Sunsets Over the West Once Again

11/07 Preparing for Month of Turtle Madness

I am now leaving the realm of whales and interring turtle territory. During the Mackay coal trestle job, most of the delays were caused by migrating humpback whales, particularly the mothers with their calves as they traveled close to shore (although the majority of the population migrates close to shore in Eastern Australia). After reading parts of the management plan put in place by Chevron for the Gorgon project on Barrow Island, turtles are going to be the main culprit for delays. The island offshore of Western Australia is riddled with several species of nesting and horny sea turtles.

 In case you’re not familiar with sea turtles, there are six distinct species of marine turtles inhabiting the waters of Western Australia, a small subset of what may have been a diverse and wide spread group of taxa based on fossil records. Three of these species haul themselves up onto the gently sloping beaches of Barrow Island each year to dig a hole in the sand and lay their eggs; Hawksbill (Eretmochelys imbricate), Green (Chelonia mydas), and Flatback (Natator depressus). The other three species include the Loggerhead (Caretta caretta), Olive Ridley (Lepidochelys olivacea), and the unique Leatherback (Demochelys coriacea). Just to relate this information back to home, the Leatherback is the only sea turtle regularly spotted off Central California. It’s unique because it lacks a hard carapace, and instead has a sheath of leathery skin embedded with many small keratin deposits (at least I think they are made of keratin, can’t remember what they are called either). All of these species are either considered endangered, vulnerable, or data deficient.

The life cycle of sea turtles in a nutshell

- Incubation of eggs takes 6-13 weeks, sex of the embryo is determined by the temperature of the sand.

- Hatchlings typically emerge at night. This could be due to several selecting forces, including predator avoidance and the reliance of light cues to determine the direction of the ocean (star light is brighter over the ocean than on land, which is why light pollution has been targeted as a risk for sea turtles).

- Hatchlings swim directly out to sea where they develop in offshore waters. They may spend 5-30 years at sea developing before they return to their natal beaches.

- Once sexually mature, turtles migrate between feeding and nesting waters every 1-2 years.

- Mating occurs near shore along nesting beaches, females stay in this area for a longer period than the males. Basically males mate and get the hell out of there; females stick around to produce several clutches of eggs during a single breeding season.

- Females use their pectoral flippers to drag themselves up the beach just beyond the high tide line, and use their rear flippers to excavate a hole for the eggs.

- Clutches of around 100 eggs are deposited in the hole, and the female uses her pectoral flippers to cover the hole and spread the sand so that it’s less obvious to predators (isn’t evolution great).

- Once the female has repeated this process possibly 3-4 times during the breeding season, she makes her way offshore again to feed in more productive waters.

So you can see why there is a need for dedicated marine fauna observers on a vessel that is actively sucking up hundreds of cubic tones of sediment in an area ridden with pregnant, mating, and immature sea turtles. Not only are they vulnerable to ship strikes at the surface, they will often rest for many minutes on the bottom, which puts them at risk of being sucked up the dredger. Unfortunately they are so efficient at holding their breath they are often extremely difficult to spot, since they only spend fleeting moments on the surface. At least one turtle has already been sucked through the dredging unit. If a turtle ends up in the hopper (where the spoils are temporarily stored), it will be my job to go in and determine its status (dead or alive), and if dead take samples for sexing and genetic work of the victim.

Although it won’t just be turtles around off of Barrow. There are still potentially a few migrating humpbacks around, dolphins as usual are everywhere (although they won’t be halting operations for dolphin sightings), numerous sea snakes living in the adjacent reefs, and hopefully some interesting bird sightings.

Currently I’m waiting in the Brisbane airport again for my flight to Perth. I will be arriving close to midnight. I had a blast hanging out at Mindi’s house surfing arguably the best waves in the world. I managed to fit one last surf in this morning at Snappers with her green single fin pin tail. I’ll sold on pintails now, the turning capabilities are awesome, so I’m glad my latest board waiting for me back home is a pintail. Five more weeks left until my trip home, still open for ideas about what to do when I get back (aside from the obvious surfing).

11/08 Highlights of my flight to Perth.

- I think the woman sitting next to me was the zombie form of the mom from “Shaun of the Dead”, I had to do a double take when I had a glimpse of her face.

- Water started dripping heavily from the emergency exit where I was sitting. I figured it was condensation but alerted the flight attendant anyway, who assured me the doors integrity had not been compromised.

- Flew through a massive electric storm over central Australia, one cloud in particular was constantly lighting up like a strobe light. There is almost zero light pollution in the middle of the inhospitable central part of the country, so the stars were crisp and the clouds vivid in the flashes of light. The turbulence was intense at times.

- Virgin Blue doesn’t offer pillows or blankets even on their long overnight flights, and the cabin is as cold as beer from the freezer, don’t fly with them if you have a choice (although it appears you don’t want to fly with Qantas at the moment either).