The Overlooked Importance Of Marine Turtles (Part 1 Of 2)

Sea turtles are one of the longest living reptiles that have roamed our seas for the last 110 million years. Albeit being the oldest living reptiles, most marine turtle species are going extinct. Mostly due to human impacts such as climate change and egg poaching. In addition to that, sea turtles are hard to study. This is because they are solitary creatures and spend most of their time under water. Hence, most research done over the decades are through observations at sea which have provided useful insights. To date, six out of seven sea turtle species are at risk of going extinct. The dwindling numbers of sea turtles are alarming. As a result, their extinction will pose a threat to both ecosystems and beach systems. Reason being, they’re important contributors in maintaining the balance of both these systems through their diet and nesting patterns.

Malaysian Beaches, A Home To Marine Turtles

Four of seven known species of marine turtles call Malaysia home. They are the green, hawksbill, leatherback and olive ridley species. Unfortunately, they are all facing extinction due to dwindling numbers and have been placed on the International Union Conservation of Nature (IUCN) Red List. As such, we have numerous non-profit organisations and hatcheries that contribute to the conservation of sea turtles. I’ve had the opportunity to participate in a turtle conservation programme under the Sea Turtle Research Unit (SEATRU). It’s a research programme hosted by Universiti Malaysia Terengganu (UMT). But first, let’s take a dive (pun intended) and learn about marine turtles, its importance and the effectiveness of conservation programmes.

The Four Main Types Of Marine Turtles Found In Malaysia

Each turtle species has its own characteristics to differentiate them from one another. We’ll elaborate on the four main species.

1. Green Turtle

The name green turtle doesn’t derive from their shell as commonly believed. Rather, it derives from the colour of their cartilage and fat. The green turtle is the only herbivorous species among the four. They are also one of the largest sea turtles growing up to 180kg in weight and 120cm in length. They often come ashore to nest on Malaysian beaches from April to August.

2. Hawksbill

Named after their pointed beaks, the hawksbill makes easy meals of sponges, picking them up between corals. The other distinction is their thin, brightly coloured shell with elaborate patterns. Commonly found throughout the world’s tropical oceans, they also feed on jellyfish and sea anemones too.

3. Leatherback

The leatherback turtles are the largest sea turtle species. As their name suggests, the leatherbacks get their name from their shell which has a leather-like texture. What’s impressive is that they are also the most migratory turtle species, crossing both the Atlantic and Pacific Oceans.

4. Olive Ridley

Olive ridley is the smallest turtle species and only grows to about 70cm in length and 50kg in weight. In contrast to green turtles, olive ridley lends their name from the colour of their shell, an olive green colour. Olive ridley turtles are the most abundant of all marine turtles in the world. Despite their abundance, its population is still vulnerable. This is due to the limited amount of nesting spots around the world. They also often migrate thousands of kilometres to nest and feed.

Marine Turtles As A National Malaysian Heritage

Malaysia has a long coastline. The west coast of Peninsular Malaysia faces the Straits of Malacca. The east coast of the peninsular, and the Borneo states Sabah and Sarawak faces the South China Sea. Due to its geographic location, Malaysia boasts many beautiful beaches. Some of the more popular beaches include those on Redang Island, off the coast of Kuala Terengganu. These beaches are the turtles main landing sites to land and lay their eggs. To name a few: Sabah, Sarawak, Terengganu and Pahang.

One of Malaysia’s national heritage are sea turtles. This is because they’re one of the main attractions of the tourism industry. As surprising as it is, the marine-based tourism generates a generous amount of revenue for the country’s economy. Promotional tourism videos for Malaysia often heavily feature marine turtles as a species unique to Malaysia. There’s a very strong integration of marine turtles in the Malaysian identity. In fact, you can even find images of these majestic creature on the MYR20 banknote, and the 1995 stamps.

The Importance Of Sea Turtles

The population of marine turtles declined many decades ago. That leaves us with little to no baseline to compare with the current state of our ecosystem. Without that baseline to compare against, we may have overlooked the importance of marine turtles to the ecosystem. Each turtle species has a role in maintaining the marine ecosystem.

As mentioned, the herbivorous green turtles feed on seagrass. This helps increase the productivity and nutrient content of seagrass blades. As for hawksbill turtles, they actually impact the overall diversity of reef communities. Hawksbill turtles feed on sponges which grow between corals. This prevents sponges from dominating reef communities and limiting the growth of corals. Unfortunately, the decline in leatherback turtles have resulted in the increase of jellyfish population. Leatherbacks are significant consumers of jellyfish which makes them the top jellyfish predators. With their rapid decline, the shift in balance of species dominance from fish to jellyfish is alarming. In consequence, this has resulted in lower fish numbers available for commercial fishing.

Nutrient Cycling Of Marine Turtles’ Eggs

Other than being great contributors towards the marine ecosystem, female sea turtles in particular, play a part in beach systems. This happens through nutrient cycling of the turtle eggs. Nesting beaches are usually low in nutrients. So, this indirectly helps improve conditions of nesting beaches. The importance of nutrient cycling is to also maintain the community dynamics of other animals, insects, and plants on nesting beaches. In general, there are four ways in which the recycling of sea turtle eggs back into beach systems can occur:

1. Hatched eggs leave nutrients in the form of eggshells after the hatchlings return back to the sea;
2. Eggs that fail to hatch are great as compost for the beach. This in turn contributes to a more nutritious nesting site;
3. Consumption of turtle eggs by predators such as monitor lizards, hence nutrients would come in the form of excreted waste; and
4. Lastly, the penetration of nutrients from the turtle eggs into roots of surrounding plants.

Are You A Sea Turtle Lover And Have An Interest In Conservation Activities?

Did you know that for every 1,000 hatchlings, there is only one lucky hatchling which survives? Ever wondered how marine turtle conservations work? And what threats marine turtles face? In the next episode, I’ll be sharing my eye-opening experience with Sea Turtle Research Unit (SEATRU). My first time ever volunteering at a turtle conservation programme, hosted by Universiti Malaysia Terengganu (UMT). Read here about snorkelling and diving at Mabul Island where you have the chance of seeing sea turtles up close.