Combination of the targeted amplification of nuclear introns and the analysis of single-stranded conformational polymorphisms has the potential to provide an inexpensive, rapid, versatile and sensitive genetic assay for evolutionary studies and conservation. We are developing primers and protocols to analyse nuclear introns in vertebrates, and are testing them in a population genetic study of marbled murrelets Brachyramphus marmoratus. Here we present protocols and results for introns for aldolase B, alpha-enolase, glyceraldehyde-3-phosphate dehydrogenase and lamin A. Results suggest that this approach presents a potentially powerful method for detecting genetic variation within and among local populations and species of animals: (i) a variety of genes can be surveyed, including genes of special interest such as those involved in disease resistance; (ii) assays are rapid and relatively inexpensive; (iii) large numbers of genes can be assayed, enabling accurate estimation of variation in the total genome; (iv) almost any mutation can be detected in the genes amplified; (v) the exact nature of variation can be investigated by sequence analysis if desired; (vi) statistical methods previously developed for proteins and/or sequence data can be used; (vii) protocols can be easily transferred to other species and other laboratories; and (viii) assays can be performed on old or degraded samples, blood or museum skins, so that animals need not be killed. Results of analyses for murrelets support earlier evidence that North American and Asiatic subspecies represent reproductively isolated species, and that genetic differences exist among murrelets from different sites within North America.

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To sustain breeding while simultaneously compensating for poor local resource availability, many temperate Procellariiformes (tube-nosed seabirds) access highly productive areas 'atdistance' from breeding colonies using a unique dual-foraging strategy. We tested for, and observed, a similar dual foraging strategy in a tropical Procellariiform, the wedge-tailed shearwater Puffinus pacificus. Foraging adults repeatedly performed short-trip cycles of multiple 1 to 4 d trips followed by a single long-trip of ~8 d. As with temperate species, wedge-tailed shearwaters used long-trips to build body reserves that they passed onto chicks by not self-provisioning adequately during the early stages of each short-trip cycle. Unlike temperate species (1) long-trip length and adult mass change during long-trips was inversely related to adult mass at the beginning of the same long-trip, and (2) foraging mode changeover appeared to be co-ordinated and was not initiated by adults reaching some critical lower mass. This implies that the dual-foraging pattern observed in wedge-tailed shearwaters is a consequence of the median time adults require to replenish body reserves on long-trips. We conclude that foraging strategies in wedge-tailed shearwaters vary spatially relative to nearcolony resource availability, and that dual-foraging is a general Procellariiform life-history strategy used to address similar ecological constraints in both temperate and tropical systems. Our findings suggest that wedge-tailed shearwaters of the southern Great Barrier Reef (GBR) may be dependent on localised areas of high productivity 'at-distance' from breeding colonies to sustain breeding.KEY WORDS: Dual-foraging · Co-ordinated provisioning · Feeding ecology · Wedge-tailed shearwater · Puffinus pacificus · Procellariiform · Great Barrier Reef Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 301: [293][294][295][296][297][298][299][300][301] 2005 that dual-foraging can be unambiguously linked to the use of distant highly productive foraging areas in these species.Tropical Procellariiformes face similar energetic constraints, yet it is unlikely that they consistently access the same highly productive temperate waters to compensate for poor local resource availability. This is particularly true of the smaller pan-tropically distributed Procellariiform species, such as the wedge-tailed shearwater Puffinus pacificus. How then do tropical species replenish their own reserves while simultaneously satisfying chick requirements? Two possibilities exist. Firstly, tropical Procellariiformes may use a dualforaging strategy similar to temperate species to access currently unknown, highly productive but more localised foraging zones in the tropics. Limited evidence for this possibility exists. Phoebastria immutabilis (Laysan albatross) and P. nigripes (black-footed albatross) nesting in the subtropics at Tern Island, French Frigate Shoals, Hawaii, both have bimodal foraging trip durations similar to tempe...

