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Variations of chlorophyll-a (chl-a), sea surface temperature (SST) and net primary productivity (NPP) along with fish catch were studied along the coastal waters off Karnataka, west coast of India from January 2007 to December 2016. These variations are linked with the Indian Ocean Dipole and El Nino/Southern Oscillation—Nino3.4 SST index. NPP was estimated by using vertically generalized production model. Change in NPP values over the decade (2007–2016) was studied in context of global reports of decline in productivity over the period. It is very important to understand the pattern of NPP variability as well the interrelationship with SST over a long period to study its impact on distribution of the fishery resources. Trend showed that there is reduction in productivity after 2012 and this trend continued in subsequent years. During the study period, an increasing trend in SST is observed along the Karnataka coast. The present study shows that a strong El Nino event was seen in 2015, along with declined productivity in the coastal waters off Karnataka by ~ 24% and increase in SST by ~ 1% from the average of 10 years (2007–2016). Increased SST and low ocean productivity resulted in reduced fish catch with the decline of 6.7% in total fish catch along the Karnataka coast from 2014 to 2015. In 2016, 5.29 lakh tones of fish catch, was estimated resulting in 19.6%, increase compared to 2015. During southwest monsoon, sea surface height anomalies (SSHa) showed negative anomaly trend and increased Ekman pumping resulted in upwelling over the study area.

This is CMLRE contribution no. 158.-- 14 pages, 7 figures 5 tables.-- Data availability statement: Data will be available on personal request to the corresponding author, Morphology of the fish and otoliths are popularly used in the discrimination of species/stocks/populations and also to gather meaningful conclusions about their ecology. This approach is useful to enhance our understanding of the relationship between form and function in fishes when a direct assessment is impossible. Inter-species variation was analysed using geometric morphometric analysis for fish body shape, while morphometry and wavelet functions for sagittae morphology. A clear ecomorphological pattern in the body, as well as otolith shape, is evident among species as deeper inhabiting species possess a deeper body with oblong otoliths compared with shallower species that possess a more streamlined body with fusiform otoliths. We also observed that deeper species (P. obscura) possess bigger eyes for the optimum use of available light and bigger otoliths with higher otolith sensory area and otolith area ratio (S:O) for better sound reception capacities. Our hypothesis supports that the differences in fish morphological as well as sensorial traits (otoliths), which are closely related to their locomotion, foraging pattern and depth of habitation, lead to trophic segregation which in turn encourages their coexistence. This is the first work that discusses the relationship between body shape, otolith morphometry and morphology in deep-sea fishes and their ecomorphological interpretations, The financial, technical and logistical support from CMLRE is thankfully acknowledged, With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)

Mobility of labour across the country continues as a major source of labour supply in ensuring economic development across all sectors including the primary sector. The migrant labour in search of better employment emancipates better living conditions through meaningful employment and better financial status. The coastal states of Maharashtra with commendable marine fish landings provides states with commendable marine fish landings provide ample opportunities for migrant fishing labour across the year. The migrant labors are involved in harvest and post harvest operations. The present study tries to assess the major factors leading to labour migration and its effect in the state of Karnataka state. About 100 respondents were met for a primary survey and result reveals that the migration leads to the increase in savings. Majority (57 percent) of the respondents were youth (Below 30). Most respondents completed high school levels of education. The respondents migrated from 5 different states with majority from Jharkhand (36%), Assam (23%) and Orissa (13%) to Mangalore district in Karnataka and the 54 percent respondents migrated in the year 2000. Garrett ranking method assessed the main reason and problems of migration and also used to find the effect of migration on socioeconomic status. The main reason for migration is the low income and the major difficulty during migration was the difficulty in language. The major achievement of the migrant labour had been the quality education provided to their children.

