Listen: Click here to hear Duncan Leadbitter's radio interview with Lindsay McDougall from ABC Illawarra.
Last year I wrote four articles about the shark notifications sent by our detection station located about 900m (distance measured by drone) off Stanwell Park beach. I also did a radio interview with Lindsay McDougall from ABC Illawarra.
I have now analysed the data for the 23/24 ‘season’ and will do a couple of articles comparing the two years and also reveal the much awaited ‘frequent visitor’ awards. This year there will be a new category, for the individual shark(s) that have turned up both years.
The sampling year covers June to May. The total number of detections (see September 2023 edition for how this is determined) was higher in 2023/24 compared to 22/23 at 65 versus 53 due to more detections of great whites. These showed a very noticeable increase in detections during the winter period (see chart). Great whites dominate the shark numbers caught by the drumlines being about 62% of captures for the 21/22 and 22/23 sampling periods.
The reasons for this could be many. There are likely more tagged sharks about and if we look at when the sharks were first tagged, the vast majority (14 out of 18 individual sharks detected) have only been tagged for a year or less. It could also be that there are more whales or fish around. There may be more great whites in general. Who knows. It’s also interesting that the drumlines in the Illawarra did not catch any target sharks during 22/23 so all of our visitors have been caught elsewhere.
For the bull sharks, the number of detections was the same as last year and, as was the case last year, they turn up in the late summer and autumn when the water is warmest (see chart below). Unlike the great whites, most bull sharks (8 out of 11 detected) have been tagged for 5 years or more. There could be a variety of reasons for this related to the relatively low numbers tagged (compared to great whites and tigers), age of animals tagged (which influences habitat preferences), interannual factors like currents, food availability and more.
As I said last year, this is a very small dataset both in terms of numbers of listening stations I check and years of data so it pays not to get too focused on trying to interpret things at this stage.
