ICES Journal of Marine Science: Journal du Conseil

Shyue, Shiahn-wern; Yang, Kuang-che

doi: 10.1006/jmsc.2002.1217pmid: N/A

Although sidescan may be used for approximate delimitation of the boundaries of artificial reefs, multi-beam echosounding technology provides a superior alternative for obtaining quantitative information on sea-bottom morphology and terrain changes around individual reef units. The accuracy of depth measurements of the system used during our trials was around 0.20 m. This allows a grey-scale or colour-code bathymetric map to be drawn from surveying results to demonstrate scouring and sand ripples around reef units. Horizontal movements and subsidence of individual units may be identified from appropriate cross-sections. We found that terrain changes were highly correlated with the direction of local waves and currents. Average width and depth of scouring around concrete reef units and wrecks were approximately equal to the height and to half the height of each unit, respectively. Copyright 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved.

Ponti, Massimo; Abbiati, Marco; Ceccherelli, Victor Ugo

doi: 10.1006/jmsc.2002.1225pmid: N/A

Offshore drilling raises the issue of disposal of platforms at the end of their productive cycle and re-use as artificial reefs has been proposed. The wreck of the “Paguro” drilling platform, which sank in the northern Adriatic Sea in 1965, offers the opportunity to study the performance of offshore structures as artificial reefs in a region where this solution has not been explored before. We provide a description of the macrobenthic assemblages present at the wreck at different sites and at different depths, based on destructive and photographic sampling. Results show that the wreck has been colonized by a rich and diversified fauna. Primary space has been dominated by mussels and oysters, which provide suitable habitats for a variety of benthic invertebrates. Assemblages vary among sites, species richness is greatest at those sites facing prevailing currents. Distribution patterns vary vertically, evenness (Hill's N10) decreasing significantly with depth. It is argued that the results contribute to the background knowledge required in rigs-to-reefs programmes. Copyright 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved.

Jensen, Antony C.

doi: 10.1006/jmsc.2002.1303pmid: N/A

Caselle, J. E.; Love, M. S.; Fusaro, C.; Schroeder, D.

doi: 10.1006/jmsc.2002.1264pmid: N/A

We assessed the significance of offshore oilfield debris as fish habitat in central and southern California using video taken from a remotely operated vehicle to enumerate the fish assemblages and to measure debris characteristics. Among 33 species (belonging to 9 families) identified in four regions (from Pt. Conception to Los Angeles), rockfish (genus Sebastes) made up approximately 78%. Total fish abundance varied by region, with greater numbers present in the west than in the east. In comparing abundance of fish per debris item among regions, two rockfish species showed no spatial differences, one species was significantly more abundant in the western region and one had the highest abundance in the central region. Water depth, vertical profile, shelter availability, and item volume may be used to predict presence/absence or abundance of different species of rockfish, but none of these characteristics was consistently applicable to all species.Copyright 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved.

Collins, K. J.; Jensen, A. C.; Mallinson, J. J.; Roenelle, V.; Smith, I. P.

doi: 10.1006/jmsc.2002.1297pmid: N/A

Scrap tyres have been widely used around the world to construct artificial reefs. They are a popular construction material, being readily available at no cost, durable, and with large void spaces. However, published information about the environmental impact of tyres in the marine environment is limited. When used, successful colonization by epibiota and mobile species seems to be taken as empirical proof of their suitability. In 1998, an experimental scrap tyre artificial reef was constructed in Poole Bay to provide data on the environmental impact of the material. Epibiotic colonization is being monitored for comparison with that on concrete control modules deployed at the same time. Samples of the epibiota have been analysed for heavy metals and organic compounds. Results from the first year of deployment are presented. Copyright 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved.

Baine, Mark

doi: 10.1006/jmsc.2002.1216pmid: N/A

Against a background where a sharp division of stakeholder opinion exists between proponents and opponents, I provide an evaluation of the rigs-to-reefs concept in the North Sea in terms of abandonment legislation, scientific foundation, and perceived acceptability to the environmental and fishing sectors. An analysis of the political situation suggests the need for a revision of the United Kingdom's Best Practicable Environmental Option process. Priority attention should be given to the issues of drill-cuttings piles and the long-term fate of reefs. Offshore reef creation, including deployment in conjunction with a “no fishing” policy, is assessed as politically sensitive and difficult to achieve. Finding supporting beneficiaries and solving cost implications are deemed critical to the planning of a nearshore reef programme. The importance of a genuine stakeholder dialogue process is stressed, as is the crucial role of fishermen to the success of rigs-to-reefs ventures. Copyright 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved.

