Taxonomic name: Pterygoplichthys multiradiatus Hancock, 1828
Synonyms: Ancistrus multiradiatus (Hancock, 1828), Hypostomus multiradiatus (Hancock, 1828), Hypostomus pardalis (non Castelnau, 1855), Liposarcus jeanesianus (non Cope, 1874), Liposarcus multiradiatus (Hancock, 1828), Liposarcus pardalis (non Castelnau, 1855), Liposarcus varius (non Cope, 1872), Plecostomus pardalis (non Castelnau, 1855), Pterygoplichthys jeanesianus (non Cope, 1874), Pterygoplichthys pardalis (non Castelnau, 1855)
Common names: carachama (Spanish-Peru), long-fin armored catfish (English-Hawaii), orinoco sailfin catfish (English-Mexico, United States), plecóstoma del Orinoco (Spanish-Mexico), radiated ptero (English-United States), sailfin catfish (English-United States), sailfish catfish (English-United States), sejlfinnet sugemalle (Danish-Denmark), tummaleväpleko (Finnish-Finland)
Organism type: fish
lakes, water courses, wetlands
Pterygoplichthys spp. can be found in a wide variety of habitats, ranging from relatively cool, fast-flowing and oxygen-rich highland streams to slow-flowing, warm lowland rivers and stagnant pools poor in oxygen. They are tropical fish and populations are typically limited only by their lower lethal temperature which has been found to be about 8.8-11°C in some species (Gestring, 2006). They can thrive in a range of acidic to alkaline waters in a range of about (pH 5.5.0 to 8.0) (Mendoza et al., 2009). They are often found in soft waters, but can adapt very quickly to hard waters. Pterygoplichthys spp. are also highly tolerant to poor water quality and are commonly found in polluted waters (Chavez et al., 2006). They are known to use outflow from sewage treatment plants as thermal refugia and can readily adapt to changing water quality (Nico & Martin, 2001). Pterygoplichthys spp. may be found in from lowlands to elevations of up to 3,000 m (Wakida-Kusunki, 2007). Some species are salt tolerant (Mendoza et al., 2009).
Potential effects of Pterygoplichthys spp. include alteration of bank structure and erosion, disruption of aquatic food chains, competition with native species, mortality of endangered shore birds, changes in aquatic plant communities, and damage to fishing gear and industry.
Environmental impacts of Pterygoplichthys spp. are not fully understood, but in locations where they are introduced and abundant, their feeding behaviours and burrowing activities can cause considerable disturbance. Their burrows have been reported as contributing to siltation problems and bank erosion and instability (Hoover et al., 2004; Nico et al, 2009b). Pterygoplichthys spp. forage along the bottoms of streams and lakes, occasionally burying their heads in the substrate and lashing their tails. These behaviours can uproot or shear aquatic plants and reduce the abundance of beds of submersed aquatic vegetation, creating floating mats that shade the benthos from sunlight. By grazing on benthic algae and detritus, they may alter or reduce food availability and the physical cover available for aquatic insects eaten by other native and non-native fishes where they are introduced (Mendoza et al, 2009; Hossain et al, 2008). Pterygoplichthys spp. may also compete with native fish. They are believed to displace several species of minnow in Texas including the Federally threatened and 'Vulnerable (VU)' Devils River minnow (see Dionda diaboli ) (Cohen, 2008; Mendoza et al, 2009). Pterygoplichthys spp. have also been found to ingest eggs of Etheostoma fonticola, also listed as vulnerable (Cook-Hildreth, 2009).
Pterygoplichthys spp. are thought to create large, novel nutrient sinks in invaded streams of southern Mexico. They sequester the majority of nitrogen and phosphorus of systems in their body armor. These impacts on nutrient systems may also exacerbate the nutrient limitation of primary productivity in invaded streams (Capps et al, 2009).
