-The whalesucker Remora australis (Echeneidae) is an oceanic diskfish found attached to cetaceans only and its habits are therefore poorly known. At the Fernando de Noronha Archipelago, off North-eastern Brazil, spinner dolphins Stenella longirostris (Delphinidae) regularly congregate in large groups in a shallow bay, which allows for underwater observations of their behaviour and their fish associates. In the course of a broader study of this elusive diskfish, we had the opportunity to made multiple records of two whalesucker couples (three of the fish naturally marked) attached to the same individual dolphin in two different years, over periods of 47 and 87 days respectively. In all the sightings the whalesucker individuals of a couple were recorded side-by-side and positioned on their host's belly. We surmise that at least one of the couples was a reproductive pair, as the belly of the larger fish was noticeably swollen in the last sighting, and the bulge on its belly was bilateral and extended almost uniformly to the vent, a strong indication of fully mature gonads. Moreover, its size matched those of the mature females of this diskfish species. To our knowledge, this is the first time that attachment fidelity of the whalesucker to any cetacean host is documented in the wild. We hypothesize that attachment fidelity to the same individual host increases the whalesucker's chance to mate, and suggest further that the highly social nature of the spinner dolphins facilitates encounters between potential mating partners. Our study indicates that host fidelity possibly is not an uncommon feature of the whalesucker behaviour, albeit difficult to recognise. In one of the above recorded whalesuckers the natural marking was a crescentic scar characteristic of the wounds inflicted by the cookiecutter Isistius brasiliensis (Dalatiidae), a first record of the attack of this shark to any diskfish species.Key words: Fish-cetacean association, host attachment fidelity, mate finding, Echeneidae, Delphinidae,Southwestern Atlantic Resumo -A rêmora-das-baleias Remora australis (Echeneidae) é um peixe-pegador oceânico que vive agarrada somente a cetáceos, sendo seus hábitos mal conhecidos devido a esta característica. No Arquipélago de Fernando de Noronha, ao largo do Nordeste do Brasil, os golfinhos-rotadores Stenella longirostris (Delphinidae) congregam-se regularmente em grandes grupos numa baía rasa, o que permite o estudo subaquático de seu comportamento e dos peixes associados. Ao longo de um estudo amplo deste peixe-pegador pouco conhecido, tivemos a oportunidade de fazer registros múltiplos de dois pares de rêmoras (três delas com marcas naturais), agarradas ao mesmo golfinho em dois anos distintos, por períodos de 47 e 87 dias, respectivamente. Em todas as observações, os indivíduos de cada par de rêmoras foram registrados um ao lado do outro e posicionados no ventre do hospedeiro. Supomos que pelo menos um dos pares fosse um casal reprodutivo, pois o ventre do indivíduo maior apresentava saliência bilateral bem...

An update is presented for fish species associated with spinner dolphins at Fernando de Noronha Archipelago, tropical Western Atlantic, providing a general view of their diversity. The associates are mostly reef-dwelling fishes that feed on the dolphin wastes. Twelve species are habitual or occasional plankton-eaters and two species are herbivores that occasionally forage on floating pieces of algae. One species is a strict carnivore, one species is a hitchhiker that forages on a variety of foods including parasites and dead tissue from the dolphins, and one species is a carnivore that joins the dolphin groups to forage on schools of small fishes or squids. We predict that the list of fish associated with spinner dolphins will expand mostly with addition of habitual or occasional plankton-eaters.Uma atualização é apresentada sobre as espécies de peixes associados a golfinhos-rotadores no Arquipélago de Fernando de Noronha, Atlântico Ocidental, fornecendo uma visão geral sobre sua diversidade. Os peixes associados são principalmente habitantes recifais que se alimentam de dejetos dos golfinhos. Doze espécies são planctófagas habituais ou ocasionais e duas são herbívoras que se alimentam ocasionalmente de algas à deriva. Uma espécie é carnívora estrita, uma vive fixada aos golfinhos e seu alimento é variado, incluindo parasitos e tecido morto dos golfinhos, e uma é carnívora que se junta aos grupos de golfinhos durante a caça a peixes e lulas. Prevemos que a lista de peixes associados a golfinhos-rotadores seja expandida principalmente com adição de planctófagos habituais ou ocasionais.

