ACS Research Committee Report

GENETIC POPULATION STRUCTURE OF MINKES
Source: Andersen, L.W., E.W. Born, R. Dietz, T. Haug, N. Oien, C. Bendixen. Genetic population structure of minke whales Balaenoptera acutorostrata from Greenland, the North East Atlantic and the North Sea probably reflects different ecological regions. Mar Ecol Prog Ser. 2003. 247: 263-280.

Genetic samples of 306 individual minke whales (Balaenoptera acutorostrata) were examined to determine the population structure of minkes in Greenland, Central and Northeast Atlantic and the North Sea. 154 samples were obtained from licensed Greenland and Norwegian whalers from hunts in six areas in the North Atlantic:West Greenland, Jan Mayen, Svalbard, the Barents Sea, Vesteralen/Lofoten, and the North Sea. 30 minkes were sampled in East Greenland and 122 in West Greenland. Samples were collected from different years (1982, 1996-1999) which allowed analysis to determine potential inter-annual variation with a sampling area. The study indicated the existence of 4 genetically differentiated sub-populations: 1) West Greenland, 2) Central North Atlantic-East Greenland-Jan Mayen area, 3) Northeast Atlantic (Svalbard, the Barents Sea and north-western Norway), and 4) North Sea. It is suggested that these sub-populations have been isolated by discontinuities between regions, i.e. each of the sub-populations has evolved in response to regional differences in ecological conditions (oceanography, ice cover, prey type and prey availability).    

BEHAVIORAL RESPONSES OF CAPTIVE COMMON DOLPHINS TO SWIM-WITH PROGRAMS
Source: Kyngdon, D.J., E.O. Minot, K.J. Stafford. Behavioral responses of captive common dolphins Delphinus delphis to a 'Swim-with-Dolphin' program. App Ani Behav Sci 81 (2003):163-170.

Previous studies have examined the behavioral responses of captive bottlenose dolphins (Tursiops truncatus), wild Hector's dolphins (Cephalorhynchus hectori) and wild dusky dolphins (Lagenorhyncus obscurus), to Swim-with-Dolphin Programs (SWD). This study monitored the responses of three captive female common dolphins (Delphinus delphis) to a SWD program. They recorded the use of a refuge area, frequencies and location of surfacings, and behavioral changes before, during and after each SWD session. They found that refuge use increased significantly during the sessions and returned to pre-SWD levels within 15 minutes after the session ended. The dolphins surfaced more often and the percentage of surfacings in the refuge area increased during the SWD sessions. They suggest that the increased use of the refuge area could be an active avoidance of the swimmers by the dolphins, however since the dolphins continued to use the swimmers' end it may be that they are compensating and making room for the increased number of bodies in the pool. Behaviorally, there was little effect of the SWD sessions on general behavior, but there was a decrease in Aggressive, Submissive, Abrupt and Play behaviors and an increase in Touch and Other behaviors. This was contrary to what was expected based on previous studies that showed young, male bottlenose dolphins to increase aggressive and sexual behavior during SWD sessions. The results of this study highlight the need for studies that target the appropriate species, gender, and age of the dolphins, as well as specific history, if possible, to gain a better understanding of behavioral responses.    

VOCAL CLANS OF SPERM WHALES
Source: Rendell, L.E. and H. Whitehead. Vocal clans in sperm whales (Physeter macrocephalus) Proc R Soc Lond B (2003) 270:225-231

Cultural transmission may be a significant source of variation in the behavior of whales and dolphins, especially as regards their vocal signals. This study examines variation in the vocal output of 'codas' by sperm whale social groups. 'Codas' are patterns of clicks used by female sperm whales Physeter macrocephalus. Coda repertoires of known social units in the South Pacific and Caribbean were recorded between 1985-2000. After analysis, that found that the 61 out of 64 known social groups can be reliably allocated into six acoustic 'clans' based on their codas; five in the Pacific and one in the Caribbean. Clans have ranges that span thousands of miles, are sympatric, contain many thousands of whales and most probably result from cultural transmission of vocal patterns. Units seem to form groups preferentially with other units of their own clan. They suggest that this is a rare example of sympatric cultural variation on an oceanic scale. Culture may thus be a more important determinant of sperm whale population structure than genes or geography, a finding that has major implications for our understanding of the species' behavioral and population biology.