The fin whale Balaenoptera physalus (L. 1758) in the Mediterranean Sea

1. The ecology and status of fin whales Balaenoptera physalus in the Mediterranean Sea is reviewed. The species’ presence, morphology, distribution, movements, population structure, ecology and behaviour in this semi‐enclosed marine region are summarized, and the review is complemented with original, previously unpublished data. 2. Although the total size of the fin whale population in the Mediterranean is unknown, an estimate for a portion of the western basin, where most of the whales are known to live, was approximately 3500 individuals. High whale densities, comparable to those found in rich oceanic habitats, were found in well‐defined areas of high productivity. Most whales concentrate in the Ligurian‐Corsican‐Provençal Basin, where their presence is particularly noticeable during summer; however, neither their movement patterns throughout the region nor their seasonal cycle are clear. 3. Based on genetic studies, fin whales from the Mediterranean Sea are distinct from North Atlantic conspecifics, and may constitute a resident population, separate from those of the North Atlantic, despite the species’ historical presence in the Strait of Gibraltar. Fin whales are known to calve in the Mediterranean, with births peaking in November but occurring at lower rates throughout the year. They feed primarily on krill Meganyctiphanes norvegica which they capture by diving to depths in excess of 470 m. It is suggested that the extensive vertical migratory behaviour of its main prey may have influenced the social ecology of this population. 4. Known causes of mortality and threats, including collisions with vessels, entanglement in fishing gear, deliberate killing, disturbance, pollution and disease, are listed and discussed in view of the implementation of appropriate conservation measures to ensure the species’ survival in the region.     

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.     

Female philopatry in coastal basins and male dispersion across the North Atlantic in a highly mobile marine species, the sperm whale (Physeter macrocephalus)

The mechanisms that determine population structure in highly mobile marine species are poorly understood, but useful towards understanding the evolution of diversity, and essential for effective conservation and management. In this study, we compare putative sperm whale populations located in the Gulf of Mexico, western North Atlantic, Mediterranean Sea and North Sea using mtDNA control region sequence data and 16 polymorphic microsatellite loci. The Gulf of Mexico, western North Atlantic and North Sea populations each possessed similar low levels of haplotype and nucleotide diversity at the mtDNA locus, while the Mediterranean Sea population showed no detectable mtDNA diversity. Mitochondrial DNA results showed significant differentiation between all populations, while microsatellites showed significant differentiation only for comparisons with the Mediterranean Sea, and at a much lower level than seen for mtDNA. Samples from either side of the North Atlantic in coastal waters showed no differentiation for mtDNA, while North Atlantic samples from just outside the Gulf of Mexico (the western North Atlantic sample) were highly differentiated from samples within the Gulf at this locus. Our analyses indicate a previously unknown fidelity of females to coastal basins either side of the North Atlantic, and suggest the movement of males among these populations for breeding.     

Synchronous Seasonal Change in Fin Whale Song in the North Pacific

Fin whale (Balaenoptera physalus) song consists of down-swept pulses arranged into stereotypic sequences that can be characterized according to the interval between successive pulses. As in blue (B. musculus) and humpback whales (Megaptera novaeangliae), these song sequences may be geographically distinct and may correlate with population boundaries in some regions. We measured inter-pulse intervals of fin whale songs within year-round acoustic datasets collected between 2000 and 2006 in three regions of the eastern North Pacific: Southern California, the Bering Sea, and Hawaii. A distinctive song type that was recorded in all three regions is characterized by singlet and doublet inter-pulse intervals that increase seasonally, then annually reset to the same shorter intervals at the beginning of each season. This song type was recorded in the Bering Sea and off Southern California from September through May and off Hawaii from December through April, with the song interval generally synchronized across all monitoring locations. The broad geographic and seasonal occurrence of this particular fin whale song type may represent a single population broadly distributed throughout the eastern Pacific with no clear seasonal migratory pattern. Previous studies attempting to infer population structure of fin whales in the North Pacific using synchronous individual song samples have been unsuccessful, likely because they did not account for the seasonal lengthening in song intervals observed here.     

