It is well established scientific knowledge that turtles may maintain the health of coral reef systems by grazing on sponges, which, if left to grow unchecked, outgrow the corals, cover them up and suffocate and kill the reef. Because of this, researchers believe that declining numbers of turtles may be a factor in the inability of reefs to resist increasing pressures from pollution, algal overgrowth, overfishing and climate change.
Importance of Marine Turtles in maintaining healthy ecosystems
Green turtles are largely herbivorous, and their constant grazing on seagrasses increases the healthiness and growth rate of seagrass beds. Some turtle’s species, which forage in the open ocean throughout their life, are the top predators of oceanic jellyfish. Jellyfish, in turn, eat larval fish. As the numbers of these species plummeted in the oceans, jellyfish numbers may increase locally and eat more larval fish, leaving fewer fish to grow into adults. A wide variety of marine ecosystems dependent on these fish, and indeed commercial fisheries, may end up suffering from this cascading effect.
Marine turtles return to the shore during each nesting season and lay hundreds of eggs. In doing so, they provide a source of nutrients that plays a vital role in coastal dune ecosystems. The eggs and hatchlings provide food for many predators and humans, and the empty shells and eggs that don’t hatch provide nutrients that can be recycled by invertebrates and micro-organisms. In turn, these nutrients are used by plants, which help stabilise dune structure. In this way, turtles transport nutrients from productive far-away feeding grounds to nutrient-poor coastal ecosystems and play a vital part in their stability.
Cultural and Historical significance of marine turtles
Marine turtles have been of major cultural, traditional, social and economic significance to many coastal communities around the world and The Gambia and Gunjur are no exception.
Throughout history, turtle meat and eggs have provided valuable sources of sustenance for the locals, while shells are highly sought after for medicinal, ceremonial and ornamental purposes.
Food and Medicinal demand of Turtle eggs
In the years gone by, large amounts of turtle eggs are consumed in The Gambia and the sub-region. The exploitation of eggs initially started as a traditional source of food within local communities. Customary beliefs also had it that turtle eggs have aphrodisiac and medicinal properties. These beliefs have encouraged a huge commercial market for the eggs in The Gambia and across the globe and put severe pressure on the marine population.
The expansion of European civilisation across the globe in the 1600s and 1700s depended in part upon adequate food supply for ships’ crews. Marine turtles were a ready and seemingly inexhaustible source of food. The northern hemisphere’s subsequent fondness for turtle soup in the Victorian era led to large-scale commercial turtle harvesting, putting many turtle populations under even more severe strain. Turtle harvesting and canning factories were still operational in places like Western Australia as late as the 1970s.
If not Genetic, what Determine a Marine turtle’s gender?
Male turtles stay at sea for all of their lives, and only females ever come ashore to lay their eggs on sandy beaches – interestingly, the same beach where they were born. Unlike many animals, a marine turtle’s gender is not genetically determined but is dependent on the temperature of the sand where the egg develops. Female hatchlings result from higher temperatures, while cooler temperatures produce males. Different beaches and different positions in the nest can both affect the eventual gender of the hatchling.
Threats faced by nesting turtles and what CETAG is doing to mitigate that
Like humans, marine turtles take many years to become reproductively mature – it may take up to 25-30 years for some species before a female can lay eggs. In between hatching and returning to their nesting beach to lay eggs, most marine turtles migrate vast distances.
Leatherback and loggerhead turtles, for example, travel across the entire Pacific Ocean between feeding and nesting grounds – a journey of over 12,000 kilometres one way or more than one-third of the way around the world. Other species stay much closer to home – for example, the flatback turtle does not move outside the waters of the northern Australian continental shelf.
The long time to reach maturity and the many natural dangers and man-made face by hatchlings and juveniles through their incredible migrations mean that as few as 1 in 1,000 eggs may survive to adulthood.
As a result of this low survival rate, conservations efforts are essential to maintain the healthy population of these ecologically significant marine species. This is where the work of CETAG come to the fore. Once nesting turtles come onshore to nest, they are confronted with a mirage of challenges; ranging from but not limited to hunters for mother turtles and their eggs, animal predators and unsuitable habitat as a result of coastal erosion and high tides. For the past fifteen years, The Gunjur Conservation group led by wildlife experts such as; Sulayman Jabang, Lamin Keita, Nyima Touray and Nyana Jammeh were involved in small scale but very effective turtle conservation effort in and around The Kombo coast, from Gunjur to Kartong and Gunjur to Sanyang. In October 2020, they joined hand with other environmentalist groups, Eco lodges and a local NGO in Gunjur to improve their capacity and human resources to complement their efforts.
What can you do to help?
Your holiday in the Gambia and supporting the Gunjur Sea Turtle Eco Experience is one of the best ways you can personally help in promoting a sustainable alternative to the negative impact of mass package tourism in The Gambia. The sea turtle conservation program in Gunjur is geared towards raising environmental awareness, nurture grassroots economies, and social development. Spending a day out with this team of conservation volunteers is a real-life experience you cannot afford to miss in your life.
Learn more about the volunteering opportunities and join in as the season of nesting begins.