Data from: Coral-reef fishes can become more risk-averse at their poleward range limits

As climate warms, tropical species are expanding their distribution to
temperate ecosystems where they are confronted with novel predators and
habitats. Predation strongly regulates ecological communities, and
range-extending species that adopt an effective antipredator strategy have
a higher likelihood to persist in non-native environments. Here, we test
this hypothesis by comparing various proxies of antipredator and other
fitness-related behaviours between range-extending tropical fishes and
native-temperate fishes at multiple sites across a 730 km latitudinal
range. Although some behavioural proxies of risk-aversion remained
unaltered for individual tropical fish species, in general, they became
more risk-averse (increased sheltering and/or flight initiation distance),
and their activity level decreased poleward. Nevertheless, they did not
experience a decline in body condition or feeding rate in their temperate
ranges. Temperate fishes did not show a consistently altered pattern in
their behaviours across range locations, even though one species increased
its flight initiation distance at the warm-temperate location and another
one had lowest activity levels at the coldest range location. The
maintenance of feeding and bite rate combined with a decreased activity
level and increased sheltering may be behavioural strategies adopted by
range-extending tropical fishes, to preserve energy and maintain fitness
in their novel temperate ecosystems.