Scientific Publication Abstracts

The text of a paper presented by WCNE at a European Cetacean Society Conference in 1992, and published in its proceedings.

Please note: Copies of the full versions of the following articles are not currently available.

Apparent bottom feeding by humpback whales on Stellwagen Bank. Marine Mammal Science 11 (4): 464-479 (October 1995). Hain, J. H. W., S. L. Ellis, R. D. Kenney, P. J. Clapham, B. K. Gray, M. T. Weinrich, and I. G. Babb.

Humpback whales (Megaptera novaeangliae) on Stellwagen Bank off eastern Massachusetts, U.S.A., apparently bottom feed on northern sand lance (Ammodytes dubius). The feeding behavior is characterized by the whales brushing the bottom in depths of less than 40 m, causing sand lance burrowed in the bottom to be flushed up into the water column. The greatest densities of sand lance were in beds of shells and shell debris, termed "shell hash." The brushing against or along the bottom, particularly in these shell hash areas, caused the humpbacks to acquire abrasions and wounding, sometimes rather extensive, of the lateral lower jaw, and lateral and dorso-lateral upper jaw, here termed "jaw scuffing." Scuffing of the dorsal fin and fluke edges was also common and may be at least partially related to this feeding behavior. Both mature and immature, and male and female, humpbacks exhibited jaw scuffing. The bottom-feeding behavior was not exclusive, as jaw-scuffed individuals were also observed to use other feeding behaviors. In recent years (1991-1993), however, bottom feeding appears to have become relatively more common, particularly among young animals. Overall, in the Stellwagen Bank area between 1979 and 1993, a majority of the population engaged in, or had engaged in, bottom feeding and the associated prey flushing.

Behavior and ecology of the Atlantic white-sided dolphin (Lagenorhynchus acutus) in coastal New England waters. Marine Mammal Science 17: 231-248. 2001. Weinrich, M.T., C.R. Belt, and D. Morin.

Atlantic white-sided dolphins (Lagenorhynchus acutus) are among the most abundant, and least studied, cetaceans in coastal New England. Between April and October 1984 through 1997 we sighted 1,231 groups of Atlantic white-sided dolphins, primarily on Stellwagen Bank and Jeffreys Ledge (two shallow glacial deposits along the coasts of Massachusetts, New Hampshire, and Maine). Mean group size was 52 (? 90.9), and was significantly larger from August through October (71.9 ? 111.4) than April through June (35.0 ? 45.4). Calf sightings were uncommon until June and July, after which they were present in over 50% of groups. Combined with observations of apparent newborn calves, this confirms that early summer is an important calving period. The presence of calves did not, however, solely account for the increase in group size. Boat interaction (bow- and stern-wake riding) was the most commonly recorded behavior (47.4% of sightings), followed by traveling (31.4%), interactions with other cetacean species (27.6%), social interaction (15.5%), and feeding (9.5%). While feeding was uncommon, one observation of apparently coordinated "ball" feeding was seen with sand lance (Ammodytes spp.) as the visible prey. Aerial behavior showed a positive correlation with group size, although it was often impossible to tell whether the same dolphins were leaping repeatedly. Eight-eight dolphins were photo-identified using either unusual body pigment or a distinctive dorsal fin. While several individuals were re-identified between years and between areas, no re-identifications were made within a year in the same area. Unusually pigmented individuals were much more likely to be re-identified than those with distinctive dorsal fins, most likely due to higher visibility. We suggest that Atlantic white-sided dolphins are generally using the study area as transients with what appears to be a large home range.

Behavior and Social Organization of Humpback Whale (Megaptera novaeangliae) Mother/Calf Pairs on a North Atlantic Feeding Ground. M.S. Thesis, University of Massachusetts at Dartmouth. 96 pp. 2002. Sardi, K.

