Uncertainty in stock assessments, spatial distribution and habitat modelling of two small pelagic fish species, sardine (Sardina pilchardus) and anchovy (Engraulis encrasicolus), in the Mediterranean from late autumn spanish acoustic surveys

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A la meva família, als meus amics, i a tots els que d’alguna manera han fet aquest treball posible

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Agradecimientos/Agraïments

Esta tesis no habría sido posible sin la participación de tanta gente que de alguna manera han aportado su granito de arena tanto al trabajo y a la persona que soy. Así que estas líneas son para agradecerles el haber estado en algún momento ahí, en mi camino.

En primer lugar, cómo no darle las gracias a mi madre. Una GRAN persona en mayúsculas a la que además de la vida le debo tantas cosas!! Entre ellas, el haber podido introducirme en el mundo de la investigación (con sus más y sus menos pero siempre bonita) y haber conocido a tanta gente extraordinaria que han formado o forman parte de esta historia.

A mis compañeras/os de trabajo, de café y a mis amigas/os de mis primeros años en el mundo científico en el IMEDEA, a los que guardo tanto cariño. Gracias a todas/os por tantos momentos, gracias por haber estado ahí. Besos a todas/os, os deseo lo mejor!

También quiero darle las gracias al grupo de acústica al completo del Centro Oceanográfico de las Islas Baleares – Instituto Español de Oceanografía (COB-IEO). En especial, a Juan Miquel y a Dolors por su trabajo como técnicos de acústica, sin los cuales nada habría sido posible. Agradezco a Juan, con especial cariño, sus lecciones de teoría acústica durante mi primera campaña de acústica, sin las cuales el McLennan & Simmonds, piedra filosofal de la acústica, habría sido un hueso duro de roer!!! A Marilin, como directora de tesis y jefa de grupo, por su paciencia, sus consejos y su apoyo.

Compartir siempre es enriquecedor. Así pues, gracias a los acústicos y geoestadísticos de diferentes países con los que me topado en reuniones internacionales el haber podido intercambiar quebraderos de cabeza en momentos difíciles y me han hecho descubrir que había alguien ahí fuera con “dilemas” parecidos a los míos. A Marco Barra, Roberto Gramolini, Marianna Giannoulaki, Fabio Campanella…Un gracias enorme a Marianna y a su equipo y colaboradores en Creta, por su hospitalidad y su colaboración (ευχαριστώ!

#efaristó!). A Pierre Petitgas, por ser un referente en geoestadística. Gracias al IEO por haber hecho todo esto posible!

Quiero agradecer a las tripulantas/es, científicas/os y marineras/os que han participado y posibilitado las campañas ECOMED, en las cuales he basado mi trabajo. No quiero olvidarme del equipo de administración del COB, duro y no siempre reconocido trabajo el suyo pero indispensable para que todo esto funcione.

Esto no habría sido lo mismo sin mis compañeras/os de viaje, en el sentido más literal y en el más literario de la palabra. Gracias por las pequeñas y a las grandes enseñanzas. A mis compañeras/os y amigas/os del COB-IEO, a las horas de cuerda, a las charlas de café y diversión.Gracias por demostrarme vuestro apoyo en tantos momentos y por vuestros consejos. A todas las personas que han formado parte de las horas de diversión y de los momentos de estrés. A mis compañeras/os de despacho, del presente y del pasado y sobre todo a las del presente por soportar mis últimos y más duros meses. Gracias por vuestra inconmensurable paciencia.

I, per suposat, a sa meva família, a sa pradina, a mon pare, en es meu germà, a sa meva germana, i a en Lleonet i a en Felipe, per estar al meu costat en tot moment. Sense oblidar a meva familia peninsular-illenca, n’Ainarona, na Chispa, na Loa i en Jesús, sempre aprop! A ses amigues i germanes d’adopció, na Marga i na Mar, n’Aina i n’Antònia. No fa falta que vos digui quant vos estim. Gràcies a tots!

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A Esporles, es rentadors des Jonquet y Santa Catalina, por diversos y entrelazados motivos. A Santa Bárbara y a las latas de sardina.

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Derived publications

Chapters 2 to 5 presented in this thesis have been partially published or submitted for publishing in the form of scientific papers. In particular,

Chapter 2 is based on the paper: “Tugores, M.P., Iglesias, M., Díaz, N., Oñate, D., Miquel, J. and Giráldez, A. 2010. Latitudinal and interannual distribution of the European anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) in the western Mediterranean, and sampling uncertainty in abundance estimates. ICES Journal of Marine Science, 67: 1574-1586”

A reduced version of Chapter 3 has been sent for publication as: “Tugores, M.P., Iglesias, M., Oñate, D. and Miquel, J. Spatial distribution, sampling precision and survey design optimization with non-normal variables: the case of anchovy (Engraulis encrasicolus) recruitment in the Spanish Mediterranean waters. Progress in Oceanography. Submitted”

Chapter 4 have been partially published within a broader paper, co-authored with people from other Mediterranean countries and including data from these other countries as: “Tugores, M.P., Giannoulaki, M., Iglesias, M., Bonanno, A., Ticina, V., Leonori, I., Machias, A., Tsagarakis, K., Díaz, N., Giráldez, A., Patti, B., De Felice, A., Basilone, G., and Valavanis, V. 2011. Habitat suitability modeling for sardine Sardina pilchardus in a highly diverse ecosystem: the Mediterranean Sea. Marine Ecology Progress Series, 443: 181-205”

Chapter 5 have as well been partially published within a broader paper, co- authored with people from other Mediterranean countries and including data from these other countries as: “Giannoulaki, M., Iglesias, M., Tugores, M.P., Bonanno, A., Patti, B., De Felice, A., Leonori, I., Bigot, J.L., Ticina, V., Pyrounaki, M.M., Tsagarakis, K., Machias, A., Somarakis, S., Schismenou, E., Quinci, E., Basilone, G., Cuttitta, A., Campanella, F., Miquel, J., Oñate, D., Roos, D., and Valavanis, V. 2013.

