Richard Sears

Genetic tagging of humpback whales

The ability to recognize individual animals has substantially increased our knowledge of the biology and behaviour of many taxa. However, not all species lend themselves to this approach, either because of insufficient phenotypic variation or because tag attachment is not feasible. The use of genetic markers (‘tags’) represents a viable alternative to traditional methods of individual recognition, as they are permanent and exist in all individuals. We tested the use of genetic markers as the primary means of identifying individuals in a study of humpback whales in the North Atlantic Ocean. Analysis of six microsatellite loci, among 3,060 skin samples collected throughout this ocean allowed the unequivocal identification of individuals. Analysis of 692 ‘recaptures’, identified by their genotype, revealed individual local and migratory movements of up to 10,000 km, limited exchange among summer feeding grounds, and mixing in winter breeding areas, and also allowed the first estimates of animal abundance based solely on genotypic data. Our study demonstrates that genetic tagging is not only feasible, but generates data (for example, on sex) that can be valuable when interpreting the results of tagging experiments.

Population genetic structure of North Atlantic, Mediterranean Sea and Sea of Cortez fin whales, Balaenoptera physalus (Linnaeus 1758): analysis of mitochondrial and nuclear loci

Samples were collected from 407 fin whales, Balaenoptera physalus, at four North Atlantic and one Mediterranean Sea summer feeding area as well as the Sea of Cortez in the Pacific Ocean. For each sample, the sex, the sequence of the first 288 nucleotides of the mitochondrial (mt) control region and the genotype at six microsatellite loci were determined. A significant degree of divergence was detected at all nuclear and mt loci between North Atlantic/Mediterranean Sea and the Sea of Cortez. However, the divergence time estimated from the mt sequences was substantially lower than the time elapsed since the rise of the Panama Isthmus, suggesting occasional gene flow between the North Pacific and North Atlantic ocean after the separation of the two oceans. Within the North Atlantic and Mediterranean Sea, significant levels of heterogeneity were observed in the mtDNA between the Mediterranean Sea, the eastern (Spain) and the western (the Gulf of Maine and the Gulf of St Lawrence) North Atlantic. Samples collected off West Greenland and Iceland could not be unequivocally assigned to either of the two areas. The homogeneity tests performed using the nuclear data revealed significant levels of divergence only between the Mediterranean Sea and the Gulf of St Lawrence or West Greenland. In conclusion, our results suggest the existence of several recently diverged populations in the North Atlantic and Mediterranean Sea, possibly with some limited gene flow between adjacent populations, a population structure which is consistent with earlier population models proposed by Kellogg, Ingebrigtsen, and Sergeant.

Adapting to a Warmer Ocean—Seasonal Shift of Baleen Whale Movements over Three Decades

Global warming poses particular challenges to migratory species, which face changes to the multiple environments occupied during migration. For many species, the timing of migration between summer and winter grounds and also within-season movements are crucial to maximise exploitation of temporarily abundant prey resources in feeding areas, themselves adapting to the warming planet. We investigated the temporal variation in the occurrence of fin (Balaenoptera physalus) and humpback whales (Megaptera novaeangliae) in a North Atlantic summer feeding ground, the Gulf of St. Lawrence (Canada), from 1984 to 2010 using a long-term study of individually identifiable animals. These two sympatric species both shifted their date of arrival at a previously undocumented rate of more than 1day per year earlier over the study period thus maintaining the approximate 2-week difference in arrival of the two species and enabling the maintenance of temporal niche separation. However, the departure date of both species also shifted earlier but at different rates resulting in increasing temporal overlap over the study period indicating that this separation may be starting to erode. Our analysis revealed that the trend in arrival was strongly related to earlier ice break-up and rising sea surface temperature, likely triggering earlier primary production. The observed changes in phenology in response to ocean warming are a remarkable example of phenotypic plasticity and may partly explain how baleen whales were able to survive a number of changes in climate over the last several million years. However, it is questionable whether the observed rate of change in timing can be maintained. Substantial modification to the distribution or annual life cycle of these species might be required to keep up with the ongoing warming of the oceans.

