Glossary of Fishery Terms - I

I

• Incidental catch - the catch of non-fish species, caught in the course of commercial fishing practices. Examples of non-fish species are seabirds, and marine mammals and reptiles, such as dolphins, seals and sea turtles. Incidental mortality can be contrasted with bycatch, which is a general term for the catch of all fish and non-fish species other than the targeted species.

• Individual transferable quota (ITQ) - a management tool by which the total allowable catch quota is allocated to individual fishers or companies who have long-term rights over the quota or can transfer it to others by sale, lease, or will. See also quota.

• Intertidal - The intertidal zone is the region of land which is submerged during high tide and exposed during low tide.

• Introduced species - Species brought into an area where it does not naturally occur, but is able to survive and reproduce there.

• Invertebrates - animals without a backbone, such as octopus, shellfish, jellyfish and corals. See also vertebrates.

• Isobath - a contour line linking regions of the same depth.

• Isopleth - contour line joining points corresponding to similar values. Often used to plot yield-per-recruit values on a graph showing the changes as a function of size-at-first-capture and fishing mortality.

• Isopods - group of small crustaceans that includes fish lice.

• isotherm - contour line connecting points with the same temperature.

Summary of 2006 IUCN Red List categories.

• IUCN - the International Union for the Conservation of Nature and Natural Resources is the world's main authority on the conservation status of species. Their system divides threatened species into three categories: critically endangered (CR), endangered (EN), and vulnerable (VU). They also list extinctions that have occurred since 1500 AD and taxa that are extinct in the wild.

• IUCN Red List - the IUCN Red List of Threatened Species (also known as the IUCN Red List or Red Data List), created in 1963, is the world's most comprehensive inventory of the global conservation status of plant and animal species.