Many severely depleted populations of baleen whales (Mysticeti) have exhibited clear signs of recovery whereas there are few examples in toothed whales (Odontoceti). We hypothesize that this difference is due, at least in part, to social and behavioural factors. Clearly, a part of the lack of resilience to exploitation is explained by odontocete life history. However, an additional factor may be the highly social nature of many odontocetes in which survival and reproductive success may depend on: (a) social cohesion and organization, (b) mutual defence against predators and possible alloparental care, (c) inter-generational transfer of “knowledge”, and (d) leadership by older individuals. We found little evidence of strong recovery in any of the depleted populations examined. Their relatively low potential rates of increase mean that odontocete populations can be over-exploited with take rates of only a few percent per year. Exploitation can have effects beyond the dynamics of individual removals. Four species showed evidence of a decrease in birth rates following exploitation; potential mechanisms include a deficit of adult females, a deficit of adult males, and disruption of mating systems. The evidence for a lack of strong recovery in heavily exploited odontocete populations indicates that management should be more precautionary. 1. Introduction In a 1993 paper, Best [1] examined increase rates in severely depleted stocks of baleen whales (Mysticeti). Of 44 that had been depleted to less than 10% of their original abundance, 12 were being adequately monitored to determine trends, and of those, ten exhibited significant positive rates of increase. In effect, Best concluded that there was no clear evidence for a “lag” in the response to protection (e.g., due to depensation or so-called “Allee effects”) and that apparent delays in recovery by some stocks were more likely due to the inadequacy of monitoring effort than to impaired reproduction or recruitment failure. Further, he offered the hypothesis that in many stocks “a combination of range retraction and underestimation of the extent of depletion has hindered detection of a recovery.” In the nearly 20 years since Best’s analysis, a number of the 32 severely depleted stocks that he judged to have been inadequately monitored have now shown clear signs of increase. For example, there is evidence for increases in blue whale (Balaenoptera musculus) abundance [2] in the Antarctic and fin whale (Balaenoptera physalus) abundance in central California [3]. Bowhead whales (Balaena mysticetus) in eastern
References
[1]
P. B. Best, “Increase rates in severely depleted stocks of baleen whales,” ICES Journal of Marine Science, vol. 50, no. 2, pp. 169–186, 1993.
[2]
T. A. Branch, K. Matsuoka, and T. Miyashita, “Evidence for increases in Antarctic blue whales based on Bayesian modelling,” Marine Mammal Science, vol. 20, no. 4, pp. 726–754, 2004.
[3]
J. E. Moore and J. Barlow, “Bayesian state-space model of fin whale abundance trends from a 1991-2008 time series of line-transect surveys in the California Current,” Journal of Applied Ecology, vol. 48, no. 5, pp. 1195–1205, 2011.
[4]
M. P. Heide-J？rgensen, K. Laidre, D. Borchers, F. Samarra, and H. Stern, “Increasing abundance of bowhead whales in West Greenland,” Biology letters, vol. 3, no. 5, pp. 577–580, 2007.
[5]
S. B. Reilly and J. Barlow, “Rates of increase in dolphin population size,” Fishery Bulletin, vol. 84, no. 3, pp. 527–533, 1986.
[6]
P. R. Wade, “Calculating limits to the allowable human-caused mortality of cetaceans and pinnipeds,” Marine Mammal Science, vol. 14, no. 1, pp. 1–37, 1998.
[7]
P. R. Wade, “Population dynamics,” in Encyclopedia of Marine Mammals, W. F. Perrin, B. Würsig, and J. G. M. Thewissen, Eds., Academic Press, San Diego, Calif, USA, 2002.
[8]
S. L. Mesnick and K. Ralls, “Mating systems,” in Encyclopedia of Marine Mammals, W. F. Perrin, B. Würsig, and J. G. M. Thewissen, Eds., Academic Press, San Diego, Calif, USA, 2002.
