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We examined how dietary factors recorded by C and N influence Hg uptake in 347 individuals of yellowfin tuna (Thunnus albacares), an important subsistence resource from the Galápagos Marine Reserve (Ecuador) and the Ecuadorian mainland coast in 2015–2016. We found no differences in total Hg (THg) measured in red muscle between the two regions and no seasonal differences, likely due to the age of the fish and slow elimination rates of Hg. Our THg concentrations are comparable to those of other studies in the Pacific (0.20‐9.60 mg/kg wet wt), but a subset of individuals exhibited the highest Hg concentrations yet reported in yellowfin tuna. Mercury isotope values differed between Δ199Hg and δ202Hg in both regions (Δ199Hg = 2.86 ± 0.04‰ vs. Δ199Hg = 2.33 ± 0.07‰), likely related to shifting food webs and differing photochemical processing of Hg prior to entry into the food web. There were significantly lower values of both δ15N and δ13C in tuna from Galápagos Marine Reserve (δ15N: 8.5–14.2‰, δ13C: −18.5 to −16.1‰) compared with those from the Ecuadorian mainland coast (δ15N: 8.3–14.4‰, δ13C: −19.4 to −11.9‰), of which δ13C values suggest spatially constrained movements of tuna. Results from the pooled analysis, without considering region, indicated that variations in δ13C and δ15N values tracked changes of Hg stable isotopes. Our data indicate that the individual tuna we used were resident fish of each region and were heavily influenced by upwellings related to the eastern Pacific oxygen minimum zone and the Humboldt Current System. The isotopes C, N, and Hg reflect foraging behavior mainly on epipelagic prey in shallow waters and that food web shifts drive Hg variations between these populations of tuna. Environ Toxicol Chem 2022;41:2732–2744. © 2022 SETAC [ABSTRACT FROM AUTHOR]

Mangrove forests of Ecuador's Gulf of Guayaquil are ecologically, culturally, and economically important to local communities relying on them for artisanal fishing, ecotourism, and related businesses. However, these ecosystems have experienced significant degradation by anthropogenic impacts such as anthropogenic marine debris. On one hand, plastics have improved the ease of life and safety for local people of the region; however, plastic pollution threatens the health of the mangrove ecosystem and these communities. This interdisciplinary study explores perceptions of marine litter and its impacts on community well-being based on surveys conducted in Puerto Hondo and Santay Island, two mangrove communities in the Gulf of Guayaquil, in 2019 and 2021. Santay Island respondents expressed that marine litter is an extreme issue affecting their well-being, while Puerto Hondo respondents reported less concern. Authors suggest Puerto Hondo's geographic link to Guayaquil city has transitioned the community into a "peri-urban" landscape, where community members increasingly look inland for basic needs. Conversely, Santay Island, isolated by estuarine water, is physically linked to the mangroves. It is suggested that as communities spend less time in the mangroves, whether geographically or socially separated, marine litter becomes "out of sight, out of mind" despite its ongoing impacts on local food security and historical heritage. This work illustrates the complexities of plastic use and marine debris. To foster equitable plastic waste governance for exposed coastal Ecuadorian communities, policies must not only account for these intricacies but also actively engage with and listen to local perspectives. [Display omitted] [ABSTRACT FROM AUTHOR]

The article offers information on several aspects associated with the live-stranded killer whale (Orcinus orca) in Coastal Ecuador along with insights on an occurrence of Killer Whale in Ecuadorian Waters. The topics addressed include details on the documented observations and unpublished records of killer whales (Orcinus orca) in coastal waters of Ecuador from 1996 to June 2017.

Abstract: The Southeastern Pacific Humpback whale Megaptera novaeangliae reproduces from June to September off the coast of Ecuador where a large artisanal fisheries fleet consisting of more than 15,000 vessels operates year round. The bycatch impact on this humpback population has been overlooked. Based on the annual bycatch mortality documented in this study, about 0.53% (95% CI 0.2–1.5%) of the population might be potentially bycaught in gillnets annually. Depending on the total population numbers estimated and reported elsewhere for this stock (2917 or 6277 whales), the bycatch mortality is equivalent to 15 or 33 whales per year. A significant correlation was found between the annual bycatch rate and fishing effort for the period 2000–2009 (r = 0.68, p < 0.05). An increase in artisanal fisheries may cause drastic consequences since humpback whales as K-strategists have low birth and survival rates. Calves are probably the most threatened age class due to gillnet entanglements in proximity to coastal waters where artisanal vessels operate. The Ecuadorian breeding grounds for humpback whales migrating from Antarctica might become a hot spot for bycatch in the Southeastern Tropical Pacific, if the bycatch rate continues to increase. Urgent mitigation strategies coupled with precautionary management and conservation measures are required to protect this vulnerable stock of whales in the long term. The consequences of humpback whale bycatch off coastal Ecuador and possible solutions to mitigate the bycatch are analyzed. [Copyright &y& Elsevier]

The article discusses a study on inshore feeding behavior of blue-footed boobies, or Sula nebouxii, in Ecuador during warming conditions in equatorial pacific ocean, citing that the boobies were feeding in a dense and coordinated group, and prey were highly local along the South American coast.

Background: Extralimital observations of pinnipeds are important to understand the effects of changing climates on our oceans and the distribution of these species. The southern elephant seal (Mirounga leonina) is a known vagrant species that moves over long distances. We report three new records of M. leonina in interior freshwater tributaries of the Guayas River Estuary Basin (Gulf of Guayaquil) and northern coast of Ecuador between October 2017 and January 2018 during a cold episode of La Nina event in the southeastern Pacific. Results: The elephant seals were identified according to their large size (~ 5 m for adult and 2–3 m for juveniles/subadults), the head to neck size ratio, and the size and external morphology of the proboscis, which was used as a key trait to differentiate M. leonina from the Northern elephant seal (M. angustirostris). The observations of M. leonina in Ecuador highlight an extreme movement covering an assumed total distance of approximately 8000 km from the circumpolar region. The cold event "La Niña" with sea surface temperature anomalies ranging − 1.5 °C to − 0.5 °C in October 2017 likely triggered the extralimital movements of these animals. Conclusion: Recurring observations of M. leonina in the Guayaquil Gulf suggest the importance of this highly productive region and tropical estuarine-riverine habitats as temporary haulout sites for resting. These new findings indicate that vagrant individuals influenced by oceanographic events and eco-physiological processes are reaching this region more frequently than previously thought. [ABSTRACT FROM AUTHOR]