Lucas Krüger

Projected distributions of Southern Ocean albatrosses, petrels and fisheries as a consequence of climatic change

Given the major ongoing influence of environmental change on the oceans, there is a need to understand and predict the future distributions of marine species in order to plan appropriate mitigation to conserve vulnerable species and ecosystems. In this study we use tracking data from seven large seabird species of the Southern Ocean (Black-browed Albatross Thalassarche melanophris, Grey-headed Albatross T. chrysostoma, Northern Giant Petrel Macronectes halli, Southern Giant Petrel M. giganteus, Tristan Albatross Diomedea dabbenena Wandering Albatross D. exulans and White-chinned Petrel Procellaria aequinoctialis , and on fishing effort in two types of fisheries (characterised by low or high-bycatch rates), to model the associations with environmental variables (bathymetry, chlorophyll-a concentration, sea surface temperature and wind speed) through ensemble Species Distribution Models. We then project these distributions according to four climate change scenarios built by the Intergovernmental Panel for Climate Change for 2050 and 2100. The resulting projections were consistent across scenarios, indicating that there is a strong likelihood of poleward shifts in distribution of seabirds, and several range contractions (resulting from a shift in the northern, but no change in the southern limit of the range in four species). Current trends for southerly shifts in fisheries distributions are also set to continue under these climate change scenarios at least until 2100; some of these may reflect habitat loss for target species that are already over-fished. It is of particular concern that a shift in the distribution of several highly threatened seabird species would increase their overlap with fisheries where there is a high-bycatch risk. Under such scenarios, the associated shifts in distribution of seabirds and increases in bycatch risk will require much-improved fisheries management in these sensitive areas to minimise impacts on populations in decline. This article is protected by copyright. All rights reserved.

Strange lights in the night: using abnormal peaks of light in geolocator data to infer interaction of seabirds with nocturnal fishing vessels

Many seabird species forage at night and potentially interact with nocturnal fishing activities. Jigging fisheries use powerful lights to attract squid, and such high intensity lights can be recorded using global location-sensing loggers (geolocators) attached to seabirds. We use this potential source of information as evidence for interaction of southern giant petrels Macronectes giganteus with night fisheries during the non-breeding season. We compared the number of light spikes at night between sexes and evaluated whether the intensity of the light on those geolocator records matched periods of water immersion (wet–dry) of geolocators, as a measure of foraging activity. Females had more night light spikes than males, and although the activity on water was higher during nights with light spikes than nights without light spikes for both sexes, females had a higher probability to be resting on the water when peaks of light were higher. Females moved further north than males and used areas of higher squid fishery activities within Patagonian waters. This type of information is useful to record potential interactions with night fisheries and proposes that future studies should relate the accurate distribution of individuals (from GPS loggers) with light information (geolocators data) to highlight this undocumented interaction. Southern giant petrels are recognized as interacting intensively with fisheries off Patagonia waters with consequences for population dynamics (e.g. mortality through bycatch events).

Incidence of plastic debris in Sooty Tern nests: A preliminary study on Trindade Island, a remote area of Brazil

Plastic is abundant in the oceans, reaching pelagic zones away from continents. Here we present the first recordings of plastic used as nest material in Sooty Tern nests, on a remote oceanic island. We describe our findings in terms of quantity, size and color of plastic debris. A total of 78 plastics were noted in 54 nests. Four color categories were found: Blue, White, Green and Red. Blue fragments were the most frequent color, present three times as much as white debris. This pattern was present despite blue fragments being smaller and lighter. The plastic debris of lowest frequency were the larger and heavier pieces (red). To our knowledge this is the first record of plastic in Sooty Tern nests. Trindade Island is on an oceanic zone expected to accumulate garbage due to the dynamic ocean currents. Such findings call for a closer inspection of pollution in the Atlantic Ocean.

Population estimate of Trindade Petrel Pterodroma arminjoniana by the use of Predictive Nest Habitat Modelling

The Trindade Petrel Pterodroma arminjoniana is a vulnerable species that breeds on Trindade Island, 1,100 km away from the Brazilian coast, and on Round Island in the Indian Ocean. Recent population estimates for Trindade Island by nest counts in accessible areas, and extrapolated to the whole island provided a figure of 1,130 breeding pairs. Using topographic variables and Predictive Nest Habitat Modelling from known breeding sites, we estimated the potential area of nesting and estimated the size of the breeding population. Nests were associated with low to intermediate elevations in areas of steep slopes and high runoff, which limited the distribution of potential breeding sites to the edges of the Island. By extrapolating the density of nests in the known breeding sites to the overall potential breeding area, we estimated 1,228 nests. We discuss the potential implications of our findings in relation to the population status based on the scenario of intense habitat modification of the island over the few last centuries. This species may have suffered declines due to habitat alteration by human activities and introduction of exotic species. Furthermore, we generate an overview of potential areas for nesting and establish relationships with habitats that may be useful for the conservation of the Trindade Petrel, and restoration actions for Trindade Island in the future.