[9]
A. Acevedo-Gutierrez, “Group behaviour,” in Encyclopedia of Marine Mammals, W. F. Perrin, B. Würsig, and J. G. M. Thewissen, Eds., Academic Press, San Diego, Calif, USA, 2002.
[10]
J. H. Poole, “Rutting behaviour in African elephants: the phenomenon of musth,” Behaviour, vol. 102, no. 3-4, pp. 283–316, 1987.
[11]
K. McComb, C. Moss, S. M. Durant, L. Baker, and S. Sayialel, “Matriarchs as repositories of social knowledge in African elephants,” Science, vol. 292, no. 5516, pp. 491–494, 2001.
[12]
J. R. Ginsberg and E. J. Milner-Gulland, “Sex-biased harvesting and population dynamics in ungulates: implications for conservation and sustainable use,” Conservation Biology, vol. 8, no. 1, pp. 157–166, 1994.
[13]
R. B. Harris, W. A. Wall, and F. W. Allendorf, “Genetic consequences of hunting: what do we know and what should we do?” Wildlife Society Bulletin, vol. 30, no. 2, pp. 634–643, 2002.
[14]
C. T. Darimont, S. M. Carlson, M. T. Kinnison, P. C. Paquet, T. E. Reimchen, and C. C. Wilmers, “Human predators outpace other agents of trait change in the wild,” Proceedings of the National Academy of Sciences of the United States of America, vol. 106, no. 3, pp. 952–954, 2009.
[15]
D. W. Coltman, P. O'Donoghue, J. T. Jorgenson, J. T. Hogg, C. Strobeck, and M. Festa-Bianchet, “Undesirable evolutionary consequences of trophy hunting,” Nature, vol. 426, no. 6967, pp. 655–658, 2003.
[16]
H. Jachmann, P. S. Berry, and H. Imae, “Tusklessness in African elephants: a future trend,” African Journal of Ecology, vol. 33, no. 3, pp. 230–235, 1995.
[17]
R. Fergusson, A preliminary investigation of the population dynamics of sable antelope in the Matetsi Safari Area, Zimbabwe [M.S. thesis], University of Zimbabwe, Harare, Zimbabwe, 1990.
[18]
G. C. Haber, “Biological, conservation, and ethical implications of exploiting and controlling wolves,” Conservation Biology, vol. 10, no. 4, pp. 1068–1081, 1996.
[19]
B. L. Taylor, M. Martinez, T. Gerrodette, J. Barlow, and Y. N. Hrovat, “Lessons from monitoring trends in abundance of marine mammals,” Marine Mammal Science, vol. 23, no. 1, pp. 157–175, 2007.
[20]
H. Whitehead, “Density-dependent habitat selection and the modeling of sperm whale (Physeter macrocephalus) exploitation,” Canadian Journal of Fisheries and Aquatic Sciences, vol. 57, no. 1, pp. 223–230, 2000.
[21]
L. Weilgart, H. Whitehead, and K. Payne, “A colossal convergence,” American Scientist, vol. 84, no. 3, pp. 278–287, 1996.
[22]
H. Whitehead and L. Rendell, “Movements, habitat use and feeding success of cultural clans of South Pacific sperm whales,” Journal of Animal Ecology, vol. 73, no. 1, pp. 190–196, 2004.
[23]
S. L. Mesnick, K. Evans, B. L. Taylor, J. Hyde, S. Escorza-Trevino, and A. E. Dizon, “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, Cambridge, Mass, USA, 2003.
[24]
H. Whitehead, “Babysitting, dive synchrony, and indications of alloparental care in sperm whales,” Behavioral Ecology and Sociobiology, vol. 38, no. 4, pp. 237–244, 1996.
[25]
H. Whitehead, J. Christal, and S. Dufault, “Past and distant whaling and the rapid decline of sperm whales off the Galapagos Islands,” Conservation Biology, vol. 11, no. 6, pp. 1387–1396, 1997.
