The initial zone of growth formed within the first year.
Divergence of water currents or the movement of surface water away from land can lead to a \'welling-up\' of deeper water that is usually richer in nutrients than is surface ...
Inhabiting surface waters rather than the sea floor. This term is usually applied to free-swimming species such as tunas and sharks; see also demersal and epipelagic.
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 ...
Individual items, as in the expression "two dollars a piece". Individual fish.
The collection of small or microscopic organisms, including algae and protozoans, that float or drift in great numbers in fresh or salt water, especially at or near the surface, ...
Translucent growth forming on the edge of the otolith; not counted in the age class designation.
Also called pole-and-live-bait fishing, involves attracting schools of fish to the vessel with live or dead bait, then getting them into a feeding frenzy with more bait ...
Composition of a population in terms of size, stock (genetic or regional), age class, sex, etc.
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 ...
A measure of reproducibility; in age determination it relates to the variability between or within readers.
1. The total elaboration of new body substance in a stock in a unit of time, irrespective of whether or not it survives to the end of that time. Also called: net production; ...
When applied to fish stocks the term productivity gives an indication of the birth, growth and death rates of a stock. A highly productive stock is characterised by high ...
With the help of a mathematical model as a numerical representation of the population, a prediction of what may happen in the future under a variety of conditions.