Associations of humpback whale (Megaptera novaeangliae) mother/calf pairs in Stellwagen Bank National Marine Sanctuary were examined to define patterns based on associate age and sex class and mother's reproductive history. Mother/calf associations had a bias towards juveniles (whales under five years). In the subset of groups with one associate, the associations of mother/calf pairs with each age class did not differ significantly from random. In contrast, in years when females were not accompanied by a calf, they were observed in association with adults significantly more often. Females in years both when they had a calf and when they did not were observed in association with males more often expected. Males were over represented with both primiparous mothers and with mothers with the highest calving rate (0.5). Males were also over represented with mothers with only one previous calf. Juveniles and intermediates were over represented with primiparous mothers, whereas adults were over represented with mothers with the highest calving rates (0.4 and 0.5). Adults were over represented with mothers with four or more previous calves. Adults were also over represented with mothers that became pregnant in the next breeding season. Associates of mothers that did not become pregnant did not differ significantly from random in age class. The position of the mother, calf and other associates in a group were recorded to determine if the mother places her body between the calf and other whales. During the first observation of each group per day and also during each surfacing of the group, the mother was between the calf and associates significantly more often. She also was in the middle position during a significantly longer portion of the overall observation duration. The relative positions of individuals in the group were not fixed; they were fluid and shifted many times during observations. The surface behavior rate of the calf was analyzed versus whether the calf was associated (within 90m) of the mother or separate (greater than 90m) from her. The aerial behavior, those that create surface disturbance and presumably subsurface noise, rate was significantly higher during separations from the mother. The simple play behavior, those that do not create surface disturbance, rate did not differ significantly depending on the calf's proximity to the mother. However, when the split of mother and calf was witnessed and a before and after rate could be calculated, both aerial and play behavior rates increased after the witnessed split. Both types of behavior also decreased after mother and calf rejoined one another. Aerial behaviors did not begin significantly more often after the witnessed split, whereas play behaviors did. Both behaviors ended significantly more often before a witnessed rejoining of mother and calf.

Behavior of individually-identified sei whales (Balaenoptera borealis) during an episodic influx into the southern Gulf of Maine in 1986. Mark R. Schilling, Irene Seipt, Mason T. Weinrich, Steven E. Frohock, Anne E. Kuhlberg, Phillip J. Clapham

Sei whales (Balaenoptera borealis) are noted for major fluctuations in distribution, often in response to local availability of prey. An influx of sei whales occurred in the southern Gulf of Maine during summer 1986. Forty-seven individuals (including four mothers with calves) were photographically identified using natural markings, including dorsal-fin notches, placement of small circular scars on the animal's flank, and natural variation in dorsal-fin shape and pigment swaths along the dorsal surface behind the blowholes. Seventeen of these whales (36.1%) were photographed on more than one day, and the period between first and last sighting of individuals ranged from one to 66 days. Only six animals were sighted in more than one region in the southern Gulf of Maine. Observed behavior included traveling, nearsurface skim feeding, lunge feeding, and (rarely) "milling" or breaching. Group sizes were small and variable. Two individuals were matched to photographs taken in other regions in or near offshore Gulf of Maine waters. We hypothesize that the southern Gulf of Maine represents a short term feeding sight. The occurrence of individuals without sufficient marks for individual recognition suggests that photoidentification is of limited value in the study of this species.

Behavioral reactions of humpback whales (Megaptera novaeangliae) to biopsy procedures. Fishery Bulletin. Volume 90. Pages 588- 589. 1992. Weinrich, Mason T., Richard H. Lambertsen, Cynthia R. Belt, Mark R. Schilling, Heidi J. Iken, and Stephen E. Syrjala.

Accurate and precise descriptions of behavioral indicators of human activities which disturb cetaceans are required to better control adverse human impacts on these animals. We hypothesize that the application of a technique used to remove a small piece of innervated tissue, a biopsy darting procedure, is likely to result in the display of such behavioral indicators. In order to describe such displays, we recorded behavior of 22 humpback whales (Megaptera novaeangliae) before and after biopsy procedures in the southern Gulf of Maine. Reactions varied considerably among animals. Although respiratory responses were not consistent, biopsied whales generally decreased their ratio of surface to dive time and their net movement rate. Hard tail flicks occurred as an immediate reaction in approximately half the cases. Although 31 behaviors were tested for variation, only hard tail flicks significantly increased in either the number of animals that displayed them or the overall frequency of occurrence during post-biopsy reaction periods. While not statistically significant, some increase was noted in the frequency of trumpet blows and tail slashes, while slow swimming and apparent investigative behavior were noted to decrease. The strongest reactions, observed in two cases, occurred when the dart and retrieval line briefly snagged the whale's flukes. These findings complement and extend other studies on the response of baleen whales to human activity at sea.

