Northwest Coast Of India Research Articles

Fishery and biology of Sepia pharaonis Ehrenberg, 1831 off Mumbai, northwest coast of India

Fishery of Sepia pharaonis by trawlers at New Ferry Wharf (NFW) during 2000 - 2011 in Mumbai waters is described. The landings ranged from 438 t (2004) to 1,763 t (2005) and the catch rate ranged from 0.17 kg/hr (2003) to 1.04 kg/hr (2005). The relationship between dorsal mantle length (DML) and total body weight (TBW) for males, TBW = 0.0008414 * DML 2.57989 and for females, TBW = 0.0009723 * DML 2.55201. Fish formed the major food item in both the sexes (87.1% in males and 86% in females) followed by prawns. Females were dominant in the catch with a sex-ratio of 1:1.24. Maximum numbers of males were mature (43.6%) while maximum numbers of females (37.2%) were spawning. The size at 50% maturity for females was estimated as 153 mm. The major peak spawning season for the species is during February to May.

Assessment of Coastal Water Quality Parameters of Selected Areas of Marine National Park & Sanctuary (Okha, Sikka & Khijadiya)

Gujarat is a state located in the North-West coast of India. It is known locally as Jewel of the West. It has an area of 196,204 km2 (75,755 sq mi) with a coastline of 1,650 km (about 990 mile). As per the Government notification of Gujarat State, an area of 457.92 km2 of MNP & S includes 148.92 km2 of 42 small and big Islands with coral reefs and mangrove forests and 309 km2 intertidal areas along the coast. Coastal area is the most dynamic and productive ecosystems, industry and tourism (Xiaojun, 2008). The physicochemical qualities of sea water are very important and critical for the health biodiversity existing in entire Gulf of Kachchh. The analysis of physico-chemical and plankton in the present study has achieved some important findings. The obtained results highlight that there is a pronounced variation in most of the water quality parameters with variation in season and geographical location.

Studies on chemical composition of three species of Enteromorpha

Studies on proximate, mineral, fatty and amino acid composition of edible Enteromorpha species, viz. Enteromorpha compressa, Enteromorpha linza and Enteromorpha tubulosa, collected from the Northwest coast of India, revealed for species-dependent nutrient composition variation. The present study showed a higher amount of sugar (51.05±1.22%), protein (19.09±0.91%) and lipid content (5.56±0.16%) E. tubulosa. Amongst the seventeen elements analyzed (Ca, K, Mg, Na, P, As, Cd, Co, Cu, Fe, Hg, Mn, Mo, Ni, Zn, Cr, Pb), all three species showed a higher amount of calcium content. E. compressa was obtained with rich amount of macro-elements (11.42±0.017g/100g dry wt), while maximum micro- and trace-elements (81.51±6.65mg/100g dry wt) were recorded in E. linza. Amino acid analysis revealed seven out of the 10 essential amino acids were present either in excess or at-par with the reference proteins. Moreover, all the three species studied possessed relatively high n-3 fatty acids; additionally they had more unsaturated fatty acids than saturate ones, except in E. compressa. Therefore, based on the present investigation, it could be stated that the three species studied could be used as food supplements to improve the nutritive value in the omnivorous diet.

First record of blue-spotted stingray, Neotrygon kuhlii from Gujarat, north-west coast of India

One female specimen of blue-spotted stingray, Neotrygon kuhlii was collected from a single day trawl catch along with other species of rays from the Saurashtra coast of Gujarat, India. The present paper describes the first record of the blue-spotted stingray from the State of Gujarat, thereby adding another species to the total recorded species list from the area.

Evaluation of feeding indices of cobia Rachycentron canadum (Linnaeus. 1766) from Northwest coast of India

Cobia Rachycentron canadum (Linnaeus. 1766) is an esteemed table fish occurring along both east and west coast of India. Feeding indices of the species inhabiting waters of the northwest coast of Indian EEZ was studied to understand the variation of its feeding intensity based on season, sex and life history changes. Monthly variation of stomach condition of cobia male, female, pooled and size wise were analyzed. In general, 56% of fishes were found in either actively fed or moderately fed state. Except during April and July they were found in actively fed condition. Analysis of occurrence of empty stomach in different length classes of fishes revealed that the percentage of occurrence of empty stomachs decreased with the fish growth. Month- wise Mean Index of Feeding intensity (MIF) and Index of Fullness (IF) values showed that cobia fed well during post monsoon periods but poor feeding activity was noticed in July. Gastrosomatic index for male, female and pooled samples of matched with the MIF and IF values. The results indicated a seasonal variation in feeding intensity of cobia. On an average, feeding intensity during July was low.

