First results from the CAWSES-India Tidal Campaign

The first CAWSES-India Tidal Campaign was conducted by the Indian scientific community during March–April 2006. The objectives of this campaign were: (1) To determine the characteristics of tides in the troposphere and lower stratosphere (0–20 km) and mesosphere and lower thermosphere (MLT) region (80–100 km), (2) to explore and identify what lower atmospheric processes drive middle atmospheric tides in the Indian continental region and (3) to provide information on those short-term variabilities of MLT tides that are likely to have an impact on the ionospheric variabilities and contribute to the upper atmospheric weather. Data sets from experiments conducted at the three low latitude radar sites, namely, Trivandrum (8.5° N, 76.9° E), Tirunelveli (8.7° N, 77.8° E) and Gadanki (13.5° N, 79.2° E) and fortnightly rocket launches from Thumba were made use of in this study. An important observational finding reported in this work is that the radar observations at Tirunelveli/Trivandrum indicate the presence of 15–20 day modulation of diurnal tide activity at MLT heights during the February–March period. A similar variation in the OLR fields in the western Pacific (120–160° longitude region) suggests a possible link between the observed tidal variabilities and the variations in the deep tropical convection through the nonmigrating tides it generates

समुद्रातील पिंजऱ्यात करावयाच्या मत्स्यशोतिसाठी स्थळ आणि प्रजाती यांची निवड

Cage culture is an utilisation of existing water bodies with little or no economic costs. The selection of a suitable site for a cage farm is indispensible for their effective function, particularly in relation to proper water quality within the cage and reduced environmental impacts around the cage and for the economic viability of the cage farm. The natural tolerance of species should be studied for assessment of suitable site

Vertical propagation characteristics and seasonal variability of tidal wind oscillations in the MLT region over Trivandrum (8.5° N, 77° E): first results from SKiYMET Meteor Radar

Tidal activity in the Mesospheric Lower Thermosphere (MLT) region over Trivandrum (8.5° N, 77° E) is investigated using the observations from newly installed SKiYMET Meteor Radar. The seasonal variability and vertical propagation characteristics of atmospheric tides in the MLT region are addressed in the present communication. The observations revealed that the diurnal tide is more prominent than the semi/terdiurnal components over this latitude. It is also observed that the amplitudes of meridional components are stronger than that of zonal ones. The amplitude and phase structure shows the vertical propagation of diurnal tides with vertical wavelength of ~25 km. However, the vertical wavelength of the semidiurnal tide showed considerable variations. The vertical propagation characteristics of the terdiurnal tide showed some indications of their generating mechanisms. The observed features of tidal components are compared with Global Scale Wave Model (GSWM02) values and they showed a similar amplitude and phase structure for diurnal tides. Month-to-month variations in the tidal amplitudes have shown significant seasonal variation. The observed seasonal variation is discussed in light of the variation in tidal forcing and dissipation

Turtle conservation activities in Tambaldeg village, Sindhudurg district, Maharashtra

Tambaldeg village in Devgad taluka is a famous tourist place in the Sindhudurg district. During a field visit to Tambaldeg beach on 24th April 2017, six carcasses of adult olive ridley turtle Lepidochelys olivacea and one of green turtle Chelonia mydas were observed in decomposed state. This beach is a turtle nesting site and the Forest department of Maharashtra with the support of local fishers is undertaking awareness programs for turtle conservation including hoardings displayed on conservation of turtles along the beach. Protection of nesting turtles and eggs is also undertaken by the local communities

Evaluation of Economic Impact on Juvenile Landings of Cephalopods in Mumbai Waters, Northwest Coast of India

Economic assessment of juvenile landings of 5 dominant cephalopods at New Ferry Wharf (NFW) landing centre, Mumbai was carried out during January to December, 2013. Dominant cephalopod fishery recorded include one species of squid, Uroteuthis (P) duvaucelii, three species of cuttlefishes, Sepia elliptica, Sepia pharaonis, Sepiella inermis and a species of octopus, Cistopus indicus together contributing 98% of total cephalopod landings. Estimated total annual economic gain calculated using bioeconomic model was Rs. 33.22 crores with estimated biomass gain of 4995 t per annum, if juveniles are allowed to grow up to length at first maturity (Lm)/Lmean. Among five species, C. indicus contribute maximum with 64.07 % of average juvenile catch followed by U. (P) duvaucelii (26 %), S. elliptica (23.63 %), S. inermis (23.27 %), and S. pharaonis (12.85 %). On these resources, while in S. inermis, both Lm equals Lmean indicates breakeven point for the species. The study revealed that peak spawning season of these species coincides with peak juvenile landings which may result in reduction of overall size range thus will lead to loss of fishery in economic as well as ecosystem regime. The study indicates the improvement of harvest biomass by 2.95 times which would result in generating additional revenue to the fishers by a margin of 3.71 times; if juveniles are allowed to grow up to Lm/ Lmean whichever is greater. Based on finding of present study management measures such as temporary fishing holidays at juveniles fishing grounds, feeding grounds and spawner abundance grounds which in turn allow these high valued species to contribute to the fishery with high economic gain and sustainable utilization of the resources may be adopted

An Assessment on Economic Impact of Growth Over Fishing of Commercially Important Marine Ariids Along Mumbai, Northwest Coast of India.

