Biodegradable marine nets are often presented as the future of sustainable fishing.
The idea is attractive: if a net is accidentally lost at sea, it should gradually lose strength and break down instead of remaining active for years as ghost gear.
However, this does not mean every fishing operation should immediately replace conventional nylon, polyethylene, or polypropylene netting.
A biodegradable net must perform two very different jobs:
It must remain strong enough during normal fishing.
It must lose functional strength within a useful period if it is lost.
That balance is difficult to achieve.
If the material weakens too quickly, it may fail during the fishing season. If it remains strong for too long, it may provide little reduction in ghost fishing. Field studies have shown that biodegradable gillnets can work under commercial conditions, but catch efficiency, mechanical performance, cost, and fisher acceptance can differ from conventional gear.
The right question is therefore not:
“Are biodegradable nets better?”
It is:
“Which fishing operations gain the most environmental benefit without creating unacceptable operational risk?”
Passive fishing gear is left in the water and catches animals without being actively towed by a vessel.
Examples include:
Gillnets
Trammel nets
Pots and traps
Fyke nets
Some stationary coastal nets
These operations are among the strongest candidates for biodegradable components because lost passive gear may continue catching animals long after the fisher has lost control of it.
FAO notes that lost gillnets may continue ghost fishing for months or even years, depending on local conditions. Biodegradable materials or mechanisms that disable unattended gear may help reduce this continuing mortality.
By contrast, an actively towed net usually stops fishing once towing ends, although it may still create entanglement and plastic-pollution risks after loss.
This makes unattended passive gear a more urgent starting point.
Seasonal small-scale gillnet fisheries may be among the most realistic early adopters.
These fisheries often have:
Clearly defined fishing seasons
Relatively short soak times
Regular retrieval
Moderate operating depths
Familiar fishing grounds
Smaller vessels
Repeated use of standardized panels
A biodegradable gillnet can be designed to remain functional through the expected season while gradually becoming less capable of fishing if lost.
A 2024 Mediterranean field study tested bioplastic gillnets on 10 small inshore vessels over 12 months, demonstrating that this technology can be evaluated under real fishing conditions rather than only in laboratories.
However, adoption should follow controlled trials because changes in stiffness, visibility, knot behavior, and breaking strength may affect catch performance.
Biodegradable gillnets may be worth testing where:
Net-loss rates are relatively high
Ghost fishing is a recognized local problem
The season is short and predictable
Fishing occurs in sheltered or moderately exposed waters
Gear can be inspected frequently
Target species do not require extremely high-impact netting
Caution is needed where:
Nets remain deployed for very long periods
Strong currents create heavy cyclic loading
Large fish regularly strike the net
Rocky seabeds create severe abrasion
Winter conditions are extremely cold
Gear must remain reliable for several seasons
Trammel nets contain multiple netting layers and can remain effective after loss because animals become entangled between the panels.
That makes them relevant candidates for biodegradable materials.
Some studies have reported similar fishing efficiency between biodegradable and conventional trammel nets under particular test conditions, while other research has identified lower efficiency or mechanical differences. The results indicate that performance depends strongly on material design, species, and fishing method. (ScienceDirect)
A full switch should therefore not be based on environmental claims alone.
Operators should compare:
Catch per unit effort
Species composition
Damage rate
Handling characteristics
Knot stability
Strength retention
Seasonal replacement frequency
Where conventional trammel nets are frequently lost and continue ghost fishing, even partial replacement with tested biodegradable panels may create meaningful benefits.
Trap fisheries may not need to replace the entire structure.
A more practical solution is often to use a biodegradable component that disables the trap after prolonged loss.
Examples include:
Biodegradable entrance ties
Degradable escape-panel fasteners
Weak links
Timed-release cords
Biodegradable door-securing twine
During normal use, the component keeps the trap operational.
If the trap is lost, the fastener eventually weakens, opening an escape route and reducing ghost fishing.
This approach has several advantages:
The main trap remains durable
Less biodegradable material is required
The failure point can be designed deliberately
Replacement costs may be lower
Performance is easier to test
Environmental benefits are concentrated where they matter most
For many trap fisheries, switching one critical fastening component may be more realistic than manufacturing the entire trap from degradable material.
The environmental value of biodegradable gear increases when the probability of accidental loss is high.
Common causes of gear loss include:
Severe weather
Strong currents
Vessel traffic
Propeller contact
Conflicts between fishing methods
Poor seabed holding
Damaged marker buoys
Deep-water deployment
Lost position records
Theft or accidental cutting
A fishery that rarely loses gear may gain less from biodegradable netting than one where lost panels and traps are a recurring problem.