Numerical Modeling of Oil Spill Movement along North-West Coast of India Using GNOME

India is located at a very strategic point with respect to the international commercial sea routes with a large amount of crude oil traffic. Hence, the risk of oil spill occurring in the Indian waters is considerably high. In the present paper, forecasting the movement of a possible crude oil spill of 10,000 barrels at a location of latitude 21° 41′ 48.53′ N and longitude 66° 46′ 41.45″ E, intersection point of two ship routes from Kandla port and Bombay port (Kandla port of India to Yanbu port of Saudi Arabia and Bombay port of India to Ras Tanura port of Saudi Arabia) has been carried out using GNOME (General NOAA Operational Modeling Environment) model developed by Hazardous Materials Response Division (HAZMAT) of the National Oceanic and Atmospheric Administration Office of Response and Restoration (NOAA OR&R) of United States government. The governing equations for horizontal diffusion, evaporation, dissolution, dispersion etc, adopted by GNOME have been presented in the paper. The simulation is carried out for month of September 2011. It is found that the spill possibly takes 10 hours to reach Gujarat coast and 15 hours to reach Maharashtra coast. With this available knowledge, appropriate mitigation measures may be adopted before spill reaches the shores.

Wave Transformation and Attenuation Along the West Coast of India: Measurements and Numerical Simulations

Waves measured at a few locations along the west coast of India were analyzed to study modification and attenuation of wave energy in the nearshore regions. It has been found that the reduction in wave height is relatively lower (less than 10%) between two nearshore depths off Goa (25 m and 15 m) and Ratnagiri (35 m and 15 m), central west coast of India and is higher (22%) off Dwarka (30 m and 15 m), northwest coast of India. It is observed that the diurnal variation in waves decreases from north to south along the coast, as the intensity of sea breeze decreases from north to south. Swell attenuation due to opposing winds (from NE) is observed along the Ratnagiri coast during NE monsoon. The growth of wind seas (from NE) towards offshore and their modification by opposing swells (from SW/SSW) significantly contributed to the reduction in wave heights at shallow water depths off Dwarka. The role of opposing winds in the attenuation of swells along the west coast of India during NE monsoon season is significant. Numerical simulations were carried out to study the wave transformation between the depths 100, 50, 20, 10 and 5 m off Mumbai, Goa and Kochi. Diurnal variation is evident during the pre-monsoon season, and the magnitude of variation decreases from north to south.

First record of the marbled electric ray, Torpedo sinuspersici off Gujarat, north-west coast of India

One female specimen of Torpedo sinuspersici was collected from the trawl catch along the Saurashtra coast of Junagadh district, Gujarat, India. Although a total 486 species of marine fish have been identified so far from the State, the present paper describes the first record of T. sinuspersici from the coast of Gujarat State of India.

Comparative assessment of antioxidant activity in three edible species of green seaweed, Enteromorpha from Okha, Northwest coast of India

Abstract Three edible species of green seaweed Enteromorpha (E. compressa, E. linza and E. tubulosa) were studied for their antioxidant activity. The maximum total phenol content (%) was observed in the extract of acetone (11.63 ± 0.39), methanol (3.45 ± 0.18) and acetone (6.30 ± 0.06) for E.compressa, E.linza and E.tubulosa respectively. The excellent DPPH radical scavenging was observed in methanolic extract of E. compressa (IC50 1.89 mg/ml). The acetone extract of E. tubulosa showed good reducing power as compared to the extract of E. compressa and E. linza at 0.1 mg/ml. Methanol and propanol extracts of E. compressa showed good ferrous ion chelation activity. The extract of these three seaweeds exhibited high antioxidant activity in linoleic acid system during the incubation time. The potential of these extracts of Enteromorpha was evident, as it possessed various antioxidant activities. Hence, these extracts could be used as either natural antioxidants or ingredients in pharmaceutical industries. Industrial Relevance The results showed that different solvent extracts obtained from edible species of Enteromorpha exhibited good antioxidant activities. Bioactive compounds found in Enteromorpha species anticipate a major breakthrough for a variety of food/medical applications as they have the potential for application of such compounds as natural antioxidants in different food/pharmaceutical products.

