Teagan Marzullo
PhD Candidate
Contact details:
+61 4 0252 8154

Room 456, D26 Building
UNSW, Kensington 2052

Member of the Fisheries & Marine Environmental Research Laboratory

Movements and estuary fidelity of stingrays.

Defining fish population dynamics, such as structure and connectivity, can elicit vital information required for effective conservational planning. Knowledge of both broad- and fine-scale habitat use, and how this is influenced by changing environmental parameters (i.e. fresh-water flow, temperature, turbidity, etc.), is also crucial for the development of successful conservational strategies (i.e. Simpfendorfer et al., 2010; Simpfendorfer et al., 2011). This information identifies valuable areas and/or environmental factors that may be key to a population’s recovery and can be used by governing authorities to ensure adequate assignment of protective boundaries, such as marine parks.

Research has consistently found that specific biological parameters are correlated with an increased risk of extinction in fish species (i.e. Myers and Worm, 2005). Species at the greatest risk typically possess K-selected life history traits, that is those who are long-lived, late to mature, large bodied and have low reproductive output. K-selected strategists are intrinsically susceptible to inadvertent human-induced population declines and extinction [i.e. Dasyatis fluviorum (Pierce and Bennett, 2010); Dulvy and Reynolds, 2002]. Lack of basic information regarding habitat preferences, movements, abundance and biology of these high risk species may hinder their management, particularly in distorted dynamic environments, such as estuaries. Stingrays are notorious K-selected strategists, and are overlooked due to their low marketable value, despite forming a significant proportion of by-catch in commercial fisheries.

Little is known about stingrays which inhabit shallow, coastal habitats, such as estuaries and embayments (e.g. Ballantyne and Robinson, 2010). Estuarine stingrays are of interest due to their potential top-down regulation by predators such as sharks (Baum and Worm, 2009; Ferretti et al., 2010; Myers et al., 2007), and potential trophic overlap with commercially important, benthic fish (e.g. dusky flathead Platycephalus fuscus). Ray populations may be strongly influenced by harvest of their predators (Myers et al., 2007), or by marine park sanctuary zones, but the implications regarding their trophic niche and movements can only be surmised. The conservation and management of coastal and estuarine species depends on understanding their residency and movements in relation to habitat and hydrography in these dynamic and anthropogenically altered environments.


Supervisor -

Professor Iain Suthers

Co-Supervisors -

Dr Nick Payne

Dr Matthew Taylor (NSW-DPI)

Dr Nathan Knott (NSW-MPA)



Marzullo, T. A., Wueringer, B. E., Squire, L., and Collin, S. P. Description of the mechanoreceptive lateral line and electroreceptive ampullary system in the freshwater whipray, Himantura dalyensis. Marine and Freshwater Research, 2011, 62: 771-779.