Elephant Seals – Beltran Lab

Overview:
In collaboration with Dr. Dan Costa and his lab, our research focuses on northern elephant seals Mirounga angustirostris at Año Nuevo Reserve (37.1°N, 122.3°W) through an agreement with the California State Parks. We currently work under a National Marine Fisheries Services research permit (current version #23188) and approval from the UC Santa Cruz Institutional Animal Care and Use Committee (current version #Costd2009).

Most of our work occurs during the breeding season (~December 15 through April 01) and molting season (April 15 through July 01). While the goals of the program change with funding sources, personnel, and research novelty, the overarching goal of the program is to maintain a population of known individuals for demographic monitoring and for strategic instrumentation. This requires frequent observations of known individuals throughout their lives, which requires 3 parallel field efforts:

Weaner weighing (to weigh and flipper tag young-of-the-year seals; N~=7,000 seals total)
Flipper tag resighting (to observe flipper tagged animals and add/observe dye marks on the fur; N~= 220,000 observations of 28,000 seals total).
Instrumentation procedures (to weigh, measure, sample, and instrument seals; N~=700 seals total)

Current funded projects > $50K:

Assessment of the Cumulative Effects of Multiple Stressors on Marine Mammals– Elephant Seals as a Model System. Strategic Environmental Research and Development Program. 2020-2024, $1,854,858 (Costa/Crocker/McDonald/Peterson)
Developing Metrics of Animal Condition and their linkage to Vital Rates: Further Development of the PCoD Model. Office of Naval Research. 2018-2021. $747,826 (Costa/Crocker/Robinson/Huckstadt)
Rules of death across ontogeny in sexually dimorphic mammals. National Science Foundation. 2021-2025. $1,203,543 (Beltran/Costa)
A novel acoustic recorder for eavesdropping on the ocean soundscape. Beckman Foundation. 2021-2025. $600,000 (Beltran)

Graduate and undergraduate students often support the long-term effort while undertaking a particular research project on existing or new data. Current and future projects include:

Fitness (birth rates, death rates, recruitment, lifetime reproductive success of individuals)
Population dynamics and trends (abundance, sex ratio, age structure, cohort effects)
Foraging success (body condition gains, weaner weights)
Life history phenology (birth timing, molt timing, carry-over effects, foraging trip duration)
Animal quality (male dominance, female lifetime reproductive success)
At-sea behavior (movement, diving, diet)
Relationships between individuals (pedigree, heritability of traits)
Environmental controls (impacts of El Niño and oceanographic conditions)
Geographic distribution (immigration, emigration, fine-scale spatial use)
Handling impacts (mandated by NMFS marine mammal permit)

Research findings to date:
All publications from Año Nuevo (most focus on elephant seals) can be found here. A synopsis of research findings on northern elephant seals are below.

Research on northern elephant seals has evolved from simple land-based studies of abundance to complex analyses of at-sea spatial utilization relative to oceanographic features. Research in the 1960s focused predominantly on describing the geographic distribution, abundance (Orr, Poulter et al. 1965), and on-land behavior of elephant seals (Fogden 1968, Le Boeuf and Peterson 1969, Condit, Reiter et al. 2014, Le Boeuf, Condit et al. 2019). In the 1970s, research efforts delved deeper into social behavior (Le Boeuf, Whiting et al. 1972, Le Boeuf 1974), genetic variation (Bonnell and Selander 1974), morphology (Briggs and Morejohn 1975), ontogeny (Reiter, Stinson et al. 1978), and descriptions of basic physiology, including milk composition (Le Boeuf and Ortiz 1977) and energy influx (Ortiz, Costa et al. 1978). The 1980s were characterized by advancements in field physiology, such as measurements of blood chemistry (Costa and Ortiz 1982) and at-sea energetics (Huntley and LeBoeuf 1989), along with rudimentary investigations of at-sea behavior and fidelity (Condit and Le Boeuf 1984). Research in the 1990s focused on population demography (Reiter and Le Boeuf 1991), method development such as photogrammetry (Haley, Deutsch et al. 1991) and body condition measurements (Webb, Crocker et al. 1998), as well as the experimental translocation paradigm (Oliver, Morris et al. 1998) and broad at-sea movement (Le Boeuf, Crocker et al. 2000).