[26]
R. Clarke, A. Aguayo, and O. Paliza, “Pregnancy rates of sperm whales in the southeast Pacific between 1959 and 1962 and a comparison with those from Paita, Peru between 1975 and 1977,” Report of the International Whaling Commission, vol. 2, pp. 151–158, 1980.
[27]
S. L. Perry, D. P. DeMaster, and G. K. Silber, “The great whales: history and status of six species listed as endangered under the U.S. Endangered Species Act of 1973,” Marine Fisheries Review, vol. 61, no. 1, pp. 1–74, 1999.
[28]
J. Barlow, “Recent information on the status of large whales in California waters,” NOAA Technical Memorandum NMFS NOAA-TM-NMFS-SWFSC-203, U.S. Department Of Commerce, 1994.
[29]
H. Whitehead, “Estimates of the current global population size and historical trajectory for sperm whales,” Marine Ecology Progress Series, vol. 242, pp. 295–304, 2002.
[30]
R. Clarke, “Open boat whaling in the Azores,” Discovery Reports, vol. 26, pp. 281–354, 1954.
[31]
International Whaling Commission, “Report of the subcommittee on sperm whales,” Report of the International Whaling Commission, vol. 32, pp. 68–86, 1982.
[32]
G. O’Corry-Crowe, “Beluga whales,” in Encyclopedia of Marine Mammals, W. F. Perrin, B. Würsig, and J. G. M. Thewissen, Eds., Academic Press, San Diego, Calif, USA, 2002.
[33]
T. G. Smith, M. O. Hammill, and A. R. Martin, “Herd composition & behaviour of white whales (Delphinapterus leucas) in two Canadian Arctic estuaries,” Meddelelser om. Gr？nland, Bioscience, vol. 39, pp. 175–186, 1994.
[34]
D. E. Sergeant and P. F. Brodie, “Identity, abundance, and present status of populations of white whales, Delphinapterus leucas,” Journal of the Fisheries Research Board of Canada, vol. 32, pp. 1047–1054, 1975.
[35]
D. E. Sergeant, “On permissible expoitation rates of Monodontidae,” Report of the International Whaling Commission, vol. 31, pp. 583–588, 1981.
[36]
M. Kingsley, “Population dynamics of the narwhal Monodon monoceros: an initial assessment (Odontoceti: Monodontidae),” Journal of Zoology, vol. 219, no. 2, pp. 201–208, 1989.
[37]
R. R. Reeves and E. Mitchell, “Catch history, former abundance, and distribution of white whales in Hudson Strait and Ungava Bay,” Naturaliste Canadien, vol. 114, no. 1, pp. 1–65, 1987.
[38]
M. P. Heide-J？rgensen, “Distribution, exploitation and population status of white whales (Delphinapterus leucas) and narwhals (Monodon monoceros) in West Greenland,” Meddelelser om. Gr？nland, Bioscience, vol. 39, pp. 135–149, 1994.
[39]
E. Mitchell, Porpoise, Dolphin and Small Whale Fisheries of the World: Status and Problems, vol. 3 of IUCN Monograph, International Union for Conservation of Nature and Natural Resources, Morges, Switzerland, 1975.
[40]
R. C. Hobbs, D. J. Rugh, and D. P. Demaster, “Abundance of belugas, Delphinapterus leucas, in Cook Inlet, Alaska, 1994–2000,” Marine Fisheries Review, vol. 62, no. 3, pp. 37–45, 2000.
[41]
R. C. Hobbs, K. E. W. Shelden, D. J. Vos, K. T. Goetz, and D. J. Rugh, “Status review and extinction assessment of Cook Inlet belugas (Delphinapterus leucas),” Alaska Fisheries Science Center Report AFSC-PR-2006-16, NOAA National Marine Fisheries Service, Seattle, Wash, USA, 2006.