Song sharing and diversity in the Bering‐Chukchi‐Beaufort population of bowhead whales (Balaena mysticetus), spring 2011

Bowhead whales (Balaena mysticetus) of the Bering‐Chukchi‐Beaufort population migrate in nearshore leads through the Chukchi Sea each spring to summering grounds in the Beaufort Sea. As part of a population abundance study, hydrophones were deployed in the Chukchi Sea off Point Barrow, (12 April to 27 May 2011) and in the Beaufort Sea (12 April to 30 June 2011). Data from these sites were analyzed for the presence of bowhead whale song. We identified 12 unique song types sung by at least 32 individuals during ~95 h of recordings off Point Barrow. Six of these songs were detected at the Beaufort MARU site as well as six additional song types that were not analyzed. These results suggest a shared song repertoire among some individuals. This report represents the greatest number of songs to date during the spring migration for this population. We attribute this greater variety to population growth over the 30 yr since acoustic monitoring began in the early 1980s. Singing during early to mid‐spring is consistent with the hypothesis that song is a reproductive display, but further research is necessary to understand the exact function of this complex vocal behavior.     

Blue and fin whale acoustic presence around Antarctica during 2003 and 2004

Seasonal and spatial variations of blue ( Balaenoptera musculus ) and fin whale ( B. physalus ) calls were analyzed from recordings collected with Acoustic Recording Packages (ARPs) deployed between January 2003 and July 2004 at four circumpolar locations: the Western Antarctic Peninsula (WAP), the Scotia Sea (SS), Eastern Antarctica (EA), and the Ross Sea (RS). Call characteristics were compared among sites using the average pressure spectrum levels from 1 month of data at each location. Presence of calls was analyzed using automatic call detection and acoustic power analysis methods. Blue whale calls were recorded year-round, with the highest detections in February–May and November. This suggests that the blue whale population may not migrate synchronously, and may indicate long duration calls are more common during migrations. Fin whale calls were detected only during February–July. Two distinct fin whale call types were recorded, suggesting a possible separation into two populations. The calls at the EA site had a secondary frequency peak in the pressure spectrum at 99 Hz and the calls at the WAP and the SS sites had a peak at 89 Hz. No fin whale calls were detected at the RS site. Acoustics are a good tool to monitor large whales in the Southern Ocean.     

OPEN-BOAT WHALING ON THE STRAITS OF GIBRALTAR GROUND AND ADJACENT WATERS

Logbooks ( n = 317) from whaling expeditions made in the North Atlantic during the 19th century were examined to investigate activity in the Gibraltar Straits grounds. At least forty expeditions of whaling vessels from European and American ports visited the area. In all cases the main target was the sperm whale, but pilot whales, dolphins, sea turtles, and even a blue whale were also taken. Whaling effort concentrated on the Atlantic side of the Straits; only two expeditions ventured into the Mediterranean Sea, obtaining negligible catches. The whaling season extended during spring and summer and peaked in June–July. This seasonality appeared not to be governed by changes in whale density but by the trade winds necessary to sail southward or westward to cross the Atlantic. Searching effort continued while trying out, but the rate of sighting cetaceans was about half that of searching periods. However, the rate of sighting or capturing a sperm whale remained unchanged during processing, probably because the gregarious habits of the species produced clumping of catches. For every whale secured, 1.31 whales were struck. After correcting for struck but lost whales and for "gammed" vessels, the minimum number of removals of sperm whales during 1862–1889 is estimated at 237.     

Quantifying spatial and temporal variation of North Pacific fin whale (Balaenoptera physalus) acoustic behavior

In order to help develop hypotheses of connectivity among North Pacific fin whales, we examine recordings from 10 regions collected in the spring and fall. We develop a Random Forest model to classify fin whale note types that avoids manual note classification errors. We also present a method that objectively quantifies the note and pattern composition of recordings. We find that fin whale recordings near Hawaii have distinctive patterns, similar to those found in other regions in the central North Pacific, suggesting potential migration pathways. Our results are consistent with previous studies that suggest there may be two different populations utilizing the Chukchi Sea and central Aleutians in the fall and mix to some degree in the southern Bering Sea. Conversely, we found little difference between spring and fall recordings in the eastern Gulf of Alaska, suggesting some residency of whales in this region. This is likely due to fine scale similarities of calls among the inshore regions of British Columbia, while offshore areas are being utilized by whales traveling from various distant areas. This study shows how our novel approach to characterize recordings is an objective and informative way to standardize spatial and temporal comparisons of fin whale recordings.     

