Small indigenous fishes (SIF) play a crucial role in supporting the livelihoods and nutritional security of the rural population in Southern Asia. However, their abundance and diversity are under threat due to overexploitation and profitable extensive aquaculture, resulting in a sharp decline, particularly in India. Unfortunately, conservation strategies for SIF have received little attention from researchers, making it imperative to understand stakeholders’ decision-making processes to develop effective conservation strategies. This article aims to quantitatively identify the factors that influence fishermen’s intention to participate in and pay for SIF conservation efforts. The study utilizes questionnaire-based survey data from 100 households engaged in local fisheries in the rural Indian Sundarbans. To gain critical insight into fishermen’s decision processes, a bivariate logistic Generalized Additive Model is employed, focusing on willingness-to-participate and willingness-to-pay for SIF conservation. The study’s results indicate that several factors significantly influence fishermen’s willingness-to-participate in conservation efforts. These include Literacy, Conservation awareness, and Occupation. On the other hand, Conservation awareness and Household income are identified as significant determinants of fishermen’s willingness-to-pay for SIF conservation initiatives. One intriguing finding of the research is the identification of a nonlinear response-age curve for both willingness-to-participate and willingness-to-pay, as well as their interaction. Notably, the 45-50 years old age group emerged as the most likely implementers of small indigenous fish conservation strategies, suggesting that targeting this age group in conservation programs could yield positive outcomes. The study underscores the importance of various conservation strategies to bolster SIF preservation in the region. Recommendations include increasing and extending conservation awareness programs, specifically targeting suitable age-group individuals with appropriate education, household income, and occupation. These strategies are vital for formulating effective conservation guidelines that align with the specific needs and characteristics of the region. In conclusion, this research sheds light on the factors influencing fishermen’s participation and willingness to financially support the conservation of small indigenous fish in the rural Indian Sundarbans. The findings contribute valuable insights for policymakers, conservationists, and stakeholders, emphasizing the urgency of sustainable measures to safeguard SIF populations and ensure the continued livelihoods and nutritional security of the local communities.@en

Background. The East Kolkata Wetlands in India (a Ramsar site) are sewage-fed, nutrient-rich water bodies successfully used for fish production. The vermiculated sailfin catfish, Pterygoplichthys disjunctivus (Weber, 1991), exotic to India, has invaded these wetlands. The management and control of this catfish has been hindered, because of the lack of information on its abundance, population structure, biological traits, level of establishment, and competition with native fish species. Materials and methods. Within 2013–2015 studies were carried out on the population structure of P. disjunctivus, its food habits, reproductive biology, and initial impacts in the wetlands through monthly and seasonal collection of samples, examination of food items, reproductive parameters, catch data, and gathering fishers experience. Results. The length (TL) and weight of the specimens ranged from 10 to 55 cm and from 120 to 1250 g, respectively. Major food items of the catfish were detrital matter (%IRI 56), unidentified plant matter (%IRI 11), fish eggs (%IRI 11), polychaete worms (%IRI 5), and other minor items (%IRI 0.3 to 4). At 50% similarity, the food items of P. disjunctivus overlapped with that of Macrognathus pancalus, Channa punctata, Nandus nandus, Anabas testudineus, Clarias batrachus, Oreochromis niloticus, Cirrhinus mrigala, and Cyprinus carpio while at 80% it overlapped with that of C. mrigala and C. carpio. The fecundity of P. disjunctivus, in the wetlands, was the highest recorded for the species. Females attained the first maturity at 24 cm TL and reproduced multiple times within July–November. The breeding period of the species overlapped with 13 native fish species, of which it seriously overlapped with that of Gudusia chapra, Amblypharyngodon mola, Pethia conchonius, P. ticto, N. nandus, C. punctata, and A. testudineus. The sailfin catfish has established reproducing populations in the wetlands and reached ‘invasive’ proportions constituting 4.83% (300.04 t · year–1) of the mean annual fish catch (6203.85 t · year–1) from the wetlands. The invasive risk assessment showed a high risk of the species in the current scenario and probable climate change scenarios in future in the region. Conclusions. Pterygoplichthys disjunctivus has successfully colonized the sensitive East Kolkata Wetlands, which might easily spread to neighbouring water bodies including the sensitive Ganga River and Sundarban mangroves and cause ecological and economic disturbance unless preventive measures are taken as the species has high invasive risk in the region.@en