Channel Catfish Review Life-history, distribution, invasion dynamics and current management strategies in the Pacific Northwest Thomas K Pool University of Washington Figure 1 Illustration of a channel catfish by Ted Walke (http://www.fish.state.pa.us/pafish/chancatm.jpg) Figure 2 Thomas L. Wellborn SRAC Publication No. 180 http://www.tpwd.state.tx.us/huntwild/wild/species/ccf/) Figure 3 Channel catfish: Note the barbels Figure 4 Channel catfish: Characteristic deeply forked located near the mouth© George tail © George Burgess (http://www.flmnh.ufl.edu) Burgess(http://www.flmnh.ufl.edu) All information in this report was compiled in November, 2007. Current distribution maps and background information may be outdated at this time. Diagnostic information 1a) Adipose fin a flag-like fleshy lobe, well- separated from caudal fin; tail squared, rounded, Ictalurus punctatus (Rafinesque, 1818) or forked; adults to over 24 inches Kingdom Animalia-- animals 1b) Adipose fin long, low, and 'keel-like', nearly Phylum Chordata-- chordates continuous with caudal fin; tail squared or Subphylum Vertebrata-- vertebrates rounded; adults small, never over 6 inches Superclass Osteichthyes-- bony fishes 2a) Tail deeply-forked, lobes pointed; anal fin Class Actinopterygii-- ray-finned fishes, spiny with 24 to 30 rays; bony ridge connecting skull rayed fishes and origin of dorsal fin; head relatively small Subclass Neopterygii-- neopterygians and narrow; young with small spots, larger Infraclass Teleostei adults blue-black in color without spots channel Superorder Ostariophysi catfish Ictalurus punctatus Order Siluriformes-- catfishes Family Ictaluridae Overview Genus Ictalurus Species Ictalurus punctatus Channel catfish are often grey or silver in color and can be one of the largest catfish species with a maximum size up to 915 mm and Basic identification 13 kg. This catfish is used extensively as an aquaculture species in countries around the Basic Physical Characteristics (commonly used world. It is also a target species in the wild for for identification) many anglers given its large size and good taste. Upper jaw extends beyond lower jaw As a result of the human desirability of this species it now has many established populations Anal fin margin rounded with 24-29 rays outside its native range within North America. Tail fin forked It is an extremely resilient fish that can survive a Dark spots on lighter skin wide range of environmental variability and Lakes scales (all North American catfish) displays unique reproductive behavior different Presence of barbles around the mouth (all from many of its catfish cousins. At this time North American catfish) there is very little effort to control channel Key Traits (http://www.mcz.harvard.edu) catfish populations outside their native range. Origin and Distribution History of invasiveness in PNW Channel catfish are currently well established in the Columbia, Willamette and Snake Rivers waterways of Washington. In Oregon, the Columbia, Willamette, Umpqua, and Walla Walla rivers have established populations of channel catfish. In addition, the Figure 5 Main aquaculture producer countries of Boise River, Snake and Little Wood rivers of Ictalurus punctatus (FAO Fishery Statistics, 2002). Idaho have this species (USGS site). China and Brazil have added channel catfish farms since this figure was constructed. A map of wild populations established outside of aquaculture farms at a global scale is not currently available. The channel catfish has been part of the freshwater landscape in the PNW for over a hundred years. In 1892 and 1893 over 250 individuals were introduced into three lakes in Washington as well as 100 individuals in Boise River, ID, and Willamette River, OR (Boersma Figure 7 Pacific Northwest distribution map for channel et al. 2006). catfish. Tan area has no record of channel catfish. Light pink is non-specific state record of species presence. Dark pink and red have detailed catch records of species catch locations (HUC 6 & 8) (USGS http://nas.er.usgs.gov/queries/FactSheet.asp?speciesID= 2341). Life-history and basic ecology Life cycle Channel catfish are native to the Midwest and eastern North America extending Figure 6 USA distribution map for channel catfish. from Canada to Mexico (Page & Burr 1991). Brown area is native area and pink/red area is non- They are generally adapted for water with low native range (USGS visibility and are traditionally nocturnal http://nas.er.usgs.gov/queries/FactSheet.asp?speciesID foragers. Given this evolutionary history, many of the catfish species have olfactory sensors visual predators even though they are primarily located on their barbells and body. As a species nocturnal foragers and consume yellow perch they are omnivorous but their