Exploring biophysical links of catch rate from mid-water trawl fishery in the north-west coast of India, Eastern Arabian Sea: A remote sensing approach.

Fish frequently shift their distribution ranges as a result of changes in preferred environmental factors. Knowledge on distribution of fish in relation to their environmental optima is crucial for improving the understanding of fishing grounds and planning sustainable exploitation. This study investigated the monthly variability in environmental factors impacting the catch rate and the spatio-temporal distribution patterns of fish along northwest coast of India (NWCI) from 2017 to 2019. The time series images of sea surface temperature (SST), sea surface height anomaly (SSHa), chlorophyll-a concentration (CHL), and euphotic depth (Zeu) indicate close coupling between bio-physical variables in the region. Generalized Additive Model (GAM) applied to the catch rate of mid-water trawlers found that CHL and Zeu were the most influential variables for ribbonfish distribution, while CHL and SST influence squid distribution and SST and SSHa influence cuttlefish distribution. The total deviation explained 37.70 %, 10.70 %, and 22.28 % in the final model for simulating the spatio-temporal distribution of ribbonfish, squid, and cuttlefish, respectively. Environmental factors were significant in the final GAM model (p < 0.05). Spatio-temporal distribution patterns of fishery resources from mid-water trawlers showed that they were related to biophysical changes in the northwest coast of India. The high catch rate was observed in the northern latitudes during the post-monsoon (October), the major fishing season in the region. However, it shrank and shifted to southern latitudes during the winter (January). This study could be adapted to nearby countries in the Arabian Sea region for an effective and useful tool to monitor and manage the fishery resources. Furthermore, it could aid in decision-making for policymakers and resource managers to formulate strategies for holistic marine fishery management and sustainable resource exploitation.

Intercropping of marine finfish in shrimp ponds: A maiden feasibility study.

Diversification of shrimp farming with marine finfish in a farmer participatory research model was attempted. The study is intended to find an economically viable finfish culture during the fallow period of shrimp farms. The Silver pompano, Trachinotus blochi iintercropped with Pacific white shrimp, Litopenaeus vannamei culture in coastal shrimp ponds was assessed for growth, survival, and economic viability. During the grow-out period of 100 days, fishes grew from 40.23 ± 1.40 g to 256.56 ± 1.08 g in weight and 12.83 ± 0.19 cm to 25.11 ± 0.09 cm in length. The daily weight gain (DWG) and daily length gain (DLG) were 2.16 g/day and 0.12 cm/day, respectively. Relative growth rate (RGR) and specific growth rate (SGR) recorded for weight was 537.80% in 100 days and 1.85% per day, respectively. Pompano has exhibited its sturdiness and adaptability to the land-based culture system as evidenced by an overall survival percentage of 89.8% including nursery and grow-out phases. The realized feed conversion ratio was 1.94. The culture period of 100 days is found to be enough to attain a desirable harvest size of 250 g. The projected production potential of the experimental demonstration farm of 4500 m2 water spread area for culture was 16.2 tonnes/cycle with a benefit-cost ratio (BCR) of 1.34 over operational cost. The present participatory trial empirically proved the viability of Silver pompano as an intercrop in coastal shrimp ponds. Thus, the introduction of Pompano in shrimp ponds is recommended and can be promoted for sustainable intercropping with shrimp farming along the Indian coast for improving people's livelihoods.