The effect of flow regime on the occurrence of interference and exploitative competition in a salmonid species, white-spotted char (Salvelinus leucomaenis)

2010 ◽  
Vol 67 (11) ◽  
pp. 1776-1781 ◽  
Author(s):  
Koh Hasegawa ◽  
Shoichiro Yamamoto
Keyword(s):  
Flow Regime ◽  
Dominance Hierarchy ◽  
Interference Competition ◽  
Food Resources ◽  
Exploitative Competition ◽  
Salvelinus Leucomaenis ◽  
Salmonid Species ◽  
Lotic Habitat ◽  
White Spotted Char

We examined the effect of flow regime on the occurrence of interference and exploitative competition in a salmonid species, white-spotted char ( Salvelinus leucomaenis ). In the lotic treatment, char showed typical consequences of interference competition (i.e., fish aggressively defended their foraging positions, and individuals occupying the most profitable positions grew fastest). In the lentic treatment, however, char behavior was consistent with exploitative competition; fish cruised over a larger area in search of food resources and showed limited aggression and no evidence of a dominance hierarchy. Our results indicate that white-spotted char showed interference competition more commonly than exploitative competition in the lotic habitat and vice versa in the lentic habitat.

Potential of habitat complexity for mitigating interference competition between native and non-native salmonid species

2008 ◽  
Vol 86 (5) ◽  
pp. 386-393 ◽  
Author(s):  
Koh Hasegawa ◽  
Koji Maekawa
Keyword(s):  
Brown Trout ◽  
Habitat Complexity ◽  
Salmo Trutta ◽  
Woody Debris ◽  
Interference Competition ◽  
Salvelinus Leucomaenis ◽  
Salmonid Species ◽  
Local Abundance ◽  
Native White ◽  
White Spotted Char

This study aimed to confirm the mitigation effect of structurally complex habitat on interspecific interference competition between native and non-native salmonid species. We evaluated the effects of habitat complexity (number and size of aggregates of large woody debris and length of undercut banks) and other habitat components that were related to the local abundance of salmonids (dimension and mean depth of pool, mean particle size, and mean current velocity) on the local abundance of native white-spotted char ( Salvelinus leucomaenis (Pallas, 1814)) in allopatry and sympatry with non-native brown trout ( Salmo trutta L., 1758). The field survey was conducted in a Japanese montane stream. The number of char in pool habitats in the allopatric area correlated positively with habitat size, i.e., pool dimension. The number of char in the sympatric area with trout was positively correlated with habitat complexity, while it was negatively correlated with number of trout. In this study, we found that structurally complex habitats might be effective in mitigating interspecific competition between native white-spotted char and non-native brown trout in a montane stream.

Microsatellite variation in white-spotted char Salvelinus leucomaenis from Sakhalin oblast

2013 ◽  
Vol 49 (9) ◽  
pp. 945-949 ◽  
Author(s):  
K. I. Afanas’ev ◽  
G. A. Rubtsova ◽  
E. G. Shaikhaev ◽  
L. A. Zhivotovskii
Keyword(s):  
Microsatellite Variation ◽  
Salvelinus Leucomaenis ◽  
White Spotted Char ◽  
Sakhalin Oblast

Behavioral and Ecological Correlates of Interference Competition among Some Hawaiian Drepanidinae

The Auk ◽  
1986 ◽  
Vol 103 (3) ◽  
pp. 564-574 ◽  
Author(s):  
John H. Carothers
Keyword(s):  
Age Differences ◽  
Dominance Hierarchy ◽  
Interference Competition ◽  
Tree Canopy ◽  
Niche Shift ◽  
Age Related ◽  
Ecological Correlates

