Estimators of discards using fishing effort as auxiliary information with an application to Iberian hake (Merluccius merluccius) exploited by the Portuguese trawl fleets

Estimating discards is an important issue for fisheries management so that total mortality caused by fishing is considered. In 2003, a sampling programme addressing Iberian hake discards by the Portuguese fleets was implemented according to the requirements of the European Commission Data Collection Regulation (Reg. EC No 1543/2000). A preliminary analysis of the data collected showed trip and haul duration to be potential sources of bias, because their relationship to discards per unit effort (DPUE) was not linear. This paper develops estimators for discards by weight using fishing effort as auxiliary information, describes a jack-knife procedure to identify influential observations, applies the methodologies to Iberian hake as a case study and compares the results obtained by each estimator.

GAMITO JARDIM José Ernesto;  FERNANDES Ana Cláudia; 

2013-01-18

ELSEVIER SCIENCE BV

JRC69118

0165-7836,   

http://www.sciencedirect.com/science/article/pii/S0165783612003505,    https://publications.jrc.ec.europa.eu/repository/handle/JRC69118,   

10.1016/j.fishres.2012.12.006,