Invasion of South American suckermouth armoured catfishes Pterygoplichthys spp. (Loricariidae) in Kerala, India - a case study

Abstract

This paper documents the occurrence of the exotic South American suckermouth armoured catfishes (Loricariidae) of the genus Pterygoplichthys spp. in the drainages of Thiruvananthapuram City, Kerala. The morphological taxonomy revealed that the specimens are closely related to Pterygoplichthys disjunctivus (Weber, 1991) and P. pardalis (Castelnau, 1855), in addition to intermediary forms of unknown identity. DNA barcoding using the mitochondrial DNA cytochrome c oxidase 1 (CO1) also failed to establish the identity of the invaded species. There may be possible hybridisation in aquariums or in fish farms or in the wild, but this needs to be found out aided by detailed studies incorporating different molecular markers and with sequences of topotypes. The possible threats due to Pterygoplichthys spp. invasion and management options are discussed in the paper.

Occurrence of Ornamental Fishes:A Looming Danger for Inland Fish Diversity of India

“…A study by Bijukumar et al 16 in the drainages of Thiruvananthapuram city, Kerala, revealed a constant declining trend in native species yield due to high invasion of suckermouth fishes (Figure 1). The number of fishes collected by the cast net each time varied from 3 to 27 throughout the study period, which indicates the dominant biomass of the species in the system 16 . Interestingly, another species of suckermouth catfish Pterygoplichthys pardalis was reported to cause huge damage to the native species diversity of Vandiyur Lake, Madurai, southern India.…”

“…It also creates serious negative impacts on periphyton-feeding and bottom-spawning fishes. Besides, it consumes the eggs of native species, which leads to local extinction of indigenous varieties 16 . A study by Bijukumar et al 16 in the drainages of Thiruvananthapuram city, Kerala, revealed a constant declining trend in native species yield due to high invasion of suckermouth fishes (Figure 1).…”

“…Besides, it consumes the eggs of native species, which leads to local extinction of indigenous varieties 16 . A study by Bijukumar et al 16 in the drainages of Thiruvananthapuram city, Kerala, revealed a constant declining trend in native species yield due to high invasion of suckermouth fishes (Figure 1). The number of fishes collected by the cast net each time varied from 3 to 27 throughout the study period, which indicates the dominant biomass of the species in the system 16 .…”

“…Likewise, studies from Kerala have shown the high occurrence of tilapia species in inland waters (up to 25%), due to which native species such as Puntius dubius and Labeo kontius face local extinction 13 . Also, overpopulation of ornamental sucker mouth catfish Pterygoplichthys multiradiatus and Pterygoplichthys pardalis has resulted in the decline of commercially important inland native fish in Kerala and Tamil Nadu, respectively 15,16 . In India, 31 aquaculture species, 600 ornamental varieties and 2 species of larvicidal fish have been identified as exotic 17,18 .…”

Species Composition and Abundance of Freshwater Fishes in Selected Rivers of Johor, Malaysia

“…There were three exotic species recorded namely Oreochromis nilotica, Hypostomus plecotomus and Poecilia sphenops. [12] reported that the exotic fish, Hypostomus plecotomus or also known as Suckermouth Catfish have successfully invaded water bodies of various countries worldwide including Malaysia, Singapore, Philippines, Japan and Europe. This species is widely used as a natural method to remove algae in an aquarium.…”