During this same time, innovations in technology provided unprecedented insight into the cryptic at-sea lives of elephant seals (Costa 1993), including their fine-scale diving behavior (Le Boeuf, Crocker et al. 1993) and association with oceanographic features and bathymetry (Simmons, Crocker et al. 2007). Findings in the 2000s led to breakthroughs in at-sea physiology (Le Boeuf, Crocker et al. 2000, Williams, Davis et al. 2000, Williams 2001, Meir and Ponganis 2010, Meir, Robinson et al. 2013), investigations into elephant seal predators (Le Boeuf 2004) and prey (Goetsch, Conners et al. 2018), fasting physiology (Houser and Costa 2001, Noren, Crocker et al. 2003), combinations of factors such as maternal traits and reproductive effort (Crocker, Williams et al. 2001), diving physiology (Thornton, Spielman et al. 2001), and a better understanding of human effects from sound sources (Costa, Crocker et al. 2003) and climate change (Le Boeuf and Crocker 2005, Crocker, Costa et al. 2006). In the past decade, we have gained valuable insights into the utilization of physical habitats (Maxwell, Frank et al. 2012) and oceanographic conditions, the mesopelagic ecosystem, intraspecific variation in behavior (Robinson, Costa et al. 2012), stress physiology (Vázquez-Medina, Crocker et al. 2010, Champagne, Houser et al. 2012), sensory biology and cognition (Casey, Reichmuth et al. 2013, Casey, Charrier et al. 2015), ontogeny (Casey, Charrier et al. 2020), and conservation applications relevant to marine megafauna on a global scale (Block, Jonsen et al. 2011, Hazen, Jorgensen et al. 2013, Maxwell, Hazen et al. 2013, Hazen, Abrahms et al. 2019).

Innovations in research methodologies along with the long-term monitoring programs in elephant seals have played a critical role in facilitating scientific investigations of other marine mammal species. For example, elephant seals were used to develop chemical immobilization (Briggs, Henrickson et al. 1977) and diet determination (Beltran, Sadou et al. 2015, Spurlin, Peterson et al. 2019) techniques that are now widely used. Elephant seals have also played an essential role in understanding the effects of biologger attachment on energetics and survival (McMahon, Field et al. 2008, Maresh, Simmons et al. 2014) and providing sample size recommendations for large marine vertebrate studies (Harrison 2012, Sequeira, Heupel et al. 2019). A suite of breakthrough technologies has been developed using elephant seals, from time-depth recorders (LeBoeuf, Costa et al. 1986), acoustic recorders and playback instruments (Costa, Crocker et al. 2003, Fregosi, Klinck et al. 2016), to stomach temperature pills (Kuhn, Crocker et al. 2009), heart rate loggers (Andrews, Jones et al. 1997), blood temperature thermistors (Meir and Ponganis 2010), respiratory frequency tags (Andrews, Costa et al. 2000), and oceanographic instruments (Boehlert, Costa et al. 2001). Validating new analytical techniques including errors associated with ARGOS satellite location (Costa, Robinson et al. 2010) and light-level geolocation (Delong, Stewart et al. 1992) methods have allowed the application of new technologies to other species. Many of the technical and procedural innovations developed in elephant seals are widely used in other species and taxa (Huntley, Costa et al. 1987).

Literature Cited:

Andrews, R. D., D. P. Costa, B. J. Le Boeuf and D. R. Jones (2000). “Breathing frequencies of northern elephant seals at sea and on land revealed by heart rate spectral analysis.” Respiration physiology 123(1-2): 71-85.
Andrews, R. D., D. Jones, J. Williams, P. Thorson, G. Oliver, D. Costa and B. Le Boeuf (1997). “Heart rates of northern elephant seals diving at sea and resting on the beach.” Journal of Experimental Biology 200(15): 2083-2095.
Beltran, R. S., M. Sadou, R. Condit, S. Peterson, C. Reichmuth and D. Costa (2015). “Fine-scale whisker growth measurements can reveal temporal foraging patterns from stable isotope signatures.” Marine Ecology Progress Series 523: 243-253.
Block, B. A., I. D. Jonsen, S. J. Jorgensen, A. J. Winship, S. A. Shaffer, S. J. Bograd, E. L. Hazen, D. G. Foley, G. Breed and A. Harrison (2011). “Tracking apex marine predator movements in a dynamic ocean.” Nature 475(7354): 86.
Boehlert, G. W., D. P. Costa, D. E. Crocker, P. Green, T. O’Brien, S. Levitus and B. J. Le Boeuf (2001). “Autonomous pinniped environmental samplers: using instrumented animals as oceanographic data collectors.” Journal of atmospheric and oceanic technology 18(11): 1882-1893.
Bonnell, M. L. and R. K. Selander (1974). “Elephant seals: genetic variation and near extinction.” Science 184(4139): 908-909.
Briggs, G. D., R. V. Henrickson and B. J. Le Boeuf (1977). Ketamine immobilization of northern elephant seals, JAVMA.
Briggs, K. and G. V. Morejohn (1975). “Sexual dimorphism in the mandibles and canine teeth of the northern elephant seal.” Journal of Mammalogy 56(1): 224-231.
Casey, C., I. Charrier, N. Mathevon, C. Nasr, P. Forman and C. Reichmuth (2020). “The genesis of giants: behavioural ontogeny of male northern elephant seals.” Animal Behaviour 166: 247-259.
Casey, C., I. Charrier, N. Mathevon and C. Reichmuth (2015). “Rival assessment among northern elephant seals: evidence of associative learning during male–male contests.” Royal Society Open Science 2(8): 150228.
Casey, C., C. Reichmuth, S. Fregosi, I. Charrier and N. Mathevon (2013). “The acoustic signature of the male northern elephant seal: individual variation supports recognition during competitive interactions.” The Journal of the Acoustical Society of America 134(5): 3988-3988.
Champagne, C. D., D. S. Houser, D. P. Costa and D. E. Crocker (2012). “The effects of handling and anesthetic agents on the stress response and carbohydrate metabolism in northern elephant seals.” PloS one 7(5): e38442.
Condit, R. and B. J. Le Boeuf (1984). “Feeding habits and feeding grounds of the northern elephant seal.” Journal of Mammalogy 65(2): 281-290.
Condit, R., J. Reiter, P. A. Morris, R. Berger, S. G. Allen and B. J. Le Boeuf (2014). “Lifetime survival rates and senescence in northern elephant seals.” Marine Mammal Science 30(1): 122-138.
Costa, D. P. (1993). “The secret life of marine mammals novel tools for studying their behavior and biology at sea.” Oceanography 6(3): 120-128.
Costa, D. P., D. E. Crocker, J. Gedamke, P. M. Webb, D. S. Houser, S. B. Blackwell, D. Waples, S. A. Hayes and B. J. Le Boeuf (2003). “The effect of a low-frequency sound source (acoustic thermometry of the ocean climate) on the diving behavior of juvenile northern elephant seals, Mirounga angustirostris.” The Journal of the Acoustical Society of America 113(2): 1155-1165.
Costa, D. P. and C. Ortiz (1982). “Blood chemistry homeostasis during prolonged fasting in the northern elephant seal.” American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 242(5): R591-R595.
Costa, D. P., P. W. Robinson, J. P. Arnould, A.-L. Harrison, S. E. Simmons, J. L. Hassrick, A. J. Hoskins, S. P. Kirkman, H. Oosthuizen and S. Villegas-Amtmann (2010). “Accuracy of ARGOS locations of pinnipeds at-sea estimated using Fastloc GPS.” PloS one 5(1).
Crocker, D. E., D. P. Costa, B. J. Le Boeuf, P. M. Webb and D. S. Houser (2006). “Impact of El Niño on the foraging behavior of female northern elephant seals.” Marine Ecology Progress Series 309.
Crocker, D. E., J. D. Williams, D. P. Costa and B. J. Le Boeuf (2001). “Maternal traits and reproductive effort in northern elephant seals.” Ecology 82(12): 3541-3555.
Delong, R. L., B. S. Stewart and R. D. Hill (1992). “Documenting migrations of northern elephant seals using day length.” Marine Mammal Science 8(2): 155-159.