Processes that underlie impacts of global warming on marine organisms at upper trophic levels are largely unknown. Long-term studies of seabirds indicate that inter-annual decreases in fledging success are correlated with El Niño years, when sea surface temperatures (SSTs) are above long-term averages. These studies propose that seasonal processes are most likely responsible. To date, no work has focused on the potential impacts of elevated SSTs on seabird reproduction at finer time scales, i.e. within a breeding season. We directly measured the influence of SST variability on foraging success in the wedge-tailed shearwater Puffinus pacificus within and among 3 breeding seasons at Heron Island in the southern Great Barrier Reef, Australia. We found that changes in foraging success (meal size and feed frequency) and chick growth were negatively correlated with daily variations in SST both within and among seasons. Our findings suggest that forage resource availability fluctuated daily in direct association with small-scale variation in SST. This is evidence that declines in seabird breeding success, previously coupled exclusively with large-scale El Niño conditions and processes, may also involve fine-scale mechanisms. Consequently, observed El Niño scale impacts may include season-specific outcomes of day-to-day trophic interactions that operate within all breeding seasons.

Although there is growing evidence of climate warming, for many regions the broader effects of climate variation on marine top predators remains unknown owing to the difficulty in obtaining, for synthesis, long-term and shortterm datasets on multiple species. In the Australian region, climatic and oceanographic variability and change have been shown to affect marine species, often with profound consequences. Many seabirds are apex predators for which changes in climatic and oceanic dynamics have driven range movements poleward, reduced breeding success and altered breeding timing for some species. Here we review the literature to assess and determine the vulnerability of Australian seabirds to variation and change in climate and identify which species and ecosystems may be more resilient to future climate warming. It is clear from this synthesis that not all Australian seabirds are affected similarly, with responses varying by species and location. In addition, the paucity of information on the distribution and biology of seabird prey, foraging patterns and movements of seabirds, and the ability of seabirds to switch between prey species or adjust timing of life-cycles make generalisations about potential effects of future climate change and adaptive capacity in seabirds difficult. This applies both within Australia and elsewhere, where data are similarly sparse.

Humpback whales (Megaptera novaeangliae) annually undertake the longest migrations between seasonal feeding and breeding grounds of any mammal. Despite this dispersal potential, discontinuous seasonal distributions and migratory patterns suggest that humpbacks form discrete regional populations within each ocean. To better understand the worldwide population history of humpbacks, and the interplay of this species with the oceanic environment through geological time, we assembled mitochondrial DNA control region sequences representing approximately 2700 individuals (465 bp, 219 haplotypes) and eight nuclear intronic sequences representing approximately 70 individuals (3700 bp, 140 alleles) from the North Pacific, North Atlantic and Southern Hemisphere. Bayesian divergence time reconstructions date the origin of humpback mtDNA lineages to the Pleistocene (880 ka, 95% posterior intervals 550-1320 ka) and estimate radiation of current Northern Hemisphere lineages between 50 and 200 ka, indicating colonization of the northern oceans prior to the Last Glacial Maximum. Coalescent analyses reveal restricted gene flow between ocean basins, with long-term migration rates (individual migrants per generation) of less than 3.3 for mtDNA and less than 2 for nuclear genomic DNA. Genetic evidence suggests that humpbacks in the North Pacific, North Atlantic and Southern Hemisphere are on independent evolutionary trajectories, supporting taxonomic revision of M. novaeangliae to three subspecies.

.— Mechanisms of population differentiation in highly vagile species such as seabirds are poorly understood. Previous studies of marbled murrelets (Brachyramphus marmoratus; Charadriiformes: Alcidae) found significant population genetic structure, but could not determine whether this structure is due to historical vicariance (e.g., due to Pleistocene glaciers), isolation by distance, drift or selection in peripheral populations, or nesting habitat selection. To discriminate among these possibilities, we analyzed sequence variation in nine nuclear introns from 120 marbled murrelets sampled from British Columbia to the western Aleutian Islands. Mismatch distributions indicated that murrelets underwent at least one population expansion during the Pleistocene and probably are not in genetic equilibrium. Maximum‐likelihood analysis of allele frequencies suggested that murrelets from “mainland” sites (from the Alaskan Peninsula east) are genetically different from those in the Aleutians and that these two lineages diverged prior to the last glaciation. Analyses of molecular variance, as well as estimates of gene flow derived using coalescent theory, indicate that population genetic structure is best explained by peripheral isolation of murrelets in the Aleutian Islands, rather than by selection associated with different nesting habitats. No isolation‐by‐distance effects could be detected. Our results are consistent with a rapid expansion of murrelets from a single refugium during the early–mid Pleistocene, subsequent isolation and divergence in two or more refugia during the final Pleistocene glacial advance, and secondary contact following retreat of the ice sheets. Population genetic structure now appears to be maintained by distance effects combined with small populations and a highly fragmented habitat in the Aleutian Islands.