Abstract Artificial reefs (ARs) have been deployed on the inner shelf of Paraná, Southeast Brazil, as protection against destructive trawling activities, and to offer habitat for local fauna for recovery of biodiversity. The purpose of this study was to develop a preliminary characterization of the ichthyoplankton community associated with both artificial and natural reefs in the Currais Archipelago, and perform a comparison of fish larvae composition between ARs and nearby unconsolidated substrate. Two sampling methods were used, light traps and a plankton net. A total of 12 families and 14 species were identified, expanding the total species list in the area by eight species and three families. Differences among assemblages on ARs and unconsolidated substrate indicate that ARs seem to be effective attractors to fish larvae. Particular attention is drawn in regard to the "attractor effect" for exotic species that do not naturally reside in the area, such as Omobranchus punctatus. The large abundance of fish eggs on ARs suggests that these artificial structures can improve local production. These results are the first step needed to better define guidelines for sustainable use and management of ARs and Currais Archipelago, a Marine National Park.

The factors that influence the selection of marine macrophytes by meso-herbivores are complex, and may include the nutritional quality of algae, the value of the habitat as a shelter, and the availability of algae in the environment. Here we investigated the existence of differential use of Sargassum filipendula C. Agardh, 1824 (Phaeophyta) and Galaxaura stupocaulon Kjellman, 1900 (Rhodophyta) as habitats and feeding resources by species of Hyalidae and Ampithoidae, in laboratory manipulation experiments and in an algal bed on the northern coast of the state of São Paulo, Brazil. In the field, 19 fronds were collected from each alga and the associated amphipods were identified and counted. To evaluate food preference and habitat selection by amphipods, we conducted laboratory experiments using containers containing fragments of algae and individuals of Cymadusa filosa Savigny, 1816 or Hyale nigra (Haswell, 1879). In natural conditions, the density of C. filosa was significantly higher on G. stupocaulon, while in the feeding and habitat preference experiment we found a higher density on S. filipendula. The densities of H. nigra did not differ between the algae in both experiments, probably as a result of the variety of food items in its diet, and its high mobility and wide distribution on different substrates. The different results for C. filosa suggest that the pattern of feeding and habitat selection can be affected by external characteristics of the algae; probably, refuge from predation is an important selective force acting on the use of algae by these animals.

Coastal regions are subject to various forms of environmental impacts, such as spills of crude oil and associated products, with a wide range of effects on benthic biodiversity. This study characterized the patterns of recolonization of the macrofauna associated with the brown alga Sargassum cymosum(C. Agardh), on fronds contaminated by diesel oil in a small-scale field experiment. We collected 40 fronds of S. cymosum from an algal bed in southeastern Brazil and defaunated each frond by immersion in fresh water. Half of the fronds were then immersed in seawater (control group) and the other half in a mixture of 50% diesel oil and 50% seawater (impacted group). The test fronds were returned to the algal bed, and natural recolonization took place over a period of 12 days. Samples of the vagile macrofauna were taken randomly at three-day intervals over the course of the recolonization period. No significant differences in the densities of most taxa were found between the impact treatment (IG) and control treatment (CG). At the end of the recolonization period (day 12), the faunal composition of the treated fronds was very similar to the natural conditions, indicating a high rate of community recovery and suggesting that benthic associations can be rather resilient to diesel-oil impacts on a small scale.