Scientific Name (Linnaeus): Lepomis gibbosus Stephannie Spurr Fish 497 Fall 2008 Diagnostic Information native range, pumpkinseeds reach an average Order: Perciformes length of 127-190 mm. In their Non-native Family: Centrarchidae, habitats they are smaller, on average 80-100mm. Genus:Lepomis This has been attributed to a change in resource Species: gibbosus allocation from growth to reproduction in order Common Names: Pumpkinseed sunfish, yellow to increase their establishment in a novel sunfish, common sunfish, sunfish, round environment. Establishment in non-native range sunfish, punky, sunny, sun bass, pond perch, has also been successful as many introduced bream (Becker 1983) areas lack a native predator such as bass, and where bass is present, the native fish are a Basic Identification: Deep, laterally preferred prey rather than pumpkinseed. compressed body. Average length 127-190 mm. Phenotypic plasticity is also seen in their non- Short terminal mouth. Short, stubby gillrakers; native range in body shape allowing them to almost as wide as they are long. Olive colored exploit a larger range of habitat. Pumpkinseed sides with orange to red-orange belly and breast. fish have been widely stocked in the Pacific Blue and orange cheek stripes, and a red to Northwest for sportfishing by the WDFW. orange spot located posterior of the opercular Management of unauthorized stocking is flap. There are two dorsal fins, but they appear through the use of rotenone. The WSANS places as a single fin. Anal fin with spines, the pelvic pumpkinseed on their “Regulated Species” list fin is located thoracic, and the pectoral fin is where as they are on the WDFW’s prohibited long and when laid for ward towards the eye, list. reaches the front of the eye. The caudal fin is slightly forked. (Wydoski and Whitney 1979; Origin and distribution. Becker 1983). During breeding season, males will be more brightly colored and the females History of invasiveness. will have darker more prominent vertical bands (Wydoski and Whitney 1979). The first introduction of pumpkinseed into the Pacific Northwest is believed to have occurred in the Willamette River of Oregon in Overview 1893 (Wydoski and Whitney 1979). The U.S. Pumpkinseed fish are a freshwater fish Fish and Wildlife Commission released in the family Centrarchidae. Pumpkinseed are largemouth bass and a small sunfish fry of native to the Great Lakes area, but have been which pumpkinseed was presumed to be globally introduced for sportfishing. In their included. Wide spread stocking has occurred in Figure 1: Native and Non-native Distribution through-out the United States (United States Geological Survey 2007). over 160 Washington lakes (Washington escaped into the wild. Pumpkinseed Department of Fish and Wildlife. 2005), for pan introductions and naturalizations continued to fish fisheries, promoting a juvenile pan fish occur through out Europe in 35 countries derby, (Sportsman Lake Stock Assessment including Czechoslovakia, Italy, Poland, Survey 2001) and for general sport fishing.( Switzerland, Hungary, Romania, the former Department of Fish and Wildlife. 2005). Sunfish Yugoslavia, The Netherlands, and Belgium. spread into British Columbia is most likely the (Raveret-Wattel 1900; Welcomme result of its natural spread from the Columbia 1981;Grimaldi 1972;Muus and Dahlstrøm 1968; River system (Crossman 1991). Outside of the Thienemann 1950; Nikolsky 1961;Looyen 1948; United States, pumpkinseeds were imported to Brouwer 1925; De Groot 1985) Pumpkinseeds Germany by Max Von dem Borne in an are also wide spread in the Iberian Peninsula experimental attempt to raise them in his (García-Berthou and Moreno-Amich 2000) and hatchery. In 1885 pumpkinseeds arrived in parts of Southern England (Künstler 1908). France and were subsequently released, or Current distribution in the Pacific Northwest Pumpkinseed are presently found in over 160 lakes in Washington state, 11 documented lakes in Idaho and 66 lakes in Oregon (Washington Department of Fish and Wildlife. 2005; Simpson and Wallace 1978; Lee et al. 1980; Lamp man 1946; Chapman 1942). It is also found in British Columbia in the Columbia River (Crossman 1991). Life-History and Basic Ecology Life Cycle Figure 2:. Growth rate curve compiled from pooled Life for a pumpkinseed starts off with a data and fitted with von Bertalanffy growth model 1mm diameter egg stuck to a small stick or rock for European and North American pumpkinseed (Copp et al. 2004). inside an under water nest. Hatch time is temperature dependant with a range of 47 hours macroinvertibrates to gastropods. This change at temperatures between 19.0-24.7° C and 3 has been correlated with rapid growth in their days at 27.8°C (Balon 1959). The larval stage native environment. Secondly, the European lasts 22 days. (Houde and Zastrow 1993). Young pumpkinseed shows an in increase in resource pumpkinseed leave their nest but remain near the allocation to reproduction, rather than