Phylogeography of the common goby, Pomatoschistus microps, with particular emphasis on the colonization of the Mediterranean and the North Sea

The phylogeographical patterns of a small marine fish, the common goby, Pomatoschistus microps, were assessed at 12 sites along the northeastern Atlantic coasts and the western Mediterranean Sea. A combination of two genetic markers was employed: cellulose acetate allozyme electrophoresis (CAGE) and sequence analysis of a 289 bp fragment of the mitochondrial locus cytochrome b. Both markers were congruent in revealing significant differences between samples (global FST = 0.247 for the allozymes and PhiST = 0.437 for the mitochondrial DNA data) and a pattern of isolation-by-distance. Phylogeographical analyses yielded a shallow branching structure with four groups. Three of those were confined to the Atlantic basin and showed a star-like pattern. The fourth group contained a central haplotype occurring at the edges of the species' distribution, accompanied by a few more rare variants, which were restricted to the Mediterranean Sea. A genetic break was observed around the British Isles, with distinct haplotypes dominating at either side of the English Channel. A significantly negative correlation between the degree of genetic diversity and latitude was recorded both for mitochondrial DNA (mtDNA) and allozymes in the Atlantic basin. Gene flow analysis suggested that recolonization of the North Sea and the coasts of western Scotland and Ireland may have taken place from a glacial refugium in the Southern Bight of the North Sea. These results are discussed in the perspective of possible postglacial migration routes of marine fish along the northeastern Atlantic coasts.     

Minimal similarity in songs suggests limited exchange between humpback whales (Megaptera novaeangliae) in the southern Indian Ocean

Comparing humpback whale song from different breeding assemblages can reveal similarities in song due to acoustically interacting males, and therefore indirectly test whether males from different breeding sites are mixing. Northern Hemisphere song comparisons illustrated that whales within ocean basins share similar songs and are subpopulations within a larger population, whereas whales in different ocean basins are isolated populations and therefore do not share songs. During the 2006 breeding season, recordings were collected in Madagascar and Western Australia, and were compared visually plus aurally. Both regions shared one theme, whereas each region had four and six private themes, respectively. This study had a substantially low number of shared themes. The co‐occurrence of one theme was interpreted as an indication of limited exchange between these breeding assemblages, and we speculate that limited song similarity is due to inter‐oceanic interactions. Male(s) from an Indian Ocean breeding group could be exposed to novel song when they geographically overlap, and acoustically interact, with males from a different ocean basin. Novel song could induce rapid temporal changes as new song content is incorporated, thereby minimizing song similarities between that breeding group and other Indian Ocean breeding groups that were not exposed to the novel song.     

Biogeography of the marine birds of a confined sea, the Mediterranean

Aim The Mediterranean sea is a winter productive oligotrophic basin where Atlantic water replaces water lost through evaporation, this influx being a major source of productivity and fertility. The long coastlines and the large number of islands cause high oceanographic heterogeneity. Moreover, during its geological history, it has dried out several times. So we describe the consequences of these particular features on species richness, distribution, and breeding ecology of marine birds. Location The Mediterranean sea (including the Black Sea and the Sea of Azov) communicates with the Atlantic Ocean only through a 14 km wide channel (Straits of Gibraltar), and since 1869, with the Red Sea through the Suez Canal. Methods The Mediterranean was subdivided into different areas, according to physical oceanographic entities and productivity, linked to numbers and distribution of both breeding and wintering marine birds (defined as species strongly dependent on marine resources, breeding only on islands and/or the coastline). Results The total marine bird biomass, and species diversity, are lower in the Mediterranean than in the near Atlantic. The eastern Mediterranean, with lowest primary productivity, contains fewer marine bird taxa than the more productive western part. Taxa which mainly occur in the western and southern parts of the Mediterranean migrate through the Straits of Gibraltar to winter in the southern Atlantic, while those inhabiting the northern and eastern parts are sedentary, as a result of differences in species composition. Northern coastal basin communities (i.e. the Tyrrhenian and the Balearic Seas), are composed of less pelagic, and earlier breeding species, that rear chicks during the productive season. These latter taxa are actually the most typical Mediterranean taxa, in terms of endemism. Main conclusions The Mediterranean marine bird community is not tropical, but rather, shows the highest affinity with the Atlantic temperate community. Its level of endemism is however high and comparable to other confined basins such as the Red Sea.     

