Data from: A global synthesis of environmental enrichment effect on fish stress

The stress-coping ability (SCA) is one of the core aspects of fish welfare
and is of vital importance for fish production in the aquaculture industry
and for fish fitness in hatchery release. Environmental enrichment (EE), a
method of introducing external stimuli into the husbandry environment, has
been recently proposed to improve fish SCA, but the present experimental
evidence is mixed and the reasons for these discrepancies are unclear.
Here, we conducted a global meta-analysis using a data set that consists
of 1786 cases from 107 studies across 42 fish species to solve this
problem. Overall, we found that enriched fish had significantly higher SCA
than control fish, reflected in either basal stress levels or stress
responses. Meta-regression analyses showed that specific subgroups of
enrichment type, fish developmental stage, stress category, stress
duration, stress place, sample tissue, and indicator system showed
significant positive EE effects on SCA. Multi-model inference indicated
that the indicator system, fish developmental stage, stress
characteristic, and enrichment mode are important drivers for the high
heterogeneity among effect sizes. These results highlight the importance
of introducing EE into the rearing systems, which will not only increase
the welfare of aquaculture fish but also improve the ecological
adaptability of released fish. The comprehensive knowledge obtained in
this analysis will provide insight into fish ontogenetic plasticity and
its responses to EE and have important implications for improving the
production cycle in fish aquaculture and fisheries conservation.