Assessing environmental correlates of fish movement on a coral reef

Abstract

Variation in dispersal and movement patterns of coral reef fishes is likely linked to changes in environmental conditions. Monitoring in situ environmental parameters on coral reefs in conjunction with the movements of fishes can help explain the relationship between exploited populations and their environment. Sixty adult Lethrinus miniatus were acoustically tagged and monitored along a coral reef slope for up to 1 yr. Individuals occurred more often on the reef slope during days of cooler temperatures, suggesting a thermal tolerance threshold may exist. Results indicate that individuals responded to elevated temperatures by moving away from the reef slope to deeper adjacent habitats, thus shifting their position in the water column to remain at a preferred temperature. Space use within the water column (vertical activity space) was not influenced by environmental parameters or fish size, but this result was possibly influenced by use of deeper habitat outside the acoustic array that was not monitored. With elevation of ocean temperature, L. miniatus may need to adapt to warmer waters or disperse into cooler habitats, by either shifting their distribution deeper or towards higher latitudes. Identifying key environmental drivers that affect the distribution of reef fishes is important, and may allow managers to predict the effect of these changes on exploited species.

Environmental drivers of diurnal visits by transient predatory fishes to Caribbean patch reefs

“…The focus of this study was on providing new insights into the variability of visits by transient predators to patch reefs, but these data also provide indications of the potential effects of environmental change. Firstly, temperature is likely to be at least partly causing the seasonal variation seen in some of the species and warmer sea‐surface temperatures under global climate change scenarios may affect the movement of transient predators (Currey et al ., ). The consequences on fish abundances of clearing mangrove nursery and foraging habitats have frequently been stated (Valiela et al ., ) and the present study also suggests that changes to the distribution of transient predators may occur if inshore habitat connectivity is affected by coastal development.…”

Climatic conditions and nursery habitat quality provide indicators of reef fish recruitment strength

“…Thus, fish abundances can be closely linked to patches that best match their immediate habitat requirements, explaining why the best habitat predictors of juvenile abundance are during the winter, when this size class is most prevalent. Adult lethrinids are known to move when environmental conditions become unfavorable (Currey et al ) and have average home ranges of 8.5 km 2 at Ningaloo (Pillans et al ). Although recruits may be relatively site‐attached, young fish could be capable of moving among patches to find more suitable habitat, potentially uncoupling local recruitment and juvenile abundance.…”

Importance of outer reef slopes for commercially important fishes: implications for designing a marine protected area in the Philippines

“…Currey et al [37] reported that the abovementioned 26 acoustically tracked Lethrinus miniatus tended to occur more often on the southern Great Barrier Reef slope when water temperature was cooler. Further study is needed to reveal their depth-use patterns in more detail by increasing the number of tracked fish and by specifying the purpose for visiting deeper (>30 m) areas.…”