Ratnagiri Coast Research Articles

Occurrence of Oxyurichthys paulae (Pezold, 1998) from Ratnagiri Coast, Maharashtra, India

Oxyurichthys paulae (Jester goby) was originally described from the Western Indian Ocean, known only from Cochin, India. Based on the specimens with a maximum SL of 69 mm, the occurrence of O. paulae from the Ratnagiri Coast in Maharashtra, India was reported in this paper. A specimen was collected from a bottom trawler that operated off the Ratnagiri coast of Maharashtra and landed at Mirkarwada fishing harbour in Ratnagiri, Maharashtra, on May 2024, for the first time. The fish was taxonomically identified as O. paulae [1], belonging to the family Oxudercidae based on its morphometric and meristic characteristics. The result of the current study confirmed the occurrence of this species from the eastern Arabian Sea and provided the first report of this species from Ratnagiri, Maharashtra.

Reproductive biology of green crab Scylla tranquebarica (Fabricius, 1897) found in Ratnagiri Coast, Maharashtra, India

Reproductive biology of green crab Scylla tranquebarica (Fabricius, 1897) found in Ratnagiri Coast, Maharashtra, India

Preliminary observation on the stock of Jinga shrimp, Metapenaeus affinis (H. Milne Edwards, 1837) along the Ratnagiri coast of Maharashtra, India

Preliminary observation on the stock of Jinga shrimp, Metapenaeus affinis (H. Milne Edwards, 1837) along the Ratnagiri coast of Maharashtra, India

Diet composition and reproductive biology of spineless cuttlefish Sepiella inermis (Orbigny, 1848) from Ratnagiri (Arabian Sea, North-west coast of India)

In the present study, we investigated some biological aspects of the spineless cuttlefish,Sepiella inermis (Orbigny, 1848) along the Ratnagiri coast of Maharashtra, India. A study ondiet composition and reproductive biology of the species was carried out. Dorsal mantlelength (DML) ranged from 35.9 to 93.3 mm for males and 29.3 to 98 mm for females.Feeding intensity was noted to be low during most of the study period. S. inermis was foundto have a protracted spawning season. The overall male: female ratio was 1:1.02 during thestudy period. The average fecundity was found to be 358 eggs. Length at sexual maturitywas estimated to be 42 mm and 53 mm for males and females respectively. The informationobtained from the study will help the fishery agencies to formulate management measuresin sustaining the landings of S. inermis in the region. Keywords:Biological studies, Cephalopods, Maharashtra,Ratnagiri coast, Sepiella inermis, Spinelesscuttlefish

Biology of the cleftbelly trevally Atropus atropos (Bloch and Schneider, 1801) from Ratnagiri coast of India

The cleftbelly trevally Atropus atropos (Bloch and Schneider, 1801) is one of the important carangid species landed mostly as trawl bycatch along Ratnagiri coast. Investigations were carried out on A. atropos with respect to length-weight relationship, condition factor, morphometrics, feeding and reproductive biology. The length-weight relationship indicated negative allometric growth in A. atropos. Morphometric measurements showed significant correlation with total length. The gut content analysis revealed A. atropos to be a carnivore fish feeding mainly on Acetes spp., small teleostean fishes, cephalopods, and squilla. Sex ratio showed dominance of males. Gonadosomatic index and maturity studies indicated that A. atropos has a protracted spawning season extending from May to December. Length at sexual maturity for females was estimated to be 171 mm. Fecundity ranged from 16458 to 138688 eggs with an average of 70097 eggs. Ova diameter studies showed that A. atropos spawns twice in a protracted spawning season. Keywords: By-catch, Carangidae, Carnivore, Reproductive biology, Spawning season

Comparative footprint studies of single and multiday trawl fishing along Ratnagiri coast, Maharashtra, India

