Active Fishing Gears
Syllabus
Prof. Sahar Fahmy Mehanna
Fish Stock Assessment Expert
Head of Fish Population Dynamics Lab
National Institute of Oceanography & Fisheries
Fishing gears
• Objectives
• Some definitions
• Types of Fisheries
• Types of the fishing gears
• Difference between passive & active fishing gear
• Active fishing gears
• List of active fishing gear categories
• Impact of active fishing gears on the marine
ecosystem
Why???
Fisheries management includes different management
measures. Among these are technical regulations on
fishing gears in order to obtain the overall goal of high
sustainable yield in the fisheries. These regulations e.g.
on mesh size to improve the selective properties of a
fishing gear so that by-catches of juvenile fish are
reduced - in order to safeguard recruitment to the larger
size groups of a fish stock including the spawning stock.
Ecosystem approach
• It should be addressing the impact of fishing
operations not only on the target species, but
also on bycatch of or other effects on noncommercial species or habitats. Energy efficiency,
reduced pollution and improved quality of the
catch are also important aspects related to
fishing gears and fishing operations (Code of
Conduct for Responsible Fisheries, Article 7.2.2).
Some definitions
• Fishing gear
• Fishery or fishing ground
• Nursery ground
• Spawning ground
• Fishery biology
• Fish population dynamics
• Fish stock assessment
• Maximum sustainable yield
• By-catch and discard
• Fisheries management
Basics population dynamics
Bt+1=Bt+R+G-M-C
Death
(Natural mortality)
Recruitment
(+)
Whole population
(-)
(-)
Growth
(+)
Movement
Catch
(Fishing mortality)
Describing Fish Populations – the Basics
GAINS
LOSSSES
Fishing
mortality
Recruitment
Immigration
FISH STOCK
WEIGHT
Emigration
Growth
Natural
mortality
Stock assessment
Stock size
Recruitment
Assessing ‘stocks’
‘Assessing’? Involves 3 key objectives:
 calculating current biomass (absolute or
relative)
 determining the response to fishing
 Determining the ‘status’ i.e. ‘overexploited’,
‘fully exploited’, ‘under-exploited’
One Problem in Fisheries Management
"What you catch today won't be able to spawn and produce
offspring tomorrow"
versus
"You can't sell (and people can't eat) fish you don't catch;
what you don't catch today may or may not produce
offspring tomorrow."
Management choices should be viewed as a gamble:
If harvest is too big ==> less fish and money in future;
If harvest is too small ==> less fish and money now.
What is
Fisheries co-Management?
External agent
• Non
governmental
org.
• Academic
• Research Ins.
Coastal stakeholders
• tourism
• Ports
• Industry
• Hotels
• Scuba diving, etc.
Fishers
Fisheries
management
Government
• National
• Regional
• Provincial
• Municipal
• village
Fisheries stakeholders
• Boat owner
• Fish traders
• Money lenders
• Recreational fish.
• etc.
Fisheries classification
Fisheries are classified as inshore, mid-water,
pelagic, and deep-water fisheries
Inshore fisheries
Inshore fisheries target species which are
found in waters close to shore, and in depths
down to 200 m. These are the fisheries of
greatest importance to recreational fishers.
Inshore fishing methods include trawling, gill
netting and bottom longlining.
Inshore fisheries target species which are found in waters close to shore, and in depths down to
Fisheries are classified as inshore, mid-water, pelagic, or deep-water fisheries.
Inshore
200
metres.
Fisheries
These are the fisheries of greatest importance to recreational fishers.
Pelagic
Fisheries
Inshore fishing methods include trawling, gillnetting and bottom longlining.
Pelagic fisheries
• Pelagic fisheries target species which swim in
schools in surface waters, and in depths down
to 200 m. These species range over wide areas
of open ocean. There are two broad categories
of pelagic species: highly migratory species
such as tuna, and small pelagics such as
mackerel.
Fishing methods used include pair trawling,
purse seining, ocean trolling and surface
longlining.
Mid-water fisheries
Mid-water fisheries target species which are found
in depths of 200 m. Consequently, specialist
equipment is required. Fishing methods include
trawling, bottom longlining and jigging
Deepwater fisheries
Deepwater fisheries target species which are found
in depths of 600 m. Large boats and highly
specialized equipment is needed to target fish in
such deep water. The most common fishing method
is trawling.
Mid-Water
Fisheries.
Fishing gears classification
• Passive / Active
• International Standard Statistical Classification of
Fishing g Gear –60 different gears
• FAO groups into 11 main categories
• •Surrounding nets •Seine nets •Trawl nets
•Dredges •Lift nets •Falling gears
• •Gillnets and entangling nets •Traps •Hooks and
lines •Grappling and wounding gears
•Harvesting machines
 There are a variety of methods used to catch fish. The
majority of methods have an adverse effect on the
marine environment, in terms of by catch, damage to the
seabed, and negative effects on the marine food web.
Fishing methods are classified as either active or passive.
 Passive gears are those which are left in place for a
period before retrieval. They may either attract fish using
bait, or may passively wait for a fish to swim into a net
or trap. Ex. of passive gear are gill nets, longlines, traps
and pots.
• Active gears include trawls and seines which move
through the water and herd or surround the fish.
• Active or mobile gears are moved in order to
catch fish by trapping or encirclement.
These gears can be divided into those which are
towed along the seabed e.g.. Otter trawls and
beam trawls, and those which remain clear of the
seabed e.g. mid-water trawls and purse seines.
• While fishing gears have the greatest effect on
the fish populations they may also affect the
seabed and the operations of other users of the
marine environment.
To the next lecture
Active fishing gears: types and impacts