A Review on Hidden Subterranean (Hypogean) Ichthyofaunal Resources of India along with IUCN Status, Threats and Its Conservation Strategies

Subterranean habitats are one of the most peculiar and mysterious ecosystems on earth, yet we still have very less information about their biodiversity. These animals often live in extremely nutrient-limited environments. Consequently, most of the subterranean fish species are relatively small in size to survive on limited food resources. We present here a systematic checklist along with IUCN conservation status and a comprehensive account of the diversity, distribution, threats and suggest conservation measures for the Indian subterranean fishes. A total of 18 species under 5 orders, 8 families and 7 genera are listed from the secondary data. According to the IUCN Red List status, nine subterranean fish fauna are listed under the Not Evaluated (50%) category, five Data Deficient (27.78%), two endangered (11.11%), and only one species come under the Critically Endangered (5.56%) and Least Concern category (5.56%). Several anthropogenic stressors including agriculture, overexploitation, deforestation, habitat disturbance, hydroelectrically plans, invasive species, human-fish conflicts, climate change, sand mining and un-ecofriendly tourism are threatening these underground fishes. Nevertheless, there have been only a few studies on subterranean fish fauna, partly because many subterranean occur in tropical regions, sometimes in caves of difficult access, where there are few local researchers. It is necessary to promote throughout society the importance and urgency of studying and conserving subterranean resources to preserve their ecosystem services.