Trawl fishing is widely recognised as the most productive and industrious fishing method in the world. Due to the importance of trawl fisheries along the Ratnagiri coast of Maharashtra, the present comparative study was undertaken on single and multiday trawl fishing in the region. In this study, monthly variations in fishing depth, catch per hour (CPH), discard per hour (DPH), spatio-temporal species distribution and spatial prediction of catch-discard of 136 trawl hauls were analysed. Single and multiday trawlers were operated from 15°53’24’’N to 18°00’36’’N latitude and 72°55’55’’E to 73°25’48’’E longitude within a depth range of 10 to 64 m in the Arabian Sea. For the multiday trawlers, maximum CPH of 68.30 kg h-1 was recorded in October 2015, while single day trawlers recorded CPH of 42.70 kg h-1 in November 2015. Average DPH for multiday and single day trawlers were recorded as 7.66 and 3.84 kg h-1 respectively. The study found that CPH and DPH were significantly (p<0.05) higher in multiday trawlers than single day trawlers. Based on spatial mapping, high fishing pressure was observed in the area south-west off Ratnagiri. Our results highlighted the need for suitable strategies for conservation and management of fisheries resources to achieve long-term sustainability in the region. Keywords: Catch, Discard, Diversity, GIS mapping

Study of karyotypes of green chromid, Etroplus suratensis (Bloch, 1970) from Ratnagiri coast, Maharashtra, India

Study of karyotypes of green chromid, Etroplus suratensis (Bloch, 1970) from Ratnagiri coast, Maharashtra, India

Seasonal changes in feeding habit of Johnius elongatus (Mohan, 1976) Sciaenid species from Ratnagiri coast, Maharashtra, India

Seasonal changes in feeding habit of Johnius elongatus (Mohan, 1976) Sciaenid species from Ratnagiri coast, Maharashtra, India

Antifungal and antibacterial activity of marine sponges from Ratnagiri coast of India.

Marine sponges have proved to be a rich source of bioactive metabolites with multiple pharmacological properties. In this study, we have investigated the antifungal and antibacterial activities of methanol extracts of Cliona, Haliclona cratera, Hyrtios cavernosus, Spongia obscura, Sarcotragus foetidus, and Xestospongia carbonaria and fractions from X. carbonaria S. obscura and H. cratera. The antibacterial activity was determined by agar disc diffusion method against clinical gram-positive- Staphylococcus aureus, Bacillus subtilis and gram negative- Escherichia coli, Pseudomonas aeruginosa bacteria. The antifungal activity of the extracts and fractions was determined against Candida albicans and Aspergillus niger. S. obscura, X. carbonaria, H. cavernosus, and H. cratera exhibited good antibacterial activity against the tested gram-positive bacteria with larger zones of inhibition at 19±6 mm, 19.5±5.5mm, 20±0 mm and 23±0 mm. S. foetidus gave good inhibition of gram-negative bacteria at 19±0 mm. They showed moderate antifungal activities against C. albicans and A. niger. Cliona, H. cratera and H. cavernosus gave inhibition with 20±5 mm, 15.5±0.5 mm and 25.5±14.5 mm for A. niger. The MIC for Xc_PE_2, Sob_n but_1 and Hc_n but_3 was determined. H. cavernosus, S. foetidus, S. obscura and X. carbonaria showed presence of fatty acids and sterol type of compounds. The mass of molecular ions in purified fractions helped in characterization of known compounds in H. cratera, X. carbonaria and S. obscura which exhibited good antimicrobial activity.

Coastal Vulnerability Assessment: A case study of the Ratnagiri coast, Maharashtra, India

The coastal zone is a vulnerable habitat that needs extra caution to protect ecosystems. Coastal systems are increasingly threatened by possible climate change consequences, as evidenced by the Intergovernmental Panel on Climate Change’s consecutive assessments. Increased tropical storm occurrences in recent years, in addition to the devastation caused by the tsunami in December 2004, have highlighted the necessity of analyzing the coast’s susceptibility to flooding-induced hazards to get a better knowledge of the factors that generate various hazards and, as a result, reduce the after-effects of future occurrences. The Ratnagiri coast in Maharashtra is prone to erosional hazards, periodic land rehabilitation, and sudden rises in sea level. The main objective is to calculate the CVI (Coastal Vulnerability Index) for the Ratnagiri coast. To analyze the vulnerability of the coastal region, eight risk parameters were used, viz. shoreline change rate, coastal elevation, sea level change rate, coastal slope, tide range, significant wave height, coastal geomorphology, and tsunami arrival height. The coastal vulnerability map was created by categorizing the numerous coastal portions into three vulnerability groups: high, medium, and low, which will aid coastal residents in risk mitigation in the future.

