Behavioural Adjustment of Population Density to Available Food by Juvenile Atlantic Salmon

Symons, Philip E. K.

doi:10.2307/3438

Cited by 87 publications

(34 citation statements)

References 15 publications

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“…In fact, when they kept tish density constant, territory size did not change in response to changing food abundance (Slaney & Northcote 1974). Symons (1971) and Dill (1978b) likewise found no change in territory size with changing food abundance in either Atlantic salmon or coho salmon, respectively. We conclude from this that there is little, if any, evidence to support the prediction of an inverse relationship between territory size and food abundance.…”

Section: Discussionmentioning

confidence: 66%

“…However, previous studies of these in salmonids have been somewhat limited, with conflicting results (see Cole & Noakes 1980). Some studies have shown a decrease in territorial aggression and size of territories with an increase in food (Symons 1968, Slaney & Northcote 1974, Mason 1976), but others have found no change in these measures with changes in food supply (Symons 1971, Dill 1978b. Our study was designed to determine how changes in water current velocity, fish numbers (density) and food ration affect territory size and shape, as well as levels of agonistic behaviour in juvenile brook charr.…”

Section: Introductionmentioning

confidence: 94%

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Environmental influences on territoriality of juvenile brook charr, Salvelinus fontinalis, in a stream environment

McNicol

Noakes

1984

Environ Biol Fish

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SynopsisJuvenile brook chart-, Salvelinus fontinalis, defending territories in a laboratory stream channel changed their defensive tactics when fish numbers or water current velocity were increased. The associated increase in energy costs of territorial defense were apparently reduced by using relatively more lateral displays and fewer chases to repel intruders, and by decreasing territory size. Territory size tended to increase with food ration, although levels of aggression were not affected. These results emphasize the importance of energetic considerations in territoral defense in these fish, and are discussed in terms of current hypotheses regarding the resource base for territoriality.

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Section: Discussionmentioning

confidence: 66%

Section: Introductionmentioning

confidence: 94%

Environmental influences on territoriality of juvenile brook charr, Salvelinus fontinalis, in a stream environment

McNicol

Noakes

1984

Environ Biol Fish

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“…The concept that food and space regulate the abundance of stream salmonids (Chapman 1966;Symons 1971 ) has substantial support from studies on small stable streams where unpredictable abiotic influences, such as floods and droughts, are rare (Elliott 1987(Elliott , 1989Grant & Kramer 1990;Titus 1990). There was no relationship between the spatial distribution of juvenile brown trout and the distribution of benthic invertebrate food in the Kakanui River.…”

Section: Correlation Between Relative Density and Foodmentioning

confidence: 99%

Spatial and temporal variation in the relative density and size of juvenile brown trout in the Kakanui River, North Otago, New Zealand

Hayes

1995

New Zealand Journal of Marine and Freshwater Research

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Spatial and temporal variation in relative density of 0+ and 1+ brown trout was examined over three summers in the Kakanui River, North Otago, New Zealand. Both 0+ and 1+ trout were distributed throughout the river. Spatial variation in relative density was much higher than annual variation. Within years, relative density of 0+ brown trout varied by 5 to 92 times between sites (mean coefficient of variation, CV = 1.08) and of 1+ trout by 18 to 84 times between sites (CV = 1.13). Mean relative density of 0+ brown trout varied by 1.5 to 2.0 times between years (CV = 0.35) and of 1+ trout by 3.6 to 23.2 times between years (CV = 0.96). The pattern of 0+ trout spatial distribution was not closely related to the distribution of redds (which also were distributed throughout the river) and not related to the distribution of benthic invertebrate food. By their second summer, most trout occupied the middle and lower reaches of the river. Mean length of both 0+ and 1+ trout increased with distance downstream. Floods greater than 290 m 3 s -1 , and with a return period of 4 years, during the late incubation and early fry stages (August-November) were associated with impaired recruitment, yet a large flood (816 m 3 s -1 ) in March 1994 had no apparent effect on the survival of 0+ trout 80-100 mm in length.M 94042

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“…Nonetheless, research on a presumed optimal size of salmonid territory which would be linked to the quantity of food available proved inconclusive (Slaney and Northcote, 1974;Symons, 1971), except when Dill et al (1981), studying the coho salmon, found a significant inverse relation between territorial size and the quantity of benthic food inside the territory. Yet they were unable to identify the same relation when food was floating above the territories of the subjects.…”

Section: Discussionmentioning

confidence: 99%

Social and spatial structure in brook chars (Salvelinus fontinalis) under competition for food and shelter/shade

Caron

Beaugrand

1988

Behavioural Processes

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Salmonids, outside their reproductive period, are seen to have two types of territory called "territorial mosaic" and "partial territory". The first aspect of this research aimed at identifying the type of territory established by mature brook chars in artificial streams. After this, the biological value of spacing out was studied with regard to two resources: food, and shelter/shade which gives protection. Three 5 X 1 X 1 m artificial streams were built on the edge of a natural brook which provided a continuous water supply. One hundred and fifty mature brook chars (Salvelinus fontinalis) taken from that brook were distributed into 30 colonies with 5 members apiece. Three experimental conditions were created, and 10 colonies were submitted to each of these. In the first experimental condition, the quality of shelter/shade differed in 3 sectors of the artificial streams, whereas the quantity of food remained the same for all 3. In the second experimental condition, the quality of shelter/shade was identical, while the quantity of food differed in the 3 sectors. In the last condition, conflict was created: the fish had to choose between an area which offered excellent shelter/shade but no food, one which provided ample nourishment but no shelter/shade, and one in which all those resources were present at intermediate levels. Observation of the 30 colonies revealed "partial territory" in all cases. These corresponded to more or less complete aggressive-dominance hierarchies. Almost every alpha established territory, and the number of territorial individuals progressively decreased throughout inferior ranks. Alphas had exclusive use of their territory. Lower-ranking individuals successfully defended their territory against their subordinates, but were unable to drive away higher-ranking conspecifics. Overall results also indicated that the highest-ranking brook chars in the aggressive-dominance hierarchies more frequently established their territories in sectors of the streams with good shelter/shade than in sectors with good alimentary conditions.

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Behavioural Adjustment of Population Density to Available Food by Juvenile Atlantic Salmon

Cited by 87 publications

References 15 publications

Environmental influences on territoriality of juvenile brook charr, Salvelinus fontinalis, in a stream environment

Environmental influences on territoriality of juvenile brook charr, Salvelinus fontinalis, in a stream environment

Spatial and temporal variation in the relative density and size of juvenile brown trout in the Kakanui River, North Otago, New Zealand

Social and spatial structure in brook chars (Salvelinus fontinalis) under competition for food and shelter/shade

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