Field Identification of Tunas from Indian Waters

The Family Scombridae is one of the largest and most economically important fish family which comprises of most advanced scombroid fishes such as mackerels, tunas and bonitos with 54 valid species in 15 genera (Collette et al., 2001). Among them, tunas are one of the important food fishes exploited all over the world. Altogether 9 species in 6 genera are contributing to the Indian tuna fisheries. Indian tunas are classified into two categories such as (i) Coastal tuna and (ii) Oceanic tuna. Euthynnus affinis, Auxis thazard, A. rochei, and Sarda orientalis are considered as coastal tuna where as Thunnus albacares, T. obesus, T. tonggol, Katsuwonus pelamis, and Gymnosarda unicolor are mostly oceanic in nature

Noise Modelling in Highly Mechanised Bauxite Mines - A Case Study at Panchpatmali Bauxite Mines of NALCO

Panchpatmali Bauxite deposit is the one amongst a series of bauxite deposits which were discovered in the east coast region of India in early 1960s to put India in the 5th position in the world's Bauxite map with a total bauxite reserve over 02(two) billion tonnes and current annual production is about 4.8 million tonnes per annum which is now under expansion to 6.3 Milion tonne. Consi-dering its vast deposit containing over 300 million tonnes reserve, Panchpatmali bauxite deposit under name and style of NALCO Ltd., was picked u

Record sized Alepes vari and Nematalosa nasus

The herring scad, Alepes vari is a common pelagic fish species in the family carangidae. The species is the largest fish of the scad genus Alepes and maximum length so far recorded all over the world oceans is 560 mm TL (Froese & Pauly, FishBase 2016, http://www.fishbase.org.). During a regular field visit, an unusually large specimen of A. vari was recorded from Kalamukku Landing Centre, Kerala on 25th May, 2016. This was a male individual measuring 600 mm in total length (TL) and weighing 1.6 kg (Fig. 1)and was caught by hook and line. Young ones occasionally occur in pelagic trawls and larger ones rarely occur in gill net and hook and line catches

भारतीय जलक्षेत्र से ट्यूना की क्षेत्रीय पहचान

भारतीय जलक्षेत्र से ट्यूना की क्षेत्रीय पहचा

Transport and infrared photoresponse properties of InN nanorods/Si heterojunction

The present work explores the electrical transport and infrared (IR) photoresponse properties of InN nanorods (NRs)/n-Si heterojunction grown by plasma-assisted molecular beam epitaxy. Single-crystalline wurtzite structure of InN NRs is verified by the X-ray diffraction and transmission electron microscopy. Raman measurements show that these wurtzite InN NRs have sharp peaks E2(high) at 490.2 cm-1 and A1(LO) at 591 cm-1. The current transport mechanism of the NRs is limited by three types of mechanisms depending on applied bias voltages. The electrical transport properties of the device were studied in the range of 80 to 450 K. The faster rise and decay time indicate that the InN NRs/n-Si heterojunction is highly sensitive to IR light

Indiscriminate exploitation of juvenile black pomfret by ring seines along Kerala coast

Black pomfret, Parastromateus niger is an highly esteemed food fish with a very good demand in local and export markets. Unusual heavy landings of juvenile black pomfret was observed at the Kalamukku Landing Centre on 22nd and 23rd August 2016. On 22nd August, a big shoal of about 2 tonnes (t) of juvenile black pomfret was caught by one mechanised inboard (280 HP engine) ring seine unit. Similarly, on 23rd August about 1.25 t of juvenile black pomfret was landed by two mechanised inboard ring seine units with 440 HP engine power

Droplet epitaxy of InN quantum dots on Si(111) by RF plasma-assisted molecular beam epitaxy

