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Intrinsic population growth rate ( rmax) is an important parameter for many ecological applications, such as population risk assessment and harvest management. However, rmax can be a difficult parameter to estimate, particularly for long-lived species, for which appropriate life table data or abundance time series are typically not obtainable. We describe a method for improving estimates of rmax for long-lived species by integrating life-history theory (allometric models) and population-specific demographic data (life table models). Broad allometric relationships, such as those between life history traits and body size, have long been recognized by ecologists. These relationships are useful for deriving theoretical expectations for rmax, but rmax for real populations may vary from simple allometric estimators for 'archetypical' species of a given taxa or body mass. Meanwhile, life table approaches can provide population-specific estimates of rmax from empirical data, but these may have poor precision from imprecise and missing vital rate parameter estimates. Our method borrows strength from both approaches to provide estimates that are consistent with both life-history theory and population-specific empirical data, and are likely to be more robust than estimates provided by either method alone. Our method uses an allometric constant: the product of rmax and the associated generation time for a stable-age population growing at this rate. We conducted a meta-analysis to estimate the mean and variance of this allometric constant across well-studied populations from three vertebrate taxa (birds, mammals, and elasmobranchs) and found that the mean was approximately 1.0 for each taxon. We used these as informative Bayesian priors that determine how much to 'shrink' imprecise vital rate estimates for a data-limited population toward the allometric expectation. The approach ultimately provides estimates of rmax (and other vital rates) that reflect a balance of information from the individual studied population, theoretical expectation, and meta-analysis of other populations. We applied the method specifically to an archetypical petrel (representing the genus Procellaria ) and to white sharks ( Carcharodon carcharias) in the context of estimating sustainable fishery bycatch limits. [ABSTRACT FROM AUTHOR]

ABSTRACT The large midden site of Offing 2 (southern Chile) has yielded a series of human occupations dating back to 4200-2500 bp. From a very large collection of bird specimens, we sampled over 45 000 bird bones from four taxa ( Diomedea sp., Procellaria sp., Phalacrocorax sp. and Sterna hirundinacea). The distributions of skeletal parts do not contradict the bone density and functional anatomy hypotheses for cormorants and terns, but the observed data for albatross and petrel are less convincing. The presence of most or all elements (except for the terns) indicates that the birds were brought back to the site as complete carcasses. The deficit of some of the long wing bones observed for albatross and petrel is remarkable and may indicate a particular removal for later use as raw material for tools or trade goods. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Concentrations of copper (Cu), zinc (Zn), cadmium (Cd), lead (Pb), mercury (Hg), and selenium (Se) were determined in blood and feathers of spectacled ( Procellaria conspicillata) and white-chinned ( Procellaria aequinoctialis) petrels, species that are phylogenetically related, but with distinct ecological niches. In winter, they feed on similar foods, indicated by an overlapping range of whole-blood stable isotopes values (δ15N; δ13C). No relation was found between blood metal concentration and stable isotope values. In spectacled petrels, metal concentrations appeared lower in blood (Cu = 0.79-20.77 µg/g; Zn = 10.95-28.02 µg/g; Cd = 1.73-10.11 µg/g; Pb = 5.02-26.03 µg/g; Hg = 0.84-9.86 µg/g) than in feathers (Cu = 1.05-21.57 µg/g; Zn = 45.30-81.49 µg/g; Cd = 3.76-10.44 µg/g; Pb = 16.53-59.00 µg/g; Hg = 4.24-24.03 µg/g). In white-chinned petrels, metal concentrations also appeared lower in blood (Cu = 0.62-10.4 µg/g; Zn = 10.73-24.69 µg/g; Cd = 2.00-6.31 µg/g; Pb = 5.72-24.03 µg/g) than in feathers (Cu = 2.68-23.92 µg/g; Zn = 48.96-93.54 µg/g; Cd = 5.72-24.03 µg/g; Pb = 18.62-55.51 µg/g), except for Hg (blood = 0.20-15.82 µg/g; feathers = 0.19-8.91 µg/g). Selenium (0.24-14.18 µg/g) and Hg (0.22-1.44 µg/g) concentrations showed a positive correlation in growing feathers of spectacled petrels. Blood and feather Hg levels were higher in spectacled petrels while feathers Cu and Zn concentrations were greater in white-chinned petrels. Juvenile white-chinned petrels exhibited greater blood Hg concentrations than adults. In the south Atlantic Ocean, discards from commercial fishing operations consumed by spectacled petrels year-round and by white-chinned petrels during the wintering period have elevated Hg concentrations. Because Hg toxicity is associated with behavioral and reproductive changes in birds, it could potentially have impacts on breeding of these seabirds, as both species are listed as threatened by extinction. Environ Toxicol Chem 2013;32:1641-1648. © 2013 SETAC [ABSTRACT FROM AUTHOR]

