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. 460: 207-220, 2012 prey (Cardinale et al. 1997, Castriota et al. 2005a, occupying a mid-trophic level within the food web (Blanco et al. 2009, Box et al. 2010. KEY WORDS: Acoustic telemetry · Continuous wavelet transform · Control tag · Home range · MPA · Protogynous hermaphrodite · Xyrichtys novacula Resale or republication not permitted without written consent of the publisherMar Ecol Prog SerSome populations of this species have been subjected to overfishing, exhibiting clear decreases in abundance and their age and size distributions as well as the size at maturation, thereby decreasing the size at sex change and affecting reproductive output (Linde & Palmer 2008). In an effort to effectively manage this species, a number of management measures have been adopted, including seasonal closures, daily bag limits and minimum sizes of hooks (e.g. Morales-Nin et al. 2010).However, the usefulness of MPAs depends on the scale of fish movement in relation to the size of the MPA (Kramer & Chapman 1999). Thus, effective MPAs must include appropriate habitats and be sufficiently large to encompass the regular movements of adult fish (i.e. their home ranges). Then, the spillover of early life stages (eggs and larvae) and the movement of adults into areas outside the MPA can only be successful (in terms of sustainability) if a stable adult population is able to persist within the protected area (Kaplan et al. 2006).Unfortunately, most management measures continue to be based on the assumption that fish populations are spatially homogeneous (Botsfo...

Population structure of the pearly razorfish, <em>Xyrichtys novacula</em> (Actinopterygii: Labridae), in sand-seagrass mosaics: spatial variation according to habitat features and sampling techniques

“…This would complicate the capacity of individuals to construct burrows and to bury and dive into the substrate. This result fits with findings from the Mediterranean Sea, where the finer the sediment the less abundant is X. novacula (Katsanevakis 2005); specifically, particle grain sizes between 0.125 and 0.250 mm are not suitable for this species (Alós et al 2012).…”

“…Individuals of this species typically display a reduced 'home range' (<0.5 km 2 ), with a small habitat use area, i.e. a sedentary life style (Alós et al 2012). This has been explained, at least during the reproductive period, by the complex social structure of X. novacula, a polygynous species with harem behaviour, where females occupy small territories and males patrol and defend (from other males) larger areas usually encompassing four to six female territories (Marconato et al 1995).…”

“…In the Mediterranean region, this fish is a highly prized species, particularly in the Balearic Islands (Box et al 2009, Alós et al 2012, where it reaches top market prices (Beltrano et al 2006). In the Canary Islands, however, captures of this fish are low, because it has never been a target for the local cuisine.…”

“…In the Canarian small-scale fisheries, it is captured incidentally through hooks, fish-traps and trammel nets that target other fish species (Franquet and Brito 1995). Along its distributional range, several aspects of the biology and ecology of X. novacula have been previously studied, including reproduction (Bentivegna and Rasotto 1987, Marconato et al 1995, Cardinale et al 1998, Candi et al 2004, juvenile morphology (Mercader 1991), age and growth patterns (Cardinale et al 1998, Battaglia et al 2010, trophic ecology (Cardinale et al 1997, Castriota et al 2005a,b, 2010, Beltrano et al 2006, and habitat use (Katsanevakis 2005, Alós et al 2012). This fish species often inhabits shallow waters (0-90 m depth, Fischer et al 1987, Franquet and Brito 1995, Froese and Pauly 2015 on sandy bottoms (Mercader 1991, Brito et al 2002, Katsanevakis 2005, Alós et al 2012, frequently adjacent to seagrass meadows and coral reefs (Schneider 1990).…”

“…Along its distributional range, several aspects of the biology and ecology of X. novacula have been previously studied, including reproduction (Bentivegna and Rasotto 1987, Marconato et al 1995, Cardinale et al 1998, Candi et al 2004, juvenile morphology (Mercader 1991), age and growth patterns (Cardinale et al 1998, Battaglia et al 2010, trophic ecology (Cardinale et al 1997, Castriota et al 2005a,b, 2010, Beltrano et al 2006, and habitat use (Katsanevakis 2005, Alós et al 2012). This fish species often inhabits shallow waters (0-90 m depth, Fischer et al 1987, Franquet and Brito 1995, Froese and Pauly 2015 on sandy bottoms (Mercader 1991, Brito et al 2002, Katsanevakis 2005, Alós et al 2012, frequently adjacent to seagrass meadows and coral reefs (Schneider 1990). In turn, it may thrive in seagrass meadows (Fischer et al 1987, Mercader 1991, Riera and Linde 2001, Castriota et al 2005b, Box et al 2009), particularly those dominated by the genera Cymodocea and Zostera (Brito et al 2002, Castriota et al 2005a, Espino et al 2011a, and less frequently in Posidonia beds (Beltrano et al 2006, Box et al 2010.…”