Discerning between recurrent gene flow and recent divergence under a finite-site mutation model applied to North Atlantic and Mediterranean Sea fin whale (Balaenoptera physalus) populations

Genetic divergence among conspecific subpopulations can be due to either low recurrent gene flow or recent divergence and no gene flow. Here we present a modification of an earlier method developed by Nielsen and Wakeley (2001), which accommodates a finite-site mutation model, to assess which of the two models of divergence is most likely given the observed data. We apply the method to nucleotide sequence data collected from the variable part of the mitochondrial control region in fin whales (Balaenoptera physalus) from the Atlantic coast off Spain and the Mediterranean Sea. Our estimations strongly favor a model of recurrent gene flow over a model of recent divergence and zero gene flow. We estimated the migration rate at two females per generation. While the estimated rate is high by evolutionary standards, exchange rates of this order of magnitude is low from an ecological and conservation perspective and entirely consistent with the current paucity of fin whale sightings in the Strait of Gibraltar today. Intensive commercial shore-based whaling during the 1920s removed substantial numbers of fin whales in the Strait of Gibraltar and this local population has seemingly since failed to recover.     

Phylogeography of the common shrimp, Crangon crangon (L.) across its distribution range

The common or brown shrimp Crangon crangon (L.) is a highly abundant and important taxon, both ecologically and commercially, yet knowledge on its population structure and historical biogeography is limited. We studied population genetic structure across the distribution range of this species by sequencing a 388 bp fragment of the cytochrome-c-oxidase I gene for 140 individuals from 25 locations. Strong population structuring and high levels of genetic diversity were observed. Four main phylogroups were uncovered: northeastern Atlantic, western Mediterranean, Adriatic Sea and Black Sea. Gene flow of these shrimp across known oceanographical barriers (e.g., the Strait of Gibraltar and/or Oran-Almeria front, Sicilian Straits, and Turkish Straits) is severely restricted. The oldest and most variable populations currently inhabit the western Mediterranean. The observed absence of structure across the entire northeastern Atlantic shelf is proposed not to be due to gene flow, but to relatively recent colonization following the glacial cycles of the late Pleistocene. Black Sea shrimp are currently disconnected from Mediterranean populations, and colonization is inferred, on the basis of coalescent analysis, to have happened relatively recently, but possibly earlier than 7000 years ago. We postulate the hypothesis that C. crangon survived the last brackish-water (<7 per thousand) period inside the Black Sea and/or one of the adjacent inland seas. We conclude that (1) common shrimp populations from different basins are strongly differentiated, (2) gene flow across basins is probably very limited, and (3) the biogeographic history of the taxon is largely in accordance with the geographic history of its distribution range. This study provides further evidence that high population connectivity of marine species (e.g., by policy makers) should not be assumed.     

Annual Acoustic Presence of Fin Whale (Balaenoptera physalus) Offshore Eastern Sicily,Central Mediterranean Sea

In recent years, an increasing number of surveys have definitively confirmed the seasonal presence of fin whales (Balaenoptera physalus) in highly productive regions of the Mediterranean Sea. Despite this, very little is yet known about the routes that the species seasonally follows within the Mediterranean basin and, particularly, in the Ionian area. The present study assesses for the first time fin whale acoustic presence offshore Eastern Sicily (Ionian Sea), throughout the processing of about 10 months of continuous acoustic monitoring. The recording of fin whale vocalizations was made possible by the cabled deep-sea multidisciplinary observatory, “NEMO-SN1”, deployed 25 km off the Catania harbor at a depth of about 2,100 meters. NEMO-SN1 is an operational node of the European Multidisciplinary Seafloor and water-column Observatory (EMSO) Research Infrastructure. The observatory was equipped with a low-frequency hydrophone (bandwidth: 0.05 Hz–1 kHz, sampling rate: 2 kHz) which continuously acquired data from July 2012 to May 2013. About 7,200 hours of acoustic data were analyzed by means of spectrogram display. Calls with the typical structure and patterns associated to the Mediterranean fin whale population were identified and monitored in the area for the first time. Furthermore, a background noise analysis within the fin whale communication frequency band (17.9–22.5 Hz) was conducted to investigate possible detection-masking effects. The study confirms the hypothesis that fin whales are present in the Ionian Sea throughout all seasons, with peaks in call detection rate during spring and summer months. The analysis also demonstrates that calls were more frequently detected in low background noise conditions. Further analysis will be performed to understand whether observed levels of noise limit the acoustic detection of the fin whales vocalizations, or whether the animals vocalize less in the presence of high background noise.     

