Abundance Estimation of Demersal Fishes in the Artificial Reef Area by TV Camera Census and Fishing Gear Sampling

Abstract

A combination method of TV camera census and fishing-gear sampling was devised to estimate demersal fish abundance on artificial reefs. Capturing area (A') of a fishing gear for a fish species was defined as the area Where all individuals of the species could be captured by the gear, i.e. catchability q=1. When A'was determined, density (D) and biomass (B) can be estimated by the fishing gear, calculated from the number captured (C) and their weight (W) using the equations, D =C/A'and B= W/A'. we evaluated A' for a bottom trammel net and a bottom long line by sampling where fish densities were measured by a TV camera census. The density and biomass of the dominant fishes on Okama artificial reef situated at a depth of about 130 m off Kamaishi, Japan, Were estimated by using these two fishing gears.