Colossoma macropomum (Cuvier, 1816)

Angulo, Arturo, 2021, New records and range extensions to the Costa Rican freshwater fish fauna, with an updated checklist, Zootaxa 5083 (1), pp. 1-72 : 8

3) * Colossoma macropomum (Cuvier, 1816) ;

Serrasalmidae . Blackfin Pacu, Cachama; Colosomo, Cachama Negra, Tambaquí, Pacú ( Figs. 2D–E ).

Diagnosis: This exotic species can be easily identified from the species of the order occurring in the freshwaters of the country by the presence of rays in the adipose fin (vs. no rays in the adipose fin in the other Characiformes ), body shape (robust and oval, with the predorsal profile strongly rounded to concave), color (usually coppery gold in the upper half, dark black in the lower and posterior half and pinkish or reddish in the lower and anterior half) and size (reaching about 1 m total length).

Basis of the record: Several captures have been recently (2017–2021) reported by artisanal and sport anglers in the lower and middle portions (1– 40 m.a.s.l.) of the Tempisque and Bebedero rivers in the north Pacific region of the country. Additional verified records came from the San Carlos River in the north (Atlantic) region of the country.

Remarks: This species was introduced by government agencies and private entities in an attempt to strengthen aquaculture activities and to control the populations of the invasive apple snail ( Pomacea sp. ). This species is also used in the aquarium trade.

Figures

FIG. 2. New country records. (A) Amphilophus labiatus, specimen captured in the Río San Juan, San Carlos, Alajuela (ca 10.89057, -84.26540), at ca 26 m.a.s.l., in November 2020, by an anonymous angler. (B) Amphilophus labiatus, specimen captured in the Río Sapoá, La Cruz, Guanacaste (11.21815, -85.60819), at 8 m.a.s.l., on January 19, 1967, by William Bussing and Myrna López (UCR 0122-014). (C) Anchovia clupeoides, specimen captured in the Río Pacuare, near the mouth of the river, Siquirres, Limón (10.21952, -83.28254), at 8 m.a.s.l., on November 17, 2004, by Jorge Picado (UCR 2840-005). (D) Colossoma macropomum, specimen captured in the Río Bebedero, Portones de Taboga, Bebedero, Cañas, Guanacaste, Costa Rica (10.36978, -85.19772), at 10 m.a.s.l., on March 27, 2020, by Javier Blandon. (E) Colossoma macropomum, specimen captured in the Río Bebedero, Altamira, Cañas, Guanacaste, Costa Rica (10.35378, -85.20408), at 18 m.a.s.l., on April 30, 2021, by Agustin Guzman. (F) Gobioides peruanus being depredated by the Bare-throated Tiger Heron (Trigrisoma mexicanum Swainson, 1834), photo captured in the Quebrada Bomba Vieja (Barranca river basin), near the mouth of the Río Barranca, El Roble, Puntarenas (9.96228, -84.73493), at 6 m.a.s.l., on January 6, 2021, by Beto Guido Méndez (Bird watcher guide/Naturalist). (G) Hypostomus cf. niceforoi, specimens captured in the Humedal Caño Negro, Los Chiles, Alajuela (ca 10.89081, -84.79415), at ca 33 m.a.s.l., on May 11-16, 2016, by Didiher Chacón-Chaverri. (H) Lutjanus purpureus, specimen captured in the Quebrada Hone Creek/Río Carbón, Talamanca, Limón (9.67153, -82.79047), at 12 m.a.s.l., on October 6, 2007, by Maribel Mafla et al. (UCR 2751-001). (I) Lutjanus purpureus, specimen captured in the Río Moín, at the Puerto Fluvial JAPDEVA, Limón (09.99745, -83.08077), at 7 m.a.s.l., on December 14, 2006, by Karina Rodríguez (UCR 2761-003).