Table 1. Summary table of mitigation measures
Type of Measure	Fishery suitability		Stage of development	Compliance monitoring needs	Relative cost: initital and ongoing	Safety factor for crew	Negative impact on		Seabird catch reduction efficiency
	Demersal	Pelagic					Target catch	Non-bird bycatch
Weighting the longline gear	good	moderate	partly developed	low	high initial, low ongoing	caution needed	reduction concerns	specific problem potential	very high
Thawing bait and/or puncturing swim bladder	poor	good	partial development and testing	high at present	low ongoing	safe	no	no	moderate potential
Line-setting machine	moderate	moderate	developed, partly tested	none	moderate initial, low ongoing	safe	no	no	moderate potential
Below-the-water setting	moderate	moderate	under development	none	high initial	safe	no	no	total
Bird scaring line (streamers lines, buoy lines)	good	moderate	developed, tested, refinement needed	variable, by observation	low ongoing	safe	no	no	high but variable
Bait Casting Machine	none	poor	developed, partly tested	none	high initial	to consider	no	no	moderate potential
Brickle curtain	good	good	developed	variable, by observation	low	safe	no	no	very high
Artificial baits or lures	poor	poor	concept only	none	high initial, low ongoing	safe	unknown	unknown	high potential
Hook modifications	poor	good	at concept stage	none	moderate initial	safe	unknown	unknown	moderate potential
Acoustic deterrent	moderate	poor	limited testing	high	low initial	to consider	no	no	unknown, but very low likelihood
Water cannon	moderate	poor	limited testing	high	moderate initial	safe	no	no	unknown but low likelihood
Magnetic deterrent	moderate	poor	limited testing	low	moderate initial	to consider	no	no	very low likelihood
Reduce visibility of bait (e.g. night setting)	good	good	currently in use in some fisheries	moderate by observation	widely none, locally high initial	safe	reduction concerns	increase potential	very high
Reduce the attractiveness of the vessel (e.g. reduce offal discharge)	good	moderate	developed	none	moderate initial	safe	no	no	very high (line hauling)
Area and seasonal closures	poor	poor	not used	high	unknown	safe		no	high potential
Preferential licensing for vessels	good	good	concept	variable	unknown	safe	no	no	high
Release live birds	moderate	moderate	developed	none	no	safe	no	no	moderate potential

Source: Brothers, N.P., Cooper, J., and Lokkeborg, S. The Incidental catch of seabirds by longline fisheries: worldwide review and technical guidelines for mitigation. FAO Fisheries Circular. No 937. Rome, FAO, 1999. 100p.