scholarly journals Bioenergetic calculations evaluate changes to habitat quality for salmonid fishes in streams treated with salmon carcass analog

2016 ◽  
Vol 73 (5) ◽  
pp. 819-831 ◽  
Author(s):  
Ernest R. Keeley ◽  
Steven O. Campbell ◽  
Andre E. Kohler
Keyword(s):  
Habitat Quality ◽  
Invertebrate Drift ◽  
Physical Habitat ◽  
Net Energy ◽  
Energy Availability ◽  
Salmonid Fishes ◽  
Nutrient Supplementation ◽  
Habitat Features ◽  
Net Energy Intake ◽  
Salmon Carcass

Nutrient supplementation in oligotrophic streams is proposed as a means of mitigating losses of marine-derived subsidies from declining or extirpated populations of anadromous fishes. One of the central predictions of nutrient addition is an increased production of fish through bottom-up increases in invertebrate abundance. Such changes in food availability may increase growth and production rates for stream fishes by increasing habitat quality. In this study we apply bioenergetic calculations to estimate changes to habitat quality based on predicted increases in net energy intake. We compared invertebrate drift abundance and estimated changes in energy availability in streams treated with salmon carcass analog versus untreated controls. Our results revealed a two- to threefold increase in invertebrate drift abundance following the addition of salmon carcass analog; however, this effect appeared to be short-term. Measures of the energetic profitability of stream habitat for salmonid fishes revealed small, yet significant, increases in net energy availability in streams that received analog additions, but only after controlling for differences in physical habitat features such as temperature and stream flow.

Bioenergetic assessment of habitat quality for stream-dwelling cutthroat trout (Oncorhynchus clarkii bouvieri) with implications for climate change and nutrient supplementation

2010 ◽  
Vol 67 (2) ◽  
pp. 371-385 ◽  
Author(s):  
Amy R. Jenkins ◽  
Ernest R. Keeley
Keyword(s):  
Climate Change ◽  
Habitat Quality ◽  
Cutthroat Trout ◽  
High Growth ◽  
Invertebrate Drift ◽  
Suitable Habitat ◽  
Physical Habitat ◽  
Net Energy ◽  
Bioenergetic Model ◽  
Oncorhynchus Clarkii

We used a bioenergetic model to determine if cutthroat trout ( Oncorhynchus clarkii bouvieri ) abundance was related to net energy intake rates (NEI) and the proportion of suitable habitat and to evaluate potential changes in habitat quality due to climate change and stream fertilization efforts. We conducted monthly sampling of cutthroat trout, invertebrate drift, and physical habitat features in pool and riffle habitats. Fish in this study selected foraging positions that enabled them to maximize NEI, and most fish were capable of sustaining high growth rates from July to September. Mean NEI and the proportion of suitable habitat at sites were greater in pools relative to riffle habitats and declined from July to October, primarily due to a decline in temperature over the four months. Cutthroat trout biomass was significantly related to NEI and the proportion of suitable habitat at a site. Model simulations indicated that climate change might reduce habitat quality for small-bodied trout, while extending the growing season for larger fish. Increased food abundance provided only marginal changes to model outcomes, whereas reductions in food significantly reduced habitat quality.

Linking time budgets to habitat quality suggests that beavers (Castor canadensis) are energy maximizers

2016 ◽  
Vol 94 (10) ◽  
pp. 671-676 ◽  
Author(s):  
Daniel Gallant ◽  
Lisa Léger ◽  
Éric Tremblay ◽  
Dominique Berteaux ◽  
Nicolas Lecomte ◽  
...  
Keyword(s):  
Habitat Quality ◽  
Time Budget ◽  
Castor Canadensis ◽  
Optimal Foraging Theory ◽  
Foraging Theory ◽  
Limiting Factors ◽  
Future Research ◽  
Net Energy ◽  
Net Energy Intake ◽  
Infrastructure Maintenance

According to optimal foraging theory, consumers make choices that maximize their net energy intake per unit of time. We used foraging theory as a framework to understand the foraging behaviour of North American beavers (Castor canadensis Kuhl, 1820), an important herbivore that engineers new habitats. We tested the hypothesis that beavers are energy maximizers by verifying the prediction that they allocate time to foraging activities independently of habitat quality in Kouchibouguac National Park of Canada in New Brunswick, where nearly five decades of unabated colonization by beavers led to family units established in habitats of varying quality. We observed the behaviour of 27 beavers at seven ponds from May to August 2001, at dusk and dawn. Habitat quality did not influence time that beavers allocated to foraging. This finding supported our hypothesis. The only factor in the best model explaining time spent foraging was the progression of spring and summer seasons (weekly periods). Limiting factors such as infrastructure maintenance and intermittent reactions to danger remain poorly understood for this important herbivore. Future research should focus on establishing the importance that habitat quality (food availability) and environmental stress (weather, predators) have on shaping its time budget and, consequently, its survival and reproductive success.

