5th International Symposium-Workshop on Frugivores and Seed Dispersal (1985-2010)

FSD 2010 - Characids

FSD2010

IYB2010

www.cbd.int/2010

Characids

Pacu, and other seed-dispersing Characid fishes

According to literature, fishes are believed to be the first vertebrate seed dispersers, yet little research has examined this phenomenon. Ihthyochory has been assumed to be an archaic form of dispersal within primitive angiosperms that has been maintained in inundated tropical regions. The high frequency of ichthyochory is associated with nutrient-poor Amazonian waters, where fish depend substantially on allochthonous material such as seeds and fruits which fall into the water. The homogeneity of the inundated vegetation in Amazonia may be the result of migratory fish dispersing diaspores.

Among them, Characid fishes (Photo : Pacu at Montpellier zoo. (c) PM Forget) are considered to be omnivores; for instance, the frequency of occurrence of items of animal origin was found to be equivalent to that of vegetal origin in the fish Brycon opalinus. These Characid fishes consume fruits and seeds from floodplain forests during the annual flood season, potentially serving as important seed dispersers and predators.

Frugivory and seed dispersal has been especially studied in the piraputanga fish (Brycon hilarii) in the Formoso River, Bonito, western Brazil.  The stomach contents of 87 fishes consisted of 24% animal prey (arthropods, snails, and vertebrates), 31% seeds/fruits and 45% other plant material (algae/macrophytes/leaves/flowers); fishes were considered as seed dispersers for eight out of 12 consumed plant species.

In the Amazon, the diet of the frugivorous fish, Colossoma macropomum and Piaractus brachypomus comprised 78-98 percent fruits, largely dominated by a few species. Diets included fruits of 27 woody angiosperms and four herbaceous species from 26 families, indicating the importance of forest and Montrichardia arborescens habitat during peak flood. In a varzea forest of the Rio Madeira in Humaita, Amazonas, 16 out of 33 plant species had seeds or fruits regularly dispersed by fish, and in 17 species the seeds were usually destroyed when eaten.

The role of characid fishes as seed dispersers has also been evaluated in different riverine systems in Central and South America. For instance, authors have demonstrated that seeds of the fig tree Ficus insipida are dispersed by both bats and fishes in riparian habitats at La Selva Selva Biological Station in Costa Rica. In Pantanal, Southern Brazil, the most important food item in the diet of the pacu (Piaracrus mesopotamicus) in the wet season is fruits of the palm Bactris glaucescens which intact seeds were found in large number of the gut of a majority of fishes collected.

Because fruit-eating fishes are often preferred by commercial fisheries, over fishing in freshwater ecosystems as well as deleterious human impacts on aquatic ecosystems worldwide might have major impacts on the dispersal system of fish-dependent plants with unknown ecological consequences for both plant and animal communities.

(Photo: Carrefour in Campo Grande, MS, Brazil. (c) PM Forget)

 

References

Characid (wikipedia)

Pacu (wikipedia)

Mongabay.com (Pacu)

 

Literature

Anderson, J.T., Rojas, J.S., Flecker, A.S. 2009. High-quality seed dispersal by fruit-eating fishes in Amazonian floodplain habitats. Oecologia 161 279-290 .

Banack, S.A., Horn, M.H., Gawlicka, A. 2002. Disperser- vs. establishment-limited distribution of a riparian fig tree (Ficus insipida) in a Costa Rican tropical rain forest. Biotropica 34, 232-243. Abstract

Correa SB, Winemiller KO, Lopez-Fernandez H, and Galetti, M. 2007. Evolutionary perspectives on seed consumption and dispersal by fishes. Bioscience 57, 748-756.

Galetti, M., Donatti, C.I., Pizo, M.A., and Giaomini, H.C. 2008. Big fish are the best: seed dispersal of Bactris glaucescens by the pacu fish (Piaractus mesopotamicus) in the Pantanal, Brazil. Biotropica 40, 386-389. Abstract

Gomiero, L.M., Manzatto, A.G., and Braga, F.M.S. 2008. The role of riverine forests for food supply for the omnivorous fish Brycon opalinus Cuvier, 1819 (Characidae) in the Serra do Mar, Southeast Brazil. Brazilian Journal of Biology 68, 321-328.

Gottsberger, G. 1978. Seed dispersal by fish in the inundated regions of Humaita, Amazonia. Biotropica 10, 170–183.

Horn, M.H. 1997. Evidence for dispersal of fig seeds by the fruit-eating characid fish Brycon guatemalensis Regan in a Costa Rican tropical rain forest. Oecologia 109, 259-264. Abstract

Lucas,C.M. 2008. Within flood season variation in fruit consumption and seed dispersal by two characin fishes of the Amazon. Biotropica 40, 581-589. Abstract

Reys, P, Sabino, J. and Galetti, M. 2009. Frugivory by the fish Brycon hilarii (Characidae) in western Brazil. Acta Oecologica 35, 136-141. Abstract

Other selected references about seed dispersal by fishes in the temperates

Pollux, B.J.A., De Jong, M., Steegh, A., Ouborg, N.J., Van Groenendael, J.M. & Klaassen, M. 2006. The effect of seed morphology on the dispersal of aquatic macrophytes by the common carp (Cyprinus carpio). Freshwater Biology, 51, 2063–2071.

Pollux, B.J.A., Santamaría, L. & Ouborg, N.J. 2005. Differences in endozoochorous dispersal between aquatic plant species, with reference to plant population persistence in rivers. Freshwater Biology 50, 232–242.

Pollux, B.J.A., Ouborg, N.J., Van Groenendael, J. M., and Klassen, M. 2007. Consequences of intraspecific seed-size variation in Sparganium emersum for dispersal by fish. Functional Ecology 21, 1084-1091. Abstract