Bulletin 41 - July 1990: How Not to go Turtle Hunting

How Not to go Turtle Hunting

After enjoying erudite articles in the ENHG Bulletin for a number of years, written by people whom I imagine could provide the Latin names for any specimen at 100 meters, I feel sure that there must be many readers who, like myself, want to record their experiences in print but who feel under qualified to do so. I hope I might encourage such faint hearts by putting pen to paper to relate how, given an excellent opportunity to make useful scientific observation, I was able to snatch defeat from the jaws of victory and not even identify my subject.

Ever since my first visit to Qarnein Island in 1982, I have been fascinated by the evidence of the turtles nesting on the beaches and by the occasional brief sightings while swimming. The telltale signs of nesting activity are the parallel lines of scuff marks, resembling miniature tank tracks, leading from the water’s edge to a disturbed area, usually on the drift line and amidst a jumble of wood and other jetsam. The tracks often lead to a second disturbed area before heading off back down the beach again. The first nest I ever found got the better of my curiosity and I dug down with my hands to find a clutch of exactly 100 eggs, like soft-shelled ping pong balls, about 40 cm below the surface. I then recovered them with sand and attempted to obliterate all signs of the turtle’s presence, since the eggs are sought after avidly by visiting fishermen, who seem to know to the day when the first nesting turtle will come ashore (and for that matter when the first tern colony will lay). The cover up operation is exhausting and, quite frankly, usually pointless, as the local fishermen know exactly where to look and often probe likely areas with a thin rod to pinpoint the eggs.

However, despite many hours spent wandering the beach at all hours of the night, I have not until recently managed to observe a turtle actually in the process of nesting.

In the water, turtles are usually shy, but can be curious. My first sighting this year was a male, identified by the claw on the ‘wrist’ of the front flipper and short, pointed tail. It swam up to within a few feet of me before recognizing me as a dreaded human, at which he turned and ‘flew’ through the water at an astounding speed, being lost to sight within a few seconds.

A few days later, on 23^rd April 1989, I noticed a dark blob in the sea about 50 m offshore. Through the binoculars I realized it was a turtle head above the surface, and then was surprised to see that it had two heads. Intrigued, and throwing caution (and clothes – an advantage of living on an almost deserted island) to the winds, I swam out to where I had last seen it. The water was murky but over some massive coral heads I detected two turtles in obvious ‘flagrante delicto’. They were both large, and even allowing for the natural magnification of the water, the bigger female appeared to have a carapace length of over one meter. They were a strangely beautiful sight, the female swimming lazily along and the male grasping her tightly with front flippers.

They were dreamily oblivious to my presence until an incautious movement caused them to suddenly notice me, break apart and swim off in different directions. Nesting activity began in late April, and when I returned to Qarnein on 1^st May 1989 after a week’s absence, I counted more than 30 nesting depressions. Nesting continued regularly throughout May with a total of perhaps 100 for the month. A percentage of these were raised, and even two adult turtles caught by local fishermen on May 21^st, their ignominious fate to be towed back to Abu Dhabi behind the dhow so that they would arrive in prime condition for killing.

On Sunday 28^th May at 8:30 pm, just on high tide, I was optimistically searching the beach for turtles. Since I had spent three summers without finding one, I was not seriously expecting any results. I was therefore both surprised and delighted to see one at the top of the beach, digging beneath the cover of some scrub. I returned to our accommodation, less than 100 m away, to inform my associate and together we returned to await events. I had read that laying turtles are oblivious to disturbance, but this one, presumably bothered by our presence and the torchlight, abandoned operations. Looking up available information (mainly Mr. J.N.B. Brown’s article in Bulletin No. 34) I was disappointed that I was unable to positively identify the species from memory.

The following night (my last on Qarnein) I again made my way along the same stretch of beach. It was about 8 pm, just getting dark, and the tide just beginning to ebb. After traversing the 200 m stretch of beach without seeing any new tracks, I retraced my steps to find, virtually at my starting point, a fresh set of tracks crossing the virgin sand. Less than 10 minutes had elapsed, but the turtle was already digging, rather low down on the beach, just above tide line. I sat down quietly to watch without the aid of a torch, so as not to repeat the previous evening’s disappointment. I thought all was lost when she hauled herself out of the depression and started to move off. However, she simply walked about 4 m away and commenced digging again. Almost all the initial digging was accomplished with the front flippers, energetic sweeps sending the sand spurting two or three meters behind it. As I was by this stage lying only a mere meter to the rear, the effect was somewhat similar to stepping out into the teeth of a shamal.

Once a depression similar to the first one had been excavated (about 70 cm wide by 20 cm deep), the turtle hoisted itself up onto the sloping side so that its tail was to the rear of the center of the hole. A deeper central hole was then dug by outward movements of the rear flippers, accompanied by a slight sideways swaying of the rear end. At this stage all movement ceased for 10 minutes or so, presumably while the eggs were laid. Although my face was only half a meter from the hole I dared not use the torch so was unable to see clearly.

Approximately 40 minutes after digging operations had originally commenced, the turtle again began to move, this time filling in and tamping down the sand in the central hole with inward movements of the rear flippers.

After this, strong flicks of the front flippers sent sand flying over the back of the turtle, half burying it and the observer who had to beat a hasty retreat. Once the nesting area was covered to the turtle’s satisfaction – a prolonged operation lasting about half an hour – it turned around (the first time it had radically altered its position) and lumbered back down the beach. However, its problems were not quite at an end, as I decided to take it back to our accommodation to measure and weigh it. I carried the struggling and highly indignant chelonian back; a somewhat exhausting job as I was constantly belabored by its flippers, and when I finally collapsed with an armful of turtle onto the bathroom scales I found it weighed a healthy 31kg. The turtle was obviously unhappy with its sudden abduction and incarceration, so after quickly measuring the carapace, I again endeavored to identify it. Now, I am sure that to a Turtleophile the difference between a Ridley and a Hawksbill is the easiest distinction to make, but to an anxious amateur, concerned at his captive’s efforts to plough straight through the nearest wall, the task proved ridiculously difficult. Are the scutes imbricated? How many prefrontals are present? Do the infra-marginal scutes have pores? Yes, the plates do seem to overlap, though only slightly. It seems to have four prefrontal scales, but with most of the head covered with barnacles (some over 4cm in diameter), it is difficult to tell. And what in the world are inframarginal scutes anyway? Eventually I made a rapid sketch (later proving to be quite useless) and returned her ladyship to the beach. After a few seconds’ rest while the waves lapped over her, she heaved herself into the breakers and disappeared rapidly from view.

As an experience, something I wouldn’t have missed for anything. As a scientific exercise, it ranks with Icarus’s attempts at heavier-than-air flight; however, one interesting point arises; was it my disturbance that caused the turtle to move on to the second site? I don’t think so. I have noticed that the majority of nesting attempts consist of two depressions a meter or two apart, and I have always presumed that the original hole had been abandoned because an obstruction had been encountered, or conceivably because the moisture content or temperature of the hole was just not right. But in this case there were no obstructions and the turtle had not yet dug the egg cavity, so the soil condition does not seem to have been a factor. The second hole was at the same height along the beach and, in fact, identical factors applied at both adjacent sites. Perhaps there is some survival value in digging an obvious and unused nest before depositing the eggs in a more carefully concealed position.

The turtle was identified very tentatively as a Green Turtle. The carapace measurements were 67 cm long by 62 cm wide, taken along the curve of the shell.

(See Bulletin No. 34, pp 22-25 – Identification Key for the World’s Sea Turtles, by J.N.B. Brown – Ed.)