Contrasting abundance and residency patterns of two sympatric populations of transient killer whales (Orcinus orca) in the northern Gulf of Alaska

Two sympatric populations of “transient” (mammal-eating) killer whales were photo-identified over 27 years (1984–2010) in Prince William Sound and Kenai Fjords, coastal waters of the northern Gulf of Alaska (GOA). A total of 88 individuals were identified during 203 encounters with “AT1” transients (22 individuals) and 91 encounters with “GOA” transients (66 individuals). The median number of individuals identified annually was similar for both populations (AT1=7; GOA=8), but mark-recapture estimates showed the AT1 whales to have much higher fidelity to the study area, whereas the GOA whales had a higher exchange of individuals. Apparent survival estimates were generally high for both populations, but there was a significant reduction in the survival of AT1 transients after the Exxon Valdez oil spill in 1989, with an abrupt decline in estimated abundance from a high of 22 in 1989 to a low of seven whales at the end of 2010. There was no detectable decline in GOA population abundance or survival over the same period, but abundance ranged from just 6 to 18 whales annually. Resighting data from adjacent coastal waters and movement tracks from satellite tags further indicated that the GOA whales are part of a larger population with a more extensive range, whereas AT1 whales are resident to the study area

Seasonal Characteristics of Humpback Whales {Megaptera novaeangliae) in Southeastern Alaska

Humpback whales were studied in southeastern Alaska to assess seasonal distribution and numbers, migration patterns, length of stay, female reproductive histories, and calf survival. A mean annual estimate and 95% confidence interval of whales present in the study areas was 404 ± 54 individuals. The longest length of stay was nearly 7 months, and the shortest transit to the Hawaiian mating and calving grounds was 39 days. Generally, birth intervals did not vary from one calf every two or three years; individual variation ranged from one to five years. There were few resightings of whales first seen as calves. The recovery of North Pacific humpback whales will only occur through an increase in the survival of calves to become sexually mature and reproducing adults.The authors are grateful for the assistance and patience of many people who contributed to this study. These people include J. Straley, F. Fay, A. Perry, T. Quinn II, S. Mizroch, K. Metcalf, J. Greenough, C. Greenough, C. Johnstone, D. Matkin, and L. Quakenbush. These data were collected under National Marine Fisheries Service scientific research permits issued to Glacier Bay National Park (#600) and J. Straley (#571).Ye

Summary of Reported Whale-Vessel Collisions in Alaskan Waters

Here we summarize 108 reported whale-vessel collisions in Alaska from 1978–2011, of which 25 are known to have resulted in the whale's death. We found 89 definite and 19 possible/probable strikes based on standard criteria we created for this study. Most strikes involved humpback whales (86%) with six other species documented. Small vessel strikes were most common (<15 m, 60%), but medium (15–79 m, 27%) and large (≥80 m, 13%) vessels also struck whales. Among the 25 mortalities, vessel length was known in seven cases (190–294 m) and vessel speed was known in three cases (12–19 kn). In 36 cases, human injury or property damage resulted from the collision, and at least 15 people were thrown into the water. In 15 cases humpback whales struck anchored or drifting vessels, suggesting the whales did not detect the vessels. Documenting collisions in Alaska will remain challenging due to remoteness and resource limitations. For a better understanding of the factors contributing to lethal collisions, we recommend (1) systematic documentation of collisions, including vessel size and speed; (2) greater efforts to necropsy stranded whales; (3) using experienced teams focused on determining cause of death; (4) using standard criteria for validating collision reports, such as those presented in this paper.The authors gratefully acknowledge the many organizations and individuals who have reported and collected data on whale-vessel collisions over the years including members of the Alaska Marine Mammal Stranding Network; the US Coast Guard; NOAA Enforcement; the Alaska Department of Fish & Game; the Alaska State Troopers; tour operators; vessel captains, pilots, and crew; harbormasters; fishermen; recreational boaters; Charles Jurasz; and C. Scott Baker. They thank John Sease, Linda Shaw, and Kaja Brix for developing the Alaska Marine Mammal Stranding Network with limited resources; Mary Sternfeld, who shepherded the NOAA Alaska Region Stranding Database through its infancy; Doug DeMaster for initiating the first paper on this topic for the IWC in 2007 and for providing valuable comments on this paper. Special credit goes to Dr. Frances Gulland from The Marine Mammal Center for leading necropsies in Alaska, training local responders in ship strike necropsy methods, and contributing her expertise to this paper. They extend sincere thanks to the Alaskan marine mammal veterinarians (Dr. Kathy Burek, Dr. Rachel Dziuba, Dr. Carrie Goertz, Dr. Kate Savage, and Dr. Pam Tuomi) and volunteers who have conducted and participated in whale necropsies. They are indebted to Jen Cedarleaf (UAS) for her expert fluke matching skills which allowed them to identify several of the dead humpback whales in this study. They thank John Moran (NOAA), Fred Sharpe (Alaska Whale Foundation), and Erin Falcone (Cascadia Research Collective) for sharing photos of live whales with collision injuries. They are grateful to David Mattila (IWC), Ed Lyman (NOAA), and Jerry Dzugan (Alaska Marine Safety Education Association) for contributing to and supporting this study. They thank Whitney Rapp and Greg Ambrose for their help developing the hotspot map. They thank two anonymous reviewers for their valuable comments on this paper. Necropsies on endangered whales were conducted under National Marine Fisheries Service (NMFS) permits 932-1489 and 932-1905.Ye

