Background

Being a tropical country, India is blessed with a rich diversity of flora and fauna and put among the mega biodiversity countries of the world, however, with a fragile ecosystem (Yadav, 1997). As a result of increasing anthropogenic activities, marine ecosystems are currently facing an accelerated loss of populations and species, with unknown consequences (Worm et al., 2006). There is mounting concern toward the expanding human impact on marine biodiversity that has occurred in the course recent years (Jackson, 2010). The conservation status of species and the regional Red Lists are prepared by International Union for Conservation of Nature (IUCN).

According to the classification of IUCN, the species were grouped into nine based on population size, the rate of population decline, the area of geographic distribution, the degree of population and distribution fragmentation. The groups are Extinct (EX), Extinct in the wild (EW), Critically Endangered (CR), Endangered (EN), Vulnerable (VU), Near Threatened (NT), Least Concern (LC), Data Deficient (DD), Not Evaluated (NE) (Guidelines for Using the IUCN Red List Categories and Criteria, 2017). According to IUCN (1996), the formally stated goals of the Red List are (1) to provide scientifically based information on the status of species and subspecies at a global level, (2) to draw attention to the magnitude and importance of threatened biodiversity, (3) to influence national and international policy and decision-making, and (4) to provide information to guide actions to conserve biological diversity (CITES, 2000).

Kerala lies at south west coast of India bordered west by the Arabian Sea. Kerala has a coastline of about 590 km and the Exclusive Economic Zone (EEZ) extends up to 200 nautical miles far beyond the continental shelf, which covers an area of 218,536 km² (Kerala Marine Fisheries Statistics, 2013). Kerala coast has major fisheries of the shrimps, cuttlefish, sardines, mackerels, anchovies, soles, sharks, rays etc. The present study has been carried out as a part of research project on “Marine Biodiversity along Kerala coast”, funded by Ministry of Earth Sciences, through Centre for Marine Living Resource and Ecology. Among the various species landed, we have made a survey of IUCN Red Listed species and the findings of the same are reported in this manuscript.

1 Materials and Methods

1.1 Study area

For the present study, we have selected three major fish landing centres of south west coast of India namely Neendakara of Kollam district (8°93’N, 76°53’E), Munambam of Kochi (10°18’N, 76°17’E) and Beypore of Kozhikode district (11°17’N, 75°80’E). Neendakara fishing harbour is one of the top fishing harbours of Kerala. Munambam fishing harbour is one of the best examples of hygiene and a thriving fishing village of the district. Beypore is an old port of Kerala and famous fish landing centre in Kozhikode district.

1.2 Data collection

The samples were collected seasonally and harbour visits were made on fortnight basis during 2014 January to 2015 December (2 years). The fishes identified were listed according to IUCN Red List status and also the different schedules of the Indian wildlife (Protection) Act and in the appendices of Convention on International Trade in Endangered Species of wild flora and fauna (CITES) (IUCN Red List 2017-3). All images of the fishes were captured in-situ with a canon power shot G16 camera. Preserved specimens were examined for detailed identification (Misra, 1952; Ebert and Mostarda, 2013; List of Fish Species; Fish Base). Individual surveys were conducted to obtain any unreported historical data. Historical records of sharks in the Indian coasts were obtained from the following sources: (a) fishery-dependent inspection for the description of the elasmobranch fisheries (b) ichthyological collection of Kerala state. In this survey, we collected data from coastal fisheries for demersal and pelagic species, and from semi oceanic fisheries for pelagic species.

2 Results and Discussions

A total of 206 marine fishes were recorded from the three selected harbours of south west coast of India (Figure 1) during a study period of two years. All of the identified species were checked for Red List status and found 73 of them were listed under 2017-3 IUCN Red List (Table 1; Table 2; Table 3). Combined season wise landings of Red Listed finfishes were presented in Table 4. All the species observed in this study were known species. All the identification is done with classical taxonomy and also with the help of some expertise in the taxonomic field.

Anguilla anguilla was the only critically endangered species collected during study period. As per the previously published Red Lists, since 2008 this species considered as critically endangered. From Kerala, there are no detailed landing reports of Anguilla anguilla. But occurrence of Anguilla bengalensis in the pokkali fields of Kadamakkudy, Kerala reported by Mumthaz and John in 2017, which was listed as a near threatened species. Our seasonal studies showed that Anguilla anguilla landings were present in harbours of three study areas. Comparing to the recent landing of Eels with previous years, the results showed that in 2016 the landings were decreased than two previous years (CMFRI, 2014; 2015; 2016). According to the recent reports of IUCN, its worldwide population is also decreasing. Barriers to migration, body condition, climate change, changes in ocean currents, diseases and parasites are the major threats which affected the existence of Anguilla anguilla (IUCN, 2017).

