Ocean and Coastal Management

Artificial reefs in the Caribbean: A need for comprehensive monitoring and integration into marine management plans

Caribbean coral reefs are in decline and the deployment of artificial reefs, structures on the sea bottom that mimic one or more characteristics of a natural reef, is increasingly often considered to sustain ecosystem services. Independent of their specific purposes, it is essential that artificial reefs do not negatively affect the already stressed surrounding habitat. To evaluate the ecological effects of artificial reefs in the Caribbean, an analysis was performed on 212 artificial reefs that were deployed in the Greater Caribbean between 1960 and 2018, based on cases documented in grey (n = 158) and scientific (n = 54) literature. Depending on the availability of data, reef type and purpose were linked to ecological effects and fisheries management practices around the artificial reefs. The three most common purposes to deploy artificial reefs were to create new dive sites (41%), to perform research (22%) and to support ecosystem restoration (18%), mainly by stimulating diversity. Ship wrecks (44%), reef balls© (13%) and piles of concrete construction blocks (11%) were the most-often deployed artificial reef structures and metal and concrete were the most-used materials. The ecological development on artificial reefs in the Caribbean appeared to be severely understudied. Research and monitoring has mostly been done on small experimental reefs that had been specifically designed for science, whereas the most commonly deployed artificial reef types have hardly been evaluated. Studies that systematically compare the ecological functioning of different artificial reef types are virtually non-existent in the Caribbean and should be a research priority, including the efficacy of new designs and materials. Comparisons with natural reef ecosystems are scarce. Artificial reefs can harbor high fish densities and species richness, but both fish and benthos assemblages often remain distinct from natural ecosystems. Studies from other parts of the world show that artificial reefs can influence the surrounding ecosystem by introducing non-indigenous species and by leaking iron. As artificial reefs attract part of their marine organisms from surrounding habitats, intensive exploitation by fishers, without clear management, can adversely affect the fish stocks in the surrounding area and thus counteract any potential ecosystem benefits. This study shows that over 80% of artificial reefs in the Caribbean remain accessible to fishers and are a risk to the surrounding habitat. To ensure artificial reefs and their fisheries do not negatively affect the surrounding ecosystem, it is imperative to include artificial reefs, their fisheries and the surrounding ecosystem in monitoring programs and management plans and to create no-take zones around artificial reefs that are not monitored. 

Date
2021
Data type
Scientific article
Theme
Research and monitoring
Geographic location
St. Eustatius
Author

How to make Integrated Coastal Erosion Management a reality

Highlights

  • Coastal management is usually too responsive via defense works and not pro-active.
  • Intervention Concerning the Erosion Causes (ICEC) is a suitable future strategy.
  • Restoring sediment production and its flow to and through coastal systems is needed.
  • Restoration of natural protective habitats in the river continuum is recommended.

Coastal-erosion management actions require a knowledge of sediment behaviour and interchange in all related offshore, shore and inland environments. Approaches to managing erosion include hard/soft protection measures (hold/advance the line), accommodation, managed retreat, use of ecosystems and sacrifice (do nothing). In reshaping these options, an essential addition is the most attractive but usually the least used strategy: Intervention Concerning the Erosion Causes (ICEC). Minimizing erosion via ICEC not only means specific local actions, but certainly also involves the restoration of natural protective habitats, and even the removal of anthropogenic structures that block sediment production and its flow to and through coastal systems. The spatial and temporal environmental, physical and social knowledge related to the area of interest forms the core of the ICEC approach to solve or at least minimize coastal erosion.

Date
2018
Data type
Scientific article
Theme
Research and monitoring