The spatial and seasonal variability in finfish availability in the tropical Kali Estuary, in Karwar was studied from January 2017- May 2019 at three stations. A total of 26 species belonging to 9 orders and 20 families were recorded from the Kali Estuary and the order Perciformes with 16 species dominated the group (62%) followed by order Mugilliformes and Pleuronectiformes (8%). Maximum abundance was observed during the pre-monsoon season in all the stations. Excluding Ambassis ambassis which was abundant in all the stations, Caranx ignobilis dominated in all the stations. Truly marine and estuarine species of fishes recorded dominated than the freshwater estuarine ones like Etroplus suratensis, Scatophagus argus, Aplocheilus lineatus. Number of species recorded at each station during the study ranged from 11 to 25 and it was significantly different between stations. The Shannon- Wiener diversity index ranged from 2.0 to 4.6, the minimum in station 1 and maximum in station 3. The seasonal analysis of diversity also showed minimum value during the monsoon season in station 1 and maximum value in station 3. The minimum value (2.2) of Margalef richness index was also recorded in Station 1 during monsoon season and maximum value (4.2) in Station 2. When comparing the relative abundance using Pielou’s evenness index (J’) the values were in the range of 0.92 to 0.99 which was closer to one, indicating evenness in distribution. There was similarity in species composition according to different seasons except for monsoon season in Station 1. The same pattern was also evident in the MDS plot where seasonal aggregation was observed between the stations. In addition to the diversity studies, the surveys also threw light on the abundance and seasonality of candidate species suitable for mariculture like C. ignobilis, Lutjanus spp., Etroplus spp., etc. Judicious exploitation of the species could help brackishwater fish farmers.

Ten-year satellite derived data (January 2007 to December 2016) were used to investigate the variability of Chlorophyll-a (Chl-a), sea surface temperature (SST), net primary production (NPP) in the eastern Arabian Sea (AS). This study is aimed to show the coupling of physical and biological processes to understand how temporal, annual and inter-annual variations occur and the forcing mechanisms behind these variations in the ocean environments. This work is linked to Indian Ocean Dipole and the El Nino/Southern Oscillation, which frequently co-occur and drives inter-annual changes within the AS. Vertically Generalized Production Model was used to estimate NPP using chl-a, Photosynthetically Available Radiation, euphotic depth, and maximum photosynthetic rate from SST. The relationship between NPP and SST showed change in the pattern over the study period. The NPP in the AS is characterized by an unusual decline during El Nino events. AS is more productive during summer monsoon (June–September) due to coastal upwelling, wind driven mixing and lateral advection processes. There was decline in NPP after 2014 and this trend continued in the following years. The present investigation revealed that the strong El Nino condition was observed in 2015 and productivity of AS declined by ~ 19%, while SST increased by ~ 2% from an overall average of 2007–2016. Increased SST and low productivity could result in low fish catch in AS. Increasing trend in SST could be attributed to the extreme events like cyclones occurring along the west coast of India.

The present study reports observations of 13 giant freshwater whipray (Urogymnus polylepis) from commercial fish landings along the north-east coast of India and updates existing records based on field observations and local social media reports. The disc width of the landed specimens ranged from 120 to 223 cm and they weighed 95-300 kg. All 13 specimens observed were mature (nine females and four males) and three females were pregnant, with embryo numbers ranging between 4 and 15. Globally, U. polylepis is listed as 'Endangered', and greater protection measures are needed in India to assist in reversing current population declines.

Background: The fishes of the family Carangidae forms one of the largest families of bony fishes, representing about 140 species, widely distributed in all tropical and temperate marine waters of the world. In recent past, fishes of this family are exhibiting new geographical distribution which could be attributed to climatic variability. Methods: The specimens were collected from multiday trawl boats operated along Karnataka coast. Morphometric and meristic characteristics together with genetic analysis using DNA bar coding was used to validate the identity of the specimen. Spatial distribution map of the species in Indian Ocean was generated using the information from the present study and available literature. Result: The morphometric and meristic characteristics of the specimens of greater amberjack, Seriola dumerili collected during the study were comparable with the previous investigations. The phylogenetic tree constructed using sequences of COI (MW974826 and MW974827) of the Seriola species showed distinct clustering among species with significant bootstrap values confirming the identity to the extent of 99% with the sequences of Seriola dumerili deposited in NCBI GenBank. This study confirms the first distributional record of Seriola dumerili from the eastern Arabian Sea.