White-chinned petrels Procellaria aequinoctialis and grey petrels Procellaria cinerea are among the most frequently killed seabird species by accidental bycatch, and both species have received strong conservation concern. Data on population size are required to evaluate the impact of bycatch and to establish management plans. We estimated the population size of both species at Kerguelen, Southern Indian Ocean, from 2004 to 2006 by explicitly taking into account detection probability of burrows using distance sampling and burrow occupancy. A total of 31 line-transects were distributed across the eastern part of Kerguelen, representing a total length of 566 km. Detectability was low (from 0.19 to 0.54 for white-chinned petrels, 0.58 for grey petrels). Burrow densities varied from 1.37±0.67 to 25.77±5.23 burrows ha−1 for white-chinned petrels and was 2.78±0.79 burrows ha−1 for grey petrels. For white-chinned petrels, these densities were extrapolated to the entire surface area of vegetation and there were 234 000 (186 000–297 000) active burrows on Kerguelen. For grey petrels, the number of active burrows for the eastern part of Kerguelen was 3400 (1900–5600). Based on these estimates, the potential biological removal method suggests that the additional mortality on birds caused by the fisheries operating around Kerguelen can be considered a serious threat for the species at least at the regional scale of the Southern Indian Ocean, especially for grey petrels. [ABSTRACT FROM AUTHOR]

1. Fisheries can affect non-target species through bycatch, and climate change may act simultaneously on their population dynamics. Estimating the relative impact of fisheries and climate on non-target species remains a challenge for many populations because the spatio-temporal distribution of individuals remains poorly known and available demographic information is incomplete. 2. We used population survey data, capture–mark–recapture methods, population modelling and the demographic invariant method to investigate the effects of climate and fisheries on the demography of a predator species affected by bycatch. These complementary approaches were used to help account for different sources of uncertainty. 3. The white-chinned petrel Procellaria aequinoctialis is the commonest seabird species killed by longline fisheries in the Southern Ocean. Petrel breeding success was positively related to the fishing effort for Patagonian toothfish Dissosticus eleginoides. El Niño events negatively affected adult survival with a time lag of 3 years. Fishing efforts for toothfish and hake ( Merluccius spp.) were negatively related to petrel recruitment, suggesting that fisheries-induced mortality strongly impacted younger age classes. Lambda estimated from matrix population models was below replacement (0·964 ± 0·026), and the number of breeding pairs declined by ≈ 37% in 21 years. This decline was probably caused by low survival of both young age classes and adults. 4. The Crozet archipelago, Southern Indian Ocean, population size was estimated at ≈ 170 000 individuals in the early 1980s, and would be severely affected by any additional source of mortality that approached 8000 individuals per year. The number of petrels killed by the toothfish fishery alone exceeded this threshold during the late 1990s and early 2000s, but has declined well below this since 2003. 5. Synthesis and applications. Complementary approaches suggest that both longline fishery bycatch and climate have a significant impact on the size of the Southern Ocean white-chinned petrel population. Stopping or reversing climate change will be a very slow process, and may be impossible. Therefore, we recommend a reduction in bycatch to help the populations recover. Further information on the status of individuals caught in longlines is required to understand the demographic processes involved. [ABSTRACT FROM AUTHOR]