MEPS 374:215-227 (2009)  -  DOI: https://doi.org/10.3354/meps07741

ABSTRACT: We examined grey nurse shark Carcharias taurus utilisation of Wolf Rock (which is located within a marine sanctuary zone and is the most northern known aggregation site on the eastern Australian seaboard) between December 2002 and February 2008 using underwater censuses, photo-identification and acoustic tracking of individual sharks. Photo-identification surveys identified 181 individual C. taurus (161 mature females, 1 immature female and 19 mature males). Eighty-one of these were re-identified at least once at Wolf Rock (77 females and 4 males) between December 2002 and February 2008. A biennial reproductive cycle was indicated for 18 out of 28 females for which re-identifications spanned at least 2 mating and/or pregnancy events. Re-identifications of 9 out of 28 female sharks suggest that, on occasion, there may be 3 yr between pregnancy events. Male C. taurus were observed between July and January, but were absent between February and April. Fresh mating scars on female sharks were observed in late November and December and pregnancies were visible from late-February. Many pregnant sharks remained at Wolf Rock until August or September (9 to 10 mo post-mating) and demonstrated strong site attachment with 78 to 90% of their time spent within 500 m of the Wolf Rock aggregation site. C. taurus is listed as critically endangered along the east coast of Australia and there is concern about their population’s resilience globally. The improved knowledge of the reproductive periodicity of C. taurus and their behaviour during pregnancy will provide valuable information to assist with management throughout their distribution.

KEY WORDS: Aggregation · Site fidelity · Acoustic telemetry · Photo identification · Visual survey