Two new species of nasal mites of the genus Rhinonyssus (Acari, Mesostigmata, Rhinonyssidae) from shearwaters

Nasal mites of the family Rhinonyssidae are parasites living in the respiratory system of birds. To date there were no record of these mites from representatives of the order Procellariiformes, a numerous grouping of exclusively marine birds that includes albatrosses, petrels, storm-petrels and shearwaters. The paper describes two new species of the genus Rhinonyssus from shearwaters (Procellariidae) found on various shores of Brazil: Rhinonyssus borealis sp. nov. from Calonectris borealis (Cory’s shearwater) and R. procellaricus sp. nov. from Puffinus puffinus (Manx shearwater) and Ardenna gravis (Great shearwater). Both described mites are characterized by a large elliptical body and a relatively large and strongly sclerotized with the well-developed caudal extension. Rhinonyssus borealis sp. nov. and R. procellaricus sp. nov. are similar in their general appearance to each other but differ in the size of idiosoma, shape of podosomal and sternal shields and leg chaetotaxy.

Breeding of Cory's shearwater Calonectris borealis on Selvagem Grande and beneficial effects of removal of invasive mammals

The largest colony of Cory's shearwater Calonectris borealis nests on the island of Selvagem Grande in the north-eastern Atlantic. In 2002, a programme of eradication was conducted to remove two alien invasive mammals, the house mouse Mus musculus and European rabbit Oryctolagus cuniculus. Preliminary studies recorded beneficial effects of the eradications for a variety of plant and animal species, including Cory's shearwater. We recorded fledging rates of shearwaters for 1982–2001, prior to the eradication, and for 2002–2020, after the eradication, from two quadrats, each containing 134–329 nest sites. Although there was annual fluctuation in fledging rates in the quadrats, the mean rate of 40.74 ±SD 3.92 fledglings per 100 nest sites for the two quadrats combined prior to the eradication of mammals increased significantly, to 52.88 ± SD 5.03 per 100 nest sites, after the eradications. Because the two mammals were removed synchronously it is difficult to know which factors depressed fledging of Cory's shearwaters on Selvagem Grande. However, the predatory behaviour of house mice on other oceanic islands, and the fact that increased fledging was seen soon after the eradications occurred, suggest predation by house mice on shearwater hatchlings was the main cause of losses.

Low spatial overlap between foraging shearwaters during the breeding season and industrial fisheries off the west coast of Portugal

Fisheries have impacted seabird populations worldwide, either via bycatch mortality or resource depletion. Understanding the overlap between seabird distributions and fisheries is an important element for bycatch risk assessment, though the drivers of variation in seabird-fishery overlap are not well understood for some seabird populations. Here, we quantified the spatial overlap between foraging Cory’s shearwaters Calonectris borealis during the breeding season and commercial fisheries operating within the Portuguese Exclusive Economic Zone. In addition, we evaluated whether overlap varied as a function of an individual’s boldness, sex or breeding stage. For this, we GPS tracked 361 foraging trips by 72 Cory's shearwaters nesting at Berlenga Island, Portugal, over 5 consecutive breeding seasons (2012-2016). Simultaneously, we used fishing effort data from Global Fishing Watch detailing the distribution of industrial fisheries within the temporal and spatial range of Cory's shearwater tracks. Although fishing vessels were present during 88.1% of foraging trips, Cory's shearwaters spent only on average 13.3% of the time foraging in the same areas as fisheries. Such low spatial overlap is likely driven by high prey availability near the colony and suggests low direct competition for resources. We also found variation in overlap with fisheries across the breeding period, with Cory's shearwaters spending approximately 11% more time foraging in the same areas as fixed gear and purse seine vessels during pre-laying than during chick-rearing. Surprisingly, no sex or boldness-related differences were found in the overlap with any fishing gear. Our findings have implications for understanding within population variation in the overlap between fisheries and seabirds and, in turn, bycatch risk.

Wildlife inventory from camera-trapping surveys in the Azores (Pico and Terceira islands)

The present publication provides a dataset from five camera-trapping sampling campaigns on two islands of the Azorean archipelago (Pico and Terceira islands), between 2013-2018. This dataset was obtained as a by-product of campaigns designed for different purposes. The sampling campaigns were designed to: (i) study the ecology of introduced mammals; (ii) assess the impact of introduced mammals on native birds (Azores woodpigeon - Columba palumbus azorica and Cory's shearwater - Calonectris diomeda borealis), through nest predation; and (iii) obtain information about the impact of vertebrates on agricultural systems, particularly on Azorean traditional vineyards. A total of 258 sites and 47 nests were sampled using camera traps. These sampling campaigns provided a large data series that allowed the creation of a vertebrate wildlife inventory. We obtained a total of 102,095 camera-trap records, which allowed us to to identify 30 species of vertebrates: one amphibian, one reptile, 17 birds and ten mammal species. This represented 100% of the amphibians and terrestrial mammals, 58% of the breeding birds and 50% of the reptile species known for Pico and/or Terceira islands. Concerning the colonisation status of the species, we recorded 15 indigenous (native non-endemic or endemic) and three introduced bird species; all known terrestrial amphibians, reptiles and mammals in the Azores are introduced species. The data collected contribute to increasing knowledge on the distribution of vertebrate species on Pico and Terceira islands, where most existing records of some species were only available to Island level (e.g. mustelids and hedgehogs). None of the identified species was previously unknown to the study area.

Identifying main interactions in marine predator–prey networks of the Bay of Biscay

Identifying the role that environmental factors and biotic interactions play in species distribution can be essential to better understand and predict how ecosystems will respond to changing environmental conditions. This study aimed at disentangling the assemblage of the pelagic predator–prey community by identifying interspecific associations and their main drivers. For this purpose, we applied the joint species distribution modelling approach, JSDM, to the co-occurrence patterns of both prey and top predator communities obtained from JUVENA surveys during 2013–2016 in the Bay of Biscay. Results showed that the co-occurrence patterns of top predators and prey were driven by a combination of environmental and biotic factors, which highlighted the importance of considering both components to fully understand the community structure. In addition, results also revealed that many biotic interactions, such as schooling in prey (e.g. anchovy–sardine), local enhancement/facilitation in predators (e.g. Cory’s shearwater–fin whale), and predation between predator–prey species (e.g. northern gannet–horse mackerel), were led by positive associations, although predator avoidance behaviour was also suggested between negatively associated species (e.g. striped dolphin–blue whiting). The identification of interspecific associations can therefore provide insights on the functioning of predators–prey network and help advance towards an ecosystem-based management.