note, Isabella et al. report a possible population recovery of giant otters in the Tauramena municipality of Colombia.Their surveys identify five unique family groups in a region where the species was believed to have been extirpated due to illegal hunting and the pelt trade.Finally, we include In Memoriam tributes by Chapham et al. and May-Collado et al., honoring the late Oswaldo Ravelo and Eric Ramos, respectively.Both individuals made significant contributions to marine mammal research, particularly within Latin America and will be greatly missed.Eric was a member of our Editorial Board and a dear friend to many of us.The LAJAM editorial team continues to undergo changes.In our previous issue, we announced that Dr. Eduardo Morteo was stepping into the role of Managing Editor.Unfortunately, that transition did not work out, and Dr. Daniel Gonzalez-Socoloske has resumed the role for the time being.We are also in the process of expanding our team of Associate Editors.

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 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.

The giant otter (Pteronura brasiliensis) is endemic to South America, and in Colombia it is distributed in the Amazon and Orinoquia regions. It inhabits rivers, streams, and lagoons, but prefers the latter two in response to resource availability depending on the season. Giant otters are endangered in Colombia, and aspects of their natural history are still unknown in much of their geographic range. Our research aim is to generate information focused on relative abundance, habitat use, and distribution of the giant otter in an area of Colombia where it was thought to be extirpated. The distribution was evaluated with spatial distribution modeling (SDM) and habitat use using the Wallace 2.0.4 package for the department of Casanare in northeastern Colombia. To assess the population status and abundance in the municipality of Tauramena, 30 transects were surveyed in the Tua River and the Piñalito and El Huesero streams in 2021 and 2022. In general, the distribution models highlighted the importance of precipitation, temperature, and forests for the occurrence of this species. In Tauramena, five family groups were detected, which were composed of an average of 4.83 ± SD 3.16 individuals per group and a relative abundance of 1.03 ind./km. These are positive results for giant otters, as they indicate signs of population recovery of a species previously thought to have been extirpated from this region because of hunting and illegal pelt trade. Even though Tauramena is an area with high levels of anthropic disturbances, giant otters are showing signs of adaptability and plasticity, which provide important conservation opportunities. It is expected that this work will become the first step for the generation of additional information on diet, behavior, and population structure that can inform management plans for the giant otter in Colombia.

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.