ACS Research Committee Report

FATTY ACIDS IN MINKE WHALE BLUBBER
Source: Olsen, E. and O. Grahl-Nielsen. 2003. Blubber fatty acids of minke whales: stratification, population identification and relation to diet. Marine Biology 142: 13-24.

Blubber samples taken from minke whales in the Norwegian Sea and the North Sea were analyzed for fatty acid composition. Previously, fatty acids have been used to identify different populations or "stocks" of whales, as well as to determine differences in whale diet. This study found a difference in fatty acid composition between the inner and outer blubber layer. The inner blubber is mostly a storage area for short-term energy; the fatty acids in this inner layer are deposited from recent diet, in this case, herring and sand eels. However, these fatty acids are notably different than those found directly in the prey species, indicating that the whale must change the structure of the acids during metabolism. The outer blubber insulates the whale from the cold surrounding water, and makes it buoyant and streamlined. Fatty acids in the outer blubber are even more distinct from those in prey species; most likely these compounds are changed when they are transferred from the inner to the outer blubber layer. Therefore, it would be nearly impossible to determine a whale's diet based solely on outer blubber samples. There was a significant difference in fatty acid composition in both the outer and the inner blubber layer between the two geographic regions in this study, indicating that either layer could be used to define different populations of minke whales.    

ORGANOCHLORINE PESTICIDES IN THE BLUBBER OF ST. LAWRENCE BELUGAS
Source: Hobbs, Karen E., Derek C. G. Muir, Robert Michaud, Pierre Beland, Robert J. Letcher, and Ross J. Norstrom. 2003. PCBs and organochlorine pesticides in blubber biopsies from free-ranging St. Lawrence River Estuary beluga whales. Environmental Pollution 122: 291-302.

Blubber biopsies were taken of 44 (34 male and 10 female) free-swimming beluga whales in the St. Lawrence River Estuary between 1994 and 1998. Contaminant levels were higher overall in males than in females. This result has been found previously with other contaminated marine mammal populations, most likely because females rid themselves of some toxins by transferring them to their offspring during gestation and lactation. Visual estimation of the size of biopsied whales suggested that younger adult males had lower concentrations of most organochlorine toxins than older males. Due to small sample size, the same analysis was not possible for females. The most common contaminant found were PCBs (polychlorinated biphenyls). Biopsy samples were compared against samples taken from 15 (8 male and 7 female) stranded beluga whales; biopsied whales had lower concentrations of most contaminants than stranded animals. This difference may be due to a difference in dietary preferences. Some belugas may feed on fish, such as eels migrating from Lake Ontario, that are higher in contaminant load.    

ALLIANCE FORMATION IN BOTTLENOSE DOLPHINS - AUSTRALIA
Source: Krutzen, Michael, William B. Sherwin, Richard C. Connor, Lynne M. Barre, Tom Van de Casteele, Janet Mann, and Robert Brooks. 2003. Contrasting relatedness patterns in bottlenose dolphins (Tursiops sp.) with different alliance strategies. Proc. R. Soc. Lond. 270: 497-502.

Male bottlenose dolphins in Shark Bay, Australia, seem to have two distinct mating strategies involving alliance formation. The first strategy involves stable "first-order" alliances between pairs or trios of male dolphins in order to herd reproductive females. Then, two first-order alliances transiently join together to form a "second-order" alliance to compete against other male alliances by guarding or even stealing females. Alternatively, males may change the composition of their first-order alliances within a larger (up to 14 individuals) second-order alliance (called a "super-alliance"), demonstrating partner preferences and avoidances. Males in stable first-order and second-order alliances are significantly more related to each other than would be expected by random chance. Males in these alliances can gain inclusive fitness benefits by assisting a relative to potentially mate and produce offspring. However, super-alliance members are not significantly more related to each other than to any other male in the population. Super-alliance members do not receive benefits to their inclusive fitness by allying with other members, but the size of the alliance may increase their ability to compete in different situations.    

GRAY WHALE DISTRIBUTION IN THE BERING SEA
Source: Moore, Sue E., Jacqueline M. Grebmeier, and Jeremy R. Davies. 2003. Gray whale distribution relative to forage habitat in the northern Bering Sea: current conditions and retrospective summary. Can. J. Zool. 81(4): 734-742.

Between 1999 and 2000, hundreds of gray whales stranded along the west coast of North America, from Mexico to Alaska. The cause of these strandings is unknown, but the most likely explanation is starvation due to a reduction in available prey, especially in the Chirikov Basin in the Bering Sea. Throughout the 1980s, the Chirikov Basin was an important feeding area for gray whales, but since that time there has not been an assessment of gray whale or amphipod prey distribution or abundance. A 5-day research cruise was conducted in 2002 and found up to a 17-fold decline in gray whale sightings in the Chirikov Basin. During the 1980s, gray whale sightings in the Chirikov Basin were variable and were highest where ampeliscid amphipods were the dominant bottom prey. There has been a decrease in amphipod concentrations from 1984 to 2000, when gray whale populations increased, potentially leading to the strandings.    

SPERM WHALE BEHAVIOR DURING EXPOSURE TO SEISMIC SURVEY PULSES
Source: Madsen, P. T., B. Mohl, B. K. Nielsen, and M. Wahlberg. 2002. Male sperm whale behavior during exposures to distant seismic survey pulses. Aquatic mammals 28(3): 231-240.

The behavior of male sperm whales was recorded during exposure to pulses from a remote seismic survey vessel. Five hours of acoustic recordings included air gun pulses and sperm whale clicks. Exposure to the survey pulses did not cause an observable avoidance response by sperm whales in the area. In addition, whales did not stop or significantly alter their vocalizations during foraging.