Luiz Cláudio Pinto de Sá Alves

Conflicts between river dolphins (Cetacea: Odontoceti) and fisheries in the Central Amazon: a path toward tragedy?

Dolphin interactions with fishermen have increased significantly and pose potential risks to the boto, Inia geoffrensis (Blainville, 1817), and the tucuxi, Sotalia fluviatilis (Gervais & Deville, 1853). The main objective of the present paper was to describe the existing conflicts between river dolphins and fishermen in the municipality of Manacapuru region. Sixteen fishermen were interviewed in Manacapuru, state of Amazonas, Brazil who described a situation of ongoing conflict that may be unsustainable. Two merchants from Manacapuru made unconfirmed reports on a boto carcass trade. Data collection for this study occurred between April 20th and April 25th, 2009, but the first author had been conducting research on river dolphins and fisheries in Manacapuru and nearby cities since the beginning of 2008, in order to gain the trust of the fishermen interviewed. The hunting and deliberate killing of the species is probably more threatening to botos than their incidental capture in fishing gears in the Manacapuru region. This practice may result from the fact that dolphins are prone to damaging fishing equipment, and stealing (and possibly damaging) fish from the nets. They are portrayed negatively in numerous myths and superstitions of traditional Amazonian folklore, making them extremely undesired or even hated, seen as pests, and used in the piracatinga, Calophysus macropterus (Lichtenstein, 1819) fishery as bait. For tucuxis, incidental capture still represents the major threat to their conservation in the region evaluated here.

Perception of local inhabitants regarding the socioeconomic impact of tourism focused on provisioning wild dolphins in Novo Airão, Central Amazon, Brazil

Botos (Inia geoffrensis) are currently provisioned for use in tourist attractions in five sites in the Brazilian Amazon. Despite the known negative effects associated with human-wild dolphin interactions, this activity has been regulated and licensed in the Anavilhanas National Park in Novo Airão, Amazonas State, Brazil. We present an updated evaluation of the perception of the local community concerning the possible socioeconomic impacts of this tourism in Novo Airão. In April 2011, 45 interviews were conducted with inhabitants. A small segment of Novo Airão perceives currently itself as being economically dependent on the botos feeding tourism. Despite that, the economic benefits of this controversial activity apparently are not shared among most inhabitants, and botos feeding tourism is perceived as generating diverse negative effects. We conclude that if the activity was banned or modified into a less impacting tourist activity, this action would probably not majorly affect the lives of the general population.

Resource defence and dominance hierarchy in the boto (Inia geoffrensis) during a provisioning program

Aggression is often utilised in intraspecific competition to establish and maintain dominance hierarchies in social mammals. Here, we determine if aggressiveness in conditioned botos (Inia geoffrensis) during interactions with humans under provisioning is influenced by the presence or absence of food rewards and if provisioning leads to the establishment of a dominance hierarchy among these generally solitary animals. Mean values of bites among the botos for sessions in which food rewards were delivered were significantly higher than sessions in which no food reward was delivered. No significant difference exists between the mean number of bites per individual during feeding sessions, but the mean number of bites increased significantly with time when animals were not fed. Supplant behaviours were used as a non-harming alternative to bites. The botos’ provisioning is a case of instrumental conditioning, in which the conditioned botos expect to receive food from tourists, increasing competition among the animals when they are not fed. The provisioned botos exhibited an almost linear dominance hierarchy. Bites and supplant behaviours were used more frequently by dominant botos to prevent subordinates from obtaining food provisions. Interactions brought about by provisioning are likely to be harmful to the botos and potentially dangerous to humans.

Clymene dolphin (Stenella clymene) whistles in the Southwest Atlantic Ocean

The Clymene dolphin despite being endemic for the Atlantic Ocean continues to be the least known species in the genus Stenella without available information on their vocal repertoire in Brazilian waters. Data were obtained during mitigation and monitoring work required by IBAMA under the federal environmental licensing as conditions of the license 108/16 for the 3D seismic survey in Para/Maranhao Sedimentary Basin process 02022.000015/2014. The species record was performed onboard the vessel Polarcus Alima with a Mseis (Night Hawk III) four-element towed array passing signals to a digital M-Audio, recording at 96 kHz/16bits. During visual and acoustic monitoring with the air-guns off, a group of approximate 80 dolphins were sighted and recorded on May 8th, 2016 (00˚38’00” N, 44˚45’25” O) at 3,425 m depth. The wav-files were analyzed through the spectrogram configured as DFT 2048 samples, 70% overlap and Hamming window of 1024 points generated by software Raven Pro 1.5. The results of 14 min recording allo...