Research Document - 2012/049
Observer Coverage of the Atlantic Canadian Swordfish and Other Tuna Longline Fishery: An Assessment of Current Practices and Alternative Methods
By A.R. Hanke, I. Andrushchenko, and G. Croft
The sampling of the Atlantic Canadian longline fishery by the Canadian Fisheries Observer Program is reviewed to determine if the sampling is representative of the aerial and temporal extent of the fleet's fishing, the range in fishing capacity or power of its vessels, and the intensity of fishing with respect to time, area, and vessel characteristics. The precision of ratios used to scale bycatch to the whole fleet is evaluated for the existing sampling design with a view to recommending practical alternative sampling and stratification schemes and optimal levels of observer coverage for seven study species (bluefin tuna, porbeagle shark, shortfin mako, blue shark, leather back turtle, and loggerhead turtle). Further, alternative ways of scaling the observed bycatch to the entire fishery are compared and alternative methodologies are considered to see if there is a need for case specific estimation techniques.
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