Characterizing the potential habitat of European anchovy Engraulis encrasicolus in the Mediterranean Sea, at different life stages. Fisheries Oceanography, 22 (2): 69- 89”

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Llist of acronyms and abreviations

AIC - Akaike’s Information Criterion ANOVA - Analysis Of Variance AUC - Area Under the ROC

CFP – European Common Fisheries Policy CHLA - sea surface chlorophyll concentration CI – confidence interval

CUFES – Continuous Underway Fish Egg Sampler CV – Coefficient of Variation

DSP – Digital Signal Processing

EDSU – Elementary Distance Sampling Unit EU – European Union

EVA – Estimation of the VAriance

FAO – Food and Agriculture Organisation of the United States GAMs - Generalised Additive Models

GCV - Generalized Cross Validation

GFCM - General Fisheries Commision for the Mediterranean Sea GLOBEC - Global Ocean Ecosystem Dynamics programme

GSA - Mediterranean Geographical Subarea I2D – intrinsic geostatistics in 2 dimensions

ICES – International Council for the Exploration of the Sea IEO – Instituto Español de Oceanografía

MDT - maximization of the specificity-sensitivity sum MPA – Marine Protected Area

NASC – Nautical Area Scatering Coefficient NC – Northern Current

NS – Northern subarea (defined in Fig. 2.1) PAR - photosynthetically active radiation PDF – probability distribution function PRV – prevalence

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PSH – potential spawning habitat

ROC - Receiver Operating Characteristic curve RSH - realised spawning habitat

SGMED - Study Group on Mediterranean Fisheries SLA - sea level anomaly

SS - Southern subarea (defined in Fig. 2.1) SSS - sea surface salinity

SST - sea surface temperature

T1D – transitive geostatistics in 1 dimension TS – target strength

Tukey HSD - Tukey’s Honestly Significant Difference test

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Summary/Resumen/Resum

Summary

Small pelagic fish are species that live in the water column and have little relationship with the sea bottom. During the day they may form schools with feeding, defence or energetic efficiency purposes and disperse during the night. The importance of small pelagic fishes within the marine ecosystem rely in the proportion of biomass they represent and the clue function they develop as intermediate links in the energy transfer between lower and upper levels of the trophic chain. Their populations are particularly sensitive to environmental fluctuations (Cole and McGlade, 1998; Lloret et al., 2004) and frequently highly exploited by commercial fisheries. These may occasionally collapse the stocks affecting both the marine ecosystem and the fisheries they sustain.

In the Mediterranean, almost 50% of the total annual landings are attributable to small pelagic fishes (Lleonart and Maynou, 2003). In the Western Mediterranean Sea, sardine (Sardina pilchardus) and anchovy (Engraulis encrasicolus) are the two most important species in terms of landed biomass and commercial interest (Lleonart and Maynou, 2003). Despite their importance little is known about the spatial distribution of these stocks or about the relationship between the spatial distribution and environmental variables.

Since the ‘90s acoustic surveys are annually performed in the Spanish Mediterranean continental shelf in late autumn (Abad et al., 1998 a,b) coinciding with anchovy’s recruitment and the beginning of the spawning season for sardine (Abad and Giráldez, 1993; Giráldez and Abad, 1995). Although the main goal of these surveys is to estimate abundance and biomass of sardine and anchovy, data about the whole pelagic community has also been gathered. Furthermore, in the last decade it was detected an increasing appearance of other small and medium-sized pelagic species and the application of a multi-species approach to Mediterranean fisheries assessment was advised (Lleonart and Maynou, 2003).

The present work is structured in two sections. The first section of the work will analyse the spatial distribution (1D and 2D) of sardine and anchovy by means of geostatistical techniques, both transitive and intrinsic methods (Matheron, 1969).

Special attention will be paid to the estimation of the uncertainty associated to abundance estimations and, concretely, the uncertainty caused by sampling scheme which is thought to be one of the main contributors to random error (ICES, 1998).

The second section will explore the environmental factors that drive the presence or absence of anchovy and sardine in late autumn. Satellite environmental data as sea surface temperature, salinity, chlorophyll-a, photosintethic active radiation, sea level anomalies or bottom depth will be related to the presence-absence of sardine and anchovy stocks through Generalised Additive Models (GAM) to try to depict the relationships that may be found between both (Bellido et al., 2008; Giannoulaki et al., 2008). The spawning area of sardine will also be studied in order to model the presence-absence of sardine eggs and try to understand the evolution of their stocks.

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Resumen

Los pequeños peces pelágicos son especies que viven en la columna de agua y que tienen poca relación con el fondo marino. Durante el día forman bancos de peces con el objetivo de alimentarse, defenderse de potenciales depredadores o por motivos de eficiencia energética, dispersándose durante la noche. La importancia de los pequeños pelágicos en el ecosistema marino radica en la proporción de biomasa que representan y en la función clave que desempeñan como eslabones intermedios, transfiriendo energía entre los niveles tróficos inferiores y superiores de la cadena trófica. Sus poblaciones son particularmente sensibles a las fluctuaciones ambientales (Cole and McGlade, 1998; Lloret et al., 2004) y frecuentemente se encuentran en un régimen de explotación elevado por parte de las pesquerías comerciales. Esto puede comportar de manera ocasional el colapso de sus poblaciones explotables, afectando al ecosistema marino y a las pesquerías que las mantinen.

Casi el 50% del total de la biomssa anual desembarcada en los puertos del Mediterráneo provienen de los pequeños peces pelágicos (Lleonart and Maynou, 2003). En el Mediterráneo Occidental, la sardina (Sardina pilchardus) y el boquerón (Engraulis encrasicolus) son las dos especies más importantes, tanto en términos de biomasa como capturada como por su interés comercial (Lleonart and Maynou, 2003).

A pesar de su importancia, la distribución espacial de las poblaciones explotables es poco conocida así como también lo es la relación de la distribución espacial con los parámetros ambientales.

