Numbers Of Seabirds Research Articles

Seabird and marine mammal attendance in the Chub mackerel Scomber japonicus semi-industrial Argentinian purse seine fishery

We assessed for the first time marine bird and mammal attendance in the Chub mackerel Scomber japonicus semi-industrial coastal purse seine fishery in northern Argentina. Information was gathered during a fishery run from late spring 2007 to early summer 2008. Sixteen marine top predator species attended vessels, and the most abundant seabirds (percent of overall individuals and percent of occurrence) were the Kelp Gull Larus dominicanus (25% and 40% respectively), and White-chinned Petrel Procellaria aequinoctialis (24% and 47% respectively). Other attending bird species were the Black-browed Albatross Thalassarche melanophrys (18.5% and 12% respectively) and South American Tern Sterna hirundinacea (30% and 22% respectively). The most abundant marine mammal's species was the South American Sea Lion Otaria flavescens (2% and 8% respectively). Analysis of environmental and operational variability affecting the abundance of the four main seabird species indicated a clear spatial variability in the numbers of seabirds attending coastal purse seiners. Other factors included fishing operation, time of day, seasonality, and wind intensity and wind direction. Neither seabird nor marine mammal species were observed to be incidentally taken during 82 fishing operations. The results of this study showed that the semi-industrial purse seine fishery operating in coastal waters in northern Argentina may have a relatively minor impact on some marine top predator populations mainly because (1) the fishing grounds are close to shore, and at relatively shallow depths, and (2) for economic reasons, the fishing fleet operates at considerable distance from dense schooling areas. Still, it has to be stressed that data were obtained during operations in which the levels of discards (<2%) were by far lower than the average of 30% reported in the literature. Given this background, further studies including long-term monitoring are needed for an adequate modeling of the interactions and the identification of core areas for seabirds interacting with purse seiners in the waters of northern Argentina.

Harvesting Seabirds and their Eggs on the Irish Sea Islands (Part 4: Environmental and Cultural Influences)

Seabird populations have been affected by fisheries, climate, predators, and other pressures these past two hundred years. These had little proven impact on such traditional fowling activities as were still practised around the Irish Sea, but they coincided with fast-developing industrialization and profit-maximization. Vast numbers of seabirds and their eggs were sought for food, feathers, and oil; and a growing conservation lobby sought their legal protection. Collectively, these pressures triggered a rapid decline in commercial exploitation and ended most subsistence fowling, the main exception being relatively modest twentieth-century wartime revivals.Apart from occasional references, and bird bone from archaeological sites, little evidence survives for earlier harvesting of seabirds (other than on the Calf of Man and Rathlin). Conversely, many small Irish Sea islands appear to have been used as rabbit warrens and grazings from the twelfth century, parts of bigger mainland estates. This suggests that many were cleared of earlier cultures and traditions under the influence of (Anglo-)Norman/Flemish overlordship. Seabird harvesting traditions that survived on Rathlin into the mid-twentieth century, and the possible interaction of Celtic, Norse, and other fowling traditions around the Irish Sea, are now explored in Parts 5 and 6 (Folk Life, forthcoming).

Improving the accuracy of population size estimates for burrow‐nesting seabirds

Seabird numbers can change rapidly as a result of environmental processes, both natural and anthropogenic. Informed management and conservation of seabirds requires accurate and precise monitoring of population size. However, for burrow‐nesting species this is rarely achieved due to spatial and temporal heterogeneity in burrow occupancy. Here, we describe a novel method for deriving more accurate population size estimates that employs mark‐recapture methods to correct for unknown variation in nest occupancy throughout a breeding season. We apply it to estimate breeding numbers of a colonial, burrowing seabird, the Little Penguin Eudyptula minor, on the Summerland Peninsula, Phillip Island, Australia. Estimates of active burrow numbers during the September 2008 to February 2009 breeding season were adjusted to numbers of breeding birds based on burrow occupation and modelled population demographics at six, fortnightly monitored reference sites. The population was estimated to be 26 100 (95% CI: 21 100–31 100) and 28 400 (23 800–33 000) breeding Penguins in two temporally separated surveys within one breeding season. We demonstrate using simulation that the method is robust to variation in burrow occupancy throughout the breeding season, providing consistent and more accurate estimates of population size. The advantage of using the corrected method is that confidence intervals will include the true population size. Confidence limits widened as burrow occupancy declined, reflecting the increased uncertainty as larger adjustments for low burrow occupancy were required. In contrast, the uncorrected method that uses burrow occupancy alone as a measure of breeding numbers was inconsistent and significantly underestimated population size across much of the breeding season. Although requiring considerably more survey effort, the corrected approach provides a more accurate means for monitoring population changes in colonially breeding animals while collecting demographic data that can help diagnose the drivers of population change.