Humpback whales feed on hatchery-released juvenile salmon

Thank you to staff and managers at NSRAA, Armstrong Keta Inc. and NOAA for collecting data daily during their release seasons. Bart Watson collaborated in study design. Thank you to Elena McCauley, R. Katy Pendell and Margaret Schoenfeld for data entry.Humpback whales are remarkable for the behavioural plasticity of their feeding tactics and the diversity of their diets. Within the last decade at hatchery release sites in Southeast Alaska, humpback whales have begun exploiting juvenile salmon, a previously undocumented prey. The anthropogenic source of these salmon and their important contribution to local fisheries makes the emergence of humpback whale predation a concern for the Southeast Alaska economy. Here, we describe the frequency of observing humpback whales, examine the role of temporal and spatial variables affecting the probability of sighting humpback whales and describe prey capture behaviours at five hatchery release sites. We coordinated twice daily 15 min observations during the spring release seasons 2010–2015. Using logistic regression, we determined that the probability of occurrence of humpback whales increased after releases began and decreased after releases concluded. The probability of whale occurrence varied among release sites but did not increase significantly over the 6 year study period. Whales were reported to be feeding on juvenile chum, Chinook and coho salmon, with photographic and video records of whales feeding on coho salmon. The ability to adapt to new prey sources may be key to sustaining their population in a changing ocean.Ye

Ecosystem response persists after a prolonged marine heat wave

Some of the longest and most comprehensive marine ecosystem monitoring programs were established in the Gulf of Alaska following the environmental disaster of the Exxon Valdez oil spill over 30 years ago. These monitoring programs have been successful in assessing recovery from oil spill impacts, and their continuation decades later has now provided an unparalleled assessment of ecosystem responses to another newly emerging global threat, marine heatwaves. The 2014–2016 northeast Pacific marine heatwave (PMH) in the Gulf of Alaska was the longest lasting heatwave globally over the past decade, with some cooling, but also continued warm conditions through 2019. Our analysis of 187 time series from primary production to commercial fisheries and nearshore intertidal to offshore oceanic domains demonstrate abrupt changes across trophic levels, with many responses persisting up to at least 5 years after the onset of the heatwave. Furthermore, our suite of metrics showed novel community-level groupings relative to at least a decade prior to the heatwave. Given anticipated increases in marine heatwaves under current climate projections, it remains uncertain when or if the Gulf of Alaska ecosystem will return to a pre-PMH state."This project was made possible by the Gulf Watch Alaska (GWA) long-term ecosystem monitoring program with financial support by the Exxon Valdez Oil Spill Trustee Council (EVOSTC)."Ye

Local recruitment of humpback whales in Glacier Bay and Icy Strait, Alaska, over 30 years