[42]
R. R. Reeves and E. Mitchell, “Catch history and initial population of white whales (Delphinapterus leucas) in the river and Gulf of St. Lawrence, eastern Canada,” Naturaliste Canadien, vol. 111, no. 1, pp. 63–121, 1984.
[43]
M. O. Hammill, L. N. Measures, J.-F. Gosselin, and V. Lesage, “Lack of recovery in St. Lawrence Estuary beluga,” Science Advisory Secretariat Research Document 2007/026, 2007.
[44]
L. Lowry, G. O’Corry-Crowe, and D. Goodman, “Delphinapterus leucas (Cook Inlet population),” in 2006 IUCN Red List of Threatened Species, IUCN, Gland, Switzerland, 2006.
[45]
L. F. Lowry, K. J. Frost, A. Zerbini, D. DeMaster, and R. R. Reeves, “Trend in aerial counts of beluga1 or white whales (Delphinapterus leucas) in Bristol Bay, Alaska, 1993–2005,” Journal of Cetacean Research and Management, vol. 10, no. 3, pp. 201–207, 2008.
[46]
H. B. Gerson and J. P. Hickie, “Head scarring on male narwhals (Monodon monoceros): evidence for aggressive tusk use,” Canadian Journal of Zoology, vol. 63, no. 9, pp. 2083–2087, 1985.
[47]
NAMMCO/JCNB, “Annex 1. Joint meeting of the NAMMCO Scientific Committee Working Group on the Population Status of Narwhal and Beluga in the North Atlantic and the Canada/Greenland Joint Commission on Conservtion and Management of Narwhal and Beluga Scientific Working Group, Nuuk, Greenland, 13-16 October 2005,” Annual Report 2005, North Atlantic Marine Mammal Commission, 2006.
[48]
M. P. Heide-J？rgensen, “Aerial digital photographic surveys of narwhals, Monodon monoceros, in Northwest Greenland,” Marine Mammal Science, vol. 20, no. 2, pp. 246–261, 2004.
[49]
M. P. Heide-J？rgensen and M. Acquarone, “Size and trends of the bowhead whale, beluga and narwhal stocks off West Greenland,” NAMMCO Scientific Publications, vol. 4, pp. 191–210, 2002.
[50]
NAMMCO/JCNB, “Report of the Joint Meeting of the NAMMCO Scientific Committee Working Group on the Population Status of Narwhal and Beluga in the North Atlantic and the Canada/Greenland Joint Commission on Conservation and Management of Narwhal and Beluga Scientific Working Group, Winnipeg, Canada, 17–20 February 2009,” Annual Report 2009, North Atlantic Marine Mammal Commission, 2009.
[51]
R. R. Reeves, What is a narwhal worth? An analysis of factors driving the narwhal hunt and a critique of tried approaches to hunt management [Ph.D. thesis], McGill University, Montreal, Canada, 1992.
[52]
K. L. Laidre and M. P. Heide-J？rgensen, “Arctic sea ice trends and narwhal vulnerability,” Biological Conservation, vol. 121, no. 4, pp. 509–517, 2005.
[53]
K. Laidre, M. P. Heide-J？rgensen, H. Stern, and P. Richard, “Unusual narwhal sea ice entrapments and delayed autumn freeze-up trends,” Polar Biology, vol. 35, pp. 149–154, 2011.
[54]
P. F. Olesiuk, M. A. Bigg, and G. M. Ellis, “Life history and population dynamics of resident killer whales (Orcinus orca) in the coastal waters of British Columbia and Washington State,” Report of the International Whaling Commission, vol. 12, pp. 209–243, 1990.
[55]
R. L. Pitman and P. Ensor, “Three forms of killer whales (Orcinus orca) in Antarctic waters,” Journal of Cetacean Research and Management, vol. 5, pp. 131–139, 2003.
[56]
J. K. B. Ford, G. M. Ellis, and K. C. Balcomb, Killer Whales: The Natural History and Genealogy of Orcinus orca in British Columbia and Washington, University of Washington, Seattle, Wash, USA, 2nd edition, 2000.
