Distribution and abundance of the genus Vinciguerria (Gonostomatidae) in the DSL of Indian EEZ with a note on the biology of Vinciguerria nimbaria

In the DSL fish biomass one of the dominant genus was Vinciguerria, represented by three species such as V. nimbaria, V. attenuata and V. poweriae. The occurrence of Vinciguerria was frequent in nortliwest and southwest area of EEZ at varying depths. The average number per haul in Isaac Kidd mid water trawl (IKMT) was 149 in day and 191 in night collection. Vinciguerria nimbaria has accounted for more than 95% of the total catch of the genus. Its total length varied from 10-56 mm. The length weight relationship is log W = -5.5691 + 3.1676 log I. Invariably the species fed on copepods, ostracods, cladocerans, appendicularians euphausiids, chaetognaths, fish larvae etc. with variations in feeding intensity during day and night. About 92 % of the catch belonged to mature fishes. The species spawns only once in a year and the fecundity ranged from 140 to 770 ova in fishes of 34 - 55 mm total length

Distribution, abundance and biology of unicorn cod, Bregmaceros mcclellandi in the deep scattering layers of Indian Exclusive Economic Zone

In the deep scattering layer (DSL) the fishes have accounted for 5.4 % of the total (numerical) biomass. Juvenile fish belonging to different families were the most abundant component followed by Vinciguerria, myctophids, leptocephali, stomiforms, and unicorn cod. The "unicorn cod is represented by a single species, Bregmaceros mcclellandi (2.4%) in the total fish biomass. It occurred in 52 stations out of 445 IKMT stations. During day time the average number per haul was 21 where as in night hauls it was 29. The resource was fairly abundant along the northwest coast within the depth belt of 200 m. Biological studies on the size composition, feeding habits, and reproductive biology of the species were also carried out. The length ranged from 10-65 mm. The major diet consists of copepods, euphausiids, cheatognaths, ostracods and decapod larvae. Invariably the feeding intensity was low. The catch was composed of mostly females in maturity stages IV-V. The species spawns only once in a year. The fecundity ranged from 530 - 980 in fishes of 42 - 50 mm in total length

Electrical and optical characterization of conducting poly-3-methylthiophene film by THz time-domain spectroscopy

Using THz time-domain spectroscopy (THz-TDS), we have measured the absorption and dispersion of 7.5/(Ohm-cm) conducting poly-3-methylthiophene film from low frequencies up to 4 THz. From these measurements the complex conductance that increases with increasing frequency was obtained over this frequency range. The results do not follow simple Drude theory and are not comparable with normal metal and semiconductors; the results were well fit by the localization-modified Drude theory.Peer reviewedElectrical and Computer Engineerin

pi-Conjugation and conformation in a semiconducting polymer: small angle x-ray scattering study

Small angle X-ray scattering (SAXS) in poly[2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) solution has shown the important role of pi-electron conjugation in controlling the chain conformation and assembly. By increasing the extent of conjugation from 30 to 100 %, the persistence length (l_p) increases from 20 to 66 Angstrom. Moreover, a pronounced second peak in the pair distribution function has been observed in fully conjugated chain, at larger length scales. This feature indicates that the chain segments tend to self-assemble as the conjugation along the chain increases. Xylene enhances the rigidity of PPV backbone to yield extended structures, while tetrahydrofuran solvates the side groups to form compact coils in which the l_p is much shorter.Comment: accepted (J. Phy. Cond. Mat.

Threadfin breams and lizard fish resources in the shelf waters of the Indian EEZ

The regional and seasonal distribution and abundance of threadfin breams and lizard fish are presented as revealed by the bottom trawling operations of FORV Sagar Sampada during cruises 56-91 (1989 and 1992). The threadfin breams occurred in 49 and lizard fish in 25% of the total number of bottom trawhng stations surveyed. The most productive grounds for threadfin breams were located in the southwest coast between 8° and 15° N latitudinal zones, with the area 11775° yielding the highest average catch rate of 1794 kg/hr. Very high congregation and concentration of threadfin breams, composed mainly of Nemipterus mesoprion and N. japonicus, was observed in the southwest in 41- 80 m depth zones during southwest monsoon period. Lizard fish resources, composed mainly of Saurida tumbil and S. undosquamis were also relatively more dominant in the southwest coast than along the east coast and in the EEZ of Andaman-Nicobar islands. The size distribution of N. japonicus and A', mesoprion showed that smaller modal groups were dominant in shallower depth zones. The potential yield of threadfin breams in the southwest zone was estimated to be 2.05 x 10

Marine Fish Calendar. 4 Cochin

The article provides details about the marine fish landing at Cochin fisheries harbour, Kerala during the period 1981-1985. It was found that the majority of the landing was contributed by purse seine followed by trawlers, drift gill nets, boat seines, hooks and lines etc

Correlated conformation and charge transport in multiwall carbon nanotube - conducting polymer nanocomposites

The strikingly different charge transport behaviors in nanocomposites of multiwall carbon nanotubes (MWNTs) and conducting polymer polyethylene dioxythiophene - polystyrene sulfonic acid (PEDOT-PSS) at low temperatures are explained by probing their conformational properties using small angle X-ray scattering (SAXS). The SAXS studies indicate assembly of elongated PEDOT-PSS globules on the walls of nanotubes, coating them partially thereby limiting the interaction between the nanotubes in the polymer matrix. This results in a charge transport governed mainly by small polarons in the conducting polymer despite the presence of metallic MWNTs. At T > 4 K, hopping of the charge carriers following 1D-VRH is evident which also gives rise to a positive magnetoresistance (MR) with an enhanced localization length (~ 5 nm) due to the presence of MWNTs. However, at T < 4 K, the observation of an unconventional positive temperature coefficient of resistivity (TCR) is attributed to small polaron tunnelling. The exceptionally large negative MR observed in this temperature regime is conjectured to be due to the presence of quasi-1D MWNTs that can aid in lowering the tunnelling barrier across the nanotube - polymer boundary resulting in large delocalization.Comment: Accepted J. Phys.: Condens. Matte