The impact of trout on galaxiid fishes in New Zealand

摘要: Compared with the effect of invaders on native terrestrial fauna New Zealand, interactions between fishes and introduced trout (sports fish in genera Salmo, Oncorhynchus Salvelinus) are less well known there have been fewer efforts to remedy their effects. Trout caused widespread reductions distribution abundance galaxiid fishes, a family dominated by threatened species. The effects most severe non-diadromous species (those lacking marine migratory stage), which commonly eliminated from streams trout. Galaxiid populations lakes, those 'whitebait' stages, also affected, but extent impacts understood. mechanisms controlling negative fish, how environment modifies interactions, will be important for future management. Experiments field comparisons indicate size-specific predation is main driver interactions. Large (> 150 mm long) do greatest damage small galaxiids adult sizes < at risk. fry stage particularly vulnerable. Despite production some trout-invaded reaches, often no survive making them population 'sinks' that must sustained dispersal. associated changes behaviour alterations stream benthic communities. However, growth fecundity little studied. Recent work indicates habitat conditions, especially floods, low flows natural acidity, can mediate trout-galaxiid We argue managers should more proactive response plight galaxiids, we identify avenues research benefit conservation activities future.