Sally Mizroch

1. We summarize fin whale Balaenoptera physalus catch statistics, sighting data, mark recoveries and acoustics data. The annual cycle of most populations of fin whales had been thought to entail regular migrations between high-latitude summer feeding grounds and lower-latitude winter grounds. Here we present evidence of more complex and varied movement patterns. 2. During summer, fin whales range from the Chukchi Sea south to 35°N on the Sanriku coast of Honshu, to the Subarctic Boundary (ca. 42°N) in the western and central Pacific, and to 32°N off the coast of California. Catches show concentrations in seven areas which we refer to as 'grounds', representing productive feeding areas. 3. During winter months, whales have been documented over a wide area from 60°N south to 23°N. Coastal whalers took them regularly in all winter months around Korea and Japan and they have been seen regularly in winter off southern California and northern Baja California. There are also numerous fin whale sightings and acoustic detections north of 40°N during winter months. Calves are born during the winter, but there is little evidence for distinct calving areas. 4. Whales implanted with Discovery-type marks were killed in whaling operations, and location data from 198 marked whales demonstrate local site fidelity, consistent movements within and between the main summer grounds and long migrations from low-latitude winter grounds to high-latitude summer grounds. 5. The distributional data agree with immunogenetic and marking findings which suggest that the migratory population segregates into at least two demes with separate winter mating grounds: a western ground off the coast of Asia and an eastern one off the American coast. Members of the two demes probably mingle in the Bering Sea/Aleutian Islands area. 6. Prior research had suggested that there were at least two non-migratory stocks of fin whale: one in the East China Sea and another in the Gulf of California. There is equivocal evidence for the existence of additional non-migratory groups in the Sanriku-Hokkaido area off Japan and possibly the northern Sea of Japan, but this is based on small sample sizes.

This dataset contains visual observations of sei and other whale abundance from research vessel Yushin-Maru No.3 in the North Pacific Ocean. It provides information for the proposed future in-depth assessment of sei and other whales in terms of both abundance and stock structure. This MSR RATS cruise U2011-005. These data are part of the World Data Services for Oceanography. Cruise report is in PDF.

This dataset contains visual sightings of blue, sei, fin whales from the research vessel Yushin-Maru No.3 in the North Pacific Ocean. It provides information for the proposed future in-depth assessment of sei and other whales in terms of both abundance and stock structure. This is MSR RATS cruise U2012-001. These data are part of the World Data Services for Oceanography. Cruise report is in PDF.

The Gulf of California, Mexico is home to many cetacean species, including a presumed resident population of fin whales, Balaenoptera physalus. Past studies reported very low levels of genetic diversity among Gulf of California fin whales and a significant level of genetic differentiation from con-specifics in the eastern North Pacific. The aim of the present study was to assess the degree and timing of the isolation of Gulf of California fin whales in a population genetic analysis of 18 nuclear microsatellite genotypes from 402 samples and 565 mitochondrial control region DNA sequences (including mitochondrial sequences retrieved from NCBI). The analyses revealed that the Gulf of California fin whale population was founded ~2.3 thousand years ago and has since remained at a low effective population size (~360) and isolated from the eastern North Pacific (Nem between 0.89–1.4). The low effective population size and high degree of isolation implied that Gulf of California fin whales ...

sperm, minke and bowhead whales) was in decline in the Bering Sea in the 1960s and early 1970s; and (3) pinniped declines in the 1970s and 1980s were sequential. We concluded that the available data are not consistent with the first two assump-

Previous genetic analyses have demonstrated that the fin whales in the Sea of Cortez likely are genetically (and presumably demographically) isolated from North Pacific fin whales. Consequently the Sea of Cortez fin whale population is likely more vulnerable to anthropogenic effects and habitat changes. Here we extend previous work by genetic analyses of microsatellite and mtDNA nucleotide sequences in 375 and 24 fin whale samples from the Sea of Cortez and North Pacific, respectively. We will estimate long- and short-term effective population sizes in these two populations and compare the estimates with data from the much larger North Atlantic fin whale population(s). The objective of the analysis is to assess how vulnerable the Sea of Cortez fin whale population is to random genetic effects, such as loss of adaptive potential and inbreeding.

NOTE – NMFS is in the process of reviewing humpback whale stock structure under the Marine Mammal Protection Act (MMPA) in light of the 14 Distinct Population Segments established under the Endangered Species Act (ESA) (81 FR 62259, 8 September 2016). A complete revision of the humpback whale stock assessments will be postponed until this review is complete. In the interim, new information on humpback whale mortality and serious injury is provided within this report.

NOTE – December 2015: In areas outside of Alaska, studies of harbor porpoise distribution have indicated that stock structure is likely more fine-scaled than is reflected in the Alaska Stock Assessment Reports. No data are available to define stock structure for harbor porpoise on a finer scale in Alaska. However, based on comparisons with other regions, it is likely that several regional and sub-regional populations exist. Should new information on harbor porpoise stocks become available, the harbor porpoise Stock Assessment Reports will be updated.