WEIGHTS AND ANATOMICAL MEASUREMENTS OF NORTHEASTERN ATLANTIC FIN (BALAENOPTERA PHYSALUS, LINNAEUS) AND SEI (B. BOREALIS, LESSON) WHALES

Piecemeal body weights of eleven fin and four sei whales and intact weights of three foetuses, obtained from Iceland, are compared with published weight data. The Icelandic fin are similar to other northern hemisphere animals but are significantly leaner than their Antarctic counterparts. The Icelandic sei appear heavier than the North Pacific sei whales. Their weights cannot be predicted from a North Pacific sei whale weight/length formula. Length, girth and blubber thickness measurements indicate changes in relative body dimensions in the early fin whale foetus compared with juveniles and adults; however, the midterm sei whale foetus is similar to the adult and juvenile sei whales. The blubber appears to form a major component even in the foetal body. The integration of a standard series of lengths, girths and blubber thicknesses in juveniles and adults can provide an estimate of the blubber component. Both girth and length are significant parameters in estimating body weight, a simple weight/length formula being found to be inadequate to allow for variability in body fatness. Evaluation of such a multiple parameter formula for calculating weight appears satisfactory for both fin and sei whales. Apparent weight/length differences between species and stocks may thus be partly due to variations in body fatness.     

Stable isotope analysis and fin whale subpopulation structure in the eastern North Atlantic

The North Atlantic fin whale was subject to heavy exploitation in the past and, despite partial recovery, it is still considered endangered. Recent research has questioned its currently accepted subpopulation structure and migratory movements, challenging management and conservation efforts. Here we contribute to this discussion by presenting results of stable isotope analysis of fin whale bones and krill samples collected from fin whale stomachs from two exploited areas, west Iceland and northwest Spain, and comparing these results with North Atlantic isoscapes. In krill, δ¹⁵N values were highly variable and no significant differences in δ¹⁵N and δ¹³C between areas emerged. δ¹⁵N and δ¹³C values in bone were higher than in krill, due to trophic enrichment, and were not significantly different between areas. Both krill and bone results were slightly inconsistent with the local isoscapes, maybe due to seasonal variations in local productivity and in krill diet and, in the case of bone, to its capability to integrate long‐term isotopic values, derived from food consumed in distant areas. Conversely, δ¹⁸O values, which reflect the basal signal of sea water, were consistent with isoscapes and significantly higher in whales from northwestern Spain, possibly indicating migration to breeding grounds located at lower latitudes.     

Historical colonization of the Mediterranean Sea by Atlantic fishes: do biological traits matter?

Since its opening 5.33 million years ago, the Gibraltar Strait has always contributed to the Mediterranean fauna and flora. Despite the increasing importance of the phenomenon, ecological determinants underlying colonization success of Atlantic fishes in the Mediterranean Sea have been poorly investigated. Here we reconstruct the recent historical colonization of the whole Mediterranean Sea by Atlantic fishes and we aim to determine where Atlantic fishes preferentially establish and whether some biological traits and ecological factors can be correlated to the colonization success (climate match, position in the water column, maximum body length, propagules, confamilial resistance, depth). A database on Atlantic fish species records from 1810 to 2006 was built and the colonization rate of each introduced species was estimated. Analysis of Variance, Chi squared test and logistic regression were used to investigate the relationships between ecological variables and colonization success. In addition, an index of asymmetry was used to analyse the relative colonization on the two sides of the Mediterranean Sea. Overall 48.33% of Atlantic species introduced in the Mediterranean Sea succeeded in colonizing eastwards. We found that habitat depth of Atlantic species is significantly related to their colonization success due to the obstacle of the shallow depth of the Gibraltar Strait (300 m). It also appears that despite the cyclonic general water circulation on the North Western basin, the northern side is more colonized than the southern one: 70.40% of the studied species colonize the northern side, while only 29.62% colonize the southern one. Two hypotheses may explain this trend: the bottom-up process that enhances the colonization success of Atlantic fishes along the Spanish coast of Alboran Sea owning to its high productivity and the intensiveness of the scientific explorations along the northern Mediterranean side. We conclude that crossing the Gibraltar Strait does not guarantee the colonization success and that species life-history and functional traits are poor predictors. Instead we suggest that environmental factors may determine favourable locations for invasive species installation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Handling editor: J. Cambray.     

