Case studies: New fields of research

A wider range of applications

The G5 is much smaller and lighter than previous generations of Data Storage Tag (DST), yet has a much higher memory. The tag is opening up new fields of research for a wider range of species.

Picking up penguin behaviour

One of the first applications for the tags was studying Little Penguin behaviour in Australia.

Scientists studying Little Penguins on Phillip Island used G5 tags to collect their data. Large tags have the effect of introducing underwater drag, which can affect the behaviour of tagged diving birds. As the drag effect is cumulative so the behavioural effects may be increased over time, and accuracy of results diminished. The small size of the G5 means reduced drag and therefore genuine data is collected.

Tags were attached to penguins by adopting a system previously used successfully on several other seabird species. Data was collected during the day-long diving trips that the penguins undertook.

Depth and temperature information was recorded every second during the penguins’ dives, before downloading and producing graphs of the results once the tags were retrieved.

Right plaice, right time

In the past, studies of plaice tagged in the North Sea have mainly been restricted to tagging mature female fish. This means there are significant gaps in our knowledge of plaice populations and behaviour. A better understanding will play an important role in safeguarding the future of the stock.

Female plaice are larger than the male, and this has allowed them to carry previous generations of DST. The small size and low weight of the G5 enable it to be used successfully to tag male (and immature female) plaice.

Male plaice tagged with G5’s have already revealed new observations. Population structures are already being seen that have not been predicted in spite of 100 years of conventional tagging data. For the first time the migration of a male plaice from the southern North Sea to the western English Channel (a movement of over 500 km during nearly 200 days) has been captured by an electronic tag.

The previous studies have demonstrated that North Sea plaice have a relatively elaborate population structure, and also that the behaviour of male and juvenile fish differs from that of adult females. However, understanding of the relationship between spawning areas, nursery grounds and adult areas is limited. The G5 will provide more information and better insights into the lives of the North Sea plaice.