Populations and trends of Canadian Arctic seabirds

Canada’s eastern Arctic (Nunavut and Arctic Quebec—Nunavik, N of 60°) supports large numbers of seabirds in summer. Seabird breeding habitat in this region includes steep, rocky coasts and low-lying coasts backed by lowland sedge-meadow tundra. The former areas support colonial cliff- and scree-nesting seabirds, such as murres and fulmars; the latter inland or coastal seabirds, such as terns, gulls and jaegers. The region supports some 4 million breeding seabirds, of which the most numerous are thick-billed murres (Uria lomvia; 75%), black guillemots (Cepphus grylle; 9%), northern fulmars (Fulmarus glacialis; 8%) and black-legged kittiwakes (Rissa tridactyla; 6%). The majority of Arctic seabirds breed in a small number of very large colonies (>10,000 birds), but there are also substantial numbers of non-colonial or small-colony breeding populations that are scattered more widely (e.g. terns, guillemots). Population trends among Canadian Arctic seabirds over the past few decades have been variable, with no strongly negative trends except for the rare ivory gull (Pagophila eburnea): this contrasts with nearby Greenland, where several species have shown steep declines. Although current seabird trends raise only small cause for concern, climate amelioration may enable increased development activities in the north, potentially posing threats to some seabirds on their breeding grounds.

Utilisation of discards from small-scale fisheries by seabirds in coastal waters of Paraná State, Brazil

Fishery discards support scavenging seabird populations in many parts of the world, but little is known of this relationship in Brazil. The present study of the coast of Paraná, southern Brazil conducted monthly surveys over twelve months. We observed nine species of scavenging seabirds taking discards, Magnificent Frigatebird Fregata magnificens and Brown Booby Sula leucogaster being the most abundant and frequent. The highest numbers of scavenging seabirds were observed during trawling activities, which provided far more discards at sea than driftnet fishing. During a fishing moratorium, when no use of trawl nets was permitted, numbers of scavenging seabirds at boats were lower. It seems likely that scavenging seabird populations of the Paraná coast benefit from this supplementary food supply, but the extent to which their numbers are affected is unknown.

An assessment of seabird–fishery interactions in the Atlantic Ocean

Abstract Tuck, G. N., Phillips, R. A., Small, C., Thomson, R. B., Klaer, N. L., Taylor, F., Wanless, R. M., and Arrizabalaga, H. 2011. An assessment of seabird–fishery interactions in the Atlantic Ocean. – ICES Journal of Marine Science, 68: 1628–1637. Currently, 17 of 22 albatross species are listed as Vulnerable, Endangered, or Critically endangered by the International Union for the Conservation of Nature (IUCN). Incidental mortality in fisheries is by far the most widespread cause of the population declines observed for these and other closely related species. In 2006, the International Commission for the Conservation of Atlantic Tunas (ICCAT) requested an assessment of the threat from their fisheries to all seabirds that breed or forage within their jurisdiction. Methods were developed to assess the potential consequences of fishing for more than 60 populations of seabird. The assessment framework involved the identification of at-risk populations, overlap analyses, estimation of total bycatch, and an evaluation of the impact of the bycatch on key selected populations for which there were sufficient data on bird distribution and demography. These were the wandering and black-browed albatrosses of South Georgia and the Atlantic yellow-nosed and Tristan albatrosses of Gough Island. Summary results from the seabird assessment are presented, revealing that ICCAT longline fisheries catch substantial numbers of seabirds, with potentially significant conservation implications. If this mortality is not reduced, the numbers of breeding birds in some populations will continue to decline, threatening their long-term viability.

