[en] This final degree thesis (field research), describes the daily rhythms of the bottlenose dolphin, Tursiops truncatus, in the waters of the Gulf of Ártabro (A Coruña, NW Spain). The study was carried out by means of sightings from cliffs located at 7 points along the coast of Dexo. In this way, we obtained information on their diurnal activity, which peaked in the afternoon. In terms of population size, a maximum of 30 individuals were observed, generally appearing divided into subgroups. The most frequently sighted group was that of 10 to 15 individuals, followed by the smallest number (between 1 and 5 individuals). On the other hand, statistically significant differences between seasons were obtained: bottlenose dolphins vary their activity by time slot according to the time of the year they are in, bringing it forward in autumn/winter compared to spring. In terms of behaviour, it was divided into 3 patterns: movement, feeding and socialisation/play. The results indicate that Tursiops truncatus mainly move around in the morning, while the following time slots are mainly devoted to foraging. Finally, after hunting and feeding, in the afternoon (before sunset) there is a high percentage of socialising and playing. The route followed was also analysed in terms of movement: westwards in the early morning and early afternoon (probably for hunting) and eastwards at dusk (the interior of the estuary could be a quieter and safer place for the young from dusk onwards). In addition to this, analysing the effects of other parameters, a higher number of sightings were obtained in autumn and winter than in spring, with non-sunny days, strong swell and low (rising) tide. On the other hand, the presence of boats seems to have a negative effect on these frequencies. However, the results obtained were statistically non-significant.

[gl] En este traballo de fin de grao (investigación de campo) descríbense os ritmos diarios do arroaz, Tursiops truncatus, nas augas do Golfo Ártabro (A Coruña, NO España). O estudo levouse a cabo mediante a realización de avistamentos dende os cantís situados en 7 puntos da costa de Dexo. Desta forma, obtivemos información sobre a súa actividade diurna, que mostrou un pico pola tarde. En canto ao tamaño da poboación, foron observados un máximo de 30 individuos, aparecendo, polo xeral, divididos en subgrupos. O grupo visualizado máis frecuentemente foi o de 10 a 15 individuos, seguido polo de menor número (entre 1 e 5 individuos). Por outra banda, obtivéronse diferencias estadísticamente significativas entre estacións: os arroaces varían a súa actividade por franxa horaria en función do momento do ano no que se atopan, adiantándoa no outono/inverno frente á primavera. No relativo ao comportamento, dividiuse en 3 patróns: desprazamento, alimentación e socialización/xogo. Así, os resultados indican que Tursiops truncatus se despraza, principalmente, pola mañá, mentres que as seguintes franxas horarias están adicadas, fundamentalmente, á alimentación. Finalmente, tras cazar e alimentarse, pola tarde (antes do atardecer) hai unha alta porcentaxe de socialización e xogo. Atendendo soamente ao desprazamento, tamén se analizou a ruta seguida: direción Oeste nas primeiras horas da mañá e ao comezar a tarde (probablemente para cazar) e direción Este ao atardecer (o interior da ría podería ser un lugar máis tranquilo e seguro para as crías a partir do anoitecer). Ademais disto, analizando os efectos doutros parámetros, obtívose un maior número de avistamentos en outono e inverno que en primavera, con días non soleados, ondada forte e marea baixa (subindo). Pola súa banda, a presenza de barcos parece afectar negativamente a ditas frecuencias. Porén, os resultados obtidos foron estadísticamente non significativos.