Polymorphic microsatellite loci isolated from humpback whale, Megaptera novaeangliae and fin whale, balaenoptera physalus

Key words: baleen whale, kinship, Mysteceti, STR lociInconservationgenetics,itisbecomingincreasinglyclear that parameters derived over evolutionarytime scales may not apply to much shorter ecolog-ical timescales (Palsboll 1999). Molecular geneticmethods can be employed to estimate parametersonanecological timescale ifthe focusis aimedonlyat recently diverged lineages, i.e., among individu-als as opposed to among populations. Theseextensions of current approaches are vital to alignthe application of molecular genetics to contem-porary issues in conservation. In order to estimatethe degree of kinship in a reliable manner, an ade-quate number of loci must be analyzed per indi-vidual. Ensuring an adequate number of locidecreases/eliminates the interference of other levelsof relatives, and compensates for the exponentialincrease in the number of pair-wise comparisonswhen the sample size increases. Towards this end,we presented, in this note, an additional 17 poly-morphic microsatellite loci, which, originated froma di-, tri- and tetra-nucleotide microsatellite locienriched library constructed from humpbackwhale, Megaptera novaeangliae, and fin whale,Balaenoptera physalus, genomic DNA, using theprotocol previously described in Palsboll et al.(1997) and Be´rube´et al. (2000).More specifically, the microsatellite loci wereisolated from size-selected total-cell DNAextracted from humpback whale and fin whaleusing the approach described by Rassmann andcolleagues (1991). Recombinant colonies (dotblotted to a ZetaProbe

The Usefulness of Parallel Analysis of Uni- and Bi-Parental Markers: The North Atlantic Humpback Whale

The majority of studies of the evolution and structure of animal populations are based upon analysis of either mitochondrial (mt) or nuclear DNA. Although each genome provides unique information, the combined results from parallel analyses of the two genomes can uncover additional facts that would otherwise have escaped detection.

Aerial behavior by the fin whale (Balaenoptera physalus) in the wake of a freighter and near other boats

This study confirms that the fin whale (Balaenoptera physalus) exhibits infrequent aerial behavior and that it sometimes occurs near different types of boats. We describe this uncommon behavior in the wake of a freighter and near other boats, provide details that expand upon an aerial rotation technique briefly noted in fin whales by others, and show that we have observed only three of these aerial events in 33 years of seasonal effort within our study areas in the Gulf of St. Lawrence, Canada. Collectively our study contributes new information, including kinematics, about aerial behavior in fin whales and suggests that this behavior is not geographically limited to the Mediterranean Sea where it has been reported most often.

Detection of a unique calling pattern during the respiratory cycle of blue whale pairs

Although blue whales are known for their long (10–20 s) low‐frequency (<20 Hz) vocalizations that occur in regularly patterned series, in coastal waters they produce short (1–4 s) higher‐frequency (30–150 Hz) unpatterned calls just as often. Paul Thompson was among the group of scientists who first attributed these short calls to blue whales. They found the majority of these calls to be downswept in frequency but noted the presence of others that were not. This paper describes a special patterning of these non‐downswept sounds that was detected in the St. Lawrence estuary in both 2000 and 2001. This patterning is variable but normally includes both regularly and irregularly spaced components. In at least a dozen cases, these mixed‐pattern bouts were detected in the presence of a pair of blue whales at the surface for their respiratory cycle. Characterization of these bouts and their daily, seasonal, and spatial distributions will be presented and compared with the distributions of the short downsweeps and...

St. Lawrence blue whale (Balaenopteramusculus) vocalizations

The Mingan Island Cetacean Study has been conducting biological field research on St. Lawrence blue whales since 1979. Currently, they have photo‐identified 384 individuals and determined the gender of 37% through skin biopsy sampling. In a typical field season, approximately 85% of the 60–90 blue whales identified have been seen before, so a larger percentage (65%) have known gender. During four field seasons (1998–2001), 134 h of acoustic recordings were made in the presence of this well‐studied population of blue whales. A calibrated omni‐directional hydrophone, suspended from a surface isolation buoy, was deployed from an inflatable boat positioned close to the whales. Simultaneous visual observations were made during the recording sessions, with individual identities confirmed through photo‐identification work between sessions. The primary field site for this project was the lower estuary region of the St. Lawrence River, with most recordings made between mid‐August and late October. Both infrasonic ...