416 



Fishery Bulletin 105(3) 



Squid only Fish bait Squid only Fish bait 

 No catch damage Catch damage 



Figure 5 



Predicted (symbols) and observed (bars) 

 interaction rates (number of positive sets/ 

 total number of observed sets) for Risso's 

 dolphins {Grampus griseus) in the Northeast 

 Coastal fishing area (A), the Mid-Atlantic 

 Bight fishing area (B), and other areas (C) 

 as a function of bait type and observed catch 

 damage. Error bars indicate 95% confidence 

 intervals of predicted values. Note the dif- 

 ference in the v-axis scales. 



20 40 60 80 100 120 140 160 



Distance from 200-m Isobath (km) 



Figure 6 



Predicted (lines) and observed (symbols) 

 interaction rates of gear (number of positive 

 sets/total number of observed sets) with 

 Risso's dolphins {Grampus griseus) in the 

 Northeast Coastal fishing area (A), the Mid- 

 Atlantic Bight fishing area (B), and other 

 areas (C) with increasing distance from the 

 200-m isobath and observed catch damage. 

 Error bars indicate 959c confidence intervals 

 of predicted values. Note the difference in 

 the v-axis scales. 



or entanglement. In other regions, sperm whales and 

 killer whales are thought to respond to the sound of 

 the vessel engines and winches when bottom longlines 

 are hauled back on board (Kock at al., 2006). Longer 

 haulback times associated with longer mainlines may 

 thus further increase the opportunity for marine mam- 



mals to detect fishing gear. Improving the understand- 

 ing of how and why marine mammals are attracted 

 to longline gear will help both to reduce the economic 

 losses due to depredation of catches and the impacts 

 of commercial fishing activities on marine mammal 

 populations. 