Early experience in habitat choice by humpback whales (Megaptera novaeangliae). Journal of Mammalogy 79: 163-170. 1998. Weinrich, M.

The importance of early experience and maternal influence on the return of humpback whales (Megaptera novaeangliae) to traditional feeding grounds has been documented through individual return rates and population genetics. Studies to date, however, have concentrated on large-scale geographic regions (i.e. the Gulf of Maine) and have not compared returns to specific sites within these traditional feeding grounds. Between 1982 and 1990 we sighted 93 humpback mother-offspring pairs in which the calf was re-sighted after weaning. Observations took place at two sites in the southern Gulf of Maine: Stellwagen Bank and Jeffreys Ledge. Return rate to each area was significantly higher if the whale was originally sighted there as a calf (79.4% vs 50.0% on Stellwagen Bank, 71.7% vs 38.8% on Jeffreys Ledge), and no difference was found between male and female offspring. These results indicate that early experience is of prime importance in a humpback whale's subsequent choice of local habitat as well as a regional feeding area.

Evidence for acquisition of a novel feeding behavior: lobtail feeding in humpback whales (Megaptera novaeangliae). Animal Behavior. Volume 44. Pages 1059-1072. 1992. Weinrich, Mason T., Mark R. Schilling & Cynthia R. Belt.

The spread of an apparently normal surface feeding behavior (bubble feeding), which is proceeded by a tail slap, or lobtail (called lobtail feeding), was observed in individually identified humpback whales (Megaptera novaeangliae), feeding on sand lance (Ammodytes americanus), in New England waters during 1980-1989. The proportion of feeding events classified as lobtail feeding was consistent for each individual throughout the entire period that each whale was observed. Ninety- five of the 250 whales observed surface feeding used lobtail feeding. The percentage of animals lobtail feeding increased regularly from 0.0% in 1980 to 50.6% in 1989. Over 50% of whales first seen as calves, and later documented surface feeding, displayed lobtail feeding, although few of their mothers ever employed this behavior. Among animals that were first photographed before 1982 only 12.5% were ever seen lobtail feeding. In contrast, 56.2% of animals first photographed after 1982 used the behavior. No animal was seen to use lobtail feeding before it was 2 years old, although individuals are weaned and separated from their mothers at 1 year. Rudimentary lobtail feeding was witnessed several times among young post- weaning animals. No difference was seen in the frequency of lobtail feeding between sexes. It is hypothesized that this behavior was initiated as whales switched from feeding on herring to sand lance, and has spread through cultural transmission.

Humpback whales (Megaptera novaeangliae) shift their distribution in response to prey in the southern Gulf of Maine. Fishery Bulletin 95: 826-836. 1997. Weinrich, M., M. Martin, R. Griffiths, Jennifer Bove, and M. Schilling.

From the mid-1970's to the mid-80's, Stellwagen Bank was an important humpback whale feeding area with sand lance (Ammodytes spp.) as the major prey. Between 1988 and 1994, however, the number of humpback whales we identified each year on Stellwagen declined from a high of 258 (1990) to seven (1994), and the mean number of whales identified per day from 17.7 (1988) to 0.9 (1994). Adult whales decreased steadily after 1988; juveniles decreased rapidly after 1991. Echo-sounder data from Stellwagen showed that prey trace levels declined from 19.1% of the vertical water column containing prey in 1990 to 2.8% in 1992 (no readings were taken in 1988-1989, or 1993-1994). Simultaneously, the number of whales identified on Jeffreys Ledge, north of Stellwagen Bank, increased dramatically beginning in 1992. Sixty-four percent of the whales identified on Jeffreys in 1992-1994 were seen on Stellwagen Bank in 1988 and 1989. We hypothesize that humpback whales shifted their distribution in order to prey upon recovering herring populations, their primary source of food.

Influence of seasonal migration on geographic distribution of mitochondrial DNA haplotypes in humpback whales. Nature; 344; 238. March 15 1990. Baker, C. S., S. R. Palumbi, R.H Lambertsen, M. T. Weinrich, J. Calambokidis, and S. J. O'Brien.

