Friday, June 24, 2005

Loggerhead Turtle Sighting!!!

(Edited on 25 June 2005)

This is basically a draft, but I wanted to go ahead and get this out there... if I update it, I will note that fact here.

Things to know and think about:
(Please read the following few paragraphs even if you don't read all of what I have to say about my experience after that).

Loggerhead turtles don't start reproducing until they are about 30 years old.

Each nesting female will make 3 to 4 nests per year consisting of an average of 120 eggs per nest.

Each female will nest only once every 3 or 4 years so the turtles seen nesting this year are returning for the first time in a few years.

This average of 120 eggs per nest is down from 126 in the average nest just 6 years ago.

Most years see an average of 45-75 nests on the beach of Edisto Beach State Park but last year there were only 20 nests. Last year saw a record low in every area where Loggerhead nesting is monitored. The number of nesting females is currently declining at a rate of 3% per year.

Only 1 out of 1200 hatchlings live to adulthood. This number is down from approximately 1 per 1000 just 6 to 10 years ago.

There is a light ordinance on Edisto Beach (although it is unenforced by the local law enforcement authorities), and all lights are supposed to be out after 10pm. The ordinance is in place for two reasons: 1. Female turtles looking for a place to nest prefer dark beaches (remember that this behavior dates back to prehistoric times when who knows what was waiting for them on the beach during the daylight). 2. The young hatchlings will travel overland to the brightest thing that they can see when they emerge from their sandy nests about three hours after hatching from their eggs.

Most years Edisto Beach State Park has had a "false crawl" rate of about 20% but this year that percentage is up to almost 50%. The term "false crawl" refers to those times when a female turtle starts to make a nest and then aborts for whatever reason. Sometimes the females will return to land within a couple of days to try again, and other times they will just dump the eggs in the water at sea, where they die. Each nesting attempt costs the female an enormous amount of energy, so after a couple of attempts the female can not afford to continue to expend the amount of energy needed to successfully get on land, dig a nest, lay her eggs, cover and hide the nest, and then return back into the ocean. Most false crawl events occur as a result of human interference. Light and movement will make the female nervous until after she starts laying her eggs. Once she is laying she will continue laying as long as anyone nearby stays behind her. Just tonight we passed 2 groups of people who were out on the beach illegally, looking for Loggerheads after the beach was closed. There were also two vehicles that showed up on the beach, shining their lights down the shoreline and possibly scaring off potential nesters.

Long line fishing is a major threat to turtle populations. It is estimated that many hundreds of large sea turtles are drowned each year as a result of this indiscriminate method of fishing.

Leatherback turtle populations have declined 95% during the last decade. There are estimated to be only about 3000 nesting females in existence now... down from 80,000 in the 1990's.

What a tragedy.

Here is a description of my experience this morning watching a large loggerhead (whose carapace measured 46 inches and who probably weighed between 250-300 lbs) lay 160 eggs.

It is about 4:00am on Friday morning and boy have I had a fun night. I went to Edisto Beach State Park on Edisto Island to go on a Loggerhead Turtle tour that they give on Tuesday and Thursday nights. Edisto Beach is one of a relatively few places where the Loggerhead still nests because the park's portion of the beach is relatively undeveloped and is, for the most part, unlit and unpopulated.

Our group went into the lecture hall located at the campsite gift shop / nature center at 9:30pm, where the rangers taught us about the Loggerhead turtles, their current status and the many natural and man-made threats to their survival. It was an extremely informative, albeit alarming lecture; and I will be posting some of the information from that talk towards the end of this post.

We departed the lecture hall and headed out towards the beach, immediately outside the door, at about 10:15pm. No flashlights or flash photography was permitted on this tour, so it took a few minutes for our eyes to adjust to the darkness. Leading the tour was one of the park rangers and their resident "Turtle Intern". They walked about 15 feet ahead of the group to spot turtles coming in from the water, or potential turtle trails leading to nesting sites.

Edisto State Beach is only about a mile and a half long - but it has the highest concentration of nesting loggerheads on the coast because of the ideal circumstances found there. Our guides told us that tonight the conditions were right and that the chances were high that we would not be disappointed. The turtle intern had only seen 4 turtles so far this year, (and he did mention that he has yet to see one laying eggs on Tuesday night - so he always volunteers to lead the Thursday night tours).

We walked northward on the beach for about an hour. At one point there were bright lights flooding the beach from a vehicle that was driving illegally on the beach close to the gift shop (lights which were even brighter than those visible over a mile away from the beach front restaurant that had its lights on in violation of the local ordinance), so the ranger left to go get that vehicle off the beach. We stayed with the intern, and headed to a point beyond which only about 20% of the turtle nestings have occurred.

At this point the intern left us, as a group, on the beach to quietly watch the incoming waves for any signs of turtles. He raced ahead to scan that portion of the beach for any possible nesters. The nearly full moon was just rising in an orange-yellow haze on the horizon. The stars were still bright, soon to be outshone by the brilliance of the moon. I think I saw a few satellites zooming across the sky as I lay on my back with my eyes gazing into the universe waiting for the return of our resident turtle expert.

