Protected Species and Marine Aquaculture Interactions

Table 10 Overview of potential effects on seabirds from shellfish farming
(adapted from Clement et al. 2013)
Effects
Entanglement (resulting in
birds drowning)
Management Options
Careful site selection to avoid critical
breeding and foraging habitats
Habitat exclusion
Providing roost sites closer to
foraging areas
Aggregation of prey fish
Ensure waste material and debris are
collected and disposed of correctly
Minimize lighting at night
Monitoring and reporting of negative interactions
of seabirds with aquaculture structures
Sharks
We found no published reports on sharks being entangled in aquaculture gear, and
there is little published information about the interactions of sharks and marine farms.
Sharks have been documented as being attracted to fish cages in the Pacific Northwest
(Nash et al. 2005), Puerto Rico (Alston et al. 2005), The Bahamas (Benetti et al.
2005), Latin America (Rojas & Wadsworth 2007) and Australia (Department of Sustainability,
Environment, Water, Population and Communities 2013). Because sharks
pose a threat to the stocked fish and potentially divers, dangerous
species may be destroyed. In Australia, an estimated
20 great white sharks Carcharodon carcharias a year are killed
at marine aquaculture farms (Department of Sustainability,
Environment, Water, Population and Communities 2013).
Siting of a salmon farm off South Africa within an ecologically
significant great white shark congregation area and
eco-tourist destination elicited major negative public response
(Scholl & Pade 2005), and the farm was later closed.
A telemetry study of sandbar Carcharhinus plumbeus and
tiger Galeocerdo cuvier sharks near fish cages off Hawaii
found that sharks did aggregate near the cages with some individuals
being recorded for the entire term of the 2.5-year
study (Papastimatiou et al. 2010). These animals were considered
to pose minimal threat to humans.
The economic and ecological potential risk of large scale fish releases due to
sharks tearing nets may be a concern as the industry moves into offshore sites (Holmer
2010) depending on the types of nets and locations used. Technological improvements
in shark resistant aquaculture cage materials decreases the predation risk that
sharks pose to aquaculture and may deter them from damaging farm equipment.
Great white shark
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