Diversity and Current Status of Grouper Fish , Epinephelus Bloch , 1793 in Indian Coastal Waters

| The grouper fish, Epinephelus Bloch, 1793 represents an iconic genus of the family Serranidae and order Perciformes. They are highly-prized food fishes intended for subsistence, artisanal, recreational and commercial fisheries throughout their geographic range. Despite their economic importance, the status of grouper fishes has been increasingly imperiled through overfishing activities. The conservation efforts have also been constrained with this highly skewed Epinephelus. Hence, in order to save this esteemed resource, effective conservation and rehabilitation strategies need to be planned and implemented in the country. However, it requires the knowledge of the current status of grouper fish diversity which is not yet carried comprehensively. Hence this study was proposed to review the systematic study of the genus Epinephelus to fill the gaps in diversity studies of India. The study also documented the present IUCN status of the listed species of Epinephelus under different categories of conservation status.


INTRODUCTION
I ndia is one of the twelve megadiverse nations in the world and well known for its biodiversity richness (Serajuddin et al., 2018) with a distinctive biogeographic marine ecoregion (Spalding et al., 2007). The Indian coastline (7517 km) with different coastal ecosystems supports rich diverse resources having considerable economic importance. The marine diverse resources represent half of all extant vertebrates with an estimation of 2443 (75.6%) valid species (Gopi and Mishra, 2015). In recent decades, there has been a massive development of the fisheries sector in the Indian waters. The vessels now extend their trawling operations into deeper waters, catching more varieties of demersal fishes including groupers. Grouper landings have been continuously increasing during the last decade (2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018) with an average of 37970 tonnes and are shown in Figure 1. The highest landings of 53924 tonnes in 2017 and the lowest of 17606 tonnes were observed in 2009. In 2018 the landings have been accounted for about 51433 tonnes (CMFRI, 2019). However, species-specific landing data were not reported for the grouper species. Because of this low degree of resolution, 61% of grouper landings are reported as "groupers nei" in FAO (2016) database. Concurrent with the increase in landings and production of groupers, there may be a chance of overexploitation and some species on the threat of extinction.
Grouper fishes are cosmopolitan, occurring in tropical and subtropical areas (Heemstra and Randall, 1993). This highly diverse fish group plays a significant role in the coral reef ecosystem as regulators of the structure and composition of communities and forms an important link in the food chain (Rao, 2009). The groupers are top predators, sedentary and usually sluggish in movement, slow growing and long-lived (Heemstra and Randall, 1993). They have white, tender and tasty meat, and commands a high price in the market. Moreover, many species have been prioritized

Advances in Animal and Veterinary Sciences
November 2020 | Volume 8 | Issue 11 | Page 1162 as potential species for aquaculture (Noikotr et al., 2013;Pierre et al., 2008). Small grouper species are highly valued in the aquarium trade and remain as one of the valuable fishery resources along the coasts of India. These features attracted many enthusiastic researchers (Ottolenghi et al., 2004;Sadovy et al., 2013). Over the past decade, a number of articles published on various aspects of Epinephelus species (Figure 2). In India, only 318 articles are published to an estimated 3386 articles worldwide. Thus, inspite of their commercial importance, the work done so far on Epinephelus species in India is scarce. A perusal of the literature shows that these fishes are being subjected to intense fishing pressure for food, ornamental display and medicinal purposes globally (Sujatha et al., 2015;Vincent, 2006). The loss of groupers can have a serious effect on local ecosystems since these fishes play an important role in the structure of rocky bottom and coral reef communities (Sujatha et al., 2015). In spite of their commercial importance, the status of grouper fishes has been threatened by overexploitation. As a result, certain species of groupers have become a matter of serious concern. Hence, comprehensive information on the current status of grouper diversity is a prerequisite for efficient management and to formulate the steps to be taken to protect these fishes towards sustainable exploitation. Hence the present study was aimed to manifest the diversity and current status of Epinephelus in Indian coastal waters by reviewing the studies carried so far on the diversity and distribution of this fish. The Conservation status of Epinephelus species under different categories was also documented.

Diversity anD Distribution of grouPers, EpinEphElus
Grouper fishes of the Family Serranidae (Order: Perciformes; Class: Actinopterygii) are represented by 16 genera and 163 species with world-wide distribution. According to FishBase, around 54 species of the sub-family, Epinephelinae and 38 species of the genus, Epinephelus have been reported from the Indian waters (Froese and Pauly, 2019). Groupers inhabit a wide variety of habitats, mainly coral reefs, rocky areas, seagrass beds, and estuaries (Darwin et al., 2018;Rao, 2009). They exhibit a wide variety of reproductive and growth strategies (Morris et al., 2000). Epinephelus species are regularly landed by subsistence, artisanal, and commercial fisheries throughout their geographic range. A significant number of studies have been carried on the diversity of groupers, Epinephelus in various ecosystems of the Indian coastal waters and are presented in Table 1. Data on the distribution of Indian groupers were collected from twelve coastal states and union territories of India ( Figure 3) which revealed the presence of 47 species of Epinephelus in Indian waters ( Table 2). The species richness against the length of the coast of all states and union territories is presented in Figure 3. The east coast represents 76.59% with 36 species, while the west coast

Advances in Animal and Veterinary Sciences
November 2020 | Volume 8 | Issue 11 | Page 1163  Pokapunt et al., 1993;Rajan, 2001Rajan, , 2015Rajan et al., 2013;Rao, 2009;Kirubasankar et al., 2013;Ramakrishna et al., 2010 represents 57 It is evident that among the 47 Epinephelus species registered in India, 40 are commercial, while the remaining species are used for aquaria, game/sport fishery, subsistence fisheries and aquaculture (Table 2). In India, rearing of groupers in brackish water aquaculture is a relatively new development as a diversification option in pond and cage culture farms and is still in R and D phase. Certain behavioral characteristics with a high degree of territoriality and site specificity are making the groupers at risk and easy targets for fishermen (Heemstra and Randall, 1993;Morris et al., 2000;Sadovy et al., 2013). In this context, groupers are emerged as a particularly vulnerable group of fishes (Ranjan, 2015 Figure 4).

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CONCLUSION AND RECOmmENDATIONS
The present study provides a complete checklist of Epinephelus species reported from Indian coastal waters. So far 47 species of Epinephelus have been reported. However, Fish Base (http://www.fishbase.org/) has shown only 38 species, including E. multinotatus which was not reported in Indian waters. Hence, the database of FishBase needs to be revised and updated to 47 species. Despite their importance for commercial fisheries, aquarium trade, aquaculture and coral reefs, these species are highly threatened by overexploitation, bycatch, and habitat loss due to degradation of coral reefs and the possible effects of climate change. These factors are also impacting the species biodiversity. To conserve these species, it is necessary to implement ecosystem-based management practices. Therefore, the following steps could be taken to improve the conservation of Epinephelus species along the coastal waters of India and elsewhere: (i) collection of landing station-wise data from commercial, bycatch, ornamental and recreational catches; (ii) genetic diversity studies to overcome taxonomic ambiguities (iii) identification of the nutrient profile and consideration of the minimum catch size to avoid depletion of the stock in future; (iv) integrated knowledge about the social, biophysical and ecological aspects of Epinephelus in a sustainable way; (v) increase efforts on education and conservation awareness in coastal tourism and communities; and, most importantly, (vi) creation of networks for marine reserves in priority conservation areas, protecting key species and habitats for their survival. This will not only pave the way for better protection of Epinephelus diversity but will also help maintain harmony in the marine community.