34 
National Marine 
Fisheries Service 
NOAA 
Abstract —Many studies underscore 
the importance of incorporating the 
effect of environmental data within 
a life-history-stage-specific frame¬ 
work for determining the recruit¬ 
ment and survival of small pelagic 
fish. The recruitment of anchovy 
(Engraulis encrasicolus ) in the Gulf 
of Cadiz (NE Atlantic) is sensitive 
to the effect of intense easterlies, 
stratification of the water column, 
and discharges from the Guadalqui¬ 
vir River on early life stages. As a 
proof of concept, we have devel¬ 
oped the basis for a new Bayesian 
model with a dual time step reso¬ 
lution: monthly for juveniles and 
adults, and weekly for earlier life 
stages. This dual time step resolu¬ 
tion resolves environmental effects 
on prerecruits while simulating the 
effect of fishing on recruits. Our es¬ 
timates for juvenile abundances are 
validated with field data. The Bayes¬ 
ian framework accounts for the un¬ 
certainty, thus providing consistent 
length-frequency estimates and a 
plausible environmentally driven 
stock-recruitment relationship. 
Manuscript submitted 19 January 2017. 
Manuscript accepted 2 November 2017. 
Fish. Bull. 116:34-49 (2018). 
Online publication date: 13 December 2017. 
doi: 10.7755/FB.116.1.4 
The views and opinions expressed or 
implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
Fishery Bulletin 
hr established in 1881 -<f. 
Spencer F. Baird 
First U S. Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Embedding the effect of environmental conditions 
on recruitment and survival of the European 
anchovy {Engraulis encrasicolus ): a Bayesian model 
with dual-time resolution 
Margarita M. Rincon (contact author) 1 
Ignacio A. Catalan 2 
Samu Mantyniemi 3 
Diego Macias 4 
Javier Ruiz 1 
Email address for contact author: margarita.rincon@icman.csic.es 
1 Department of Coastal Ecology and Management 
Instituto de Ciencias Marinas de Andalucfa (ICMAN) 
Consejo Superior de Investigaciones Cientfficas (CSIC) 
Campus Universitario Rfo San Pedro 
11519 Puerto Real, Cadiz, Spain 
2 Institut Mediterrani d'Estudis Avan<;ats (IMEDEA) 
CSIC/Universitat de les Illes Balears (UIB) 
Carrer de Miquel Marques 21 
07190 Esporles, Balearic Islands, Spain 
3 Fisheries and Environmental Management Group 
Department of Environmental Sciences 
University of Helsinki 
P.O Box 65 
Viikinkaari 1 
00014 Helsinki, Finland 
4 Sustainable Resources Directorate 
Joint Research Centre 
European Commission 
Via Enrico Fermi 2749 
21027 Ispra, Italy 
The physical and trophic environ¬ 
ment affects fish stocks and landings 
(Lloret et ah, 2001; Erzini, 2005), 
particularly for short-lived small pe¬ 
lagic species (Nakata et ah, 2000; 
Guisande et ah, 2004; Basilone et 
ah, 2006; Lindegren et ah, 2013). 
This effect is observed at differ¬ 
ent time scales (Freon et ah, 2005). 
Short-term synoptic events that last 
a few days and affect a relatively 
large area affect mostly the early life 
stages of fish. For small pelagic fish, 
stock dynamics are often more de¬ 
pendent on recruitment failure from 
mortality at early life stages than on 
variations in fishing effort (Cingolani 
et ah, 1996; Dimmlich et ah, 2004). 
Variability and instability character¬ 
ize the dynamics of small pelagic fish 
(Freon et ah, 2005). Their position in 
the food web and the prominent role 
of recruitment in population dynam¬ 
ics partly explain the aforementioned 
dynamics. The inclusion of environ¬ 
mental drivers in predictive recruit¬ 
ment models for these (and other) 
species has been advocated in the 
past and is increasing (Barange 1 ; 
1 Barange, M. 2001. Report of the first 
meeting of the SPACC/IOC study group 
on “use of environmental indices in the 
management of pelagic fish populations” 
