Mapping ecological distribution of chondrichthyan species in western India

The west coast of India, a part of the Arabian Seas Region, is home to a rich biodiversity of chondrichthyan species and is the highest contributor to India’s shark exports. All life stages of sharks are targeted by... [ view full abstract ]

The west coast of India, a part of the Arabian Seas Region, is home to a rich biodiversity of chondrichthyan species and is the highest contributor to India’s shark exports. All life stages of sharks are targeted by fisheries and caught as bycatch. In spite of increased mechanization and improved efficiency of fishing gear, there has been a 20% decline in fisheries catch, a typical sign of declining fish populations. Protecting and preserving remnant populations is thus imperative. However, knowledge of chondrichthyan species distribution is sparse, which makes it challenging to establish marine sanctuaries to protect chondrichthyes. Our research focuses on mapping seasonal chondrichthyan species distributions through non-invasive environmental DNA sampling in collaboration with local fishing communities in Gujarat, India. Fishers collect water samples using sterile sampling methods, along transects in several locations in Gujarat and record GPS location and depth for each sample collected. These water samples are filtered to obtain sloughed cells from skin or scat of free swimming marine species in the area. DNA is extracted from cells and chondrichthyan specific universal primers are used to amplify multiple genetic loci within the mitochondrial genome. Field-based sequencing techniques are used to determine species identities. Using these methods, we have identified the presence of previously unreported Chondrichthyes at three locations in Gujarat. Our ongoing and future efforts are focused on identification of ecologically important chondrichthyan habitats and on co-developing a draft MPA establishment plan in collaboration with fishing communities.