Effect of blue dyed bait on incidental seabird mortalities and fish catch rates on a commercial longliner fishing off East Cape, New Zealand

Authors: 

Lydon, G., Starr, P.

Year: 

2004

Journal/Publisher Name: 

New Zealand Department of Conservation

Page #s: 

1-22

Contact information: 

The NZ Seafood Industry Council Ltd. Box 24-901 Wellington, New Zealand greg@seafood.co.nz paul@starrfish.net
Summary: 

Experiments using squid dyed with Brilliant Blue dye were undertaken aboard tuna longline vessels off East Cape, New Zealand, to determine the dyed baits ability to reduce the incidental capture of seabirds.  Significant differences in catch rates between bait types were observed when all species were combined and for seabird mortality, but the authors identified problems with the statistical design, which make the results not very convincing and therefore inconclusive.  In addition, at sea observations of seabird behavior during the deployment of the longline gear, suggest the dye did not effectively camouflage the bait.  Instead the authors suggest seabirds may reject the blue dyed bait due to its color after either seeing it or investigating it through pecking and/or eating.