specific diet can and sunfish in addition to salmonids in the PNW very considerable depending on the region they (Wellburn 1988). In other areas of North are introduced and the specific habitat they are America such as Arizona, channel catfish have residing in within that region (Moyle 1976, exhibited very high predation pressure on Boersma et al. 2006). Specific predation and reintroduced natives species such as the reproductive life history is detailed below. razorback sucker that have significantly dropped in abundance in the lower Colorado River Feeding habits (Marsh & Brooks 1989). Juvenile salmon appear to be a Predatory impacts of channel catfish extend substantial portion of catfish diets in the PNW outside of fish taxa as well. The Chiricahua range. Individuals harvested from Columbia leopard frog is currently declining in numbers in River reservoirs had 50% to 100% of Salmon the southeastern Arizona. One study found that prey items in their gut contents depending on the predation pressure buy channel catfish may be catfishes size class (Boersma et al. 2006). It is high enough to influence the population estimated that an adult catfish may prey on dynamics of this frog species within this that juvenile salmon as much as one individual every area of the southwest (Sartorius & Rosen 2000). three days (Boersma et al. 2006). It is difficult Channel catfish also seem to influence the to estimate the total predatory pressure catfish growth rates and microhabitat use of native are putting on salmon populations because crayfish (Cambaridae) in Mississippi river accurate abundance data for this region has not mesocosm studies (Adams 2007). been complied. Although channel catfish do specialize in eating Reproductive strategies juvenile salmon, like many catfish, they are Channel catfish are monogamous with opportunistic feeders that will consume a large an interesting mating and juvenile rearing variety of taxa if alternate food sources are strategy. Individuals can be sexually mature as available (Lapman 1946; Moyle 1976). Channel early as 2 years of age and as late as 6 years of catfish tend to be piscivorous bottom feeders and age (Wellburn 1988). Spawning time varies can be found foraging in larger, swifter rivers with latitude but most individuals produce egg than many of their related Catfish counterparts. masses of up to 20,000 eggs during the months They are still effective predators in a wide range of April through July. The basic reproductive of environments being omnivorous as needed. cycle of this species can be altered significantly Surprisingly, they are considered fairly effective in aquaculture systems to promote maximum production volume. The natural mating process Farmed Spawning and farmed fish spawning are both outlined This species is used extensively in below given that this species is extensively spawning ponds for food production around the transported and introduced for food production. world. Males and females are placed in Wild Mating spawning ponds with containers to simulate Mating occurs in water temperatures ranging natural nesting sites. Actual mating is triggered from 21˚ to 30˚ C when a male and female align by altering pond temperatures that mimic the next to each other in opposite directions and environment during mating season. This wrap their tails around their mates head. traditional form of farming channel catfish does Shivering by the males stimulate the female to not allow for improved stock production release eggs which are then fertilized by the techniques so induced pair spawning is another males milt. Mating takes place in a cavity (nest) option employed within the industry. Catfish built by the male catfish, often under log jams or are injected with gonadotropic hormones and undercut banks (Mayhew 1987). The male paired in flow-through aquaria (Sneed and chases the female away from the mating cavity Clemens 1959). The female is anaesthetized after the egg mass is deposited within the nest. The female does not completely leave the nesting area however, continuing to protect the area from predators at a distance (McKaye et al. 1994). The males tend to the eggs by fanning the eggs during development and stir-up sediments to provide a food source for the juveniles once the eggs have hatched. The female is also a source of nutrition for the juveniles by releasing eggs above them as an added nutritional boost (McKaye et al. 1994). Recent genetic work has confirmed that channel catfish spawn as monogamous pairs each season. Microsatellite loci have determined that, in almost all cases, the male guarding the nest is the biological parent to the progeny with the female and they typically only mate once a Figure 8 Spawning bins with individual nesting containers for mating