Background
Marine biofouling refers to the unwanted aquatic organisms that attach to the submerged areas of man-made structures in the ocean. This is an issue of particular concern for ship hulls that travel great distances and therefore carry species to new environments where they may become invasive.
The impacts of non-indigenous species (NIS) transfer via biofouling pose a major threat to the health of the world’s oceans. It is crucial to plan preventative and control measures according to scientific evidence to make the efforts as effective as possible. WG 44 was created to gather and assess relevant scientific knowledge to help inform these mitigation efforts.
Workshop(s) and report
WG 44 held meetings/workshops in [location(s)] on [dates]. The workshop aimed to identify and describe the various pathways (e.g., shipping, fishing, off-shore operations) for NIS transfer and its various impacts e.g., on environments, biodiversity, human health and socioeconomic factors. They also reviewed best management practices for biofouling and identified remaining knowledge gaps.
The results of this work were collated in GESAMP Reports and Studies 114, “Marine biofouling: Non-indigenous species and management across sectors”.
Please find WG 44’s Terms of Reference on page 17 of this report.
Main findings
All commercial and recreational sectors deal with biofouling and its usually undesirable consequences. Sectors examined in the report are vessels (shipping, fishing, recreational), aquaculture, marine offshore energy, offshore renewable energy, ocean-observing infrastructure (i.e., monitoring and research instruments) and marine debris.
The report reviewed various consequences of biofouling, not necessarily associated with NIS transfer. They found that biofouling can:
· transfer non-indigenous species to new environments where they may become invasive,
· increase weight and drag, thus reducing the speed of the vessel,
· compromise structural integrity of wood, steel, concrete and netting,
· reduce efficiency of vessel cooling systems (e.g., by reducing heat exchange or blocking water flow),
· obstruct meshes in aquaculture to reduce water flow and waste removal, compete with commercial species for light and nutrients and/or directly harm the livestock,
· block and/or contaminate filter membranes in industrial desalination plants,
· have various ecological consequences including altering habitats, changing the food web composition, competing for light, space and nutrients, introducing new diseases,
· have direct and indirect economic consequences such as maintaining/repairing/replacing instruments and higher uncertainties surrounding decision-making,
· and be dangerous for human health and safety. For example, by creating slippery surfaces or exposing people to infective diseases.
All marine resource managers (local and global) are concerned with the threat of invasive species.
To date, most strategies and tools that prevent, reduce or manage biofouling primarily focus on protecting the performance and structural integrity of the surfaces that biofouling communities attach to. Preventing biofouling as a vector for the transport of invasive species is usually a secondary consideration.
WG 44 concluded that all current strategies, tools, or regulatory measures have both strengths and limitations which vary depending on context. Additionally, the level of risk of NIS transfer also differs between contexts.
Overall, WG 44 found that there is no single ‘best solution’ for each sector. Combinations of policies, measures, and regulations must be adapted to best suit the specific context.
Recommendations for future work
To increase the effectiveness of prevention/reduction of invasive species transmission (improving existing policies, measures, and regulations, adopting new ones):
· Regulatory frameworks should have clear standards and be appropriate for the sector.
· Adequate monitoring and capacity to ensure compliance are necessary.
· Frameworks should be regularly updated as additional knowledge and innovations become available.
· Frameworks must not cause other unintended environmental consequences.