growth. shallow breeding area (Becker 1983) and have They state that a higher reproductive effort been observed to travel in loose schools (Emery increases the chance of establishment in a novel 1973). Growth rates can vary widely depending environment. In their native range pumpkinseed on location. are sexually mature by 2 to 3 years of age, can In a study done by Copp et al. (2004), growth live to 12 years, but generally not beyond 6 rate and adult size was lower for introduced years (Wydoski and Whitney 1979). In their pumpkinseed in Europe than pumpkinseed in its introduced ranges, ages of sexual maturity vary. native range in North America (figure 2). They In Southern England, pumpkinseeds are not propose this is due to two factors. First, unlike found to be mature until almost 4 years (The the adult native pumpkinseed, the European Fisheries Society of the British Isles 2006.). In adult pumpkinseed have no dietary transition France, reproductive maturity was achieved in from the juvenile food preference of soft-bodies the summer after their first winter and the life span in this reservoir is 3years (Dembski et al. The dietary shift is not regularly seen in Europe. 2006). Both these exceptions were related to Lack of gastropods led to less trophic temperature difference from the native range. In segregation between adults and juveniles and France the adverse biotic condition of high water has been proposed as one mechanism to explain temperature resulted in high adult mortality and decreased growth, as well as diminished resulted in early, highly fecund reproduction, predatory pressure (Copp et al 2004) and when water was colder in southern England, Molluscivory is seen at Lake Banyoles on the development time was slowed. There is also the Iberian Peninsula. Endemic snails are consumed lack or absence of predators, in the non-native by adults as well as shrimp and insect larva. environment, which can result in delayed Juvenile fish fed on littoral microcrustaceans. maturation as a fish grows larger (Reznick and (Garcia-Berthou & Moreno-Amich, 2000). This Endler, 1982). has led to life history traits and morphology changes in native snails (DeWitt, 1998). Feeding Habits Negative impacts on the snails have been seen as In the native habitat, pumpkinseeds feed a potential problem (Garcia-Berthou & Moreno- on different species depending on their life Amich, 2000). stage. Juvenile pumpkinseed feed on soft-bodied The pumpkinseed is active during the day, but macroinvertibrates (Copp et al. 2004). Adult by dusk they move to the bottom to rest near pumpkinseeds are omnivorous and will feed on fallen logs or rocks and rest (Becker 1983). several prey species including rotifers, worms, During winter time, the pumpkinseed doesn’t insect larva and plant material. Unique to adult feed, and the stomach is shrunken and filled with pumpkinseeds in relationship to other sunfish is mucus. Once the water begins to warm, a its specialized large jaw musculature with large feeding response is initiated (Carlander 1977). molar like teeth that allows it to feed on snails (Becker 1983; Robinson et al. 2000). The shift Reproductive Strategies in food type with more emphasis on Pumpkinseeds are iteroparous, thus they molluscivory parallels sexual maturity, but is not spawn several times within their life span. evidence of a preference for snails, but just of Spawning in native regions occurs in early May their availability, the morphological structured to August (Becker 1983). Temperatures between jaw to bite through the shells, as well as an 11.5 and 14.0 C are needed to trigger male’s ontogenetic shift in food resource that allows gonad growth, and temperatures between 14.0 greater partitioning between the adults and the and 16.5 C are needed are need to initiate female juveniles (Garcia-Berthou and Moreno-Amich, gonad growth (Burns 1976). The larger males 2000). construct a nest which is a circular depression on the substrate of the warmer, shallow, littoral have two nests at the same time (Breder and zone. This is done by fanning the tale and Rosen 1966). removing large objects with their mouths Males guard the nest from potential threats, (Adams and Hankinson 1926). Once the nest is including sneaker males, because cannibalism built, males will defend their territory around the occurs in pumpkinseed fishes (Rios-Cardenas nest from about a 1 meter in diameter inwards. and Webster 2005). They also fan the eggs Defense of the nest includes nipping, chasing, which also results in higher survival rates but fanning out the opercula, and very rarely actual this parental care costs the males body mass as mouth to mouth fighting (Clark and Keenleyside they don’t leave the nest to feed (Rios-Cardenas 1967). Small, sexually mature males don’t make and Webster 2005), ultimately suffering high nests, rather these “sneaker” males insinuate mortality rates by the end of the season (Gross themselves into the spawn of the males who 1980).