Juvenile white sharks Carcharodon carcharias use estuarine environments in south-eastern Australia
Estuarine environments are known to provide important feeding, breeding, resting and nursery areas for a range of shark species, including some which are considered dangerous to humans. Juvenile white sharks (<3 m) are known to frequent inshore environments, particularly ocean beaches, but their presence in and use of estuaries and coastal embayments is unclear. Given that estuarine environments are often surrounded by highly populated areas, understanding how white sharks use these environments will not only assist with their conservation management, but also inform public safety policies. The use of estuarine environments by acoustic-tagged white sharks was investigated from 2009 to 2015 at Port Stephens, New South Wales and Corner Inlet, Victoria, both of which adjoin known nursery areas for the species. Juvenile white sharks were detected within both estuaries, with 20 individuals recorded within the Port Stephens estuary, including four on one day. Only one tagged shark was detected within Corner Inlet; however, monitoring effort and local tagging in the area was more restricted. Detections in Port Stephens were predominantly from October to January and peaked in November. This study demonstrates that the footprint of known nursery areas for white sharks in eastern Australia should be expanded to include their adjacent estuarine environments. Consequently, there is clear potential for them to be exposed to a range of anthropogenic estuarine impacts, and that human interactions are more likely over warmer periods (summer), when human use of such waterways is more prevalent.
KeywordsCarcharodon carcharias Corner Inlet Estuary Marine Port Stephens Threatened species Nursery area
Thanks to other staff and colleagues that contributed to this project (Roger Laird, Brett Louden, Peter Gibson), Kent Stannard (Tag for Life Foundation) and to Dr Joel Williams and Dr Hamish Malcolm for initial comments on the manuscript. Additional acoustic tag detection data were sourced from the Integrated Marine Observing System (IMOS)—IMOS is supported by the Australian Government through the National Collaborative Research Infrastructure Strategy and the Super Science Initiative.
Compliance with ethical standards
This work is an output of Project A3—A national assessment of the status of white sharks of the Marine Biodiversity Research Hub, funded through the National Environmental Science Program (NESP) and administered through the Australian Government’s Department of the Environment and Energy.
Conflict of interest
The authors declare that they have no conflict of interest.
This research was carried out under approval of the New South Wales Animal Care and Ethics Committee (permit ACEC REF 12/07-CSIRO) and the Tasmanian Department of Primary Industries, Parks, Water and Environment Animal Ethics Committee (AEC 1/2013–14).
- BOM (2015a) Summary Statistics for Corner Inlet (Yanakie), site number: 085301. Bureau of Meteorology. http://www.bom.gov.au/climate/dwo/IDCJDW3103.latest.shtml. Accessed 05 Jan 2015
- BOM (2015b) Summary Statistics for Nelson Bay (Nelson Head), site number: 061054. Bureau of Meteorology. http://www.bom.gov.au/climate/averages/tables/cw_061054.shtml. Accessed 05 Jan 2015
- Branstetter S (1990) Early life-history implications of selected carcharinoid and lamnoid sharks of the northwest Atlantic. In: Pratt Jr HL, Gruber S, Taniuchi T (eds) Elasmobranchs as living resources: advances in the biology, ecology, systematics, and the status of the fisheries. Proceedings of the 2nd United States–Japan workshop NOAA Technical Reports NMFS, vol 90. pp 17–28Google Scholar
- Bruce B, Bradford R, Hughes B, Gallen C, Harasti D, Carraro R, Gladstone W (2013) Acoustic tracking and aerial surveys of juvenile white sharks in the Hunter-Central Rivers Catchment Management Authority region. Final Report. CSIRO, HobartGoogle Scholar
- Castro JI (1993) The shark nursery of Bulls Bay, South Carolina, with a review of the shark nurseries of the southeastern coast of the United States. In: The reproduction and development of sharks, skates, rays and ratfishes. Springer, pp 37–48Google Scholar
- Chapple TK, Jorgensen SJ, Anderson SD, Kanive PE, Klimley AP, Botsford LW, Block BA (2011) A first estimate of white shark, Carcharodon carcharias, abundance off Central California. Biol Lett rsbl20110124Google Scholar
- Flater D (2014) XTide. http://www.flaterco.com/xtide/. Accessed 07 Oct 2015
- Francis M (1996) Observations on a pregnant white shark with a review of reproductive biology Great white sharks: the biology of. Carcharodon Carcharias 157:172Google Scholar
- Grubbs RD, Musick JA, Conrath CL, Romine JG (2007) Long-term movements, migration, and temporal delineation of a summer nursery for juvenile sandbar sharks in the Chesapeake Bay region. Am Fish Soc Symp 50:63–86Google Scholar
- Heupel MR (2007) Exiting Terra Ceia Bay: examination of cues stimulating migration from a summer nursery area. In: McCandless CT, Kohler NE, Pratt HL Jr (eds) Shark Nursery Grounds of the Gulf of Mexico and the East Coast Waters of the United States. American Fisheries Society, Bethesda, pp 265–280Google Scholar
- IUCN (2016) IUCN Redlist of Threatened Species. http://www.iucnredlist.org. Accessed 09 Oct 2016
- Molloy R, Chidgey S, Webster I, Hancock G, Fox D (2005) Corner inlet environmental audit. Report to the Gippsland Coastal Board. CSIRO, HobartGoogle Scholar
- Nel DC, Peschak TP (2006) Finding a balance: White shark conservation and recreational safety in the inshore waters of Cape Town, South Africa. In: Proceedings of a specialist workshop. WWF South Africa Report Series—2006/Marine/001 Annexure vol. 1Google Scholar
- Santana-Morales O, Sosa-Nishizaki O, Escobedo-Olvera MA, Oñate-González EC, O’Sullivan JB, Cartamil D (2012) Incidental catch and ecological observations of juvenile white sharks, Carcharodon carcharias, in western Baja California, Mexico. In: Domeier ML (ed) Global perspectives on the biology and life history of the white shark. CRC Press, Boca Raton. doi: 10.1201/b11532-18 Google Scholar
- SMH (2014) Great white shark filmed swimming in Lake Macquarie. Sydney. http://www.smh.com.au/environment/conservation/great-white-shark-filmed-swimming-in-lake-macquarie-20141205-120yyj.html Accessed 24 Oct 2016
- SMH (2015) Shark video shows Lake Macquarie great white taking flight. Sydney. Available at: http://www.smh.com.au/environment/animals/shark-video-shows-lake-macquarie-great-white-taking-flight-20150916-gjogh8.html Accessed 24 Oct 2016
- Team RC (2009) R: a language and environment for statistical computing. R Foundation for Statistical Computing, ViennaGoogle Scholar
- van Lier J, Harasti D, Laird R, Noble MM, Fulton CJ (2017) Importance of soft canopy structure for labrid fish communities in estuarine mesohabitats. Mar Biol. doi: 10.1007/s00227-017-3068-2
- Victoria P (2015) Corner Inlet Marine National Park. http://parkweb.vic.gov.au/explore/parks/corner-inlet-marine-national-park/environment. Accessed 20 Oct 2015
- Vila-Concejo A, Short A, Hughes M, Ranasinghe R (2007) Flood-tide delta morphodynamics and management implications, Port Stephens, Australia. J Coast Res 50:705–709Google Scholar
- Wood SN (2006) Generalized additive models: an introduction with R. CRC Press, Boca RatonGoogle Scholar
- Zeileis A, Kleiber C, Jackman S (2008) Regression Models for Count Data in R. Journal of Statistical Software 27:1–25Google Scholar