Interannual variability in abundance and length of young coastal cod in the subtidal zone K. L EKVE *, K. E NERSEN †, S. E. E NERSEN †, J. G JØSÆTER † AND N. C HR .S TENSETH *†‡ *Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, PO Box 1050 Blindern, N-0316 Oslo, Norway and †Institute of Marine Research, Flødevigen Marine Research Station, N-4817 His, Norway (Received 23 February 2004, Accepted 1 September 2005) The year-to-year variability of total length and abundance of young cod Gadus morhua in the littoral zone of the Norwegian Skagerrak coast was dominant over spatial variability. The 0 year group cod was slightly larger in exposed areas than in protected areas. Contrary to expectations, the 0 year group cod was less abundant in the protected inner parts of the fjords. Although the natural variability was very large, exposed areas (the skerries) seemed to be the better area for the 0 year group cod, while for the 1 year group cod, no differences in abundance or growth could be identified indicating that they had adopted a mature pattern of movement, utilizing the entire fjord for feeding. Available habitat data indicated that the availability of shelter was a potential cause for the distributional pattern. # 2006 The Fisheries Society of the British Isles Key words: growth; population structure; 0 year group; 1 year group; eelgrass; kelp. INTRODUCTION Populations of coastal cod Gadus morhua L. have their nursery areas in the shallow near-shore littoral zone. Traditionally, the larval (Hjort, 1914) and the juvenile (Campana et al., 1989; Campana, 1996) stages have been considered critical for determining year-class strength of cod (Tveite, 1971; Sundby et al., 1989; Nordeide et al., 1994). Postlarval variability in, e.g. habitat, food avail- ability and predation pressure, however, have been shown to affect growth and post-settlement survival of young cod (Tupper & Boutilier, 1995a, b, c; Anderson & Gregory, 2000; Linehan et al., 2001; Methven et al., 2003). These processes, as well as the transition phase from pelagic to benthic prey (Lommond et al., 1998; Lekve et al., 2002) may be of more importance than previously thought (Sissenwine, 1984; Nordeide et al., 1994). In order to better understand the year-class strength of coastal cod, the post- settlement processes of growth and survival should also be taken into considera- tion. One way of gaining an increased understanding of the post-settlement ‡Author to whom correspondence should be addressed. Tel.: þ47 22 854584 or þ47 22 854400; fax: þ47 22 854001; email: n.c.stenseth@bio.uio.no Journal of Fish Biology (2006) 68, 734–746 doi:10.1111/j.1095-8649.2005.00953.x, available online at http://www.blackwell-synergy.com 734 # 2006 The Fisheries Society of the British Isles