Sarah Mesnick

NOAA Fisheries Southwest Fisheries Science Center
Phone:  858-546-7148
Fax:  858-546-7003

Dr. Mesnick's research focuses on social evolution in the ocean and on the role of social behavior in explaining patterns of species diversity. Since receiving her Ph.D. in ecology and evolutionary biology at the University of Arizona (1996) her interests have shifted from marine fishes to mammals. The main goal of her research in recent years is to provide a social framework within which to investigate stock identity, population trends, and fishery interactions in cetaceans. She uses a variety of tools (genetic, acoustic, behavioral, comparative and phylogenetic) and works in collaboration on a number of different management issues. The unifying theme of these projects is to bring a social perspective to our understanding of the dynamics of marine mammal populations to use this knowledge to manage marine mammal populations more effectively. Her research interests include social and sexual ecology, social signals, social and population structure, social bonds and social disruption, and sexual selection.

Current projects:
    * Investigating population and social structure of sperm whales using molecular genetic techniques with Barbara Taylor (SWFSC) and Hal Whitehead (Dalhousie University)
    * A comparative study of the behavior and sexual ecology of eastern tropical Pacific dolphins (with Bill Perrin, SWFSC)
    * Using acoustics to characterize blue whale populations worldwide (with John Hildebrand, SIO, and Mark MacDonald, Whaleacoustics)
    * A survey of sexual dimorphism, sperm competition and mating systems in the odontocete cetaceans (with Anne Allen, SWFSC and Alan Dixson and Matt Anderson, San Diego Zoo)
    * Investigating sperm whale depredation on the longline fishery for blackcod in southeast Alaska (with Jan Straley, University of Alaska)
    * A molecular genetic study of the California sea lions complex (with Yolanda Schramm, Universidad Autónoma de Baja California)


Project Title: Social and population structure of North Pacific sperm whales
Collaborators: Barbara Taylor (NOAA Fisheries) and Hal Whitehead (Dalhousie University)
Dates: 1997 - present
Funding Agency: Protected Resources, NOAA Fisheries
When populations are comprised of groups that contain related individuals, traditional methods of estimating population structure are biased; our work provides a new look at sperm whale stock identity in the North Pacific by taking into account the social structure of the species. This is a molecular project in which we use both nuclear and mitochondrial markers to determine population and social structure. To date, we have examined samples from hundreds of individuals across the North Pacific within dozens of social groups. We use these data to re-examine stock designations for management and to determine patterns of relatedness within groups of sperm whales encountered at sea. I also work in collaboration on a number of other management issues involving sperm whales. I am involved in a collaborative effort with Phillip Morin (SWFSC) and Terry Gasterlaand (SIO) to use sperm whales as a model system with which to develop single nucleotide polymorphisms (SNP) markers for use in conservation genetics. I am looking forward to putting together a project with a team of international researchers (Dan Englehaut, Kenneth Richard, Mary Dillon, Jo Bond and Hal Whitehead), to examine worldwide population structure in sperm whales. I am also interested in the use of acoustic signals to discriminate stock boundaries and to compare analyses using acoustic data with those using molecular data (collaborations with Hal Whitehead, Dalhousie University, and with John Hildebrand, SIO). We are engaged along with others in the investigation of the unusually low mitochondrial diversity of sperm whales and we are investigating the possibility that their deep diving behavior may be a factor in the evolution of this portion of the genome (with Andy Dizon, SWFSC). Lastly, I am collaborating in investigations of killer whale behavior, ecology and evolution and how the risk of predation by mammal eating killer whales influences the behavior and ecology of other cetacean species (with Bob Pitman, SWFSC).
Publications: a series of NOAA Administrative and International Whaling Commission Reports; Mesnick et al., 2003, Mesnick 2001, Pitman et al., 2001, Mesnick et al., 1999; Mesnick et al, in prep; Taylor and Mesnick, in prep.

Project Title: Sperm Whale Depredation on the Longline Fishery for Blackcod in Southeast Alaska
Collaborators: Jan Straley (University of Alaska)
Dates: 2003 - 2004
Funding Agency: North Pacific Research Council (184.5K)
Overview: Sperm whales are depredating (predating) on the longlines which fish for blackcod in the Gulf of Alaska. My involvement in this project is to merge information gleaned from genetic markers to identify the gender, number of individuals and population identity of the animals involved. This information will be used to estimate the extent of the problem and to design measures for mitigation.
Publications: Workshop report (Mitchell et al., 2002).

