Zanzibar Sanctuary Helps Sea Turtles Adapt

After a late night flight and a long, pothole-laden drive through small coastal hamlets on deserted streets, I arrived in the town of Nungwi at 3:45am on the northern tip of the Zanzibar.  I awoke four hours later, feasted on a breakfast of pineapple, watermelon, eggs and baked beans, and walked to the beach. Any extended trip focused on marine conservation is inevitably marked by extensive opportunities for swimming in the ocean. I alternatively scuba dive or snorkel daily and rarely miss a chance for a quick dip in its healing waters.

After a salt-water bath, I ambled down the coast past hundreds of fishing dhows while listening to the sound of boat building in the distance. A small fleet of elementary age girls in hijabs and black robes played games in the sand, while their mothers sat in small groups cleaning fish from the men's catch the night before.  The fishers, who had been offshore casting and hauling in their nets all night, were nowhere to be seen.

One of the few men on the beach was Mtimbange (below) who told me the sad story of how he lost his brother and his fishing boat in a big storm a month earlier. It was pitch black on a moonless night and he swam for his life, following the direction of the current until he saw the local lighthouse which guided his path home. He never saw his brother again and was pondering a future without the livelihood that having his own boat provided. He said that the storms had become more sudden and violent in the past few years. I bought Mtimbange some coffee and we talked fishing and religion.  When I asked him what he believed, he responded that he was undecided. “My father was Christian and my mother was Muslim. They were both good people and loved one another till they died, so somehow both must be right.” When I told him about my project, he asked if I was going to visit the turtle sanctuary. I had heard of it but didn’t know the way, so he led me there and introduced me to Moses William, one of the marine center staff.

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The Mnarani Marine Turtles Conservation Project was started in 1993 by the Eco & Culture Tours Zanzibar at the site of a tide pool that is inshore from the beach. Originally created to house the turtles that were accidentally caught in the fishers' nets, it has since expanded into a breeding program. The villagers mark and monitor the local turtle nesting sites and newly hatched turtles are brought to the Sanctuary. They are raised there for two years, which dramatically increases their chances of survival, before they are released into the deep blue sea.

As Moses explained, despite a thirty-year ban on catching sea turtles or harvesting the eggs for food, poaching is not uncommon, and all of the local sea turtle species are still endangered. Nungwi's primary economic activity is net fishing and sea turtles inevitably end up as 'bycatch' in their nets. But the main reason for the slow recovery - according to Moses - that the average female green sea turtle doesn’t reach sexual maturity for 10-25 years and lays eggs only once every 2-4 years during her 100-year lifespan.  The majority of these hatchlings won’t survive into sexual maturity, so reproductive recovery is a slow process. The Sanctuary gives the local turtles a better chance of long-term survival and educates tourists who pay a small fee to keep it funded.

Frederick & Mtimbange

Frederick & Mtimbange

A few mainland Tanzanians that I walked the beach with that afternoon

A few mainland Tanzanians that I walked the beach with that afternoon

The life of a turtle is adventurous! After 6-8 weeks in the egg, baby sea turtles crawl to the surface of the beach. If they are lucky enough to avoid predation in the shell or on their voyage into the ocean, they get whisked away by the currents for upwards of ten years. These are called the “lost years”, because we now little about them. At some point in their aging process – around the size of dinner plates – they return to coastal areas and forage. Once they reach sexual maturity they migrate to the beaches where they were born to mate, continuing the cycle. Therefore, the majority of the turtle eggs laid at the beaches in Nungwi came from turtles that hatched at the same beach.

Moses expressed concern about the effects of climate change on reproduction. The tides in this part of Zanzibar are dramatic, as shallow gradient beaches characterize the coastline: the downhill slope out to sea is very gradual.  Even a small rise in sea level could have disastrous effects for turtles nesting on local beaches, as the beach is not wide enough at high tide to support even an inch of additional sea level rise. By collecting the eggs and raising them turtles themselves, the Sanctuary ensures that the eggs avoid this fate.

Green sea turtles at seven weeks

Green sea turtles at seven weeks

Moses William with sea turtles almost ready to be released into the ocean.

Moses William with sea turtles almost ready to be released into the ocean.

Other organizations are trying alternative methods. For instance, Turtle Island Restoration Network is currently implementing a feasibility study in the Hawaiian Islands to transplant eggs laid in the Papahanaumokuakea National Monument to a former nesting site on the island of Lanai near Maui. If slim beaches face flooding threats during nesting season, perhaps we can assist them by introducing them to steeper, wider beaches. If successful this method could be replicated elsewhere as well.

I am one to believe that nature knows best. If a species – given the right quality and quantity of habitat – can adapt on their own to climate change, I prefer this option. Human beings have done too much damage to the natural world to ever be able claim that we know better than nature how to conserve and help it thrive. But these days quality and quantity are both increasingly limited. I am open to solutions where we can assist our marine life to support their adaption to the irrevocable changes that our reliance on fossil fuels has had on the planet. We have already irrevocably changed the surface and function of the earth. In a climate changed world, I am glad that global organizations like TIRN and local sanctuaries like Mnarani are out there helping turtles thrive.

The anatomy of a sea turtle

The anatomy of a sea turtle

Moses feeding the turtles

Moses feeding the turtles

 

 

Frederick Smith