Fogden, S. (1968). “Suckling behaviour in the grey seal (Halichoerus grypus) and the northern elephant seal (Mirounga angustirostris).” Journal of Zoology 154(4): 415-420.
Fregosi, S., H. Klinck, M. Horning, D. P. Costa, D. Mann, K. Sexton, L. A. Hückstädt, D. K. Mellinger and B. L. Southall (2016). “An animal-borne active acoustic tag for minimally invasive behavioral response studies on marine mammals.” Animal Biotelemetry 4(1): 1.
Goetsch, C., M. G. Conners, S. M. Budge, Y. Mitani, W. A. Walker, J. F. Bromaghin, S. E. Simmons, C. J. Reichmuth and D. P. Costa (2018). “Energy-rich mesopelagic fishes revealed as a critical prey resource for a deep-diving predator using quantitative fatty acid signature analysis.” Frontiers in Marine Science 5: 430.
Haley, M. P., C. J. Deutsch and B. J. L. Boeuf (1991). “A method for estimating mass of large pinnipeds.” Marine Mammal Science 7(2): 157-164.
Harrison, A.-L. (2012). A synthesis of marine predator migrations, distribution, species overlap, and use of Pacific Ocean Exclusive Economic Zones, UC Santa Cruz.
Hazen, E. L., B. Abrahms, S. Brodie, G. Carroll, M. G. Jacox, M. S. Savoca, K. L. Scales, W. J. Sydeman and S. J. Bograd (2019). “Marine top predators as climate and ecosystem sentinels.” Frontiers in Ecology and the Environment.
Hazen, E. L., S. Jorgensen, R. R. Rykaczewski, S. J. Bograd, D. G. Foley, I. D. Jonsen, S. A. Shaffer, J. P. Dunne, D. P. Costa and L. B. Crowder (2013). “Predicted habitat shifts of Pacific top predators in a changing climate.” Nature Climate Change 3(3): 234.
Houser, D. and D. Costa (2001). “Protein catabolism in suckling and fasting northern elephant seal pups (Mirounga angustirostris).” Journal of Comparative Physiology B 171(8): 635-642.
Huntley, A., D. Costa, G. Worthy and M. Castellini (1987). Approaches to Marine Mammal Energetics. Spec. Publ. 1, Society for Marine Mammalogy, Allen Press, Lawrence, KS.
Huntley, A. C. and B. J. LeBoeuf (1989). “Daily gross energy requirements of a female northern elephant seal Mirounga angustirostris at sea.” 日本水産学会誌 55(12): 2057-2063.
Kuhn, C. E., D. E. Crocker, Y. Tremblay and D. P. Costa (2009). “Time to eat: measurements of feeding behaviour in a large marine predator, the northern elephant seal Mirounga angustirostris.” Journal of Animal Ecology 78(3): 513-523.
Le Boeuf, B., R. Condit and J. Reiter (2019). “Lifetime reproductive success of northern elephant seals, Mirounga angustirostris.” Canadian Journal of Zoology.
Le Boeuf, B., D. Crocker, S. Blackwell, P. Morris and P. Thorson (1993). Sex differences in diving and foraging behaviour of northern elephant seals. Symp Zool Soc Lond.
Le Boeuf, B., D. E. Crocker, D. P. Costa, S. B. Blackwell, P. M. Webb and D. S. Houser (2000). “Foraging ecology of northern elephant seals.” Ecological Monographs 70(3): 353-382.
Le Boeuf, B. J. (1974). “Male-male competition and reproductive success in elephant seals.” American Zoologist 14(1): 163-176.
Le Boeuf, B. J. (2004). “Hunting and migratory movements of white sharks in the eastern North Pacific.”
Le Boeuf, B. J., D. Crocker, J. Grayson, J. Gedamke, P. M. Webb, S. B. Blackwell and D. P. Costa (2000). “Respiration and heart rate at the surface between dives in northern elephant seals.” Journal of Experimental Biology 203(21): 3265-3274.
Le Boeuf, B. J. and D. E. Crocker (2005). “Ocean climate and seal condition.” BMC Biology 3(1): 9.
Le Boeuf, B. J. and C. L. Ortiz (1977). “Composition of elephant seal milk.” Journal of mammalogy: 683-685.
Le Boeuf, B. J. and R. S. Peterson (1969). “Social status and mating activity in elephant seals.” Science 163(3862): 91-93.
Le Boeuf, B. J., R. J. Whiting and R. F. Gantt (1972). “Perinatal behavior of northern elephant seal females and their young.” Behaviour: 121-156.
LeBoeuf, B., D. Costa, A. Huntley, G. Kooyman and R. Davis (1986). “Pattern and depth of dives in northern elephant seals, Mirounga angustirostris.” Journal of Zoology 208(1): 1-7.
Maresh, J. L., S. E. Simmons, D. E. Crocker, B. I. McDonald, T. M. Williams and D. P. Costa (2014). “Free-swimming northern elephant seals have low field metabolic rates that are sensitive to an increased cost of transport.” Journal of Experimental Biology 217(9): 1485-1495.
