Pots / Traps / Baskets
Gear & Effort / Total Catch
http://www.wildlifenews.alaska.gov
http://coastalvoices.blogspot.com/200
9_09_01_archive.html
Objectives
 Describe 3 components of pot gear
 List 2 types of specialized equipment you may
encounter on pot vessels
 Demonstrate your ability to complete the Gear
Description and Total Effort / Total Catch forms
What is pot/trap fishing?
 Pots/traps – use bait to attract fish in on or near bottom
 Fishing occurs on continental shelf or slope
Schoolmeester & Baker 2009
What is pot/trap fishing?
 Pots/traps – use bait to attract fish in on or near bottom
 Fishing occurs on continental shelf or slope
 Primary targets: fish, crab, octopus, shrimp
What is pot/trap fishing?
 Pots/traps – use bait to attract fish in on or near bottom
 Fishing occurs on continental shelf or slope
 Primary targets: fish, crab, octopus, shrimp
 Bait = fish or squid depending on target
What is pot/trap fishing?
 Hook & line gear – uses bait to attract fish on or near bottom
 Usually on continental shelf & slope
 Primary targets: gadoids, sharks
 Bait = fish or squid depending on target
 Fishery impacts – cetacean entanglement
http://www.americanreef.o
rg/news.html
John Calambokidis, Cascadia Research
http://wildwhales.org/
Data collection priorities

Estimate effort and total catch for each gear
deployment;

Identify every individual caught on each randomly selected set (or
subsample within the set) and estimate percent retained;
Collect biological information on target and other species as
requested;
Record all sightings and interactions with marine mammals and sea
turtles;



Record vessel and fishing gear characteristics.
Fishing with Pots / traps / baskets
Groundline /
Longline
Longline
ofof
baskets
pots
Image: Hanrahan et al. (1997)
Single
pots
Gear components – gear markers
Drawing modified from
Hanrahan et al. 1997
http://store.vernondeon.com/
http://williamsmarineltd.ca/Manfacturing.html
Gear components - pots
Funnel / opening
www.seattlemarine.net
http://coastalvoices.blogspot.com
Gear components - pots
http://delamersailssouth.blogspot.com
Traps
Nova Scotia, 2009
K. Dietrich
Gear – hauling devices
 Line hauler
http://www.mustad-autoline.com/
 Groundline drum
http://www.mustad-autoline.com/
http://www.qmarine.com
How is gear fished?
 Strategies
 Deployment
(videos –
1, 2)
How is gear fished?
 Strategies
 Deployment
 Retrieval
Gear Description - Traps
 1 form per trip
Pot shapes
Traps – Effort / Total Catch
 Entry for every day on board
 1 entry for each set
 Fishing effort – time & amount of gear fished
 Catch per unit effort (CPUE)
Defining a set
 Longline of baskets – total baskets
connected by one line
 Deployed individually – coordinate w/
Captain
◘ ◘ ◘ ◘ ◘ ◘
 1 set of 18
 3 sets of 6
◘ ◘ ◘ ◘ ◘ ◘
◘ ◘ ◘ ◘ ◘ ◘
Choosing a set to sample
 Same general rules as for demersal longline
 Use random sample table if necessary
Total Catch Estimation
 Total catch must be estimated for every set.
 Weigh entire catch (method 1)
 Captain / vessel estimate (method 5)
 Catch / effort ratio (method 6) - unsampled
Σ Sample weights from similar sets
Σ Tallied pots from similar sets
X
Total pots in unsampled set
 Catch / effort ratio (method 7) – tally sample
Sample weight (kg)
Pots in sample
X
Total pots in set
References
Hanrahan, J., D. J. Melindy, and J. V. Pelrine. 1997. At-sea Observer
Program Operations Manual: A Training Aid and Field Reference.
National At-sea Fisheries Observer Program, Department of
Fisheries and Oceans, Ottawa, Canada.
Slack-Smith, R. J. 2001. Fishing with traps and pots. FAO Training
Series No. 26, FAO, Rome.
Watson, R., E. Hoshino, J. Beblow, C. Revenga,Y. Kura, and A.
Kitchingman. 2004. Fishing Gear Associated With Global Marine
Catches. Fisheries Centre Research Reports 12.
http://www.fao.org/fishery/vesseltype/230/en Courtesy of Joël Prado - FAO/FIIT
Vessel features
Choosing pots (baskets) to sample
◘ ◘ ◘ ◘ ◘ ◘
◘ ◘ ◘ ◘ ◘ ◘
(e.g. 1/3 of baskets) – spatial
sample frame
 Choose sample method random or systematic random
 Select random numbers
 Count/weigh everything from
baskets sampled
◘ ◘ ◘ ◘ ◘ ◘
 Population: all baskets in 1 set
 Sampling unit: single basket
 Decide on how much to sample