[57]
M. A. Bigg, P. F. Olesiuk, G. M. Ellis, J. K. B. Ford, and K. C. Balcomb, “Social organization and genealogy of resident killer whales (Orcinus orca) in the coastal waters of British Columbia and Washington State,” Report of the International Whaling Commission, vol. 12, pp. 383–405, 1990.
[58]
J. K. B. Ford, “Vocal traditions among resident killer whales (Orcinus orca) in coastal waters of British Columbia,” Canadian Journal of Zoology, vol. 69, no. 6, pp. 1454–1483, 1991.
[59]
H. Yurk, “Do killer whales have culture?” in Animal Social Complexity: Intelligence, Culture, and Individualized Societies, F. B. M. de Waal and P. L. Tyack, Eds., Harvard University, Cambridge, Mass, USA, 2003.
[60]
J. C. López and D. López, “Killer whales of Patagonia and their behavior of intentional stranding while hunting nearshore,” Journal of Mammalogy, vol. 66, pp. 181–183, 1985.
[61]
E. Hoyt, The Whale Called Killer, E P Dutton, New York, NY, USA, 1990.
[62]
M. M. Krahn, P. R. Wade, S. T. Kalinowski et al., “Status review of southern resident killer whales (Orcinus orca) under the Endangered Species Act,” NOAA Technical Memorandum NMFS NOAA-TM-NMFS-NWFSC-54, U.S. Department Of Commerce, 2002.
[63]
J. K. B. Ford, G. M. Ellis, P. F. Olesiuk, and K. C. Balcomb, “Linking killer whale survival and prey abundance: food limitation in the oceans' apex predator?” Biology Letters, vol. 6, no. 1, pp. 139–142, 2010.
[64]
P. S. Ross, G. M. Ellis, M. G. Ikonomou, L. G. Barrett-Lennard, and R. F. Addison, “High PCB concentrations in free-ranging Pacific killer whales, Orcinus orca: effects of age, sex and dietary preference,” Marine Pollution Bulletin, vol. 40, no. 6, pp. 504–515, 2000.
[65]
M. M. Krahn, M. B. Hanson, R. W. Baird et al., “Persistent organic pollutants and stable isotopes in biopsy samples (2004/2006) from Southern Resident killer whales,” Marine Pollution Bulletin, vol. 54, no. 12, pp. 1903–1911, 2007.
[66]
M. M. Krahn, M. Bradley Hanson, G. S. Schorr et al., “Effects of age, sex and reproductive status on persistent organic pollutant concentrations in “Southern Resident” killer whales,” Marine Pollution Bulletin, vol. 58, no. 10, pp. 1522–1529, 2009.
[67]
M. M. Krahn, M. J. Ford, W. F. Perrin et al., “2004 Status review of Southern Resident killer whales (Orcinus orca) under the Endangered Species Act,” NOAA Technical Memorandum NMFS NOAA-TM-NMFS-NWFSC-62, U.S. Department Of Commerce, 2004.
[68]
P. F. Olesiuk, G. M. Ellis, and J. K. B. Ford, “Life history and population dynamics of northern resident killer whales (Orcinus orca) in British Columbia,” DFO Canadian Science Advisory Secretariat Research Document 2005/045, 2005.
[69]
C. O. Matkin, E. L. Saulitis, G. M. Ellis, P. Olesiuk, and S. D. Rice, “Ongoing population-level impacts on killer whales Orcinus orca following the “Exxon Valdez” oil spill in Prince William Sound, Alaska,” Marine Ecology Progress Series, vol. 356, pp. 269–281, 2008.
[70]
D. Lusseau and M. E. J. Newman, “Identifying the role that animals play in their social networks,” Proceedings of the Royal Society B, vol. 271, no. 6, pp. S477–S481, 2004.
[71]
R. Williams and D. Lusseau, “A killer whale social network is vulnerable to targeted removals,” Biology Letters, vol. 2, no. 4, pp. 497–500, 2006.