Reduction in marine fish production in the last two decades has adversely affected the fishermen population along the coasts who solely depend on fishing for their livelihood. One option to tide over this situation is regional level planning to increase fish production from available water resources. Therefore, it is essential to have an integrated spatial planning of the available water resources as it has multiple uses. Marine spatial planning (MSP) and aquaculture zoning, the two major concepts implemented by international bodies, are still in its infancy in India due to, lack of information on its systematic implementation. Present paper describes the pioneering attempt of “Spatial planning” and “aquaculture zoning” in India, conducted in a progressive fishermen village, Tharapathi in Byndoor along Southeastern Arabian sea coast, following scientific methodologies. Through GIS mapping, potential aquaculture areas were identified for cage farming, bivalve farming, crab fattening/crab culture in pens in mangrove area, bottom culture of clams in sandy area, prawn farming areas, areas for seed production and nursery facility for finishes and shellfishes etc. Various advanced GIS based decision making tools available for future integrated aquaculture development plans, spatial mapping and Digital Elevation Models were included in this study. This is the first attempt to develop integrated aquaculture development through social consensus and scientific evaluation. Results of the study will be a precursor for spatial planning and aquaculture zoning in Indian coastal waters for sustainable aquaculture.

Rising crisis in marine environment is the presence of plastics in the water column and risk of their input and accumulation in the food web. The present study reports for the first time, the presence of micro and macro plastics in the gut of razor moonfish, Mene maculata. Moonfish plays a major role in the marine food web as prey of large pelagic fishes. The gut analysis of fishes collected from commercial vessels operating along eastern Arabian Sea was analysed to determine the occurrence and abundance of plastic particles with attempt to identify the diet component which might have contributed to the plastic intake in fish. The analysis revealed dominance of plastic particles in gut when dietary component was dominated by eggs. The present study forms baseline information for plastic accumulations in fishes along the eastern Arabian Sea

Investigations were carried out to determine the nutritional profile of Indian Ocean swimming crab Charybdis smithii, which is emerging as an unconventional resource in trawl discards of India. The average protein content was 9.38 g/100 g, fat 0.86 g/100 g, ash 0.34 g/100 g, fiber 0.13 g/100 g, and carbohydrate 1.8 g/100 g. One-way analysis of variance showed no significant variations of constituents except in dry matter and carbohydrate between sexes. Macronutrients, Na (317.1, 327.6/100 g), K (148, 177.40 mg/100 g), Ca (187.90, 285.80 mg/100 g), and Mg (34.31, 41.49 mg/100 g), showed significant variation between sexes. The composition of micronutrients in male and female were Cu (0.28, 0.15 mg/100 g), Fe (0.57, 0.71 mg/100 g), and Zn (1.71, 2.75 mg/100 g). Mineral content showed significant difference between sexes. Amino acid analysis showed that 12.04 and 11.47 g/100 g essential amino acid glycine was present in male and female, respectively, and lysine concentration was 13.96 and 12.65 g/100 g, respectively. The nutritional profile of the species was determined the first time and shows that it is comparable with any other edible crabs and could be exploited as a commercial resource to supplement nutritional demand.

