Interspecific association of brown trout (Salmo trutta) with non-native brook trout (Salvelinus fontinalis) at the fry stage

• The introduction of non-native brook trout (Salvelinus fontinalis) in Europe has led to displacement and decreasing populations of native brown trout (Salmo trutta). Some studies have found that brown trout shift to a diet niche similar to brook trout when the two species live in sympatry, which conflicts with the competitive exclusion principle. A change in feeding niche may be a sign of early interspecific association and social learning, leading to behavioral changes. As a first step to address this possibility, it is essential to assess the interspecific association between the species during the early ontogenetic life stages. In this study, we therefore assess whether juvenile brown trout associate with non-native juvenile brook trout to the same extent as with conspecifics by setting up two experiments: (i) a binomial choice test allowing visual and chemical cues to estimate the species specificity of group preference, and (ii) an association test without physical barriers to estimate the degree of association of a focal brown trout with a group of either conspecifics or heterospecifics. In experiment (1), we found that focal juvenile brown trout preferred to associate with the stimuli groups and did not discriminate either against conspecific or heterospecific groups. Furthermore, more active individuals showed stronger preference for the stimuli group than less active ones, regardless of species. In experiment (2), we found that brook trout groups had a tighter group structure than brown trout groups, and that focal brown trout showed stronger association with brook trout than with brown trout. These results indicate that brown trout may associate with brook trout at an early life stage, which would allow for interspecific social learning to occur. Future studies should look closer into causes and consequences of interspecific association and social learning, including potential effects on the phenotype selection in brown trout populations.

Ämnesord

SAMHÄLLSVETENSKAP  -- Psykologi -- Psykologi (hsv//swe)

SOCIAL SCIENCES  -- Psychology -- Psychology (hsv//eng)

SAMHÄLLSVETENSKAP  -- Psykologi (hsv//swe)

SOCIAL SCIENCES  -- Psychology (hsv//eng)

NATURVETENSKAP  -- Biologi -- Zoologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Zoology (hsv//eng)

Nyckelord

brook trout

brown trout

interspecific association

juvenile

Salmo trutta

Salvelinus fontinalis

fresh-water fishes

3-spined sticklebacks

leucaspius-delineatus

population regulation

species replacement

social information

foraging

behavior

selection

guppies

introductions

Psychology

Behavioral Sciences

Zoology

pulation biology

jul 17-21

1989

aberdeen

scotland

v35

p91

evassus b

1979

aquaculture

v17

p113

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