Potential use of marinas as nursery grounds by rocky fishes: insights from four Diplodus species in the Mediterranean

Abstract

The construction of marinas along the shoreline has caused substantial habitat destruction within the sheltered coastal areas previously used as nursery grounds by many fish species. However, although the negative ecological impacts of these constructions have been reported extensively, their potential roles in the functioning of the coastal zone remain largely unknown. Here, we surveyed the juveniles of 4 Diplodus species in 5 marinas located along the French Mediterranean coast to assess whether rocky fishes can successfully settle inside these artificialized coastal areas. Inter-specific differences in the spatiotemporal use of the various artificial habitats provided by marinas were investigated between April and August over 2 consecutive years. We also tested the potential benefit of pegging additional artificial habitats (Biohuts) on docks and pontoons to increase their value as fish nursery grounds. Our results suggest that although variations in marina and artificial habitat preferences exist between species, Diplodus juveniles repeatedly colonize marinas. Their average abundances on added Biohut habitats were twice as high as on nearby bare surfaces. This suggests that increasing the complexity of the vertical structures of marinas can considerably enhance their suitability for juvenile rocky fishes, especially at the youngest stages, when mortality is highest. Therefore, as long as marina water quality is well controlled, ecological engineering within these man-made habitats might reduce the ecological consequences of urban development by providing suitable alternative artificial nursery grounds for rocky fishes. Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site.

Innovative solutions for the enhancement of biodiversity on coastal infrastructures : case studies of artificial port nurseries and modular mooring reefs

“…As described in other studies (BOUCHOUCHA et al, 2016;MERCARDER et al, 2017), the micro-habitats complexification of the port infrastructures was associated with positive effects both on species richness and densities of juvenile stages of fish in comparison to non-equipped port infrastructures studied as control sites (LAPINSKI et al, 2015).…”

“…As in other studies (e.g. BOUCHOUCHA et al, 2016), initial monitoring conducted on the inner sides of this port have highlighted that juvenile stages of fish can be observed along pile wharfs and riprap dikes. However, diving observations also concluded that many ecological factors described in suitable Mediterranean nurseries…”

“…It is bio-inspired by the Posidonia oceanica seagrass meadows, one of the most important nursery grounds in the Mediterranean Sea (BOUDOURESQUE et al, 2006). Thus, artificial seagrass is shaped and dimensioned according to the biological characteristics of the plant at low depth (up to 40 cm length for the artificial leafs).…”

“…However, results of ecological monitoring are generally associated with poorer and different mobile and sessile communities in comparison to natural reference ecosystems (AIROLDI et al, 2005;CLYNICK et al, 2007;BURT et al, 2013;BOSCH et al, 2017). If ecological processes which occurred in marine urban zones are still poorly understood, different projects have emerged all around the world in order to improve ecological functions of maritime technical infrastructures (CHAPMAN & UNDERWOOD, 2011;FIRTH et al, 2016;BOUCHOUCHA et al, 2016). Solutions mostly focused on the improvement of construction materials properties (porosity, rugosity, pH), water retention in intertidal areas and habitat complexity (different scale for different stages of life).…”

Marinas as habitats for nearshore fish assemblages: comparative analysis of underwater visual census, baited cameras and fish traps

“…A large number of studies have focused on the role of artificial structures such as fish attracting devices (Carr andHixon 1997, Rilov andBenayahu 2000) and their contribution to increasing fish biomass (Bohnsack 1989). Though marinas are among the most widespread artificial structures along the shoreline of the world, studies focusing on fish assemblages associated with marinas are still scarce (Clynick 2006, 2008, Bouchoucha et al 2016). Breakwaters at the outer sides of marinas are frequently colonized by a range of fishes, at both juvenile and adult stages (Pizzolon et al 2008, Cenci et al 2011, Pastor et al 2013.…”