Applying a gene-suite approach to examine the physiological status of wild-caught walleye (Sander vitreus)

Molecular techniques have been increasingly used in a conservation physiology framework to provide valuable information regarding the mechanisms underlying responses of wild organisms to environmental and anthropogenic stressors. In the present study, we developed a reference gill transcriptome for walleye (Sander vitreus) allowing us to pair a gene-suite approach with multivariate statistics to examine the physiological status of wild-caught walleye. For molecular analyses of wild fish, the gill is a useful target for conservation studies, not only because of its importance as an indicator of the physiological status of fish but also because it can be biopsied non-lethally. Walleye were non-lethally sampled following short- (∼1.5 month) and long-term (∼3.5 month) holding in the Delta Marsh, that is located south of Lake Manitoba in Manitoba, Canada. Large-bodied walleye are held in the Delta Marsh from late April to early August by exclusion screens used to protect the marsh from invasive common carp (Cyprinus carpio), exposing fish to potentially stressful water quality conditions. Principal components analysis (PCA) revealed patterns of transcript abundance consistent with exposure of fish to increasingly high temperature and low oxygen conditions with longer holding in the marsh. For example, longer-term holding in the marsh was associated with increases in the mRNA levels of heat shock proteins and a shift in the mRNA abundance of aerobic to anaerobic metabolic genes. Overall, the results of the present study suggest that walleye held in the Delta Marsh may be exhibiting sub-lethal responses to high temperature and low oxygen conditions and provides valuable information for managers invested in mediating these impacts to a local species of conservation concern. More broadly, we highlight the usefulness of pairing transcriptomic techniques with multivariate statistics to address potential confounding factors that can affect measured physiological responses of wild-caught fish.Lay summaryNon-lethal molecular techniques were used to assess the physiological status of wild-caught walleye confined in the Delta Marsh, Manitoba, Canada, because of common carp exclusion screens. Walleye sampled during the warmest months of the year exhibited responses to elevated temperature and low oxygen conditions, suggesting sub-lethal effects of local conditions.

Applying a gene-suite approach to examine the physiological status of wild-caught walleye (Sander vitreus)

Molecular techniques have been increasingly used in a conservation physiology framework to provide valuable information regarding the mechanisms underlying responses of wild organisms to environmental and anthropogenic stressors. In the present study, we developed a reference gill transcriptome for walleye (Sander vitreus), allowing us to pair a gene-suite approach (i.e. multiple genes across multiple cellular processes) with multivariate statistics to examine the physiological status of wild-caught walleye. For molecular analyses of wild fish, the gill is a useful target for conservation studies, not only because of its importance as an indicator of the physiological status of fish but also because it can be biopsied non-lethally. Walleye were non-lethally sampled following short- (~1.5 months) and long-term (~3.5 months) confinement in the Delta Marsh, which is located south of Lake Manitoba in Manitoba, Canada. Large-bodied walleye are confined in the Delta Marsh from late April to early August by exclusion screens used to protect the marsh from invasive common carp (Cyprinus carpio), exposing fish to potentially stressful water quality conditions. Principal components analysis revealed patterns of transcript abundance consistent with exposure of fish to increasingly high temperature and low oxygen conditions with longer holding in the marsh. For example, longer-term confinement in the marsh was associated with increases in the mRNA levels of heat shock proteins and a shift in the mRNA abundance of aerobic to anaerobic metabolic genes. Overall, the results of the present study suggest that walleye confined in the Delta Marsh may be exhibiting sub-lethal responses to high temperature and low oxygen conditions. These results provide valuable information for managers invested in mediating impacts to a local species of conservation concern. More broadly, we highlight the usefulness of pairing transcriptomic techniques with multivariate statistics to address potential confounding factors that can affect measured physiological responses of wild-caught fish.

Report on Birds Banded in the Dune-ridge Forest, Delta Marsh, Manitoba, 1973-1988

Report on Birds Banded in the Dune-ridge Forest, Delta Marsh, Manitoba, 1973-1988

Changes in Nesting Density of Baltimore Orioles (1976-1995) and Other Species in the Dune- Ridge Forest, Delta Marsh, MB: Response to an Outbreak of Forest Tent Caterpillar?

Changes in Nesting Density of Baltimore Orioles (1976-1995) and Other Species in the Dune- Ridge Forest, Delta Marsh, MB: Response to an Outbreak of Forest Tent Caterpillar?

Incursion of Post-Breeding Pine Siskins in the Dune- Ridge Forest, Delta Marsh, Manitoba, 1985

Incursion of Post-Breeding Pine Siskins in the Dune- Ridge Forest, Delta Marsh, Manitoba, 1985

Evening Grosbeaks Feeding on Pupae of the Forest Tent Caterpillar in the Dune- Ridge Forest, Delta Marsh, Manitoba, Spring 1976

Evening Grosbeaks Feeding on Pupae of the Forest Tent Caterpillar in the Dune- Ridge Forest, Delta Marsh, Manitoba, Spring 1976

Yellow Warblers (Setophaga petechia) rear second broods in some years at Delta Marsh, Manitoba

Twenty cases of double brooding by colour-marked Yellow Warblers (Setophaga petechia) were recorded in 5 of 11 years (1975–1986, no data collected in 1977) during studies of breeding ecology in the dune-ridge forest at Delta Marsh, Manitoba (1 pair in 1975, 3 pairs in 1976, 3 pairs in 1984, 9 pairs in 1985, and 4 pairs in 1986). At least one member of each of the 20 pairs was marked. Eleven pairs re-used their first nest for the second attempt, whereas 9 females built a new nest, in 5 cases because the original nests had disintegrated. Four of the second nests (3 in 1985 and 1 in 1986) were parasitized by Brown-headed Cowbirds (Molothrus ater). All 20 first nests produced at least one young, a condition for double brooding, and 13 second nests, including 3 that were parasitized, were successful. Failure of about 60% of annual nesting attempts at Delta Marsh may contribute to the low number of pairs with double broods recorded in some years and the absence of double brooding in years of comparable phenology. This is the first published evidence of double brooding in the Yellow Warbler.