Assessment of commercial and recreational fishing effects on trophic interactions in the Cap Roux area (north‐western Mediterranean)

Abstract

ABSTRACT1. Assessing both direct and indirect effects of fishing, i.e. effects extending to two or more trophic levels, is becoming a key issue in restoration ecology. The present study compared the Cap Roux no-take area (NW Mediterranean) with the surrounding non-protected areas.2. Direct effects of fishing were investigated using experimental net fishing and underwater visual census (UVC) specifically to survey species targeted by commercial fishing and angling. Indirect effects of fishing were deduced from predation and density of sea urchins.3. Observations showed higher biomass and abundance (from catch rates) inside the MPA and differences in size composition (from UVC). The effect of protection from fishing was rapid, with differences apparent within 5 years of protection, and was most evident for highly targeted fish.4. Rates of predation on two species of sea urchin (Paracentrotus lividus and Arbacia lixula) were dependent on protection level and season. This pattern was consistent with the presence of large Diplodus spp., known sea urchin predators, observed inside the reserve only in winter. However, the density of the sea urchins did not differ between the MPA and adjacent fished areas.

A long-term survey of Posidonia oceanica fish assemblages in a Mediterranean Marine Protected Area: emphasis on stability and no-take area effectiveness

“…Even if the density of the serranid S. scriba, a piscivorous fish targeted by angling, was higher in the no-take zone, the expected positive evolution of the refuge effect was not visible. S. scriba is known to be highly vulnerable to angling as well as Serranus cabrilla, which preferentially lives in rocky reefs (Harmelin et al 1995;Lloret et al 2008;Seytre et al 2013). The present results could be explained by the weak angling pressure exerted in the Scandola area and specially on the seagrass beds where the sampling was realised or by an already established reserve effect.…”

“…Through trophic cascades, fishing prohibition can influence other trophic levels, such as invertebrates or algal communities(Babcock et al 1999;Duffy et al 2005;Valentine and Heck 2005;Ritchie et al 2012;Seytre et al 2013 but see…”

Comparative analysis of artisanal and recreational fisheries for Dentex dentex in a Marine Protected Area

“…These restrictions tend to decrease fishing pressure on the protected parts and increase catches in terms of CPUE in these areas (Mouillot et al 2008). The increase in the abundance of exploited species can be rapid, but the recovery of age-and size-structures might only occur after a longer period of protection (Seytre et al 2013). A likely hypothesis is that a long period (several decades) of fishing prohibition is necessary to reach a complete reserve effect that could lead to an increase in catches for fishers outside the protected zone, as part of a density-dependent process (Seytre & Francour 2008).…”

“…In the Mediterranean, fish are heavily exploited by commercial fishing but recreational fishing is also intensive along the Mediterranean coast (Seytre et al . ). Recreational fishing in the Mediterranean can be defined as follows: all non‐commercial fishing carried out mainly for pleasure or sport, where the catch – the sale of which is illegal – is used for private consumption (Font et al .…”

“…Artisanal fishing is a complex system characterised by commercial fishers operating in small boats, exploiting areas near the coast, using a large number of gears and techniques, typically manned by a single fishers or a pair of fishers and targeting a high diversity of species (Colloca et al 2004;Gomez et al 2006;Lloret & Font 2013). In the Mediterranean, fish are heavily exploited by commercial fishing but recreational fishing is also intensive along the Mediterranean coast (Seytre et al 2013). Recreational fishing in the Mediterranean can be defined as follows: all non-commercial fishing carried out mainly for pleasure or sport, where the catchthe sale of which is illegalis used for private consumption (Font et al 2012).…”