Vermiculated sailfin catfish, Pterygoplichthys disjunctivus (Actinopterygii: Siluriformes: Loricariidae): Invasion, biology, and initial impacts in East Kolkata Wetlands, India

Abstract

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.

Suckermouth armoured catfish (Pterygoplichthys spp.) menace in freshwater aquaculture and natural aquatic systems in Andhra Pradesh, India

“…Mean annual fish harvest data in East Kolkata Wetlands revealed that Pterygoplichthys spp. constituted 4.83% of total fish catch (Suresh et al 2019) [30] that almost conforms to 4.63% in the current study. However, Moorthy et al (2016) [10] recorded very high degree invasion of Pterygoplichthys spp up to 80% of the total fish community harvested in River Cauvery, India thus alarming about invasive pressure on native species.…”

“…al. 2019) [28] , Kerala (Suresh et al 2019) [30] , Tamilnadu (Sandilyan, 2019) [61] . In the present study, invasion of Pterygoplichthys spp was assessed in terms of biomass registered in carp culture ponds as well as canal and river systems.…”

Phenotypic Divergences in Growth and Reproduction Underpin The Invasion of Suckermouth-Amored Catfishes to Lotic and Limnic Habitats in Vietnam

“…The relative fecundity of Pterygoplichys spp. in this study was comparable to P. disjunctivus from El In ernillo Reservoir, Mexico (RF t = 12.5 eggs/g) (Rueda et al 2013) and East Kolkata Wetlands, Indian (RF t = 8-22 egg/g)(Suresh et al 2019).The average diameter of the top size class eggs in Pterygoplichys spp. from Dinh River was moderately larger (~ 13%) than that of sh from Suoi Trau Reservoir, which may relate to the adaptive responses to different habitat conditions.…”

“…was 19.2 cm L s in El In ernillo Reservoir, Mexico (Rueda-Jasso et al 2013) and 26 cm L s in Volusia Blue Spring Florida, USA(Gibbs et al 2008;Gibbs et al 2017). In Asia, the 50 percent sexual maturity was 24 cm L t of P. disjunctivus in East Kolkata Wetlands, Indian(Suresh et al 2019) and Taiwan was 25 cm L s of P. multiradiatus from Kaoping river(Liang et al 2005), and was 26 cm L s of P. disjunctivus in Marikina river, Philippines (Jumawan and Herrera 2014). In our study, the size at rst maturation of sh is smaller than sh in native and other studies (similar to P. pardalis in Peninsular river, Malaysia, 13 cm L s ,Samat et al 2016).…”

“…In other geographical areas with only two seasons (rainy and dry seasons), the main reproductive season of Pterygoplichthys occurs in the rainy season. For example, in Malaysia, the P. pardalis reproduce from September to January(Samat et al 2016), the P. disjunctivus from June to September in The Philippines (Jumawan and Herrera 2014) and from July to November in India(Suresh et al 2019). P. disjunctivus could change their reproductive strategy to adapt to the local environment(Gibbs et al 2017).…”