Studies on vibration of some rib-stiffened cantilever plates

The vibrational mode shapes and frequencies of rib-stiffened skew cantilever plates as determined by holographic interferometry are given. The effects of varying the sweep back angle, rib stiffness and aspect ratio are studied along with the influence of varying the boundary conditions at the root chord on the vibrational behavior of the plates. The study is applicable to investigating the vibrational behavior of stiffened plates often used in the design of guided rockets and missiles

First record of of unicorn sole, Aesopia cornuta (Kaup,1858)along the malabar coast

Flat fishes are very important demersal fishery resources contributing 4% of the trawl landings along the malabar coast. Flat fishes of the family cynoglossidae support the commercial flatfish fishery of malabar regeion, but the occurrence of flat fish of the family soledae is not common.The distingushing character of this species is brown colour with 14 -16 dark band edged with black, with some pale spots

First record of snaggletooth shark, Hemipristis elongatus (Klunzinger,1871) from Malabar Coast

Unusual landings of the shark,Hemipristis elongatus by multi-day trawlers were noticed for the first time along Malabar Coast in September,2003.It is aslender bodied shark with a long broadly rounded snout;large cured,saw-edged teeth in the upper jaw and hooked lower teeth protruding from mouth.Fins are strongly cured

First record of thresher shark, Alopias vulpinus, from Malabar coast with note on its fishery and biology

Thresher sharks are distributed circumglobally in the Atlantic, Pacific, Mediterranean and Indian Oceans. Thresher sharks include the common thresher (Alopias vulpinus), bigeye thresher (A. superciliosus), and pelagic thresher (A. pelagicus), the former being the largest. Unusual landings of this shark by long liners were noticed along the Malabar coast in 2005. The details of its fishery and some observations made on the biology are presented

Occurrence of cockatoo righteye flounder, Samaris cristatus (Gray, 1831) along the Malabar coast

Flatfishes are readily distinguished from all other fishes by their compressed body and head with both eyes on the same side, either on the right or left. They belong to the order Pleuronectiformes and are divided into eleven families Achiridae, Achiropsettidae, Bothidae, Citharidae, Cynoglossidae, Paralichthyidae, Pleuronectidae, Psettodidae, Samaridae, Scophthalmidae and Soleidae. The fishes belonging to the family Samaridae have eyes on the right side of head. They occur in all the oceans and about 20 species belonging to three genera are found worldwide

Bycatch and discards in commercial trawl fisheries of Malabar region

Increase in the commercial trawling in the last few decades has made direct impact on ecosystem and also on the biodiversity. Trawling kills a large quantity of ncn-targeted species and juvenile fishes. The fisherman after each haul discards a large quantity of unwanted fishes and shellfishes in to the sea. The discard rate varies in relation to the target species, season and area of operation. Trawl fisheries, are characterised by high discard rates of unwanted fish, and of juvenile or undersized commercial species. There is growing evidence that intensive fishing with trawls may alter the habitat, and affect biodiversity, community structure, species composition and abundance of both target and other species within the food web. The most recent FAO estimate sets global discards at about 25% of reported annual production from capture fisheries. The types and quantities of discards in fishing operations will depend on the species and size selectivity characteristics of the gear used in relation to the target species

First record of bandfish, Acanthocepola limbata (Valencienness, 1835) from Malabar region

The family Cepolidae comprises of 23 species of fish in five genera, all of which are found in eastern Atlantic and wide spread in central Indo-Pacific. The species Acanthocepola limbata (Valencienness, 1835) is a meso bathypelagic species distributed circumglobally. In the Indian waters, it has been recorded from Karwar (Kulkarni and Balasubramanian, 1978)

First record of ocean sunfish, Mola mola from Malabar coast

Ocean sunfishes of the family Molidae are large pelagic fishes rarely found along the south-west coast of India. Presently, four species are recognised under this family throughout the world. An ocean sunfish,Mola mola was landed in Beypore fishing harbour, Calicut on 14.12.06.It was caught in trawl net which operated north-west off Calicut at a depth of 70 m. The specimen is preserved in the museum for future reference

Rare occurrence of Japanese bigeye Pristigenys niphonia (Cuvier 1829), off Malabar Coast

The family Priacanthidae commonly inhabit rocky areas and reefs, although a few are known to inhabit open waters. Priacanthas are typically colored bright red, but some have patterns in silver, dusky brown, or black. They have unusually large eyes, suited to their habitat in deeper waters. Pristigenys is one of the genera of Priacanthidae and comprises of 3 species

Fishery of elasmobranchs with some observations on the biology and stock assessment of Carcharhinus limbatus (P. Muller & Henle, 1839) exploited along Malabar coast

Elasmobranchs are caught in trawls, gillnets and longlines along the Malabar region of Kerala and they are landed almost round the year, accounting less than 1% of the total catch. The catch of elasmobranchs during the period 2001-2011 has shown a declining trend, but towards the end of this period the fishery has improved marginally. The contribution of trawl, gillnets, longlines and other gears were 43.1%, 31.3%, 21.1%, and 4.5 % respectively. The contribution of sharks, rays and skates were 70.8%, 24.2% and 5.0% respectively. Twenty four species of sharks, 8 species of rays and 2 species of skates were recorded in the catch. Length-weight relationship was estimated for Carcharhinus limbatus and the regression equation for both the sexes was W = 0.00001486L 2.80214 (r=0.9661). The overall F: M ratio was estimated as 1:1.59; females predominated the catches in almost all months. The growth of this species is described by the equation Lt= 302 (1-e-(0.45)[t-(-1.2)]). The species grows fast during the early stages of its life. The annual average exploitation ratio (E) is estimated as 0.74 which is higher than the optimum exploitation rate estimated. The present study showed that C. limbatus is heavily targeted, hence this species is at risk of being overexploited and is in need of immediate management