Thorny Skate Indices from the Spanish Surveys Conducted in the NAFO Regulatory Area of Divisions 3NO, 1995-2003

Since 1995, a stratified random spring bottom trawl survey in the NAFO Regulatory Area of Div. 3NO was conducted by Spain. In 2001, the trawl vessel was replaced; so, the time series indices was transformed. The transformed entire series of mean catches, abundance and biomass for Thorny skate are pr...

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Bibliographic Details
Main Author: González-Troncoso, D. (Diana)
Format: Report
Language:English
Published: Centro Oceanográfico de Vigo 2004
Subjects:
North Atlantic
Northwest Atlantic
Online Access:http://hdl.handle.net/10508/596
Description
Summary:Since 1995, a stratified random spring bottom trawl survey in the NAFO Regulatory Area of Div. 3NO was conducted by Spain. In 2001, the trawl vessel was replaced; so, the time series indices was transformed. The transformed entire series of mean catches, abundance and biomass for Thorny skate are presented for the period 1995-2000, and the lenght distribution for the period 1997-2000, and the no-transformed data for the years 2001-2003. The standard deviation are shown for abundance and biomass. The summed abundance and biomass based on conversion of the lenght frequencies are presented and compared to the estimates from the method used to convert the CPUE. A decreasing in Thorny skate abundance and biomass is observed in last years (2001-2003).

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