Desde principios de los años 90, se llevan a cabo campañas acústica en la plataforma continental española del Mediterráneo a finales de otoño (Abad et al., 1998 a,b), coincidiendo con el reclutamiento de la anchoa y la época de puesta de la sardina (Abad and Giráldez, 1993; Giráldez and Abad, 1995). A pesar de que el principal objetivo de estas campañas es la estimación de la abundancia y de la biomas de la sardina y el boquerón, datos de la comunidad pelágica en conjunto también se recogen periódicamente. Además, a lo largo de la última década se ha detectado una aparición incremental de otras especies de pequeños y medianos pelágicos y por tanto, se aconsejó la aplicación de un enfoque multiespecífo en la evaluación de pesquerías del Mediterráneo (Lleonart and Maynou, 2003).

El presente trabajo se estructura en dos seciones. La primera sección del trabajo analizará la distribución espacial (1D y 2D) de la sardina y el boquerón por medio de técnicas geoestadísticas, tanto transitivas como intrínsecas (Matheron, 1969). Se prestará especial atención a la incertidumbre asociasda a las estimaciones de abundancia y, concretamente, a la incertidumbre asociada al diseño de muestro que se considera uno de los factores que contribuyen con mayor intensidad al error aleatorio (ICES, 1998).

La segunda sección explorará los factores ambientales que condicioinan la presencia o ausencia de sardina y boquerón a finales de otoño. Datos ambientales obtenidos de satélite, como la temperatura superficial del mar, la salinidad, clorofila, radiación fotosintéticamente activa, anomalía del nivel del mar y la profundidad del fondo marino se relacionarán con la presencia-ausencia de las poblaciones explotables de sardina y boquerón mediante modelos aditivos generalizados (GAM, del acrónimo inglés) para determinar las relaciones existentes (Bellido et al., 2008; Giannoulaki et al., 2008). El hábitat de la puesta de sardina será igualmente estudiada para modelar la presencia-ausencia de huevos de sardina e intentar entender la evolución de las especies explotables.

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Resum

Els petits peixos pelàgics són espècies de peixos que viuen a la columna d’aigua i que tenen poca relació amb el fons marí. Durant el dia formen bancs de peixos amb l’objectiu alimentar-se, defensar-se en front potencial depredadors o per eficiència energètica, dispersant-se durant la nit. La importància dels petits pelàgics a l’ecosistema marí radica en la proporció de biomassa que representen i en la funció clau que exerceixen com esglaons intermedis, transferint energia entre les nivells inferiors i superiors de la cadena tròfica. Les seves poblacions són particularment sensibles a les fluctuacions ambientals (Cole and McGlade, 1998; Lloret et al., 2004) i freqüentment es troben baix un règim d’explotació elevat per part de les pesqueres comercials. Això pot comportar de manera ocasional el col·lapse de les seves poblacions explotables, afectant a l’ecosistema marí i a les pesqueries que sostenen.

Gairebé el 50% del total de la biomassa anual desembarcada als ports del Mediterrani prové dels petits peixos pelàgics (Lleonart and Maynou, 2003). Al Mediterrani Occidental, la sardina (Sardina pilchardus) i l’aladroc (Engraulis encrasicolus) són les dues espècies més importants, tant en termes de biomassa capturada com pel seu interès comercial (Lleonart and Maynou, 2003). Malgrat la seva importància, la distribució espaial de les poblacions explotables és poca coneguda així com també ho és la relació d’aquesta distribució espaial amb variables ambientals.

D’ençà de principis dels anys 90, es duen a terme campanyes acústiques a la plataforma continental del Mediterrani espanyol a finals de la tardor (Abad et al., 1998 a,b), coincidint amb el reclutament de l’aladroc i amb l’època de posta de la sardina (Abad and Giráldez, 1993; Giráldez and Abad, 1995). Tot i que el principal objectiu d’aquestes campanyes és l’estimació de l’abundància i de la biomassa de la sardina i l’aladroc, dades del conjunt de la comunitat pelágica també es recolleixen.

A més a més, al llarg de la darrera dècada s’ha detectat una aparició incremental d’altres espècies de petits i mitjans pelàgics i per tant, es va aconsellar l’aplicació d’un enfoc multiespecífic a l’avaluació de les pesqueres del Mediterrani (Lleonart and Maynou, 2003).

El present treball s’estructura en dues seccions principals. La primera secció del treball analitzarà la distribució espaial (1D i 2D) de la sardina i l’aladroc per mitjà de tècniques geoestadístiques, tant transitives com intrínseques (Matheron, 1969). Es prestarà especial atenció a la incerteza associada a les estimacions d’abundància i, concretament, a la incertesa originada pel disseny de mostreig que és considerat un dels factors que contribueixen amb més intensitat a l’error aleatori (ICES, 1998).

La segona secció explorarà els factors ambientals que condicionen la presència o absència de sardina i aladroc a finals de tardor. Dades ambientals obtingudes de satèl·lit, com la temperatura superficial de la mar, la salinitat, clorofil·la, radiació fotosintèticament activa, anomalies del nivell de la mar i la profunditat del fons marí es relacionaran amb la presència-absència de les poblacions explotables de sardina i aladroc mitjançant models additius generalitzats (GAM, de l’acrònim anglès) per determinar les relacions existents (Bellido et al., 2008; Giannoulaki et al., 2008).

L’hàbitat de la posta de la sardina serà igualment estudiada per tal de modelar la presència-absència d’ous de sardina i intentar entendre l’evolució de les seves poblacions explotables.

