Peale's dolphins are small odontocetes living in the south Cone of America. As a coastal species, they could be threatened by the growing use of industrial and comercial harbors in the Patagonia region. To the date, their behavior, use of habitat and acoustic productions are still very little known. We report the coupling of visual and acoustic monitoring of a population of Peale's dolphins in the Magellan Strait. A comparison of visual monitoring and data from several acoustic devices (three C-POD click loggers and HighBlue, a full wave recording device) is presented, assessing the feasibility of long term monitoring through acoustic recording. Finally, acoustic productions of this group of Peale's dolphins are compared to other groups of Peale's dolphins and other narrow band high frequency (NBHF) odontocetes of the region.

Ship strikes are a worldwide threat to large whales as a major cause of mortality and injury. In the Southeast Pacific, this has been poorly studied. In the last decade, an increase in ship strikes has been observed off Chile. This study assesses ship strike mortality in large whales off Chile using data on fatal strandings from the past 52 years, (1972-2023) and vessel traffic patterns. In 63 out of 226 strandings (28 %), ship strike was the direct or probable cause of mortality, i.e. the primary cause of non-natural death in whales. Fin whales (B. physalus) suffered highest total ship strikes (n = 23; 37%), followed by humpback (M. novaeangliae) (n =13; 21 %), blue whales (B. musculus) (n = 7; 11 %), sei (B. borealis) and sperm whales (P. macrocephalus) (n = 6; 10 %). Ship strikes were highest in the Regions of Valparaiso, Coquimbo, Atacama and Antofagasta (Central-Northern Chile), Los Lagos, Aysen and Magallanes (Southern Chile). Since 2013, when necropsies began to be systematically performed, an average of 5 individuals/year have been killed by ships, mostly between January and May. We review all ship strike studies globally and compare rates in Chile with those elsewhere. Based on data between 2013 and 2023, Chile is the country with the highest ship strike mortality globally; considering the entire time series since 1972, Chile ranks number six worldwide. We identify major knowledge gaps and recommend policy measures, including establishing High-Risk Areas and the implementation of shipping lanes modifications and vessel speed restrictions.

The study of ecological connectivity is a global priority due to the important role it plays in the conservation of diversity. However, few studies in this context have focused on marine benthic ecosystems. To address this issue, the present work determines the ecological connectivity between two sub-Antarctic macrobenthic assemblages through assessment of the α-, β-, and functional diversity indices. Samples were collected using a van Veen grab at stations located in Bahia Inútil and Seno Almirantazgo. The ecological analysis was based on a total of 113 invertebrate taxa. The mean abundance values were lower in Bahia Inútil (888.9 ± 26.8 ind m−2) than in Seno Almirantazgo (1358.6 ± 43.4 ind m−2). While the mean α-diversity values showed significant differences between assemblages, β- and functional diversity indices presented no significant differences. These results indicate that, despite the distance (56 km) separating the two basins from each other, there is a high degree of connectivity at the functional level between the assemblages due to the high number of shared species and their functional traits. The species most responsible for this observation were the polychaetes Capitela capitata and Aricidia (Acmira) finitima, as well as the bivalves Nucula pisum and Yoldiella sp. 1. In terms of functional biodiversity, species characterized as omnivorous and with lecithotrophic larval development were mostly responsible for connectivity between assemblages. These results suggest the importance of including β- and functional diversity indices as criteria in the future planning of marine protected areas for the maintenance of marine ecosystem integrity.

The Chilean Patagonia is characterized by extensive protected areas that encompass most of the region. Mammals are often among the priorities for these protected areas either as conservation targets (e.g., threatened species) or as threats (e.g., invasive species). Camera traps offer a cost-effective alternative to monitor these species, however baseline studies are scarce in the region. Therefore, our objective was to provide an assessment of camera-trapping detection rates for mammals that are present in protected areas of Magallanes, Chilean Patagonia. Between 2015 and 2022 we installed 278 camera traps (9,936 trap-days), distributed in seven protected areas. For each protected area, we calculated the detection rates and proportion of camera traps that detected each species. We recorded 18 mammalian species, including ten native, four domestic, and four invasive species. The culpeo fox (Lycalopex culpaeus) was the most frequently detected species, followed by invasive European hare (Lepus europaeus) and puma (Puma concolor). Endangered species like the huemul (Hippocamelus bisulcus) and southern river otter (Lontra provocax) were detected infrequently, whereas beaver (Castor canadensis) and American mink (Neogale when species of interest are associated with specific features of the landscape (e.g., otters and water), other designs are needed. Based on our findings, we provide recommendations for the design of camera-trapping monitoring plans in protected areas.

There are different ecotypes of killer whales ( Orcinus orca ) worldwide; type D killer whales are the least known. These killer whales have a globose head, an extremely small post-ocular patch and a falcate dorsal fin. We report the first stranding event of type D killer whales recorded in southern South America, in the Magellan Strait, Chile. The group consisted of four adult females, two juvenile females, and two females and one male of indeterminate age class. Total length of adult females averaged 572.8 ± 23.6 cm and juvenile females averaged 397.0 ± 24.0 cm. Dorsal fin height of adult females averaged 57.3 ± 8.5 cm and in juvenile females 30.5 ± 19.1 cm. No obvious signs of anthropogenic intervention were observed. The characteristic small post-ocular white eye patch of this killer whale ecotype measured 21.8 cm long and 5.9 cm wide in the freshest carcass found. All animals presented backswept dorsal fins and a dental formula of 11 to 13 maxillary and mandibular teeth. The length of the largest tooth in each individual ranged from 8.0 to 10.2 cm, suggesting that type D killer whales have smaller teeth. We suggest that the total length of type D killer whales is shorter than other killer whale ecotypes. After 67 years, we report the second known stranding of type D killer whales worldwide and we report for the first time body measurements, size, and number of teeth of this ecotype of killer whales.

