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- Pair trawling - occurs when two trawlers tow the same net. Otter boards are not needed and very large nets can be held open and towed in this manner.
- Panmictic - refers to random mating where all individuals within a population are potential partners.
- Parameter - parameter in fisheries is a characteristic measure of some aspect of a fish stock. it is usually expressed as a numerical value, such as the "natural mortality rate".
- Pelagic zone - any water in the sea that is not close to the bottom.
- Pelagic fish - fish that spend most of their life swimming and feeding in the pelagic zone, as opposed to resting on or feeding off the bottom. Examples are tuna and most sharks.
- Phosphate - a chemical compound containing phosphorus and oxygen, commonly found in agricultural fertilizers and land runoff.
- Photic zone - "sun lit" zone extending downward from a lake or ocean surface to the euphotic depth where the light intensity falls to one percent of that at the surface. The photic zone exposed to sufficient sunlight for photosynthesis to occur. The depth of the photic zone can be greatly affected by seasonal turbidity. Typical euphotic depths vary from only a few centimetres in highly turbid eutrophic lakes, to around 200 metres in the open ocean. About 90% of all marine life lives in this region.
- Plankton - consist of any drifting organisms (animals, plants, archaea or bacteria) that inhabit the pelagic zones, particularly the surface areas, of oceans or bodies of fresh water.
- Population - See stock.
- Population dynamics - The study of fish populations and how fishing mortality, growth, recruitment, and natural morality affect them.
- Precautionary principle - a moral and political principle which states that if an action or policy might cause severe or irreversible harm to the public or to the environment, in the absence of a scientific consensus that harm would not ensue, the burden of proof falls on those who would advocate taking the action
- Predator-Prey - A predator is a species that feeds on other species. A prey is a species that is being eaten by a predator.
- Primary Productivity - A measurement of plant production that is the start of the food chain. Much primary productivity in marine or aquatic systems is made up of phytoplankton, which are tiny one-celled algae that float freely in the water.
- Projection - With the help of a mathematical model as a numerical representation of the population, a projection is a prediction of what may happen in the future under a variety of conditions.
- purse seine - a fishing technique capable of harvesting large quantities of surface-schooling pelagic fish by surrounding the school with a net. A line which passes through rings on the bottom of the net can be tightened to close the net so that the fish are unable to escape. See also Danish seine.
- Phytoplankton - tiny, free-floating, photosynthetic organisms in aquatic systems.
Read more about this topic: Glossary Of Fishery Terms