Temporal and spatial variation in the energy intake of a brook trout (Salvelinus fontinalis) population in an Appalachian watershed

2006 ◽  
Vol 63 (12) ◽  
pp. 2675-2686 ◽  
Author(s):  
Ryan M Utz ◽  
Kyle J Hartman
Keyword(s):  
Energy Intake ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Stomach Contents ◽  
Spatial And Temporal Variation ◽  
Feeding Rates ◽  
Temporal And Spatial Variation ◽  
The Mean ◽  
Temporal And Spatial ◽  
Very High

Stream-dwelling salmonids in eastern North America are often restricted to headwater watersheds, where productivity is low and thus feeding conditions are poor. We sought to quantify how energy intake varies with spatial and temporal variation by monitoring feeding rates in multiple sites over the course of two years. Daily rations were calculated for 939 fish by examining stomach contents. Maintenance rations were compared with daily rations using a bioenergetics model. Consumption peaked in spring, dropped substantially in summer, and remained low until the following spring. A minority of fish fed at very high levels during all seasons, elevating the mean consumption of the population. Fish occupying large sites with low trout densities consistently consumed more energy than fish in smaller streams with high trout densities. A direct relationship between trout density and mean consumption was observed during summer, when feeding conditions were poorest. Our findings suggest that within a headwater watershed, larger reaches of streams where fewer trout are found act as important feeding areas and thus may be important habitat for brook trout (Salvelinus fontinalis).

Food Specialization By Individual Trout

1972 ◽  
Vol 29 (11) ◽  
pp. 1615-1624 ◽  
Author(s):  
James E. Bryan ◽  
P. A. Larkin
Keyword(s):  
Rainbow Trout ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Stomach Contents ◽  
Cutthroat Trout ◽  
Salmo Gairdneri ◽  
Potential Prey ◽  
Repeated Observation ◽  
Size Growth ◽  
Salmo Clarki

Analyses of stomach contents showed that the kinds of prey eaten by brook trout (Salvelinus fontinalis), cutthroat trout (Salmo clarki), and rainbow trout (Salmo gairdneri) were seldom distributed at random among the individuals. Repeated observation of food eaten by individuals in a stream and ponds showed that prey types were eaten in proportions which were characteristic for an individual.Specialization occurred on several different kinds of prey. Although the degree of specialization was higher during shorter intervals, the data suggested that some specialization persisted for half a year. There were no striking correlations between degree of specialization and other individual properties such as size, growth rate, weight of food, number of food items, previous specialization, or area of recapture.In addition to the observations on trout in relatively undisturbed habitats, a field experiment was conducted using laboratory-reared rainbow trout held in small ponds. The food of each trout in the experiment was sampled repeatedly. In analysis of variance, interaction among the individuals and kinds of prey eaten showed that food specialization occurred. Both the absolute and relative abundance of potential prey were constant during the experiment.

Models of Ammonia Excretion for Brook Trout (Salvelinus fontinalis) and Rainbow Trout (Salmo gairdneri)

1980 ◽  
Vol 37 (9) ◽  
pp. 1421-1425 ◽  
Author(s):  
Larry J. Paulson
Keyword(s):  
Body Weight ◽  
Rainbow Trout ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Ammonia Excretion ◽  
Salmo Gairdneri ◽  
Feeding Rates ◽  
Data Set ◽  
Nitrogen Consumption ◽  
Good Agreement

Ammonia excretion by brook trout (Salvelinus fontinalis) and rainbow trout (Salmo gairdneri) was measured in relation to nitrogen consumption, body weight (15–154 g for rainbow trout and 50–360 g for brook trout), and temperature (11.2–21.0 °C) under laboratory conditions. Four natural diets, collected from Castle Lake, California, and a commercial pellet diet were fed to the trout in gelatin capsules at feeding rates from 2.5 to 5% body weight∙d−1. Nitrogen consumption was the most important factor influencing ammonia excretion, followed by body weight and temperature. Testing the models with an independent data set revealed good agreement between measured and predicted rates of excretion. The models seem to estimate adequately ammonia excretion by trout in both natural and artificial aquatic systems.Key words: models, ammonia excretion, nitrogen consumption, body weight, temperature, multiple regression, rainbow trout, brook trout

scholarly journals Variation in energy intake of female chimpanzees: comparing estimates based on feeding time versus energy ingestion rates

