Marine Litter - Threat to Our Marine Wild

Oceans are incredible habitats that provide immense benefits in tourism, fisheries and coastal protection. Coral reefs, mangrove forests and other near-shore marine habitats are systems that are closely tied to people’s socio-economic and cultural values. Over the last several decades, significant changes have taken place; over-fishing, destructive fishing, climate change and pollution.

Marine litter is any type of man‐made solid waste which deliberately or accidentally pollutes oceans, seas and coastlines. Marine litter is found in all the accessible world's oceans and seas, even in remote areas (Valavanidis & Vlachogianni, 2011). Marine solid waste can float on the sea surface or sink on the seafloor and some can be washed to the sea coastlines (beach‐litter). Marine litter can spread very easily to the coastline as a result of marine transport, tourism and uncontrolled discharge of municipal waste in illegal landfills.

Floating debris can be transported over substantial distances by winds and currents, resulting in the deposition of items from many different countries on beaches around the world. Litter in the marine environment originates from two main sources: rubbish dumped from ships at sea and land-based sources such as runoff from rivers, waste water systems, wind-blown litter and recreational litter left on beaches (Coe & Rogers, 1997).

Litter along the beach

80% of litter found in marine is plastic items (Valavanidis & Vlachogianni, 2011). Floating plastic waste wash out into the oceans from rivers and sewers, while larger plastics are broken down into smaller fragments that last for years (Smithers, 2016). The slow biodegradability nature of plastics makes it the most pervasive, persistent and hazardous form of litter in the marine environment. It is estimated that 4.8-12.7 million tonnes of plastics enter the world’s oceans every year due to littering and inadequate waste management. This figure is deemed to increase to as much as 28 million tonnes a year by 2025 (Smithers, 2016).

In Kenya, seasonality, North East Monsoon (NEM) and South East Monsoon (SEM), is a major factor affecting transport and deposition of litter along the coast yearly. The SEM is characterized by high rainfall, river discharge, terrestrial runoff, fast currents, wave energy and wind energy. During this season, transport of debris from the land and in the sea is high. These parameters are reversed during the NEM season and it is characterized by deposition of litter along the coast (McClanahan, 1988). During NEM, Somali currents occur relatively close to the coast, travelling at low speeds of 0.7–1.0m/s. This makes it possible for marine litter to be deposited offshore in the north of the WIO region, particularly, on the northern Kenyan coast (UNEP & WIOMSA, 2008).

Beach Cleanup exercises need to be done so as to remove litters that if swallowed by marine life, they enter the food chain and disrupt fragile ecosystems. Although, this will not happen overnight, a temporary solution is needed, thus beach clean-up activities need to be carried out frequently along the Kenyan Coast. In this context, the marine debris has direct impacts on the sea turtles both in the sea and on land.  

Sea turtle feeding on a plastic bag

Turtles are known to consume plastic bags mistaking them for jellyfish and the bags clog their stomachs, often leading to death from starvation. Turtle hatchlings face incredibly low survival odds as they mount long and difficult trek to the water to survive. The faster they reach the water, the more likely they are to live, but physical objects like trash prolong their movement diverting them from the shortest route to the sea. This result in hatchlings following a path parallel to the ocean that may increase chances of mortality.

Debris in our coast if not removed, can be harmful and even fatal to all manners of marine wild, can damage our country’s economy and even become a human health hazard. 

Effects of Climate change on Sea turtles

Sea turtles are found in all oceans except for the Polar Regions. They mostly can be found in coral reefs and some species are known to travel between oceans. Sea turtles are generally found in the waters over continental shelves. During the first three to five years of life, sea turtles spend most time in the pelagic zones floating in seaweed mats. Green sea turtles, which are common species nesting in Lamu, in particular are often found in Sargassum mats, where they find shelter and food. Once the sea turtle has reached adulthood it moves closer to the shore. Females will come ashore to nest on sandy beaches during specific seasons usually between Aprils to Septembers in Lamu, North coast of Kenya.

