Grouper (Pisces: Serranidae) relative abundance and diversity on the west coast of India r.d. sluka 1 and s. lazarus 2 1 Millennium Relief & Development Services, 61 Mill Lane, Chinnor OX39 4QU United Kingdom, 2 Institute for Environmental Science and Social Education, 14/C3 Nesamony Nagar, Nagercoil 629001, Tamil Nadu, India We used timed underwater visual censuses to study grouper relative abundance and diversity on the west coast of India. Eighteen grouper species were observed in these surveys, including two new records for the west coast of India, Aethaloperca rogaa and Plectropomus areolatus. Cephalopholis formosa and Epinephelus faveatus were the most abundant species observed with the latter more numerous on inshore than offshore rocky reefs. Ecological and distributional notes are given for the species observed. Keywords: grouper, India, Laccadive Sea, Indian Ocean, biodiversity Submitted 24 November 2009; accepted 25 May 2010 INTRODUCTION Grouper fisheries in India have been studied extensively, resulting in much knowledge concerning the distribution, biology, and management of these species (James et al., 1996; Mathew et al., 2000). However, results of these studies have been based upon fisheries-dependent data usually carried out in deeper water where mechanized vessels fish, rather than in shallow shelf areas where traditional artisanal fisheries occur. This study reports on the first known survey of grouper resources on the west coast of India using under- water visual censuses. We examine grouper diversity and report on two new records from this coastline. Additionally, we comment on the cross-shelf distribution of Epinephelus faveatus (Valenciennes, 1828). MATERIALS AND METHODS Underwater visual censuses were conducted to determine grouper relative abundance and diversity at nine sites on the west coast of India, January–April, 2002 and September– December, 2002 (Figure 1). At least three 45-minute timed transects were conducted at each site. Sample size estimates were calculated based upon sampling at two sites (Vizhinjam N ¼ 6 transects and Muttom outside N ¼ 4 trans- ects). One observer (R.D.S.) identified all groupers to species on each transect. A search area of 5 m on each side of the observer was delineated visually by estimation after training using a measured distance. Timed swims were used rather than the conventional strip transects or point counts because groupers are relatively rare and mobile (Russ, 1984a, b; Newman et al., 1997; R.S., personal observation). One site (Melekkel) was much deeper than the others (Table 1) and it was necessary to limit two of the transects to 22.5 minutes each. This yielded grouper relative abundance and diversity by site. RESULTS Eighteen grouper species were identified from the study area (Table 1). Two of these species appear to be new records for the west coast of India: Aethaloperca rogaa (Forsska ˚l, 1775) and Plectropomus areolatus Ru ¨ppell, 1830. Two to nine species were observed at individual sites. The most abundant grouper at each site was C. formosa (8.8 – 24.7 individuals per 45 minute transect) usually followed by E. faveatus (0.3–7.7 individuals per 45 minute transect). The lower range of abun- dance for this species was observed at inshore sites. Epinephelus faveatus was over four times more abundant at inshore sites than offshore sites. Other grouper species when observed at a site were usually in lower abundance (range 0.2 – 2.6). The exceptions were Epinephelus malabaricus at Melekel and Epinephelus coiodes at Natrani which had relative abundances of 4.7 and 7.6, respectively. DISCUSSION The shallow-water grouper fauna of the west coast of India is dominated by species that are most abundant along continen- tal land masses. These species include Cephalopholis formosa, Epinephelus coioides (Hamilton, 1822), E. erythrurus (Valenciennes, 1828), E. faveatus, and E. malabaricus (Bloch & Schneider, 1801). All of the most abundant species are found throughout their ranges in silty habitats and in some cases estuaries (Heemstra & Randall, 1993). Of these Corresponding author: R.D. Sluka Email: bobsluka@hotmail.com 1 Marine Biodiversity Records, page 1 of 3. # Marine Biological Association of the United Kingdom, 2010 doi:10.1017/S1755267210000606; Vol. 3; e71; 2010 Published online