The ranger returned before he did and soon he was back as well. We headed south now, back towards the camp grounds. On the way back we encountered a group of four people who were walking on the beach illegally, looking for turtles themselves. They were made to join the group, and were told that they could leave once we reached an access point for the campsite.

At about 11:30 the ranger gave us the signal (for about the sixth time) that meant that "turtle-sign" may have been sighted. We had been instructed to back up about 20 feet when she gave us the hand signal, and we did so. The ranger and the intern came back and told us that they had spotted a female coming to shore (only the females ever do return to shore), and that we would be waiting where we were for about 30 minutes until after she started laying her eggs.

We lay in our chosen spots in the sand - 20 people waiting to get the word that we could continue down the beach to where this female turtle was preparing a nest for her eggs. The moon was large and rising, sometimes obscured by clouds and sending beams of golden light from behind them. I found myself examining the shadows on the moon and trying to visualize "the man" on the moon. I thought that I might be able to make out a form that resembled the face of Old Man Winter blowing the winter winds into a frenzy... but this night was calm and almost balmy.

Finally the turtle expert came back and split us up into two groups of about ten people and had us wait on the signal (a flashing of the ranger's red keychain-style laser light). I was in the second group so I went back and lay in the sand with my desert camo floppy hat forming a barrier between my head and the sand.

The turtle was angled facing up the beach towards our group, so as people were leaving to approach her, they made a large "U" towards the water, coming back up to approach her from behind. Once the turtle is laying her eggs, she is pretty much oblivious to anything going on as long as the noise level is kept down and she isn't approached from the front.

Our two groups were able to get directly behind her and as close as two feet from her. We could see her laying her eggs. She would lay some one at a time and some 2 or 3 at a time. She was averaging about 1 egg every second or two. It was fascinating to watch. Every minute or so, a deep sigh would escape from her as she rested for a few seconds from her labor. She had barnacles on her shell and sometimes when that carapace would scrape the sand that had piled up behind her, a momentary glow from some oceanic bio-luminescent organism would light up, taking center stage before fading away into darkness once again.

This turtle dug a relatively shallow nest. At a certain point it became obvious that she had so many eggs that the nest would be over-full which would result in eggs being crushed if she were allowed to continue on her own. The ranger and the intern started grabbing turtles eggs and placing them in a 5 gallon bucket. They were able to get about a third of the eggs out of the nest before the female began covering the nest with sand. She covered the nest using her flipper-like legs and her huge carapace to move and flatten the sand. When she was almost finished, she began flinging sand all around her with her legs to make the area where she had made the nest less conspicuous.

The turtle started to move, and we observers were now all standing and angling ourselves so that we were always behind her. She had been facing north on the beach while laying her eggs; but she turned around and headed south away from the nest and then headed out towards the water leaving tracks behind her that looked like tractor tire tracks. She was breathing heavily and once she got going there was no stopping her. Her body rocked from side to side as she used her legs that are specialized for swimming to lift her body and push it forward through the sand. Each step was taxing her energy, but they came quickly, and soon she was entering the water as the waves of the high tide welcomed her back to her domain. Four or five waves washed over her as she continued to lumber along over the sand. Then she was gone.

We watched as she surfaced three or four times in the moonlit trail leading off into the horizon. Her head and the front of her carapace forming a dark black bust against the shimmering golden backdrop. She would blow out a heavy breath each time before taking in the next, as she headed out towards the open water, where the life that only she knows was waiting.

This particular female had come in on Tuesday to try to make a nest but did not lay any eggs on that occasion. Our guides were not sure why this "false crawl" happened on that night but they thought it might have been due to the fact that she had been unable to find a good location as the place where she started digging had too many shells for her to dig deeply into the sand. Each female will make 3 or 4 nests during the years when they are nesting; and the females will only nest once every three or four years. When the females have a "false crawl", they may try to come back and lay again in a few days, or they may just dump their eggs at sea, where they will die. Luckily this female was able to lay her eggs on this night, and the specialists were able to save her eggs from being crushed.

The ranger and the intern moved her nest later that morning to ensure that it wouldn't get washed away by the ocean tides. This female laid 160 eggs in this one nest! (The average is 120 eggs per nest.) There is an entire strip of man-made turtle nests higher up on the dunes than the turtles usually make them. Each one is labeled and cordoned off with orange tape. This turtle's nest was #41.

What a neat way to spend the early hours of the morning!


Want to see satellite tracking of sea turtles? Want to know what to do if you find a tagged turtle?

Threats to sea turtles:

Link to the Marine Turtle Newsletter with many useful bits of information which was recommended by James, the "Turtle Intern".

Edisto Beach State Park Link

Link to a report on the types of debris found on Edisto Beach


Current Mood: contemplative