GASKIN and WATSON: HARBOR I'ORF'OISE 



Table 2.— Results of categorical data procedure tests for 

 observed numbers of fiarbor porpoises In comparison to ex- 

 pected numbers withi different environmental parameters In 

 thie FIsfi Harbour region of souttiern New Brunswick, 

 1972-75. 1. FIsfi Harbour -(- Lords Cove (see Figure 1). n = 

 observation periods; x^ = two-way table statistic. 



Parameter 

 measured 



n 



df 



Years (1972-75) 

 Time of year' 



(July to early September) 

 Time of day^ 



(0600- -I- 1900) 

 Tidal amplitude' 

 Tidal pfiases" 



(Start of falling tide to 



end of rising tide) 

 Lunar phiase* 



(New moon to full moon) 

 Wind extant^ 



(On sfiore, coastwise, or 



offshore) 

 Wind 24 ti previous^ 



249 



249 



249 

 249 



249 



3 



2 



4 

 3 



39.57 0.0001* 



63.69 0.0001 • 



3.67 0.4520 



7.80 0.0500* 



3.31 0.8450 



249 3 5.38 0.1450 



249 2 17.58 0.003 

 249 2 12.22 0.0094 



'Categorical division of ttiree periods (July, first 3 wk of 

 August, last 1 V2 wk of August -1- early September) to balance 

 effort. 



^Four periods of 3 h eacti, post-1900 observations amal- 

 gamated. 



^Four subpfiases (> 5.5, 5.6-6.5. 6.6-7.5, ^ 7.6 m). 



'Thie eigfit subptiases given In Figure 4 were used. 



^Three subdivisions used. More subdivision tfian thiese 

 resulted in many empty data cells. 



^Four subdivisions used. More subdivision tfian tfiese 

 resulted In many empty data cells. 



*Statistically significant at 0.05 level or better. 



Table 3.— Results of categorical data procedure tests for 

 observed numbers of harbor porpoises in comparison to ex- 

 pected numbers with different environmental parameters In 

 the Fish Harbour region of southern New Brunswick, 

 1972-75. 11. Simpson's Passage, n ~ observation periods; 

 X^ - two-way table statistic. 



Parameter 

 measured 



n 



df 



Years (1972-75) 

 Time of year' 



(July to early September) 

 Time of day^ 



(1600- -I- 1900) 

 Tidal amplitude' 

 Tidal phases" 



(Start of falling tide to 



end of rising tide) 

 Lunar phase* 



(New moon to full moon) 

 Wind extant^ 



(Onshore, coastwise or 



offshore) 

 Wind 24 h previous^ 



132 



132 



132 

 132 



132 



3 



2 



4 

 3 



7.58 0.050* 



16.99 0.0002* 



5.98 0.201 



2.54 0.468 



9.97 0.190 



132 3 7.38 0.061* 



132 2 0.95 0.620 



132 2 0.93 0.628 



'Categorical division of three periods (July, first 3 wk of 

 August, last 1 V2 wk of August -1- early September) to balance 

 effort. 



^Four periods of 3 h each, post-1900 observations amal- 

 gamated. 



'Four subphase (> 5.5, 5.6-6.5, 6.6-7.5, > 7.6 m). 



"The eight subphases given in Figure 4 were used. 



^Three subdivisions used. More subdivision than these 

 resulted in many empty data cells. 



*Four subdivision used. More subdivision that these 

 resulted In many empty data cells. 



'Statistically significant. 

 **Close to significance at 0.05 level. 



magnitude of tidal amplitude in Simpson's Passage. 

 In shallower, semi-enclosed Fish Harbour however, 

 significantly more porpoises were present (P = 0.05) 

 at low tidal amplitudes (< 6.5 m) than high 

 amplitudes (^ 6.6 m). Data for the most commonly 

 sighted individual (a female with a large dorsal scar) 

 corroborated this general finding; about 78% of all 

 sightings of this animals were made when the ampli- 

 tude was 6.5 m or less. 



Relative abundance did not alter (P = 0.84, 0.19) 

 in either zone of the study area during the tidal cycle. 

 Similarly no significant change occurred relative to 

 the lunar phase in Fish Harbour, although in Simp- 

 son's Passage the x^ value approached the arbitrary 

 0.05 level of significance (P = 0.061; n = 249). No 

 relationship between extant or previous wind direc- 

 tion was evident in Simpson's Passage {P = 0.62, 

 0.63; n = 132), but there appeared to be a significant 

 association between wind direction and relative 

 abundance of porpoises in Fish Harbour (P = 

 0.0003, 0.009; n = 249). In both cases far more 

 animals were present during onshore wind directions 

 than when winds were coastwise or offshore. 



Distribution and movements of porpoises on the 

 fine scale is likely to be correlated with the presence 



or absence of food species which, in the Quoddy 

 region, consist largely of juvenile herring, Clupea 

 harengiis; mackerel; and small gadoids (Smith and 

 Gaskin 1974). The dispersal of the former in this 

 region is greatly influenced by current velocities 

 (Jovellanos and Gaskin 1983). Unfortunately the 

 beam width of available equipment was far too nar- 

 row to permit us to cover the study area by acoustic 

 survey thoroughly, or even representatively, at any 

 given time or tide phase. Because one of our major 

 aims at the outset of the study was to avoid disturb- 

 ing normal behavior of the porpoises, it was also 

 rarely possible to acoustically scan in their immedi- 

 ate vicinity. We were however able to infer feeding 

 behavior from diving patterns (e.g., "pattern B") car- 

 ried out consistently in one location (Watson and 

 Gaskin 1983). Sometimes fish were seen jumping at 

 the surface in such areas (Fig. 3), and these zones 

 were acoustically scanned on an opportunistic basis. 

 Fish schools, recorded during bottom topographic 

 acoustic mapping runs, tended to be concentrated at 

 several locations in which porpoises were often 

 sighted. Usually these traces were of herring school- 

 type. While this species predominates in the Quoddy 

 region in the summer months (Jovellanos and Gaskin 



433 