Maxwell, S. M., J. J. Frank, G. A. Breed, P. W. Robinson, S. E. Simmons, D. E. Crocker, J. P. Gallo‐Reynoso and D. P. Costa (2012). “Benthic foraging on seamounts: A specialized foraging behavior in a deep‐diving pinniped.” Marine Mammal Science 28(3): E333-E344.
Maxwell, S. M., E. L. Hazen, S. J. Bograd, B. S. Halpern, G. A. Breed, B. Nickel, N. M. Teutschel, L. B. Crowder, S. Benson and P. H. Dutton (2013). “Cumulative human impacts on marine predators.” Nature communications 4: 2688.
McMahon, C. R., I. C. Field, C. J. Bradshaw, G. C. White and M. A. Hindell (2008). “Tracking and data–logging devices attached to elephant seals do not affect individual mass gain or survival.” Journal of Experimental Marine Biology and Ecology 360(2): 71-77.
Meir, J. U. and P. J. Ponganis (2010). “Blood temperature profiles of diving elephant seals.” Physiological and Biochemical Zoology 83(3): 531-540.
Meir, J. U., P. W. Robinson, L. I. Vilchis, G. L. Kooyman, D. P. Costa and P. J. Ponganis (2013). “Blood oxygen depletion is independent of dive function in a deep diving vertebrate, the northern elephant seal.” PloS one 8(12).
Noren, D. P., D. E. Crocker, T. M. Williams and D. P. Costa (2003). “Energy reserve utilization in northern elephant seal (Mirounga angustirostris) pups during the postweaning fast: size does matter.” J Comp Physiol B 173(5): 443-454.
Oliver, G. W., P. A. Morris, P. H. Thorson and B. J. le Boeuf (1998). “Homing behavior of juvenile northern elephant seals.” Marine Mammal Science 14(2): 245-256.
Orr, R. T., T. C. Poulter and G. D. Hanna (1965). The pinniped population of Año Nuevo Island, California, California Academy of Sciences.
Ortiz, C. L., D. Costa and B. J. Le Boeuf (1978). “Water and energy flux in elephant seal pups fasting under natural conditions.” Physiological Zoology 51(2): 166-178.
Reiter, J. and B. J. Le Boeuf (1991). “Life history consequences of variation in age at primiparity in northern elephant seals.” Behavioral Ecology and Sociobiology 28(3): 153-160.
Reiter, J., N. L. Stinson and B. J. Le Boeuf (1978). “Northern elephant seal development: the transition from weaning to nutritional independence.” Behavioral Ecology and Sociobiology 3(4): 337-367.
Robinson, P. W., D. P. Costa, D. E. Crocker, J. P. Gallo-Reynoso, C. D. Champagne, M. A. Fowler, C. Goetsch, K. T. Goetz, J. L. Hassrick and L. A. Hückstädt (2012). “Foraging behavior and success of a mesopelagic predator in the northeast Pacific Ocean: insights from a data-rich species, the northern elephant seal.” PLOS ONE 7(5): e36728.
Sequeira, A., M. Heupel, M. A. Lea, V. Eguíluz, C. M. Duarte, M. Meekan, M. Thums, H. Calich, R. Carmichael and D. Costa (2019). “The importance of sample size in marine megafauna tagging studies.” Ecological Applications: e01947.
Simmons, S. E., D. E. Crocker, R. M. Kudela and D. P. Costa (2007). “Linking foraging behaviour of the northern elephant seal with oceanography and bathymetry at mesoscales.” Marine Ecology Progress Series 346: 265-275.
Spurlin, S. M., S. H. Peterson, D. E. Crocker and D. P. Costa (2019). “Nitrogen and carbon stable‐isotope ratios change in adult northern elephant seals (Mirounga angustirostris) during the breeding and molting fasts.” Marine Mammal Science 35(2): 707-717.
Thornton, S. J., D. M. Spielman, N. J. Pelc, W. F. Block, D. E. Crocker, D. P. Costa, B. J. LeBoeuf and P. W. Hochachka (2001). “Effects of forced diving on the spleen and hepatic sinus in northern elephant seal pups.” Proceedings of the National Academy of Sciences 98(16): 9413-9418.
Vázquez-Medina, J. P., D. E. Crocker, H. J. Forman and R. M. Ortiz (2010). “Prolonged fasting does not increase oxidative damage or inflammation in postweaned northern elephant seal pups.” Journal of Experimental Biology 213(14): 2524-2530.
Webb, P., D. Crocker, S. Blackwell, D. Costa and B. Boeuf (1998). “Effects of buoyancy on the diving behavior of northern elephant seals.” Journal of Experimental Biology 201(16): 2349-2358.
Williams, T. M. (2001). “Intermittent swimming by mammals: a strategy for increasing energetic efficiency during diving.” American Zoologist 41(2): 166-176.
Williams, T. M., R. Davis, L. Fuiman, J. Francis, B. Le, M. Horning, J. Calambokidis and D. Croll (2000). “Sink or swim: strategies for cost-efficient diving by marine mammals.” Science 288(5463): 133-136.