InN quantum dots (QDs) were fabricated on Si(111) substrate by droplet epitaxy using an RF plasma-assisted MBE system. Variation of the growth parameters, such as growth temperature and deposition time, allowed us to control the characteristic size and density of the QDs. As the growth temperature was increased from 100 °C to 300 °C, an enlargement of QD size and a drop in dot density were observed, which was led by the limitation of surface diffusion of adatoms with the limited thermal energy. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to assess the QDs size and density. The chemical bonding configurations of InN QDs were examined by X-ray photo-electron spectroscopy (XPS). Fourier transform infrared (FTIR) spectrum of the deposited InN QDs shows the presence of In-N bond. Temperature-dependent photoluminescence (PL) measurements showed that the emission peak energies of the InN QDs are sensitive to temperature and show a strong peak emission at 0.79 eV

Field identification of yellowfin and bigeye tuna

Tunas are commercially important food fishes exploited from all the world oceans. Of the 9 species contributing to the Indian tuna fisheries, yellowfin and bigeye tuna grow to big sizes, and with superior meat quality have high export demand. Identification of these tuna species are comparatively easier in fresh condition than the iced or frozen condition due to discolouration, fin and skin damage during handling and storage process. In such cases certain internal characteristics such as length of air bladder, liver shape and striation are used. Misidentification of yellowfin and bigeye tunas occurs in several cases. The present study is based on field observations at Cochin Fisheries Harbour and uses an easy field identification key for yellowfin and bigeye tuna based on external characteristics developed by Itano (2005) and IOTC (2013). Bigeye tuna are landed stray numbers along with yellowfin tunas, at Cochin Fisheries Harbour

Comparing eDNA metabarcoding and conventional pelagic netting to inform biodiversity monitoring in deep ocean environments

The performance of environmental DNA (eDNA) metabarcoding has rarely been evaluated against conventional sampling methods in deep ocean mesopelagic environments. We assessed the biodiversity patterns generated with eDNA and two co-located conventional methods, oblique midwater trawls and vertical multinets, to compare regional and sample-level diversity. We then assessed the concordance of ecological patterns across water column habitats and evaluated how DNA markers and the level of sampling effort influenced the inferred community. We found eDNA metabarcoding characterized regional diversity well, detecting more taxa while identifying similar ecological patterns as conventional samples. Within sampling locations, eDNA metabarcoding rarely detected taxa across more than one replicate. While more taxa were found in eDNA than oblique midwater trawls within sample stations, fewer were found compared to vertical multinets. Our simulations show greater eDNA sampling effort would improve concordance with conventional methods. We also observed that using taxonomic data from multiple markers generated ecological patterns most similar to those observed with conventional methods. Patterns observed with Exact Sequence Variants were more stable across markers suggesting they are more powerful for detecting change. eDNA metabarcoding is a valuable tool for identifying and monitoring biological hotspots but some methodological adjustments are recommended for deep ocean environments

Development and Evaluation of Automated Slip and Draft Control System for Tractor

254-261A microcontroller-based Automatic Slip Control System (ASCS) and Automatic Draft Control System (ADCS) for 2WD tractors was devised to automatically alter the depth of operation to keep the wheel slip and implement draft within a prespecified range. An electro hydraulic lift link system was devised to control the depth of the implement's operation. The technology continuously checks wheel slip and draft in the field and notifies the hydraulic system, which changes the implement's depth if the wheel slip and draft exceeds the specified range. Experiments were conducted with defined slip ranges of 10–15, 15–20, and 20–25% for ploughing and cultivating activities. Field capacity and drawbar specific fuel consumption were measured as performance criteria. With the ASCS, the slip was found to range from 15–24%, versus the desired range of 15–20%, while with the current draft control system, it was found to range from 12–48% Tractor Draft Control System (TDCS). Fuel consumption was determined to be 20.13, 21.11, and 22.98 l/ha for ploughing operations with TDCS at initial depth settings of 150, 180, and 220 mm, respectively. However, ASCS resulted in a significant increase in fuel efficiency, with an 11.2% reduction in consumption. When compared to the TDCS, it consumed 4 to 14% less fuel during ploughing operations. Field capacity was increased by 3.4–14.5% due to ASCS and ADCS. The measuring efficiency of the devised system was determined to be greater than 99%