Green turtle hatchling - Photo: Hassan Bwanamkuu

Sea turtles worldwide face a variety of threats that have threatened their existence. The top five threats that endanger sea turtles are:

• Fisheries By-catch – Worldwide, hundreds of thousands of sea turtles are accidentally caught in shrimp trawl nets; long-line hooks and gillnets every year.
• Pollution – Plastic pollution, oil spills, and chemical runoff have all impacted sea turtles.
• Coastal Development – sea turtles are dependent on beaches for nesting. Uncontrolled coastal development, vehicle traffic on beaches and other human activities directly destroy or disturb sea turtle nesting beaches around the world. Feeding grounds such as coral reefs and sea grass beds are damaged and destroyed by activities onshore, including sedimentation from clearing of land and nutrient run-off from agricultural activities uphill.
• Direct Take/Poaching – Sea turtles and their eggs are taken by people (both legally and illegally) in many parts of the world for consumption and use of shell material for handicrafts and jewelry. 
• Lastly, Climate change – Sea turtles' lives are dictated, in large part, by heat: subtle temperature variations shape their embryonic development, determine their sex, and influence their growth and nesting activity. So how might turtles respond to warmer beaches and warmer oceans as global temperatures rise? This is a great question that needs to be answered so as to ensure the existence of these vulnerable species is not risked.

Just to take you back and give you a sneak-peek of turtle’s life. Sea turtles use both marine and terrestrial habitats during their life cycles, the effects of climate change are likely to have a devastating impact on these endangered species. A rise in the sea level will impact sea turtle nesting beaches directly. Sea turtles' memories are "imprinted" with a magnetic map of the sandy beach where they hatched. This gives them the unique ability to return to that same site decades later to repeat their ancient nesting ritual. With melting polar ice caps and rising sea levels, these beaches are beginning to disappear. The direct impacts of sea level rise include losing beaches, ecologically productive wetlands and barrier islands.

An increase in nesting beach temperatures will also have an impact on sea turtles. Because sea turtles are reptiles, they rely on the temperature of the sand in which the eggs incubate to determine the gender of the hatchlings in a nest. Typically, the eggs in the lower, cooler, part of the nest will become males, while the eggs in the upper, warmer, part of the nest will become females. With increasing nest temperatures, scientists predict that there will be more female than male hatchlings, creating a significant threat to genetic diversity.

Warmer ocean temperatures are also likely to negatively impact food resources for sea turtles, and virtually all marine species. Coral reefs, which are an important food source for sea turtles, are in great danger. As a result of rising temperatures, coral reefs are suffering from a "bleaching" effect that kills off parts of the reef.

In my future blog post I will highlight to you the possible measures that need to be taken to address this issue of climate change and also how we are working in Lamu counter this major threat of climate change to help the turtles.

5 Things You Can Do To Save Sea Turtles

Making a positive difference for sea turtles in your area is as simple as following the five easy steps we have outlined below.

1. Reduce the Amount of Garbage You Produce and Clean Up Trash You See On the Beach.

Sea turtles can become tangled in plastic and trash both on the shore and in the water. Discarded items such as fishing lines, balloons and plastic bags may also be confused for food and eaten by sea turtles, often resulting in injury or death.

2. Be Aware of Sea Turtle Nesting Areas and Avoid Nesting and Hatching Turtles.

Sea turtles are cute, and therefore tempting to touch and observe – but flashlights and people disturb turtles when they are nesting, or trying to nest, on the beach. Make sure to give nesting areas plenty of space, and do not disturb females as they emerge from the ocean looking for a place to nest. Also be conscious of where nesting areas are so that you can avoid trampling the hatchlings as they head to the water.

3. Reduce the Amount of Chemicals You Use.

The chemicals you use on your lawn and in your home can actually wash into the coastal waters – killing plants and animals. It is very important to properly dispose of toxic chemicals and, even better, find alternative products such as biodegradable solutions.

4. Turn Out Lights Visible From the Beach!

Sea turtle hatchlings use light and reflections from the moon to find their way to the water at night. Artificial lighting confuses the hatchlings and causes them to head inland instead of out to sea – putting them in dangerous situations which can lead to death. Artificial lights also discourage adult females from nesting on the beach. Short of turning off your lights, you can also take measures to shield, redirect and lower the intensity of the lights on your property.

5. Volunteer!

There are countless ways in which you can make a positive difference in the lives of sea turtles. Organize a clean-up day with your friends and clear the beach of litter, give a presentation to your neighborhood or local school on things they can do to save sea turtles, and most importantly, talk to others about what they can do to make sure they are not putting these important creatures in danger.