Project Title: Phylogeography of California Sea lions
Collaborators: Yolanda Schramm Urrutia (Universidad Aut&oacutenoma de Baja California, UABC)
Dates: 2000 - present
Funding Agency: NOAA Fisheries
Overview: A molecular study of Yolanda Schramm Urrutia, a recent PhD student, to define population structure in the California sea lions. Results recognize four populations, including an isolated population in the upper Gulf of California. This project includes every major rookery in the California sea lion as well as several for the Galapagos sea lion. We are particularly interested in determining the population boundaries along the Pacific coast of California and Baja California because U.S. marine mammal management is based on the political boundary at the US/Mexico border. Future studies will add nuclear markers and a closer look at the Galapagos sea lion.
Publication: Schramm Urrutia et al., in prep.

Project Title: Biogeographic Characterization of Blue Whale Song Worldwide
Collaborators: Mark McDonald and John Hildebrand (Scripps Institution of Oceanography)
Dates: 2002 - present
Funding Agency: NOAA Fisheries (for S.M.), Pacific Life Foundation (10K)
Overview: I use the approach that acoustic signals are good indicators of population identity because they are social signals used by the animals themselves to maintain associations and mediate social interactions. To test this hypothesis, we are comparing biogeographic patterns of song type in blue whales with results from genetic analyses to obtain independent estimates of stock identity and boundaries. We are looking forward to expanding this approach to study sperm whale acoustic and genetic structure on a world-wide basis.
Publication: McDonald, Mesnick and Hildebrand, submitted.

Project Title: Sexual Ecology of Eastern Tropical Pacific Dolphins
Collaborators: Bill Perrin
Dates: 2001 - present
Funding Agency: NOAA Fisheries
Overview: We are interested in documenting the variation in the reproductive ecology of eastern tropical Pacific (ETP) dolphins, gaining a better understanding of the links between this variation and the ecological context in which these animals reside, and interpreting the results in a management context. We use physical characteristics as an indicator of the strength of sexual selection: testes size and patterns of sexual dimorphism. In a recent publication (Perrin and Mesnick 2003), we apply sperm competition theory to interpret the dramatic difference between the testes sizes and appendage morphology of the eastern and whitebelly morphs of spinner dolphins. The results suggest that the eastern spinner has a much more structured, strongly polygynous, mating system than the whitebelly spinner. We suggest management recommendations for avoiding perturbation (by tuna-purse fishing) during critical periods (e.g., mating and lactation windows).
Publication: Perrin and Mesnick 2003

Project Title: Mating Strategies and Mating Systems of the Odontocete Cetaceans
Collaborators: Kathryn Ralls (Smithsonian Institution), Alan Dixson and Matt Anderson (Center for Reproduction of Endangered Species at the San Diego Zoo), and Anne Allen (NOAA Fisheries)
Dates: 2000 - present
Funding Agency: NOAA Fisheries (for S.M.)
Overview: This research comprises a survey of the reproductive strategies of male and female marine mammals and includes a comparative study of relative testis size and sexual dimorphism across odontocete cetaceans (the toothed whales). Results enable us to make predictions about the mating systems of many species which were previously unknown and to test these predictions against models from primates. Completed are three review papers on marine mammal mating systems. On-going is a comparative study using phylogenetic methodologies (independent contrasts).
Publications: Mesnick and Ralls 2002; Ralls and Mesnick 2002; Boness et al. 2002; Mesnick, Allen, Dixson and Anderson, in prep..

Project Title: Behavior of Eastern Tropical Pacific Dolphins Relative to Research Vessels
Collaborators: Anne Allen and Eric Archer (NOAA Fisheries)
Dates: 2000 - present
Funding Agency: International Dolphin Conservation Act, Protected Resources, NOAA Fisheries
Overview: This is a ship-based project based on multiple years of Southwest Fisheries Science Center survey cruises and the behavioral observations of the marine mammal observers. Results suggest a link between recent fishing activity by the tuna purse-seine fishery and population level effects on dolphins -- targeted species have a greater tendency to exhibit behaviors that may lead to the separation of mothers and calves and physical exertion.
Publications: a series of NOAA Administrative and congressional reports; Mesnick, Archer and Allen, submitted.

Selected publications:

Perrin, W.F. and Mesnick, S.L. 2003. Sexual ecology of the spinner dolphin, Stenella longirostris:, geographic variation in mating system. Marine Mammal Science, 19(3):462-483

Mesnick, S.L., Evans, K. Taylor, B.L., Hyde, J., Escorza-Trevino, S and Dizon, A.E. 2003. Sperm Whale Social Structure: Why it Takes a Village to Raise a Child. In, Animal Social Complexity: Intelligence, Culture and Individualized Societies (F.B.M. de Waal and P.L. Tyack, eds.). Harvard University Press. Pp. 170-174.