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Chapter 1. General Introduction

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ies might b ecies origina

which migh e stock ass

s more and offer some

ng approac might be u pecies, for i wo small fis European a y represent 009 (FAO, 2 he most im Lleonart an

iners in the

and anchov panish Med

a to estima esolution en s under stud

anagement t al., 2004 or any post ability (or p excuse the

(Pauly et a ck assessme erest in the rnational C stimates ca opulation. O

abundance d.

ociated erro influence o nservation b cies is foun osed areas cies that c h environm 2007; Giann

f measures eloped. Ch at might be

ed to be kn tially woul

be useful in ated by ch ht be drive sessment a d more inte insight in ch. Further seful to ide instance by sh pelagic anchovy (E ted 32-44%

2013). In th mportant sp nd Maynou,

e area (Per

vy are the m iterranean

ate abundan nabling as w

dy.

t has been 4); notwith terior atte precision) o e implemen

al., 2002).

ent is crucia e internatio Council of an become Obviously, and bioma

ors, the kn of environm

biology and nd is crucia . Acoustic can be app mental data

noulaki et a

s and pol anges in th e driven by nown in ord

d facilitate

n order to p hanges in th en by the c and the es eresting. P this topic;

, gaining k entify area y establishin species Eu Engraulis e of the tota he Western

pecies in t 2003) bei rtierra and

most abund continenta

nce and bio well high qu

n given gro standing si mpt to ma of single-sp tation of fi Thus, rout al to accom onal comm

the Sea (I clue to pro the intere ass estimat

nowledge o ental facto manageme al to design surveys pr plied to sp a, to mode al., 2011; Be

icies for e distributi y environm der to be ab e to achieve

predict pote he habitat climate cha stimation o Potential ha in spite o knowledge a

as that cou ng MPAs.

uropean sa encrasicolus al landings i

Mediterran terms of la

ing anchovy Lleonart,

dant fish sp al shelf anc

omass uality

owing ingle- anage pecies ishing tinely mplish munity CES).

operly est in

es by

of the ors on ent of n, for ovide patial el the

ellido

stock ion of mental ble to e the

ential (e.g.

ange.

of its abitat of the about ld be

ardine s L.) n the nean, anded y the 1996;

pecies chovy

(27)

and acou shelf anch comm 2010 sligh addit anch imma 12.7 (Pert

estim Span their autu

1.2 and

Span Strai is na the wide (33 inden 8,513

Curre outfl south coast Stron The river domi Gibra with eddie resul (Cha most 1999

thou 100-2 river upwe

sardine re ustic survey f of the Ba hovy repres munity esti 0). Their sto

t recover in tion, there hovy’s recru ature fish ( cm for ma tierra and L The prese mates of th nish contine r habitat to

mn (mid No

The Sp d hydrog

The study nish Medite

t of Gibralt arrow, often

Strait of G ens till the

nm). In th nted by su 3 nm² (29 1 The circul ent (NC) a c low of large hwest (Fon t, and eve ng northerl

wide conti rs further c

inated by altar. The s mesoscale es (Estrada lting in a mpalbert, t western gy 9).

The photic ght to be t 200 m dep rine outflow

elling from

presented ys between

alearic bas sented 65- mated in th ocks have n 2001 and e is incre uitment sin

Pertierra a ales and fem Lleonart, 19 ent study f hese two s ental shelf, o the enviro ovember-mi

panish M graphica

area is loca rranean co tar and the n less than Gibraltar an

surrounding e Catalan ubmarine ca

99 Km²).

lation is do cyclonic alo e rivers. Th t et al., 19 entually rea y winds, ty inental she characteris

less saline surface Atla

features, s a, 1996) gen

local enric 1997). Two yre is quasi

c zone, or v he most pro pth. Moreo ws and als the sea bo

between 3 2003 and 2 in (Norther -92 % of t he acoustic

been decli 2003 (Girá asing conc nce an imp nd Lleonart males respe 996).

focus the species pro , analyse t onmental ch

id Decembe

Mediter al charac

ated in the ontinental s Spanish-Fr 6 nautical nd the Cap gs of the Eb coast, con anyons. Th

minated by ong-slope fr he NC flow 988), carry aches the ypical in wi elf and fres e the area Atlantic w antic water such as tur nerating up chment of o anticyclon

i permanen

volume of t oductive in over, prima so in place ottom to th

38 and 67 2009 (unpu rn Spanish the small surveys in ning since áldez et al.

cern about portant fra

t, 1996). Siz ectively wh

attention t ovided by l the spatial haracteristic

er).

rranean cteristics

Western M shelf along rench borde l miles (nm pe of Palos bro River, w ntinental sh he total are

y the entra ront in the ws along the

ying water f Alboran Se inter, may sh-water ru a. In the A water ente

rs, although bulent mixi pwelling alo

nutrients a nic gyres a nt while the

the water c seas and o ary product es where w he sea surfa

% of the blished dat Mediterran

and medi the period

the 90s, a ., 2006a,b;

t the poss ction of th ze at first m hile the min

to the pre late autum structure

cs present

waters:

s

Mediterrane the Iberia er (Figure 1 m, 1 nautica s. Northwa where the helf is nar ea of the

nce of the north-west e continent from the G ea (Millot, intensify t un-off from Alboran Sea ring the ba h relatively

ing, anticyc ong the na and primar re generate e eastern on

column whe oceans and

tion is high water circu ace. In Wes

estimated ta, IEO). In nean water um sized 2003-2006 lthough an Palomera sible over- he fishing maturity oc nimum land

ecision of t mn acoustic

of their st in the samp

geomo

an basin an an Peninsul

.1a). The c al mile = 18 ards, the co

maximum w row (less t continenta

Atlantic wa tern Medite tal shelf fro Gulf of Lion

1999; Font the NC (Pin m the Rhon a the wate asin throug y nutrient-p

clonic gyres rrow contin ry producti ed in the A ne is more

ere the ligh is generally her in coa ulation gen stern Medit

biomass in the contin rs), sardine pelagic sp (Tugores e chovy show et al., 2007 -exploitatio

effort relie ccurs at 12.

ding size is

the abunda surveys in ocks and r pled area in

orpholog

nd comprise a, between continental

852 m) bet ontinental width is rea

than < 14 l shelf is a

aters, the N erranean an

om northea n to the Ca t et al., 1 not et al. 2 ne and the er circulati gh the Stra poor, are re

s, meander nental shel ion in the Alboran Sea variable (M

ht penetrat y between 0 astal areas

nerates nut terranean,

n the nental

e and pecies et al., wed a

7). In on of

es on 5 and 9 cm

ances n the relate n late

gical

es the n the shelf

ween shelf ached nm), about

North d the ast to atalan 988).

