Responses of the spiny lobster Palinurus elephas to 20 years of protection in a temperate marine reserve

Abstract

The European spiny lobster Palinurus elephas has been unfished in the Columbretes Islands MPA (Western Mediterranean) since its creation in 1990. The MPA harbours 44 km2 of lobster coraligenous and maërl grounds, largely closed to all extractive activities. Monitoring started 7 years after MPA creation and its first aim was to assess the status of P. elephas in the MPA relative to areas continued to be fished. This intitial spatial comparison indicated that lobster density and relative egg production was 5—20 times greater in the MPA than in fished areas. Continued monitoring up to year 20 of protection (2010) provided a unique oportunity to assess the evolution of abundance and demography in the unfished population for a period close to the life span of the species. Tag-recapture experiments allowed to document and measure the amount of spillover from the MPA being harvested by the adjacent commercial fishery. We estimated a net benefit of spillover from the Columbretes MPA to the regional lobster fishery of 11% of the annual catch, which compared to a 6 times greater egg production supports the contention that egg and larval export have far greater potential than spillover to benefit exploited populations. Marine protected areas that effectively rebuild biomass of exploited species within their boundaries are expected to benefit local fisheries through biomass spillover and export of eggs and larvae. The Columbretes MPA lobster study is unique in that has evaluated both of these effects