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Estimates of current population size, known as abundance estimates, are derived from a combination of fieldwork and computer modelling.  Vessel-based and aerial sighting surveys, acoustic monitoring, and analysis of individual animal markings are techniques used independently or in conjunction with each other to count whales.  The information gathered from this fieldwork is used as the basis for population modelling which produces an abundance estimate.  

In 2017, the IWC Scientific Committee established a new expert group to review and agree all the Abundance Estimates submitted to the Scientific Committee.  This new process ensures quality and consistency across all the estimates used by the IWC. 

Click here to read more about the establishment and work of the Scientific Committee’s Working Group on Abundance Estimates (ASI). 

It is impossible for cetacean abundance estimates to be completely precise and IWC estimates are presented as a ‘best estimate’ figure, accompanied by a 95% Confidence Interval, showing a range of plausible values for the population's actual abundance.  As an example, the table below shows that the 1991/92-2003/4 abundance estimate for Southern Hemisphere blue whales is 2,300 with a 95% confidence interval of 1,150-4,500. This means that the range 1,150-4,500 was computed using a method that has a 95% chance of including the population's actual abundance.

Increases or decreases in population are indicated within the table, where these have been identified.

At present the IWC has agreed estimates only for some species/areas.  With the establishment of the ASI group it is planned to update this table and fill in the gaps where possible.

The IWC’s most recent Abundance Estimates


MINKE WHALES

 

Year(s) to which estimate applies               estimate Approximate 95% CI

Southern Hemisphere

1985/86-1990/91

720,000

510,000 – 1,010,000

 

1991/92-2003/04

515,000

360,000  –   730,000

North Atlantic

 

 

 

- Northeast & Central

2014-2019

150,000

112,000 –201,000

- Northeast

1989

65,000

44,000 – 95,000

 

1995

112,000

91,000 – 138,000

 

1996-2000

80,000

59,000 – 108,000

 

2003-2007

81,000

 51,000 – 128,000

 

2008-2013

90,000

62,000 – 128,000

 

2014-2019

104,700

75,200 –145,750

- Central

2005-2007

50,000

30,000 – 83,000

 

2015-2016

64,000

43,000 –93,000

- West Greenland

2007

  9,100

4,300 – 19,000

 

2015

  5,100

2,100 – 12,000

North Pacific

     

- North West Pacific and Okhotsk Sea

1990-91

28,000

17,000 – 45,000

 

2003

 20,000

13,000 – 30,000

- Sea of Japan

2004-2006

4,200

2,700 – 6,300

 



BLUE WHALES

  Year(s) to which estimate applies Approximate point estimate Approximate 95% CI

Southern Hemisphere

(excluding pygmy blue)

 1978/79-1983/84 450
200 – 1,000
 
1985/86-1990/91
560
200 – 1,400

 

1991/92-2003/04
2,300
1,150 – 4,500
The estimated rate of increase of Southern Hemisphere Blue whales is 8.2% (95% confidence interval 3.8-12.5%) per year between 1978/79 and 2003/04

North Pacific

 
 
 

- Eastern

2008
2,500
1,700 – 3,600

 



FIN WHALES

 

Year(s) to which estimate applies

‘Best’ estimate

Approximate 95% CI

North Atlantic

 

 

 

- East Greenland to Faroes

1987-89

14,800

11,000 – 20,000

 

1995

21,900

16,000 – 30,000

 

2001

25,800

20,000 – 33,000

 

2007

21,900

16,000 – 30,000

 

2015

40,800

28,000 – 59,000

- West Greenland

2005

9,800

3,230 – 29,750

 

2007

16,000

4,500 – 57,000

 

2015

2,200

1,000 – 4,900



GRAY WHALES

 

Year(s) to which estimate applies

‘Best’ estimate

Approximate 95% CI

North Pacific

 

 

 

- East

1997/98

21,100

18,400 – 24,200

 

2000/01

16,400

14,500 – 18,500

 

2001/02

16,000

14,000 – 18,400

 

2007

20,660

18,560 – 24,020

 

2008

19,040

16,670 – 24,210

 

2010

20,720

18,950 – 22,720

 

2011

20,790

18,970 – 22,640

 

2015

23,260

21,210 – 25,470

 

2016

26,640

24,310 – 29,170

 

2020

20,720

18,860 – 22,640

 

2022

16,650

15,170 – 18,340

 

 

 

 

- Pacific Coast Feeding Group

1998

133

100 – 200

 

1999

145

100 – 200

 

2000

147

100 – 200

 

2001

182

100 – 300

 

2002

210

100 – 300

 

2003

209

100 – 300

 

2004

224

100 – 300

 

2005

208

100 – 300

 

2006

195

100 – 300

 

2007

185

100 – 300

 

2008

217

100 – 300

 

2009

208

100 – 300

 

2010

201

100 – 300

 

2011

213

100 – 300

 

2012

229

100 – 300

 

2013

249

200 – 300

 

2014

245

200 – 300

 

2015

257

200 – 300

 

2016

244

200 – 300

 

2017

224

100 – 300

 

2018

211

100 – 300

 

2019

228

100 – 300

 

2020

212

100 – 300

- Western Feeding Group

1995

74

66 – 81

 

2015

200

187 – 211


   BOWHEAD WHALES

 

Year(s) to which estimate applies

‘Best’ estimate

Approximate 95% CI

North Pacific

 

 

 

- Bering-Chukchi-Beaufort Seas stock

2001

10,500

8,200 – 13,500

 

2004

12,600

7,900 – 19,700

 

2011

16,800

15,200 – 18,700

 

2019

14,000*

8,900 - 22,000

 

