Marine Debris and its effects on Sea Turtles

Transcription

1 Inter-American Convention for the Protection and Conservation of Sea Turtles 7 th Meeting of the IAC Consultative Committee of Experts Gulfport, Florida, USA June 4-6, 2014 CIT-CCE Inf.2 Marine Debris and its effects on Sea Turtles This informative document was prepared by the IAC Secretariat and Dr. Diego Albareda, Scientific Committee delegate from Argentina. This document summarizes the main negative effects of marine debris on sea turtles and their habitats. It includes some recommendations that might be considered by IAC Parties and a brief description of international instruments that address this issue. Due to the increasing scientific information available on marine debris and sea turtles, which suggest the extent of this problem for the region, delegates of the Scientific Committee have proposed the revision of this topic to bring to the attention of the IAC Parties in the form of a draft Resolution. The rationale behind this it to support IAC Parties and strengthen their sea turtle conservation efforts in the area of environmental education related to marine debris management by highlighting the negative effects that they have on sea turtles and their habitats, as well as highlighting the value of sea turtles as charismatic species and their potential to contribute to the cultural transformation of society in the matter of waste management. Thus, we request the Consultative Committee of Experts to carefully review this document and provide their opinion on the following: a) Determine if the topic of marine debris and its impact on sea turtles and their habitat could be further developed in to a Draft Resolution to be presented at the IAC 7 th Conference of the Parties (COP7).

2 INTRODUCTION Marine debris includes any anthropogenic, manufactured or processed solid material, regardless of its size, discarded, disposed of or abandoned in the environment, including all materials discarded into the sea, on the shore, or brought indirectly to the sea by rivers, sewage, storm water or winds (UNEP/CMS, 2011, UNEP/NOAA, 2011). This definition includes plastics, and also encompasses other types of materials such as textiles, metal, glass, paper, construction materials, and dangerous material such as asbestos, ammunitions and medical waste. Although a wide range of materials are considered marine debris, most items fall in a small number of types such as glass, metal, paper and plastic. The last one being the most abundant and the one with mayor interaction with marine organisms (Secretariat of the Convention Biological Diversity, 2012). Marine debris are found in all marine habitats of the world, all latitudes and depths. The marine debris subject, the pollution of coastal and marine ecosystems and their interactions with biodiversity is a complex, multi-sector problem with economic, social and environmental implications. In terms of the environmental implications, marine debris is considered a major factor which contributes to the loss of biodiversity and one of the least understood and more complex to study (National Research Council, 2008). Marine Debris and Sea turtles and their habitats Given the wide range of types of marine debris, their interaction with sea turtles and their habitats can be classified in different ways such as: Ingestion Marine debris ingestion, specially small-sized plastic, has been reported in all sea turtle species, with distribution in all geographic areas and in all life stages (Gonzalez Carman, 2013; Schuyler et al., 2013; Secretariat of the Convention on Biological Diversity, 2012; National Research Council, 2008). Recent studies suggest that the probability of plastic ingestions by green turtles (Chelonia mydas) and leatherbacks (Dermochelys coriacea) has significantly increased over the last decade (Schuyler et al., 2013). For example, in a study performed in the Southwestern Atlantic on juvenile green turtles, 90% of the 62 specimens examined had ingested anthropogenic debris (Gonzalez Carman, 2013). Similarly, high percentage of ingestion was reported in Florida, USA (Bjorndal, 1994). Marine debris ingestion may have lethal and sub-lethal effects, both of significant importance on the sea turtles species. Ingestion may produce blockage of the digestive tract by foreign objects which are the main lethal effect caused by marine debris. Likewise,