2002).

Ebro on is ait of elated

rs and f and area a, the Millot,

tes, is 0 and with trient these

(28)

areas and E conc prod

Figur study show betw 2007)

s of increa Ebro, and i centration

uction (Figu

re 1.1. Span y area (NC: N ing more va een January ). http://rea

ased produc n the Albor can be us ure 1.1b).

nish Mediterr Northern cur

ariable curre y 2003 and D ason.gsfc.na

ctivity are ran Sea due sed as a p

ranean wate rrent; solid li ents) and (b December 20 sa.gov/Giova

found in th e to water m proxy to r

ers: (above) ines showing bottom) me 008 from Se anni)

he vicinity masses circu

reveal the

main wate g the most st an chloroph eaWiFS satel

of the mai ulation. Me areas of

er circulation table circula hyll-a concen

llite data (A

in rivers, R an chloroph

higher pri

n patterns i ation; dashed

ntration (mg Acker & Lept

Rhône hyll-a imary

in the d lines

g m^-3) toukh,

(29)

1.3 ( En biol

in la 2005 10 an funct biolo large sensi sensi al., 2 are f funct 2002 rigen North anch incre GLOB Geog

bathy found the b distr Medi as in sardi found

Figur Medit (Modi

Sardin ngraulis e logy and

Pelagic fis rge schools 5). Small pe

nd 30 cm, tion as bott ogy of thes e quantitie ible to env ible to envi 2004). Abru frequent an tioning of 2), triggerin ns) in the 70

hern Spain, hovy, their

ease in tem BEC (Barang graphical an European ymetric dis d in the No both hemis ibuted in terranean the Northe ine is betw

d up to 400 (a)

re 1.2. Geog terranean:

ified from Fi

ne (Sar encrasico d geogra

shes are kn s during the elagic fishes

are commo tom-up ene se species, es of eggs vironmental ironmental upt increase

nd may aff the ecosys ng the colla 0s or, more , where the populations mperature ge et al., 2 nd bathyme

sardine (S stribution t orthern hem

spheres, fro the Easter they are w ern Aegean ween 25 and 0 m depth (

graphical dis (a) sardine, ishbase; sour

rdina p olus L.):

aphical d

own to per e day and re

s, consider only foragin ergy transfe i.e. short over exte l changes ( variability es and dec fect both t stem (Cury apse of the e recently, e fishery wa

s have been by the G 010).

etric distrib ardina pilc than Europe misphere fro om Iceland rn Atlantic widespread

Sea (Figure d 100 m de

Schneider,

stribution of , Sardina p rce: Whitehe

pilchardu notes a distribut

rform daily emaining di ing as such ng species o erors in the

life-span a ended area (Bakun, 199 and change reases of t he fisherie et al., 20 fisheries, European a as closed be n recently r

lobal Ocea

bution chardus) ha

ean anchov om Norway and Norw c and the

through the e 1.2). The epth (White

1990).

f the main s pilchardus a ead et al., 1

us Wal about th tion

vertical mi isperse dur h species w of high eco trophic cha and reprod as), makes 96). Their es (Cole an he populati s they sust 000; Shanno e.g. the Pe anchovy (En

etween 200 recognised an Ecosyste

as a less e vy (Engrauli y to Senega way to Sout Mediterran e Western

bathymetr ehead, 1990

(b

small pelagic nd (b) anc 988 and Whi

lb.) and he speci

igrations, u ing the nigh ith adults’

ological valu ain (Cury et uctive stra these spe recruitmen d McGlade, ions of sma tain and th on et al., eruvean anc ngraulis enc

06 and 2010 as vulnerab em Dynam

extended ge is encrasico l while anc h Africa. B nean (Figur and Centra ric distribut 0) whereas

b)

c fish specie hovy, Engra itehead, 199

d anch ies ecolo

usually gath ht (Fréon e length bet ue, due to t al., 2000) ategy (prod ecies espe t is particu , 1998; Llor all pelagic f he structure 2000; Dask chovy (Eng crasicolus) i 0. In the ca ble to long ics program

eographica olus). Sardi chovy is fou Both specie re 1.2). In al Basins as

tion of Euro anchovy ca

es in the We aulis encras 90).

hovy ogy,

hering et al., ween their . The ucing cially ularly ret et fishes e and kalov,

raulis n the ase of term mme,

l and ine is und in es are n the s well opean an be

estern sicolus

(30)

Spaw

Febr abun Oliva conc Cont et a Octo temp 1996

proce globa nutri wind refer and Estra relat proxi and even (5-41 2001 Matu

(mai Medi there 15.00 cm in varie el al for m (Girá Feed

phyto anch and A et a diet like capa feed sardi al., 2

wning Sardine sp uary (Palom ndance of s ar et al., centration o trarily, anch al., 2010).

ober with perature be 6).

The spaw esses. In th al scale an ients from ds and thus rences ther is related ada, 1996; A ted to the

imity of riv Palomera, ntually ente

1ppt); cont ).

urity The lengt nly age 0 g terranean ein). In the 0 cm in the n the Malag es between ., 1996). In males and f áldez and A ding

Small pe oplankton a hovy is know Azov Sea it l., 2007 an preying on diatoms (C able of sw

ing for bigg ines over th 2004; Garri

pawns from mera and spawners a 2001). Sp of sardine hovy spawn In the We a peak in etween 15º

wning of sa he Western d is relate the bottom it is though rein). Durin

to river ru Arnau et al ese areas,

vers, even 1996; Oliva er lagoons,

trarily, sard

h at first m roups and 1

Sea than i e Spanish M e coasts of ga Bay, Albo

5.6 and 13 n the Weste emales resp Abad, 1995;

elagic fishe and/or mic wn as a zoo t has also be nd referenc

zooplankto Costalago a witching be

ger preys.