Abstract Interference interactions were studied on the island of Maui among four species of drepanidines that fed on canopy flowers of the ohia tree (Metrosideros collina). The birds had a size-related dominance hierarchy, with ranking (most to least dominant, by location in dominance matrix) as follows: Crested Honeycreeper (Palmeria dolei), Iiwi (Vestiaria coccinea), Apapane (Himatione sanguinea), and Common Amakihi (Hemignathus virens). Immatures were subordinate to conspecific adults. Crested Honeycreepers and Iiwis defended tree-canopy territories, Apapanes were nomadic flock foragers, and Common Amakihis were secretive foragers. Dominance by Iiwis was indicated by a lack of reversals in the dominance matrix. For the top-ranked Crested Honeycreeper dominance was also reflected in greater chase or greater resulting retreat distances or both. Age-related differences in interference behavior by dominants appeared to be due to inexperience, as indicated by shorter chase distances for immatures. Among subordinates both experience and plumage could be responsible for age differences in behavior. Immatures were chased equal distances (despite closer spacing) but less often than adults, and they chose safer retreat sites. Apapanes fed in flocks in a dominant's tree. This increased a dominant's territorial costs, reduced chase frequencies, increased Apapane foraging times, and let Apapanes forage in trees from which they otherwise were excluded. Comparisons with the assemblage on the island of Hawaii suggested similar structure among the three species the two islands have in common. On Maui the bottom-ranked Common Amakihi may be more affected by interference competition, perhaps undergoing a niche shift toward greater insectivory because of an additional dominant.

Extreme life history change of white-spotted char (Salvelinus leucomaenis) after damming

2000 ◽  
Vol 57 (6) ◽  
pp. 1300-1306 ◽  
Author(s):  
Kentaro Morita ◽  
Shoichiro Yamamoto ◽  
Noboru Hoshino
Keyword(s):  
Life History ◽  
High Growth ◽  
Migratory Behavior ◽  
Transplant Experiment ◽  
Dam Construction ◽  
Low Density ◽  
Salvelinus Leucomaenis ◽  
Migration Barriers ◽  
Potential Migrant ◽  
White Spotted Char

Dam construction has serious consequences for anadromous fishes. We examined the effects of migration barriers formed following dam construction on the migratory behavior of white-spotted char (Salvelinus leucomaenis) by comparing migrants in accessible below-dam river sections with migrants in inaccessible above-dam river sections. The frequency of smolts (i.e., potential migrant) was higher for the below-dam sections than for the above-dam sections, and in contrast, the frequency of residents was higher for the above-dam sections. Above-dam sections had lower fry (age 0+) densities and consequently had higher growth rates compared with below-dam sections. A transplant experiment revealed that the majority of the below-dam fish adopted a resident strategy, as well as above-dam fish, when both had experienced the above-dam environment. We conclude that high growth as a result of low density promotes residency in the above-dam sections.

Role of visual barriers on mitigation of interspecific interference competition between native and non-native salmonid species

2009 ◽  
Vol 87 (9) ◽  
pp. 781-786 ◽  
Author(s):  
Koh Hasegawa ◽  
Koji Maekawa
Keyword(s):  
Interspecific Competition ◽  
Relative Intensity ◽  
Native Species ◽  
Salmo Trutta ◽  
Woody Debris ◽  
Interference Competition ◽  
Potential Method ◽  
Salvelinus Leucomaenis ◽  
Brown Trout Salmo Trutta ◽  
Native Salmonids

Interspecific competition is a mechanism by which native salmonids can be replaced by non-native species. According to the two-species Lotka–Volterra competition model, replacement of the native species would occur when the non-native species has a competitive advantage over the native species and interspecific competition is more intense than competition within each of the two species. However, field observations have implied that visual barriers such as woody debris may slow down the replacement by mitigating interspecific competition. Using an experimental stream with white-spotted charr ( Salvelinus leucomaenis (Pallas, 1814)) as the native species and brown trout ( Salmo trutta L., 1758) as the non-native species, this study examined aggressive actions within and between species to assess the relative intensities of interspecific and intraspecific competitons within native species and the effect of visual barriers for reducing the relative intensity. In a sympatric and no-barrier treatment where trout was the dominant species, interspecific competition occurred more intensely than intraspecific competition among native charr. However, the relative intensity of interspecific competition decreased in a sympatric and with-barrier treatment. Our results suggest that interspecific competition may contribute to the replacement of native species by more competitive, non-native species. However, restoring visual barriers is a potential method to mitigate interference interactions and may deter the replacement.

scholarly journals Is Exploitation Competition Involved in a Multitrophic Strategy for the Biocontrol of Fusarium Head Blight?

2019 ◽  
Vol 109 (4) ◽  
pp. 560-570 ◽  
Author(s):  
Sabrina Sarrocco ◽  
Fabio Valenti ◽  
Sara Manfredini ◽  
Pilar Esteban ◽  
Rodolfo Bernardi ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Fusarium Head Blight ◽  
Competitive Ability ◽  
Ecological Study ◽  
Interference Competition ◽  
Antagonistic Activity ◽  
Exploitative Competition ◽  
Head Blight ◽  
Exploitation Competition ◽  
First Time

Trichoderma gamsii T6085 was used in combination with a Fusarium oxysporum isolate (7121) in order to evaluate, in a multitrophic approach, their competitive ability against F. graminearum, one of the main causal agents of Fusarium head blight (FHB) on wheat. The two antagonists and the pathogen were coinoculated on two different natural substrates, wheat and rice kernels. Both T6085 and 7121, alone and coinoculated, significantly reduced the substrate colonization and mycotoxin production by the pathogen. The two antagonists did not affect each other. Using a metabolic approach (Biolog), we investigated whether exploitation competition could explain this antagonistic activity. The aim was to define whether the three fungi coexist or if one isolate nutritionally dominates another. Results obtained from Biolog suggest that no exploitative competition occurs between the antagonists and the pathogen during the colonization of the natural substrates. Interference competition was then preliminarily evaluated to justify the reduction in the pathogen’s growth and to better explain mechanisms. A significant reduction of F. graminearum growth was observed when the pathogen grew in the cultural filtrates of T. gamsii T6085, both alone and cocultured with F. oxysporum 7121, thus suggesting the involvement of secondary metabolites. As far as we know, this is the first time that an ecological study has been performed to explain how and which kind of competition could be involved in a multitrophic biocontrol of FHB.

Failure of physiological metrics to predict dominance in juvenile Pacific salmon (Oncorhynchus spp.): habitat effects on the allometry of growth in dominance hierarchies1Order of authors represents their contribution to the manuscript.

2011 ◽  
Vol 68 (10) ◽  
pp. 1811-1818 ◽  
Author(s):  
Travis E. Van Leeuwen ◽  
Jordan S. Rosenfeld ◽  
Jeffrey G. Richards
Keyword(s):  
Dominance Hierarchy ◽  
Pacific Salmon ◽  
Interference Competition ◽  
Fish Growth ◽  
Stream Channels ◽  
Juvenile Salmonids ◽  
Natural Stream ◽  
Mixed Support ◽  
Juvenile Pacific Salmon ◽  
Access To Food

Territoriality is one of the best examples of interference competition and generally results in larger, dominant individuals gaining preferential access to food. However, the expectation of higher growth of dominant individuals among juvenile salmonids has received only mixed support. We used outdoor semi-natural stream channels stocked with varying sizes of young of the year juvenile salmonids under high and low food rations (i) to examine the mechanisms underlying variation in the benefits of dominance and (ii) to demonstrate that inconsistencies in the apparent benefits of dominance are a logical outcome of the allometry of growth and differential energy intake among fish of different size in a dominance hierarchy. Growth of dominants exceeded that of subordinates when food was abundant, but subordinates grew faster than dominants in low food treatments and when dominant fish increased in size and approached the capacity of their habitat. In general, size disparity within a dominance hierarchy may promote higher growth of subdominants because of the lower energetic requirements of smaller individuals, and the allometry of fish growth, relative to habitat capacity, can reverse the expected growth and condition of dominant and subordinate fish.

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