During this time I began my observations of the short-tail stingrays using Currambene Creek. The idea was the send the first 5 days tagging the rays with visual tags to help us ID each of them, the next two weeks making baseline observations of their site use and then the next two weeks conducting simulated provisioning where we add fish scraps into sites where the rays aren't typically seen foraging to see how easily they are swayed by a food reward.
One thing I quickly realised was that fieldwork almost never goes to plan. We ended up extending tagging, reducing observation times and adding a whole new aspect to the project - social network analysis.
Our observations from August (late winter) led us to question the seasonality of the movements of the stingrays in and out of Currambene Creek and we decided that another field trip in summer would be needed. The plan was to head into the field for two weeks and repeat the baseline observations and social network observations at the site and compare this to the observations taken in August.
... that was the plan.
Then there was day 2... and 3... and 4... with no stingrays. Something strange was happening. The tides were getting better, there was a tonne of fish cleaning. But the scraps were still there the next day which was unheard of at this site - the rays always cleaned up. The locals agreed with us that it was highly unusual for there to be none. If I had a dollar for every time I was told "But they're always here", I could have paid off the entire fieldtrip myself! Of course their abundance fluctuates; however, our observations in August indicated we should have seen as least 1 cruising by within those first 4 days... After all we had 15 individuals using the site back in August and we expected more in summer.
As this species is a marine stingray and is using a creek it would make sense that high freshwater influx could result in the exclusion of the species; however, you would expect that the level of freshwater entering the creek would have to be incredibly high. The site is also near the mouth of the creek and at the time it was nearing a full moon resulting in high hightides, so the creek should have been flushed with salty water twice daily with the tides. Observations from August suggested that even during times of rain and the following days, we were seeing at least 1 or 2 rays most days. So in my personal opinion, freshwater influx didn't seem to explain the situation fully.
It is believed that this species of ray breeds in summer, so it may have been that they had headed into the bay to breed. Although the reality was we would have no idea if this was the case.
By day 5 we had still not seen any rays and the decision was made to cancel the rest of the trip. Whilst what was happening was super interesting, we didn't have the time or equipment to assess the situation fully, so we cut our losses, packed the car and headed home with out tails between our legs.
Then yesterday I received a phone call.
It was my co-supervisor, Dr. Nathan Knott. He had stopped by the site after work to have a look-see for any rays assuming he would not see any. And of course he sighted 3 rays, believed to be Stumpy, Big Momma, and Raylene who were identified back in August.
That's right... The VERY NEXT DAY after we left the field, 3 of the rays returned to the area like nothing had happened.
So I guess the moral of the story is - fieldwork never goes to plan.
"The things that make you happy are just as much a test as the things that make you sad."