Assessing the status of marine debris at Keeri Beach, Mannar, Sri Lanka, using the Clean Coast Index (CCI)

Abstract

Marine litter is a globally increasing environmental issue, contributing to the degradation of coastal aesthetic quality. Mannar is one of the five districts of Sri Lanka’s Northern Province. Its western side boasts the golden sandy Keeri beach. This beach is used for fishing, local tourism, and recreational activities. Clean Coast Index (CCI) serves as a tool for evaluating the actual cleanliness of the coast, categorizing beaches as very clean (0-2), clean (2-5), moderately clean (5-10), dirty (10-20) and very dirty (>20). The main objective of this study is to assess marine debris, quantify and categorize the types present on the beach, eventually assess beach cleanliness using the CCI, and compare the results for fishing and non-fishing sites. Data were collected on fishing and non-fishing sites using the throwing quadrat method (100 m x 10 m x 8 quadrat = 8000 m2) along designated transects which were identified using random plot sampling. The mean debris quantities were analyzed using a paired t-test in Minitab to evaluate the significant differences. A total of 736 macro debris (classified into single-use and multi-use plastic waste) were identified from both sites. Among them, 109 (~20 %) and 627 (~80 %) macro debris were collected, respectively, from the fishing and non-fishing sites. The paired t-test revealed a mean difference of -122.7 (p-value = 0.02, with a 95 % confidence interval), statistically indicating that the non-fishing site holds the maximum macro debris. The study showed the classification of the non-fishing sites as dirty (12.54) and fishing sites as clean (2.18), according to CCI. The structured questionnaire survey was conducted among available local fishermen in the community using the convenience sampling method. This included the Likert scale, multiple choice, and open-ended questions covering sections of demographic information, marine debris status, fishery status, and tourism activity. The results revealed concerns about marine debris and its sources and impacts. Based on the responses, tourism activity was identified as a major contributor (50 %) to high debris accumulation on the beach, while no significant effects on fishery resources were observed. The main sources of marine macro debris have been imputed from improper waste disposal and fishing activities. The finding underscores the need for targeted cleanup and management interventions, such as implementing proper waste disposal systems, conducting an awareness campaign, and educational workshops for the community, particularly in non-fishing areas, to mitigate the environmental impacts.