An assessment of the past and present distribution status of the whale shark (Rhincodon typus)along the west coast of India

Abstract

Background Tounderstand the historical and present occurrence and distribution patterns of whale sharks along the west coast of India in the Arabian Sea, Traditional Ecological Knowledge (TEK) and Indigenous Technical Knowledge (ITK) questionnaire surveys were conducted during May 2012 to March 2013. The surveys were conducted in the maritime states of Maharashtra, Goa, Karnataka, Kerala and the union territory of Lakshadweep. Approach Thesurvey was targeted at active and non-active fisher-folk between the ages of 25 and 90 years to obtain information on historical and current presence of whale sharks in fishing territories across the West Coast. Results Atotal of 1703 fisher folk in 118 fishing villages were interviewed using an improvised structured questionnaire developed from the standard TEK and ITK questionnaires. Over 60% of the interviewed fishers reported having sighted whale sharks in the Arabian Sea along the west coast during their fishing activities 20–100 km from the shoreline. Sightings were most frequent in the Lakshadweep Sea followed by the coastal waters of Maharashtra, Karnataka and Goa. Four major whale shark aggregation locations in the Arabian Sea were identified: close to the coast of Malvan in the Sindhudurg district of Maharashtra, Netrani Island in Uttar Kannada of Karnataka, Minicoy and Kavaratti Island in Lakshadweep and along the Saurashtra coast of Gujarat. The whale shark aggregation locations that were identified as a result of this study were found to overlap with key marine resource productivity areas, such as paste shrimp (Acetes sp.) abundance zones. The incidental capture of whale sharks in fishery operations over the last few years were notably high along the Kerala coast followed by Maharashtra. The mean number of respondents (in each village) who had caught whale sharks using gill nets were significantly higher (Kruskal-Wallis x2 218.56, df 2, p <0.05) than the mean number of respondents (in each village) who had caught the species using either purse-seine or trawl nets. Conclusions Thesurvey results indicate a lack of awareness amongst the fishing community of the whale shark being a protected species and the ban on their capture and trade; it emphasizes the need tolaunch an intensive awareness campaign along the west coast of India. The respondents also mentioned that the most common human induced threats to the whale sharks are incidental catch in gill net, purse seine and trawl.

Shark and ray research in India has low relevance to their conservation

“…Other Management/Policy themed publications included literature on conservation campaigns and policy evaluations for the whale shark (Rhincodon typus; e.g. Premjothi et al, 2016a;Matwal et al, 2014).…”