Spatial and temporal movement patterns of a multi-species coastal reef shark aggregation

Abstract

The quantification of spatial and temporal movement patterns of coral reef sharks is important to understand their role in reef communities and to aid the design of conservation strategies for this predatory guild. We observed 4 species of reef sharks aggregating in an inshore bay in the north of Western Australia for over 2 yr, using acoustic telemetry and visual censuses to examine how they partitioned this site in space and time. We fitted 58 sharks with acoustic transmitters: Carcharhinus melanopterus (36), C. amblyrhynchos (11), Negaprion acutidens (7) and Triaenodon obesus (4). Aggregations consisted primarily of C. melanopterus, although C. amblyrhynchos and N. acu tidens were often present. We observed aggregations by visual census in summer (maximum of 44 sharks). Detections were highest during warmer months (Sep to Mar) for all species, although some individuals showed year-round residency. C. melanopterus, C. amblyrhynchos and N. acutidens had strong diel patterns of attendance at the aggregation site. Peak daily detections occurred from 13:00 to 14:00 h local time for C. melanopterus and C. amblyrhynchos; juvenile C. melanopterus and N. acutidens peaked at 05:00 and 10:00 h, respectively. There was considerable spatial overlap of core areas of use (50% kernel density estimates) at the northern end of the bay by all species; the southern end was used primarily by C. melanopterus and N. acutidens. Aggregations of C. mela nop terus and C. amblyrhynchos consisted mainly of adult females, some of them pregnant. Courtship behaviour in C. melanopterus and T. obesus suggests that these aggregations are related to reproduction. All species displayed inter-annual site fidelity. The long-term presence of juvenile C. melanopterus and N. acutidens also suggests that this bay provides suitable conditions for younger age classes.

Diversity, abundance, and distribution of reef sharks on outer-shelf reefs of the Great Barrier Reef, Australia

“…Hobson 1963;Randall 1977;McKibben and Nelson 1986;Robbins et al 2006;Papastamatiou et al 2009b) as well as general movement patterns (e.g. Heupel et al 2010;Speed et al 2010Speed et al , 2011Barnett et al 2012;Vianna et was not observed on reef flats, and density estimates for this species were higher on the reef slope compared to the back reef. This result is comparable with previous research, which observed C. amblyrhynchos in greater numbers on outer reef slopes that are associated with strong currents (McKibben and Nelson 1986;Wetherbee et al 1997;Papastamatiou et al 2006;Field et al 2011).…”

Residency patterns and movements of grey reef sharks (Carcharhinus amblyrhynchos) in semi-isolated coral reef habitats

“…Long-term movement and residency patterns of reef sharks can also provide insight into the reproductive behaviour of a species. For example, movement information can be used to identify shark aggregations (Economakis and Lobel 1998;Speed et al 2011), size/sex segregation patterns (Knip et al 2012a;Chin et al 2013a, b), and potential mating and parturition behaviours (Papastamatiou et al 2013;Werry et al 2014), which ultimately have an important conservation value for a species. The present study examined the longterm residency patterns and space use of grey reef sharks C. amblyrhynchos in the central GBR.…”

Uso de hábitat de Triaenodon obesus (Carcharhiniformes: Carcharhinidae), Rhincodon typus (Orectolobiformes: Rhincodontidae) y Manta birostris (Myliobatiformes: Myliobatidae) en el Parque Nacional Natural Gorgona, Pacífico colombiano

“…Diferentes autores han planteado alta fidelidad del aletiblanco a los lugares de asentamiento y agregación (Musick, Harbin & Compagno, 2004;Speed et al, 2011;Whitney et al, 2012). En particular, Speed et al (2011) sugieren que esta fidelidad se presenta a través del tiempo, e incluso en grandes sistemas arrecifales continuos, proponiendo que ello se debe principalmente a eventos reproductivos, más que a facilidades de alimento o protección contra depredadores.…”

“…En particular, Speed et al (2011) sugieren que esta fidelidad se presenta a través del tiempo, e incluso en grandes sistemas arrecifales continuos, proponiendo que ello se debe principalmente a eventos reproductivos, más que a facilidades de alimento o protección contra depredadores. Así mismo, Whitney et al (2012) registraron alta filopatría de la especie con múltiples recapturas fotográficas de un mismo ejemplar en un mismo sitio hasta por siete años, y documentando mayor filopatría en las hembras que en los machos.…”

“…La mayoría de estos estudios se han realizado en áreas geográficas como Australia (Meekan et al, 2006;Holmberg et al, 2009;Huveneers et al, 2009;Speed et al, 2011), indonesia y Tailandia (Theberge & Dearden, 2006;Stacey, Karam, Dwayer, Speed & Meekan, 2008), el Mediterráneo (Canese et al, 2011), el Mar Rojo (Hussey et al, 2013), el Atlántico y el Caribe (Luiz et al, 2009;Cárde-nas-Palomo, Herrera-Silveira & Reyes, 2010;de la Parra-Venegas et al, 2011). Por su parte, en el Pacífico Oriental dichos trabajos se han iniciado recientemente y las publicaciones disponibles se restringen a poblaciones de Manta alfredi y M. birostris en Hawaii (Clark, 2010;Deakos, Bajer & Bedjer, 2011) y Sphyrna lewini en la isla Malpelo (Bessudo et al, 2011).…”