Seasonal and short spatial patterns in European hake (Merluccius merluccius L.) recruitment process at the Balearic Islands (western Mediterranean): The role of environment on distribution and condition Manuel Hidalgo a, ⁎ , Enric Massutí b , Joan Moranta b , Joan Cartes c , Josep Lloret d , Pere Oliver b , Beatriz Morales-Nin a a CSIC/UIB-Institut Mediterrani d'Estudis Avançats, Miquel Marques 21, 07190 Esporles, Spain b IEO-Centre Oceanogràfic de les Balears, P.O. Box 291, 07080 Mallorca, Spain c Institut de Ciències del Mar (CMIMA-CSIC), Psg. Marítim de la Barceloneta 37-49, Spain d University of Girona, Departament de Ciències Ambientals, Campus Montilivi, 17071 Girona, Spain Received 24 July 2006; received in revised form 21 December 2006; accepted 8 March 2007 Available online 10 January 2008 Abstract This study evaluates the link between the recruitment process of European hake (Merluccius merluccius L.) of the Balearic Islands (western Mediterranean) and the environmental and physiological conditions. Spatio-temporal variation of abundance and condition of fish were evaluated at two locations each with different oceanographic conditions, one in the north (Sóller, SO) and another in the south (Cabrera, CA) of Mallorca Island. Environmental variables explored were hydrography, sediment characteristics, phytoplankton pigment concentration (ppc) and the trophic resources of hake. Individuals were divided in three life stages: recruits, post-recruits and young adults. Hepatosomatic index (HSI), relative condition index (K n ), gonadosomatic index (GSI) and fullness index (FI) were analysed for the three life stages. Recruitment starts in February with the incorporation of smaller hakes, and it can be followed through spring and early summer with a peak in April. However, some spatial heterogeneity in the recruitment process has been found between north and south of the Island. The main pulse of recruitment occurred at a different time in the two areas. Spatial heterogeneity was also consistent with the condition of hake recruits, with higher values of K n and HSI at SO than at CA. Maximum values of K n were found in February at SO and in April at CA, coinciding with the start of the different recruitment pulses to the fishing grounds. Post-recruits and young adults also showed higher condition at SO than at CA. The arrival in spring of the Western Winter Intermediate Waters (WIW) drives the spatial-temporal variation in abundance and condition of hake. Ppc was highly correlated with recruit abundance with a time lag of two months, while for post-recruits the time lag was three months. The observed differences in the condition of hake between areas could be a consequence of the fact that the waters to the north of Mallorca are comparatively more under the seasonal influence of WIW which is formed in more productive areas. Thus, this study characterises the short temporal and spatial variability in the hake recruitment process off the Balearic Available online at www.sciencedirect.com Journal of Marine Systems 71 (2008) 367 – 384 www.elsevier.com/locate/jmarsys ⁎ Corresponding author. E-mail addresses: manuel.hidalgo@uib.es (M. Hidalgo), enric.massuti@ba.ieo.es (E. Massutí), joan.moranta@ba.ieo.es (J. Moranta), jcartes@icm.csic.es (J. Cartes), josep.lloret@udg.es (J. Lloret), pere.oliver@ba.ieo.es (P. Oliver), beatriz.morales@uib.es (B. Morales-Nin). 0924-7963/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.jmarsys.2007.03.005