Design and General Characteristics of ‘Disco Dol’ (Two Seam Trawl) Operated along Ratnagiri, Maharashtra

The present investigation was taken to know the variations with respect to design, net specification, mesh size of Disco dol trawl net operated along the Ratnagiri coast. A total of 42 trawl net was sampled physically by using measurement tape and scale. The data were collected by structured schedule consisting of two major sections. The first section was for vessel details and second for the specifications of trawl nets. The study revealed that, two seam locally known ‘Disco dol’, operated from Ratnagiri was observed with eight belly sections of overall length ranges from 41 to 52m. Wings of the net were triangular in shape with a mesh size variation between 120-440 mm. The dimensions such as breadth, number of meshes along breadth and mesh size were decreasing from first to last belly section, but average number of meshes per metre were increasing from first to last belly. Wide reduction of 400-40 mm was observed in mesh sizes of belly section for Disco dol from first to last belly. Cod end mesh size of trawl operated from Jaigad, Kasarveli, Mirkarwada and Purnagad landing centres was recorded as 20 mm. In Ratnagiri, two seam trawl net was used mainly to catch fishes.

Length-weight relationship study of mangrove clam Geloina proxima (Prime-1864) of Dapoli Coast of Ratnagiri District

Mangrove clam Geloina proxima is one of the dominant indigenous bivalves of Ratnagiri Coast. The study of Length-weight relationship of clam G. proxima was carried out during July 2017 to June 2018 to understand growth rate and its pattern. Average total length for males and females recorded was 65.40 mm and 65.25 mm, respectively, which is also supported by the calculation of the weight studies. It is interesting to note that in G. proxima, irrespective of the sex, there is a coordination between the length and weight relationship. In the present study significant difference was observed between the length-weight relationship to weight relationship of male and females of G. proxima. Analysis of results for length-weight relationship in G. proxima indicates negative allometric growth pattern. It is observed that weight of G. proxima bears a curvilinear relationship with the length that becomes linear on logarithmic transformation. The value of correlation coefficient in males was r = 0.97 while the same in females were r =0.98, which were found to be statistically highly significant. The coefficient of determination r2 is an indication of goodness of fit of regression to the observed data. The closer it is to 1, the better is the fit.

Studies on gonad index and fecundity of mangrove clam, Polymesoda erosa (Solander, 1786) of Ratnagiri coast

Gonadal maturation studies were carried out on one of the largest growing tropical mangrove clam species, Polymesoda erosa from Ratnagiri coast of Maharashtra. Gonadal maturation studies under laboratory conditions were also carried out to assess the effect of temperature and salinity on Gonad Index (GI) in two separate experiments each of 60 days duration. The optimum temperature and salinity observed for GI was 30 °C and 25 ppt, respectively for both the sexes. Estimated fecundity of P. erosa within the range of 40 to 120 mm shell lengths was studied. It was observed that maximum numbers of matured oocytes were 1773893 whereas minimum number was 384227.

Effect of salinity and temperature on broodstock conditioning of mangrove clam Polymesoda erosa (Solander, 1786)

Culture of molluscan is clearly limited by the availability of seed, as this production proceeds almost exclusively from natural recruitment. Artificial spawning and larval rearing programs could provide an alternative source of spat. This study was designed to evaluate the effect of different conditioning temperature and salinity on the broodstock maturation and Condition Factor of mangrove clam (P. erosa) collected from different locations of Ratnagiri coast. Batches of clams from different sites were collected in February, and conditioned at temperature 26 °C, 28 °C, 30 °C and 32 °C. For conditioning at different salinity, it was kept at 10,15,20,25,30 and 35 psu, The results showed that the oocyte maturation was faster at salinity 35 psu and the best conditioning temperature was 32 °C. The Condition Factor (CF) was higher at 32 °C temperature and at 30 psu salinity, whereas, no significant difference was observed in CF at 30 and 35 psu. These results suggest that the efficient conditioning temperature and salinity is related to the natural spawning season.