[72]
G. M. Ylitalo, C. O. Matkin, J. Buzitis et al., “Influence of life-history parameters on organochlorine concentrations in free-ranging killer whales (Orcinus orca) from Prince William Sound, AK,” Science of the Total Environment, vol. 281, no. 1-3, pp. 183–203, 2001.
[73]
J. M. Ver Hoef and K. J. Frost, “A bayesian hierarchical model for monitoring harbor seal changes in Prince William Sound, Alaska,” Environmental and Ecological Statistics, vol. 10, no. 2, pp. 201–219, 2003.
[74]
P. A. Olson and S. B. Reilly, “Pilot whales,” in Encyclopedia of Marine Mammals, W. F. Perrin, B. Würsig, and J. G. M. Thewissen, Eds., Academic Press, San Diego, Calif, USA, 2002.
[75]
B. Amos, C. Schlotterer, and D. Tautz, “Social structure of pilot whales revealed by analytical DNA profiling,” Science, vol. 260, no. 5108, pp. 670–672, 1993.
[76]
H. Marsh and T. Kasuya, “Evidence for reproductive senescence in female cetaceans,” Report of the International Whaling Commission, vol. 8, pp. 57–74, 1986.
[77]
D. Bloch, C. Lockyer, and M. Zachariassen, “Age and growth parameters of the long-finned pilot whale off the Faroe Islands,” Report of the International Whaling Commission, vol. 14, pp. 163–207, 1993.
[78]
H. Marsh and T. Kasuya, “Changes in the role of a female pilot whale with age,” in Dolphin Societies, K. Pryor and K. S. Norris, Eds., University of California, Berkeley, Calif, USA, 1991.
[79]
A. D. Foote, “Mortality rate acceleration and post-reproductive lifespan in matrilineal whale species,” Biology Letters, vol. 4, no. 2, pp. 189–191, 2008.
[80]
K. S. Norris and K. Pryor, “Some thoughts on grandmothers,” in Dolphin Societies, K. Pryor and K. S. Norris, Eds., University of California, Berkeley, Calif, USA, 1991.
[81]
A. Aguilar, L. Jover, and A. Borrell, “Heterogeneities in organochlorine profiles of Faroese long-finned pilot whales: indication of segregation between pods?” Report of the International Whaling Commission, vol. 14, pp. 359–367, 1993.
[82]
F. Caurant, C. Amiard-Triquet, and J.-C. Amiard, “Factors influencing the accumulation of metals in pilot whales (Globicephala melas) off the Faroe Islands,” Report of the International Whaling Commission, vol. 14, pp. 369–390, 1993.
[83]
J. A. Balbuena, F. J. Aznar, M. Fernández, and J. A. Raga, “Parasites as indicators of social structure and stock identity of marine mammals,” in Whales, Seals, Fish and Man, A. S. Blix, L. Wall？e, and ？. Ulltang, Eds., Elsevier Science BV, Amsterdam, The Netherlands, 1995.
[84]
S. T. Buckland, D. Bloch, K. L. Cattanach et al., “Distribution and abundance of long-finned pilot whales in the North Atlantic, estimated from NASS-1987 and NASS-89 data,” Report of the International Whaling Commission, vol. 14, pp. 33–50, 1993.
[85]
M. C. Mercer, “Modified Leslie-Delury population models of the long-finned pilot whale (Globicephala melas) and annual production of short-finned squid (Illex illecebrosus) based upon their interaction in Newfoundland,” Journal of the Fisheries Research Board of Canada, vol. 32, pp. 1145–1154, 1975.
[86]
K. Hay, “Aerial line-transect estimates of abundance of humpback, fin, and long-finned pilot whales in the Newfoundland-Labrador area,” Report of the International Whaling Commission, vol. 32, pp. 475–486, 1982.