Summary of Birds Killed by a Harmful Algal Bloom along the South Washington and North Oregon Coasts During October 20091

Seabirds are known to be vulnerable to biotoxins produced by harmful algal blooms (HABs). The ingestion of prey contaminated with biotoxins such as domoic acid can cause disorientation, seizures, morbidity, and mortality (Work and others 1993). During November 2007 in Monterey Bay, California, an unprecedented stranding of live and dead seabirds highlighted plumage fouling as an emerging mortality factor during harmful algal bloom (HAB) events. The fouling agent was a proteinaceous foam derived from the cellular breakdown of the dinoflagellate Akashiwo sanguinea. This foam coated seabird plumage in a manner similar to fouling by petroleum oil (Hartung 1967; McEwan and Koelink 1973; National Research Council 1985), causing waterlogging, hypothermia, morbidity, and mortality in the California birds (Jessup and others 2009). During late October 2009 along the southern Washington and northern Oregon State coasts, algal blooms caused another seabird plumage fouling event, where several bird species were coated in a foam surfactant. Water and feather samples confirmed that this dinoflagellate bloom was also A. sanguinea (Dr. Raphael Kudela, University of California Santa Cruz, Santa Cruz, CA, pers. comm.). Du and others (in press) describe the conditions that facilitated the A. sanguinea bloom off the Oregon coast and propose that the source of the bloom was southward transport of cells from a massive September bloom that first occurred off the Washington coast. Similar to the 2007 California event, the foam produced by the WashingtonOregon bloom reduced the waterproofing of birds’ plumage, causing hypothermia in individual birds and leading to the stranding of hundreds of debilitated live and dying seabirds on public beaches. During this event, volunteers and federal, state, and local resource management agencies collected as many birds as possible for rescue and rehabilitation from the Long Beach Peninsula, WA; Fort Stevens State Beach, OR; and Cannon Beach, OR. Most of the birds collected were initially delivered to the Wildlife Center of the North Coast (WCNC) rehabilitation facility in Astoria, OR, where volunteers observed that birds were cold, weak, stressed, and starving. Due to the magnitude of this event, the WCNC facility was quickly overwhelmed by hundreds of collected seabirds, which included Common Loons (Gavia immer), Common Murres (Uria aalge), Pacific Loons (G. pacifica), Red-throated Loons (G. stellata), Surf Scoters (Melanitta perspicillata), and Western and Clark’s Grebes (Aechmophorus occidentalis and A. clarkii). Birds were subsequently transferred to facilities that were better equipped to handle large numbers of seabirds for rehabilitation, including the International Bird Rescue Research Center (IBRRC) in Cordelia, CA (n 5 479 birds), and Progressive Animal Welfare Society (PAWS) in Lynnwood, WA (n 5 125). Some birds responded well to supportive care and were eventually 1 We dedicate this manuscript to the men and women at US Coast Guard Air Station Sacramento, who donated their time and use of the C-130 Hercules aircraft to transport seabirds. This same Coast Guard aircraft crashed off the coast of San Diego, CA on 30 October 2009, within days of responding to the HAB event documented in this manuscript. All hands on board that aircraft were lost. We honor their memory and service. GENERAL NOTES

Modeling Low Rates of Seabird Bycatch in the U.S. Atlantic Longline Fishery

Total annual seabird bycatch in the U.S. Atlantic pelagic longline fishery was estimated from observer data by means of alternative methods to address the low frequency and uneven distribution of bird bycatch observations. Models used for estimation included generalized additive models (GAM), generalized linear models (GLM) and GLM with spatial or spatio-temporally auto correlated bycatch observations (s-GLM). Models were fitted separately to the probability of non-zero seabird capture (presence/absence) and to the numbers of seabirds per non-zero capture (positive bycatch); final estimates were obtained as the product of the two. Best-fitting models included latitude, longitude and quarter of year as covariates for presence/absence, and numbers of hooks per set for positive bycatch. Among the models compared, GLM gave the most consistent predictions of annual total seabird captures. For 2008, the most recent year modeled, GLM predicted 81 seabirds caught in 8,862 sets. The number is small on an Atlantic-wide or world-wide scale but is concentrated in an area of high species diversity that includes relatively small populations. GLM was recommended to be used in future Atlantic pelagic longline seabird bycatch estimation.

