Ohlberger, Daniel E. Schindler, Eric J. Ward, Timothy E. Walsworth, Timothy E. Essington

Watershed Sciences Faculty Publications

In light of recent recoveries of marine mammal populations worldwide and heightened concern about their impacts on marine food webs and global fisheries, it has become increasingly important to understand the potential impacts of large marine mammal predators on prey populations and their life-history traits. In coastal waters of the northeast Pacific Ocean, marine mammals have increased in abundance over the past 40 to 50 y, including fish-eating killer whales that feed primarily on Chinook salmon. Chinook salmon, a species of high cultural and economic value, have exhibited marked declines in average size and age throughout most of their North …


Review Of The Negative Influences Of Non-Native Salmonids On Native Fish Species, Kelly C. Turek, Mark A. Pegg, Kevin L. Pope Apr 2013

Review Of The Negative Influences Of Non-Native Salmonids On Native Fish Species, Kelly C. Turek, Mark A. Pegg, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Non-native salmonids are often introduced into areas containing species of concern, yet a comprehensive overview of the short- and long-term consequences of these introductions is lacking in the Great Plains. Several authors have suggested that non-native salmonids negatively influence species of concern. The objective of this paper is to review known interactions between non-native salmonids and native fishes, with a focus on native species of concern. After an extensive search of the literature, it appears that in many cases non-native salmonids do negatively influence species of concern (e.g., reduce abundance and alter behavior) via different mechanisms (e.g., predation and competition). …


What Limits Tailed Frog Tadpole Density And Distribution In Western Montana Streams?, Megan Barker May 1996

What Limits Tailed Frog Tadpole Density And Distribution In Western Montana Streams?, Megan Barker

Undergraduate Honors Capstone Projects

We explored the possible limitation of temperature and other habitat features on tailed frog tadpole populations in northwestern Montana. We sampled densities and habitat features in two regions with different climatic regimes and in streams with and without tadpoles, expecting larger density and size in the warmer region. We also expected habitat conditons to be more optimal (higher gradient, swifter velocity, and less canopy cover) in streams with tadpoles. Temperature appeared to positively influence tadpole size, though both tadpole size and density were strongly correlated with other variables. Density was correlated with gradient, canopy, depth, and elevation, whereas length was …