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

Evidence for rapid recovery of shark populations within a coral reef marine protected area

“…This suggests that Cartier Reef could have only provided a very limited source of immigrant sharks for recovering populations at Ashmore. Additionally, tracking studies at isolated reefs both in the same region (Rowley Shoals) and elsewhere in tropical Australia have shown that C. amblyrhynchos adults tend to be resident over protracted time frames (months -years) (Barnett et al 2012;Espinoza et al 2015;Field et al 2011). This is confirmed by a recent genetic study that has shown that populations of C. amblyrhynchos on the Rowley Shoals and the Scott Reefs are likely to be largely self-recruiting and demographically independent (Momigliano et al 2017).…”

“…However, our sampling at Ashmore was not spatially restricted and we found high abundances of reef sharks throughout a wide range of available habitats, suggesting that they did not occur in response to localised prey abundance. Although we sampled in the spring of 2004 and summer of 2016 at Ashmore, this is unlikely to have had an effect on MaxN (or additional metrics - Figure A.6), as there is little evidence to support the suggestion that differences in reef attendance of C. amblyrhynchos at isolated reefs (Barnett et al 2012;Field et al 2011) can be explained by seasonal or environmental drivers (Espinoza et al 2015;.…”

Trophodynamics as a Tool for Understanding Coral Reef Ecosystems

“…Telemetry can also be used to supplement other methods to identify behavioral adaptions to resources such as targeting invasive species (Bierwagen et al, 2017). Improved analytical methods for ecology such as network analysis (Espinoza et al, 2015), Bayesian statistics (Johnson et al, 2010) and statespace models (Jonsen et al, 2005) are assisting predictive capability of movement relative to environmental variability. For example, telemetry has helped define population dynamics through focused mark-recapture models (Dudgeon et al, 2015).…”

“…Relationships within a community, energy flow, and linkages between biota and the environment are all encompassed in Lindeman's approach. The idea of energy flow in an ecosystem strengthened earlier studies such as biomass pyramids (Elton, 1927;Turney and Buddle, 2016), opening the way for incorporation of food webs into ecology to understand ecosystem processes (McIntosh, 1986;Sale, 2002). Definition of ecosystem processes is crucial to trophodynamic studies because they encompass biological, physical, and chemical mechanisms that link species and facilitate energy flow.…”

Conserving coral reef organisms that lack larval dispersal: are networks of Marine Protected Areas good enough?

“…For example, reefs that are very close are likely perceived as continuous habitats; in these conditions reef sharks may move continuously between neighboring reefs crossing the boundaries of different management zones (Heupel et al, 2010). As distance between reefs increases, gray reef sharks exhibit higher site fidelity, but a large proportion of them still hop from reef to reef, moving to (or through) unprotected areas (Espinoza et al, 2015). This may be a problem if most reefs in a network of MPAs are small and geographically very close to each other.…”