Geometry for the eccentric territory

1982 ◽  
Vol 60 (7) ◽  
pp. 1776-1779 ◽  
Author(s):  
David L. G. Noakes ◽  
Richard E. McNicol
Keyword(s):  
Salvelinus Fontinalis ◽  
Concave Side ◽  
Basic Theory ◽  
Salmonid Fishes ◽  
Two Dimensional ◽  
Brook Charr ◽  
Geometric Shapes ◽  
Limiting Case

Basic theory predicts that two-dimensional territories should be circular, but results from stream-dwelling juvenile salmonid fishes appear to deviate consistently from such a shape. We present a model for cardioidal territories based on data from juvenile brook charr (Salvelinus fontinalis) and show that circles can be considered as a limiting case for cardioids. Since they are regular geometric shapes directly related to circles, but with one concave side, cardioids may be useful for some analyses of territorial data.

Do brook charr (Salvelinus fontinalis) from insular Newfoundland have different parasites than their mainland counterparts?

1991 ◽  
Vol 69 (3) ◽  
pp. 809-811 ◽  
Author(s):  
David J. Marcogliese ◽  
David K. Cone
Keyword(s):  
North America ◽  
Parasite Species ◽  
Salvelinus Fontinalis ◽  
Salmonid Fishes ◽  
Primary Reason ◽  
Brook Charr ◽  
Northeastern North America ◽  
Metazoan Parasite ◽  
The Difference ◽  
Brook Char

Based on the published literature, comparison of the metazoan parasite faunas of brook char (Salvelinus fontinalis) from freshwater localities in northeastern North America reveals that hosts in insular Newfoundland have fewer parasite species recorded from them. Of 45 parasite species or taxa, only 20 are common to the island and the mainland. Twenty-three parasite species have been reported from the mainland but not from the island, with most of the taxa being types common to non-salmonid fishes. Two species, the copepod Ergasilus luciopercarum and the digenean Tetracotyle, have been reported from charr on the island but not from the northeastern mainland. It is suggested that the primary reason for the difference in the structure of the assemblages is the lack of contact brook charr in Newfoundland have with percid, cyprinid, centrarchid, esocid, and catostomid fishes and their parasites.

Bénéfices à court terme des mouvements anadromes saisonniers pour une population d'omble de fontaine (Salvelinus fontinalis) du Nouveau Québec

1991 ◽  
Vol 48 (11) ◽  
pp. 2212-2222 ◽  
Author(s):  
Jean-François Doyon ◽  
Christiane Hudon ◽  
Roderick Morin ◽  
F. G. Whoriskey Jr.
Keyword(s):  
Water Level ◽  
Egg Size ◽  
Salvelinus Fontinalis ◽  
Condition Factor ◽  
Size At Maturity ◽  
Brook Charr ◽  
Tissue Water Content ◽  
Tissue Water ◽  
Single Population ◽  
Energetic Reserves

This study characterizes the seasonal anadromous movements of a brook charr population and compares its biological and energetic characteristics with charr spending summer in freshwaters. Downstream movements monitored at a counting fence over 3 yr were most intense in spring but occurred until fall and were positively correlated with rapid increases of water level. The timing of movements varied from year to year. Smaller charr were most subject to being swept downstream compared with freshwater residents, and most trout were concentrated near the mouth of the river. These patterns suggest that the downstream movements of charr in this system are passive. Upstream migrants had a higher condition factor and a lower tissue water content than freshwater residents, indicating that downstream movements result in a faster accumulation of energetic reserves during summer. However, the fortuitous character of anadromous migrations as well as the absence of differences in the biological characteristics (growth, size at maturity, fecundity, egg size) suggests that anadromous and resident fish belong to a single population whose yearly migrant component could be randomly determined.

Mechanisms responsible for the niche shift of brook charr, Salvelinus fontinalis Mitchill, when living sympatrically with creek chub, Semotilus atromaculatus Mitchill

1984 ◽  
Vol 62 (8) ◽  
pp. 1548-1555 ◽  
Author(s):  
Pierre Magnan ◽  
Gérard J. FitzGerald
Keyword(s):  
Laboratory Experiments ◽  
Salvelinus Fontinalis ◽  
Niche Shift ◽  
Intraspecific Aggression ◽  
Brook Charr ◽  
Semotilus Atromaculatus ◽  
High Level ◽  
Gill Raker ◽  
Creek Chub ◽  
Study Laboratory

When brook charr, Salvelinus fontinalis Mitchill, are in allopatry in oligotrophic Québec lakes, they feed largely on macrobenthic invertebrates. However, when brook charr cooccur with creek chub, Semotilus atromaculatus Mitchill, they feed largely on zooplankton. In the present study, laboratory experiments showed that creek chub were more effective than brook charr in searching for hidden, patchily distributed prey. The searching efficiency of an individual chub feeding in a group was improved through social facilitation. In contrast, the high level of intraspecific aggression observed in brook charr prevents the formation of such feeding groups. In the laboratory, brook charr were able to displace creek chub from the food source because of interspecific aggression. Data are presented showing that chub are morphologically better adapted than charr to feed on benthos (subterminal orientation of the mouth and protrusible premaxillae), while the charr are better adapted than chub to feed on zooplankton (gill raker structure). Differences in feeding behaviour, morphology, and relative abundance between these species appear to be important in the observed niche shift of brook charr in nature.

scholarly journals Maternal transfer of carbon and nitrogen to progeny of sea-run and resident brook trout (Salvelinus fontinalis)

2008 ◽  
Vol 65 (10) ◽  
pp. 2201-2210 ◽  
Author(s):  
Timothy D. Jardine ◽  
Eric Chernoff ◽  
R. Allen Curry
Keyword(s):  
New Brunswick ◽  
Early Life ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Early Life History ◽  
Maternal Transfer ◽  
Salmonid Fishes ◽  
Energy Reserves ◽  
Carbon And Nitrogen ◽  
Emergence Traps

Early-life history characteristics of sea-run and resident salmonid fishes that co-exist in sympatry are poorly understood. To assess differences in characteristics of offspring of these two strategies following their emergence to the stream, stable isotope ratios (δ13C and δ15N) were used to identify the progeny of resident and sea-run female brook trout ( Salvelinus fontinalis ) in a tributary of the Miramichi River, New Brunswick, Canada. Upon emergence, sea-run progeny captured in emergence traps were longer, heavier, and had higher carbon to nitrogen ratios (C/N, an indicator of lipid content) than resident progeny, but did not have a higher body condition. After some feeding and growth in the stream, sea-run progeny (still identifiable by their δ13C and δ15N) captured in dip-nets became longer, heavier, had higher C/N, and had higher condition than resident progeny. The proportion of fish caught in dip nets at sites where the two forms co-existed was dominated by offspring of sea-run females (sea-run = 56%, resident = 19%, unknown = 25%). These analyses suggest that offspring of sea-run, female trout benefit from maternally derived energy reserves gained at sea and thus have potential adaptive advantages over offspring of residents.

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