Weinrich et al : Behavior of Megaptera novaeangliae during biopsy 



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whales. To obtain the tissue samples for this project, 

 a projectile biopsy dart was used (Lambertsen 1987, 

 Lambertsen and Duf field 1987, Lambertsen et al. 

 1988). 



In an attempt to better understand the disturbance 

 response of large whales, the present study was under- 

 taken to assess the behavioral reaction of humpback 

 whales to the biopsy procedures previously described 

 (Lambertsen 1987). We reason that since the biopsy 

 dart removes a small piece of innervated tissue, it is 

 likely to be perceived by the whale as a noxious stim- 

 ulus and should cause some observable response. Our 

 results compare the behaviors of the whales before and 

 after exposure to this relatively short-term, moderate- 

 level stressful stimulus. 



Materials and methods 



Cruises to collect biopsy samples took place each year 

 from 1983 to 1985 on Jeffrey's Ledge or Stellwagen 

 Bank in the Gulf of Maine. In 1983 and 1984 various 

 types of small power vessels (< 12.8 m) were used, in- 

 cluding an 11.6m sportfishing vessel equipped with one 

 Detroit Diesel 671 engine, and a 12.8m pilot boat with 

 two Detroit Diesel 671 engines. In 1985, a 6.1m run- 

 about with a 175hp outboard engine and an 11m sail- 

 ing sloop were used simultaneously. The use of two 

 vessels allowed one (the 6.1 m runabout) to be dedicated 

 to collection of behavioral data in the methodology 

 described below. The immediate response of whales to 

 biopsy darting was recorded on two days in 1983, two 

 in 1984, and six in 1985. 



The biopsy apparatus used in this study consisted of 

 a tethered retrievable biopsy dart, aimed at the flank 

 below the dorsal fin, fired from a 68 kg crossbow 

 (Lambertsen 1987). A small biopsy punch fitted with 

 internal prongs and attached to the tip of the dart shaft 

 removed the tissue from the animal. A small tissue 

 sample, including both epidermis and dermis, was thus 

 obtained by a cutting action on penetration, and tear- 

 ing on rebound. Upon penetration of the dart into the 

 whale, a rebound was forced by a 2.5cm diameter 

 flange set 2 cm back from the tip of the biopsy punch. 

 In the first 2 years of the study, emphasis was placed 

 on collecting as many biopsies as possible during brief 

 periods at sea. Behavioral observations were collected 

 opportunistically to provide qualitatively classified data 

 on immediate reactions. For comparative purposes, 

 these observations were ranked in a manner similar to 

 that used by Mathews (1986), who studied the reactions 

 of eight gray whales Eschrichtius robustus to a similar 

 biopsy procedure. Categories used in this initial anal- 

 ysis included: 



No reaction The whale continued its prebiopsy be- 

 havior with no detectable change. 



Low-level reaction The animal modified its behavior, 

 but displayed none of the overtly forceful behaviors 

 listed as moderate or strong reactions (e.g., imme- 

 diate dive). 

 Moderate reaction The animal modified its behavior 

 in a more forceful manner (trumpet blows, hard tail 

 flicks), but gave no prolonged evidence of behavioral 

 disturbance. 

 Strong reaction The animal modified its behavior to 

 a succession of forceful activities (continuous surges, 

 tail slashes, numerous trumpet blows). 

 To test statistical differences in reaction levels among 

 age-classes, non- and low-level reaction frequencies 

 were combined, as were moderate and strong reac- 

 tions. This was necessitated by the low expected values 

 of the frequencies in a chi-square table based on the 

 data in Table 1. 



All data from 1983-85 were used to categorize im- 

 mediate response levels; in 1985, a 30-min prebiopsy 

 control period and a 30-min postbiopsy response 

 period were defined to standardize a paired data set 

 of respiratory and other surface behaviors. This ap- 

 proach used the vessel dedicated to behavioral data col- 

 lection to institute a focal sampling technique (Altmann 

 1974) to allow quantitative comparison of the pre- and 

 postbiopsy focal periods as "paired samples." Upon 

 sighting a group of whales, each individual was dis- 

 tinguished through 7 X 50 binoculars using distinctive 

 natural markings on the dorsal fin or the ventral sur- 

 face of the tail flukes (Katona and Whitehead 1981). 

 Because of the necessity of identifying individual 

 respirations and behaviors within the group, dorsal 

 fin shape was used whenever possible during focal 

 samples; permanent identification came from fluke 

 photographs taken during the approach for the biopsy 

 strike. Once individuals were distinguished from one 

 another, a 30-min "control" (i.e., pretreatment) focal 

 sample was then initiated. During this period the 

 engines of the observation vessel were shut down to 

 eliminate engine noise. No approaches closer than 

 100 m were made prior to the onset of, or during, the 

 30-min control period. If the whale moved farther than 

 1000m from the research vessel, making data collec- 

 tion difficult, the engine was started and approach was 

 made slowly to within ~300m of the whale. At the con- 

 clusion of the 30-min "control" focal sample the whale 

 was then approached at close range (3-40 m) for the 

 biopsy attempt. The same protocol was followed after 

 the biopsy for a comparable "experimental" (i.e., post- 

 treatment) data set, which started at the moment of 

 impact by the dart. 



During focal samples, data were collected on four 

 respiratory variables: (1) number of respirations 

 ("blows") during a given surface interval, (2) time 

 between each respiration ("blow interval"), (3) time 



