Humankind is increasingly intervening in the coastal zone through the
construction of offshore renewable energy devices and other man-made
sea-floor structures, such as oil rigs and coastal defences. An
artificial reef is a man-made, underwater structure, typically built for
the purpose of enhancing the growth and biodiversity of marine life
around man-made structures or in areas of featureless seabed.
In 2006, SAMS built Europe's largest artificial reef in Loch Linnhe on
Scotland’s West Coast. Findings show that the complex structure of the
SAMS-designed artificial reef can host two to three times the numbers of
conspicuous fish and invertebrates compared with natural reefs or
simple artificial reefs.
Artificial reefs provide hard surfaces to which marine algae and
invertebrates attach. The accumulation of this marine life in turn
provides the intricate infrastructure and food necessary to support
assemblages of fish.
The reef sub-units are designed to be scattered over the material
which is currently used as scour protection at the base of offshore
renewable energy devices. By providing habitat complexity and
encouraging biodiversity, artificial reefs mitigate some of the
environmental impacts of these man-made structures.
Artificial reef building is also effectively used in coral reef
rehabilitation, lobster and fisheries enhancement, creation of oyster
reefs, beach erosion protection and estuary rehabilitation.
The
Loch Linnhe Reef licence was the first consented under new OSPAR
guidelines, necessitating extensive demonstration of the stability of
the reef sub-units. Using purpose built sub-units to make artificial
reefs can overcome many of the problems associated with using "materials
of opportunity," such as stability in storms, durability, biological
fit, lack of potential pollution problems, availability, and reduction
in long term artificial reef costs.
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Low-cost and ease of construction:
The reef is comprised of sub-units made from low-value aggregate,
produced by local quarry. Each reef consists of either 4000 solid or
4000 cavity sub-units, equating to 200–140 tonnes respectively.
Post-deployment construction, combined with low value materials and SAMS
expertise make this cost-effective and environmentally beneficial
solution.
Supporting services and expertise:
SAMS
can provide support in the project-planning phase and the construction
of artificial reefs. SAMS has knowledge and expertise in both Scottish
and international waters. We can also provide survey and consultancy
services relevant to Environmental impact assessment and monitoring for
offshore renewable energy developments. Examples include sea-bed mapping
and oceanographic modelling of currents, as well as sea mammal, fish
and benthic ecology surveys.
Research programmes:
Designed and built by SAMS scientific staff,
the Loch Linnhe Artificial Reef continues to facilitate research into
the interaction between man-made structures and their environment,
including potentially beneficial effects on fisheries and local
biodiversity. SAMS research scientists continue to focus on impacts of
the reef, seasonal variability, habitat complexity, models of water flow
and optimisation of their artificial reef sub-unit design.