Response of west Indian coastal regions and Kavaratti lagoon to the November-2009 tropical cyclone Phyan

Response of the coastal regions of eastern Arabian Sea (AS) and Kavaratti Island lagoon in the AS to the tropical cyclonic storm `Phyan’, which developed in winter in the south-eastern AS and swept northward along the eastern AS during 9–12 November 2009 until its landfall at the northwest coast of India, is examined based on in situ and satellite-derived measurements. Wind was predominantly south/south-westerly and the maximum wind speed (U10) of ~16 m/s occurred at Kavaratti Island region followed by ~8 m/s at Dwarka (Gujarat) and ~7 m/s at Diu (located south of Dwarka) as well as two southwest Indian coastal locations (Mangalore and Malpe). All other west Indian coastal sites recorded maximum wind speed of ~5–6 m/s. Gust factor (i.e., gust-to-speed ratio) during peak storm event was highly variable with respect to topography, with steep hilly stations (Karwar and Ratnagiri) and proximate thick and tall vegetation-rich site (Kochi) exhibiting large values (~6), whereas Island station (Kavaratti) exhibiting ~1 (indicating consistently steady wind). Rainfall in association with Phyan was temporally scattered, with the highest 24-h accumulated precipitation (~60 mm) at Karwar and ~45 mm at several other west Indian coastal sites. Impact of Phyan on the west Indian coastal regions was manifested in terms of intensified significant waves (~2.2 m at Karwar and Panaji), sea surface cooling (~5°C at Calicut), and moderate surge (~50 cm at Verem, Goa). The surface waves were south-westerly and the peak wave period (T p) shortened from ~10–17 s to ~5–10 s during Phyan, indicating their transition from the long-period `swell’ to the short-period `sea’. Reduction in the spread of the mean wave period (T z) from ~5–10 s to a steady period of ~6 s was another manifestation of the influence of the cyclone on the surface wave field. Several factors such as (1) water piling-up at the coast supported by south/south-westerly wind and seaward flow of the excess water in the rivers due to heavy rains, (2) reduction of piling-up at the coast, supported by the upstream penetration of seawater into the rivers, and (3) possible interaction of upstream flow with river run-off, together resulted in the observed moderate surge at the west Indian coast. Despite the intense wind forcing, Kavaratti Island lagoon experienced insignificantly weak surge (~7 cm) because of lack of river influx and absence of a sufficiently large land boundary required for the generation and sustenance of wave/wind-driven water mass piling-up at the land–sea interface.

Forest structure of arid zone mangroves in relation to their physical and chemical environment in the western Gulf of Kachchh, Gujarat, Northwest coast of India

To understand natural and anthropic control of mangrove vegetation in the Gulf of Kachchh, a study was undertaken of its vegetation structure. Over 2 years (1999–2000) at three sites, mangrove vegetation was studied, including tree density, tree height, tree girth at breast height (GBH), canopy index, regeneration class and recruitment class, together with physico-chemical characteristics of water and sediment and the textural aspects of sediments. Reflecting the hot, arid hinterland of Gujarat, ambient temperatures and salinities are high in this macrotidal estuary, decreasing somewhat during the monsoon. The littoral soil supporting the mangrove is abundant in silty loam, silty clay and slity clay loam. The density of mature trees (Mangrove plants of GBH > 25 cm) ranged from 2088/ha to 3011/ha, the height of the trees ranged from 1.42 m to 9 m and the maximum mean GBH at all three sites was 33 cm, and the mean canopy indices ranged between 4.77 m2 and 10.45 m2. The maximum density of regeneration stages was 100,800/ha while that of recruitment stages was only 3,040/ha. While quite severely impacted by anthropic exploitation at one site, the mangrove ecosystem of Gulf of Kachchh was found to be mainly healthy and supporting associated organisms. The ecological and social role of the mangrove, and the potential for its future conservation are briefly discussed in the light of current legislation.

