Two replications of a half dial lei cross experiment were performed among four inbred lines of mosquitofish, Gambusia affinis.
These inbred lines originated from three random-bred stocks: OR,
TX and CD. The experiment was conducted as a completely randomized
design. Experimental material consisted of parental lines and F₁ populations maintained...
Florida is a hotspot for nonindigenous fishes with over 30 species established, although few of these are small-bodied species. One hypothesis for this pattern is that biotic resistance of native species is reducing the success of small-bodied, introduced fishes. The eastern mosquitofish Gambusia holbrooki is common in many freshwater habitats...
With many ecosystems now supporting multiple nonnative species from different trophic levels, it can be challenging to disentangle the net effects of invaders within a community context. Here, we combined wetland surveys with a mesocosm experiment to examine the individual and combined effects of nonnative fish predators and nonnative bullfrogs...
Predator-prey interactions, as measured by the consumption
and growth rates of a predator (Micropterus salmoides) and by the
observed activities of both predator and prey (Gambusia affinis),
were found to be sensitive to sublethal levels of ammonium chloride
(reported as unionized ammonia NH₃).
One bass and 15, 30, 60 or...
We examined the multivariate life-history trajectories of age 0 and age 1 female Gambusia affinis to determine relative effects of age-based and environment-based cues on reproductive investment. Age 0 females decreased reproductive investment prior to the onset of fall and winter months, while age 1 females increased reproductive investment as...
The Willamette River flows north between the Cascade Mountains and Coast Range of western Oregon within a 29,728-km² basin. The fish community in the geologically young basin consists of 36 native species, but introductions of non-native fishes have added 33 additional species for a total of 69 fish species. During...
This book contains descriptions of 15 native and 16 nonnative fish (including origin, distribution, key characteristics, size, distinguishing features, color, diet, and other remarks) found in the Willamette River Basin's seasonal watercourses, with over a hundred photos to aid in identification. It also offers a succinct explanation of the Willamette...
To begin to understand freshwater seasonal floodplain fish communities in the context of human alteration of the physical system, species introductions and wetland restoration efforts, I studied fish assemblages in fifteen seasonal floodplain wetlands within four geographic regions (coastal, upper Columbia River estuary, Puget Sound and eastern Oregon/Washington) in the...
In coastal South Carolina, most impounded marshes are managed for waterfowl; fewer are managed for fishes. Tidal control is central to each strategy but raises concerns that nursery function could be impaired. This research examined the assemblage composition of fishes during early-life stages. We sampled two impoundments of each management...
The Upper Klamath Basin is an ecologically significant watershed that supports millions of migratory waterbirds along the Pacific Flyway in addition to an agricultural economy and a tribal fishery. This literature review and annotated bibliography is the basis for a capstone project to address the history, evolution, impacts, and responses...
Understanding the drivers of species occurrence is a fundamental goal in basic and applied ecology. Occupancy models have emerged as a popular approach for inferring species occurrence because they account for problems associated with imperfect detection in field surveys. Current models, however, are limited because they assume covariates are independent...
Full Text:
, including
mosquitofish (Gambusia affinis), largemouth bass
(Micropterus salmoides), and bluegill sunfish
This study¹ was undertaken: (1) to obtain information on the distribution of the snail, Oxytrema silicula, in three coastal rivers in Oregon, and the seasonal incidence of infection in these snails and in snails from an inland stream, with the cercariae of the trematode, Nanophyetus salinincola; (2) to follow cercarial...
The conservation of declining desert fish species requires the identification of relations between fish population dynamics and their environments. Dynamic occupancy modeling, an approach that requires less information than traditional mark-recapture studies, may help identify important factors affecting population processes and aid desert fish conservation and restoration efforts. I used...
Students sharpen analytical, logic, and problem solving tools by thinking critically about how human activities spread invasive species and how to control them.
Determining the mechanisms responsible for the success of invasive species is critical for
developing effective management strategies. Artificially draining managed wetlands to maintain natural
ephemeral conditions is a common practice in the Pacific Northwest and is assumed to kill invasive American
bullfrog (Lithobates catesbeianus) larvae, which typically overwinter in permanent...
In many animal species, males direct more intense courtship towards females they have not previously encountered,
than towards females with which they have previously mated. To test the factors responsible for this "Coolidge Effect", we need
studies on a wide range of taxa – including those with mating systems in...
OBJECTIVE. Hospital readmissions are a current target of initiatives to reduce healthcare costs. This study quantified the association between having a clinical culture positive for 1 of 3 prevalent hospital-associated organisms and time to hospital readmission.
DESIGN. Retrospective cohort study.
PATIENTS AND SETTING. Adults admitted to an academic, tertiary care...