Humpback whales (Megaptera novaeangliae) migrate nearly 10,000 km each year between summer feeding grounds in temperate of near-polar waters and winter breeding grounds in shallow tropical waters. Observations of marked individuals suggest that a number of distinct seasonal subpopulations which are not separated by obvious geographic barriers. To test whether these observed patterns of distribution and migration are reflected in the genetic structure of populations, we looked for variation in the mitochondrial DNA of 84 individual humpback whales on different feeding and wintering grounds of the North Pacific and western North Atlantic oceans. On the basis of restriction-fragment analysis, we now report a marked segregation of mitochondrial DNA haplotypes among subpopulations as well as between the two oceans. We interpret this segregation to be the consequence of maternally directed fidelity to migratory destinations.

Right Whales (Eubalaena glacialis) on Jeffreys Ledge: An Unrecognized Habitat? Marine Mammal Science: In Press. 1999. Weinrich, M. T., R. D. Kenney, and P. K. Hamilton.

Northern right whales (Eubalaena glacialis) are known to spend the majority of the year between the Great South Channel, southeast of Cape Cod, and the Nova Scotian shelf. We examined sightings of right whales on and around Jeffreys Ledge, a 56-km long glacial deposit off the coast of northern Massachusetts, New Hampshire, and Maine. Sightings were taken from three data sets: 1) a systematic survey of the entire northeastern continental shelf between 1979 and 1982; 2) whale watch and research WCNEise sighting data from 1984-1997; and 3) a collaborative database of sightings collected by organizations doing right whale research and all other available sources. Each database supported a bi-modal sighting peak. During summer (especially July and August) sightings were primarily of mother-calf pairs. Several cow-calf pairs were seen over several days to weeks. Several females were resighted in more than one year, but only when calves were present. During October, November, and December sightings included all age classes, surface feeding behavior was frequently observed, and some animals were resighted over several weeks. Given relatively reduced effort during the fall period, this number of sightings is surprising. During the study, 52 of 374 photo-identified North Atlantic right whales (13.9%) were seen at least once on Jeffreys Ledge. We suggest that Jeffreys Ledge may be a more important right whale habitat than previously believed, and may play an important role in annual m

ovements and distribution of this species.

Short-term association patterns of humpback whale (Megaptera novaeangliae) groups on their feeding grounds in the southern Gulf of Maine. Can. J. Zool. 69: 3005-3011. Weinrich, M. T., and Kuhlberg, A. E. 1991.

Humpback whale (Megaptera novaeangliae) feeding ground associations show a distinct pattern of group size and composition. Median group size was 2 (mean 1.67), and frequency decreased as group size increased. Adult females and juvenile males were observed in pairs significantly more often than singly, whereas adult males and juvenile females were more often alone. Adult female-female pairs occurred significantly more frequently than adult male-male pairs and adult female-juvenile male pairs formed more frequently than adult male-juvenile female pairs. The majority of groups remained associated for at least 10 min; however, as the size of a group increased, so did its tendency to separate within that period. Adult male-male pair associations were of significantly shorter duration than female-female or male-female pair associations. It is hypothesized that adult males may avoid other males on the feeding ground as an extension of breeding competition. The energetic burden of reproduction, and hence the need to forage cooperatively to maximize efficiency, may account for the adult female's social nature. Juveniles of both sexes, less constrained by reproductive costs, exhibit less structured social behavior.

Stable social associations among humpback whales (Megaptera novaeangliae) in the southern Gulf of Maine. Can. J. Zool. 69: 3012 - 3019. Weinrich, M. T.

Stable social associations among humpback whales (Megaptera novaeangliae) were observed from 1980 to 1987 on their feeding grounds in the southern Gulf of Maine. Although most groups were together for only brief periods, two types of stable association were found: 'continuous' (individual whales associated for at least 7 consecutive days; n=30) or 'recurring' (individuals associated at least five times in a 6-week period; n=21). Thirty-seven stable pairs and 3 stable trios involving 56 individual whales were recorded; 1 stable pairs reassociated during more than 1 year. Continuous associations lasted up to 79 days (mean 29,65). Thirty of the 40 associations (75,0%) contained only adults. Females were present in 22 adult associations (73,3%), whereas males were present in only 8 (26,6%). Females sighted with a calf the following year, and therefore pregnant, were members of 6 of the 11 (54,5%) associations that reformed. It is hypothesized that stable associations allow adult females to maximize their net energy gain through cooperative feeding, and may be comprised of closely related animals of individuals with compatible feeding styles.