scholarly journals Implications of territory size for the measurement and prediction of salmonid abundance in streams

1998 ◽  
Vol 55 (S1) ◽  
pp. 181-190 ◽  
Author(s):  
JWA Grant ◽  
S Ó Steingrímsson ◽  
E R Keeley ◽  
R A Cunjak
Keyword(s):  
Atlantic Salmon ◽  
Point Of View ◽  
Food Abundance ◽  
Effective Density ◽  
Sampling Unit ◽  
Territory Size ◽  
Salmonid Fishes ◽  
Age Classes ◽  
Order Of Magnitude ◽  
Habitat Saturation

Information about territory size is useful for both the measurement and prediction of salmonid abundance. Percent habitat saturation (PHS), the percentage of the stream area occupied by the territories of salmonid fishes, is a better measure of abundance than population density because the former integrates the effects of (a) several age-classes or species in a stream, and (b) variation in growth rate or sampling date. "Effective density" or "effective PHS," calculated by weighting crude density (no.·m-2) or PHS by the number of organisms in the sampling unit, more accurately reflects density from the organism's point of view than does crude density or PHS. Effective density and PHS of Atlantic salmon (Salmo salar) in Catamaran Brook, New Brunswick, increased by 0.4 fish per m2 and 4%, respectively, for each order of magnitude decrease in the area of the sampling unit. Literature data suggested that territory size is inversely related to food abundance and can be used to predict changes in salmonid abundance that accompany changes in food abundance. The allometry of territory size was a better predictor of the decline in density of a cohort of Atlantic salmon in Catamaran Brook than the allometry of metabolic requirements.

Food Abundance, Intruder Pressure, and Body Size as Determinants of Territory Size in Juvenile Steelhead Trout (Oncorhynchus Mykiss)

Behaviour ◽  
1998 ◽  
Vol 135 (1) ◽  
pp. 65-82 ◽  
Author(s):  
◽  
Keyword(s):  
British Columbia ◽  
Body Size ◽  
Atlantic Salmon ◽  
Oncorhynchus Mykiss ◽  
Food Abundance ◽  
Territory Size ◽  
Invertebrate Drift ◽  
Steelhead Trout ◽  
Daily Ration ◽  
Fish Size

AbstractWe observed the behaviour of juvenile steelhead trout (Oncorhynchus mykiss) in two rivers in British Columbia, Canada, to determine the importance of invertebrate drift abundance, intruder pressure, and body size of territory holders as correlates of territory size. Territory size increased with increasing fish size, but fish smaller than 5 cm had relatively large territories for their body size, in comparison to fish that were larger than 5 cm in length. After statistically controlling for the effect of body size, territory size was inversely related to the abundance of drifting invertebrates. Territory size was not related to the number of intrusions observed on a territory per hour, but was inversely related to local fish density, a second measure of intruder pressure. Steelhead trout appear to defend territory areas that are most similar in size to juvenile Atlantic salmon. This study provides evidence that stream-dwelling salmonids scale territory size to body size in a manner that allows them to capture a maximum daily ration of food on their territories.

Female Choice in Middendorff's Grasshopper-Warbler (Locustella Ochotensis)

The Auk ◽  
1986 ◽  
Vol 103 (4) ◽  
pp. 694-700 ◽  
Author(s):  
Hisashi Nagata
Keyword(s):  
Mate Choice ◽  
Female Choice ◽  
Morphological Characteristics ◽  
Female Mate Choice ◽  
Food Abundance ◽  
Territory Size ◽  
Territory Quality ◽  
Female Mate ◽  
Nest Sites ◽  
Grasshopper Warbler

Abstract Morphological and territorial factors that influence female mate choice were examined in the monogamous Middendorff's Grasshopper-Warbler (Locustella ochotensis) on an islet near Fukuoka, Japan. I assumed that pairing date corresponded with female mate choice. Pairing date was correlated with both territory size and food abundance but was not correlated with selected morphological characteristics of males. Territorial quality was assumed to be correlated with territory size because preferable food resources and nest sites were distributed randomly. I conclude that female mate choice was influenced by territory quality rather than by the morphological characteristics of males.