Length-weight relationship (LWR), condition factor, sex ratio, gonadosomatic index (GSI) hepatosomatic index (HSI) of the smooth blaasop puffer fish Lagocephalus inermis (Temminck and Schlegel, 1850), an emerging fishery resource along south-eastern Arabian Sea were studied from 1,722 samples collected during August 2017-May 2019 from Mangalore Fishing Harbour, Karnataka, India. LWR indicated negative allometric growth [W = 0.034805L2.76 (males); W = 0.033574L2.78 (females), W = 0.033979L2.77 (pooled)] and significant difference was observed in the b value of the fishes. Sex ratio was 1:1.08. The ratio was unusually high during post-monsoon and Chi-square test revealed that the monthly sex ratio did not vary significantly throughout the year except for December and January (p

Red sea bream iridovirus (RSIV) is an emerging viral pathogen having significant socio-economic and environmental impacts on marine and brackish aquaculture systems. The study documents certain interesting findings of an RSIV disease outbreak that caused 50% cumulative mortality among cage farmed Asian sea bass in India. The confirmatory diagnosis was made based on internationally approved protocols. The affected fish showed splenomegaly, anaemia, and abnormally enlarged cells within the spleen, liver, kidney, and brain. The consistent presence of two fish pathogens, viz., Vibrio alginolyticus and Vibrio fluvialis, in the liver, along with characteristic vibrio-induced pathologies were noted, indicating the possible role of these bacterial pathogens in RSIV pathogenesis during the outbreak. More strikingly, the surviving fish were found to carry the virus even after two months post-outbreak, warranting future investigations on the carrier status of RSIV survivors. Transmission electron microscopy in the survivors demonstrated atypical virus particles within the degenerated cells of the vital organs, suggesting the role of host immune response in preventing the maturation of RSIV particles in the survivors. Phylogram based on MCP and ATPase genes demonstrated the spread of the same RSIV clone across different countries, regardless of the fish species. Results also revealed the presence of two RSIV subtypes. Both subtypes were mainly distributed in marine demersal fishes of Asian countries. Presently, subtype 2 is the most frequently reported one. Subtype 1 revealed higher genetic diversity with a wider geographical spread and host range. Molecular analyses revealed that MCP and ATPase genes could be targeted in RSIV subtyping, with MCP as a better candidate. A purifying selection was observed on the MCP gene that can be applied for diagnostic protocols. In short, the study generates certain thought-provoking insights on RSIV through the analyses of a recent outbreak along with the genetic and epizootiological data of global strains. Further, the paper also forms the first report on the presence of RSIV in surviving fish post-disease outbreak in the absence of clinical signs. Altogether, the results highlight the necessity of strengthening quarantine and RSIV diagnostic measures to have sustainable aquaculture practices.

The effectiveness of GIS-based resource mapping to strengthen the database for Ecosystem-Based Fisheries Management (EBFM), was tested in an attempt at resolving the existing gap in the data on non-commercial resources. In this paper we describe the result of that try by giving an example of one of the most important influential species in the benthic ecosystem of the Southeast Arabian Sea (SEAS). An estimated 2803 t of Charybdis hoplites, a relatively little known species from the coast, are yearly caught and discarded by trawlers operating from the Mangalore fisheries harbour. A GIS-aided study on distribution and abundance estimated, that the average biomass of the species is 322.7 t, at any time in the area covered. This study brings out the fact that a number of non-commercial biota are serving as non-detectable factors in sustaining productivity. The identification of their role and the quantification of their biomass thus constitute important data for an effective implementation of EBFM.