EFFECTS OF CORRECTING FOR FEEDING LEVELS ON ESTIMATES OF GENETIC PARAMETERS OF MILK YIELD AND COMPOSITION

1976 ◽  
Vol 56 (3) ◽  
pp. 523-529 ◽  
Author(s):  
A. K. W. TONG ◽  
B. W. KENNEDY ◽  
J. E. MOXLEY
Keyword(s):  
Energy Intake ◽  
Milk Fat ◽  
Genetic Parameters ◽  
Genetic Relationships ◽  
Protein Yield ◽  
Net Energy ◽  
Yield Traits ◽  
Genetic And Phenotypic Correlations ◽  
Net Energy Intake ◽  
Quadratic Effects

A total of 13,561 Holstein 305-day lactation records were studied to examine the effects of correcting records for linear and quadratic effects of 305-day net energy intake from silage, hay, pasture and meal feeding on estimates of genetic parameters of milk, fat and protein yield and fat and protein percent. Correcting records for net energy intake reduced variances of yield traits, but had little effect on composition trait variances. When expressed as a percentage of the total variance, the relative importance of sire and sire–herd components were unchanged using corrected records, and heritabilities, except for that of protein yield, were unaltered. Cow components of yield traits were reduced relative to other components after records were corrected for feeding levels. Consequently, repeatabilities were reduced as well, suggesting that a large portion of the permanent environmental effects on yield traits may be of nutritional origin. Genetic and phenotypic correlations between yield traits were also reduced appreciably after records were corrected for feed intake. Genetic relationships between milk, fat and protein yield may not be as great as commonly believed.

scholarly journals Weaning affects lipoprotein lipase activity and gene expression in adipose tissues and in masseter but not in other muscles of the calf

2001 ◽  
Vol 86 (4) ◽  
pp. 433-441 ◽  
Author(s):  
Jean-François Hocquette ◽  
Benoît Graulet ◽  
Michel Vermorel ◽  
Dominique Bauchart
Keyword(s):  
Gene Expression ◽  
Lipoprotein Lipase ◽  
Skeletal Muscles ◽  
Contractile Activity ◽  
Net Energy ◽  
Mrna Levels ◽  
Mammal Species ◽  
Adipose Tissues ◽  
Net Energy Intake ◽  
Rate Limiting

The nutritional and physiological modifications that occur during the weaning period induce adaptations of tissue metabolism in all mammal species. Among the adaptations due to weaning in ruminants, the regulation of lipoprotein lipase (LPL) activity, one of the rate-limiting steps of fatty acid utilization by tissues, was still unknown. The present study aimed at comparing LPL activity and gene expression in the heart, seven skeletal muscles and three adipose tissue sites between two groups of seven preruminant (PR) or ruminant (R) calves having a similar age (170 d), similar empty body weight (194 kg) at slaughter, and similar net energy intake from birth onwards. Triacylglycerol content of adipose tissues was 16 % lower in R than in PR calves, (P<0·01). This could be partly the result from a lower LPL activity (-57 %, P<0·01). LPL mRNA levels were also lower in R calves (-48 % to -68 %, P<0·01) suggesting a pretranslational regulation of LPL activity. Activity and mRNA levels of LPL did not differ significantly in the heart and skeletal muscles except in the masseter in which LPL activity and mRNA levels were higher (+50 % and +120 % respectively, P<0·01) in the R calves. Regulation of LPL in masseter could be explained by the high contractile activity of this muscle after weaning due to solid food chewing. In conclusion, weaning in the calf affects LPL activity and expression in adipose tissues, but not in skeletal muscles except the masseter.

