This time last year, we held the Great Goolwa Cockle Challenge to raise awareness of the importance of sustainable management of recreational fisheries. Prior to the event we tagged and released over 3000 cockles (also known as pipis) at Goolwa Beach. On the community day, Saturday 13th of January, 2018, we challenged the 450 attendees to recapture as many tagged cockles as they could. In total, 160 tagged cockles were re-found on the community day. Since that time, community members have reported an additional 60 tagged cockles. So, approximately 6.5% of all tagged cockles have been recaptured, which is pretty good for any animal tagging study.
Not surprisingly, most recaptured cockles were found in the weeks and months after the community event, but we have had nine cockles found after being at large for over 300 days, with one cockle (0327) at large for a whooping 447 days before being recaptured this week! A further two cockles were recaptured 406 and 409 days after tagging!
Although not the primarily objective, we have been able to obtain some information on growth and movement from these recaptured cockles. The individuals which were at large for 406 (tagged at 34 mm) and 409 days (tagged at 35 mm) grew 6 and 9 mm, respectively. Remarkably, the cockle at large for 409 days was recaptured 1.2 km from where it was tagged, although most recaptured cockles didn’t move much, being found in the vicinity of where they tagged. This is all interesting information that is adding to our understanding of the species.
With the warm weather forecast for this week and the end of school holidays approaching, now is the perfect time to head to the beach. Please report any tagged cockles to NGT’s Sylvia Zukowski on 0438 815 489 or by email ().
In addition to the this, we are conducting fisheries-independent population monitoring at three periods (before, during, after) the recreational harvest season (1 November to 30 May). For more information on management of the recreational fishery please visit www.pir.sa.gov.au/fishing/fishing_limits/pipis.