skip to content
Government of Western Australia - Department of Fisheries

Glossary - P

A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z


Pair trawling
Trawling by two vessels steaming in parallel with the net towed between them.  Very large nets can be held open and towed in this manner.  The net is generally hauled alternatively aborad the two vessels for processing the catch.

To render helpless; to cripple or deaden.

A plant or animals that lives in or on another organism from which it draws nutrition.

Pectoral fin
Pair of fins situated just behind the head in fishes that help control the direction of movement

Associated with the surface or middle depths of a body of water.

Pelvic fins
The first pair of ventral fins of fishes.

Penaeid prawn
Prawns of the infraorder Penaeidea.  This infraorder includes the bulk of the prawns taken in commercial quantities in Australia.  Female penaeid prawns release their eggs directly into the sea.

Lasting a long time, often throughout the year or several seasons.

The horny outer layer found on the shells of many species of molluscs.

Small epiphytic algae.

An unwanted, destructive or damaging organism.

Professional Fishing Association

A measure of the concentration of hydrogen ions (H+) and hydroxide ions (OH–) in a solution, measured on a scale from 0 to 14 units.

Derived from phenotype, which means the visible or otherwise measureable physical or biochemical characteristics of an organism.

Photic zone
The surface layers of the seas and oceans penetrated by light and inhabited by photosynthetic organisms.

Process by which green plants convert carbon dioxide to carbohydrates and oxygen using sunlight for energy.

Having a tendency to adjust orientation in response to light. A plant or sedentary animal that is positively phototaxic will lean or grow toward light. One that is negatively phototaxic will lean or grow away from light.

Lobster larvae

A chief taxonomic category, between kingdom and class, into which are grouped organisms of common descent that share a a fundamental pattern of organisation.

Microscopic plants that drift in open water.

Pearling Industry Advisory Committee

A suborder of marine mammals including seals, sea lions and walruses

An agreed procedure to meet goals, objectives or other requirements.

Tiny, free-floating aquatic plants and other photosynthetic organisms.

Synthetic or natural organic materials that may be shaped when soft and then hardened.

Plate boundary
The location where two tectonic plates meet. There are three types of plate boundaries, described based on their movement pattern; convergent boundaries where plates collide, divergent boundaries where plate pull apart, and transform boundaries where plates grind past each other.

Plate-sized fish
A fish normally 30 cm or above that can be served whole on a dining plate.

Plateau (submarine)
A large, relatively flat region that rises above the ocean floor.

Paddle-like swimming limbs on the abdomen of crustaceans.

An aerial root specialized for gaseous exchange

Contamination of soil, water, or air by the discharge of waste or other offensive material that can damage animals, plants or ecosystems.

A class of worms, usually marine.

A natural or synthetic compound consisting of large molecules made up from a series of similar or identical smaller molecules called monomers. Polymers are generally lightweight, durable, moldable and non-conductive.

A cup-shaped animal (Cnidaria) that is usually attached at the base (sessile) with a row of tentacles surrounding the upper rim.

Animals inhabiting a specified area.

Possession limit
Is the maximum number or amount of species that a person can control or transport at any one time.

A phylum of animals characterised by a body that is pucntuated with microscopic holes or pores, as well as one or more larger round openings or vents.

Potable water
Water of a quality suitable for drinking.

Precautionary principle
Where there are threats of serious irreversible environmental damage, lack of full scientific certainty should not be used as a reason for postponing measures to prevent environmental degradation.  In the application of the precautionary principle, public and private decisions should be guided by: (i) careful evaluation to avoid, wherever practicable, serious or irreversible damage to the environment; and (ii) an assessment of the risk-weighted consequences of various options.

Any of all forms of water particles, whether liquid or solid, that fall from the atmosphere and reach the earth’s surface.

An animal that preys upon other animals.

An animal hunted or obtained for food.

Primary consumer
An animal that gets its energy from primary producers.

Primary producer
Organisms (typically plants or algae) capable of making their own food, usually through photosynthesis, and are therefore a major food source for primary consumers.

Principal Fishing Areas
Approximate diagrammatic representation of the main fishing areas of a fishery or fishing activity.

Having its original purity. Undamaged or unpolluted.

To be treated by a special process, usually to add value or increase shelf life.

Production rate of new organic material in an ecosystem.

Not having a membrane-bound nucleus.  Bacteria and cyanobacteria.

A relationship between things or parts of things with respect to comparative magnitude, quantity or degree.

Protandrous hermaphrodite
Animal that begins adult life as a male and has the ability to change sex to a female later in life.

Protected species
Species that may not be taken by either commercial, charter or recreational fishers.

A group of microscopic, single-celled organisms that are neither plant nor animal.

Protogynous hermaphrodite
Animal that begins adult life as a female and has the ability to change sex to a male later in life.

Purse Seine Management Advisory Committee

A newborn shark.

Late larval stage in the development of a western rock lobster and other crustaceans.

Withholding feed and keeping animals in clean water remove wastes from the gut.

Purse seine
A fishing method capable of harvesting large quantities of surface-schooling pelagic fish by surrounding the school with a net.

Purse seine net
Used to surround schools of fish and is pulled to close at the bottom.

Patrol Vessel

Pyloric caeca
Finger like pouches connected with the stomach, in which digestion takes place.

Last modified: 27/11/2012 11:53 AM

© All contents copyright Government of Western Australia. All rights reserved. ABN: 18 951 343 745


© This work is copyright. You may display, print or reproduce this material only in an unaltered format for your personal or non-commercial use, or for use within your organisation. Apart from any use permitted under the Copyright Act 1968, all other rights are reserved.


The information and advice provided by the Department of Fisheries website is made in good faith and is from sources believed to be reliable and accurate at the time of release onto the website. Changes in circumstances after a document is placed on the website may affect the accuracy of the information. Full disclaimer details are available at