Seabird attendance and incidental mortality at shrimp fisheries in Golfo San Jorge, Argentina

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 432:125-135 (2011) - DOI: https://doi.org/10.3354/meps09146 Seabird attendance and incidental mortality at shrimp fisheries in Golfo San Jorge, Argentina Diego González-Zevallos1, Pablo Yorio1,2,*, Walter S. Svagelj1 1Centro Nacional Patagónico (CONICET), Blvd. Brown 2915, U9120ACD, Puerto Madryn, Chubut, Argentina 2Wildlife Conservation Society, Amenabar 1595, P 2, Of. 19, C1426AKC, Ciudad de Buenos Aires, Argentina *Corresponding author. Email: yorio@cenpat.edu.ar ABSTRACT: Many seabirds are attracted to trawl vessels to make use of fishery waste, and often this attraction results in increased incidental mortality. We assessed seabird attendance and associated incidental mortality at the Argentine red shrimp Pleoticus muelleri trawl fishery in Golfo San Jorge, Argentina. Information on seabird numbers was gathered in the autumn and winter 2006 and spring 2008, while information on seabird incidental captures was obtained for the period 2005–2007. Eighteen seabird species attended vessels, and the 2 most frequent and abundant seabirds (percent occurrence, median no. haul–1) were the kelp gull Larus dominicanus (>94%, <100) and black-browed albatross Thalassarche melanophrys (>94%, <55). Seabird numbers were significantly lower in winter than the other 2 seasons and highest during discarding activities. Species incidentally killed in nets were the Magellanic penguin Spheniscus magellanicus and imperial cormorant Phalacrocorax atriceps, with a mean capture rate of 0.048 birds haul–1, and for both species, mortality decreased with distance to the coast. Considering the fishery’s fishing effort during each month, the estimated total mortality in the study period was 895 (95% CI: 572 to 1339) penguins and 172 (95% CI: 69 to 305) cormorants. Over 95% of the recorded mortality occurred in 2005, the year when the trawling moratorium generally implemented in the area was not enforced. No interactions with warp cables were recorded. Results highlight the relevance of complying with the current moratorium scheme, as adjusting it to the penguin and cormorant breeding seasons may by a potentially effective management tool. The proximity to the coast of the recorded incidental mortalities indicates the need to re-evaluate the spatial design of the park and/or the definition of management actions beyond the boundaries of the Marine Protected Area. KEY WORDS: Seabird–fishery interactions · Seabird by-catch · Trawlers · Fishing discards · ­Patagonia Full text in pdf format PreviousNextCite this article as: González-Zevallos D, Yorio P, Svagelj WS (2011) Seabird attendance and incidental mortality at shrimp fisheries in Golfo San Jorge, Argentina. Mar Ecol Prog Ser 432:125-135. https://doi.org/10.3354/meps09146 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 432. Online publication date: June 27, 2011 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2011 Inter-Research.

Reflectance spectroscopy: a new approach for reconstructing penguin population size from Antarctic ornithogenic sediments

Reflectance spectroscopy has several advantages compared to traditional chemical methods in paleolimnology. It requires little cost, involves minimal or no sample preparation and is rapid. There has, however, been limited use of reflectance spectroscopy in polar paleolimnological studies. This paper explores the application of reflectance spectroscopy to reconstruct historical changes in penguin population size in the maritime Antarctic. Two ornithogenic sediment cores on Ardley Island, Antarctica were analyzed. Penguin droppings and weathered soils were analyzed as reference materials. Principal component analysis and linear mixing modeling were performed on the spectral data to estimate the proportion of penguin guano in the sediments and these values were used to infer historical penguin population numbers. Historical penguin population size versus time, reconstructed from reflectance spectra, and population numbers inferred from previous geochemical analysis of bio-elements, were quite similar. Our results illustrate the feasibility of rapidly inferring historical changes in penguin population size using reflectance spectroscopy on Antarctic ornithogenic sediments. Our findings suggest that this technique has potential for reconstructing past population numbers of other seabirds and mammals using lake sediments influenced by animal excrement.