Seabird breeding population size on the Antarctic Peninsula related to fisheries activities in non-breeding ranges off South America

Abstract Population growth of the southern giant petrel Macronectes giganteus from South America has been linked with an increase in fishing activities. It was demonstrated recently that a population from Elephant Island, Antarctic Peninsula, largely overlaps its non-breeding distribution with zones of high fishing intensity off South America. This study investigated the assumption that the increase in this population since the 1980s is related to an increase in fisheries off South America. Our results show that the population size is proportional to the increase in demersal and squid fisheries. These fisheries produce a considerable amount of discards, which can be used by non-breeding southern giant petrels as a food source during unfavourable conditions in winter. This may enhance the adult survival rates with potential carry-over effects on population size. Our study shows that we need to further understand the effects of fishery discards/offal on scavenging seabirds of the Southern Ocean, and highlights the importance of understanding the carry-over effects of seabird–fisheries interactions during the non-breeding phase in population dynamics.

Evidence of an unreported negative effect of fisheries discards on seabirds: death by choking on the Atlantic Midshipman (Porichthys porosissimus) in southern Brazil

Abstract The effects of the fishing industry on the marine environment have been studied and described over the past two decades. Trawl-netting is a common but non-selective method of fishing that often captures non-target specimens of no commercial value that are discarded at sea. We discovered an unreported threat caused by fisheries discards on seabirds attending fishing activities in Brazilian waters: choking by feeding on discarded Atlantic Midshipman (Porichthys porosissimus). Over 6 years of monitoring (2007–13), we recorded five procellariiform species—Atlantic Yellow-nosed Albatross (Thalassarche chlororhynchos), Corys Shearwater (Calonectris diomedea), Sooty Shearwater (Ardenna grisea), Great Shearwater (Ardenna gravis) and Manx Shearwater (Puffinus puffinus)—dead on beaches with Atlantic Midshipman stuck in their throats and showing evidence of death by suffocation as a result of blockage of the airways through choking. This phenomenon has not been consistently described, and the consequences of the consumption of fishery discards by seabirds in Brazilian waters remain poorly understood.

DISTRIBUTION OF SEABIRD COLONIES IN STINKER POINT, ELEPHANT ISLAND

Stinker Point is located on Elephant Island. It presents an ice-free area where di erent seabird species breed during the austral summer. To evaluate the distribution of Antarctic seabird breeding sites, colonies and breeding groups were mapped into the study area. ere are breeding colonies of 13 species. Southern Giant Petrel Macronectes giganteus and Wilson’s Storm-petrel Oceanites oceanicus are the species with most breeding groups mapped, totaling 10 of both species, followed by Cape Petrel Daption capense with nine breeding groups recorded. e high number of species observed in Stiker Point con rms the signi cance of this area as an Important Bird Area in Antarctica (IBA 071).

INFLUENCE OF SEA SURFACE TEMPERATURE ON PELAGIC SEABIRD DISTRIBUTION IN THE SOUTH ATLANTIC OCEAN

Seabird distribution is mostly related to high primary productivity zones, as well as to abiotic factors, such as hydrographic conditions. is study aimed at evaluating the in uence of sea surface temperature on Antarctic and sub-Antarctic seabirds in the South Atlantic Ocean. Sampling was conducted on board between Rio Grande, Brazil, and Antarctica from 2009 to 2012. A PCA was performed to identify the species associations and Linear Regressions were used to identify the relation with sea surface temperature. We registered 22 Procellariiformes species, belonging to three families: Procellariidae (n=13), Diomedeidae (n=7), and Hydrobatidae (n=2). ree distinct species groups were identi ed, and two presented a signi cant relationship with sea surface temperature.

Southern Giant Petrel Macronectes giganteus Nest Attendance Patterns under Extreme Weather Conditions

Differences in nest attendance between genders in seabirds may be related to morphological differences. Southern giant petrel is a dimorphic species with gender-specific foraging behavior. The objective of this study was to investigate sex-related differences in nest attendance during the breeding period of southern giant petrels by presence/absence patterns of both sexes during incubation and compare use of the colony after nest failure. Fourteen birds were tagged with digitally coded radio-transmitters in a colony at Elephant Island, Antarctica, in the beginning of 2009/2010 breeding season. Females were present during 18 periods (min. 3 days, max. 9 days) and males only in five periods (min. 2 days, max. 13 days). The difference in mean number of radio signals per day between females (4330; s.e. 313.5) and males (2691; s.e. 248.6) was highly significant (t = 4.3; d.f. = 199; P < 0.001; Fig. 4). As consequence of the severe weather conditions that year, all tagged birds failed to reproduce. After abandonment of the nests, the presence of both genders decreased drastically, although the tagged individuals stayed in the area. Under severe weather conditions female Southern Giant Petrels continue breeding while males abandon the nest earlier.