he world, w do et al., 2

m autumn Olivar, 199 at sea surfa pawning oc eggs at de ns in the wa estern Medi summer, º and 22ºC

ardine and n Mediterra ed to vertic m to the e ht to favour g summer w unoff, front

., 2004). An especially in regions ar et al., 2

estuaries o dine larvae

maturity (L 1) across its in the Atla Mediterrane Valencia (A oran Sea (A 3.7 cm acro ern Mediterr

pectively, w Pertierra a

es are p cro- and me oplanktivoro

een found t ces therein on (e.g. cla and Palome tween filte This ability was only re 2007, 2008;

to spring 96; Olivar ace tempe ccurs main epths below armest mon

iterranean in June-A

(Palomera

d anchovy anean, wat cal mixing,

euphotic zo r sardine re

water enric tal systems nchovy spaw to river o

of low disc 2001). Durin

r lakes, as do not to

L50) of sardi s distributio antic Ocean ean waters, Andreu et a Abad and Gi

ss its distri ranean, it w while the m and Lleonar

planktivorou eso-zooplan ous fish mos to feed spo

). Europea adocerans o era, 2014).

er- and pa y, known fo ecently des

Nikoliouda

with a pe et al., 20 ratures of nly in insh w 100 m (O nths (White

anchovy s August, in a, 1989, 19

is associat ter enrichm which pro one. Vertic ecruitment

chment occ s and upwe wning and e outflows a charge (Palo

ng the spaw it has good olerate low

ine ranges on area. L50

n (Silva et , L50 of sar al., 1950) a iráldez, 199 bution area was estimat minimum leg

rt, 1996).

us species nkton (Freó

stly eating oradically o n sardine h or decapods

Both sma articulate-f or long for cribed for akis et al., 2

ak in wint 001, 2003) about 18ºC hore water Olivar et a

head et al.

spawns bet waters wi 992; García

ted to wa ment in win oduces the cal mixing (Palomera curs mainly

ellings (Fon early-life st s anchovy omera, 198 wning seaso d tolerance

salinities

from 10.9

0 is general al., 2006 rdine was e and betwee

93). Regard a (Koranten ted to be 1 gal size in t

s, general ón et al., 2 copepods,

n phytoplan has a more s) as well a

ll pelagic f feeding, us European a European s 2012).

ter, in Jan with maxi C (Oliver, rs with hi l., 2001, 2 , 1988; Tsi ween April ith sea su a and Palom

ater enrich nter occurs

recirculatio is enhance et al., 2007 at a local nt et al., tages are cl spawns in 89, 1992; G on anchovy to low sali

(Sabatés e

cm to 16.

ly smaller i and refere estimated t en 12.6 and ding anchov nk, 1993; Ur

2.5 and 12.

the area is

ly feeding 2005). Euro but in the

nkton (Palo e heterogen as phytoplan fish specie sing partic anchovy an sardine (Bod

nuary- imum 1957;

ghest 2003).

kliras l and urface

mera,

hment at a on of ed by 7 and scale 1987;

losely n the García

y may nities t al.,

8 cm n the ences to be d 13.8 vy, L50

riarte .7 cm 9 cm

g on opean

Black omera neous nkton s are culate nd for de et

(31)

plast (Cho oppo allow 2007 and from inves chara long more Costa

(Garr frequ Sea i nor f et al no f (Palo 2009 in th stom cont there wate stom Palom Ecolo

two impo troph affec

‘bott 2008 prod highl food Migra

winte Cant anch the r summ Sea o

as w

In the Bay ticity than

uvelon et osition to wing them 7). Differenc

sardines in m the Medite

stigated (C acterization as, in term e important

alago and P Although i rido, 2003;

uent in othe intraguild p for sardine l., 2005; an fish eggs a omera et al 9; Garrido a he 1940s an machs (Mass

rol role of s ein). A de er column machs in th mera et al.

ogical role In the Wes small pela ortant role hic chain.

cting upper tom-up’ co 8). In the C uction acc lighting the webs to hi ations

Pelagic fis ering. In th tabrian wat hovy, it ove

rest of the mer (Huret overwinter

However, well as on p

y of Biscay sardine, by al., 2014, anchovy, s to reprodu ces have be n the Atlan

erranean, s Costalago n of sardine ms of prey t in sardine Palomera, 2

in other are

; Bachiller, er areas for predation an

or has bee nd referenc are found l., 2007 and and van der nd 1950s, w

utí and Oliv sardine on a nsity-depen may expla e Mediterr , 2007; Gar in the ecos stern Medit gic species in transferr In the NW r and lower ontrol thus Catalan Sea

cessible to e important gher trophi

shes are kn he Iberian ters to Gal rwinters in year. In t

et al., 200 in the Blac migration peculiaritie

y, it has be y foraging

2015). How sardine can uce under een observe ntic and be

suggesting and Palo e as a phyto y contributi

e’s diet (G 2014).

eas, anchov 2012; Gar r other spec nd canniba

n considere ces therein;

in sardine d reference r Lingen, 20 when ancho ver, 1948;

anchovy’s p ndent mec

in the alm ranean (Val rrido and va system

terranean t s, sardine a

ring energy Mediterran r levels of t

having a h adult anch o anchovy

t role of th ic levels.

nown to pe Peninsula s lician coast the North he Gulf of 07). In the k Sea (Bors is highly va s of the ar

een sugges more offsh wever, labo n retain ve

lower pro ed in the n etween sard

differences omera, 201

oplanktofag ion to carb arrido et a

vy eggs are rrido et al.

cies of the lism have n ed negligibl

; Costalago and anch es therein; B

014 and ref ovy eggs we

Andreu and population

hanism and most absenc

ldés et al.

an der Linge

he bulk of t and anchov y between t nean sardin the trophic higher impa

hovy consu aggregatio his species

erform long sardine mig t (Carrera East of the Vizcaya, a Eastern Me sa et al., 20

ariable and rea where

sted that a hore and a oratory exp ery small ductivity c uber of gill dines from s in their di 14). Neve gous fish ha bon intake, al., 2008a;

frequently ., 2008) an genus Engr not been re le (Tudela a and Palom

ovy stoma Bacha and A ferences th

ere found i d Rodríguez (Palomera e d/or differ ce of fish

, 1987; Ga en, 2014).

