The brown trout Salmo trutta L. populations in the river Lima catchment

• Type: Article in International Scientific Journal
• Date: 1999

Authors

Maia, CFQ (Author) Other; Valente, ACN (Author) FCUP

Journal

Title: Limnetica

Vol. 17

Pages: 119-126

ISSN: 0213-8409

Publisher: Associacion Espanola de Limnologia

Indexing

ISI Web of Knowledge

Scopus - 2 Citations

Other information

Authenticus ID: P-007-GYM

Abstract (EN): All the Lima tributaries are considered to be salmonid Rivers. As a result of intense angling pressure, some tributaries are subject to special angling regulations. However, a correct management of populations of brown trout (Salmo trutta) needs to be based on knowledge of these populations. The populations of six tributaries (Vade, Estorãos, Trovela, Labruja, Tamente and Froufe) have been characterised. From September 1995, electrofishing surveys have been conducted every three months in the Rivers Vade (four sites), Estorãos (two sites) and Trovela (one site). One annual sample has been obtained from Labruja, Tamente and Froufe. Brown trout is the only fish species present in all sampling sites, representing more than 50% of total catch in the upstream sites. Brown trout densities varied along the River length and also within the tributaries sampled. Mean values were always greater than 10 ind/100 m 2, but in some sites more than 20 ind/100 m2 were found. Mean trout biomass was 285.5 gFW/100 m2, ranging from 23.04 to 727.04 gFW/100 m2. Population age-structure showed within-site variation, i.e. 0+ and 1+ fish were dominant at most sites, although 5+ to 7+ trout were also captured. The improve conservation efforts of the brown trout needs of more data, related to angling pressure (e.g. number of angler visits and catches) and a more effective control of this. © Asociación Española de Limnología.

Language: English

Type (Professor's evaluation): Scientific