Anganuzzi Detecting trends in dolphin abundance indices 



193 



Northern offshore spotted dolphin 



Southern offshore spotted dolphin 



- Unsorled smoothed 



estimate 

  Lower confidence 



bound 



Upper confidence 



bound 



■- — - ' Unaorted smoolbed 

 estimate 



Lower confidence 



bawl 



Upper confidence 



bound 



Distance between estimates (in years) 



Northern and southern offshore combined 



Distance between estimates (in years) 



Eastern spinner dolphin 



— Unsorted smoothed 

 estimate 



--- Lower confidence 

 botxid 



- Upper confidence 



bound 



Distance between estimates (in years! 



Distance between estimates (in years) 



Figure 9 



Correlation between smoothed estimates as a function of the separation in years between estimates for four stocks of dolphin in the 

 eastern Pacific Ocean: Offshore spotted Stenella attenuata and spinner dolphin Stenella longirostris. 



Citations 



Anganuzzi, A.A., & S.T. Buckland 



1989 Reducing bias in estimated trends from dolphin 

 abundance indices derived from tuna vessel 

 data. Rep. Int. Whaling Comm. 39:323-334. 

 Anganuzzi, A.A., S.T. Buckland, & K.L. Cattanach 



1991 Relative abundance of dolphins associated with 

 tuna in the eastern tropical Pacific, estimated from 

 tuna vessel sightings data for 1988 and 1989. Rep. 

 Int. Whaling Comm. 41. 



Anganuzzi, A.A., K.L. Cattanach, & S.T. Buckland 



1992 Relative abundance of dolphins associated with 

 tuna in the eastern tropical Pacific in 1990 and trends 

 since 1975, estimated from tuna vessel sightings 

 data. Rep. Int. Whaling Comm. 42:541-546. 



Buckland, S.T. 



1984 Monte Carlo confidence intervals. Biometrics 

 40:811-817. 



Buckland, S.T, & A.A. Anganuzzi 



1988 Trends in abundance of dolphins associated with 

 tuna in the eastern tropical Pacific. Rep. Int. Whal- 

 ing Comm. 38:411-437. 

 Buckland, S.T, K.L. Cattanach, & A.A. Anganuzzi 



1992 Estimating trends in abundance of dolphins asso- 

 ciated with tuna in the eastern tropical Pacific Ocean, 

 using sightings data collected on commercial tuna 

 vessels. Fish. Bull, U.S. 90:1-12. 

 Edwards, E.F., & P.C. Perkins 



1992 Power to detect linear trends in dolphin abun- 

 dance: Estimates from tuna-vessel observer data, 

 1975-89. Fish. Bull., U.S. 90:625-631. 

 Gerrodette, T. 



1987 A power analysis for detecting trends. Ecology 

 68:1364-1372. 

 IWC (International Whaling Commission) 



1992 Report of the sub-committee on small ceta- 

 ceans. Rep. Int. Whaling Comm. 42:178-228. 



