Helminth parasites and epizoites in common dolphins (genus Delphinus) from coastal Peru and Ecuador

A twenty-five year old dataset of parasites in long-beaked and short-beaked common dolphins (Delphinus spp.), using fisheries as an opportunistic platform of access, registered seven species of helminths and one epizoite, being a unique dataset for the Southeast Pacific. Sampling was conducted in 1985-2000 at six fishing ports in Peru and Ecuador where cetaceans were landed from interactions with small-scale fisheries. From a total of 473 common dolphins examined, we identified helminths including three species of Trematoda: Nasitrema globicephalae, Pholeter gastrophilus, and Braunina cordiformis; three species of Nematoda, including Anisakis spp., Crassicauda spp., and Halocercus sp.; and two cestodes, Tetrabothrius forsteri and Clistobothrium delphini. No acanthocephalans were observed. No statistically significant sexual and ontogenetic variation in helminth prevalence was detected, after which samples were pooled. The highest prevalences in the long-beaked common dolphin (n = 440) were observed for N. globicephalae (87.9%, 29 infested/33 sampled) in cranial sinuses, Crassicauda sp1. (80%, 4/5) in mammary glands, followed by Cl. delphini (28.6%, 2/7) in the blubber, and P. gastrophilus (23%, 26/113) in the pyloric stomach. Although comparative testing was unfeasible due to minimal samples of short-beaked common dolphin (n = 33), several of the same helminth species were found; but not N. globicephalae nor B. cordiformis. No cyamids were encountered while pseudo-stalked barnacles Xenobalanus globicipitis were common. Although no new (global) helminth host records were revealed for common dolphins, this study presents a first checklist of parasites separately for the Southeast Pacific long-beaked and short-beaked common dolphins. Future work should include exhaustive laboratory-based necropsies, enhanced sampling of the short-beaked form, review data from recent parasite collections, focus on intermediate hosts and parasitic pathology, including potential human health impact from consumption of small cetaceans

Can Community-Based Ecotourism with the Amazon River dolphin contribute to its conservation in Brazil?

In Brazil, the Amazon River dolphin or boto (Inia geoffrensis) is considered a charismatic creature of the Amazonian culture and freshwater biodiversity, which attracts a lot of tourists searching for unique experiences with wildlife. Under several threats, boto’s population is declining and opportunities/alternatives to develop conservation actions are needed, advised, and urgent. This study aimed to investigate from local riverside perspective if the dolphin-watching Community-Based EcoTourism (CBET) is a good conservation alternative for boto. By applying semi-structured interviews and participant observation methods, we studied the perception of 68 riverside people from the Mamirauá Sustainable Development Reserve (MSDR), central Amazon. Some 88.3% of respondents considered the dolphin-watching tourism as an important conservation measure, since it helps in the dissemination of local knowledge about the species, restrains ‘outsider’ fishermen presence, and generates alternative income to communities. The same respondents understand as important the conservation of boto, and 68% said that keeping ecological relations between animal and environment helps in the conservation of its habitats. The economic benefits of dolphin-watching tourism in the MSDR were reported by 32.8% respondents. Community-based wildlife tourism is one of the widely used tools to promote species conservation and their habitats, when following good practices and promoting awareness, economic benefits, and scale up impacts. The results from this study provide information which may support strategies for the touristic management and conservation of botos in the Amazon

The potential of passive acoustic monitoring for the study of ecological interactions among freshwater Amazonian dolphins and fishes

The acoustic behavior of Amazonian aquatic fauna and the importance of its soundscape are poorly understood. Sounds produced by wild river dolphins (Amazon River dolphin, Inia geoffrensis, and tucuxi, Sotalia fluviatilis) and those of unidentified fishes were recorded from a drifting boat on six different days (8.5 h duration) in July 2012, in the Pacaya-Samiria National Reserve of Peru. Unidentified sounds of fishes were dominated by four broad types: pulsed stridulation, long stridulation, long pulse, and short pulse. Dominant sounds produced by dolphins included echolocation click trains, burst-pulses, whistles, and bubble bursts. Soniferous activity was quantified as total sound duration per 10 s of recording and compared between dolphins and fishes for each sound type and all types combined. Soniferous activity was highly variable among days, with echolocation click trains (7.7 s min-1) and pulsed stridulation (0.33 s min-1) being the dominant components. Soniferous activity of the dolphins and fishes was correlated (Spearman r = 0.49, P < 0.001). However, whether the correlation resulted from predator-prey interactions or other spatial factors could not be determined. Although preliminary in nature, this study is the first examination of the soniferous activity of both river dolphins and fishes in the Amazon and suggests passive acoustic monitoring has the potential to provide unique insight into ecological interactions in the system