We provide new information on the scale at which fidelity and recruitment underlie observed increases in humpback whale Megaptera novaeangliae populations.We provide new information on the scale at which fidelity and recruitment underlie observed increases in humpback whale Megaptera novaeangliae populations. We used photoidentification records and DNA profiles from whales in Glacier Bay and Icy Strait (GBIS), southeastern Alaska (SEAK) to investigate 3 sources of population increase over 33 yr (1973−2005): local GBIS recruitment, recruitment from elsewhere in SEAK, and immigration from outside SEAK. We defined 2 temporal strata for these longitudinal records: ‘founder’ individuals identified from 1973 to 1985 (n = 74; n = 46 with DNA profiles) and ‘contemporary’ individuals identified from 2004 to 2005 (n = 171; n = 118 with DNA profiles). To distinguish between local recruitment and recruitment from elsewhere in SEAK, we estimated the proportion of the contemporary stratum that was either a returning founder or descended from a founder female. After excluding 42 contemporary whales without a known mother or genotype to infer maternity, 73.6% of the contemporary stratum was confirmed or inferred through parentage analysis to be either a returning founder or a descendant of a founder mother. Of the 25 females with genotypes in the founder stratum, 24 (96%) were either represented in the contemporary stratum, had at least 1 descendant in the contemporary stratum, or both. We found no significant differences in microsatellite allele or mtDNA frequencies between the strata, suggesting little or no immigration from other feeding grounds. Our results highlight the importance of local habitat protection for a recovering species with culturally inherited migratory destinations.Ye

mtDNA heteroplasmy gives rise to a new maternal lineage in North Pacific humpback whales

Heteroplasmy in the mitochondrial genome offers a rare opportunity to track the evolution of a newly arising maternal lineage in populations of non-model species. Here, we identified a previously unreported mitochondrial DNA haplotype while assembling an integrated database of DNA profiles and photo-identification records from humpback whales in southeastern Alaska (SEAK). The haplotype, referred to as A8, was shared by only two individuals, a mature female with her female calf, and differed by only a single base pair from a common haplotype in the North Pacific, referred to as A-. To investigate the origins of the A8 haplotype, we reviewed n = 1,089 electropherograms (including replicate samples) of n = 710 individuals with A- haplotypes from an existing collection. From this review, we found 20 individuals with clear evidence of heteroplasmy for A-/A8 (parental/derived) haplotypes. Of these, 15 were encountered in SEAK, four were encountered on the Hawaiian breeding ground (the primary migratory destination for whales in SEAK) and one was encountered in the northern Gulf of Alaska. We used genotype exclusion and likelihood to identify one of the heteroplasmic females as the likely mother of the A8 cow and grandmother of the A8 calf, establishing the inheritance and germ-line fixation of the new haplotype from the parental heteroplasmy. The mutation leading to this heteroplasmy and the fixation of the A8 haplotype provide an opportunity to document the population dynamics and regional fidelity of a newly arising maternal lineage in a population recovering from exploitation.Funding Support for this work was provided by a cooperative agreement between Oregon State University and the National Park Service (Pacific West Region Cooperative Ecosystems Study Unit Task Agreement #P12AC15004). Additional funding was provided by the Mamie Markham Research Award, Joan Crebbin Memorial Fellowship, Lylian Brucefield Reynolds Scholarship, Thomas G. Scott Grant Scholarship and the Hatfield Marine Science Center Student Organization Travel Grant. Acknowledgements We thank the SPLASH Steering Committee for access to haplotype information and sighting records. A special thanks to Charles Jurasz for his insight and foresight in documenting individual whales in southeastern Alaska. All research was conducted under appropriate permits issued by the US National Marine Fisheries Service, in accordance with the US Marine Mammal Protection Act and the US Endangered Species Act, including no. 14122 issued to J.M.S., nos. 945-1499-02 and 473-1700- 00 issued to the Glacier Bay National Park, and no. 675 issued to C.S.B.Ye

Using line acceleration to measure false killer whale (Pseudorca crassidens) click and whistle source levels during pelagic longline depredation

