Romanov Bycatch in the tnna purse seine fisheiies of the western Indian Ocean 



101 



1,000 1 



900 



800 - 



700 



S 600 



f 500 



z 400 



300 



200 



100 







Billfisties 



A 



DThis study 

  I-ATTC1993 

 Dl-ATTC 1994 



Free-swimming Log-associated Marine mammals 



Small fishes 



2 8 



DThis study 

  l-ATTC 1993 

 Dl-ATTC 1994 



00 42 24 



Free-swimming Log-associated H/larine mammals 



450 

 400 

 350  

 300 

 250 

 200 

 150 

 100 

 50 

 



Stiarl^s 



Free-swimming 



Log-associated IVIarine mammals 



Dolptiinfisties, wahoo, rainbow runners 



D 



07 



DThis study 

  l-ATTC 1993 

 Dl-ATTC 1994 



02 1 Of 



Free-swimming 



Log-associated Manne mammals 



Sea tunies 



DThis study 

  l-ATTC 1993 

 Dl-ATTC 1994 



Free-swimming Log-associated t^anne mammals 



Figure 5 



Bycatch levels in numbei's per set by groups of species and by types of schools in the western Indian Ocean and eastern Tropical 

 Pacific (Anonymous, 1997). 



14^'r . respectively), which is explained by the fact that the 

 SFA data included Japanese vessels known to fish on log- 

 associated schools only. Nevertheless, the SFA values and 

 those from our obser\'ers were on the same order of mag- 

 nitude. Proceeding from this, I estimated the ratio of sets 

 on various school types and the magnitude and species 

 composition of bycatch by the French and Spanish ves- 

 sels. These values were close to those for the Soviet fleet 

 employing similar fishing tactics.-^ 



Thus, the average bycatch estimates presented in this 

 study can be extrapolated for this period to the total WIO 

 purse-seine catch of principal fishing nations targeting all 

 types of schools.-^** Estimates of bycatch from log-associat- 



ed schools, I believe, can be extended, with some caution, 

 to the pooled purse-seine catch of Japan and Mauritius in 

 the WIO. 



The annual purse-seine catches of yellowfin and skip- 

 jack tunas by fleets targeting all types of schools (France, 



Data from logbooks (Cort, 1992) show a lower proportion of sets 

 and of catches on whale-associated .schools for Spanish vessels, 

 but in the author's view a comparison of data collected in the 

 same way (by observers) is preferable. 



France and Spain (along with catch from the vessels from 

 these two countries flying "flags of convenience" [Panama, Cote 

 d'lvoire, and recently Belize] and applying the same fishing 

 tactics), and USSR (recently Russia or Liberia). 



