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The article provides an overview of a study by P. S. Rand et al. that won the Robert L. Kendall Best Paper in the periodical "Transactions of the American Fisheries Society" in 2007. The researchers examined the potential effects of changing water discharges and warming water temperatures on adult sockeye salmon swimming upstream to spawn in the Fraser River, British Columbia. They have determined that declining river flows would offset the increased energy requirements of warmer water temperatures.

It is often recognized, but seldom addressed, that a quantitative assessment of the cumulative effects, both additive and non-additive, of multiple stressors on fish survival would provide a more realistic representation of the factors that influence fish migration. This review presents a compilation of analytical methods applied to a well-studied fish migration, a more general review of quantitative multivariable methods, and a synthesis on how to apply new analytical techniques in fish migration studies. A compilation of adult migration papers from Fraser River sockeye salmon Oncorhynchus nerka revealed a limited number of multivariable methods being applied and the sub-optimal reliance on univariable methods for multivariable problems. The literature review of fisheries science, general biology and medicine identified a large number of alternative methods for dealing with cumulative effects, with a limited number of techniques being used in fish migration studies. An evaluation of the different methods revealed that certain classes of multivariable analyses will probably prove useful in future assessments of cumulative effects on fish migration. This overview and evaluation of quantitative methods gathered from the disparate fields should serve as a primer for anyone seeking to quantify cumulative effects on fish migration survival. [ABSTRACT FROM AUTHOR]

Fraser River sockeye salmon have been the basis for a major commercial fishery shared by Canada and the United States, and an important cultural foundation for many aboriginal groups; they are also of huge ecological significance throughout the Fraser Basin. The potential for altered aquatic habitat and temperature regimes due to climate change is an important concern for Fraser River sockeye salmon. This paper characterizes the vulnerability of Fraser River sockeye salmon to future climate change using an approach that is novel on three counts. First, previous efforts to assess the vulnerability of salmon to climate change have largely focused on only part of the life cycle, whereas we consider climate vulnerability at all stages in the life cycle. Second, we use the available scientific literature to provide a basis for structuring and eliciting judgments from fisheries science and management experts who research and manage these systems. Third, we consider prospects for mitigating the effects of climate change on sockeye salmon. Tests showed that participants’ judgments differentiated in statistically significant ways among questions that varied in terms of life stages, spawning regions and climate scenarios. The consensus among participants was that Fraser River sockeye are most vulnerable to climate change during the egg and returning adult stages of the life cycle. A high temperature scenario was seen as imposing the greatest risk on sockeye stocks, particularly those that migrate to the upper reaches of the Fraser River system and spawn earlier in the summer. The inability to alter water temperature and the highly constrained nature of sockeye management, with competing gear types and sequential fisheries over a long distance, suggest the potential to mitigate adverse effects is limited. Fraser River sockeye already demonstrate a great deal of adaptive capacity in utilizing heterogeneous habitats in different river sub-basins. This adaptability points to the potential value of policies to make stocks more resilient to uncertain futures. [Copyright &y& Elsevier]

This paper extends a state–space Bayesian mark–recapture framework to multiple-recapture data to estimate fishery-specific capture and mortality rates and seasonal movement rates for fish in different length classes. The methodology is applied to tag recapture data for white sturgeon (Acipenser transmontanus) collected in the recreational fishery and the Canadian Department of Fisheries and Ocean’s test fishery at Albion in the lower Fraser River. Significant differences were found between some estimated movement rates by season and length class, supporting the notion of there being marked differences in seasonal movement patterns between different life history stages of A. transmontanus in the lower Fraser River. Uncertainty in the tag reporting rate parameter, quantified using a recreational creel sampling program, is summarized by a prior distribution. The utility of recreational fishing effort as a model covariate in accounting for seasonal and spatial variation in recapture rates is addressed using Bayesian model evaluation criteria. The data provide strong support in favour of models that include fishing effort as a covariate. The appropriate level of stratification for the recreational catchability parameter q is assessed using Bayesian model evaluation criteria; models in which q is estimated by season and length class have the highest posterior probabilities. [ABSTRACT FROM AUTHOR]

This paper summarizes the results of six seasons of archaeological fieldwork conducted at the Scowlitz site located at the confluence of the Harrison and Fraser Rivers in SW British Columbia, Canada. Research beginning in 1992 has revealed a complex sequence of site use beginning with a residential occupation about 3000 years ago. After some 1500 years the site became a cemetery, featuring some of the best preserved examples of the burial mound and cairn complex remaining on the Northwest Coast. Then, 1000 years ago, the site added seasonal use for resource processing while continuing as a cemetery. In the protohistoric and historical periods the site was used as a fishing camp and, still, as a cemetery. We discuss the implications of the Scowlitz site for understanding the development of complex hunting-fishing-gathering societies on the Northwest Coast. [ABSTRACT FROM AUTHOR]

Instability in homogeneous and density stratified shear flows may be interpreted in terms of the interaction of two (or more) otherwise free waves in the velocity and density profiles. These waves exist on gradients of vorticity and density, and instability results when two fundamental conditions are satisfied: (I) the phase speeds of the waves are stationary with respect to each other (“phase-locking“), and (II) the relative phase of the waves is such that a mutual growth occurs. The advantage of the wave interaction approach is that it provides a physical interpretation to shear flow instability. This paper is largely intended to purvey the basics of this physical interpretation to the reader, while both reviewing and consolidating previous work on the topic. The interpretation is shown to provide a framework for understanding many classical and nonintuitive results from the stability of stratified shear flows, such as the Rayleigh and Fjørtoft theorems, and the destabilizing effect of an otherwise stable density stratification. Finally, we describe an application of the theory to a geophysical-scale flow in the Fraser River estuary. [ABSTRACT FROM AUTHOR]