Reducing interactions between seabirds and trawl fisheries: Responses to foraging patches provided by fish waste batches

Seabird bycatch in trawl fisheries is driven by the attraction of birds to foraging opportunities, i.e., the discharge of catch processing waste and the contents of trawl nets. The risk of seabird captures increases with seabird abundance and exposure to fishing gear. We investigated (1) how quickly seabirds responded to discharges of trawl catch processing waste and (2) whether decreasing numbers of seabirds attended trawlers during processing waste discharge events as the time interval between these events increased. Waste was retained onboard the vessel for four different holding periods (30 min, 2 h, 4 h, 8 h), one of which was applied each day using a randomised block design. We determined seabird responses to batch discharge events after the prescribed holding periods using the abundance of large (albatrossses and giant petrels Macronectes spp.) and small (all other petrels except cape petrels Daption capense, shearwaters and prions) seabirds in a semi-circle of 40 m radius, centred on the stern of the experimental trawler. Seabird responses reflected the type of discharge released: birds moved from the air to the water, as the amount of food available increased from no discharge, through sump discharge to batch discharge. When discharge occurred, seabird abundance increased faster than could be resolved with the 5 min sampling period. However, abundance decreased more slowly over a 10–15 min period after the discharge event. The number of large seabirds attending the vessel during discharge events decreased significantly when waste was held for 4 h. For small birds, significant decrease occurred after 8 h. Such holding periods emphasise the tenacity of foraging seabirds, although we have not evaluated any long-term habituation to a particular discharge regime. While holding waste for less than 4 h may not reduce seabird attendance during discharge events, holding for shorter intervals can still reduce bycatch risk, e.g., prior to and during net shooting and hauling.

Environmental impact assessment of offshore wind farms: a simulation‐based approach

Summary 1. Assessing and monitoring the impact of offshore wind farms on marine fauna is vital if we want to achieve ecologically sustainable development of this renewable energy resource. Given the complexity of the marine environment, a method capable of accommodating spatio‐temporal behaviour of specific species and their interrelation with other marine phenomena is an essential prerequisite for investigating whether or not there has been any measurable impact to date. 2. This paper presents a method based on geostatistical simulation to assess whether pre‐ and post‐construction collected bird count data suggest displacement of birds due to the wind farm. The method takes into account spatial autocorrelation in species abundance at various scales, pre‐ and post‐construction differences in environmental conditions and in survey effort and design. 3. We demonstrate that taking these factors into account influences the conclusions about a wind farm’s impact on bird life. In particular, incorporating spatial autocorrelation in seabird numbers is an important factor in reducing the risk of wrongly identifying an effect of a wind farm on bird abundance. 4. Synthesis and applications. The development of offshore wind farms is often in conflict with nature conservation interests. Environmental impact assessment and monitoring is essential to protect and manage the marine environment. The method described here will allow scarce data to be utilized effectively as a basis for well‐informed environmental decisions. In addition, the method will assist in the design of optimal monitoring procedures at a given site, balancing costs and effectiveness in detecting potentially harmful impacts.

The eradication of feral cats from Ascension Island and its subsequent recolonization by seabirds

The introduction of mammal predators to islands often results in rapid declines in the number and range of seabirds. On Ascension Island the introduction of cats in 1815 resulted in extirpation of large seabird colonies from the main island, with relict populations of most species persisting only in cat-inaccessible locations. We describe the eradication of feral cats from this large and populated island. The campaign had to minimize risk to humans and maintain domestic animals in a state that prevented them re-establishing a feral population. Feral cat numbers declined rapidly in response to the strategic deployment of poisoning and live trapping, and cats were eradicated from the island within 2 years. During the project 38% of domestic cats were killed accidentally, which caused public consternation; we make recommendations for reducing such problems in future eradications. Since the completion of the eradication campaign cat predation of adult seabirds has ceased and five seabird species have recolonized the mainland in small but increasing numbers. Breeding success of seabirds at Ascension was low compared to that of conspecifics elsewhere, and the roles of food availability, inexperience of parent birds and black rat predation in causing this warrant further investigation. It is likely that the low breeding success will result in the rate of increase in seabird populations being slow.

