Sighting rates and prey of Minke Whales (Balaenoptera acutorostrata) and other cetaceans off Cormorant Island, British Columbia

Abstract

From June to August 2012, we conducted over 500 h of visual surveys from Cormorant Island, British Columbia, to determine behaviour and habitat use patterns of nearby cetaceans. Seven species were documented, but Minke Whales (Balaenoptera acutorostrata) were by far the most common and were observed lunge feeding at the surface on 15 occasions. In addition, this species was documented surface lunge feeding on Pacific Herring (Clupea pallasi) and Pacific Sand Lance (Ammodytes personatus) on 32 occasions during vessel-based cetacean surveys around Cormorant Island between 2010 and 2014. Although Minke Whales are relatively uncommon in British Columbia, these results indicate that they can regularly be found in specific feeding areas during the summer.

Full text

Sighting rates and prey of Minke Whales (Balaenoptera
acutorostrata

  
*1and3
1Marine Education a nd Research Society, P.O. Box 1347, Port McNeill, British Columbia V0N 2R0 Canada
2Bay Cetology, P.O. Box 554, Alert Bay, British Columbia V0N 1A0 Canada
3Hakai Institute, P.O. Box 309, Heriot Bay, British Columbia V0P 1H0 Canada
*Correspondi ng author: jrtowers@gmail.com
Towers, J.R., C.J. McMillan, and R.S. Piercey. 2019. Sighting rates and prey of Min ke Whales (Balaenoptera acutorostrata)
  
     

                        
          
(Balaenoptera acutorostrata      
  Clupea pallasi  
Lance (Ammodytes personatus     
 
    
Key words: Min ke Whale; Balaenoptera acutorostrata Clupea pallasi
Sand Lance; Ammodytes personatus; Cormora nt Island; British Columbia
     
            
  
 
   
 
for depleted populations of Killer Whale (Orcinus
orca), Humpback Whale (Megaptera novaeangliae),
   Balaenoptera physalus), and some
      
ingly abundant and widespread in coastal waters in
   et al. 2009, 2013, 2017; Nichol et
al. 2018; Towers et al. 2015, 2018, 2019). Although the
  

ecology and habitat use patterns of some, such as
Minke W hale (Balaenoptera acutorostrata), remain
poorly understood.
Minke Whale is a small, migrator y baleen whale
that normally occurs in coastal waters of the eastern
  et al.
2013). Despite a lack of human exploitation history in
    

     
documented Minke W hales 18 times between 1991 and
         
north, in the coastal waters of British Columbia, sur

  et al. (2010) detected only a combined total of

       
Whales in British Columbia and Washington has also
      
         
(Dorsey et al. 1990) and 44 between 2005 and 2012
(Towers et al.     
not been compared between these periods, but at least

       
 
          
  
sey et al. 1990; Towers et al. 2013).

144
  
Note

2019  et al. 
          

        
           
Herr ing (Clupea pallasi    
(Ammodytes personatus) on 10 and two occasions,
et al.
      
       
          
et al. 2013).
 
shallow compared to depths of other nearby water
   
    
bathymetry in this area result in strong currents (<10

            



           

     
    
       
Island in the summer of 2012 while making concur
rent under water acoustic recordings. This note pre
      

that were opportunistically documented from small

to 2014. The acoustic results of this study are reported
in Nikolich and Towers (2018).
 
the north shore of Cormorant Island at 50°
°
and 15 × 80 binoculars (Steiner, Greely, Colorado,
USA) with built in magnetic (M) compass and ret
        
           °
(272° ° 
 
         
__Sho re
watch_Seastate.pdf for explanation of Beaufort sea
     
   Balaenoptera acutorostrata) predation

of British Colu mbia.

   Vol . 133
states). Data, including Beaufort sea state, tide height,
 
       
and reticle distance were recorded each time a cet
acean surfaced (Nikolich and Towers 2018), but when
Minke W hales and other species were present in the

  
 
         
     
       
scribed and shown in Towers (2011). To reduce any
biases arising from animals being missed when sight

area, cetacean occurrence is portrayed in this paper
           
   
  
   

    

             
   
    
aceans were documented: Minke Whale, Humpback
      Orcinus
orca; also known as West Coast Transient popula
Phocoenoides dalli), Harbour
Porpoise (Phocoena phocoena    
sided Dolphin (Lagenorhynchus obliquidens 
2). Minke Whales had the highest PPUE (0.44), as

        
     
   
Towers 2011). Harbour Porpoises were the second
most commonly present species in the study area fol
      
 
 
documented transiting; although most species likely
foraged at depth in the study area, only Minke Whales,
0
2
4
6
8
10
12
Date
Units of survey effort
15−Jun 30−Jun 15−Jul 30−Jul 15−Aug
Effort
MW HP
DP HW
PWSD BKW
FW
   
Island, Br itish Columbia, 11 June to 15 August 2012.
MW HP HW DP PWSD BKW 
  45 39 14 20 5 4 1
Sightings 1551 109 113 35 23 40 3
Units present 224 80 27 23 8 8 2
PPUE 0.44   0.05 0.04 0.02 0.02 0
                   O rcinus orca            Phocoenoides dalli           Balaenoptera
physalusPhocoena phocoenaMegaptera novaeangliae  
Minke W hale (Balaenoptera acutorostrataLagenorhynchus obliquidens).
  