False killer whales (Pseudorca crassidens) depredate pelagic longlines in offshore Hawaiian waters. On January 28, 2015 a depredation event was recorded 14m from an integrated GoPro camera, hydrophone, and accelerometer, revealing that false killer whales depredate bait and generate clicks and whistles under good visibility conditions. The act of plucking bait off a hook generated a distinctive 15 Hz line vibration. Two similar line vibrations detected at earlier times permitted the animal’s range and thus signal source levels to be estimated over a 25-min window. Peak power spectral density source levels for whistles (4–8 kHz) were estimated to be between 115 and 130 dB re 1 lPa2/Hz @ 1 m. Echolocation click source levels over 17–32 kHz bandwidth reached 205 dB re 1lPa @ 1 m pk-pk, or 190 dB re 1lPa @ 1 m (root-meansquare). Predicted detection ranges of the most intense whistles are 10 to 25 km at respective sea states of 4 and 1, with click detection ranges being 5 times smaller than whistles. These detection range analyses provide insight into how passive acoustic monitoring might be used to both quantify and avoid depredation encounters.The authors are indebted to Captain Jerry Ray and the rest of the F/V Katy Mary crew for permitting the camera gear to be deployed during their longline fishing trip. Robert Glatts designed the custom GoPro circuit board, and Will Cerf assisted with video footage analysis. This research was sponsored by Derek Orner under the Bycatch Reduction Engineering Program (BREP) at the National Oceanic and Atmospheric Administration (NOAA).Ye

Seasonal presence and potential influence of humpback whales on wintering Pacific herring populations in the Gulf of Alaska

This study addressed the lack of recovery of Pacific herring (Clupea pallasii) in Prince William Sound, Alaska, in relation to humpback whale (Megaptera novaeangliae) predation.This study addressed the lack of recovery of Pacific herring (Clupea pallasii) in Prince William Sound, Alaska, in relation to humpback whale (Megaptera novaeangliae) predation. As humpback whales rebound from commercial whaling, their ability to influence their prey through top-down forcing increases. We compared the potential influence of foraging humpback whales on three herring populations in the coastal Gulf of Alaska: Prince William Sound, Lynn Canal, and Sitka Sound (133–147°W; 57–61°N) from 2007 to 2009. Information on whale distribution, abundance, diet and the availability of herring as potential prey were used to correlate populations of overwintering herring and humpback whales. In Prince William Sound, the presence of whales coincided with the peak of herring abundance, allowing whales to maximize the consumption of overwintering herring prior to their southern migration. In Lynn Canal and Sitka Sound peak attendance of whales occurred earlier, in the fall, before the herring had completely moved into the areas, hence, there was less opportunity for predation to influence herring populations. North Pacific humpback whales in the Gulf of Alaska may be experiencing nutritional stress from reaching or exceeding carrying capacity, or oceanic conditions may have changed sufficiently to alter the prey base. Intraspecific competition for food may make it harder for humpback whales to meet their annual energetic needs. To meet their energetic demands whales may need to lengthen their time feeding in the northern latitudes or by skipping the annual migration altogether. If humpback whales extended their time feeding in Alaskan waters during the winter months, the result would likely be an increase in herring predationAll humpback whale photographic data collected was authorized under scientific research permits 473-1700-01 and 782-1719 issued to Janice M. Straley and the National Marine Mammal Lab, respectively, from NOAA, Office of Protected Resources, WA, DC. In addition, this research was conducted with the authorization 08-07 of the Institutional Animal Care and Use Committee (IACUC), University of Alaska Fairbanks. Special thanks to D. Janka, and his knowledge of Prince William Sound and all the crew that joined us on our surveys. Also, thanks to Jennifer Cedarleaf, Ellen Chenoweth, Keith Cox, Suzie Teerlink, Fletcher Sewall, and others that assisted on surveys in Sitka Sound and Lynn Canal. Thanks to the Captains and crews of the NOAA Vessel John N Cobb, M/V Auklet, M/V Steller, and M/V Alaskan Adventurer, Heather Riley, Neil Dawson, Jennifer Cedarleaf, Ellen Chenoweth, Kate McLaughlin, Andy McLaughlin, Craig Matkin, Olga von Ziegesar, Fletcher Sewall, John Hudson, Keith Cox, Prince William Sound Science Center and Alaska Department of Fish and Game, Cordova. Reference to trade names does not imply endorsement by the National Marine Fisheries Service, NOAA. The findings and conclusions of this paper are those of the authors and do not necessarily represent the views of the National Marine Fisheries Service. The Exxon Valdez Oil Spill Trustee Council (award NA17NMF4720027) supported the research described in this paper. However, the findings and conclusions presented by the author(s) are their own and do not necessarily reflect the views or position the Trustee Council. The authors disclose there was no actual or potential conflict of interest including any financial, personal, or other relationships with other people or organizations within three years of beginning the submitted work that could inappropriately influence, or be perceived to influence, their work.Ye