Estimates of numbers of kelp gulls and Kerguelen and Antarctic terns breeding at the Prince Edward Islands, 1996/1997–2008/2009

Breeding numbers of Laridae and other surface-nesting seabirds have been monitored at sub-Antarctic Marion Island since 1996/1997 and counts of breeding birds were made at nearby Prince Edward Island in December 2001 and December 2008. Four species are regular breeders at the islands: Subantarctic skua Catharacta antarctica, kelp gull Larus dominicanus, Antarctic tern Sterna vittata and Kerguelen tern S. virgata. The latter three species currently each have populations of below 150 breeding pairs at the islands. Kelp gull numbers appear to be relatively stable though they may have decreased since the 1980s. Kerguelen tern numbers decreased and then recovered at Marion Island, but numbers of the species have declined at Prince Edward Island and it maintains a tenuous foothold there. The small Antarctic tern population appears to be stable.

At-sea mortality of seabirds based on beachcast and offshore surveys

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 392:295-305 (2009) - DOI: https://doi.org/10.3354/meps08152 At-sea mortality of seabirds based on beachcast and offshore surveys Kelly M. Newton1,*, Donald A. Croll1, Hannahrose M. Nevins2, Scott R. Benson3, James T. Harvey2, Bernie R. Tershy1 1Center for Ocean Health, University of California Santa Cruz, 100 Shaffer Rd. Santa Cruz, California 95060, USA 2Moss Landing Marine Laboratories, 8272 Moss Landing Rd., Moss Landing, California 95039, USA 3NOAA Fisheries, 7544 Sandholdt Rd., Moss Landing, California 95039, USA *Email: newton.kelly@gmail.com ABSTRACT: Although seabird population biology is relatively well studied, little data exists on mortality at-sea. Beached bird surveys are used to identify patterns of seabird mortality, but resulting patterns are difficult to interpret without corresponding data on at-sea density. We examined seabird mortality relative to at-sea density in Monterey Bay, California over 10 yr by integrating data from monthly beachcast seabird and offshore seabird censuses. Beachcast seabird numbers were relatively constant (mean 2.82 ± 0.31 seabirds km–1) throughout the year. At-sea seabird density (mean 148.9 ± 16.12 seabirds km–2) peaked in the summer upwelling period and was least in the winter Davidson period. A principal components analysis of seasonal climatic, prey availability, and anthropogenic variables for Monterey Bay derived 3 significant principal components (PCs) (explaining 70% of variance) characterized by storm activity and low prey availability (PC1), river discharge and krill abundance (PC2), and oiling (PC3). These principal components were used in detailed analyses of the 2 most abundant seabird species and indicate that sooty shearwater Puffinus griseus relative mortality is greatest during decreased productivity and increased storm activity. While relative mortality of common murres Uria aalge cannot be explained by the derived principal components, relative mortality increased in late winter when prey availability decreased concurrent with the annual increase in reproductive stress. Beachcast seabird data is difficult to interpret in isolation; however, when linked to at-sea densities of seabirds, it becomes a powerful tool to examine the relative impacts of oceanography and direct human perturbations on seabird demography. KEY WORDS: Seabirds at-sea · Beached bird survey · Density · Mortality · Sooty shearwater · Common murre Full text in pdf format PreviousCite this article as: Newton KM, Croll DA, Nevins HM, Benson SR, Harvey JT, Tershy BR (2009) At-sea mortality of seabirds based on beachcast and offshore surveys. Mar Ecol Prog Ser 392:295-305. https://doi.org/10.3354/meps08152 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 392. Online publication date: October 19, 2009 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2009 Inter-Research.

Seabird bycatch in the pelagic longline fishery off southern Africa

The waters around South Africa provide rich foraging opportunities for pelagic seabirds. They also support a pelagic longline fleet targeting tunas Thunnus spp. and swordfish Xiphias gladius, which set a total of 41.5 million (average 5.2 million per year) and 10.2 million hooks (average 1.3 million per year) respectively during the period 1998-2005. Fisheries observers collected seabird bycatch data from 2 256 sets (4.4 million hooks) and recorded a total of 1 954 birds killed during that period. In all, 11 species of seabird are confirmed incidentally caught by the fishery, eight of which are considered threatened. Birds were caught at an average rate of 0.44 per 1 000 hooks, resulting in an average of 2 900 seabirds killed per year, decreasing from approximately 5 900 in 1998 to 1 800 in 2005. Three techniques for extrapolating total seabird mortality were investigated and little difference between the estimates found. Generalised linear models were used to explain bycatch patterns and revealed that individual vessel is the most important explanatory variable, followed by vessel flag, moon phase, season, sea state, the use of a tori line, time of set, area and bathymetry. Estimates of the numbers of seabirds killed per year were lower than other studies, an improvement most likely linked to the termination of foreign bilateral agreements, as well as to improved awareness among fishers as a result of ongoing education campaigns. Some of the apparent decreases in catch rate could reflect reduced numbers of seabirds at sea, the result of ongoing population decreases in several key species.

