U. Ganga

Catch composition, reproductive biology and diet of the bramble shark Echinorhinus brucus (Squaliformes: Echinorhinidae) from the south‐eastern Arabian Sea

Fishery and biological data are presented for the poorly known bramble shark Echinorhinus brucus (Squaliformes: Echinorhinidae), from the deep waters of the south-eastern Arabian Sea. A total of 5318 individuals from by-catch landings of deep-water bottom set longlines, gillnets and shrimp trawl fisheries operating at depths of 200-1200 m were recorded between January 2008 and December 2011 at the Kochi Fisheries Harbour (Kerala). A total of 431 individuals, from 46 to 318 cm total length (L(T)) and 0·8 to 132 kg total mass (M(T)), were examined to determine biological data for this species. The LT at which 50% were mature (L(T)50) for females and males was estimated at 189 and 187 cm LT. Litter size ranged from 10 to 36 and size at birth was between 42 and 46 cm L(T). Dietary analysis of stomach contents revealed E. brucus feeds on a variety of prey including crustaceans (69% index of relative importance, I(RI)), teleosts (25·8% I(RI)), cephalopods (1·7% I(RI)) and elasmobranchs (0·7% I(RI)). This study provides the first detailed biological data for this species and also highlights the extent of the by-catch fishery for this species in Indian waters.

Biological observations on the bristly catshark Bythaelurus hispidus from deep waters off the south-west coast of India

Biological data are presented for the poorly known bristly catshark Bythaelurus hispidus based on specimens collected from the by-catch of the commercial deep-sea shrimp trawl fishery operating in the Arabian Sea at depths of 200-500 m off the south-west coast of India. One hundred and sixty-two individuals, which ranged from 120 to 366 mm total length (L(T)), were collected for this study. Size-at-maturity (L₅₀) for females and males was estimated at 252 and 235 mm L(T), respectively. The reproductive mode of B. hispidus was aplacental viviparity, which is the rarest reproductive mode within the Scyliorhinidae and is considered to be the most advanced of the three reproductive modes occurring within this family. Dietary analysis of stomach contents revealed B. hispidus feeds on a variety of prey, primarily fishes.

Report of crocodile shark Pseudocarcharias kamoharai (Pseudocarchariidae) from deep waters off the south-west coast of India

The crocodile shark, Pseudocarcharias kamoharai previously unknown from the Arabian Sea of India is reported from the south-western coast (Kerala). The specimen is described and figured.

Notes on the Indian swellshark, Cephaloscyllium silasi (Scyliorhinidae: Carcharhiniformes) from deep waters off the west coast of India

The Indian swellshark Cephaloscyllium silasi is a poorly known deep water scyliorhinid (Carcharhiniformes) shark described from the south-west coast of India (off Kollam). Since the original description, reports of this species are absent due to rarity of specimens. This paper presents the first report of its egg case and also provides detailed morphological data about C. silasi based on recently collected materials.