Whitehead, H. and Mesnick, S.L. 2003. Social structure and effects of differential removals by sex in sperm whales: methodology. Working paper SC/55/O18 at the 55th Annual Meeting of the International Whaling Commission. Berlin, June 2003.

Whitehead, H. and Mesnick, S.L. 2003. Population structure and movements: genetic, acoustics and marks. Working paper SC/55/O14 at the 55th Annual Meeting of the International Whaling Commission. Berlin, June 2003.

McDonald, M.A., Hildebrand, J.A. and Mesnick, S.L. 2003. Biogeographic characterization of blue whale song worldwide: using song to identify populations. Working paper SC/55/SH7 at the 55th Annual Meeting of the International Whaling Commission. Berlin, June 2003.

Bonness, D., Clapham, P.J. and Mesnick, S.L. 2002. Life History and Reproductive Strategies. In, Marine Mammals: An Evolutionary Approach (ed., R. Hoelzel). Blackwell Science, Ltd. Pp. 278-324.

Mesnick, S.L. and Ralls, K. 2002. Mating Systems. In, Encyclopedia of Marine Mammals (eds., W. F. Perrrin, B. Wursig and H.G.M. Thewissen). Academic Press. Pp 726 - 733.

Ralls, K and Mesnick, S.L. 2002. Sexual Dimorphism. In, Encyclopedia of Marine Mammals (eds., W.F. Perrrin, B. Wursig and H.G.M. Thewissen). Academic Press. Pp. 1071 - 1078.

Mitchell, E. A., Mesnick, S.L. and Allen, A.C. 2002. Sperm Whale Depredation in the Demersal Longline Fishery for Sablefish, Anaplopoma fimbria, in the Gulf of Alaska: Research Needs and Approaches to Mitigation. Working Paper for the Workshop on Cetacean Interactions with Commercial Longline Fisheries in the South Pacific Region: Approaches to Mitigation, Apia, Samoa, November 2002.

Mesnick, S. L., Archer, F. I., Allen, A. C., and Dizon, A.E. 2002. Evasive behavior of eastern tropical pacific dolphins relative to effort by the tuna purse-seine fishery. National Marine Fisheries Service Administrative Report LJ-02-30.

Mesnick, S.L. 2001. Genetic Relatedness in Sperm Whales: Evidence and Cultural Implications. Behavior and Brain Science 24(2):346-347.

Gendron, D. and Mesnick, S. L. 2001. Sloughed skin: a method for the systematic collection of tissue samples from Baja California blue whales. Journal of Cetacean Research and Management 3:77-79.

Pitman, R.L., Ballance, L.T., Mesnick, S.L. and Chivers, S. 2001. Killer Whale Predation on Sperm Whales: Observations and Implications for Large Whale Biology. Marine Mammal Science: 17(3):494-507.

Mesnick, S.L., Clapham, P.J. and Dizon, A.E. 1999. The Collection of Associated Behavioral Data with Biopsy Samples during Cetacean Assessment Cruises. Journal of Cetacean Research and Management 1(2): 205-211.

Mesnick, S. L., Taylor, B.L., Le Duc, R.G., Escorza Trevino, S., O'Corry-Crowe, G.M. and Dizon, A.E. 1999. Culture and Genetic Evolution in Whales. Science, 284: 2055a

Mesnick, S.L., Garcia Rivas, M. and Le Boeuf, B.J. 1998. Northern Elephant Seals in the Gulf of California, Mexico. Marine Mammal Science, 14(1): 171-178.

Mesnick, S.L. 1997. Sexual Alliances: Evidence and Evolutionary Implications. In, Feminism and Evolutionary Biology: Boundaries, Intersections and Frontiers (ed., P.A. Gowaty). Chapman and Hall: New York. Pp. 207-260.

Wilson, M. and S.L. Mesnick. 1997. An Empirical Test of the Bodyguard Hypothesis. In, Feminism and Evolutionary Biology: Boundaries, Intersections and Frontiers (P.A. Gowaty, ed.). Chapman and Hall: New York. Pp. 505-511.

Mesnick, S.L. and B.J. Le Boeuf. 1991. Sexual Behavior of Male Northern Elephant Seals: II. Female Response to Potentially Injurious Encounters. Behavior, 117(3-4): 262-280.

Le Boeuf, B.J. and S.L. Mesnick. 1990. Sexual Behavior of Male Northern elephant seals: I. Lethal injuries to Adult Females. Behavior, 116(1-2): 143-162.