Major Conservation Policy Issues for Biodiversity in Oceania

Oceania is a diverse region encompassing Australia, Melanesia, Micronesia, New Zealand, and Polynesia, and it contains six of the world's 39 hotspots of diversity. It has a poor record for extinctions, particularly for birds on islands and mammals. Major causes include habitat loss and degradation, invasive species, and overexploitation. We identified six major threatening processes (habitat loss and degradation, invasive species, climate change, overexploitation, pollution, and disease) based on a comprehensive review of the literature and for each developed a set of conservation policies. Many policies reflect the urgent need to deal with the effects of burgeoning human populations (expected to increase significantly in the region) on biodiversity. There is considerable difference in resources for conservation, including people and available scientific information, which are heavily biased toward more developed countries in Oceania. Most scientific publications analyzed for four threats (habitat loss, invasive species, overexploitation, and pollution) are from developed countries: 88.6% of Web of Science publications were from Australia (53.7%), New Zealand (24.3%), and Hawaiian Islands (10.5%). Many island states have limited resources or expertise. Even countries that do (e.g., Australia, New Zealand) have ongoing and emerging significant challenges, particularly with the interactive effects of climate change. Oceania will require the implementation of effective policies for conservation if the region's poor record on extinctions is not to continue.

Resilience of the British and Irish seabird community in the twentieth century

AB Aquatic Biology Contact the journal Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AB 4:187-199 (2008) - DOI: https://doi.org/10.3354/ab00095 Resilience of the British and Irish seabird community in the twentieth century Marine Grandgeorge1,2, Sarah Wanless3, Timothy E. Dunn4, Myriam Maumy5, Grégory Beaugrand6, David Grémillet1,7,* 1Centre National de la Recherche Scientifique, Centre d’Ecologie Fonctionnelle et Evolutive, 1919 route de Mende, 34293 Montpellier, France2Centre National de la Recherche Scientifique, Laboratoire EthoS, Campus de Beaulieu, Bat 25, 263 avenue du Général Leclerc, 35042 Rennes, France 3Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian EH26 0QB, UK 4Joint Nature Conservation Committee, Dunnet House, 7 Thistle Place, Aberdeen AB10 1UZ, UK 5Laboratoire de Statistique, Université Louis Pasteur, 7 rue Descartes, 67084 Strasbourg, France 6Centre National de la Recherche Scientifique, Laboratoire d’Océanologie et de Géosciences, UMR LOG CNRS 8187, Station Marine, Université des Sciences et Technologies de Lille, 59000 Lille, France 7DST/NRF Centre of Excellence at the Percy FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch 7701, South Africa *Corresponding author. Email: david.gremillet@cefe.cnrs.fr ABSTRACT: We studied the British and Irish seabird community in the 20th century, a period of great anthropogenic impact. We determined the average body mass of community members and analysed population sizes, phylogenetic and spatial structures. We also quantified the total predation exerted by seabirds around Britain and Ireland and the spatial distribution of this predation in the North Sea. To achieve these aims we used (1) presence or absence of the seabird species in the different counties of Britain and Ireland between 1875 to 1900 and 1968 to 1972, (2) seabird breeding censuses of Britain and Ireland from 1969 to 1970, 1985 to 1988 and 1998 to 2002, (3) at-sea abundance and distribution surveys of seabirds in the North Sea from 1980 to 1985 and 1990 to 1995, and (4) a bioenergetics model to estimate energy expenditures for 40 seabird species. Our analyses suggest a marked expansion in the breeding range of seabirds in Britain and Ireland between 1875 and 1972. Total seabird numbers also increased at an average rate of 1% per annum between 1969 and 2002, with a related increase of 115% in predicted total seabird predation. Only terns Sternidae declined during this second period. Some characteristics of the community (geographical and phylogenetic structure, body mass) showed minor and non-significant variability between 1969 and 2002. Finally, seabird predation in the North Sea showed a slight north-eastward shift between 1980 to 1985 and 1990 to 1995. Overall, our study indicates that the seabird community of Britain and Ireland has prospered during the 20th century. These results contrast with extensive breeding failures recorded during the first years of the 21st century, which indicate that certain species within the community are now being critically disturbed. KEY WORDS: Bird phylogeny · Population census · Bioenergetics · Predation · Regime shift · Spatial analysis · Marine environment Full text in pdf format PreviousNextCite this article as: Grandgeorge M, Wanless S, Dunn TE, Maumy M, Beaugrand G, Grémillet D (2008) Resilience of the British and Irish seabird community in the twentieth century. Aquat Biol 4:187-199. https://doi.org/10.3354/ab00095Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AB Vol. 4, No. 2. Online publication date: December 02, 2008 Print ISSN: 1864-7782; Online ISSN: 1864-7790 Copyright © 2008 Inter-Research.

