ACS Research Committee Report

HUMPBACK WHALE WINTERING GROUND HABITAT PREFERENCE
Source: Ersts, P.J. and Rosenbaum, H.C. 2003. Habitat preference reflects social organization of humpback whales (Megaptera novaeangliae) on a wintering ground.

Antongil Bay, on the north-eastern coast of Madagascar, is an important wintering ground for many Indian Ocean humpback whales. Humpback whales use this area typically for mating activities and to give birth to calves. Various social groups in the area were found to utilize different habitats within the bay. Lone mother-calf pairs demonstrated the strongest preference for shallower water (typically less than 20m). Competitive groups, usually involving several males and one female or mother-calf pair, were consistently observed farther away from shore than mother-calf pairs, trios with a mother-calf and another whale, and other trios. There was a correlation between distance from shore and the size of competitive groups, with larger groups being observed farther offshore. There was also a temporal difference in habitat choice for various groups of humpback whales. Observations of humpback whales in the early morning and late afternoon were generally closer to shore, in more shallow water, than observations during midday. These shallow waters were often used for resting behavior. There seemed to be a relationship throughout between behavior, group size, and habitat preference in the Bay..    

EFFECTS OF WHALE WATCHING ON SPERM WHALES
Source: Richter, C.F., Dawson, S.M., and Slooten, E. 2003. Sperm whale watching off Kaikoura, New Zealand: effects of current activities on surfacing and vocalization patterns. Science for Conservation 219. Department of Conservation, Wellington, New Zealand. 78 pp.

Sperm whales (Physeter macrocephalus) are the subject of whale watching efforts in the area of Kaikura, South Island, New Zealand. Whale watching in this area involves year-round boat and aircraft viewing trips. Whale behavior was recorded from boat-based and shore-based observations over four years of the study. It was determined that whale behavior was significantly affected by the presence of whale watching vessels. Blow interval, or time between breaths, decreased in the presence of either whale watching or the research vessel. Whale watching vessels and aircraft led to and increase in the amount of time the whales stayed at the surface, as well as in the number of direction changes. Vessels also led to a decrease in whale vocalizations. There are two "types" of sperm whales observed in this area: residents (stay in area for weeks or months and often return to the area) and transients (seen on one day only). Behavioral changes correlated to the presence of whale watch vessels were more noticeable and more frequent in transient whales, though there was significant variation between individuals.    

POPULATION INCREASE IN NORTH ATLANTIC HUMPBACK WHALES
Source: Stevick, P.T., Allen, J., Clapham, P.J., Friday, N., Katona, S.K., Larsen, F., Lien, J., Mattila, D.K., Palsboll, P.J., Sigurjonsson, J., Smith, T.D., Oien, N., and Hammond, P.S. 2003. North Atlantic humpback whale abundance and rate of increase four decades after protection from whaling. Marine Ecology Progress Series 258: 263-273.

The population of humpback whales (Megaptera novaeangliae) in the North Atlantic was severely depleted due to whaling efforts. This species has been legally protected from exploitation since 1955. Most likely, there has been some recovery in the population numbers, but previously there has not been enough information to make accurate estimates. This study involves photo-identification of the distinctive patterns on the underside of the tails of humpback whales. Many photographs were taken over a 14 year period and a wide geographic range; they were compared to each other to remove any duplicate sightings of the same individuals and to determine potential movements of whales. Statistical techniques were used to more accurately estimate population size. Using this technique, the most precise estimate for the West Indies population was calculated as 10,752. The average rate of increase for this population over a 14 year period was estimated at 0.031. Most humpback whales in the North Atlantic share a breeding/wintering ground in the West Indies, but there are several distinct feeding/summering grounds in colder, more northern waters. Therefore, estimates for the entire North Atlantic humpback whale population can be extrapolated using the estimate for West Indies breeding population. Using all available data, the North Atlantic population was estimated at 11,570.   

TWO TYPES OF BLUE WHALE CALLS FOUND IN THE GULF OF ALASKA
Source: Stafford, K.M. 2003. Two types of blue whale calls were recorded in the Gulf of Alaska. Marine Mammal Science 19 (4): 682-693.