Fish Habitat: Essential Fish Habitat and Rehabilitation

1999 ◽  
Keyword(s):  
Lake Erie ◽  
Habitat Management ◽  
Fish Habitat ◽  
Learning By Doing ◽  
Suitable Habitat ◽  
Physical Habitat ◽  
Fish Stocks ◽  
Habitat Features ◽  
Fish Habitats

<em>Abstract.—</em> The quality and quantity of habitats determine ecosystem productivity. Hence, they determine the potential fish productivity that sustains the fish harvests extractable from freshwaters and seas. Efforts to conserve and protect fish habitats are frustrated by key unanswered questions: which habitat types and how much must be protected to ensure natural self-sustaining fish stocks? Minns and Bakelaar presented a prototype method for assessing suitable habitat supply for fish stocks in Lake Erie, an analysis that can be used to address conservation issues. Here, the method is refined and extended, taking the assessment of habitat supply for pike <em>Esox lucius </em> in the Long Point region of Lake Erie as a case study. As with the previous study, much emphasis is placed on “learning by doing.” Because available inventories of habitat features are coarse and incomplete, improved guidelines for estimating habitat supply are expected from these prototype studies. The habitat supply method previously presented by Minns and Bakelaar is elaborated in three ways here: (1) the basic physical habitat assessment is derived from a remote-sensing inventory database; (2) methods of quantifying the thermal regime and integrating it with other habitat elements are examined; (3) habitat supply estimates are used in a pike population model, and pike biomass and production are simulated for the Long Point region of Lake Erie and then compared with available records. The roles of error and uncertainty are examined for all elements in the estimation and application of suitable habitat supply values. There is potential for supply measurement and analysis to guide fish habitat management.

scholarly journals Electronic feeding behavioural data as indicators of health status in dairy calves

2016 ◽  
Vol 55 (2) ◽  
pp. 159-168 ◽  
Author(s):  
D. Johnston ◽  
D.A. Kenny ◽  
M. McGee ◽  
S.M. Waters ◽  
A.K. Kelly ◽  
...  
Keyword(s):  
Health Status ◽  
Feeding Behaviour ◽  
Dairy Calves ◽  
Milk Replacer ◽  
Net Energy ◽  
Calf Health ◽  
Holstein Friesian ◽  
Net Energy Intake ◽  
Clinical Measurements ◽  
Calf Rearing

AbstractThe objectives of this study were (i) to characterise clinical health in dairy calves on an Irish research farm during the artificial calf-rearing period and (ii) to determine whether calves’ pre-weaning intakes and feeding behaviour, recorded by electronic calf feeders, changes in response to incidents of bovine respiratory disease (BRD). Holstein-Friesian (H-F) and Jersey (J) calves were fed by automatic milk replacer (MR) and concentrate feeders. Feeding behaviour, including MR consumption, drinking speed, number of rewarded and unrewarded visits to the feeder as well as concentrate consumption, was recorded by the feeders. A modified version of the Wisconsin calf health scoring criteria chart was used to score calves’ clinical measurements and identify incidences of BRD. Thus, 40% of calves were found to have at least one incident of BRD. Feeding behaviour was altered during incidents of BRD. The number of unrewarded visits to the feeder was reduced, by approximately four visits, for calves with BRD during the 3 d prior to the identification of BRD(P< 0.05) and tended to be reduced during the 7 d following the identification of BRD(P= 0.05), compared with healthy calves. Additionally, calves with BRD had a tendency for reduced net energy intake (approximately 8%) during the 3 d prior to the identification of BRD, compared with healthy calves. Therefore, calf feeding behavioural data, recorded by electronic feeders during the pre-weaning period, can indicate cases of BRD.

Position Choice by Drift-Feeding Salmonids: Model and Test for Arctic Grayling (Thymallus arcticus) in Subarctic Mountain Streams, Interior Alaska

1990 ◽  
Vol 47 (10) ◽  
pp. 2039-2048 ◽  
Author(s):  
Nicholas F. Hughes ◽  
Lawrence M. Dill
Keyword(s):  
Energy Intake ◽  
Water Depth ◽  
Focal Point ◽  
Water Velocity ◽  
Net Energy ◽  
Intake Rate ◽  
Arctic Grayling ◽  
Thymallus Arcticus ◽  
Net Energy Intake ◽  
Energy Intake Rate

We develop a model to predict position choice of drift-feeding stream salmonids, assuming a fish chooses the position that maximizes its net energy intake rate. The fish's habitat is represented as a series of stream cross-profiles, each divided into vertical strips characterized by water depth and velocity. The fish may select a focal point in any of these strips, and include several neighbouring strips in its foraging area. The number of prey the fish encounters depends on its reaction distance to prey, water depth, and water velocity; the proportion of detected prey the fish is able to capture declines with water velocity. The fish's net energy intake rate is its gross energy intake rate from feeding minus the swimming cost calculated by using water velocity at the fish's focal point. There was a close match between the positions predicted by this model and those chosen by solitary Arctic grayling (Thymallus arcticus) in the pools of a mountain stream in Alaska.

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