Contrasting Fish Behavior in Artificial Seascapes with Implications for Resources Conservation

Artificial reefs are used by many fisheries managers as a tool to mitigate the impact of fisheries on coastal fish communities by providing new habitat for many exploited fish species. However, the comparison between the behavior of wild fish inhabiting either natural or artificial habitats has received less attention. Thus the spatio-temporal patterns of fish that establish their home range in one habitat or the other and their consequences of intra-population differentiation on life-history remain largely unexplored. We hypothesize that individuals with a preferred habitat (i.e. natural vs. artificial) can behave differently in terms of habitat use, with important consequences on population dynamics (e.g. life-history, mortality, and reproductive success). Therefore, using biotelemetry, 98 white seabream (Diplodus sargus) inhabiting either artificial or natural habitats were tagged and their behavior was monitored for up to eight months. Most white seabreams were highly resident either on natural or artificial reefs, with a preference for the shallow artificial reef subsets. Connectivity between artificial and natural reefs was limited for resident individuals due to great inter-habitat distances. The temporal behavioral patterns of white seabreams differed between artificial and natural reefs. Artificial-reef resident fish had a predominantly nocturnal diel pattern, whereas natural-reef resident fish showed a diurnal diel pattern. Differences in diel behavioral patterns of white seabream inhabiting artificial and natural reefs could be the expression of realized individual specialization resulting from differences in habitat configuration and resource availability between these two habitats. Artificial reefs have the potential to modify not only seascape connectivity but also the individual behavioral patterns of fishes. Future management plans of coastal areas and fisheries resources, including artificial reef implementation, should therefore consider the potential effect of habitat modification on fish behavior, which could have key implications on fish dynamics. © 2013 Koeck et al.Peer Reviewe

Shallow rocky nursery habitat for fish: Spatial variability of juvenile fishes among this poorly protected essential habitat

International audienc

Information of individual tagged white seabreams concerning their capture, their residency and movement patterns.

<p>(AR: Artificial Reef, NR: Natural Reef, T: Transient fish, NPH: No-Preferred Habitat fish, DP: Detection Period, DR: Detection Rate, RI: Residency Index, SW: SeaWalls, CV: Côte Vermeille, EOPH: Excursions Outside Preferred Habitat for resident fish and outside capture location for the other fish).</p

Correlation plots between control tag detections and raw detections of tagged white seabreams on the artificial reef (AR) and the natural reef (NR).

<p>Correlation plots between control tag detections and raw detections of tagged white seabreams on the artificial reef (AR) and the natural reef (NR).</p

Results of generalized linear mixed models testing the effect of diel phase (day vs. night) and fish size on mean detections per fish movement group and preferred habitat, i.e. detections on NR for NR-residents, on AR for AR-residents and on NR and AR separately for NPH fish.

<p>‘ns’ p>0.05, ‘*’ p<0.5, ‘**’ p<0.01, ‘***’ p<0.001.</p

Results of generalized linear mixed models testing the effect of diel phase (day vs. night) on mean detections of control tags on artificial reef (AR) and natural reef (NR).

<p>‘ns’ p>0.05, ‘*’ p<0.5, ‘**’ p<0.01, ‘***’ p<0.001.</p

Mean detections and standard errors per hourly bin of control tags on the ARs (circles) and on the NRs (triangles).

<p>Detections are standardized by sampling surface and thus expressed per km². Vertical grey lines symbolize mean sunset and sunrise over the entire study period.</p

Study area and acoustic receiver locations.

<p>Grey ellipses around the VR2W receivers correspond to their average detection range (250 m on the NR and 350 on the AR).</p

Chronogram plots of fish #39 an AR-resident (a) and fish #61 a NR-resident (b) over a ten-day period.

<p>Grey areas represent night-time.</p

Wavelet sample spectrums of AR-resident fish #39 (a) and NR-resident fish #61 (b) over the entire detection period.

<p>Continuous lines represent the cone of influence (COI) above which data should not be interpreted. The thick contours represent the 95% confidence level and significant periodicities. Dashed line represents the 24 h periodicity threshold.</p