Trends in Characteristics of Yellowstone Lake Cutthroat Trout, Associated Factors, and Evidence of a Population Shift

Comprehensive time-series data for Yellowstone cutthroat trout (Oncorhynchus clarkia bouvieri; YCT) based on samples taken between 1977 and 2007 from the spawning run (spring; n = 29 yrs) of a tributary (Clear Creek) of Yellowstone Lake or caught in gill nets set (fall; n = 30 years) at established locations in the lake were examined to identify (1) associations between population characteristics within and between capture methods, as well as temporal trends in those characteristics, (2) evidence of informative shifts in population characteristics, and (3) factors that may have importantly affected the dynamics of the lacustrine-adfluvial YCT population of the tributary. Temporal increases in mean TL of YCT in the spawning run and of prespawners, i.e., YCT whose gonads indicated the fish would have spawned the next year, in the gillnet catch and concurrent declines in run size and prespawner catch were suggestive of an effect of YCT population density on the somatic growth of the fish. Similarly, a concurrent increase in mean TL of gillnetted YCT 100-199 mm long was indicated by the polynomial regression results, which also suggested statistical change points in the temporal trends for each of those variables. Contrasting those trends was that for mean TL of gillnetted YCT 200-299 mm long, whose general decline during the past two decades was attributed to predation by nonnative lake trout (Salvelinus namaycush). Collectively, these trends provided evidence of a YCT population shift. Correlation results indicated YCT in the spawning run could not be unequivocally assigned to any particular lake region. Multiple regression analyses showed that Clear Creek run size was strongly affected by parental run size 5 yrs earlier and a measure of climate 5 yrs earlier

The structural properties of sexual fantasies for sexual offenders : a preliminary model

While the phenomenon of sexual fantasy has been researched extensively, little contemporary inquiry has investigated the structural properties of sexual fantasy within the context of sexual offending. In this study, a qualitative analysis was used to develop a descriptive model of the phenomena of sexual fantasy during the offence process. Twenty-four adult males convicted of sexual offences provided detailed retrospective descriptions of their thoughts, emotions and behaviours—before, during and after their offences. A data-driven approach to model development, known as Grounded Theory, was undertaken to analyse the interview transcripts. A model was developed to elucidate the structural properties of sexual fantasy in the process of sexual offending, as well as the physiological and psychological variables associated with it. The Sexual Fantasy Structural Properties Model (SFSPM) comprises eight categories that describe various properties of sexual fantasy across the offence process. These categories are: origin, context, trigger, perceptual modality, clarity, motion, intensity and emotion. The strengths of the SFSPM are discussed and its clinical implications are reviewed. Finally, the limitations of the study are presented and future research directions discussed

Why Should We Preserve Fishless High Mountain Lakes?

High mountain lakes are originally fishless, although many have had introductions of non-native fish species, predominantly trout, and recently also minnows introduced by fishermen that use them as live bait. The extent of these introductions is general and substantial often involving many lakes over mountain ranges. Predation on native fauna by introduced fish involves profound ecological changes since fish occupy a higher trophic level that was previously inexistent. Fish predation produces a drastic reduction or elimination of autochthonous animal groups, such as amphibians and large macroinvertebrates in the littoral, and crustaceans in the plankton. These strong effects raise concerns for the conservation of high mountain lakes. In terms of individual species, those adapted to live in larger lakes have suffered a higher decrease in the size of their metapopulation. This ecological problem is discussed from a European perspective providing examples from two study areas: the Pyrenees and the Western Italian Alps. Species-specific studies are urgently needed to evaluate the conservation status of the more impacted species, together with conservation measures at continental and regional scales, through regulation, and at local scale, through restoration actions, aimed to stop further invasive species expansions and to restore the present situation. At different high mountain areas of the world, there have been restoration projects aiming to return lakes to their native fish-free status. In these areas autochthonous species that disappeared with the introduction of fish are progressively recovering their initial distribution when nearby fish-free lakes and ponds are available