Las colonias reproductivas de albatros de ceja negra (Thalassarche melanophris) se reconocen por su gran tamaño y presencia en islas oceánicas. Sin embargo, en el año 2003 se describe por primera vez la existencia de la única, y numéricamente pequeña, colonia reproductiva en aguas interiores de la Patagonia chilena ubicada en el islote Albatros (54°27’20’’S; 69°01’12’’W). A partir del año 2009, se inicia un estudio sistemático de esta colonia, visitando el área durante la temporada reproductiva para monitorear y evaluar su población. Se realizaron once expediciones entre los meses de octubre y febrero, durante los años 2009 y 2016, contabilizando la presencia de huevos y polluelos para determinar el éxito reproductivo de la colonia. Adicionalmente se anilló un total de 188 individuos a lo largo de 7 temporadas para determinar la tasa de recaptura durante estos años. A partir de estos monitoreos, se espera aportar nuevos antecedentes al conocimiento general sobre la pequeña colonia de albatros de ceja negra, única en el mundo ubicada en aguas interiores de la Región de Magallanes y de la Antártica Chilena

The ecological niche is dynamic, since the position and width of the niche can vary at different spatial and temporal scales. We examined the trophic ecology of southeast Pacific humpback whalesMegaptera novaeangliaein the Magellan Strait feeding area in 2011, 2012 and 2017, analyzing changes in diet and the width of the isotopic niche in relation to ontogeny and seasonality. The isotopic composition of carbon (δ13C) and nitrogen (δ15N) in whale skin and in putative prey species was analyzed. Bayesian mixing models were used to determine the diet, and the isotopic niche was estimated using the standard ellipse area. Differences were found between the diets of juveniles and adults; Fuegian spratSprattus fuegensiswas consumed mostly by adult individuals. We found no differences in the diet or in the isotopic niche of humpback whales throughout the feeding season in all years. This study suggests that the differences in diet between age classes are influenced by the ability to find and capture prey, whereas seasonality does not influence the niche width of humpback whales in the Magellan Strait. Our results suggested that fluctuations in the abundance of prey populations could influence in the trophic niche dynamics of humpback whales in the Magellan Strait. In particular, a reduction in the availability of Fuegian sprat would mainly affect adult individuals, leading to a dietary switch and/or to an expansion of their feeding area.

The eastern South Pacific southern elephant seal population was extinguished by extensive hunting and the current presence of this species in this area is not well understood. We reviewed existing records from the 1900s to 2014 in the eastern South Pacific, as well as tagged seals and movement records in order to assess the potential immigration source of these individuals. A total of 409 confirmed sightings were compiled, ranging from the southern tip of South America (Cape Horn Archipelago) as far north as Ecuador, including some oceanic island groups. The evidence shows also that recolonisation of its former Pacific distribution has started, with slow population growth in three incipient pupping sites in southern Chile (south of 51 degrees S). Although the source of all of the individuals in the growing colonies is unknown, evidence from tags and satellite tagging indicates that some seals come from subpopulations on the Peninsula Valdes and the Falkland/Malvinas Islands, although mtDNA analysis showed, preliminarily, a greater genetic relationship only with the Falkland/Malvinas Islands rookery.

Interactions between the longline toothfish (Dissostichus eleginoides) fisheries and cetaceans in the Southern Ocean have been registered over three decades. Two species primarily involved in these interactions are the sperm whale (Physeter macrocephalus) and the orca (Orcinus orca). Both species have been registered depredating on the longlines and fisheries have been substantially affected by the noticeable decrease on the catch. In this review, we summarized current knowledge about these interactions occurring south of 47°S in the industrial fleet. At present, interactions occur predominantly with the orca and in a lower extent with the sperm whale, after the modification of the fishing gear that diminished the depredation of the sperm whale. To date, many alternatives have been tested to repel cetaceans, including physical modifications of the fishing gear, acoustic devices, and changes in the fishing practices by the vessels, yet none seem effective. In the future, not one solution but a complex mix of actions must be coordinated effectively between the fishing operators, researchers, fishery engineers and State Public Institutions in order to diminish these interactions.

Interactions between the longline toothfish (Dissostichus eleginoides) fisheries and cetaceans in the Southern Ocean have been registered over three decades. Two species primarily involved in these interactions are the sperm whale (Physeter macrocephalus) and the orca (Orcinus orca). Both species have been registered depredating on the longlines and fisheries have been substantially affected by the noticeable decrease on the catch. In this review, we summarized current knowledge about these interactions occurring south of 47°S in the industrial fleet. At present, interactions occur predominantly with the orca and in a lower extent with the sperm whale, after the modification of the fishing gear that diminished the depredation of the sperm whale. To date, many alternatives have been tested to repel cetaceans, including physical modifications of the fishing gear, acoustic devices, and changes in the fishing practices by the vessels, yet none seem effective. In the future, not one solution but a complex mix of actions must be coordinated effectively between the fishing operators, researchers, fishery engineers and State Public Institutions in order to diminish these interactions.