Fishery resources in arid zone mangroves in gulf of Kachchh, Gujarat, northwest coast of India

The finfish and shellfish resources were assessed quantitatively and qualitatively in regard to their abundance in creek waters at three sites within a period of two years, from January 1999 to December 2000, in the western mangrove areas of Kachchh. The catch rate varied from 0.69 to 6.99 kg•h^(-1). It was low during monsoon (July to October), which could be due to the freshwater-flow-induced salinity reduction in all the sites. Among 38 species recorded, 5 were shellfish and 33 were finfish. The spawning period of fishes was found to be during summer and early monsoon period (May to August). Surface water temperatures varied from 17℃ to 37℃. Sa-linity values varied from 34 to 44 and the pH ranged between 7 and 8.9. Variation in dissolved oxygen content was from 3.42 to 5.85 Ml•L^(-1). The high fishery densities in these semi arid mangrove creek areas were recorded during monsoon and early winter season.

Seasonal variation in biomass and species composition of seaweeds stranded along Port Okha, northwest coast of India

Port Okha coast, which is known for its luxuriant growth of a diverse assemblage of seaweeds on Saurashtra coast, is found to have abundant quantities of seaweeds being drifted and washed ashore every year. Studies conducted for quantifying the stranded seaweeds from May 2004 to April 2005 showed an average biomass value of 3.10 kg fresh wt/m2/month with maximum being 6.60 kg fresh wt/m2 in April. The stranded weeds constituted a total of 62 species during the entire study period. Of this, Rhodophyta ranked high with 26 species followed by Chlorophyta with 22 species and Phaeophyta with 14 species. The stranded seaweeds that were washed ashore provide valuable floristic information about the intertidal and near shore sub-tidal algae of the respective regions. Although natural senescence of seaweeds is one of the major factors, strong currents primarily forced by tides, also contribute to the uprooting and subsequent drifting of seaweeds on to the beach. This ultimately causes changes in floristic features of the existing algal beds.

Infaunal Macrobenthic Community of Soft Bottom Sediment in a Tropical Shelf

Abstract Studies of benthic communities in tropical shelf waters are limited. In this study, we deal with the infaunal benthic community of soft bottom sediment of the tropical eastern Arabian Sea shelf. Benthic macroinfauna was sampled with a Smith–McIntyre grab at 30 stations on the continental shelf of the eastern Arabian Sea (northwest coast of India) during January–February (premonsoon) and November (postmonsoon) 2003 from 30 to 200 m depth. The faunal composition, abundance, and diversity of species together with environmental parameters are reported. The sites were clustered into “associations” on the basis mainly of sediment texture and depth. Mean benthic abundance was high in the shallow and intermediate depths and decreased toward deeper areas. Diversity increased with depths up to 100 m during both seasons and decreased beyond 100 m depth. The dominant benthic group was Polychaeta during both seasons. Species richness and diversity were higher during premonsoon compared with postmonsoon. Shall...

Feasibility of cultivation of Kappaphycus alvarezii (Doty) Doty at different localities on the Northwest coast of India

Kappaphycus alvarezii was cultivated at three places, viz. Mithapur, Okha and Beyt Dwarka on the Northwest coast of India. The biomass and growth rates were measured at 15-day intervals up to 45 days and varied differently for different growth periods at these places. Thus, at 15, 30 and 45 days, the biomass (fresh wt) varied from 182.0±19.96 to 435.0±23.66 g, from 366.0±118.09 to 1096.0±61.43 g and from 530.5±50.95 to 1537.0±43.54 g, respectively, with respective daily growth rates (%) from 3.95±0.78 to 9.80±0.63, from 3.64±0.01 to 13.98±3.07 and from 3.69±0.23 to 6.07±0.06. The seawater temperature, salinity, nitrate and phosphate ranged from 19.3 to 26.9 °C, from 30.81 to 36.83‰, from 11.60 to 19.75 μmol L−1 and from 2.37 to 5.0 μmol L−1 respectively. The growth rate between the culture months was significantly different at Okha at P<0.01. Further, it was significantly correlated to salinity at Mithapur while at Okha and Beyt Dwarka, the same was significantly correlated to nitrate and seawater temperature. Based on this study, commercial cultivation at these localities is quite feasible.

