Stable oxygen and carbon isotope δ[superscript 18]O and δ[superscript 13]C analyses of otoliths are becoming increasingly common in fisheries science and management. However, little is known about the statistical properties of isotopic data and few attempts have been made to explore appropriate statistical methods that could be used for otolith...
We used simulated magnetic displacements to test orientation preferences of
juvenile steelhead trout (Oncorhynchus mykiss) exposed to magnetic fields
existing at the northernmost and southernmost boundaries of their oceanic
range. Fish reared in natural magnetic conditions distinguished between
these two fields by orienting in opposite directions, with headings that
would...
Full Text:
Sheet1
Nathan F. Putman, Amanda M. Meinke, and David L. G. Noakes
Rearing
We used simulated magnetic displacements to test orientation preferences of
juvenile steelhead trout (Oncorhynchus mykiss) exposed to magnetic fields
existing at the northernmost and southernmost boundaries of their oceanic
range. Fish reared in natural magnetic conditions distinguished between
these two fields by orienting in opposite directions, with headings that
would...
Full Text:
. Meinke3 and David L. G. Noakes1,3
1Department of Fisheries and Wildlife, Oregon State University
Piscivory by birds can be significant, particularly on fish in small streams and during seasonal low flow when available cover from predators can be limited. Yet, how varying amounts of cover may change the extent of predation mortality from avian predators on fish is not clear. We evaluated size-selective survival...
We used simulated magnetic displacements to test orientation preferences of juvenile steelhead trout (Oncorhynchus mykiss) exposed to magnetic fields existing at the northernmost and southernmost boundaries of their oceanic range. Fish reared in natural magnetic conditions distinguished between these two fields by orienting in opposite directions, with headings that would...
Morphologically divergent ecotypes arise in fish populations on postglacial time scales, and resource polymorphisms
are often invoked to explain their origin. However, genetic recombination can constrain the ability of divergent selection to produce
reproductive isolation in sympatry. Recombination breaks up favorable combinations of traits (”adaptive suites”) if individual
traits are...
Long-distance migrants, including Pacific salmon (Oncorhynchus
spp), can use geomagnetic information to navigate. We tested
the hypothesis that a “magnetic map” (i.e., an ability to extract
positional information from Earth’s magnetic field) also exists in a
population of salmon that do not undertake oceanic migrations.
This study examined juvenile Atlantic...
Straying by hatchery-reared salmon is a major concern for conservation and recovery of many salmon populations. Fisheries managers have attempted to minimize negative ecological and genetic interactions between hatchery and wild fish by using parr-smolt acclimation facilities to ensure successful olfactory imprinting and homing fidelity. However, the effectiveness of offsite...
The Pacific salmonid species Oncorhynchus mykiss is separated into a migratory form (steelhead trout) and a
non-migratory form (rainbow trout). A decrease in water temperature is likely a cue triggering downstream
behavior in the migratory form, and testosterone inhibits onset of this behavior. To elucidate differences in
sensitivity to water...
It is critical to study factors that are important for origin and maintenance of biological
diversity. A comparative approach involving a large number of populations is
particularly useful.We use this approach to study the relationship between ecological
factors and phenotypic diversity in Icelandic Arctic charr (Salvelinus alpinus).
Numerous populations of...