2019

17,200*

11,000 – 27,000

The net rate of increase of the BCB stock from 1978- 2011 has been estimated as about 3.7% per year (95% confidence interval 2.9% - 4.6%)
- Okhotsk Sea

2016

218

140 – 350

North Atlantic

     

- West Greenland feeding area

2012

1,300

900 – 1,600

 

2022

888

300 – 2,200

- East Canada - West Greenland

2013

6,400

3,700 – 11,200

- Svalbard

2015

340

100 – 900

*there are 2 estimates for the BCB stock derived through different methods, an ice based visual survey (14,000) and an aerial survey (17,200)

HUMPBACK WHALES

 

Year(s) to which estimate applies

‘Best’ estimate

Approximate 95% CI

Southern Hemisphere

     

- Partial coverage of Antarctic feeding grounds

1985/86-1990/91

10,230

5,700 – 18,300

 

1991/92-2003/04

42,000

33,000 – 52,000

- Eastern South America: Brazil

2005

6,300

4,300 – 8,600

 

Rate of increase of around 7%

- Western South America: Ecuador

2006

6,500

4,200 – 10,000

- Western Africa: Gabon

2005

6,800

4,300 – 10,500

- West South Africa

2001

 *300

200 – 400

                                      

*This estimate may represent the resident component of the population

- Eastern Africa: Mozambique

2003

6,000

4,400 – 8,400

- Eastern Africa: Madagascar 

2004

7,400

2,100 – 12,800

- East Australia

2010

14,500

12,700 – 16,600

- Oceania

1999-2005

4,300

3,300 – 5,400

North Atlantic

 

 

 

- Western North Atlantic

1993

11,600

10,000 – 13,500

- Norwegian & Barents Seas

2002-07

9,750

4,950 – 19,200

 

2008-13

12,400

6,850 – 22,500

 

2014-18

10,700

4,900 – 23,400

- Iceland / Faroe Islands

2007

18,000

7,000 – 46,000

 

2015

10,000

4,900 – 20,300

- Iceland

1995

14,600

5,100 – 41,500

- East Greenland

2015

4,200

1,800 – 9,700 

- West Greenland

2005

1,160

600 – 2,250

 

2007

2,700

1,400 – 5,300

 

2015

1,000

400 – 2,300

 

Rate of increase of around 9% 1984-2007

- Newfoundland and Labrador Sea

2016

10,500

3,800 – 28,500

North Pacific

2004-6

21,000

19,000 – 23,000

Arabian Sea

2007

80

60 – 110


RIGHT WHALES

 

Year(s) to which estimate applies

‘Best’ estimate

Approximate 95% CI

Southern Hemisphere Total

2009

12,000

 

- Southwest Atlantic

2009

3,300

 

 

2019

4,600

3,840 – 5,690

 

Rate of increase around 7%

Southern Africa

1990

1,230

1,120 –1,330 

 

2000

2,330

2,180 – 2,480

 

2009

4,400

4,000 – 4,900

 

2010

4,400

4,100 – 4,700

 

2012

5,000

4,600 – 5,600

 

2020

6,470

5,910 – 7,030

 

Rate of increase around 7%

- Sub-Antarctic New Zealand

2009

2,760

2,100 – 3,680

 

2020

4,480

2,480 – 7,030

- South central and Western Australia

2009

2,400

 

 

Rate of increase around 7%

North Atlantic

 

 

 

- West

1990

263

260-270

 

2000

308

307-311

 

2010

476

470-480

 

2019

370

350-380

 - East

Sightings are extremely rare


SEI WHALES

 

Year(s) to which estimate applies

‘Best’ estimate

Approximate 95% CI

North Pacific

 

 

 

- Central and Eastern

2010-2012

29,600

18,500 - 47,300


BRYDE’S WHALES

 

Year(s) to which estimate applies

‘Best’ estimate

Approximate 95% CI

North Pacific

 

 

 

- Western

1988-1996

32,000

19,000 – 55,000

 

1998-2002

32,000

15,000 – 66,000

 

2008-2015

41,000

24,000 – 68,000


PILOT WHALES

  Year(s) to which estimate applies Approximate point estimate Approximate 95% CI      
Central & Eastern North Atlantic

1989 

780,000 

430,000 – 1,390,000

     

BELUGA (WHITE WHALES)

 

Year(s) to which estimate applies

Approximate point estimate

Approximate 95% CI

North Pacific

 

 

 

- Okhotsk Sea

2010      

~12,000

 

- Eastern Chukchi Sea (part of)

2017      

13,300

5,100 – 34,300


HARBOUR PORPOISES

 

Year(s) to which estimate applies

Approximate point estimate

Approximate 95% CI

North Atlantic

 

 

 

- Western Baltic, Belt Sea & Kattegat

2012

40,000

25,000 – 65,000


HECTOR'S DOLPHINS

 

 

Year(s) to which estimate applies

Approximate point estimate

Approximate 95% CI

- South Island, New Zealand  

2016

14,800

11,900 – 18,500

MAUI DOLPHINS  

 

 

 

 

 

Year(s) to which estimate applies

Approximate point estimate

Approximate 95% CI

- North Island, New Zealand  

2001

96

62 – 147

   

2016

57

48 – 71

FRANCISCANA  

 

 

 

 

 

Year(s) to which estimate applies

Approximate point estimate

Approximate 95% CI

- Franciscana Management Areas (FMA) Ia  

2018

1,183

200 – 5,300

- Franciscana Management Areas (FMA) Ib  

2011

1,590

500 – 4,500

   

2017

1,521

600 – 3,900

- Franciscana Management Areas (FMA) II  

2009

9,284

5,300 – 16,100

- Franciscana Management Areas (FMA) III  

2022

43,150

23,400 – 79,400

For map of (FMA's) see link Here