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Abstract

The paper discusses the correlation between the Catch per Unit Effort (CPUE) of fishes with the phytoplankton biomass (chlorophyll-a) and nutrients in the West Bengal marine fishing zone (northern Bay of Bengal) during the post-monsoon season of 2010-11 and 2011-12. A total of 12 Potential Fishing Zone forecasts were simultaneously validated on board, covering 70 random samplings points wherein the physico-chemical parameters were also measured. A strong positive correlation of the CPUE with phytoplankton biomass was observed. The CPUE also positively correlated with the essential nutrients like dissolved inorganic phosphate (DIP), dissolved inorganic nitrate (DIN) and silicate. Four components were figured out in the principal component analysis out of 11 environmental variables. The first component primarily consisted of salinity, Secchi depth (positive loadings), turbidity and dissolve oxygen (DO) (negative loadings). Increases in component 2 were associated with increases in nutrients (silicate, nitrate and phosphate). The CPUE was much higher (8.15±6.08 kg/hour) in the PFZ forecast zones compared to the areas outside the forecast area (3.51±1.61 kg/hour).

Synergistic use of UAV surveys, satellite tracking data, and mark‐recapture to estimate abundance of elusive species

“…Sometimes census data involve direct counts of animals visible onshore, such as nesting seabirds or seals with pups (Clarke et al, 2011; Russell et al, 2019). In other cases, a population is sampled and numbers or biomass per unit effort are recorded, as in plankton, benthos, and fisheries surveys (Dutta et al, 2016; Keller et al, 2010). Yet despite the broad success of these approaches, in some cases, census data remain difficult to obtain, such as for elusive, rare, or widely distributed species or life history stages (e.g., beaked whales; Hildebrand et al, 2015).…”