Seventeen species of finfishes which coming under the class Chondrichthyes were found during study period. Out of these seventeen species, five were sharks and five were rays. Two endangered species, Rhincodon typus and Sphyrna lewini, the vulnerable guitarfishes; Glaucostegus granulatus, Glaucostegus obtusus, Rhina ancylostoma and vulnerable rays; Himantura uarnak, Maculabatis gerrardi, Pateobatis bleekeri, were observed during two year study period. The comparative study of annual landing reports of CMFRI from 2013 to 2016 showed that the landings of sharks and rays were increased in recent years. But the presence of skates was noticeably decreased from 545 tonnes to 83 tonnes per year (CMFRI, 2013; 2014; 2015; 2016).

The whale shark Rhincodon typus is the largest species of fish and has a circumglobal distribution in all steamy and mild waters, except the Mediterranean Sea (Compagno, 2005; Compagno et al., 2008). Fishing pressure on sharks is high in Indonesia and India and many taxa are overfished (Blaber et al., 2009; Ferretti et al., 2010). As mentioned above the landings of sharks were increased may be because of highly sophisticated fishing methods and overfishing. The data published by IUCN reported that current population trend of most of the sharks was decreasing. Policies connecting to safeguarding and conservation of whale sharks include Appendix II of Convention for the Conservation of Migratory Species of Wild Animals (CMS, 1999) and Appendix II of CITES. In 2001, whale sharks were conserved in India under Schedule I of the Indian Wildlife (Protection) Act, 1972.

Out of nine vulnerable species, two species of seahorses, Hippocampus kuda and Hippocampus trimaculatus were cited under Appendix II of the CITES. Seahorses are valuable species in trades for Chinese medicines. H. trimaculatus is one of the most traded species in the international seahorse trade (Evanson et al., 2011; UNEP-WCMC, 2012a). Since 2003 the status of these species remains as vulnerable. Trade surveys conducted by Project Seahorse during 1995-2000 reported that while the global trade of seahorses appears to be increasing, but the fishermen and other surveys reported a considerable decline in seahorse availability globally. Seahorses are threatened by habitat destruction (Vincent et al., 2005) such as coastal development, destructive fishing practices, diminishing seagrass beds due to trawling and destruction of mangroves which leads to increased pollution and siltation in surrounding marine waters (Short et al., 2011). Along with these sea horses Anguilla anguilla, Rhincodon typus and Sphyrna lewini, were also included in Appendix II of the CITES.

Ten near threatened (NT), Thirty nine Least Concern (LC) and Twelve Data Deficient (DD) species were the other identified specimens. Ten species of groupers; Epinephelus chlorostigma, E. diacanthus, E. fuscoguttatus, E. latifasciatus, E. longispinis, E. malabaricus, E. merra, E. radiatus, E. tauvina, E. undulosus were collected from study areas during the study period. Compared to 2013 the grouper landings increased 34.1% in 2014 (Rekha et al., 2015). E. diacanthus, was the dominating grouper species. E. radiatus, E. tauvina, E. undulosus were observed in Kollam harbour only in postmonsoon season.

Sardinella longiceps which is commonly known as Indian oil sardine and they are highly migratory and schooling species. Sardine was the single major contributor towards the total catch, but showed a noticeable decrease in total landings throughout the study period. In our study, this species was observed in harbours of Kochi in premonsoon season and also observed in harbours of Kozhikode in postmonsoon season. The annual report of CMFRI-2015 mentioned that the annual landings of oil sardine in Kerala coast was 10,290 tonnes/year, in 2013 it was 246,841 tonnes/year but in 2016 it reached up to 45,958 tonnes/year (CMFRI, 2013; 2014; 2015; 2016). Based on 2017-3 IUCN Red List, Sardinella longiceps is a least concerned species but the recent reports showed a declining trend in landings along Kerala coast. Climatic changes in oceans, marine pollution and increased anthropogenic activities may be the main reason for the decline in marine fish landings (Times of India, 2015; The Hindu, 2016).

Habitat destruction spread of diseases, marine pollution, increased anthropogenic activities, targeting of specific species because of increased commercial values and unsustainable fishing practices lead to the extinction of species. In fishery sector, the accidental catch of protected species is a common problem. The officials of protected resources have to modify fishing gears to minimize the bycatch. As a consequence of difficulty in continuous monitoring of marine ecosystem, the extinction reports are very less.

3 Conclusions

Conservation of threatened species is essential for the sustainability of the ecosystems. The effective method for conservation is creating awareness about the overexploitation and illegal marketing of products from the threatened marine organisms. Protection of habitat, controlled human activities by increasing number of protected areas and restoration of threatened species through artificial methods can reduce the population destruction.

Authors’ contributions

Vincent P.D., Soumya Krishnankutty and Ajith Joseph C.: Fish sample collection, analysis species identification and preparation of manuscript. Dr. A.A. Mohamed Hatha has contributed in the design of the study, mobilization of research grants, review and finalization of the manuscript. All authors read and approved the final manuscript.

Acknowledgements

We would like to thank Dr. Ravinesh R., Department of Aquatic Biology, Kerala University, Thiruvananthapuram, for rendering help during species identification and valuable comments on the manuscript. The authors are also thankful to Ministry of Earth Sciences and Centre for Marine Living Resources and Ecology for the financial support to this research.

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