Ever since marine fishery operations were extended beyond territorial waters of respective states, the need was felt for incorporating spatial component of fishing effort and catch for formulating marine fishery policies. The present study is an attempt of spatio-temporal analysis of changing scenario of fishing operations in GIS platform with catch and effort data collected from fishermen, to highlight the need for the change in approach in fisheries management and also for updating the information of fishing along the Indian coast. Marine fishing operations by commercial fishing vessels operated from different states has extended up to 200 m depth since 2000 and duration of fishing, especially trawling extended from single day to 8-13 days per voyage. Present findings were drawn from the analysis of 1,217 days of trawling operations during 2007-2013 by a sampling trawler supplemented by additional fishing operational data support from a group of commercial trawlers. Study reveals that there is an organised and confidential maintenance of log sheets in most of the progressive trawler operators and the information available in spatial platform can be utilized for better fisheries management with fishermen’s participation. Spatial analysis of fish catch from the sampling trawler operated from Mangalore showed that more than 70% of the fish landed in Mangalore was brought from the area beyond the territorial waters of Karnataka signifying that majority of fish catch landing to the state is from waters beyond their jurisdiction. Even though the fishery beyond territorial waters of all maritime states is s governed by Government of India, so far, there is no comprehensive management plans regarding fishing operations beyond territorial waters of the states. The study further reveals that fishing grounds beyond territorial waters of each state are being intensively fished without any fishing regulations and there were many conflicts being reported from these waters concerning the fishing rights of different sectors and different states. In the light of the findings from the study on fishing operations and fishery, an action plan to regulate the fishery off the territorial waters of each state is felt essential. “Regional fisheries committees” with members constituting the officials from neighbouring states sharing same resources with the aegis of Central Government is recommended as a viable option to take care of the management of the fishery within the Indian EEZ.

The relative abundance and biological characteristics of the spadenose shark Scoliodon laticaudus, from the south eastern Arabian Sea along Karnataka, India was studied. The average annual catch of the species during the period 2012–2017 was estimated at 112 t which formed about 13% of the total shark landing in the region. The species is landed mostly by trawl nets. Monthly abundance estimates showed that highest landing of the spadenose shark was observed in January. A total of 852 specimens were studied for biological characteristics. The length range of 19–63 cm was observed and length group of 45–55 cm formed the mainstay of the fishery. The length weight relationship for male and female and sexes pooled were 0.06588 L2.2386; 0.01118 L2.7497 and 0.01396 L2.6840 respectively. Analysis of covariance showed significant differences between the male and female ( p 0 . 05 ). In the present analysis, the regression co-efficient ( b value) for the species differs significantly from the value 3 indicating allometric growth. Lm50 for female and male were estimated as 32 and 33 cm. Chi-square-test on monthly sex ratio for the period showed that there was significant difference in sex ratio only in the months of January, October and November. S. laticaudus was found to be predominantly piscivorous in diet. The fishery is declining and efforts have to be taken for sustainable exploitation of resources.

The present study aimed to elucidate the length-weight relationship and growth parameters of the moonfish Mene maculata (Bloch and Schneider, 1801) along the Karnataka Coast. The species showed positive allometric growth with pooled ‘b’ value of 3.390 which is significantly greater than 3 (p

Scomberomorus commerson were collected on weekly basis during January 2012 to December 2014 at Mangalore Fishing Harbour. Stomach of 214 narrow barred Spanish mackerel measuring from 48 to 105 cm fork length (FL) for males and 45.5 to 115 cm FL for females were analysed to study their feeding habits. Fish with empty stomach were prevalent in almost all the months. Prey mainly comprised of fishes and crustaceans, with the fish component forming 99.9%. The index of relative importance (IRI) showed that the dominant prey were semi-digested fish remains (44.6%) of Sardinella longiceps (30.1%), Decapterus sp. (18.7%), whitebaits (2.5%), Rastrelliger kanagurta (1.5%) and Epinephelus spp. (1.1%), while Saurida sp. (0.7%), Megalaspis cordyla (0.5%), Scombroides sp. (0.2%) and shrimps (0.1%) were found occasionally in the gut. Index of stomach fullness (SFI) was 0.11 in August and 0.65 in January. Generally, SFI was higher during September to January and lower during February to August. The empty stomach ratio (ESR) ranged from 33.3% (August) to 92.3% (April).

