Home range and residency of Scorpaena porcus and Scorpaena scrofa in artificial reefs revealed by fine-scale acoustic tracking

Abstract

Artificial reefs (ARs) are defined as any structures that are placed on the seafloor to protect sensitive ecosystems, enhance biodiversity, and support small-scale fisheries or diving tourism. With the recent development of fine-scale acoustic tracking, ecologists and fishery managers have gained a powerful tool to explore how exploited species behave in newly created artificial habitats. Here, we report for the first time the space used by the black scorpionfish (Scorpaena porcus) and red scorpionfish (Scorpaena scrofa), two highly important exploited species in the Mediterranean Sea that are often managed with ARs. The Vemco VR2W positioning system (VPS) was used to examine the fine-scale movement patterns (home range) and residency time of these species. S. porcus (182–271 mm total length; n = 14) and S. scrofa (252–445 mm total length; n = 7) were tracked for up to 91 d in ARs located in Edremit Bay, northern Aegean Sea, Turkey. The results revealed high site fidelity during the tracking period and high variability (among individuals) in their home range areas, which ranged from 933 m2 to 28,674 m2 (Kernel Utilization Distribution 95%) for S. porcus and from 1895 m2 to 17,487 m2 for S. scrofa, with a mean and s.d. of 9591 ± 8998 m2 and 8104 ± 6113 m2, respectively. The variability in the home range areas was explained neither by the fish length nor diel phase (day vs. night), although residency indexes suggested stronger site fidelity in large S. scrofa. While the lack of size-dependent home range behavior could be explained by the limited size of the range (imposed by the telemetry system), the lack of diel differences in their home range sizes could be explained by the ambush predatory behavior of both species. Our findings suggested that ARs may facilitate the profitability of fisheries in both species by retaining adults and enhancing recruitment of newly settled fish, as suggested by the movement patterns and habitat utilization indexes considered in this study.