Cook Inlet beluga whales, Delphinapterus leucas, are currently listed as ‘Endangered’ under the U.S. Endangered Species Act (ESA). The National Marine Fisheries Service (NMFS) began monitoring this population during the 1990s after it was added to the ESA Candidate Species list in 1988. Monitoring efforts included aerial surveys, and in 1995, the first attempts to capture and satellite-tag whales. Working with Canadian scientists and Alaska Native subsistence hunters in 1995 and 1997, tagging methods were adapted to conditions in Cook Inlet (muddy water, extreme tides, and extensive mudflats), culminating in successful capture and tracking of a whale during the summer of 1999. This was followed by three more years of capture and tagging studies during late summer. Tags were attached to 18 whales between 1999 and 2002. We do not have detailed accounts of these later tagging seasons (e.g., similar to the Appendix chronicling events from the 1997 and 1999 seasons in Ferrero et al. (200...

... C. Shane Reese, James A. Calvin, John C. George, and Raymond J. Tarpley ... James Calvin is Professor of Statistics at Texas A&M University, College Station. John George is a wildlife biologist at the North Slope Borough, Department of Wildlife Management, Barrow, AK. ...

The advent of massive parallel sequencing technologies has resulted in an increase of studies based upon complete mitochondrial genome DNA sequences that revisit the taxonomic status within and among species. Spatially distinct monophyly in mitogenomic genealogies, i.e., the sharing of a recent common ancestor among con-specific samples collected in the same region has been viewed as evidence for subspecies. Several recent studies in cetaceans have employed this criterion to suggest subsequent intraspecific taxonomic revisions. We reason that employing intra-specific, spatially distinct monophyly at non-recombining, clonally inherited genomes is an unsatisfactory criterion for defining subspecies based upon theoretical (genetic drift) and practical (sampling effort) arguments. This point is illustrated by a re-analysis of a global mitogenomic assessment of fin whales, Balaenoptera physalus spp., published by Archer et al. (2013) which proposed to further subdivide the Northern Hemis...

Springer et al. (2003; Proc Natl Acad Sci USA 100:12223–12228) hypothesized that populations of seals, sea lions and sea otters in the northern North Pacific Ocean and Bering Sea declined
because of increased predation by killer whales, in what they termed a ‘sequential megafaunal collapse’.  They hypothesized that the killer whales had been dependent on large whales for food, and that their increased predation on the smaller marine mammals was directly due to the depletion of great whale populations as a result of post-World War II industrial whaling. The maps presented by Springer et al. (2003) masked the development and precipitous decline of post-World War II industrial whaling. Our analysis shows that north of 50° N, whaling developed slowly from 1948 to 1951, expanded steadily from 1952 to 1962, and increased very sharply from 1963 to 1967. By 1968, there was near total drop-off in catches north of 50°N as the whaling fleets moved south. Because of the extraordinary whale biomass removals in the mid-1960s, any whaling-related prey shifting should have started by 1968, not the mid-1970s as they suggested. We also present data that refute their assumption that North Pacific killer whales depended on large whales as prey either prior to or concurrent with the whaling era. During the years of the development and pulse of whaling (i.e. prior to 1968), less than 3% of the mammal-eating killer whales were observed to have large whale remains in their stomachs. Killer whales attack healthy, adult large whales only rarely, and such attacks are usually unsuccessful. Neither minke nor gray whales were depleted by post-World War II industrial whaling, and they have always been available as prey for North Pacific killer whales.

We investigated the distribution and movements of sperm whales (Physeter macrocephalus) in the North Pacific by analyzing whaling data and movement data of whales marked with Discovery marks. Prior studies suggested that there were discrete “stocks” of sperm whales, assuming that the intervals between historical areas of concentration indicated subpopulation boundaries. Our analyses clearly refute this assumption: whaling and marking data suggest no obvious divisions between separate demes or stocks within the North Pacific. Sperm whales appear to be nomadic and show widespread movements between areas of concentration, with documented movements of over 5,000 km, time spans
between marking and recovery over 20 yr, and ranges that cover many thousand km2. Males appear to range more widely than females. Sperm whales likely travel in response to geographical and temporal variations in the abundance of
medium- and large-sized pelagic squids, their primary prey. Our analyses demonstrate that males and females concentrated seasonally in the Subtropical Frontal Zone (ca. 28ºN–34ºN) and the Subarctic Frontal Zone (ca. 40ºN–43ºN),
and males also concentrated seasonally near the Aleutian Islands and along the Bering Sea shelf edge. It appears that the sperm whales targeted by the pelagic whalers range widely across this ocean basin.