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This study investigated the level of seabird mortality caused by the domestic trawl fleet (freshies) for hake (among other less important targets) operating in waters off central Patagonia (37-48°S), analyzing the effect of environmental and operational variability on the level of seabird interactions. With a total of 135 vessels, the fleet is one of the largest in Argentina. Specifically tasked seabird observers were placed onboard trawlers during the summer and winter seasons of the years 2006 and 2007. The type and number of seabird interactions (i.e. contacts with fishing gear) were recorded during shooting and hauling operations, covering 72 days of observation and 328 trawls. Black-browed albatrosses, white-chinned petrels Procellaria aequinoctialis, southern giant petrels Marconectes giganteus and southern royal albatrosses Diomedea epomophora were the most abundant species interacting with trawlers. Confirmed mortalities of black-browed and southern royal albatrosses were the result of collisions and entanglement with the warp cable while birds were scavenging. The estimated total mortality rate was 0.017 birds h and 0.105 birds per vessel per day. The intensity of interactions (in terms of the number of contacts per unit time) was largely explained by the distribution of the fishing effort. Seasonality and the incidence of discards were the strongest factors explaining the occurrence of seabird interactions. The total annual mortality in the trawl fleet under investigation was roughly estimated to be from several hundred to over a thousand albatrosses. However, these figures should be considered preliminary due to the limited spatial and temporal coverage of data and the fact that estimations were based on a low number of observed mortalities. The implementation of a strategic discard management may significantly reduce the number of seabird mortalities from collisions with warp cables or improve the effectiveness of other complementary mitigation methods. Urgent implementation of mitigation measures is needed in this fleet to reduce the mortality of albatrosses and petrels along the Patagonian shelf. [ABSTRACT FROM AUTHOR]

The increasing popularity of outdoor recreational activities in recent years has resulted in elevated human disturbance of waterbird communities. Anthropogenic disturbance is defined as any human activity that constitutes a stimulus sufficient to disrupt normal activities and/or distribution of animals relative to the situation in the absence of that activity. The goals of this study were (1) to quantify changes in habitat use by waterbirds caused by the proximity of people’s activities to the shoreline, in Los Padres Lagoon Reserve (Argentina), (2) to evaluate differential responses of waterbird groups caused by this human disturbance, and (3) to propose management guidelines to improve waterbird conservation in Pampas lagoon. We performed bird surveys monthly in areas with high levels of disturbance (HD areas) and with no or low levels of disturbance (LD areas) via recreational activities during days with (weekends) and without (weekdays) presence of people close to the lagoon. We recorded 34 bird species using the lagoon. The bird richness and abundance in HD areas was higher in days without recreational activities, conversely, in LD areas we found no differences in these parameters between days. Waders were found to be the group most vulnerable to disturbance, since these birds were only recorded in HD areas in days without human activity. Podicipedidae, as a group were less affected by recreational activities. We detected changes in the waterbird assembles and structure in relation to the presence of people on the shoreline. Our results in this study suggest direct effects of recreational activities on the habitat use of waterbirds. The buffer area defined by the current Reserve management strategy is working properly, and the impact of recreational activities on transitional area has only instantaneous effects on waterbirds because they return to that area in absence of disturbance. However, it should be considered that we only estimated the response to short-term effects of these activities on the waterbird community. Further studies should assess long-term effects. [Copyright &y& Elsevier]

Abstract: Incidental mortality of seabirds caused by longline fisheries in the south-western Atlantic Ocean has been assessed only with reference to the number of birds caught, not taking into account how the configuration of the gear affects mortality. We provide the first direct estimates of the impact on seabirds of the semi-pelagic fishing gear used in the Argentine Kingclip Genypterus blacodes fishery. The gear included weights and buoys, sequentially spaced along the lines, which enabled fishing to occur at different depths. During a fishing trip onboard the F/V Argenova XII in the austral summer of 2005, 74 birds were captured, comprising 56 White-chinned petrels Procellaria aequinoctialis and 18 Black-browed albatrosses Thalassarche melanophrys. More than half of the hooked birds were caught in the first third of the lines being set, and almost all White-chinned petrels (96%) and Black-browed albatrosses (83%) were caught within 30m (i.e. 24 hooks) of buoys. The floats used in semi-pelagic longlines are likely to decrease the sinking rates of baited hooks near them, buoying up the lines near the surface and increasing the likelihood of seabird interactions. Although we lack information on the distribution of captured fish along these longlines, the most feasible methods to reduce seabird bycatch in the Argentine semi-pelagic longline fishery would be (1) to deploy lines without hooks near line floats (the removal of 24 hooks either side of each float should substantially reduce seabird interactions with gear) or (2) to use long snoods between the mainline and the floats, allowing the baited hooks to quickly sink beyond the reach of seabirds. [Copyright &y& Elsevier]

