These measures are modified from Appendix T of the Report of the Ad Hoc Consultation on the Role of Regional Fishery Agencies in Relation to High Seas Fishery Statistics (La Jolla, California, USA, 13-16 December 1993), FAO Fisheries Report No. 500. The measures are suggested for the purpose of carrying out stock assessment. The measures may require modification or additional information before being appropriate for other purposes.
FISHING GEAR |
EFFORT MEASURE DESCRIPTORS |
DEFINITION |
FIRST PRIORITY |
||
Surrounding nets (e.g. purse seines) |
Number of sets |
Number of times the gear has been set or shot, whether or not
a catch was made. This measure is appropriate when school size and packing
density is related to stock abundance or sets are made in a random
manner. |
Surrounding nets (e.g. purse seines) |
Searching time |
This represents time on the grounds less time spent shooting
net and retrieving the catch as well as time hove to. This measure is
complicated by the use of aircraft spotting as well as by the dissemination of
information from vessel to vessel. The measure is appropriate when school size
and packing density are unrelated to stock abundance and a set is only made when
a school has been located. |
Surrounding nets (e.g. purse seines) if fishing with Fish
Attracting Device (FAD) |
Number of hours since last fishing this FAD |
Time in which FAD (Fishing Attracting Device) is left in the
water since it was last fished. |
Boat seines (Danish seine, etc.) |
Number of hours fished |
Number of hours during which the seine was on the bottom and
fishing. |
Beach seines |
Number of sets |
Number of times the gear has been set or shot, whether or not
a catch was made. |
Castnet |
Number of casts |
Number of times the gear has been cast, whether or not a catch
was made. |
Trawls |
Number of hours fished |
Number of hours during which the trawl was in the water
(midwater trawl), or on the bottom (bottom trawl), and fishing. |
Boat dredges |
Number of hours fished |
Number of hours during which the dredge was on the bottom and
fishing. |
Gillnets (set or drift) |
Number of effort units |
Length of nets expressed in 100-metre units multiplied by the
number of sets made (= accumulated total length in metres of nets used in a
given time period divided by 100). |
Gillnets (fixed) |
Number of effort units |
Length of net expressed in 100-metre units multiplied by the
number of times the net was cleared. |
Lift net |
Number of hours fished |
Number of hours during which the net was in the water, whether
or not a catch was made. |
Traps (uncovered pound nets) |
Number of effort units |
Number of days fished times the number of units
hauled. |
Covered pots and fyke nets |
Number of effort units |
Number of lifts times the number of units (= total number of
units fished in a given time period). |
Longlines (set or drift) |
Numbers of hooks |
Number of hooks fished in a given time period. |
Pole-and-line |
Number of days fished |
The number of days (24-hour periods, reckoned from midnight to
midnight), on which any fishing took place, including days during which
searching took place without fishing. |
Rod-and-reel (recreational) |
Number of line-hours |
Number of hours during which the lines were in the water times
number of lines used. |
Troll |
Number of line-days |
Total number of line days in the given time period. |
Jigs (hand and mechanical) |
Number of line-days |
Total number of line days in the given time period. |
Other small scale net gears |
Number of operations |
Those small scale gears including push net, scoop net,
drive-in net etc. Number of fishing operation, whether or not a catch was
made. |
Other small scale stationary gears |
Number of hours fished |
Those gears include guiding barriers, bag net, stow net,
portable net, etc. Number of hours during which the gears were in the water for
fishing, whether or not a catch was made. |
Harpoons, spears etc. |
Number of days fished |
The number of days (24-hour periods, reckoned from midnight to
midnight), on which any fishing took place, including days during which
searching took place without fishing. |
SECOND PRIORITY |
||
Boat seines (Danish seine, etc.) |
Number of sets made |
Number of times the gear has been set or shot, whether or not
a catch was made. |
Trawls |
Number of sets made |
Number of times the gear has been set or shot (either in
mid-water or to the bottom), whether or not a catch was made. |
Lift net |
Number of hours fished |
Number of times the net was set or shot in the water, whether
or not a catch was made. |
All gears |
Number of days fished |
The number of days (24-hour period, reckoned from midnight to
midnight) on which any fishing took place. For those fisheries in which
searching is a substantial part of the fishing operation, days in which
searching but no fishing took place should be included in "days fished"
data. |
THIRD PRIORITY |
||
All gears |
Number of days on ground |
The number of days (24-hour periods, reckoned from midnight to
midnight), in which the vessel was on the fishing ground, and includes in
addition to the days fishing and searching also all the other days while the
vessel was on the ground. |
FOURTH PRIORITY |
||
All gears |
Number of days absent from port |
The number of days absent from port on any one trip should
include the day the fishing craft sailed but not the day of landing.
Where it is known that fishing took place on each day of the trip the number of
"days absent from port" should include not only the day of departure but also
the day of arrival back in port. Where on any trip a fishing craft visits more
than one "fishing area" (as defined for statistical purposes) an appropriate
fraction of the total number of days absent from port should be allocated to
each "fishing area" in proportion to the number of days spent in each, so that
the total number of days absent on the trip will be the sum of the number of
days allocated to all of the different "fishing areas" visited. |
FIFTH PRIORITY |
||
All gears |
Number of trips made |
Any voyage during which fishing took place in only one
"fishing area" is to be counted as one trip. When in a single trip a craft
visits more than one "fishing area" an appropriate fraction of the trips should
be apportioned to each "fishing area" in proportion to the number of days spent
fishing in each, so that the total number of trips for the Statistical Area as a
whole will be the same as the sum of trips to each "fishing area". |