scholarly journals Objective determination of the sea age of Atlantic salmon from the sizes and dates of capture of individual fish

2010 ◽  
Vol 68 (1) ◽  
pp. 130-143 ◽  
Author(s):  
Philip J. Bacon ◽  
William S. C. Gurney ◽  
Eddie McKenzie ◽  
Bryce Whyte ◽  
Ronald Campbell ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Fishery Management ◽  
East Coast ◽  
Probability Distributions ◽  
Age Classes ◽  
Individual Fish ◽  
Bivariate Probability ◽  
Management And Conservation ◽  
Objective Determination

Abstract Bacon, P. J., Gurney, W. S. C., McKenzie, E., Whyte, B., Campbell, R., Laughton, R., Smith, G., and MacLean, J. 2011. Objective determination of the sea age of Atlantic salmon from the sizes and dates of capture of individual fish. – ICES Journal of Marine Science, 68: 130–143. The sea ages of Atlantic salmon indicate crucial differences between oceanic feeding zones that have important implications for conservation and management. Historical fishery-catch records go back more than 100 years, but the reliability with which they discriminate between sea-age classes is uncertain. Research data from some 188 000 scale-aged Scottish salmon that included size (length, weight) and seasonal date of capture on return to the coast were investigated to devise a means of assigning sea age to individual fish objectively. Two simple bivariate probability distributions are described that discriminate between 1SW and 2SW fish with 97% reliability, and between 2SW and 3SW fish with 70% confidence. The same two probability distributions achieve this accuracy across five major east coast Scottish rivers and five decades. They also achieve the same exactitude for a smaller recent dataset from the Scottish west coast, from the River Tweed a century ago (1894/1895), and for salmon caught by rod near the estuary. More surprisingly, they also achieve the same success for rod-caught salmon taken at beats remote from the estuary and including capture dates when some fish could have been in the river for a few months. The implications of these findings for fishery management and conservation are discussed.

Microwave Activation of Homogeneous and Heterogeneous Catalytic Reactions

1997 ◽  
Vol 62 (2) ◽  
pp. 347-354 ◽  
Author(s):  
Milan Hájek
Keyword(s):  
Active Sites ◽  
Specific Effect ◽  
Point Of View ◽  
Heterogeneous Reactions ◽  
Microwave Activation ◽  
Rate Enhancement ◽  
Heterogeneous Catalytic ◽  
Order Of Magnitude ◽  
And Performance ◽  
Alkylation Reactions

Microwave heating was applied in homogeneous and in heterogeneous reactions and the results were compared from the point of view of activation of chemical reactions. Reactions including the addition of halo compounds to alkenes catalyzed by copper and ruthenium complexes in different solvents and NaY zeolite catalyzed alkylation of secondary amine in the absence of solvent were studied as model reactions to compare possibilities of microwave activation of reactants and catalysts. Rate enhancement of over one order of magnitude in homogeneous reactions was caused mainly by thermal dielectric heating effect which resulted from the effective coupling of microwaves to polar solvents. Activation of reactants and catalysts was very low if any. In heterogeneously catalyzed alkylation reactions highly efficient activation of zeolite catalyst was recorded. The results indicated that the best reaction conditions were in experiments when both activation of catalyst and performance of reaction were carried out under microwave conditions. Rate enhancement was most probably caused by "hot spots" or by "selective heating" of active sites. In both homogeneous and heterogeneous reactions non-thermal activation (specific effect) was excluded.