Blue whales (Balaenoptera musculus) were, at one time, found throughout the Gulf of Alaska. However, none have been observed in this area since they were the subject of whaling efforts. A hydrophone array was deployed in October 1999 to record whale sounds. Calls were identified in the recordings that were attributed to both northeastern and northwestern Pacific blue whales. Both call types were recorded from October through December of 1999, and also July through December of 2000. Both calls were recorded on the same hydrophone at the same times, indicating a temporal and, perhaps, spatial overlap of the animals producing the calls. The results indicate that perhaps both populations of blue whales utilize the Gulf of Alaska.    

MOTHER-CALF ASSOCIATION PATTERNS IN BOTTLENOSE DOLPHINS
Source: Grellier, K., Hammond, P.S., Wilson, B., Sanders-Reed, C.A., and Thompson, P.M. 2003. Use of photo-identification data to quantify mother-calf association patterns in bottlenose dolphins. Canadian Journal of Zoology 81 (9): 1421-1427.

Bottlenose dolphins (Tursiops truncatus) live in a fission-fusion society, meaning that they change associations regularly. In this type of society, the mother-calf bond is long and often extends beyond weaning. In this study, mother-calf associations were quantified using photo-identification of individuals off of eastern Scotland. Association indices were used to quantify association patterns. Using this technique, 17 adults were assigned as mothers to 20 young calves. The association index for mothers and calves remained high until at least the 8th year of the calf's life. Although still in the same pod, calves surfaced beside their mothers less often as they grew older.

2003 NORTH ATLANTIC RIGHT WHALE CONSORTIUM MEETING
The North Atlantic Right Whale Consortium is a group of North Atlantic right whale researchers. The Consortium meets once a year to discuss ongoing research projects and developments in conservation, such as shifting of shipping lanes and fishing gear modifications. The following summaries are only a few interesting findings presented during the 2003 meeting.

POPULATION UPDATE
Pike, B. 2003. The North Atlantic right whale catalog: an update on mortality, reproduction, and population status.

There are 328 right whales listed as "alive", 99 listed as "presumed dead" (due to lack of sightings), and 16 known dead in the catalog. The 328 live right whales include 102 adult females, 122 adult males, 25 juvenile females, and 26 juvenile males. There is an average of 65-75% of the population that is resighted every year. The average age of first time moms was 11 years, which has increased since the previous estimate of 9.5 years in 2001. There were at least 19 new mothers in 2003, six of those were first time mothers. The average calving interval was determined to be 5.8 years, which again increased from the previous report of approximately three years.

MOVEMENTS OF RIGHT WHALES FROM THE BAY OF FUNDY
Source: Baumgartner, M. and Mate, B. 2003. North Atlantic right whale habitat inferred from satellite telemetry.

Right whales were satellite tagged in the Bay of Fundy, where they spend the summer. The satellite tracks of the tagged animals went to Jeffreys Ledge, Roseway Basin, and the Great South Channel. Whales more often went to areas with cold bottom water and low surface salinity, such as Jeffreys Ledge and the Roseway Basin, than would be seen by random. Unexpectedly, whales did not often frequent deep basins such as the Gulf of Maine and the Scotian Shelf, where copepods (their typical prey) are abundant.

GENETICS
Source: Frasier, T.R., Bower, R., Brown, M.W., Kraus, S.D., and White, B.N. 2003. Genetic profiling of North Atlantic right whales: application to paternity analysis.

Genetic samples from 294 known and 75 unknown whales, including 97 mother/calf pairs and approximately 60% of potential fathers per year, were analyzed. There were 21 calves with known paternity; a total of 68% of calves were fathered by unsampled males. Two males sired multiple offspring- one sired four calves and one sired three calves. Genetic evidence indicates that there are more reproductive females and males than what is photo-identified. An analysis was conducted on whether males and females that were known parents of the same calf were seen within one month of one another in the same habitat. In only two cases the mother and father were observed in the same habitat within a month: one was seen in the Bay of Fundy and one in Massachusetts Bay. This result indicates that mating probably does not occur in these northern habitats, as has been suggested previously.