Oil Spill Sensitivity Analysis and Risk Assessment for Gulf of Kachchh, India, using Integrated Modeling

Abstract Oil-related activities such as single point mooring (SPM), installation, navigation, marine transportation, and oil exploration all have the potential to cause oil spills and pose major threats to the coastal ecosystem along the Indian coast. The Gulf of Kachchh, a biologically rich ecosystem composed of mudflats, submergible shoals, islands, sandy beaches, rocky shore, coral reefs, and mangroves, is located along the northwest coast of India. Its proximity to the Persian Gulf has attracted the establishment of facilities for transferring, piping, and loading of crude oil and petroleum products, mainly the Arabian crude. The marine ecosystem of the gulf is always at risk due to accidental and operational oil spills in the gulf. In this paper, an attempt is made to identify the resources that are at risk due to such oil spills. An integrated numerical simulation modeling approach has been applied to generate the probable oil trajectory and fate analysis, and the results have been integrated into g...

Four new species of the genus Rhopalophthalmus (Mysidacea: Crustacea) from the northwest coast of India

Four species belonging to the genus Rhopalophthalmus—R. mumbayensis, R. anishi, R. murudana, and R. vijayai—are described as new to science. All four species are distinguishable from each other and from other related species by the combination of characters afforded by the number of spines on the antennal sympod, number of carpopropodal segments of the thoracic endopods, relative length of the vestigial endopod of the eighth thoracic limb, number of lateral spines on the telson, and the relative length of the distal spines.

Prospect hunting below Deccan basalt: imaging challenges and solutions

Thick Mesozoic sediments under the basalt cover of the Deccan traps along the northwest coast of India are considered to be potential targets for hydrocarbon exploration together with the Indus basin of Pakistan. Sub-basalt seismic imaging is difficult in these formations, as the Deccan traps are composed of multilayered lava flows. Seismic imaging issues associated with high velocity basalt include: 1. Multiples generated in interbedded units of basalt and between the top of the basalt and the sea floor. 2. Energy scattering from and absorption by heterogeneities. 3. Wave mode conversion at the top of the basalt. Radon-based analysis can solve some of the difficulties related to multiples. The use of low frequency sources and multicomponent technology are other methods commonly suggested to improve sub-basalt imaging. The Deccan basalt area is very heterogeneous and has not been mapped effectively by high resolution seismic. At present, only standard streamer data are available in this area. Model-based imaging together with other methods can improve the sub-basalt image and add confidence in the reservoir modelling. Imaging challenges in this setting are discussed using examples from the Kutch basin on the northwest coast of India, where the primary reservoir (Bhuj formation) is overlain by thick basalt.

A finite element simulation of tidal circulation in the Gulf of Kutch, India

A finite element (fe) model using the software package adcirc was developed to simulate the tides and currents in the Gulf of Kutch, located on the northwest coast of India. The surface elevations from the model were analysed for the amplitudes and phases of four major tidal constituents (M 2, S 2, K 1 and O 1) and the principal overtide (M 4) and compared with observed values. Model currents were compared with observations at three locations along with the corresponding results from a finite difference model for the same region. The results were found to be consistent, with the fe model providing improved resolution in key areas. Residual circulation evaluated by forcing the fe model with M 2 tide and winds (those typical of the southwest monsoon) show currents, which are directed upstream in the shallow region of the Gulf. A better simulation of lateral variations in currents in the fe model helps in identifying relative differences in tidal circulation and residual circulation between the deep and shallow regions of the gulf.

New species of Pseudodiaptomus (Copepoda:Calanoida) from the salt pans of the Gulf of Kutch, India and a comment on its speciation

A new species of calanoid copepod Pseudodiaptomus pankajus (family Pseudodiaptomidae) is described from the north-west coast of India. This species inhabits high saline waters of salt pans. It appears to have evolved allopatrically during the Cretaceous as a result of continental drift.