Premium
Selective segregation in intraspecific competition between juvenile Atlantic salmon ( Salmo salar ) and brown trout ( Salmo trutta )
Author(s) -
Berg Ole K.,
Bremset Gunnbjørn,
Puffer Michael,
Hanssen Kjersti
Publication year - 2014
Publication title -
ecology of freshwater fish
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 55
eISSN - 1600-0633
pISSN - 0906-6691
DOI - 10.1111/eff.12107
Subject(s) - salmo , allopatric speciation , brown trout , sympatric speciation , trout , sympatry , biology , fishery , habitat , ecology , phoxinus , intraspecific competition , salmonidae , juvenile , competition (biology) , juvenile fish , fish <actinopterygii> , population , minnow , demography , sociology
Interactive segregation has been suggested as the ruling competition mechanism determining niche and niche segregation between juvenile Atlantic salmon ( Salmo salar ) and brown trout ( Salmo trutta ). Results from allopatry–sympatry observations of habitat use in both nature and in experiments were contrary to predictions derived from the interactive segregation hypothesis. Habitat use parameters under natural conditions such as distance to shore for Atlantic salmon parr were nearly identical in allopatric (mean ± SD ; 3.2 ± 1.4 m) and sympatric (3.3 ± 1.4 m) situations. Occupied water depths largely reflected available water, but water depths <15 cm were avoided by salmon parr. Under experimental conditions, habitat use of allopatric salmon was density independent and salmon size had only minor effects, with smaller fish being more likely to occur in the shallow. Habitat use of salmon in sympatry with trout did not differ from allopatric salmon habitat use, and only salmon size had minor effects on depth choice – occurrence of trout or fish density had no effect. Allopatric trout was in general more frequent in the shallow habitat than salmon. Habitat use of sympatric trout was affected by the occurrence of salmon and trout size, resulting in a higher use of the shallow habitats for small trout. To conclude, selective segregation has a dominant role in salmon habitat use (not affected by trout occurrence), whereas a mixed situation occurs in trout habitat use with elements of interactive segregation when competing with Atlantic salmon (affected by salmon occurrence).