Internationally, marine spatial planning (MSP) is an integral part of the decision-making protocol for setting up activities in the marine zone, be it the establishment of industries, exploration and mining for oil and minerals, deciding of surface transport, ensuring national security, exploitation of living and non-living resources, or conservation and management of resources and ecosystems. Satellite-based technologies like remote sensing and geographic information system are two powerful tools that provide a common platform to present information on different activities from the marine zone. This would enable the planners and policymakers to interpret the interaction between various factors and derive judicious decisions on the allocation of space and resources to different segments or activities in marine zone. This article reviews how MSP is being used as a decisionsupport tool in various countries for the peaceful coexistence of different stakeholders in the marine zone. It also discusses initiatives in India along with a reminder on the responsibility of the country as a signatory of international organizations to give importance on developing MSP for the conservation of resources as well as marine ecosystems.

Environmental parameters influence the productivity and abundance of fish in marine ecosystems. In this study, we attempted to analyse the relationship between environmental parameters and abundance of fish in trawling grounds in south-eastern Arabian Sea along the coast of Karnataka. Among the 85 species of finfishes and shellfishes caught in the trawling grounds, 41 finfish species, 24 crustaceans, 18 molluscs and two echinoderms were recorded. Seasonal differences were seen in biomass with the highest biomass during the post-monsoon period (October-January). Water temperature and nutrients were the key contributing factors of seasonal differences in the biotic communities studied. Season specific diagnostic species were identified using SIMPER analysis. Squilla which formed the major prey item of most of the demersal fishes dominated (>40%) coastal grounds throughout all seasons. This could be considered as a fishery indicator of the region. The dominance and abundance of copepods was found to be influenced by sea surface temperature (SST) and nutrients. The results of the study have implications on the fishery, knowledge on environmental factors influencing the abundance and importance of non-commercial species in sustaining the fishery in the region.

The feeding regime of organisms depend on the plankton community structure which is being studied worldwide to assess the changes in marine ecosystem structure due to climate change or anthropogenic activities. An attempt is made here to study the seasonal and long term variation in feed composition of Indian mackerel over a period of 40 years and its relationship with sea surface temperature to elucidate structural changes in food composition if any over period of time and its relationship to the primary and secondary productivity in eastern Arabian Sea marine ecosystem. The diet study during 2011-2014 reported the domination of phytoplankton consisting of Coscinodiscus sp. consistently and the presence of macroplankton and fish larvae whereas the diet during 1960-1961 showed the dominance of zooplankton and copepods. It could be assumed that increase in sea surface temperature which resulted in dominance of phytoplankton community as reported elsewhere in the world is also observed in eastern Arabian Sea which is reflected in the diet regime of Indian mackerel. The results also indicate its facultative feeding behaviour by compensating the low value phytoplankton with high value macroplankton and hence can be considered as a resilient species with regard to climate change.

The composition and seasonal abundance of the fin and shellfish seeds in mangrove areas of Gangoli estuary were studied for one year from January to December, 2013. Monthly day time sampling was conducted with a rectangular dragnet of 75 m2 length having 5 mm mesh size. The mean monthly density was highest in January (Avg. of 12,996/haul) and lowest during May (Avg. of 859/haul). Thirty species of fish, four species of shrimps and two species of crabs belonging to 26 families were recorded during the study. Ambasis sp., Feneropenaeus indicus, Etroplus suratensis,Leognathus sp., Liza sp., Stolephorus vaganensis, Hemiramphus sp., Terapon sp. and Gerres sp. were the most abundant species/taxa. A total of 10 commercially important species comprising F. indicus, Etroplus suratensis, Liza sp., Gerres sp.,Siganus sp., Lutjanus russei, Macrobrachium rosenbergii, Lutjanus argentimaculatus, Sillago sp. and Penaeus monodon constituted 8.5% (April, 2013) to 93.7% (October, 2013) with an average of 37.2% of the total fish and shellfish seeds. Higher Species diversity (H') and Species richness (D) was recorded during January. The result of the present investigation gives an insight of the abundance and seasonality of commercially important fish and shellfish seeds, which may facilitate the brackishwater fish farmers to exploitthe seeds more pragmatically for their culture practice.