Thousands of nesting tunnels excavated by P. multiradiatus have contributed to siltation problems in Hawai'i. Because of their abundance in Hawai'i, P. multiradiatus may compete with native stream species for food and space (Nico, 2006). The burrowing behaviour and overpopulation of P. multiradiatus may also displace native fish in Puerto Rico where they have been reported as detrimental to reservoir fishes (Bunkley-Williams et al, 1994). In Lake Okeechobee, Florida P. multiradiatus feeds and burrows at the bottom and destroys submerged vegetation, essentially displacing native fishes that would otherwise use the aquatic vegetation for spawning and refuge and interfering with their reproduction (Mendoza et al, 2009). P. multiradiatus is known to cause economic losses to fisherman by damaging equipment such as cast and gill nets in India and displacing native fish (Krishnakumar et al, 2009).
P. multiradiatus and P. pardalis damage fishing gear and gill nets in various locations of Mexico (Wakida-Kusunoki et al, 2007).
P. disjunctivus and P. pardalis are reportedly destroying cages and nets and causing a decline in native, more desirable fish in Laguna de Bay, Philippines (Chavez et al, 2006). P. disjunctivus attaches to the skin of the 'Endangered (EN)' native Florida manatee (see Trichechus manatus ssp. latirostris ) and feeds on their epibiota. In some instances dozens of P. disjunctivus and manatees appeared agitated. This interaction may be detrimental to manatee but remains unclear (Nico et al, 2009a).
Native range: South America
Known introduced range: United States, Puerto Rico, Hawai'i, Mexico, Guatemala, Philippines, Singapore, Thailand, Bangladesh, Indonesia, Taiwan, India, Japan
Introduction pathways to new locations
Live food trade: While no substantial trade in catfish is thought to occur, the live food trade cannot be discounted completely as a potential mechanism for spread to new locations (Mendoza et al., 2009).
Other: Accidental release of Pterygoplichthys spp. has been documented, such as when typhoon Rosing struck the Philippines resulting in escape of the fish from commercial farms (Hubilla et al., 2007).
Pet/aquarium trade: Pterygoplichthys spp. are very common aquarium fish throughout the world. Nearly all of their introduced populations are believed to be the result of pet release or aquaculture escape (Page & Robins, 2006).
Local dispersal methods
Intentional release: Some populations of Pterygoplichthys spp. are thought to have arisen through the intentional release of unwanted fish by owners (Hubilla et al., 2007).
Natural dispersal (local):
Preventative measures: Efforts to prevent the establishment of Pterygoplichthys spp. are recommended in potential habitats. Educating the public, especially aquarists, to avoid releasing their unwanted fishes into open waters may reduce their introductions (Mendoza et al, 2009).
Physical: It may be possible to reduce abundance in some locations, but based on the Hillsborough River studies, eradication is not feasible. Environmental management would only be useful in highly modified habitats located in urban areas. It is doubtful that it is possible to control populations over large areas. Shoreline hardening/barriers are effective, but expensive. A larger, commercial fish market for Pterygoplicthys coupled with intense egg collection could reduce their abundance. Some researchers recommend visiting nesting colonies during the breeding season and capturing and removing adults and any eggs and young. This method may be mostly effective in areas where breeding habitats are limited (Medoza et al, 2009).
Pterygoplichthys spp. feed primarily on benthic algae and detritus (Ozedilek, 2007). They may also consume worms, insect larvae, fish eggs and other bottom-dwellers but the vast majority of its diet consists of detritus, algae, and various plant matter (Mendoza et al., 2009).
Pterygoplichthys spp. reproduce sexually and have high fecundancy (Gibbs et al, 2008). Males construct horizontal burrows in banks that are about 120-150 cm long extend downward. The burrows are used as nesting tunnels and eggs are guarded by males until the free-swimming larvae leave. Females may lay between 500-3,000 eggs per female depending on size and species. Their reproductive season peaks in the summer and usually lasts several months but may be year-long in certain locations (Mendoza et al, 2009).
Growth of Pterygoplichthys is rapid during the first two years of life, with total lengths of many sailfin catfishes exceeding 300 mm by age 2. Specimens in aquaria may live more than 10 years. The size range for most of the adult species in the Loricariid family is 30–50 cm, but individuals have been observed to reach 70 cm. Pterygoplicthys spp. start reproducing at approximately 25 cm (Mendoza et al, 2009).
Reviewed by: Dr. Roberto Mendoza, Universidad Autónoma de Nuevo León (UANL).
Compiled by: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG)
Last Modified: Wednesday, 23 June 2010