“Debris ingestion by sea turtles is a global phenomenon of increasing magnitude”

Schuyler, Q., B. D. Hardesty, C. Wilcox & K. Townsend, 2013. Global analysis of anthropogenic debris ingestion by sea turtles. Conservation Biology, open-access, early-view article (free download).

[The authors] “analyzed 37 studies published from 1985 to 2012 that report on data collected from before 1900 through 2011.

Turtles in nearly all regions studied ingest debris, but the probability of ingestion was not related to modeled debris densities.

Furthermore, smaller, oceanic-stage turtles were more likely to ingest debris than coastal foragers, whereas carnivorous species were less likely to ingest debris than herbivores or gelatinovores.

… oceanic leatherback turtles and green turtles are at the greatest risk of both lethal and sublethal effects from ingested marine debris.

To reduce this risk, anthropogenic debris must be managed at a global level.”

Global analysis of anthropogenic debris ingestion by sea turtles

Global analysis of anthropogenic debris ingestion by sea turtles

The authors raised several points about debris management:

  1. “Standardized reporting methods on debris effects on wildlife, including debris type and size, species, and life-history stage of animals affected, would go a long way toward creating a globally consistent and comparable data set.
  2. Increased efforts to understand debris effects in underresearched areas where turtles occur in great numbers (especially Southeast Asia, western and northern Australia, South America, and Africa), and in mid-ocean pelagic turtles would be beneficial.
  3. Our results show clearly that debris ingestion by sea turtles is a global phenomenon of increasing magnitude. Our finding that oceanic-stage green and leatherback turtles are at higher risk than benthic-feeding carnivorous turtles means management actions to target these species and life stages should be considered. This is particularly important for leatherback turtles that spend the bulk of their lives in oceanic waters, and are listed as critically endangered (IUCN 2012).
  4. Ingestion prevalence at stranding locations was not related to predicted debris density, likely due to the long migrations of turtles. Thus, conducting coastal cleanups will not solve the problem of debris accumulation in the pelagic environment, where animals are most commonly affected, although it is an important step in preventing marine debris input into the ocean.
  5. Anthropogenic debris is not only a problem for endangered turtles and other marine wildlife, but also affects human health and safety (e.g., discarded sharps and medical waste and ship encounters with large items). Debris also has aesthetic and economic consequences and may result in decreased tourism (Ballance et al. 2000), reduced economic benefits from fisheries (Havens et al. 2008), and damage to vessels (Jones 1995). Furthermore, debris destroys habitats and aids in the transport of invasive species (Sheavly & Register 2007). It is therefore a high priority to address this global problem.
  6. An estimated 80% of debris comes from land-based sources; hence, it is critical to implement effective waste management strategies and to create and maintain a global survey and comprehensive database of marine debris ingestion and entanglement.
  7. Additionally, it is worth engaging with industry to create and implement appropriate innovations and controls to assist in decreasing marine debris.”
Green Turtle 01
Photo by Rafn Ingi Finnsson

“Plastics Killing Terengganu’s Turtles” – Bernama, 24 Jul 2011

“Plastics Killing Terengganu’s Turtles.” Bernama, 24 Jul 2011.

“KEMAMAN, July 24 (Bernama) — Pieces of plastic floating in the ocean often mistaken for food or jellyfish by turtles may be one of the reasons for their deaths.

World Wildlife Fund (WWF)-Malaysia Terengganu Turtle and Terrapin Conservation Programme chief Rahayu Zulkifli said shards of plastic were found in the stomach of dead turtles in the state.

Thus, she urged the people, especially fishermen, to cooperate by not throwing plastics into the sea as they could kill turtles.

Speaking to Bernama at the launch of the WWF-Malaysia’s “Protect Our Turtles” campaign here today, she said WWF-Malaysia had taken various measures to increase the turtle population, including by buying turtle eggs for hatching with the assistance of the Fisheries Department.

Rahayu said leatherback turtle was considered a critically endangered species as only 10 nesting areas were found in the state since 2000 compared to 10,000 areas a year in the 50s.

The green turtle is also listed as threatened even though many nesting areas were discovered in Terengganu, she said.

About 400 people, including tourists, who attended the campaign signed a pledge to help protect turtles and will not eat their eggs.

The Terengganu Fisheries Department and the Kerteh District Heritage Society also took part in the campaign.”

Thanks to WildSingapore for the alert.

Plastic bags killing Queensland’s turtles

“Plastic bags killing Queensland’s turtles.” University of Queensland, 13 March 2008.

A group of University of Queensland researchers are urging Queenslanders to avoid littering the state’s marine environment during the upcoming Easter holiday weekend.

Led by Dr Kathy Townsend, Manager of Research and Education at UQ’s Moreton Bay Research Station, the group found that marine rubbish was the leading cause of sea turtle deaths in 2007.

“In 2007, we attended to 30 marine turtle strandings,” Dr Townsend said. “Of these, 23 percent were caused by the ingestion of marine rubbish. “This is almost double the number for 2006 in which marine rubbish accounted for 12 percent of the strandings.”

Dr Townsend said, regardless of its size, marine rubbish posed a serious threat to sea turtles. “A green turtle hatchling, six centimetres in length, washed up on North Stradbroke and died due to gut perforation through the ingestion of plastic marine rubbish,” she said.

“Its gut contained plastic bags, soft and hard plastic, and fishing line. The piece that killed the baby turtle was only about half the size of a fingernail. “Another turtle, a sub-adult, died with a gut full of plastic bags, the largest of which was over 30 centimetres long.”

Sea turtles are particularly susceptible to the effects of marine rubbish due to the internal structure of their throats and die a slow and painful death.

“Sea turtles have downward facing spines in their throats which literally prevent them from regurgitating,” Dr Townsend said. “The plastic gets trapped in the gut, preventing food from going down and the spines prevent it from coming back up.

“The trapped food decomposes, leaking gases into the body cavity and causing the animal to float. “The turtle then slowly starves to death or succumbs to other secondary life threatening conditions such as boat strike.”

Boat strikes have traditionally been the greatest cause of marine turtle strandings but, according to the group’s findings, accounted for only 17 percent in 2007.

“Plastic bags do kill and the recent federal initiative of a plastic bag levee is a step in the right direction towards helping address this problem,” Dr Townsend said.

In 2006, we highlighted this earlier report from Queensland – “Turtles choked with marine rubbish.” University of Queensland News Online, 12 Jul 2006.

Hawksbill turtle from Melaka now off Sentosa

The turtle named Puteri Pulau Upeh was ‘first spotted on 29 July 2006 as she laid 108 eggs in an unusually shallow pit which she dug, on Pulau Upeh. The remains of what appeared to be a fishing net was stuck in a crack on the back of her shell.

The fishing net and some barnacles were removed and she was tagged. It was assumed that she was a young nester.’

“A satellite transmitter was attached onto her shell on 29 August 2006, after her third nesting for the season. She was released at 2.20am the same night…”

‘She began her journey southwards on 14 September 2006 and crossed over to Singapore waters approximately two weeks later. Since February 2007, she has stayed in the southern islands of Singapore and must be feeding amongst coral reefs that still exist today.’

Visit the WWF Malaysia Satellite Tracking of Hawksbill Turtles page to find out more.