High Source Levels and Small Active Space of High-Pitched Song in Bowhead Whales (Balaena mysticetus)

The low-frequency, powerful vocalizations of blue and fin whales may potentially be detected by conspecifics across entire ocean basins. In contrast, humpback and bowhead whales produce equally powerful, but more complex broadband vocalizations composed of higher frequencies that suffer from higher attenuation. Here we evaluate the active space of high frequency song notes of bowhead whales (Balaena mysticetus) in Western Greenland using measurements of song source levels and ambient noise. Four independent, GPS-synchronized hydrophones were deployed through holes in the ice to localize vocalizing bowhead whales, estimate source levels and measure ambient noise. The song had a mean apparent source level of 185±2 dB rms re 1 µPa @ 1 m and a high mean centroid frequency of 444±48 Hz. Using measured ambient noise levels in the area and Arctic sound spreading models, the estimated active space of these song notes is between 40 and 130 km, an order of magnitude smaller than the estimated active space of low frequency blue and fin whale songs produced at similar source levels and for similar noise conditions. We propose that bowhead whales spatially compensate for their smaller communication range through mating aggregations that co-evolved with broadband song to form a complex and dynamic acoustically mediated sexual display.     

Conservation genetics of the short-beaked common dolphin (<Emphasis Type="Italic">Delphinus delphis</Emphasis>) in the Mediterranean Sea and in the eastern North Atlantic Ocean

Mediterranean Sea common dolphins have recently been listed as ‘endangered’ in the IUCN Red list, due to their reported decline since the middle of the 20th century. However, little is know about the number or distribution of populations in this region. We analysed 118 samples from the Black Sea, Mediterranean Sea and eastern North Atlantic at nine microsatellite nuclear loci and for 428 bps of the mtDNA control region. We found small but significant population differentiation across the basin between the eastern and the western Mediterranean populations at both nuclear and mtDNA markers (microsatellite F _ST = 0.052, mtDNA F _ST = 0.107, P values ≤ 0.001). This matched the differential distribution and habitat use patterns exhibited by this species in the eastern and the western parts of the Mediterranean Sea. The assignment test of a small number of samples from the central Mediterranean could not exclude further population structure in the central area of the basin. No significant genetic differentiation at either marker was observed among the eastern north Atlantic populations, though the Alboran population (inhabiting the Mediterranean waters immediately adjacent the Atlantic ocean) showed significant mtDNA genetic differentiation compared to the Atlantic populations. Directional estimates of gene flow suggested movement of females out of the Mediterranean, which may be relevant to the population decline. Phylogenetic analysis suggested that the observed population structure evolved recently.     

NORTH PACIFIC HUMPBACK WHALE SONGS: A COMPARISON OF SOUTHEAST ALASKAN FEEDING GROUND SONGS WITH HAWAIIAN WINTERING GROUND SONGS

Humpback whales sing long, complex songs on their wintering grounds. On 25 August 1979 and 3 September 1981, we made recordings of humpback whale songs in southeastern Alaska, showing that humpback whales also sing on the summer feeding grounds. Both these Alaskan samples are songs in that they are repeating cyclical sound patterns and follow the known structure for humpback whale song. The Alaskan songs contain all the same material sung in the same order as that heard off Mexico and Hawaii in the surrounding wintering seasons. However, song, theme and some phrase durations are abbreviated in the Alaskan songs. The recording of these two songs represents the full sample of song recorded from 155 days over five years of attempting to record humpback whale song in Alaskan waters.