At Fernando de Noronha Archipelago in the tropical West Atlantic, spinner dolphins (Stenella longirostris) regularly congregate in a shallow bay where they engage in resting, social, and eliminative behaviours. The dolphins' congregation allowed underwater observations from close quarters of the whalesucker (Remora australis), an open-water fish species found attached to cetaceans only and whose habits remain thus poorly known. Whalesuckers were recorded year-round on the Fernando de Noronha spinners. Estimated size-range of whalesuckers in 211 records was 4-52 cm in total length (TL). Number of fish per dolphin was 1-3, the most frequently recorded attachment place being the host's belly (78.2%). Ratio of whalesuckers to spinner dolphins was 1-1.8 (mean ¼ 1.32; SD + 0.47) over one year. Juvenile, recently recruited individuals (less than 10 cm TL) were recorded year-round. Whalesuckers occasionally fed on dolphin faeces, and thus would also be able to feed on plankton while riding the spinners. Cleaning of the host's wounds was recorded twice during the study. Adult fish side by side or close to each other were regarded as an indication of reproductive pairs. The association of the whalesuckers with a middle-sized, fast and social cetacean likely provided this remora with ride, food, increased opportunity for reproduction and mating place, and perhaps protection from fast predators such as sharks, tuna, and larger dolphins.

No abstract

Activities displayed by animals are usually cyclic, and fluctuations in behavioural repertoires can be observed on a daily or seasonal timescale. The present study describes daily and seasonal variations in the aerial events – such as leaps, spins and slaps with body parts – by spinner dolphins in Baía dos Golfinhos, Fernando de Noronha Marine National Park, in Brazil. To measure aerial events by dolphins, we compiled and analysed data collected from January 2006 to December 2010. A total of 113,027 aerial events were recorded during 1431 days of land-based daytime observations. Our results show that the frequency of aerial events was positively correlated with the number of dolphins in the bay. The relative frequency of aerial events was higher in the rainy season, when compared with the dry season. Aerial activities also varied throughout the day, with dolphins being more active in the morning, specifically from 8:00 a.m. to 8:59 a.m., regardless of the season.

We present an overview of predator-prey and other trophic relationships of spinner dolphins (Stenella longirostris) around Fernando de Noronha Archipelago, off northeastern Brazil, with use of original data and a brief review of data published elsewhere. Records were made while snorkelling among the dolphins in daytime. Individual fish pursuit and coordinated school herding were the two hunting tactics recorded. Three small prey types (oceanic squids, fishes, and prawns) were recovered from vomits collected in situ and from stomachs of two stranded dolphins. In their turn, spinners were preyed on by the cookiecutter sharks (Dalatiidae) as evidenced by round and crater-like wounds and circular scars. Additionally, the dolphins were preyed on by large sharks (Lamnidae, Carcharhinidae), as evidenced by crescent-shaped wounds and scars. Unidentified fishes bit fin pieces, as evidenced by variably-shaped marks. On the other hand, dolphins' particulate faeces, vomits and live roundworms were eaten by plankton-feeding fishes. Thus, the trophic role of the spinner dolphins of Fernando de Noronha may be summarised as that of : 1) a predator of small oceanic squids, fishes, and prawns; 2) a prey for the small, piece-eating cookiecutter sharks and other unidentified fishes; 3) a prey for large sharks able to kill a dolphin; and 4) a particulate food supplier for plankton-eating fishes.

In Brazil, the whale watching is practiced with different species, such as whales, dolphins, and porpoises. This activity facilitates the growth of the economic activities of communities in many regions of the country, and it may be a tool for awareness about the marine preservation and conservation. Moreover, the whale or dolphin watching also impacts native species. The Fernando de Noronha Archipelago (FN) is a worldwide watching tourism site due to the time of the development of activities and the ease to watch cetaceans, mainly the spinner dolphin (Stenella longirostris). The aim of this study was to characterize the dolphin watching in FN. Additionally, we will investigate the applicability of the "Tourism Area Life Cycle" (TALC) approach for a tourism activity, identifying the main events or stages that promoted significant changes throughout the history of the activity in the archipelago. We observed that both land based and boatbased (boat trips) are available in FN. The boat trips are more common and involve the triple of tourists than landbased watching. However, the last provides more informative and educational component. The history of dolphin watching tourism in FN was developed concomitantly with the tourism destination of the archipelago as a whole. Through TALC analysis, dolphin watching in FN had its development together with the destination development and, currently, both areas present stagnation stage indicators. In addition, the landbased watching, for being less impacting and more educative, has potential to increase the visitation.