MEPS 619:111-124 (2019)  -  DOI: https://doi.org/10.3354/meps12953

ABSTRACT: Life-cycle diversity is the existence of alternative strategies among coexisting individuals within the same population and is an important factor in the structuring and connectivity of fish stocks. Mark-recapture data, collected along the coastline of southern Africa from 1984-2015, were used to investigate the occurrence of different movement behaviours (resident vs. wide-ranging) in 5 fishery species with contrasting life histories. A total of 88245 individuals was tagged, with recapture rates ranging from 4-27% for the 5 species. Individuals were considered resident if recaptured within 0-5 km of the release site after 365 d at liberty or wide-ranging if recaptured more than 50 km from the release site within 365 d. All species exhibited resident and wide-ranging behaviour, but 73% of observations qualified as resident. Logistic regression confirmed that species, life stage (juvenile/adult) and bioregion were significant predictors of wide-ranging behaviour, with tagged adults at lower latitudes being most inclined to undertake wide-ranging movements. A Gaussian model confirmed that species and bioregion were also significant predictors of direction and distance of wide-ranging movement, with typically resident species on the west coast behaving differently from typically migratory species on the east coast. Growth rate was greater in wide-ranging individuals, although it was only statistically significant in 2 species. Our findings provide evidence in support of movement variability being a widely used strategy in both teleosts and elasmobranchs. Diversity in movement behaviour may provide resilience at the population level and should be considered in fisheries management.

KEY WORDS: Intra-population variability · Partial migration · Ecological resilience · Fish movement · Mark-recapture · Fisheries management