Feeding rate of young-of-the-year ruffe on eggs of lake whitefish

Timothy J. Desorcie; Thomas A. Edsall

doi:10.1080/02705060.1995.9663442

Home/Archive/USGS

USGS · 1000824

Feeding rate of young-of-the-year ruffe on eggs of lake whitefish

Timothy J. Desorcie·Thomas A. Edsall

View original source ↗Export metadata ↓

Abstract

We measured the feeding rate of individual (0.6-12.2 g) young-of-the-year ruffe (Gymnocephalus cernuus) on the live eggs of lake whitefish (Coregonus clupeaformis) at 3, 5, and 9 degrees C in the laboratory. These temperatures were selected because they covered the range of lake temperatures over which eggs of most Great Lakes coregonines would be most vulnerable to predation by ruffe. Ruffe readily consumed lake whitefish eggs, and regression analysis showed consumption increased with ruffe size and water temperature. Mean daily egg consumption as a percent of mean ruffe body weight was 0.25% at 3 degrees C, 0.59% at 5 degrees C, and 1.00% at 9 degrees C.

Explore related subjects

Journal of Freshwater Ecology Article

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Timothy J. Desorcie, Thomas A. Edsall. 2011-01-06. Feeding rate of young-of-the-year ruffe on eggs of lake whitefish. https://doi.org/10.1080/02705060.1995.9663442

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

Rain interacts with directional wind to cause nest failures within breeding colonies of Western and Clark's Grebes

Western Grebe ( Aechmophorus occidentalis ) and Clark's Grebe ( Aechmophorus clarkii ) populations have declined across their range, and they are species of high conservation concern. Cascade Reservoir in central Idaho supports one of the largest breeding colonies of Aechmophorus grebes in North America (and the largest in Idaho), but few offspring are produced from the colony in most years. Low fecundity and little natal recruitment may be the proximate cause of Aechmophorus grebe population declines, but the ultimate cause of low recruitment is not known. One hypothesis for the low fecundity at Cascade Reservoir (and at other grebe colonies in the region) is that waves on freshwater breeding lakes inundate nests and cause pairs to abandon their nests. We tested that hypothesis by examining whether nest survival was negatively associated with changes in daily water level, daily peak wind speed and daily peak wind direction (i.e. winds that push water into the breeding colony). We also included daily mean temperature and daily total precipitation to evaluate a more general hypothesis that weather events caused nest failures. We used aerial imagery obtained from repeated drone flights to create encounter histories for 3888 Aechmophorus grebe nests to then estimate daily nest survival and evaluate whether daily water level, daily peak wind speed and daily peak wind direction (as predicted by the wind-driven wave hypothesis) were important causes of nest failure relative to other factors that commonly affect daily nest survival in birds. Nesting success was alarmingly low and we found some support for the wave inundation hypothesis; the results suggest that nesting attempts are more likely to fail on days with precipitation combined with winds blowing into the colony. Our results are the first to show that wind and precipitation affect the nest fate of Aechmophorus grebes.

Idaho↗

USGS2026

Variation in diet and lipid content of age-0 sturgeon (Scaphirhynchus sp.) in the lower Missouri River basin

Shovelnose sturgeon ( Scaphirhynchus platorynchus ) and related endangered pallid sturgeon ( S. albus ) are species of interest in the highly modified Missouri River. Scaphirhynchus sturgeon require long distances of riverine habitat for the development of drifting free embryos along with suitable foraging habitat during the subsequent transition to exogenous feeding. Working with specimens collected by the US Army Corps of Engineers and Nebraska Game and Parks Commission, we examined diet composition of age-0 (<12 cm) sturgeon at four reaches in the lower Missouri River to examine the potential role of prey acquisition at this vulnerable life stage. In general, Ephemeroptera were more represented at reaches further upstream in the lower Missouri River, whereas Diptera larvae were the dominant prey item in reaches downstream. Body condition, as measured by total lipid content and length‒weight regressions, exhibited spatial differences in 2016 but not in 2017. Even with differences in prey frequencies and numbers consumed, percent consumption regardless of prey type remained consistent among reaches within years, but was overall higher in 2016 when river discharge was greater. Although temporal and spatial differences were observed in condition, comparisons using previous data from 2014 and 2015 suggest that these condition results were not driven by the longitudinal variability in prey composition as the reaches below Kansas city yielded relatively high and low lipid values despite the limited consumption of ephemeropteran prey relative to upstream reaches. Although it is unknown if any of the observed differences affected survival, our results, coupled with previous work, suggest that age-0 sturgeon can opportunistically forage in the lower Missouri River.

Missouri River↗

USGS2025

Relationships between larval fish drift, time of day and discharge in an Ozark stream

We examined the relationship between larval fish numbers and discharge during a high flow event in Bear Creek, Arkansas, a small Ozark stream. Additionally, we examined the relationship between fish numbers and time of day, and the spatial distribution of families and size classes. A total of 3,083 fish from five families were collected. Leuciscidae was the dominant family collected, followed by Percidae, and Catostomidae. Larval fish in Bear Creek were not susceptible to increased discharge from the flood event, as all three families exhibited strong significant negative relationships to discharge at night when discharge began to decline. Larval fish in Bear Creek drifted significantly more at night than during the day, with the exception of large percids, which exhibited no diel pattern. Leuciscidae and small Percidae showed a spatial pattern of distribution across the stream at night, with higher drift densities in near shore nets. The results from our study indicate that fish drift in Bear Creek was an active process, with most larval fish drifting in response to decreased light intensity. We suggest future studies consider the effects of flood intensity on larval fish drift relative to diel periodicity.

Arkansas↗