The economic assessment on juvenile landings of four dominant marine catfishes at New Ferry Wharf (NFW) landing centre, Mumbai, Northwest coast of India was carried out during January to December, 2013. The dominant catfishes viz. Nemapteryx caelata (19.7 %), Plicofollis dussumieri (21.5 %), P. tenuispinis (24.8 %) and Osteogeneiosus militaris (27.5 %) together contributing 93% of total marine catfish landings of the state. Among four species, the juvenile landings of N. caelata contribute maximum (93.17 %) followed by P. dussumieri (57.14 %), O. militaris (36.11 %) and P. tenuispinis (21.43 %) with the maximum landing during November to March . The bioeconomic model reveals that if juveniles are allowed to grow up to length at first maturity (Lm); an estimated total annual economic gain will be Rs. 13.15 crores with an estimated biomass gain of 1222 t per annum. The estimated total annual biomass is increased by 2.07 times with an increase in additional revenue by 3.7 times would have been realised. The results of present study suggest that sustainable harvest of these resources would have been yielded maximum economic return to the fishers. With the help of stakeholders participatory approach, management measures such as strict mesh size regulation, effort restriction on bottom trawl up to 50 m depth and awareness campign on catching juveniles and adult in particular to the oral incubated male ariids, would have been implemented during November to March to avoid growth overfishing

Note on Occurrence of Jaydia queketti (Osteichthyes: Apogonidae) from the Bycatch of Tropical Trawl Fishery

Three specimens of apogonids species of total length 72.69, 106.28 and 110.67 mm were caught off Tuticorin at the depths of 90-100 m as a bycatch on 1st January 2013 from the commercial trawler operated from Tuticorin Fishing Harbour, Southeast coast of India. In this paper, on the occurrence of Jaydia queketti was figured and the comprehensive diagnostic features of the recorded specimens were elucidated. The species of this genus Jaydia is distributed continentally and often caught as a bycatch from shrimp or fish trawl. These species are widely distributed in New Guinea, larger islands in the Coral Sea, Australia, Arabian Sea of India and also from Africa to Japan. Nevertheless, the present observation shows the occurrence of J. queketti from the bycatch of trawl fishery operated along Gulf of Mannar, Southeast coast of India

Intelligent intrusion detection in external communication systems for autonomous vehicles

Self-driving vehicles are known to be vulnerable to different types of attacks due to the type of communication systems which are utilized in these vehicles. These vehicles are becoming more reliant on external communication through vehicular ad hoc networks. However, these networks contribute new threats to self-driving vehicles which lead to potentially significant problems in autonomous systems. These communication systems potentially open self-driving vehicles to malicious attacks like the common Sybil attacks, black hole, Denial of Service, wormhole attacks and grey hole attacks. In this paper, an intelligent protection mechanism is proposed, which was created to secure external communications for self-driving and semi-autonomous cars. The protection mechanism is based on the Proportional Overlapping Scores method, which allows to decrease the number of features found in the Kyoto benchmark dataset. This hybrid detection system uses Back Propagation neural networks to detect Denial of Service (DoS), a common type of attack in vehicular ad hoc networks. The results from our experiment revealed that the proposed intrusion detection has the ability to identify malicious vehicles in self-driving and even in semi-autonomous vehicles

Survival and growth of juvenile silver pompano Trachinotus blochii (Lacepède, 1801) at different salinities in tropical conditions

The objectives of the present study were to evaluate the tolerance of juvenile silver pompano to different salinity conditions in order to determine the minimum salinity required for survival and also to study the effect of different salinities on survival and growth. Wild caught juveniles of the silver pompano Trachinotus blochii (average initial length: 4.38±0.44 cm, average initial weight: 1.6±0.09 g) were used in the experiments. The experiments were conducted in triplicate with 15 fish per tank. Control groups were maintained at 34±1 ppt. Juvenile silver pompano reared at ambient salinity (34±1ppt) were transferred directly to lower salinities (25, 15, 10, 5, 4, 3 and 1 ppt) and monitored for survival. Results indicated that the minimum salinity required for the survival of juvenile T. blochii is 4 ppt and 100% mortality was observed within 7-8 h in 1 ppt salinity. In another experiment, three salinity reduction protocols were followed and the three treatment groups were exposed to 25, 15 and 5 ppt salinity for a period of 56 days and the growth and survival were monitored. Survival and growth in terms of weight was not significantly different in the treatments from the control group except in the case of 5 ppt, which showed comparatively lower survival and specific growth rate (SGR). The results indicate that the culture of juvenile pompano might be feasible in salinities up to 15 ppt in tropical conditions