2016 ◽  
Author(s):  
Moreen Uwimbabazi ◽  
Richard W Wrangham ◽  
Zarin P Machanda ◽  
Nancy L Conklin-Brittain ◽  
Jessica M Rothman ◽  
...  
Keyword(s):  
Energy Intake ◽  
Ingestion Rate ◽  
Average Energy ◽  
Seasonal Fluctuation ◽  
Feeding Time ◽  
Feeding Rates ◽  
Ingestion Rates ◽  
Young Leaves ◽  
The Mean ◽  
Nutritional Studies

Different food items can provide calories at different rates, yet nutritional studies of primates are generally based on the proportion of time spent eating different foods. Accordingly, estimates of energy intake are potentially wrong. To assess the importance of this problem we observed 15 female chimpanzees from the Kanyawara chimpanzee community in Kibale National Park, Uganda for 15 months. Feeding rates were recorded and nutritional analyses assembled for 90 food types. Across all foods the mean estimated rate of energy ingestion was 8.8±7.6 Kcals/min. Energy ingestion rates varied among food types (F8,82,=2.24, p<0.05), being higher for ripe fruits (12.2±8.7Kcals/min) than for young leaves (7.8±7.9Kcals/min), piths (6.0±5.2Kcals/min) or seeds (2.8±1.9Kcals/min). Energy ingestion rates estimated assuming high %NDF fermentation (54.3%) were significantly higher than the rates at zero (0%) fermentation (t=6.14, p<0.01). At 54.3% NDF fermentation, estimated energy ingestion rate rose by 20.5% for ripe fruits (9.7 to 12.2 Kcals/min), and by 39.7% for young leaves (4.7 to 7.8Kcals/min). Chimpanzees spent a mean of 304±80 minutes feeding daily, indicating that daily energy intake averaged to 3029 ±1198Kcal. When chimpanzees spent >60% of feeding time on ripe fruits (N=79 days), the average energy intake (3367Kcal) was significantly higher than when they spent >60% of feeding time on herbaceous vegetation (2409Kcal, N=37 days) (F1,114=12.68, p<0.01). Our results highlight the value of using feeding rates to understand chimpanzee nutrition, and suggest that seasonal fluctuation in nutrient intake is more pronounced than indicated by variation in feeding time.

scholarly journals Effects of meal and body sizes on gastric evacuation rate in brooktrout Salvelinus fontinalis (Mitchill, 1814) fed commercial pellets in group feeding

2017 ◽  
Vol 64 (3) ◽  
Author(s):  
N. S. Bascinar ◽  
N. Bascinar ◽  
U. Khan ◽  
K. Seyhan
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Stomach Contents ◽  
Gastric Evacuation ◽  
Root Model ◽  
Feeding Regimes ◽  
Body Sizes ◽  
Group Feeding ◽  
Gastric Evacuation Rate ◽  
Square Root Model

The effects of meal and body sizes on gastric evacuation (GE) of brook trout Salvelinus fontinalis (Mitchill, 1814) were determined following group feeding instead of feeding individually maintained fish. The GE experiments included small (ranging from 64.75 to 69.72 g) and large fish (ranging from 161.59 to 170.95 g). Fish in each size group was fed with three different meal sizes under similar conditions. The stomach contents were then recovered at predetermined postprandial times by serial slaughtering. The square root model adequately described the course of GE in S. fontinalis independent of meal size. The estimates of mass and length exponent obtained from S. fontinalis fed individually are in line with the present estimates. The result of this study would facilitate the planning and management of feeding regimes for S. fontinalis to minimise food waste and optimise growth.