Sherman, R. L.; Gilliam, D. S.; Spieler, R. E.

doi: 10.1006/jmsc.2001.1163pmid: N/A

The potential for enhancing fish abundance, species richness, and biomass on artificial reefs was examined by attaching floating attractants and manipulating structural complexity of small concrete reefs each approximately 1.3 m in diameter, 1 m high. Experimental design consisted of a comparison of fish assemblages among three treatments (10 replicate, hemisphere-shaped reefs each): 10-m floating line attached (Streamer); concrete block in the central void space (Block); and no floating line or concrete block (Control). Reefs were deployed on sandy substrate at 20-m depth off Fort Lauderdale, Florida, USA. Divers recorded fish census data on slates 18 times over 24 months. Species composition, numbers of individuals per species, and estimated total length (TL; by size class: <5, 5–10, 10–20, and >20 cm) for all fishes within 1 m of each reef were recorded. Size classes were used to calculate fish biomass. There was a significant difference among treatments. Block reefs had higher numbers of individuals, species, and biomass than Streamer or Control reefs (p<0.05). With one exception, Streamer reefs did not differ from Controls for any of the parameters investigated (p>0.05). These results highlight the importance of structural complexity in artificial reefs designed to enhance fish recruitment, aggregation, and diversity. Copyright 2002 Published by Elsevier Science Ltd on behalf of the International Council for the Exploration of the Sea.

Osenberg, Craig W.; St. Mary, Colette M.; Wilson, Jacqueline A.; Lindberg, William J.

doi: 10.1006/jmsc.2002.1222pmid: N/A

Artificial reefs have been proposed as a tool to mitigate impacts on natural reefs, augment natural fish production, and divert detrimental harvesting activities from sensitive natural habitats. The efficacy of this strategy depends on the extent to which artificial reefs contribute to new production or simply redistribute fish during or after settlement. Small coral reef fishes are ideal study subjects because redistribution is most likely during the larval stage, given limited dispersal of benthic stages. We develop a model that incorporates the simultaneous effects of habitat augmentation, competition among reefs for larval settlers, and post-settlement density-dependence, and propose two experimental approaches for evaluating the effects of artificial reefs on local production of natural reefs. One is based on small-scale studies using replicated patch reefs, the other on unreplicated studies using larger reefs and the Before-After-Control-Impact Paired Series (BACIPS) design. Using field data for six fish species, we estimated spatial and temporal variance and thus statistical power of both designs. Power varied among species, but in most cases was sufficiently high to detect local reductions in density of 10–40% with modest levels of replication (6–20 patch reefs or sampling dates). Copyright 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved.

Helvey, Mark

doi: 10.1006/jmsc.2002.1226pmid: N/A

US federal agencies must consult with the National Marine Fisheries Service on actions that may adversely affect “essential fish habitat” (EFH). This EFH mandate coincides with recent discussions on proposed decommissioning of oil and gas platforms in southern California. While many species falling under the Pacific Groundfish Fishery Management Plan (e.g. rockfish, genus Sebastes) inhabit platforms, available information is insufficient for determining whether the structures are necessary to support a sustainable fishery or contribute to a healthy ecosystem, the two basic tenets of EFH. The occurrence of juvenile and large adult rockfish at some platforms suggests that they may support important ecological functions. Because rockfish show long-term population declines, further evaluation of platform ecological structure and function is warranted and should be integrated into the environmental review process. Published by Elsevier Science Ltd on behalf of the International Council for the Exploration of the Sea.

Zalmon, Ilana R.; Novelli, Ronaldo; Gomes, Marcelo P.; Faria, Vicente V.

doi: 10.1006/jmsc.2002.1273pmid: N/A

An experimental evaluation of artificial reefs was carried out on the coast north of Rio de Janeiro, a low-relief bottom area. The reef complex (1500 m2) consisted of two sets (concrete and tire), each comprising 16 modules. Trammel nets were used in monthly samplings of the reef site and a control area. During 2 years of monitoring, 51 fish species were recorded in both areas, of which 24% and 11%, respectively, were found exclusively at the reef and in the control area. The most abundant families were Carcharhinidae, Carangidae, and Triakidae. Based on c.p.u.e. in numbers and weights, density and biomass appear to be higher at the reef site than in the control area. At the reef, species richness and diversity were generally higher during the second year, which may reflect the degree of fouling. Visual observations revealed higher fish diversity on concrete experimental structures than on tire modules. The effectiveness of the reef in creating a complex habitat for the fish community is shown by the dominance of the shark (Rhizoprionodon lalandei), a predator of small teleosts commonly found on the reef structures. Copyright 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved.