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.

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.

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.

scholarly journals De novo assembly of the Brown trout (Salmo trutta m. fario) brain and muscle transcriptome: transcript annotation, tissue differential expression profile and SNP discovery

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
J. Fibla ◽  
N. Oromi ◽  
M. Pascual-Pons ◽  
J. L. Royo ◽  
A. Palau ◽  
...  
Keyword(s):  
Differential Expression ◽  
Brown Trout ◽  
Salmo Trutta ◽  
De Novo ◽  
Transcriptome Assembly ◽  
Differential Expression Analysis ◽  
Cdna Libraries ◽  
Significant Differential Expression ◽  
Reference Transcriptome ◽  
Salmonid Species

Abstract Objectives The Brown trout is a salmonid species with a high commercial value in Europe. Life history and spawning behaviour include resident (Salmo trutta m. fario) and migratory (Salmo trutta m. trutta) ecotypes. The main objective is to apply RNA-seq technology in order to obtain a reference transcriptome of two key tissues, brain and muscle, of the riverine trout Salmo trutta m. fario. Having a reference transcriptome of the resident form will complement genomic resources of salmonid species. Data description We generate two cDNA libraries from pooled RNA samples, isolated from muscle and brain tissues of adult individuals of Salmo trutta m. fario, which were sequenced by Illumina technology. Raw reads were subjected to de-novo transcriptome assembly using Trinity, and coding regions were predicted by TransDecoder. A final set of 35,049 non-redundant ORF unigenes were annotated. Tissue differential expression analysis was evaluated by Cuffdiff. A False Discovery Rate (FDR) ≤ 0.01 was considered for significant differential expression, allowing to identify key differentially expressed unigenes. Finally, we have identified SNP variants that will be useful tools for population genomic studies.

Effects of woody debris on the growth and behaviour of brown trout in experimental stream channels

1998 ◽  
Vol 76 (1) ◽  
pp. 56-61 ◽  
Author(s):  
Karl Sundbaum ◽  
Ingemar Näslund
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Woody Debris ◽  
Feeding Activity ◽  
Control Channel ◽  
Invertebrate Drift ◽  
Stream Channels ◽  
Gravel Bed ◽  
Brown Trout Salmo Trutta ◽  
Experimental Stream

We examined the effects of woody debris on the growth and behaviour of brown trout (Salmo trutta) in experimental stream channels. Two types of habitat were used in the study: a complex habitat created by placing woody debris on a gravel bed and a uniform habitat consisting of a gravel bed only. The experiment was run both outdoors with wild fish that fed on natural invertebrate drift and indoors with hatchery fish that were fed artificial food. In both treatments most of the fish lost mass. In all trials, however, the fish in the woody debris channel lost less mass than the fish in the control channel. Study of the fishes' behaviour revealed less swimming activity, less aggression, and less feeding activity in the woody debris channel than in the control channel. The results of this study indicate that the presence of woody debris decreases intraspecific competition through visual isolation, allowing fish to reduce aggressive interactions and energy expenditure.

Competition for Spawning Space Between Brown (Salmo trutta) and Rainbow Trout (S. gairdneri) in a Lake Inlet Tributary, New Zealand

1987 ◽  
Vol 44 (1) ◽  
pp. 40-47 ◽  
Author(s):  
John W. Hayes
Keyword(s):  
Rainbow Trout ◽  
New Zealand ◽  
Brown Trout ◽  
Intraspecific Competition ◽  
Salmo Trutta ◽  
Interference Competition ◽  
Experimental Section ◽  
Egg Deposition ◽  
Redd Superimposition ◽  
Spawning Success

Effect of interference competition for spawning space on spawning success of brown (Salmo trutta) and rainbow trout (S. gairdneri) was studied in the main spawning tributary of Lake Alexandrina, New Zealand. Competition was mediated through redd superimposition and severely limited the spawning success of both species. Overall spawning success, from egg deposition to fry emergence, was 2.1% for rainbow trout and 0.2% for brown trout and was dependent on time of spawning. Brown trout spawned from April to June and rainbow trout spawned from April to October. Brown trout and early spawning rainbow trout experienced poor spawning success due to severe redd superimposition by later spawning rainbows. Late spawning rainbows experienced highest spawning success. Redd superimposition by rainbow trout caused a 94% reduction in spawning success of brown trout in an experimental section of stream. Severe intraspecific competition for spawning space, through redd super-imposition, determined pattern and timing of peak rainbow fry emergence.

scholarly journals Differences in brain morphology of brown trout across stream, lake, and hatchery environment

2021 ◽  
Author(s):  
Libor Závorka ◽  
J. Koene ◽  
Tiffany Armstrong ◽  
Lena Fehlinger ◽  
Colin Adams
Keyword(s):  
Brown Trout ◽  
Habitat Complexity ◽  
Salmo Trutta ◽  
Brain Size ◽  
Cognitive Capacity ◽  
Brain Morphology ◽  
Physical Habitat ◽  
Omega 3 ◽  
Brown Trout Salmo Trutta ◽  
Size And Morphology

The trade-off between cognitive capacity and developmental costs drive brain size and morphology across fish species, but this pattern is less explored at intraspecific level. Physical habitat complexity has been proposed as a selection pressure on cognitive capacity that shapes brain morphology of fishes, but development of brain is also inherently linked to supply of energy and nutrients, particularly of omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA). In this study, we compared brain morphology of brown trout Salmo trutta from stream, lake, and hatchery environments, which differ in physical complexity and availably of dietary n-3 LC-PUFA ranging from low habitat complexity and high n-3 LC-PUFA availability in hatchery to high habitat complexity and low n-3 LC-PUFA availability in streams. We found that brain size, and size of optic tectum and telencephalon differed across the three habitats, being largest in lake fish. We suggest that these differences appeared to associate with diet quality and habitat specific behavioural adaptations rather than physical habitat complexity.

scholarly journals Spatial assemblage and interference competition of introduced Brown Trout (Salmo trutta) in a Himalayan river network: Implications for native fish conservation

2021 ◽  
Vol 24 (2) ◽  
pp. 33-42
Author(s):  
Aashna Sharma ◽  
Vineet Kumar Dubey ◽  
Jeyaraj Antony Johnson ◽  
Yogesh Kumar Rawal ◽  
Kuppusamy Sivakumar
Keyword(s):  
Brown Trout ◽  
Relative Abundance ◽  
Salmo Trutta ◽  
Propagule Pressure ◽  
Interference Competition ◽  
Fish Fauna ◽  
Native Fish ◽  
Management Actions ◽  
Snow Trout ◽  
Brown Trout Salmo Trutta

Abstract Often regarded as a potential threat to the native fish fauna worldwide, the Brown Trout (Salmo trutta), has successfully established its population in the majority of the Himalayan rivers post its introduction dating back to the eighteenth century. Over the years, the species has gained infamy as a sport fish and is considered a profitable source of income to the locals ensuing a heightened propagule pressure due to lack of appropriate management actions. No comprehensive study has been conducted to date in order to understand the mechanism by which the Brown Trout poses threat to the native fish populations. Through the present study, we could assess its competition with the native Snow Trout (Schizothorax richardsonii) to understand the spatial assemblage of both the species across space in Tirthan, a pristine high-altitude river of the western Himalaya. River Tirthan is one of the major tributaries of River Beas traversing for most of its stretch within the protected boundaries of the Great Himalayan National Park Conservation Area. A total of 108 sampling points were chosen from confluence to origin of rivers/streams, ranging from 989 to 3677msl. A total of 28 explanatory variables were recorded at each point. Overall, the Brown Trout adults were found to be greater in relative abundance (66.1%) than the Snow Trout adults (33.9%). The fingerlings of Snow Trout on the other hand, were distinctively high in relative abundance (61.9%) than those of the invasive Brown Trout (38.1%). Non-native trout showed higher abundance in the higher stream orders i.e. in the main streams while natives mostly restricted themselves to the lower order streams. Redundancy analysis (RDA) for species and environmental covariates resulted in 40.75% of constrained variance with higher eigen values for Redundancy analysis1 and Redundancy analysis2. Ward’s minimum variance clustering of Hellinger transformed data revealed sites agglomerating into six reasonable distinct subgroups with respect to species abundances. Immature individuals of non-native and native trout used similar habitat conditions, but they differed in using habitats at adult stage. Our results show a competitive dominance of Brown Trout in terms of higher abundance and maximum space utilization that highlight an urgent action for preventing its introductions to new areas. We recommend a national policy of ‘The Indian Invasive Species Act’ and management level interventions to control overstocking in the areas of established population.

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