Spatial and temporal variation in the diet of double-crested cormorants (Phalacrocorax auritus) breeding on the lower Great Lakes in the early 1990s

1997 ◽  
Vol 54 (7) ◽  
pp. 1569-1584 ◽  
Author(s):  
J Neuman ◽  
D L Pearl ◽  
P J Ewins ◽  
R Black ◽  
D V Weseloh ◽  
...  
Keyword(s):  
Great Lakes ◽  
Breeding Season ◽  
Prey Species ◽  
Extensive Study ◽  
Spatial And Temporal Variation ◽  
Phalacrocorax Auritus ◽  
Temporal And Spatial Variation ◽  
Preferred Habitat ◽  
Spatial And Temporal Heterogeneity ◽  
Temporal And Spatial

We sampled 1573 pellets and 560 boli regurgitated at double-crested cormorant (Phalacrocorax auritus) colonies on the three lower Laurentian Great Lakes (Lake Ontario, Lake Huron, and Lake Erie) during the breeding season in 1992 and 1994. This constitutes the first extensive study of cormorant diet in this region. We found significant spatial and temporal heterogeneity in diet among colonies within a lake. Differences in diet among colonies were usually consistent with knowledge of changes in fish behaviour during the cormorant breeding season, differences in the surrounding bathymetry among breeding colonies, and the proximity of colonies to the preferred habitat of prey species. Our results indicate that temporal and spatial variation, as well as the technique for diet determination, are very important factors that must be considered when assessing the effects of double-crested cormorant predation on fisheries.

Relationship between Feeding and Activity Rates for Actively Foraging Juvenile Brook Trout (Salvelinus fontinalis)

1992 ◽  
Vol 49 (12) ◽  
pp. 2566-2573 ◽  
Author(s):  
Daniel Boisclair
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Total Activity ◽  
Energy Allocation ◽  
Energy Losses ◽  
Feeding Rates ◽  
Experimental Protocol ◽  
Total Consumption ◽  
Consumption Rates ◽  
Allocation Patterns

I tested the hypothesis of the existence of a significant positive linear relationship between activity and consumption rates for an actively foraging fish. Within-day variations in activity rates of 0 + brook trout (Salvelinus fontinalis) kept in enclosures were estimated using an underwater videocamera system. Consumption rates at different periods of that day were estimated using the variations of the digestive tract contents. Total consumption rates (i.e. sum of food ingested by all fish) ranged from values close to zero (−1.4 to 0.9; 12:30–24:00) to 12.7 cal/30 min (08:30–09:00). Total activity rates ranged from 0.06 (14:00–14:30) to 2.94 cal/30 min (08:30–09:00). My results indicate that, under specific environmental conditions, activity rates of brook trout are positively related to their feeding rates and, consequently, that the behavior of this actively foraging fish can result in the reduction of the energy losses associated with swimming during nonfeeding periods. My work also permits the development of an experimental protocol to test hypotheses regarding energy allocation patterns between growth, consumption, and activity rates on a multiday basis.

Defining Recovery and Detecting when IT Occurs

2003 ◽  
Vol 2003 (1) ◽  
pp. 559-564 ◽  
Author(s):  
Keith R. Parker ◽  
Alan W. Maki
Keyword(s):  
Time Series Data ◽  
Recovery Process ◽  
Statistical Analyses ◽  
Series Data ◽  
Spatial And Temporal Variation ◽  
Anthropogenic Influences ◽  
Temporal And Spatial Variation ◽  
Temporal And Spatial ◽  
Corroborative Evidence ◽  
The Impact

ABSTRACT We define recovery of a biological resource as occurring when the injured resource reaches the state it would have been, had the impact not occurred. The recovery process, and natural spatial and temporal variation affect the abundance of an injured resource and will confound to either delay or accelerate detection of recovery. The effects of natural variation can be reduced by sampling design and statistical analyses, both of which remove potentially confounding influences of temporal and spatial variation. Reference areas are useful when they respond in the same way as the impacted areas to changes in climate and anthropogenic influences. Historical data and time series data collected after the impact event are useful for detecting recovery and for assessing ecological assumptions implied in statistical analyses. Corroborative evidence from co-occurring studies of toxicity and chemistry, and supplementary data on regional changes in climate and abundance can be useful for assessing recovery. Examples from the 1989 Exxon Valdez oil spill show that full recovery of oiled shorelines and seabirds occurred in the early 1990s.