3 the ingestion of plastic bags may also cause an obstruction on the digestive tract, causing injuries to the mucosa/lining and altering its normal functioning. This causes floatability malfunctioning in the turtles, disabling them from submerging and feeding normally. This in turn, causes a gradual deterioration in the turtles physical state which leads to their death after a slow agony. Furthermore, the ingestion of debris may cause intoxication and tissue destruction because of toxic substances that may be taken inside the organism. Especially micro plastics (<5 mm approximately) that are easily ingested by this species. Marine debris ingestion may not only cause lethal effects on sea turtles as a consequence of the obstruction of the digestive tract. Different research has shown sub-lethal effects of marine debris ingestion as a consequence of nutrients dilution. This happens when the debris (no nutrients) replaces the nutrients content in the intestine which may cause a direct effect on the individual nutrient intake when the amount of debris in the intestine is greater than the volume of food. In consequence, there is a reduction in the amount of nutrients which interfere directly with the growth and reproductive rate. Thus affecting sea turtles populations and their conservation. Entanglement/Entrapment Many forms of marine debris like packages, ropes, tires and abandoned fishing gear posed series threats to sea turtles; after getting caught on this debris, the individual's mobility is diminished and some drown or die from lack of food. Also, lacerations can lead to death by sepsis. On the other hand, marine debris may cause the alteration, degradation or destruction of key marine and coastal habitat for sea turtles such as foraging areas and nesting beaches. At the same time, these materials may be used as dispersal vehicles via rafting for invasive species over large areas. Although the marine debris issue is not fully studied, the existing information of its impact on the sea turtle species is sufficient to support immediate actions to control and mitigate this environmental issue. Existing Strategies for Marine Debris management The management and reduction of marine debris is intricate due to the complexity of the nature of the issue, reflected in aspects such as: accumulation of debris in habitats far from the source, their persistence in the environment, lack of regulatory framework for the productive chain and the high clean-up cost. Because of this, global measures taken to prevent this problem focus on prevention at the source of origin, to reduce the amount of

4 debris that goes into the sea and reduce the amount of sea-based debris introduced into the sea from abandoned vessels among others. Beside, actions have been identified to prevent debris accumulation. Among the main strategies for the prevention and reduction of marine debris are: 1. Implementation of education and outreach programs on i) the importance of reducing, reusing and recycling material in order to avoid/reduce the production of debris; ii) the importance of keeping streets, storm drains and other areas near rivers and other waterways, free of debris; iii) raise awareness among boaters and other interest groups on the importance of properly stowing their debris on board and avoid disposing materials in the sea. 2. Creation of legal frameworks aimed at strengthening legislation to support management, prevention and reduction of marine debris. Along with the capacity building to apply these regulatory frameworks. 3. Promotion of periodical clean-up campaigns in critical areas such as watershed, rivers and other waterways to reduce the accumulation of trash that may end in the sea. 4. Use of infrastructure to improve rain water management and reduce the discharging of solid waste into waterways. Additionally, International Conventions and other organizations have addressed the issue. Such as the Convention of Migratory Species (CMS) through its 10.4 Resolution on Marine Debris adopted at the 10 th Conference of the Parties (Bergen, November ) and the Convention of Biological Diversity through a technical document on the matter.

5 BIBLIOGRAPHY Bjorndal, K., et al. (1994) Ingestion of Marine Debris by Juvenile Sea Turtles in Coastal Florida Habitats. Marine Pollution Bulletin, Vol.28, No. 3 pp Committee on the Effectiveness of International and National Measures to Prevent and Reduce Marine Debris and Its Impacts, National Research Council. (2008). Tackling Marine Debris in the 21st Century.p.p.224 Foley, A., et al. (2007). Characteristics of a Green Turtle (Chelonia mydas) Assemblage in Northwestern Florida Determined During a Hypothermic Stunning Event. Gulf of Mexico Science. pp Gonzalez Carman, V., et al. (2013). Young green turtles, Chelonia mydas, exposed to plastic in a frontal area of the SW Atlantic. Marine Pollution Bulletin Vol. No. 28.pp Secretariat of the Convention on Biological Diversity and the Scientific and Technical Advisory Panel GEF (2012).Impacts of Marine Debris on Biodiversity: Current Status and Potential Solutions. Montreal, Technical Series No. 67, 61 pages. Schuyler, Q., et al. ( 2013). Global analysis of anthropogenic debris ingestion by sea turtles. Conserv. Biol.. UNEP/CMS. (2011). Resolución 10.4: Marine Debris, adopted by CMS COP 10 (Bergen, November, 2011). UNEP/NOAA, (2011).The Honululu Strategy. A Global Framework for Prevention and Management of Marine Debris.pp. 57.