Effectiveness of fish waste management strategies in reducing seabird attendance at a trawl vessel

The risk of seabird bycatch in trawl fisheries is increased by high numbers of seabirds attending vessels to feed on fish waste discharged. We conducted an experimental test of whether mincing fish waste prior to its discharge from a factory trawler reduced the number of seabirds attending the vessel. The trial was conducted on a mid-water trawler targeting hoki ( Macruronus novaezelandiae) in New Zealand waters, and the experiment compared three treatments (1) discharging ‘unprocessed’ waste (fish offal and whole discards), (2) mincing all waste to a small particle size before discharge, or, (3) converting all waste to fishmeal and reducing discharge to sump water. The response to the experimental treatments was determined using seabird abundance within a 40 m-radius semi-circular area centred on the vessel stern. Mincing reduced the numbers of large albatrosses ( Diomedea spp.) feeding astern of the vessel, but had no significant effect on other groups of seabirds. In contrast, reducing discharge to sump water resulted in a significant reduction in numbers of all groups of seabirds. In particular, the abundance of the small albatross group (principally Thalassarche spp.), and some smaller procellarids (e.g. sooty shearwater, Puffinus griseus, and white-chinned petrel, Procellaria aequinoctialis), was reduced to less than five percent of the number that were within the sweep area when unprocessed discharge was released. While mincing significantly reduced the abundance of large albatrosses at the vessel stern, relatively small numbers of these birds attend trawl vessels in New Zealand waters and associated bycatch rates are low. In contrast, reducing the quantity of fish waste discharge by mealing resulted in reduced abundances of a wide range of seabirds at the vessel. Therefore, compared to mincing, we recommend fish waste retention as a more effective management strategy for reducing seabird bycatch.

Annual survival of North American Razorbills (Alca torda) varies with ocean climate indices

According to life-history theory, survival in long-lived animals is not expected to vary greatly with environmental conditions. However, recent studies of a number of seabirds have shown that ocean climate indices such as the Pacific Decadal Oscillation index and sea surface temperature are correlated with adult survival. Here we evaluated whether annual adult survival of Razorbills ( Alca torda L., 1758) at two breeding colonies covaried with oceanographic conditions in the North Atlantic during 1995–2006. We also examined pre-breeder survival (from fledging to age 2). The relationship between local adult survival and the North Atlantic Oscillation and two oceanographic variables (Labrador Current temperature profile and Bay of Fundy sea surface temperature) were evaluated using the program MARK. Capture–mark–recapture data fit the assumptions of the program MARK reasonably well with ĉ values ranging from 1.390 to 2.404. Pre-breeder survival rates were high for Machias Seal Island (Ф = 0.778 ± 0.041) and low for the Gannet Islands (Ф = 0.482 ± 0.033), likely the result of hunting pressure. On Machias Seal Island, constant adult survival (Ф = 0.967 ± 0.028) was the best model; however, time-dependent models that included a climate covariate performed nearly as well. On the Gannet Islands, adult survival (Ф = 0.890 ± 0.053) was negatively correlated with Labrador Current temperature. Overall, our results show significant differences in survival rates across sites over the same time period and highlight the importance of multisite studies and smaller scale climate indices for local populations. In addition, our study contributes to the growing body of evidence that survival in long-lived animals may vary with environmental conditions more than previously expected.