Diel behaviour and habitat utilisation by the pearly razorfish during the spawning season

Abstract

Despite its small size, the pearly razorfish Xyrichtys novacula (Linnaeus, 1758) supports important targeted recreational and commercial fisheries. Here, we present the first data on the movements of this species obtained using acoustic telemetry in a temperate marine protected area (MPA). The results demonstrate that acoustic telemetry is well suited for behavioural studies, even in species of small size. The results confirmed previous speculations regarding the behaviour of this species, demonstrating a clear diel pattern with maximum rates of activity during the day and fewer detections at night, when the fish bury themselves in the soft bottom. X. novacula exhibited a sedentary lifestyle with limited movement. The fish occurred in an accumulated averaged area of 0.32 0.13 km 2 95% of the time (95% kernel utilisation distribution [KUD]) and in a core area (50% KUD) of 0.07 0.02 km 2 . These small areas of habitat utilisation existed independent of sex and diel behaviour. No daily migration pattern or specific resting locations were detected. The linearity index (as a proxy of site fidelity) demonstrated that the movement of X. novacula was random within a specific home range area (sedentary behaviour) rather than directional (nomadic behaviour). The observed diel pattern of behaviour confirms that this species is not vulnerable to nighttime fishing, and the small spatial scale of habitat utilisation suggests that small MPAs can be an effective management tool.