| SPEEDING FINES AND ONE-WAY ROADS: OR WHY FISH NEED A TICKET TO RECRUITMENT SUCCESS |
| BARANGE, M. (1); Brodeur, R.(2); Köster, F. (3); van der Lingen, C. (4); Möllmann, C. (3); Petitgas, P. (5); Planque, B. (5); Roy, C. (6); Sundby, S (7); Vikebø, F. (7). (1)GLOBEC, PML, Prospect Place, Plymouth PL1 3DH, UK. M.barange@pml.ac.uk; (2) NFSC-NOAA, USA; (3) DFM, Denmark; (4) MCM, South Africa; (5) IFREMER, France; (6) IRD, France; (7) IMR, Norway. |
| Fish recruitment relies on a number of positive circumstances: a reasonable parental stock, adequate spawning at the right time and in the right place, sufficient conditions for growth, etc. In most cases success is determined by specific behavioural adaptations to prevailing physical forces. For example, in the Benguela upwelling region anchovy and sardine spawn in the stratified waters south of the African continent and depend on a jet current to transport their spawning products to the food-rich, upwelling-dominated recruitment areas. In the Baltic the relative success of cod and sprat recruitment is associated with fluxes between the North and Baltic Seas, both directly by providing adequate spawning volume and indirectly through food-web dynamics. In the Bay of Biscay, the recruitment success of anchovy is determined by coastal upwelling intensity in spring and early summer and stratification breakdown from late summer onwards. Off Norway, the distribution of Arcto-Norwegian cod recruits responds to temperature fields and prevailing transport processes between the Norwegian and Barents Sea. Despite these evolutionary adaptations recruitment is highly variable, particularly in pelagic species, reflecting the difficulties involved in matching behavioural processes to highly dynamic and variable physical forces. Understanding what works and does not work in the recruitment of these species provides us with generic tools to explore potential climate change impacts. This presentation will explore some of these impacts, concluding how having the right ticket for the right ride is an essential process of to ensure recruitment success. |
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