Vulnerability Assessment of the Ratnagiri Coast (Maharashtra, West Coast of India)

Vulnerability Assessment of the Ratnagiri Coast (Maharashtra, West Coast of India)

Biometric analysis of moustached thryssa Thryssa mystax (Bloch and Schneider, 1801) along the Ratnagiri coast of Maharashtra, India

The moustached thryssa Thryssa mystax (Bloch and Schneider, 1801), is an important bycatch landed by trawl nets and mini purse seines at Ratnagiri in Maharashtra. Morphometric characters and length-weight relationship of the moustached thryssa were studied from 876 specimens comprising of 436 males, 407 females and 33 indeterminates, collected from Ratnagiri. The coefficient of correlation of total length against other morphometric characters of T. mystax ranged between 0.3967 (against pre-pelvic length) to 0.9966 (against fork length). All morphometric measures had a high and moderate degree of correlation with total length. The length-weight relationship indicated isometric growth. The coefficient of correlation (r) for the length-weight relationship was estimated at 0.9327, 0.9266, 0.9743 and 0.9379 for the males, females, indeterminants and pooled data, respectively.

Bivalve Fishery of Sindhudurg and Ratnagiri Coast, Maharashtra, India

Bhendekar, S.N.; Mhatre, V.D.; Sasikumar, G.; Mohamed, K.S., and Chellappan, A., 2019. Bivalve fishery of Sindhudurg and Ratnagiri coast, Maharashtra, India. In: Jithendran, K.P.; Saraswathy, R.; Balasubramanian, C.P.; Kumaraguru Vasagam, K.P.; Jayasankar, V.; Raghavan, R.; Alavandi, S.V., and Vijayan, K.K. (eds.), BRAQCON 2019: World Brackishwater Aquaculture Conference. Journal of Coastal Research, Special Issue No. 86, pp. 255–257. Coconut Creek (Florida), ISSN 0749-0208.Estimated bivalve landing of Maharashtra was 1,237 t in 2017. Oysters dominated the fishery (79%) followed by clams (17%) and mussel (4%). The Indian rock oyster, Saccostrea cucullata locally known as ‘Kalva’ contributed 90% to the oyster catch. The fishery was observed mainly in Sindhudurg and Ratnagiri Districts. Clam landing comprised of Meretrix meretrix (44%), M. casta (30%), Paphia malabarica (18%), Katelysia opima (7%) and Polymedosa erosa (1%). Green mussels (Perna viridis) were harvested along the coastal waters of Ratnagiri. Meretrix meretrix showed dominance in all month followed by M. casta and P. malabarica. Catch per unit efforts for clams and oyster were highest during June and July month. There was good demand for bivalves in local markets during the mechanised fishing ban period. Mostly women were handpicking the clams during low tide. There was good demand for bivalves in local markets during the mechanised fishing ban period (June-July). The correlation matrix shows condition index and percentage edibility correlated with the water temperature in the creek.

Effect of Temperature on Cytological Alterations in Gonads of Estuarine Bivalves at Bhatye Estuary, Ratnagiri Coast

Effect of Temperature on Cytological Alterations in Gonads of Estuarine Bivalves at Bhatye Estuary, Ratnagiri Coast

Population characters of silverbelly Photopectoralis bindus (Valenciennes, 1835) along the Ratnagiri coast of India

Population characters of silverbelly Photopectoralis bindus (Valenciennes, 1835) along the Ratnagiri coast of India

Intertidal Macrofaunal Invertebrates Diversity from Ratnagiri Coast, (MS) India of Arabian Sea

Intertidal Macrofaunal Invertebrates Diversity from Ratnagiri Coast, (MS) India of Arabian Sea