the marine vy. As forag

the lower a ne plays a chain, whi act on the

med up to ons (Tudel in channe

g migrations grates in sp and Portei e North Sea anchovy mo editerranea 004).

might dep the species

anchovy has wider rang periments i

preys, i.e.

conditions ( l rakers bet the Atlant iets that sh rtheless, as been put

zooplankt Nikoloudak

found in sa nd although raulis, in the ported neit and Palome mera, 2014).

chs in the Amara, 200 herein). The

in Mediterr z-Roda, 195 et al., 2007 rential dist eggs sardin arcía and P

biomass co ging specie and the upp

‘wasp-wais le anchovy upper leve a 20% of t la and Pa eling energy

s for spawn pring from

iro, 2003).

and move ove from so an, anchovy

pend of the s is found.

s higher tr ge of prey ndicate tha . nanoplan (Garrido et tween anch tic and sar hould furth the tradit into questi on seems t kis et al., 2

ardine’s sto h cannibali e Mediterra ther for anc era, 1997; F . In fact, a e Mediterra 09; Borme e

e only exce ranean sard 51), suggest 7 and refere tribution in ne and anc Palomera,

omes from es, they pla per layers o st’ flow con

would disp els (Coll et the zooplan alomera, 1

y of the pe

ning, feedi Portuguese

In the ca to the Sout outh to nor y from the

e species de In the We

ophic sizes at, in kton, t al., hovies rdines er be tional ion as to be 2012;

mach sm is anean

chovy Fréon lmost anean et al., eption dine’s ting a ences n the

chovy 1996;

these ay an of the ntrol, play a t al., nkton 997), elagic

ng or e and se of th for rth in Azov

ensity estern

(32)

Medi for a they colon popu migr Castr be in acce or an spec Seaso

when 2004 popu 1996 and al., 2 recru Atlan have and r

1.4 asse

asses (1965 pelag acou many the Medi samp spec spati

colum samp abun as in of so echo back (Figu intro and t

terranean l anchovy. Sa are scarc nizing coo ulations of

ations betw ro, 1997). I ndicative of ssibility to n increase

ies (Jorgen onality of l In the We n the popu 4) while an ulation is m 6). Anchovy

intense Nor 2007 and re uitment we ntic, Northe e a positive

references

Echoin essment

Echointegr ssment sinc 5).Nowaday gic fish stoc ustic survey

y internatio Exploration terranean pling at sea

ies. Moreov ial coverage

Echointegr mn by mea pling with ndance whil nformation

ound throug oes generate kscattered e ure 1.3b).

oduction of the establis

large migra ardines wer ce while th oler waters sardine s ween them n the case f migratory the stock in catchabi sen et al., andings and estern Med

lation is m nchovy land mostly com landings ar rth-westerl eferences t ere also fo ern Chile a e influence therein).

ntegratio t: the cas

ration acou ce the late

ys echointe cks worldw ys are annu onal organis n of the Se

(GFCM). Th a, providing ver, they sa

e in a relati ration surv ans of an e

pelagic fis le pelagic t

of the com gh the wate

ed by the o echoes are However, t digital sig shment of s

ation patter re relativel hey can b s (Lluch-B seem to c m and no of anchovy

movement by, e.g. a ility during

2004; Skare d relationsh iterranean, mainly comp dings peak mposed of

re positivel ly winds, at

therein). A ound in o and the Bla on landing

on acous se of the

ustic survey 1970s, afte egration is t wide (e.g. To

ally conduc sms of fishe ea (ICES) a he reasons

g fishery in ample a larg ively short

eys use so echosounde

hing trawls trawls prov mposition of

er, vertical organisms e received, the acquisit gnal proces standard ca

rns have no ly sedentar be highly m Belda et a coexist in significant y, although ts it could a

seasonal re spawning et et al., 20 hips with e , sardine l posed of 1-

in spring-s 1-year old y correlate t one year positive co ther areas ck Sea. In gs but not r

stic surv e Spanish

ys have wid er it was fir

the most ex oresen et a cted to est eries manag

and the Ge for this ar ndependent ge volume o

time span.

und to det er. It is a

s. Acoustic ide biologic f the comm lly from up encountered

amplified a tion of high

sing into s libration m

t been desc ry and rem migratory w

al., 1992) Western M migration

the season also be indi eduction of season like 005).

nvironment andings pe -2 year old summer (Pa

individuals ed with rive

lag (Martín orrelation b

of the w the case o river outflo

veys for h Medit

dely been u rstly propos

xtended me al., 1998; D timate the gement, e.g

eneral Fish re that aco t estimates of the wate

tect organis methodolog c sampling

cal informa munity. The

ward to th d in the sou

and graphic h quality da

cientific ec methods (Foo

cribed eithe ain in refu when they

. Semi-ind Mediterrane along sho nality of the

icating a re school size e occurs wit

tal factors eak in autu

individuals alomera, 1 s (Pertierra erine outflow n et al., 200

between wi world, e.g.

of sardine, w ows (Palome

r pelagic terranean

used for pe ed by Drage ethod for a Dalen et al.

stocks of p g. Internati heries Com oustic surve s of the ab er column a

sms that a gy that com

provides a ation of the e echosoun e bottom, und path (F cally plotte ata was not chosounder ote et al.,

er for sardi gee areas are abun dependent ean with ore (Ramon

e landings m eduction in

e (Fréon, 1 th other pe

umn and sp s (Lloret e

992), when a and Lleo ws, cold wi 08; Palome ind and anc

South-We wind seeme era et al.,

c fish st n survey

elagic fish esund and O assessing m

, 2003). In pelagic fish

ional Counc mmission fo

eys allow d bundance o and allow a

re in the w mbines aco an index of e species as nder emit p and receiv Figure 1.3a) ed as echog

possible ti rs by late 1

1987).