[87]
D. Nelson and J. Lien, “The status of the long-finned Pilot Whale, Globicephala melas, in Canada,” Canadian Field-Naturalist, vol. 110, no. 3, pp. 511–524, 1996.
[88]
D. E. Sergeant, “The biology of the pilot or pothead whale Globicephala melaena (Traill) in Newfoundland waters,” Fisheries Research Board of Canada. Bulletin, vol. 132, pp. 1–84, 1962.
[89]
T. Kishiro and T. Kasuya, “Review of Japanese dolphin drive fisheries and their status,” Report of the International Whaling Commission, vol. 43, pp. 439–452, 1993.
[90]
T. Kasuya, “Japanese whaling and other cetacean fisheries,” Environmental Science and Pollution Research, vol. 14, no. 1, pp. 39–48, 2007.
[91]
R. C. Connor, R. A. Smolker, and A. F. Richards, “Two levels of alliance formation among male bottlenose dolphins (Tursiops sp.),” Proceedings of the National Academy of Sciences of the United States of America, vol. 89, no. 3, pp. 987–990, 1992.
[92]
R. C. Connor, M. R. Heithaus, and L. M. Barre, “Complex social structure, alliance stability and mating access in a bottlenose dolphin “super-alliance”,” Proceedings of the Royal Society B, vol. 268, no. 1464, pp. 263–267, 2001.
[93]
C. A. Rogers, B. J. Brunnick, D. L. Herzing, and J. D. Baldwin, “The social structure of bottlenose dolphins, Tursiops truncatus, in the Bahamas,” Marine Mammal Science, vol. 20, no. 4, pp. 688–708, 2004.
[94]
K. S. Norris, B. Würsig, R. S. Wells, and M. Würsig, The Hawaiian Spinner Dolphin, University of California, Berkeley, Calif, USA, 1994.
[95]
W. F. Perrin, “Using porpoise to catch tuna,” World Fishing, vol. 18, pp. 42–45, 1969.
[96]
J. Joseph and J. W. Greenough, International Management of Tuna, Porpoise, and Billfish, University of Washington, London, UK, 1979.
[97]
S. B. Reilly, M. A. Donahue, T. Gerrodette, et al., “Report of the scientific research program under the International Dolphin Conservation Program Act,” NOAA Technical Memorandum NMFS NOAA-TM-NMFS-SWFSC-372, U.S. Department Of Commerce, 2005, http://swfsc.noaa.gov/publications/TM/SWFSC/NOAA-TM-NMFS-SWFSC-372.PDF.
[98]
P. R. Wade, “Revised estimates of incidental kill of dolphins (Delphinidae) by the purse-seine tuna fishery in the eastern tropical Pacific, 1959-1972,” Fishery Bulletin, vol. 93, no. 2, pp. 345–354, 1995.
[99]
P. R. Wade, G. M. Watters, T. Gerrodette, and S. B. Reilly, “Depletion of spotted and spinner dolphins in the eastern tropical Pacific: modeling hypotheses for their lack of recovery,” Marine Ecology Progress Series, vol. 343, pp. 1–14, 2007.
[100]
K. Pryor and I. K. Shallenberger, “Social structure in spotted dolphins (Stenella attenuata) in the tuna purse seine fishery in the eastern tropical Pacific,” in Dolphin Societies, K. Pryor and K. S. Norris, Eds., University of California, Berkeley, Calif, USA, 1991.
[101]
T. Gerrodette and J. Forcada, “Non-recovery of two spotted and spinner dolphin populations in the eastern tropical Pacific Ocean,” Marine Ecology Progress Series, vol. 291, pp. 1–21, 2005.
[102]
F. Archer, T. Gerrodette, A. Dizon, K. Abella, and S. Southern, “Unobserved kill of nursing dolphin calves in a tuna purse-seine fishery,” Marine Mammal Science, vol. 17, no. 3, pp. 540–554, 2001.
