Dynamics of Priacanthus hamrur (Forsskal) exploited off Saurashtra coast

Bull’s eye landings off Saurashtra reached a peak of 3813 tons in 1999 with a catch rate of 4.3 kg per haul. The group is represented by a single species, Priacanthus hamrur (Forsskal). Gut content analysis revealed P. hamrur to be a carnivorous fish with a preference for pelagic crustaceans and fishes. Spawning females were encountered from March to December and the length at first maturity of female P. hamrur was 198 mm. Recruitment to the fishery takes place with two peaks annually - one in January-February and a minor one in October-November. A common length-weight relationship for both sexes was obtained with a = 3.481x105 and b = 2.83498. The von Bertalanffy growth equation was derived as Lt = 360.35 [1-e-0.56(t+ 0.1013)] and the length attained by the fish at the end of 1 to 4 years were estimated as 165, 249, 296 and 324 mm. The length growth performance index was obtained as !’ = 4.86 and the longevity, tmax was estimated as 4.44 years. The mortality co-efficient Z, M and F were 2.35, 1.14 and 1.21, respectively and exploitation rate, E was 0.51. Stock assessment studies reveal that the present average annual catch can be increased by 764 t to reach the MSY of 4996 tons

Interaction corrections at intermediate temperatures: dephasing time

We calculate the temperature dependence of the weak localization correction in a two dimensional system at arbitrary relation between temperature, $T$ and the elastic mean free time. We describe the crossover in the dephasing time ${\tau_\phi(T)}$ between the high temperature, $1/\tau_\phi \simeq T^2 \ln T$, and the low temperature $1/\tau_\phi \simeq T$ behaviors. The prefactors in these dependences are not universal, but are determined by the Fermi liquid constant characterising the spin exchange interaction.Comment: 4 pages, to appear in PRB, minor errors corrected, added reference

Record landings of cephalopods by trawlers at Veraval during first quarter of 2009

Cephalopods represent one of the most important exploited marine fishery resources at Veraval. The cephalopod landings in Gujarat increased by more than two folds from 0.234 lakh t in 2002 to 0.49 lakh t in 2006 (Mohanraj et al., 2009), with a concomitant increase in catch rate from 5.05 kg h-1 in 2003 to 14.74 kg h-1 in 2006. The cephalopod resource was constituted mainly by Loligo duvauceli, Sepia pharaonis and S. aculeat

Whale shark fishery off Veraval

The occurrence of the whale shark Rhiniodon typus Smith is considered a rarity and hence, most of the publications on the whale shark are restricted to its stranding, incidental catch and length measurements. Compagno (1984) reported that commercial harvesting of the whale shark is practically non-existent. However, Rao (1986) observed existence of a small harpoon fishery for the whale shark in Veraval (Saurashtra coast). Recently, there has been a remarkable increase in effort as well as catch. There are no records to indicate a directed fishery for the whale shark elsewhere in the world. The objective of this study is limited to reporting the existence of the whale shark fishery at Veraval

In-plane Magnetoconductivity of Si-MOSFET's: A Quantitative Comparison between Theory and Experiment

For densities above $n=1.6 \times 10^{11}$ cm$^{-2}$ in the strongly interacting system of electrons in two-dimensional silicon inversion layers, excellent agreement between experiment and the theory of Zala, Narozhny and Aleiner is obtained for the response of the conductivity to a magnetic field applied parallel to the plane of the electrons. However, the Fermi liquid parameter $F_0^\sigma(n)$ and the valley splitting $\Delta_V(n)$ obtained from fits to the magnetoconductivity, although providing qualitatively correct behavior (including sign), do not yield quantitative agreement with the temperature dependence of the conductivity in zero magnetic field. Our results suggest the existence of additional scattering processes not included in the theory in its present form

By-catch of the gastropod Tibia spp. in gillnets operated along Gujarat coast

The rocky coastal belt of Gujarat possesses an enormous potential resource of lobsters. Gillnets are regularly operated for lobster along the coast of Mangrol, Porbunder and Muldwarka. Gastropods such as Tibia maculata and Tibia curta occurred in large quantities as by-catch along with lobsters. Other gastropods such as Archipecten sp. and Murex sp. also make their occurrence in small quantities

On the unusual landing of juvenile black pomfret at Veraval and Mangrol landing centre of Gujrat

Pomfrets form an Important component in the fishery off Mangrol and Veraval. They are landed by trawl nets and monofilament gill nets. The silver pomfret Pampas argenteus Is locally called "Vichhuda" and the black pomfret, Formio niger is called "Halva". The former dominates the pomfret fishery with peak landings in the monsoon and post monsoon period. The black pomfret does not show any regular pattern of landing

Record size of Oriental sole (Euryglossa orientalis) (Bloch & Schneider, 1801), caught off Nawabunder, Gujarat

E. orientalis largest ever recorded oriental sole landed in Nawabunder Fishing Harbour in Gujarat caught by Dol net

Flourishing trade of air bladders at Okha, Gujarat

The swim bladders of eels (Muraenesox talabonoides Bleeker), ghol (Protonibea diacanthus Lacepede) and koth (Otolithoides biauritus Cantor) are of best quality and fetch very high market price owing to the huge export demand. Fish air bladder is mainly used for making isinglass. Considerable quantity of eel, ghol and koth are landed at Okha by trawlers operating on the rocky bottom (18 m depth) off Jakhau. Around 500 trawlers having an overall length of 40 to 45 ft, powered with 80 - 105 HP engines are actively engaged in the fishing of eel, ghol and koth. The fishing trip lasts for 7 - 10 days with 4 - 6 hauls of 3 h duration per day depending on whether they fish during only day or both day and night. The trawlers carry on an average 10 to 12 nets having length of 35 - 40 m with cod end mesh size varying between 8 and 15 mm

Bumper catch of spiny lobsters by trawlers and gill netters at Okha, Gujarat

During the post-monsoon months of September and October in 2007, an estimated 900 t of spiny lobsters Panulirus polyphagus worth of Rs. 67 crores was landed by trawlers and gill netters at Okha and Rupenbander