ine or when dant, sub- small n and

might fleet 989), elagic

pring, t al., n the onart,

inters era et chovy estern ed to 2007

tock ys

stock Olsen marine ndeed es by cil for r the direct of the

wide

water oustic f fish s well pulses e the . The grams ll the 1980s

(33)

Late

asses perfo recru the p time analy

proce possi sardi spec mack boop colia they patte broa to an

2005 trans echo oper the 3 fish.

zag t as re Spain consi to ha

late asses (GFC Euro start was t

autumn Sp In the Sp ssment star ormed in la uitment ind population o

, echogram ysing the in

The instal essing allo ible for th ine and anc

ies: Medit kerel (Trac ps), Atlantic as). Their c have also erns might dened to e n ecosystem

A hull-mo 5 and in 2

sducers mo osounder op

ated at 5 f 38 kHz freq

Regarding transects w esources we

n). In 2003 isting of pa ave the sam Abundance autumn S ssment gro CM). With t pean Medit ted being pe

the last wh

panish Medi anish Medi rted to be c ate autumn dex for Euro of European ms were r ntegram ma llation in e owed faster e first tim chovy but o terranean

hurus pictu c mackerel commercial o importan have chan estimate the m approach.

unted split 2006 it wa ounted on perated at frequencies quency wa

the sampli was applied ere devoted 3 the samp

arallel equid me sampling

e and biom panish aco oups of th the aim of terranean w erformed in en late aut

iterranean a iterranean conducted i n (Novembe opean ancho

n sardine (S recorded i anually on a

early 2000s r and mor me to estim

of the acco horse mac uratus), rou (Scomber s interest is ce in the ged (Iglesia e stock of c .

t-beam SIM as substitut n a protru two freque s, i.e. 18, 3 s used to e

ing scheme till 2001. In d to study

ling design distant tran g intensity i mass estima

oustic surve he General

standardisi waters and

n summer 2 tumn acoust

acoustic su waters aco in the 1983 er-Decembe ovy (Engrau Sardina pilc n paper a a paper.

of a scien re accurate mate the a

ompanying ckerel (Tra und sardine scombrus) s lower and ecosystem as et al., 2 coastal pela

RAD EK500 ted by a S uding keel encies, i.e.

38, 70, 120 estimate th

e, a systema n 2002 no a

the Prestig n was chan nsects perp in all the ba ates of sard

eys were Fisheries ing the diff make them 2009 coincid

tic surveys

rveys: histo oustic surv 3. In 1997 th er), with th

ulis encrasic chardus). In and any po

ntific echos e processin abundance

small and achurus m ella (Sardin and Atlanti d also thei m. Further,

2008). Thus agic resour

echosound SIMRAD EK (Figure 1 38 and 12 0 kHz and 2 he density

atic samplin acoustic sur ge oil-spill i ged to a s pendicular t

athymetric dine and a annually su

Commissio ferent acou m comparab

ding with an were perfo

orical insigh veys for pe

hese survey he main aim

colus) and a n 1997, the

osterior es

sounder wi ng of the and bioma medium si mediterrane nella aurita ic chub mac ir abundanc in the la s, the initia rces in an a

der operate K60 echoso

1.4). The 20 kHz, whi

200 kHz, bu and abund

ng design c rvey was pe in Costa da ystematic to the bath strata.

anchovy obt ubmitted t on for the ustic survey

le, another nchovy spaw ormed.

ht

elagic fish ys were ann m of obtain an estimati surveys By stimate im

th digital s data maki ass, not on zed pelagic eus), blue a), bogue (B

ckerel (Sco ces tended ate 2000s al objective attempt to

ed from 19 under with

SIMRAD E ile SIMRAD ut in both dance of pe

consisting o erformed as a Morte (Ga sampling d hymetry in

tained from to the fish e Mediterra ys perform r acoustic s wning. This

stock nually ning a ion of y that mplied

signal ng it nly of c fish

jack Boops omber , but these e was move

90 to h the EK500

EK60 cases elagic

of zig- s long alicia, design order

m the heries anean ed in urvey s year

(34)

Figur from surro

Data

Saav Dece Span perio Girál const to ba EK50 ping cove was tech here

re 1.3. Schem FAO, 1981 oundings of t

a collection Acoustic edra”, 66.7 ember in th nish Mediter od of ancho

ldez, 1993 tant speed athymetry 00 or EK60,

rate, powe ring the en calibrated niques (Foo after) were

me of the em ) and samp he Ebro Rive

data was 7 m length he context rranean wa ovy and wi

; Giráldez of 10 knot (Figure 1.5 working at er 2000 W) ntire contin prior to ea ote et al., e the contin

mission and r ple echogram er mouth (rig

collected (Figure 1.5 of annual ters (ECOM th the spaw and Abad ts along par 5B) and usi

t 38 kHz (7 . Acoustic ental shelf ach survey w

1987). Int nental shelf

reception of m acquired ght).

Fi hu 20

on board 5a) during t surveys of MED). The su wning seaso , 1995). D rallel equid ng a scient º x 7º beam

sampling w between 3 with a 60 m ter-transect f is narrow

Fish sc

sound by an on the 3rd

igure 1.4. Pr ull of the R 006 (image b

the rese he end of N pelagic fis urveys coinc

on for sard Data were distant tran

tific split-b m angle, 1 was perform 30 and 200 mm cooper t distance and 8 nm w

hools

n echosounde d of Decem

rotruding kee R/V Cornide by Joan Miqu

earch vesse November a sh stock as

cided with dine in the continuous sects place beam echos ms pulse le med from s

m depth. T sphere, fol was 4 nau where the c

er (left) (mo mber 2006 i

el installed a e de Saaved uel Batle).

el “Cornid and beginni sessment in the recruit area (Abad sly recorde ed perpendi sounder, SIM ength, maxi

unrise to s The echosou

llowing stan utical miles continental Sea bottom

Water column

odified n the

at the dra in

e de ing of n the tment d and ed at

icular MRAD imum unset under ndard s (nm

shelf r

n