 
   
Balaenoptera acuto-
rostrataPhocoena phocoena),
Megaptera novaeangliae), DP
Phocoenoides dalli
 Lagenorhynchus obliquidens), BKW
Orcinus orca 
(Balaenoptera physalus).
        

   
occasion, and Minke and Humpback Whales were
    
            

any species was detected.
Between 10 September 2010 and 7 August 2014,
                 
morant Island was also opportunistically documented
      
        
        

                

 



2019  et al. 
Of the other species documented in this study, all
    
et al.   
chol et al. 2013; McMillan et al. 2018; Towers et al.
2018). Among them, at least the second, third, and


   et al.
1998; Nichol et al.
search Society unpubl. data). All species documented
       
          

         
  Min ke Whale (Balaenoptera acutorostrata Clupea p alla si) o n 18
Ammodytes personatus) on 11 June 2014. Photos: Jared Towers.

148   Vol . 133
         Balaenoptera acutorostrata) around Cormorant Island,
Clupea pallasi
(Ammodytes personatus).
Date  Prey species
10 Se p. 2010 M004 
10 Se p. 2010  
18 Jul. 2011 M0 01  
27 Jul. 2011   
1 Aug. 2011 M022  
18 Sep. 2011 M007 
18 Sep. 2011 M007 
15 Jul. 2012 M0 01 
15 Jul. 2012 M004  
15 Jul. 2012 M0 01 
15 Jul. 2012 M002 
 M001 
 M004 
18 Jul. 2012 M004  
18 Jul. 2012 M004  
18 Jul. 2012 M004 
Date  Prey species
18 Jul. 2012 M004 
20 Jul. 2012 M022  
25 Jul. 2012 M0 01  
    
17 Jun. 2013 M0 01  
17 Jun. 2013 M0 01  
17 Jun. 2013 M0 01  
17 Jun. 2013 M0 01  
11 Sep. 2013 M001 
11 Jun. 2014 M0 01 
11 Jun. 2014 M0 01 
14 Jun . 2 014   
1 Jul. 2014 M022  
1 Jul. 2014 M022  
31 Jul. 2014   
7 Aug. 2014 M0 01  

et al. (2 018).
        
         

ings compared with other cetacean species and numer

     


 
documented such high rates of Minke Whale occur



        
Minke W hales and their prey are not unlike those
documented in Minke Whale habitat in other regions.
                 
shallow water that is near deeper water in Washington
  et al. 1989) and Scotland (Robinson et al.
2009). The dynamic bottom topography of such areas
          
      et al. 20 05;
Tynan et al.
substrate around Cor morant Island and in other areas
where Minke Whales are often found in the west
ern and eastern North Atlantic (Naud et al. 2 003;
MacLeod et al. 2004; Robinson et al. 2009; de Boer
   

 et al.
     
 
    
tuations in the abundance and distribution of their


   
        

 


This research was funded in part by Mountain

     
  

bert and Wendy Thompson for supplying some ma

for input toward study design, and George Speck for
 
Nation land.

  2010. Cetacea n abundance in the Califor nia current

  
    
 
fornia, USA.
  and     2007. Abundance and popula
tion densit y of cetaceans in the California current eco


  and    
         
Ammodytes personatus
         

2019  et al. 
            
             
to whales: trophic lin ks in a coastal upwelling system.
     

              
ke whale Balaenoptera acutorostrata 
        

08598
 and 
1990. Minke whale (Balaenoptera acutorostrata) from


Whaling Commission 
2014. Marine Mammals of British Columbia.
Royal BC Museum , Victoria, Brit ish Columbia, Can ada.
     
   and  
        

            
          
Columbia, Canada.
            
   
   2017. Habitats of special im
portance to resident Killer Whales (Orcinus orca   
       
        
Oceans Canada, Ottawa , Ontar io, Canada.
      
 and  2009. An
    
           
                 
eries and Oceans Canada, Ottawa, On tario, Canada.
 and 
 
of critical habitat for transient Killer Whales (Orcinus
orca           
            
eries and Oceans Ca nada, O ttawa, Ontario, Canada.
    and     

          
Biological Stat ion, Nanaimo, Brit ish Columbia, Cana da.
      and  1989. The for
  
    
     
            
 and 2004.
Seasonal distribution of min ke whales Balaenoptera
acu torostrata                               
Isle of Mull, Scotland. Marine Ecology P rogress Series

        2018.
 
humpback whale foraging strateg y. Marine Mammal
           
                                           
    Lagenorhyncus obli-
quidens   
        
             
    and 

phology on minke whale (Balaenoptera acutorostrata)
distr ibution in t he Mingan Island (Canada). Journal of
   
  
  
      
      2018. Distribution,
     
(Balaenoptera physalus    

  
Ontario, Canada.
           
 and  
lap and niche partit ioning of sympatric harbor por
   
         
 
     
common minke whales (Balaenoptera acutorostrata) in
 
   
 and 
2009. The dist ribution and habitat preference of coast
ally occu rring minke whales (Balaenoptera acutoro-
strata       
         

     
 
 
bia, Cana da.
  and     
    
dent Killer Whale population in 2014. Canadian tech
         
                           
  
 and  
(Balaenoptera physalus   
continental North America. Northwestern Nat uralist 99:
        
  
        
          
          
          

 
                 
      
      
  
ters of Brit ish Columbia, Canada. Canadian technical

150  Vol. 133
     
and Oceans Canad a, Ott awa, Onta rio, Cana da.
  
 and   2005. Cetacean distributions
           
      

       
                 
Phocoena phocoena      Pho coe-
noides dalli, in the i nland waters of Brit ish Co lu m bia a nd
in Mar ine Mam mal Protection
     
 

  and   2007. Distribution and
abunda nce of mari ne mammals in the coastal wa
ters of Brit ish Columbia, Canada. Journal of Cetacea n

R
Accepted 17 January 2019