Mechanisms underlying the increase in young-of-the-year Atlantic salmon (Salmo salar) density with habitat complexity

2008 ◽  
Vol 65 (9) ◽  
pp. 1956-1964 ◽  
Author(s):  
Oscar Venter ◽  
James W.A. Grant ◽  
Michelle V. Noël ◽  
Jae-woo Kim
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Habitat Complexity ◽  
Indirect Evidence ◽  
Growth Potential ◽  
Territory Size ◽  
Complex Environments ◽  
Atlantic Salmon Salmo Salar ◽  
Direct Support ◽  
Young Of The Year

We tested three hypotheses used to explain the increase in young-of-the-year (YOY) Atlantic salmon ( Salmo salar ) density with habitat complexity: the territory-size, predator-refuge, and foraging-benefits hypotheses. We manipulated habitat complexity in three different treatments (boulder-removed, control, and boulder-added) at eight sites in Catamaran Brook and the Little Southwest Miramichi River, New Brunswick. The density of juvenile salmon was two times higher in the boulder-added treatment than in the other treatments. Our data were consistent with the territory-size hypothesis; visual isolation was highest and territory size was smallest in the boulder-added treatment, and salmon selected microhabitats to maximize their field of view. Our results showed partial support for the predator-refuge hypothesis; salmon in the boulder-added sites were closer to cover and showed a reduced reaction distance to a novel stimulus, but did not preferentially select microhabitats closer to cover. We found no direct support for the foraging-benefits hypothesis; however, there is indirect evidence that boulders may improve the growth potential of instream habitat. Our results suggest that YOY Atlantic salmon may be attracted to complex environments for the increased cover and that the decreased visibility of these sites causes a reduction in territory size, allowing a higher density of fish.

Atlantic Salmon (Salmo salar) Stocks and Management Implications in the Canadian Atlantic Provinces and New England, USA

1981 ◽  
Vol 38 (12) ◽  
pp. 1612-1625 ◽  
Author(s):  
Richard L. Saunders
Keyword(s):  
Atlantic Salmon ◽  
New England ◽  
Salmo Salar ◽  
Environmental Influence ◽  
Function Analysis ◽  
Significant Degree ◽  
Growth Patterns ◽  
Point Of View ◽  
Atlantic Salmon Salmo Salar ◽  
Mixed Stock

This paper discusses the diversity of Atlantic salmon (Salmo salar) expressed as anatomical, physiological, and behavioral differences among stocks in the Atlantic Provinces of Canada and New England, USA. Evidence is reviewed for environmental and genetic influence on a number of stock-specific traits. Unique qualities of particular stocks are described. The loss of salmon from much of its former range is documented and discussed in relation to stock characteristics important in rehabilitation efforts. The mixed stock fisheries in Greenland and Newfoundland are considered from the point of view of interception. It is concluded that identification and management of specific stocks in the Greenland fishery are impracticable at present but that identification of North American components, using discriminant function analysis of scale growth patterns and smolt tagging, should be continued. In Newfoundland knowledge gained from tagging studies allows a significant degree of management of stocks from mainland Canada together with those from Newfoundland and Labrador. Since it is impracticable now to manage the fisheries off Greenland and Newfoundland and off the major Canadian Maritimes salmon-producing rivers—the Miramichi, Restigouche, and Saint John—in strict recognition of stocks, it is suggested that it may be possible to characterize an assemblage of like stocks from given areas and to identify and manage for these in large mixed-stock fisheries. Possible impacts of hatchery plantings are discussed in relation to prospects of success and effects on native stocks. It is concluded that we have the biological basis for evaluating likelihood of success and degree of danger to native stocks from extensive plantings of hatchery-reared juvenile salmon and that such evaluation should be conducted when embarking on projects involving use of hatchery-reared fish as part of a major salmon enhancement program in Atlantic Canada.Key words: genetics, environmental influence, rehabilitation, enhancement, interception, hatcheries, aquaculture

scholarly journals The combined impact of plant-derived dietary ingredients and acute stress on the intestinal arachidonic acid cascade in Atlantic salmon (Salmo salar)

2009 ◽  
Vol 103 (6) ◽  
pp. 851-861 ◽  
Author(s):  
Anthony Oxley ◽  
Cecile Jolly ◽  
Torunn Eide ◽  
Ann-Elise O. Jordal ◽  
Asbjørn Svardal ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Atlantic Salmon ◽  
Acute Stress ◽  
Physiological Stress ◽  
Blood Parameters ◽  
Pufa Ratio ◽  
Distal Intestine ◽  
Mediators Of Inflammation ◽  
Order Of Magnitude ◽  
Cox 2

