GREEN TURTLES and GUIDED FISHING OPERATORS

Hi again for another week.

The Garngi Rangers have had a busy week with quite a few hours on the water. For two days we worked with the Northern Territory Government National Park rangers from the Coburg Peninsula and some scientists. The name of the park is Garig Gunak Barlu. 'Garig' is the language that was once spoken there however sadly there are now no surviving speakers. 'Gunak' means country - both land and sea. And 'Barlu' means wide open blue waters.

Some scientist from the Charles Darwin Uni (CDU) are seeking to gain a better understanding of marine animals like turtlers, dugong, manta rays, dolphins and false killers whales - that really are a type of dolphin.

We met them near Croker Island and headed out to Grant Island to the east of Croker Island, where there are lots of turtles. Below is their vessel - 'Meander 2'. 

Before we were able to start our turtle survey work we had to do some 'compliance work'. As we approached Grant Island we noticed a couple of smaller fishing vessels, so had to detour to check out what they were up to. This time of the year we get quite a few guided fishing operators in this area. People pay considerable money to come up from down south and do some good fishing. Sadly, not all respect the fishing regulations or the traditional owners. As we had to remind one 'cheeky' fisherman, if these indigenous people entered someone's property down south without permission and setup camp or started fishing, they would most likely end up in court. 

We spoke to the occupants on the vessel below who advised that the 'mother vessel' (and skipper) were anchored around the other side of the island.

On the way to the mother vessel we observed a second fishing tender.

We came along side the mother vessel and spoke with the skipper. Some of the information he provided about his operation did not 'stack up'. Our report will be sent to the NT Fisheries and Water Police to followup and take appropriate action. 

After that little 'detour', it was back to the turtle survey. 

The scientists were wanting to catch marine turtles, record their size, gender and location and also take a small piece of skin from a flipper for DNA analysis. So, how do you catch a turtle? The locals mostly use a harpoon however that would not comply with the standards required of scientific research. So we had to firstly go to an area of 1-2 meters of water where turtles graze and when a turtle is spotted follow them and get close enough for a diver to dive in and catch them - by hand. Sounds easy enough - not so! When turtles are fresh, they can put on an amazing burst of speed.

The short video below shows the latter part of this catching process. It must be remembered that turtles are heavy solid animals and have powerful jaws and flippers. They can bite, and if they do hit the diver with a flipper it can hurt - a lot.

They are then brought to the side of the vessel and lifted in. For the larger turtles, this is no small task. This turtle below is a female Green Turtle, very common is this area. Once in the vessel a whole bunch of information is recorded.....

Including size......

And then a small piece is cut out of one of the rear flippers for DNA purposes.

A wet cloth is placed over the turtles head while this is done and then it is returned to the water ASAP. Some of the male Green Turtles had trackers fitted - but at $4000 per tracker, the supply was limited. 

The scientists are concerned about the marine turtle population. When female turtles come ashore to lay their eggs, they dig a hole in the beach above the high water mark. The temperature of the nest determines the gender of the young turtles - the hotter the nest, the more females. Ideally the nest should be around 29 degrees. On the Great Barrier Reef coast scientists have observed some nests producing 99% females. Even more concerning, last week the Garig Gunak Barlu rangers found a nest where the temperature was 35 degrees and with 1/3 of the eggs 'cooked' - they had been successfully fertilised however died before hatching. 

In the next blog I will do part 2 - more turtle work and also some dolphins work as well. How would you collect DNA sample from a dolphin as they are so fast and agile - and without causing them distress? 

Cheers until next time.

Bryan Nancy and PK