Great Hammerhead Shark (Sphyrna mokarran)

Mohamed bin Zayed Species project number 0925307

The great hammerhead shark, Sphyrna mokarran, is the only hammerhead species to be listed as Endangered by the IUCN Redlist. In Australian waters, the life history and catch content of S.mokkaran is defined as Data Deficient, and the species is in urgent need of assessment (IUCN Redlist). If current rates of decline seen elsewhere in its range (e.g. Mediterranean Sea (Ferretti et al. 2007)) are occurring in Australia, then fishing and management practices need to change to ensure the long term conservation of this species. At present there is very little known about the movement patterns and biology of S.mokarran in Australian waters. As such, research is needed to provide both an insight into the current conservation status of this animal and to implement the correct management strategy to protect this charasmatic species. This project aims to fulfill these gaps, with the overall mission objective being to provide substantial new information about movements and behaviours of this shark along the Australian east coast. We will use satellite tags to monitor S.mokarran off the east coast of Australia, in the first major investigation into the movement patterns of this species anywhere in the world. In addition, we will link these movement results to ongoing investigations into the biology of this species. We will utilise state of the art satellite tags to ascertain the movement patterns and depth and temperature preferences of these animals. As this integrated approach has not been undertaken on this species, it is anticipated that the project will act as a case study to highlight future worldwide research and conservation directions for S.mokarran. Grass-roots satellite tracking investigations on large sharks, provide valuable information to species management and long term conservation efforts (Brunnschweiler and Van Buskirk, 2006). Information that can be collected includes localised site fidelity, the interconnectivity of populations, recruitment into adult populations and migrations to feeding and mating grounds (Bruce et al. 2006, Heithaus et al. 2007, Rowat et al. 2007). It is not currently known whether S. mokarran within Australian waters form one large population or if there are numerous sub-populations inhabiting separate and distinct habitats. This project will shed light on this key issue. By understanding the interconnectivity of S.mokarran populations it will be possible to critically evaluate a key life history component for this species and thus assist in development of management approaches to ensure over-exploitation does not occur. The focus of this research, that began in early 2009, will occur in three inshore coastal embayments along the Queensland coast. These areas are Cleveland Bay, Hervey Bay and Moreton Bay. These sites have been chosen as they represent areas that S.mokarran has been known to frequent, as well as being areas that have long standing commercial shark fisheries. Therefore, a key objective of this study will be provide various stakeholders (e.g. fisheries managers) within these three areas, with new recommendations (e.g. site specific management) to improve the conservation status of this species. As such, outcomes are expected to have direct application in future research and management approaches for this species locally and globally.