A study was conducted to assess the effect of substituting high levels of dietary fish oil (FO) and fishmeal (FM) for vegetable oil (VO) and plant protein (PP) on the intestinal arachidonic acid (AA) cascade in the carnivorous fish species Atlantic salmon. Four diets were fed to salmon over a period of 12 months, including a control FMFO diet, with varying replacements of plant-derived ingredients: 80 % PP and 35 % VO; 40 % PP and 70 % VO; 80 % PP and 70 %VO. Subsequently, fish were examined pre- (0 h) and post- (1 h) acute stress for blood parameters and intestinal bioactive lipidic mediators of inflammation (prostaglandins). Plasma cortisol responses were greatest in the FMFO group, while 80 % PP and 70 % VO fish exhibited increased plasma chloride concentrations. The n-3:n-6 PUFA ratio in intestinal glycerophospholipids from 70 % VO groups significantly decreased in both proximal and distal regions due to elevated levels of 18 : 2n-6 and the elongation/desaturation products 20 : 2n-6 and 20 : 3n-6. Increases in n-6 PUFA were not concomitant with increased AA, although the AA:EPA ratio did vary significantly. The 40 % PP and 70 % VO diet produced the highest intestinal AA:EPA ratio proximally, which coincided with a trend in elevated levels of PGF2α, PGE2 and 6-keto-PGF1α in response to stress. PGE2 predominated over PGF2α and 6-keto-PGF1α (stable metabolite of PGI2) with comparable concentrations in both intestinal regions. Cyclo-oxygenase-2 (COX-2) mRNA expression was an order of magnitude higher in distal intestine, compared with proximal, and was significantly up-regulated following stress. Furthermore, the 80 % PP and 70 % VO diet significantly amplified proximal COX-2 induction post-stress. Results demonstrate that high replacements with plant-derived dietary ingredients can enhance COX-2 induction and synthesis of pro-inflammatory eicosanoids in the intestine of salmon in response to acute physiological stress.

Changes in the Selection of Microhabitat by Juvenile Atlantic Salmon (Salmo salar) at the Summer–Autumn Transition in a Small River

1984 ◽  
Vol 41 (3) ◽  
pp. 469-475 ◽  
Author(s):  
D. M. Rimmer ◽  
U. Paim ◽  
R. L. Saunders
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Water Depth ◽  
Water Velocity ◽  
Bottom Surface ◽  
Age Classes ◽  
Atlantic Salmon Salmo Salar ◽  
Juvenile Atlantic Salmon ◽  
Wide Range ◽  
Maximum Water

Over three summers we used direct underwater observation to examine the summer to autumn differences in seven microhabitat properties of three age-classes of juvenile Atlantic salmon (Salmo salar) in the Little Sevogle River of northeastern New Brunswick. Salmon of all three age-classes occupied a wide range of water depths during summer, but were concentrated mainly in depths of 24–36 cm. In autumn, they occurred in this range almost exclusively. The streambed stones most closely associated with the individual positions of all ages were always <20 cm in summer and mostly (84–92%) <10 cm in diameter. In autumn, all ages were associated with home stones up to 40 cm in diameter, with 65–83% of the stones exceeding 20 cm; the size of home stones selected increased with fish age in autumn. There was no apparent relationship between the water depth and home stone size distributions occupied by all age-classes and available in the stream during either summer or autumn. Summer focal water velocity (velocity at the fish's snout) was predominantly 10–30 cm∙s−1 for 0+, 10–40 cm∙s−1 for 1+, and 30–50 cm∙s−1 for 2+ salmon, but during autumn it was almost always <10 cm∙s−1 for all ages. The bottom and surface water velocities as well as the maximum water velocity within 1 m of fish stations increased with fish age during summer and autumn. At the summer–autumn transition, 0+ salmon selected higher bottom, surface, and maximum water velocities, 2+ salmon selected lower velocities, but selection by 1+ salmon remained unchanged. We view substrate size followed by water depth as the primary properties influencing stream suitability for juvenile Atlantic salmon in autumn.

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