Syndication of sink-source and area-based resource management as a remedy to sustain a small-scale fishery: The case study of blue swimming crab fishery from Sri Lanka

Abstract

Tropical small-scale fisheries (SSF) have become more vulnerable to over-exploitation due to: delayed alarming stock status, consequences of implementing deprived management strategies, data-poor scenarios, ambiguous assessment approaches and failures in a comprehensive understanding of the context of specific resource users. Hence, the current study on the blue swimming crab (BSC) fishery off the northern coast of Sri Lanka (September 2017 to November 2018), reveals the evidence of the SSF's requirement for a precise management and decision approach for sustainability. Therefore, here we intended, to evaluate The TropfishR package of the electronic length frequency (ELEFAN) method with new optimization techniques for data-limited fisheries analysis with length frequency (LFQ) data. Further multivariate techniques were used for the follow-up analysis. Results of LFQ data obtained through scrutinized ELEFAN methods and followed-up analysis showed that all studied fishing grounds are overexploited (E > 0.5) due to the “effort-creep” in post-war context and higher economic demand of BSC, which were collectively drive the prevailing behaviour of fishers. Further, due to cultural constraints such as caste-based gear choices and fishing ground choices, the small and immature stages of BSC become more susceptible to gears with low selectivity, which frequently operated in the estuary (ES) and shallow coast (SC). So under this multi-gear, complex SSF scenario banning or restricting the harmful gears becomes socially impossible. Hence, area-based management through a sink-source approach that characterizes the fishing ground with respect to the gear, seems to be promising. Therefore, we conclude that through a such robust approach, we could able to replenish a similarly overfished fishery scenario in the SSF.