Otterboard Trawling

Question 1

What is the main fishing method for both demersal and pelagic fish?

Answer 1

Bottom trawling
-Is a direct descendant of the original beam trawl

Question 2

What are otter boards?

Answer 2

-Commonly called trawl doors
-Are attached to wing ends of the nets
-Angle of the otter boards/trawl doors can be adjusted

Question 3

What are the advantages of trawling?

Answer 3

-Fish in good condition (unless deep fishing / pressure changes)
-For release of live specimens, short trawls (5 - 15 mins)
-Used in research surveys
-Quantitative index of population abundance
-Irish Groundfish surveys (IGFS)

Question 4

What are the disadvantages of bottom trawling?

Answer 4

-Big and heavy, need powerful engines
-High fuel costs
-By-catch of other species
-Mortality fish damaged in net / brought up too quickly or thrown back too late
-Can’t sample when bottom is irregular (rocky)
-Stirs up clouds of sediment that destroys marine life
-Destroys benthic communities and ecosystems
-Real possibility of species extinction

Question 5

What are the negative effects of bottom trawling?

Answer 5

-Bottom trawling destroys coral reefs and disrupts sediments and bottom dwelling life
-Plumes can be seen from space
-By-catch can make up 40 - 90% of the catch
-Degrading ecosystem resilience to other impacts like climate change

Question 6

What is a problem with the bottom trawling fishery?

Answer 6

Too many boats
-Too much high standard technology
-Too few fish

Question 7

What is the minimum mesh size for groundfish fisheries?

Answer 7

135 mm

Question 8

What are some by- catch reduction devices?

Answer 8

-Use of square mesh panels in the codend
-Turtle exclude devices

Question 9

How long does the trawl extend from the trawl doors?

Answer 9

Extends 200 m