| INFLUENCE OF ENVIRONMENTAL VARIABLES ON LARVAL SUPPLY TO PROTECTED AND NON PROTECTED AREAS ON SOUTHWESTERN MEDITERRANEAN SEA |
| FÉLIX-HACKRADT, F.C., Ecology and Hydrology Department, University of Murcia, Murcia, Spain, 30100, felixhackradtfc@gmail.com; Hackradt, C.W., hackradtcw@um.es; Trevino-Oton, J., jorgeto@um.es; Perez-Ruzafa, A., angelpr@um.es; Garcia-Charton, J., jcharton@um.es. |
| One of the primary objectives of a marine reserve is to maintain populations at sustainable levels by providing more individuals, whether adults or juveniles, to nearby areas. Spillover, or the exportation of adults individuals from marine reserves, has been well documented on literature as the principal outcome of reserve implementation. However, the potential of a MPA acting as a source of larvae to neighbouring populations has been poorly investigated and the spatial and temporal patterns of larval variability is little understood. Aiming understand if there is any effect of protection over larval supply intensity or composition we used light traps to sample larvae inside and outside a protected area at Southwestern Mediterranean sea, along one year period. Additionally information about intensity and direction of winds and currents, besides of light trap working time and moonlight intensity were recorded and compared to samples catch in order to see their influence on spatial and temporal patterns on catches. Also, recruits were surveyed monthly by visual census to investigate the relation between settlement and recruitment intensity. Significant differences on fish community were found at the interaction of months of the year and locality (protected and unprotected area), with higher fish abundance and richness found at the unprotected area, mainly during warmer months. Around 90% of total fish abundance was distributed between 8 and 6 dominant taxa at protected and non protected area, respectively. Multivariate analysis indicate that life history patterns (reproduction period) dictates when fish species may settle, but spatial scale patterns may be further driven by local weather conditions. Many species catches were related to wind intensity or direction, resulting in two major patterns of occurrence. Offshore larvae such as Mullus surmuletus, Pagellus bogaraveo and Sardina pilchardus reaches coastal areas pushed by southerly or easterly winds; whether coastal spawning species such Blenniids and Diplodus annularis did not show any defined pattern, and may be more influenced by small scale conditions, like habitat. Although any significant relationship was found between larvae and recruit abundance, they followed the same spatio-temporal pattern of occurrence indicating that some source of variation may act between both processes, contributing for their uncoupling. These findings indicates that larval supply appears to be mainly stochastic but fish settlement site may be highly influenced by local characteristics such as available habitat, presence of predators or conspecifics, as demonstrated by high correspondence of larvae and recruits at multiple scales. |
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