Antarctic marine hotspots identified by animal tracking

Satellite tracking of seal and seabird species in the East Antarctic sector of the Southern Ocean has identified six areas of marine habitat important to multiple species.

The research, published in Ecography in July, demonstrates a way of identifying marine areas likely to be of ecological significance, which can be used for conservation planning and management activities, ecosystem modelling, and to assess future changes in habitat use.

Computational ecologist Dr Ben Raymond, from the Australian Antarctic Division, said most satellite tracking (‘telemetry’) studies have been conducted on individual species and few have been able to consider multiple species at once.

‘Combining telemetry data from a diverse suite of Antarctic marine predators has allowed us to identify several marine regions and features important to these animals,’ Dr Raymond said.

‘These include regions accessible to breeding colonies, and winter polynyas — areas of open water that are often associated with increased prey availability.’

The study used two decades of telemetry data collected by Australian and French Antarctic research teams for Adélie and emperor penguins, light-mantled albatrosses, Antarctic fur seals, southern elephant seals and Weddell seals.

The preferred habitat of each species was identified by applying statistical modelling methods to the observed tracks. Each species model was then used to predict the habitat preference for that species over the entire region of interest.

When the team combined the results from the individual species, they found a high degree of overlap in six regions. The favoured regions were generally close to Antarctic and subantarctic breeding colonies, and winter polynya areas that are known to be highly productive and which provide diving predators with access to under-ice prey (see video animation below).

‘Areas of overlap were all located in the southern part of the study region, generally over the Antarctic shelf and waters immediately to its north, excluding deep, open oceanic areas,’ Dr Raymond said.

The results were consistent with previous studies which have shown, for example, that both Adélie and emperor penguins prefer habitat close to their breeding colonies during the chick-rearing period. Light-mantled albatrosses prefer offshore areas, closer to their subantarctic breeding islands.  Male and female southern elephant seals, in contrast, disperse widely from their colonies after breeding and concentrate on shallow parts of the continental shelf and areas of winter polynyas.

The study authors said their research, and similar research programs tracking multiple species, were important for Southern Ocean conservation planning efforts. This includes the establishment of marine protected areas currently being considered by the Commission for the Conservation of Antarctic Marine Living Resources.

Wendy Pyper
Corporate Communications, Australian Antarctic Division