Pelagic
The upper layers of the ocean. This is where food is
relatively plentiful. Pelagic fish include herring, sardine
and pilchard.
Plankton
Tiny plants and animals that spend at least part of their
time on the sea surface. Primarily distributed by oceans currents. Plankton form the basis of ocean food webs.
Phytoplankton
The microscopic plant component of plankton.
Pinger
Acoustic device designed to deter marine mammals from entanglement in fishing nets.
Pole and line
Hand held or mechanically operated rod with baited hook or lure.
Pollution
The introduction by man, directly or indirectly, of
substances or energy to the marine environment with
negative effects.
Polyculture and integrated aquaculture
The farming of two or more species (animals and/or
plants) in the same aquaculture system. Waste from one species is taken up by a second species, instead of discharged into the environment.
Pond system
One of the earliest forms of aquaculture, ponds can be
either natural or artificially constructed. Catfish, carp and tilapia are commonly cultured in ponds.
Population
A biological unit representing the individuals of a species living in a specific area.
Pot
A trap used to capture fish, especially crustaceans.
Protected Name
Protected designation of origin (PDO), protected
geographical indication (PGI) and Protected Geographical Status (PGS) are geographical indications defined in European Union law to pro-tect the names of regional foods, including Arbroath Smokies and Scottish Salmon.
Purse seining
The general name given to the method of encircling a
school of pelagic fish with a large wall of net.
Population
A biological unit representing the individuals of a species living in a specific area.
Quota
A share of the Total Allowable Catch (TAC) allocated to a country, vessel, company or individual fishermen.
Raceway
A straight-sided artificial channel (usually concrete) in
which farmed fish are raised.
Round fish
Demersal fish that are rounded in transverse section,
e.g. cod, haddock and whiting (as opposed to flat fish
e.g. plaice or flounder).
Safe Biological Limits
Limits (reference points) for fishing mortality rates and
spawning stock biomass beyond which, the fishery is
unsustainable. Other criteria that indicate when a stock is outside safe biological limits include age structure,
distribution of the stock and exploitation rates. A fishery that maintains stock size within a precautionary range (a range within which the probability of reaching any limits is very small) would be expected to be sustainable.
Selectivity
Ability to target and capture fish by size and species,
allowing by-catch of juvenile and non-target species to
escape unharmed.
Shellfish
As opposed to finfish. A collective term used to describe molluscs and crustacea.
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Smoltification
The physical transformation undergone by salmonid
(salmon and trout) fish to enable them to migrate from
freshwater to seawater as part of their lifecycle.
Smolts
Juvenile fish that have undergone smoltification.
Spat
The stage in a mollusc’s lifecycle in which it goes from
being free swimming to attaching itself to a substrate.
Spawn
Release of eggs into the water, either fertilised or to
be fertilised.
Spawning stock
The mature fish responsible for reproduction in a
population(s).
Spawning Stock Biomass (SSB)
The total weight of all sexually mature fish in a population.
Static or Fixed Gears
Refers to fishing gears that are fixed to or on the seabed
e.g pots, traps or nets. These types of gears are passive
as opposed to mobile gears, e.g. trawl nets, which are
referred to as active gears.
Stock
Term given to a group of individuals or populations in a
species occupying a well-defined spatial range
independent of other stocks of the same species.
Fisheries are often managed by ‘stocks’.
Stocking density
The amount of fish in a farmed area. Usually expressed
at the weight of fish per volume of water, for example
15kg/m3.
Straddling stocks
Fish stocks that migrate through more than one country’s
Exclusive Economic Zone (EEZ).
Sweep
The rope (usually wire) between the otter board and
trawl net.
Tangle net
A type of bottom set gill net used to capture flatfish,
crustaceans and other species.
Target species
The species, or assemblage of species, which are
primarily sought in a fishery.
Teleost
Fish with a bony skeleton, as opposed to cartilaginous
fish (elasmobranchs).
Total Allowable Catch (TAC)
Maximum tonnage of a fish species that may be caught
each year within a certain area.
Trawl
A sock-shaped net with a wide mouth tapering to a small,
pointed end (the cod end) that is towed behind a vessel at
any depth.
Trolling
A type of hook-and-line method in which several
unconnected lines, each hooked and baited, are slowly
dragged behind the vessel.
Trophic
The different levels in a food chain.
Turtle Excluding Device (TED)
Turtles can be excluded from trawl nets by fitting solid
grids of various kinds into the net. These ‘trap doors’ are
designed to reduce turtle by-catch, particulary in tropical
prawn fisheries.
Zooplankton
The animal component of plankton; animals suspended
or drifting in the water column including larvae of many
fish and benthic invertebrates.
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