Innovation, a process that plays an important role in the ecology and evolution of species, is considered an expression of behavioral flexibility in animals. Here we analyzed innovative problem-solving ability and performance enhancement through learning in the Olrog's Gull (Larus atlanticus), under controlled processes and experimental conditions. Trials were undertaken with nine adult individuals captured at a highly urbanized coastal area of Argentina. Each individual was presented with a Plexiglas box that could be opened by pushing or pulling two lids, each lid leading to a separated food reward. We measured problem-solving ability through consumption latency and the number of solved lids. As explanatory variables, we measured contact rate, as a measure of persistence, and the number of effective contacts. The results showed that the contact rate and effective contacts did not affect variables related to problem-solving ability during the first confrontation of the individuals with the closed box. Consumption latency decreased significantly throughout the trials, and with increasing contact rate and effective contacts. The number of solved lids increased through the trials independently of the contact rate and the total effective contacts with the box. Although persistence did not influence individuals' performance during the problem-solving test; this variable affected individuals' ability to solve the task throughout trials. Learning was evidenced by the decrease in the resolution time across experiments, suggesting that successful individuals improved their performance probably through a trial-and-error process. Evaluation of behavioral responses of a threatened seabird to a novel problem-solving task adds knowledge to previous field studies and provides a better understanding of the ability of individuals to adjust their foraging behavior in highly urbanized areas used during the non-breeding season., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Ecophysiology and conservation studies often require the prior establishment of baseline physiologic metrics. For instance, expected reference intervals for health metrics are valuable tools for veterinarians and conservationists who monitor the health status of endangered populations and species. This study establishes reference intervals for hematologic metrics in free-ranging Olrog's gull ( Larus atlanticus ) during the nonbreeding season. Fifty-six gulls (immature and adults) were captured and studied in Mar del Plata and neighboring coastal areas (Buenos Aires, Argentina) during the winter of 2018 ( n = 22) and 2019 ( n = 34). Hematocrit, red blood cells (erythrocytes), hemoglobin, mean cell volume, mean cell hemoglobin (MCH), MCH concentration, white blood cells (WBC; leukocytes), heterophils, lymphocytes, eosinophils, monocytes, and basophils were analyzed. Additionally, the variability of hematologic metrics according to body weight, sex, age, and calendar year was examined. Hematologic metrics were in line with those reported in other seabird species. Males had greater body weight and MCH than females. The heterophil to lymphocyte ratio and lymphocyte levels were higher in adults than in immatures. Hematocrit, WBC, heterophils, and basophils also varied significantly between calendar years. The results highlight the importance of appropriate metrics and reference intervals for monitoring the health status of this threatened species, and it is recommended to implement such comparative assessments among populations.

