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Analytical validation of a modified turbidimetric assay to screen sulphur oxidizing bacteria

Conventional turbidimetric assay for sulphate determination was modified to 100 times lesser reaction volume on a convenient format using microtitre plate based platform, targeting routine microbiological applications to screen sulphur oxidizing bacteria (SOB) cultures. The modified assay was linear up to 1500 mg/L of sulphate concentration, which is about 37.5 times more than that of conventional assay. Upon regression analysis, linear equation y = 1.243× + 0.011 was obtained having R2 value of 0.998. The modified assay was fully validated in terms of precision, limit of detection (LOD), limit of quantification (LOQ), sensitivity, selectivity and robustness to assure the reliability during final applications. LOD and LOQ were found as 7.4 mg/L and 24.8 mg/L of sulphate concentration respectively. Further, accuracy of the assay over routine SOB screening media components was tested, and proved as reliable and suitable for the intended application.

Demand pattern and willingness to pay for high value fish consumption: Case study from coastal cities in Kerala

Fishing occupies an important place in the economy of Kerala State, south India as a vital source of food and protein, avenue for employment and most importantly in the export market. Kerala’s population is basically a fish eating population where the level of fish consumption is four times the national average. The annual per capita fish consumption has increased from 15 kg in 1970s to about 23 kg in 2011. The high value fishes like shrimps, squids, seerfishes and pomfrets are massively exported due to economies of scale, thereby leading to limited local availability resulting in high domestic prices. The present study assessed the fish intake pattern across 600 middle income consumer households of urban area in the metropolitan cities of Thiruvananthapuram, Kochi and Kozhikode in Kerala. The average family size was found to be 4.2. The study concentrated on income cum expenditure pattern, buying trend, hindrances in fish consumption and readiness to pay for high value fishes. Willingness to pay was figured out using logit model. The results indicated that the income and access to the selling points of fish enhanced the demand. The per capita montly fsh consumption was found to be 2.2 kg with low value per capita fish consumption estimated at 1.43 kg and average high value per capita fish consumption at 0.77 kg across study areas. The fish food consumption pattern trends across the different study locales clearly portrayed that there exists significant demand for high value fish and fish products. Most local consumers weren’t aware about low export price and more than 50% expressed their willingness to pay which indicated existence of a high consumer surplus. Resutls of the study stressed the need for governmental intervention in controlling fish exports thereby safeguarding local fish food security, replacing exports with local marketing; considering the demand for sizeable quantum and ample readiness to pay.

Biometry, length-weight and length-length relationships of flathead sillago Sillaginopsis panijus

Biometry, length-weight relationships (LWRs) and length-length relationships (LLRs) of Sillaginopsis panijus (Hamilton, 1822) were investigated in the Indian coast of north-western Bay of Bengal. Altogether 622 specimens were collected between August 2018 and September 2019 from landings by trawls (30-35 mm mesh size), gillnets (15-55 mm mesh size) and shore seines (7-15 mm bag mesh size). The total length and weight of the specimens ranged from 7.8-40.3 cm and 2.9-506 g, respectively. The LWR established was W=0.0048 L3.059 for males, W=0.0032 L3.185 for females and W=0.0047 L3.0645 for indeterminates, indicating positive allometric growth pattern. All the LWRs were highly significant (p<0.001, r2?0.977). The highest coefficient of correlation (r) was observed for total length against fork length (0.999) and lowest for head length against eye diameter (0.951). The fin formula was expressed as D1 X, D2 I + 24-28, P 17-22, V I + 5, A II + 25-27, GR 2-3/6-9. The study provides the first detailed account of the biometric relationships of S. panijus in the north-western Bay of Bengal, which can be used as baseline information for subsequent biological and population based studies in the region.

Misidentification and notes on Plesionika semilaevis, Spence Bate,1888 from the southern coast of India

The commercial deep-sea caridean shrimp Plesionika martia (Milne-Edwards 1883) has long been recorded from India and constitutes an important species of deep-sea shrimp catches in the southern coast of India. However, the present study revealed that all the previous records of “Plesionika martia” is actually a misidentification of the closely related species P. semilaevis, which was recently obtained from Indian waters. The specimens were collected from three fish landing harbours (Sakthikulangara, Kalamuku, and Tuticorin) fished from the depth of about 150–250 m along the southern coast of India during 2014 to 2017. The level of interspecies genetic divergence between 16S rDNA (16.8– 18.6%) and COI (26.1%) sequences of the Indian P. semilaevis and P. martia sequence retrieved from NCBI were found to be comparatively high. The current work illustrates the detailed morphological characters with color photographs of the species, P. semilaevis off the Indian Exclusive Economic Zone (EEZ).

First distributional report of Filinia camasecla Myers, 1938 from peninsular India

This work reports the first distributional record of Filinia camasecla Myers, 1938 in south India from the Cochin backwaters on the northern stretch of Lake Vembanad. Earlier, the distribution of this species has been known from Oriental (South East-Asia) and Neotropical biogeographical realms. Though it comes under the oriental endemics no previous records of this species were available from this area or other parts of Vembanad backwaters. The occurrence of F. camasecla in this additional geographic region highlights the range extension of the species.

Redescription and molecular characterization of Crenidens macracanthus Gunther, 1874

Crenidens macracanthus was originally described in 1874 based on a single specimen collected from Chennai (Madras), south-east coast of India. In 1875, the species was synonymized with C. indicus without citing any valid reason. Since then, no taxonomic studies have been attempted for the genus Crenidens, except in 2013 the species was resurrected from synonymy and redescribed as a valid species based on the holotype and non-type specimen. In view of the fact that C. macracanthus is a poorly known species, it is redescribed based on examination of 30 additional specimens of 105.8–162.2mm SL, collected from Puri, Odisha, north-east coast of India (Bay of Bengal) from 2017–2019, using morphological and molecular examinations. Our study provides a detailed morphological description, first colour photographs and phylogenetic analysis using COI barcodes of the species. The study has expanded the range in several morpho-meristic characters in comparison with the type and non-type specimens described earlier. The species in fresh condition can be easily distinguished from its two congeners (C. crenidens and C. indicus) by the yellowish tip of the lower caudal-fin lobe. Our study has also extended the distribution range of C. indicus (previously known only from the north-eastern Arabian Sea) to the eastern Indian Ocean, based on examination of a preserved specimen collected from Tuticorin, Tamil Nadu.