Climate Change, Forests, Fire, Water, and Fish: Building resilient landscapes, streams, and managers

Fire will play an important role in shaping forest and stream ecosystems as the climate changes. Historic observations show increased dryness accompanying more widespread fire and forest die-off. These events punctuate gradual changes to ecosystems and sometimes generate stepwise changes in ecosystems. Climate vulnerability assessments need to account for fire in their calculus. The biophysical template of forest and stream ecosystems determines much of their response to fire. This report describes the framework of how fire and climate change work together to affect forest and fish communities. Learning how to adapt will come from testing, probing, and pushing that framework and then proposing new ideas. The western U.S. defies generalizations, and much learning must necessarily be local in implication. This report serves as a scaffold for that learning. It comprises three primary chapters on physical processes, biological interactions, and management decisions, accompanied by a special section with separately authored papers addressing interactions of fish populations with wildfire. Any one of these documents could stand on its own. Taken together, they serve as a useful reference with varying levels of detail for land managers and resource specialists. Readers looking for an executive summary are directed to the sections titled “Introduction” and “Next Steps.

Influence of barriers to movement on within-watershed genetic variation of coastal cutthroat trout

Because human land use activities often result in increased fragmentation of aquatic and terrestrial habitats, a better understanding of the effects of fragmentation on the genetic heterogeneity of animal populations may be useful for effective management. We used eight microsatellites to examine the genetic structure of coastal cutthroat trout (Oncorhynchus clarki clarki) in Camp Creek, an isolated headwater stream in western Oregon. Our objectives were to determine if coastal cutthroat trout were genetically structured within streams and to assess the effects of natural and anthropogenic barriers on coastal cutthroat trout genetic variation. Fish sampling occurred at 10 locations, and allele frequencies differed significantly among all sampling sections. Dispersal barriers strongly influenced coastal cutthroat trout genetic structure and were associated with reduced genetic diversity and increased genetic differentiation. Results indicate that Camp Creek coastal cutthroat trout exist as many small, partially independent populations that are strongly affected by genetic drift. In headwater streams, barriers to movement can result in genetic and demographic isolation leading to reduced coastal cutthroat trout genetic diversity, and potentially compromising long-term population persistence. When habitat fragmentation eliminates gene flow among small populations, similar results may occur in other species. http://www.dx.doi.org/10.1890/04-009

Concurrent Sessions C: Ecological Consequences of Partial Passage - Headwater Cutthroat Trout Movement Behaviors and Timing

Coastal cutthroat trout Oncorhynchus clarkii clarkii are the most widely distributed native salmonid in the forested watersheds of western Oregon. Populations in headwater streams have evolved on concordance with the physicochemical template that defines these complex aquatic networks. For example, behavioral patterns vary from small tributaries where local movements, within and among stream segments are common, to larger mainstem systems where migratory individuals are the dominant form. Because factors that may influence the relative abundance of these life-history types are poorly understood, we have been studying coastal cutthroat trout in watersheds ranging from 70 to 2,200 ha. Movement and distribution are assessed using continuous electrofishing surveys, passive integrated transponders (PIT tags) with arrays of swim-through antennas, and seasonal mobile antenna surveys. We are evaluating the resulting life-history patterns in relation to physical habitat, fish density, hydrology, connectivity, watershed size, and disturbance at a variety of spatial scales. Because these data span a 10-year period, we have been able to explore the influence of inter-annual variation in the amount, and temporal distribution of water on these critical patterns that are so closely linked to individual fitness and population persistence. The following results are preliminary. Results suggest that a greater proportion of fish exhibit migratory behavior as watershed size or connectivity increases. Depending on channel size, movement was restricted during low-flow periods. The mobile fraction of adult age 1+ cutthroat varied among tributaries within and among watersheds and individuals moving from tributaries to mainstem habitats on average experienced increased growth rates while individuals moving from mainstem to tributary habitats did not