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The reintroduction of traditional harvesting at Arrawarra Headland came about as a direct result of discussions between Garby Elders and the managers of the Solitary Islands Marine Park. This process included the development of a Conservation Plan for the headland that provided a guideline for harvesting and associated activities. One of the stipulations of the plan was that harvesting activities should be monitored: this provided a great opportunity for collaborative work between Garby Elders, marine scientists and marine managers.

The Approach

To be successful and relevant, it was important that the monitoring programme was carefully planned. From the outset, it was clear that it was not going to be possible to monitor all species that were to be harvested. The approach we took was therefore to:

  1. identify the main species to be harvested;   
  2. determine the best methods to measure harvesting impact on the species with the highest harvesting pressure;
  3. provide traditional users with training in scientific monitoring methods; and
  4. collect long-term data on the effects of harvesting on target populations.

Which Species?

Based on historical records from a nearby midden, and from field excursions with Garby Elders, two species of large molluscs (shells), Turbo militaris Reeve, 1848 and Turbo torquatus Gmelin 1791 (known as gugumbal), were identified as the primary targets for harvesting. T. militaris is much more common than other species of turban shell in this region. We therefore designed the monitoring program to focus mainly on this species.

Study Design

Turbo militaris occurs at the lowest tidal levels where it can be found (during the day) in crevices, and under overhangs and large aggregations of the tube-worm Idanthyrsus pennatus. Pilot studies found that the most cost-effective sample unit size was a 4-m2 quadrat, and that 9 replicates should be evaluated at each site.

To measure the effect of harvesting, we surveyed 4 sites before harvesting recommenced at Arrawarra Headland, and regularly thereafter. Arrawarra Headland was the experimental site; the other 3 sites (Flat Top Point, Diggers Camp and Mullaway Headland) were similar in all features except that gugumbal harvesting seldom, if ever, occurs (2 are 'no take' zones in the Solitary Islands Marine Park).

Because collectors often choose animals of a certain size (usually the bigger ones, as they provide more food), we also measured all of the gugumbal in our quadrats to see if the average size changed over time.

Field Work and Training

While field work can be a lot of fun, it is also one of the most important activities of the project. The research team, composed of scientists, managers and Garby Elders, all share the various jobs. Before data collection started, 2 training workshops were held during which all aspects of the project were taught and practised. The jobs include: finding the gugumbal in each quadrat (which includes feeling around under rocks to find hidden ones – we use gloves for this!); measuring the size of each shell; and recording all of the information on data sheets. The data sheets are printed on waterproof paper as, working at the bottom of the shore, the study team often gets quite wet.

What Have We Found?

So far, we have found that the number of gugumbal is quite variable not only between headlands, but also within a single headland over time. There has been no obvious decline in gugumbal at Arrawarra Headland but this is mainly because harvesting rates have been much lower than originally anticipated. For this reason, we have included another headland in the study from which we experimentally remove gugumbal twice per year. Harvesting is carried out by Garby Elders to make sure the experiment is realistic. At this stage, it is too early to determine if harvesting has affected gugumbal numbers and sizes at this site. Some of this information is summarised in a poster that was presented at a national conference in 2006.

Ongoing Research

We now have a lot of information about gugumbal and are using this to support other projects. For example, we have been able to look at the size of the opercula (the stony trapdoors that seal the shell) in local middens, and work out which-sized animals were most commonly harvested 1000 years ago. By comparing this size-range to that of living animals at Arrawarra Headland, we can determine whether or not sampling was selective.

Gumbaynggir Nation
Arrawarra Headland
Fish Traps
Traditional Fishing
Other Food from the Sea
Hunting and Cooking
Arrawarra Midden
Bush Calendar
Useful Plants Trees
Useful Plants Fruit
Useful Plants Leaves
Scientific Monitoring
Gumbaynggirr Language
Gatherings and Ceremonies
Oral Histories