SEASONAL ECOLOGY OF INIA IN THREE RIVER BASINS OF SOUTH AMERICA (ORINOCO,AMAZON, AND UPPER MADEIRA) - Biology, Evolution and Conservation of River Dolphins Within South America and Asia - page 49

also not observed directly, would seem more likely to occur during extreme low water
seasons, when dolphins and vessels are navigating the same restricted waterways. Fishing and
tourism activities are primarily vessel-based, and peak during the low water season. In
addition to the potential threats from strikes, boat motors produce noise, which may cause
disruption of dolphin behavior and habitat use. The two instances of presumed intra-specific
aggression were observed during the low water season, and may have been sexual in nature
(McGuire, 1995; Aliaga-Rossel, 2000).
Although much of the area of distribution of Inia is unprotected, river dolphins do occur
in protected areas of countries throughout their range (e.g., Santos Luzardo National Park in
Venezuela, Pacaya-Samiria National Reserve in Peru, Mamirauá Reserve in Brazil, Noel
Kempff Mercado National Park in Bolivia). Better understanding of the seasonal ecology of
Inia could contribute to the conservation of this vulnerable species, primarily by enhancing
reserve and fisheries management. Consideration of restrictions on vessel traffic and certain
fishing practices in critical seasons and habitats may be warranted in some areas.

A CKNOWLEDGMENTS

We thank our families and the following: the Willie May Harris Fellowship, the Mendon
B. Krischer Scholarship, Fundación Fluvial de los Llanos, Laguna Larga Lodge, the Cinaruco
Fishing Club, Kirk Winemiller, Bernd Würsig, David Jepsen, Don Taphorn, the Garcia
family, the volunteers and staff of Earthwatch, Elderhostel and the Oceanic Society, the crew
of the Miron Lento and Delfín, INRENA, ProNaturaleza, the Tenazoa family, Elizabeth
Zúñiga, Gerónimo Vega Quevare, the Virtual Explorers, Dulcie Powell, Fremen Tours,
Ramiro Cuellar and family, Healy Hamilton, the Kramarae/Kramer family, Michael Link and
LGL Alaska, the American Cetacean Society, and Cetacean Society International. Research
was conducted under the following permits in Peru: INRENA-DGANPFS-DNAP #53-97,
#27-99, and #02-S/C2000. For Venezuela, one permit was needed (SARPA #0493) while no
permits were necessary for Bolivia (unprotected area).

R EFERENCES

[1]

Aliaga-Rossel, E. (2000). Distribución y abundancia del delfín de río, bufeo (Inia
geoffrensis) en el río Tijamuchi, Beni, Bolivia. Lic. Thesis, La Paz, Bolivia:
Universidad Mayor de San Andres.

[2] Aliaga-Rossel, E. (2002). Distribution and abundance of the river dolphin (Inia

geoffrensis) in the Tijamuchu River, Beni, Bolivia. Aquatic Mammals , 28, 312-23.

[3] Aliaga- Rossel, E., Mc Guire T. L. & Hamilton, H. (2006). Distribution and encounter

rates of the river dolphin (Inia geoffrensis boliviensis) in the central Bolivian Amazon.
Journal of Cetacean Research and Management, 8, 87-92.

[4] Banguera-Hinestroza, E., Cardenas, H., Ruiz-García, M., Marmontel, M., Gaitán, E.,

Vásquez, R. & García-Vallejo, F. (2002). Molecular identification of evolutionarily
significant units in the Amazon River Dolphin Inia sp. (Cetacea: Iniidae). Journal of
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