Temporal and Spatial Variation of Vegetation Coverage in Beijing-Tianjin-Hebei Metropolis Circle with MODIS Vegetation Indices Data Product

2012 ◽  
Vol 500 ◽  
pp. 123-129
Author(s):  
Ya Qing Li ◽  
Xiao Juan Li ◽  
Jian Lian ◽  
Rong Hua Wang
Keyword(s):  
Spatial Variation ◽  
Vegetation Indices ◽  
Vegetation Coverage ◽  
Spatial And Temporal Variation ◽  
Distribution Data ◽  
Temporal And Spatial Variation ◽  
Mean Values ◽  
Modis Ndvi ◽  
Data Product ◽  
Temporal And Spatial

This paper describes the temporal and spatial variation of vegetation coverage in Beijing-Tianjin-Hebei Metropolis circle using 1km MODIS vegetation indices data product (MOD13A3), and the main satellite data used in this study were MODIS NDVI and EVI data, city borderline data and DEM. After processing data with ENVI software, the time-series maps of the NDVI and EVI were drawn by ArcMap software, and the curve charts were formed by Excel. By using the temperature, rainfall data and vegetation distribution data, the spatial and temporal variation of the VI was analyzed. The results shows that the MODIS VIs varies with season, and the curves of their monthly mean values are downwards opening quadratic parabolas, with the maximum appeared in June and July. The spatial distribution of MODIS vegetation indices is positively correlated with vegetation coverage, and appeared regional characteristics. The vegetation coverage of Beijing-Tianjin-Hebei Metropolis circle has obviously increased during the past years, due to the ecological project operated in the research region.

Determinants of Diet of Brook Trout (Salvelinus fontinalis) in a Mountain Stream

1981 ◽  
Vol 38 (2) ◽  
pp. 184-192 ◽  
Author(s):  
J. David Allan
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Mountain Stream ◽  
Invertebrate Drift ◽  
Prey Choice ◽  
Feeding Rates ◽  
Predator Prey ◽  
Numerical Abundance ◽  
June July ◽  
Time Of Feeding

Feeding rates, time of feeding, and prey choice of brook trout (Salvelinus fontinalis) were studied in Cement Creek, Colorado, in 1975–77. On each of five dates from early June to late September, I collected trout at intervals over a 24-h period, along with samples of invertebrate drift and benthos. Although substantial individual variation was observed in time of feeding and prey choice, feeding during the day appeared to predominate. The period of peak feeding shifted from 18:00–22:00 in June–July to earlier hours in August–September. The average number of prey per predator declined over the season and trout relied more heavily on terrestrial forms as aquatic taxa became more rare. The weight of food eaten per day was ~3–4 × the average amount observed per stomach.The numerical abundance of prey in the diet was significantly correlated with abundance of prey in the drift. Except for a few trout which ingested large, rare prey, this was also true for prey composition by biomass. Large taxa tended to be consistently overrepresented in trout diet and small taxa underrepresented. Several prey species shifted from underrepresentation in trout diets to overrepresentation as they grew in size. Abundance and size of prey, along with individual specialization by trout presumably as a result of experience, are suggested as primary determinants of trout diet.Key words: brook trout, Salvelinus fontinalis; stream, predator-prey, aquatic insects

Effects of Chronic Exposure to Sublethal pH on Growth, Egg Production, and Ovulation in Brook Trout, Salvelinus fontinalis

1986 ◽  
Vol 43 (2) ◽  
pp. 275-280 ◽  
Author(s):  
W. H. Tam ◽  
P. D. Payson
Keyword(s):  
Brook Trout ◽  
Egg Production ◽  
Salvelinus Fontinalis ◽  
Experimental Period ◽  
The Body ◽  
Oocyte Development ◽  
Control Fish ◽  
Ph Values ◽  
Body Weights ◽  
The Mean

Hatchery-reared brook trout (Salvelinus fontinalis) were maintained in the laboratory at mean pH values of 7.34, 5.56, 5.16, and 4.48 from early February to early December. At pH 4.48, the mean growth rates of males were uniformly lowered during the entire experimental period. Among females, growth was inhibited during the first 5 mo, but their rate of weight gain recovered during the period of rapid oocyte development. At the end of the experiment, the body weights of both male and female fish in pH 5.16 and 4.48 were only 70.70–77.34% of the control fish at pH 7.34. Growth was not affected by exposure to pH 5.56. Rapid oocyte development occurred simultaneously over all pH groups in June, suggesting that the initiation of gametogenesis was not affected over the range of pH tested, the number of eggs produced was significantly correlated to body weight; consequently the number of eggs produced by the smaller pH 5.16–4.48 females was reduced. Ovulation was also significantly delayed in the acidic groups.

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