Assessing interacting impacts of artisanal and recreational fisheries in a small Marine Protected Area (Portofino, NW Mediterranean Sea)

Abstract

Abstract. Marine Protected Areas (MPAs) have spread across the Mediterranean to protect its rich biodiversity and manage human activities for a more sustainable coastal development. Within MPAs, traditional artisanal fishing is competing for space and resources with increasing recreational fishing, likely leading to interacting ecological effects. Such effects are difficult to unravel, given the multispecies character of both fisheries and the complexity of the food webs upon which they both impact. To address these issues, we developed an Ecopath and EcoTroph trophic model for the Portofino MPA case study (NW Mediterranean), in particular to (1) identify keystone species and assess fishing impact on them; (2) analyze the interacting impact of artisanal and recreational fishing on ecosystem biomass and trophic structure; and (3) assess the impact of recreational fishing on artisanal fishing catches. Two high trophic level predator (HTLP) groups coupled important keystone roles with high sensitivity to fishing pressure and should thus be regarded as "sentinels" to be prioritized for the definition of management actions. Recreational fishing had the widest impact on the food web, strongly impacting HTLP. Simulation of different mortality scenarios for each fishery highlighted that the ecosystem is far from its carrying capacity for HTLP. Forbidding recreational fishing allowed a 24% increase in HTLP biomass and benefited artisanal fishing by increased availability of HTLP catches. Artisanal fishing alone could instead be maintained with a moderate impact on the food web. Overall, Ecopath and EcoTroph modeling is a valuable tool to advise MPA management, but it is essential to increase data availability and quality by developing long-term monitoring programs on key species and on artisanal and recreational fishing.

Recreational fisheries in Portofino Marine Protected Area, Italy: Some implications for the management

“…Marine Protected Areas (MPAs) have a significant role in protection of fish communities and the management of the stocks within the designated area (Di Franco et al, 2016;Guidetti et al, 2008): in recent years, much effort has been directed towards investigating the effects of protection on population densities, reduction in juvenile mortality, increases in size, fecundity, biomass and species richness, often on a spatial scale greater than the MPA, thanks to spillover processes (Guidetti & Sala, 2007;Roberts & Polunin, 1991 and references therein), as well as the influence of the fish on the benthic communities through complex trophic interactions (Barrier et al, 2014;Guidetti, 2006;Micheli, Halpern, Botsford & Warner, 2004;Prato et al, 2016;Sala, Boudouresque & Harmelin-Vivien, 1998). Protection and conservation objectives suggest that recreational fishing should be prohibited inside MPAs.…”

Current and potential contributions of the Gulf of Lion Fisheries Restricted Area to fisheries sustainability in the NW Mediterranean Sea

“…Considering that enforcement has demonstrated to be an important feature to achieve ecological benefits in an MPA [78], this calls for a better understanding of the catch data inside the FRA and probably an improvement in the surveillance. Collecting time series of fishing activities inside the CoSEGoL FRA should be a monitoring priority, as previously highlighted for other marine protected areas [31,32,79]. In addition, response functions to sea temperature were included from a global database [64] because we lacked specific response functions in the study area.…”

Comparing commercial, recreational and illegal coastal fishery catches and their economic values: A survey from the southern Mediterranean Sea

“…Data on coastal fishing in the Mediterranean Sea are scarce, rather scattered (Prato et al., ), and few studies considered both commercial and recreational fisheries (see Lloret & Font, ; Albouy, Mouillot, Rocklin, Culioli & Le Loc'h, ; Prato et al., ). Previous studies in the Mediterranean Sea categorised coastal fishing as: commercial and recreational, including spearfishing, rod fishing (boat and shore fishing) and trolling (e.g.…”

“…So, the estimation of the incidence of illegal fishing should be considered as conservative. Illegal fishing could be even more widespread in Tunisia as it is in many coastal zones, among them certain European MPAs (Prato et al., ). Recent evidence on Australia's Great Barrier Reef Marine Park highlighted that illegal fishing is also a serious issue in this iconic MPA, where high levels of poaching have been recorded (Bergseth, Williamson, Russ, Sutton & Cinner, ).…”