The use of bird feathers to assess environmental contamination has steadily increased in ecotoxicological monitoring programs over the past decade. The Olrog's Gull (Larus atlanticus) is a species endemic to the Atlantic coast of southern South America, constituting one of the three threatened gull species listed in the entire American continent. The aim of this study was to assess the exposure to Persistent Organic Pollutants (POPs) and chlorpyrifos in the Near Threatened Olrog's Gull through the analysis of body feathers sampled at the Mar Chiquita coastal lagoon, the main wintering area of the species in Argentina, controlling for sex and age class. Chlorpyrifos showed the highest concentrations among all contaminants and groups of individuals (X¯ = 263 ng g -1 ), while among POPs the concentration of organochlorine pesticides was higher than polychlorinated biphenyls and polybrominated diphenyl ethers, likely indicating the current use of these agricultural contaminant in the region. The highest values of total POP concentrations (males X¯ = 280 ng g -1 , females X¯ = 301 ng g -1 ) were found in juvenile gulls, likely as a consequence of the incorporation of pollutants during the breeding season. Subadult and adult birds showed difference between sexes in the concentration of contaminants, with higher levels in males than females. The results highlight the need to include birds of different sex and age classes in order to better understand the variation in pollutants loads. The present study provides relevant information to improve the conservation status of the Olrog's Gull and new insights about the environmental health of the Mar Chiquita coastal lagoon, Argentina, a MAB-UNESCO World Biosphere Reserve. However, there is a continued need for long-term monitoring programs focusing on this threatened species to understand the effects of pollutants on its population., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Seabirds have been widely used for monitoring the health of the oceans in diverse marine regions. Among low-cost survey strategies, systematic surveys of seabirds beached on coasts have been developed since the 20th century. However, these studies do not always address blood aspects. The assessment of the health status of birds based on the analysis of hematological and plasma chemistry is crucial to evaluate the overall health status profile of live organisms. Here, the authors study the variability of blood parameters by sex, age class, and year of beached Magellanic Penguin during the nonreproductive period in northern Argentina. Of 44 penguins, 77% were categorized as younger juveniles and the rest as older juveniles, and were captured and studied in coastal areas of Buenos Aires Province during the summers of 2017 and 2018. The mean body weight of beached penguins was affected by the age class of the individuals; most of the younger juveniles showed poor condition in terms of body mass (1,761 ± 235 g). No significant differences were observed in body weight between years and sex. Still, there were significant differences between years for alkaline phosphatase (ALP) and creatine phosphokinase (CPK) values. Twelve of the 20 blood parameters analyzed differ significantly with the age class of the beached penguins; younger juveniles were in a state of inanition. Our results may serve as a necessary first step in improving the conservation status of the Magellanic Penguin in nonbreeding grounds of Argentina, and call for a better knowledge of the health status of the species along its annual cycle.

Persistent Organic Pollutants (POPs) are accumulated through time and can exert different effect on ecosystems. POPs and Chlorpyrifos, a current use pesticide, were assessed in body feathers of males and females of Black-browed albatross (Thalassarche melanophris, BBA) and Cape petrels (Daption capense, CAP) during their non-breeding seasons at the Patagonian Shelf, Argentina. Chlorpyrifos showed the highest values among all pollutants in both species (49.56-84.88 ng g -1 ), resulting from current agricultural practices. The pattern OCPs > PCBs > PBDEs was observed in both species, and CAP showed higher concentrations than BBA probably as a consequence of higher lipid mobilization and pollutants availability during dispersion. Non-significant differences between sexes about POPs levels were found; however a slight tendency was observed, females>males in CAP, and males>females in BBA. More attention and further studies are needed to understand seabirds' physiology and its relationship with the pollutants distribution in their tissues and considering breeding season., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Analysis of serum parameters provides information about body condition, nutritional state, and health status of individuals/species, and has broad application in ecological research and veterinary diagnosis. This study establishes baseline values for serum chemistries of the Olrog's gull ( Larus atlanticus ). Glucose, urea, uric acid, total protein, globulin, albumin, cholesterol, triglyceride, calcium, and phosphorus concentrations were determined, as was the activity of the following enzymes: alkaline phosphatase, creatine phosphokinase, aspartate aminotransferase, and alanine aminotransferase. Thirty nonbreeding gulls (juvenile and subadult individuals) were captured and studied in Mar Chiquita Reserve (Buenos Aires, Argentina) during the wintering periods 2016 ( n = 17) and 2017 ( n = 13). In general terms, most values for the parameters reported were in line with those previously described for other seabirds. The year had a significant effect on several of the biochemical parameters evaluated, and the sex had a significant effect on the alkaline phosphatase and calcium. This study has defined the serum biochemical reference signatures for free-ranging Olrog's gulls during the nonbreeding period, and contributes to the knowledge of the overall health status of this threatened and endemic species., (Copyright 2019 by American Association of Zoo Veterinarians.)

We investigated the concentrations of cadmium, chromium, copper, iron, nickel, lead and zinc among feather tissues in sexes of Black-browed Albatross Thalassarche melanophrys killed in longliners off Argentina in 2005. We found no different metal concentration with sex for cadmium, copper, iron, lead and zinc in feathers of adult birds, though there were significant body-size differences between sexes. However, the concentrations of trace metals differed significantly among the type of feather within individual bird. The mean concentrations of copper, iron, and zinc in breast feathers of T. melanophrys were lower than those reported for the species from Georgias del Sur/South Georgia, the southern Indian Ocean and for other seabirds' worldwide. While cadmium fall within the known range of concentrations for bird feathers lead were not. Our results may be indicating that level of pollution in Patagonia may not be as negligible as previously thought at least for some trace metals., (Copyright © 2011 Elsevier Ltd. All rights reserved.)