[103]
P. C. Perkins and E. F. Edwards, “Capture rate as a function of school size in pantropical spotted dolphins, Stenella attenuata, in the eastern tropical Pacific Ocean,” Fishery Bulletin, vol. 97, no. 3, pp. 542–554, 1999.
[104]
B. E. Curry, “Stress in mammals: the potential influence offishery-induced stress on dolphins in the eastern tropical Pacific Ocean,” NOAA Technical Memorandum NMFS NOAA-TM-NMFS-SWFSC-260, U.S. Department Of Commerce, 1994.
[105]
W. L. Perryman and T. C. Foster, “Preliminary report of predation by small whales, mainly the false killer whale, Pseudorca crassidens, on dolphins (Stenella spp and Delphinus delphis) in the eastern tropical Pacific,” NOAA Admin Report LJ-80-05, La Jolla, Calif, USA, 1980.
[106]
E. F. Edwards, “Duration of unassisted swimming activity for spotted dolphin (Stenella attenuata) calves: implications for mother-calf separation during tuna purse-seine sets,” Fishery Bulletin, vol. 104, no. 1, pp. 125–135, 2006.
[107]
S. R. Noren and E. F. Edwards, “Physiological and behavioral development in delphinid calves: implications for calf separation and mortality due to tuna purse-seine sets,” Marine Mammal Science, vol. 23, no. 1, pp. 15–29, 2007.
[108]
F. Archer, T. Gerrodette, S. Chivers, and A. Jackson, “Annual estimates of the unobserved incidental kill of pantropical spotted dolphin (Stenella attenuata attenuata) calves in the tuna purse-seine fishery of the eastern tropical Pacific,” Fishery Bulletin, vol. 102, no. 2, pp. 233–244, 2004.
[109]
W. F. Perrin and S. L. Mesnick, “Sexual ecology of the spinner dolphin, Stenella longirostris: geographic variation in mating system,” Marine Mammal Science, vol. 19, no. 3, pp. 462–483, 2003.
[110]
K. L. Cramer, W. L. Perryman, and T. Gerrodette, “Declines in reproductive output in two dolphin populations depleted by the yellowfin tuna purse-seine fishery,” Marine Ecology Progress Series, vol. 369, pp. 273–285, 2008.
[111]
P. B. Best, P. A. S. Canham, and N. MacLeod, “Patterns of reproduction in sperm whales, Physeter macrocephalus,” Report of the International Whaling Commission, vol. 6, pp. 51–79, 1984.
[112]
A. J. Read and P. R. Wade, “Status of marine mammals in the United States,” Conservation Biology, vol. 14, no. 4, pp. 929–940, 2000.
[113]
A. J. Read, “The looming crisis: interactions between marine mammals and fisheries,” Journal of Mammalogy, vol. 89, no. 3, pp. 541–548, 2008.
[114]
A. J. Read, P. Drinker, and S. Northridge, “Bycatch of marine mammals in U.S. and global fisheries,” Conservation Biology, vol. 20, no. 1, pp. 163–169, 2006.
[115]
T. J. O'Shea and R. L. Brownell, “Organochlorine and metal contaminants in baleen whales: a review and evaluation of conservation implications,” Science of the Total Environment, vol. 154, no. 2-3, pp. 179–200, 1994.
[116]
M. Lebeuf, B. Gouteux, L. Measures, and S. Trottier, “Levels and temporal trends (1988-1999) of polybrominated diphenyl ethers in beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary, Canada,” Environmental Science and Technology, vol. 38, no. 11, pp. 2971–2977, 2004.
[117]
P. J. Clapham and R. L. Brownell, “The potential for interspecific competition in baleen whales,” Report of the International Whaling Commission, vol. 46, pp. 361–367, 1996.
[118]
G. Bearzi, S. Agazzi, J. Gonzalvo et al., “Overfishing and the disappearance of short-beaked common dolphins from western Greece,” Endangered Species Research, vol. 5, no. 1, pp. 1–12, 2008.
