Five Maritime Biosecurity Risks That Can Develop During an International Voyage

Five Five Maritime Biosecurity Risks That Can Develop During an International Voyage That Can Develop During an International Voyage

When cargo departs an overseas supplier, many importers assume the biosecurity risk has already been managed. Unfortunately, biosecurity doesn't stop once a vessel leaves port.

International sea voyages can last anywhere from several days to several weeks. During that time, vessels and cargo remain exposed to changing weather conditions, wildlife, insects and environmental contamination. A shipment that was clean at the point of loading can arrive in Australia with entirely new biosecurity risks.

This is particularly relevant for breakbulk cargo, heavy machinery, oversized modules and deck cargo, which remain exposed throughout the voyage.

Understanding these emerging risks allows importers, freight forwarders and project owners to implement proactive controls before a vessel reaches Australia.

1. Birds Nesting and Roosting on Vessels and Cargo
One of the most significant emerging biosecurity risks is the increasing presence of wild birds on international cargo vessels.

Seabirds routinely land on ships during long ocean crossings to rest or seek shelter. Large structures such as cranes, wind turbine components, modules, heavy machinery and industrial equipment provide ideal perching and nesting locations.

Bird activity can result in:

Bird droppings contaminating cargo and vessel structures
Feathers and nesting material accumulating on equipment
Dead birds becoming trapped within machinery or cargo
Potential exposure to diseases such as Highly Pathogenic Avian Influenza (H5 Bird Flu)
While not every bird presents a disease risk, contaminated cargo may require additional biosecurity assessment before it can be released into Australia.

With the emergence of H5 Bird Flu within Australia and neighbouring regions, bird contamination has become an increasingly important consideration for maritime biosecurity.

 
2. Hitchhiker Insects and Spiders
International cargo vessels frequently transport unwanted insects without anyone realising.

During loading, transit and overseas port calls, insects may shelter inside machinery, packaging or cargo itself before travelling thousands of kilometres to Australia.

Common hitchhikers include:

Wasps
Beetles
Moths
Cockroaches
Ants
Spiders
Many species present little concern. Others have the potential to establish invasive populations if introduced into Australia's unique environment.

Insects commonly shelter inside:

Electrical cabinets
Pipework
Machinery voids
Timber packaging
Tarpaulins
Pallets
Structural cavities
Routine inspections throughout the supply chain significantly reduce the likelihood of unwanted pests arriving unnoticed.

 
3. Rodents and Other Vertebrate Stowaways
Cargo vessels naturally attract rodents by providing food, shelter and fresh water during long voyages.

Rats and mice may board ships while alongside overseas ports before moving between cargo, storage areas and machinery throughout the voyage.

Inspectors occasionally encounter:

Rats and mice
Small reptiles
Amphibians
Bats
Other vertebrate stowaways
These animals can contaminate cargo, damage equipment and introduce invasive species or diseases into Australia's environment.

For high-value project cargo and sensitive imports, comprehensive inspections before discharge are essential.

 
4. Organic Contamination During Transit
Cargo doesn't have to leave the supplier contaminated to become a biosecurity concern.

Throughout an international voyage, exposed cargo can accumulate:

Leaves
Seeds
Plant material
Mud
Standing water
Organic debris
Wind, storms, heavy seas and repeated overseas port visits can introduce contamination onto cargo that was previously clean.

Organic material may harbour insects, fungi, weed seeds or other regulated biosecurity risks requiring treatment or further inspection.

This risk is particularly relevant for:

Construction equipment
Mining machinery
Renewable energy components
Modular infrastructure
Heavy industrial equipment
 
5. Marine Growth and Biofouling
Biosecurity risks don't stop at the cargo.

The vessel itself can introduce significant environmental risks through marine biofouling.

Marine organisms including:

Barnacles
Mussels
Sea squirts
Algae
Marine worms
Other aquatic organisms
can accumulate on vessel hulls and submerged structures during international voyages.

If introduced into Australian waters, invasive marine pests can threaten native ecosystems, fisheries and port infrastructure.

Australia maintains strict expectations regarding vessel biofouling management, making proactive hull maintenance and voyage planning an important part of maritime biosecurity.

 
Why Timing Matters
Many export inspections occur immediately before cargo leaves the supplier.

While these inspections remain an essential control, they only provide assurance at one point in time.

Cargo may spend several weeks at sea, during which entirely new biosecurity risks can develop.

For major infrastructure projects involving multiple international shipments, discovering contamination after arrival can result in:

Delays to cargo release
Additional biosecurity inspections
Cleaning or decontamination requirements
Increased project costs
Construction schedule impacts
Vessel delays
Managing these risks before the vessel reaches Australia is often far more efficient than responding after arrival.

 
The Value of Offshore Biosecurity Inspections
Offshore biosecurity inspections provide an opportunity to identify emerging risks before a vessel enters Australian waters.

By inspecting vessels and cargo during transit or prior to arrival, potential issues can often be identified early, allowing corrective actions to be undertaken before biosecurity clearance.

Offshore inspections can identify:

Bird roosting and nesting activity
Bird carcasses
Organic contamination
Hitchhiker pests
Rodent activity
Cargo contamination
General vessel biosecurity concerns
This proactive approach reduces uncertainty, improves compliance and helps minimise costly delays once a vessel reaches Australia.

For complex projects involving breakbulk cargo, heavy machinery, renewable energy components and oversized modules, offshore inspections are becoming an increasingly valuable component of supply chain risk management.

 
Australian Biosecurity Services: Protecting Australia's Border Before Your Cargo Arrives
Australian Biosecurity Services specialises in proactive maritime biosecurity risk management for international supply chains.

Our experienced consultants assist importers, freight forwarders, EPC contractors and project owners through every stage of the import process, including:

Offshore vessel and cargo inspections
Supplier assurance programs
Imported cargo inspections
Biosecurity risk assessments
Biosecurity Management Plans
Regulatory compliance advice
Strategic consulting for major infrastructure, mining, defence and renewable energy projects
We believe effective biosecurity begins long before a vessel enters Australian waters.

By identifying emerging risks early, we help our clients protect project schedules, maintain regulatory compliance and minimise unnecessary delays.

Australian Biosecurity Services Pty Ltd
When Compliance Matters

 
Continue Reading Our Maritime Biosecurity Series
This article is part of our three-part series on managing biosecurity risks in international shipping.

Part 1
Five Maritime Biosecurity Risks That Can Develop During an International Voyage (You're reading it now.)

Discover how biosecurity threats can emerge after cargo leaves the exporting country and why ongoing vigilance is essential during international transit.

Part 2
What Happens During an Offshore Biosecurity Inspection?

Learn how offshore inspections are conducted, what inspectors look for, and how identifying risks before arrival can prevent costly delays at Australian ports.

Part 3
Why Offshore Biosecurity Inspections Save Importers Time and Money

Explore the commercial benefits of proactive biosecurity management, including reduced project delays, smoother import clearance, improved compliance and lower overall supply chain costs.