Before switching, operators or fisheries managers should examine:
How much gear is lost each year
Which gear types are most often lost
Where loss occurs
Whether gear is normally recovered
How long lost gear remains active
Which animals are affected
Biodegradable products should be prioritized where the lost gear causes the greatest ongoing ecological damage.
Small-scale coastal fisheries can be good candidates because their operations are often shorter, closer to shore, and easier to monitor.
Potential advantages include:
Easier recovery of test gear
Frequent visual inspection
Shorter fishing seasons
Lower individual gear size
Faster feedback from fishers
Easier comparison between biodegradable and standard panels
European projects have already explored biodegradable materials for artisanal fishing gear as part of efforts to reduce ghost gear and marine plastic pollution. (Oceans and fisheries)
However, small-scale fishers often operate with narrow margins. Even an environmentally beneficial product may not be adopted if it:
Catches fewer fish
Costs significantly more
Requires frequent replacement
Is difficult to repair
Handles poorly on small boats
Recent research suggests that fisher willingness to adopt biodegradable gear is strongly connected to whether its catch efficiency is comparable with conventional gear. (ScienceDirect)
Research operations are another suitable area for early adoption.
Examples include:
Seasonal stock surveys
Fish-tagging projects
Short-term species monitoring
Temporary sampling nets
Coastal ecological experiments
Juvenile-fish surveys
Selectivity trials
Research gear is normally retrieved, but loss can still occur because of storms, vessel traffic, anchor failure, or seabed obstruction.
Biodegradable gear may be especially appropriate when:
The sampling period is clearly defined
Gear is used for weeks or months rather than years
Mechanical loads are moderate
Researchers inspect it frequently
Catch efficiency can be carefully measured
Accidental loss would otherwise create ghost-fishing risk
Scientific programs can also collect the detailed performance data needed before larger commercial adoption.
Not all marine nets are used to catch market fish.
Temporary nets may also be used for:
Seasonal fish-guidance systems
Coastal restoration work
Temporary exclusion zones
Juvenile protection
Research enclosures
Short-term jellyfish barriers
Environmental monitoring
Small habitat trials
Biodegradable netting may reduce long-term plastic persistence if part of the structure is accidentally lost.
However, it must not be treated as disposable.
Project operators still need:
A recovery plan
Regular inspections
Secure anchoring
Wildlife-risk assessment
Clear deployment dates
Emergency-removal procedures
Suitable disposal after retrieval
Biodegradability is a backup risk-reduction feature, not permission to abandon equipment.
Biodegradable gear may deserve priority near habitats where lost conventional gear causes particularly serious damage.
Examples include:
Coral reefs
Seagrass beds
Mangrove channels
Marine protected areas
Nursery grounds
Shellfish beds
Areas with turtles or marine mammals
Important seabird-feeding zones
Lost gear in these locations can entangle wildlife, abrade habitat, and remain difficult to recover.
However, biodegradable gear can still cause damage before it loses strength. It may continue trapping animals for a meaningful period after loss.
Therefore, sensitive-habitat operations should combine biodegradable materials with:
Gear marking
Accurate position recording
Low-loss anchoring systems
Rapid reporting
Recovery teams
Escape mechanisms
Limits on unattended soak time
Biodegradable gear may become more attractive where buyers, regulators, certification schemes, or fisheries-management bodies require stronger action on plastic pollution and ghost fishing.
Possible drivers include:
Eco-label requirements
Marine-protected-area rules
Government pilot programs
Retail sustainability standards
Procurement policies
Producer-responsibility systems
Lost-gear reporting requirements
However, environmental labels should be examined carefully.
Biobased, biodegradable, and compostable do not mean the same thing. European policy guidance distinguishes these terms and emphasizes that degradation claims must be linked to defined environmental conditions. (Environment)
A product that composts in an industrial facility may not biodegrade effectively in cold seawater.
Some fishing operations currently face greater risk from early material failure than from the environmental benefit of biodegradation.
Bottom trawls experience severe towing force, seabed abrasion, catch loading, and impact.
Research is being conducted on biodegradable trawl twines, but this remains a demanding application in which long-term strength and abrasion resistance are critical. (ScienceDirect)
A premature full-net switch could increase:
Net tears
Lost catch
Emergency repairs
Further gear loss
Fuel consumption
Operational downtime
Specific biodegradable components or experimental panels may be more appropriate than immediate full conversion.
Main cage nets must protect high-value stock continuously for long production cycles.
Premature weakening could cause:
Fish escapes
Predator entry
Structural failure
Major financial loss
Ecological interaction with farmed stock
Biodegradable material may be more suitable for temporary internal partitions or noncritical components than for the main containment wall.
Permanent marine barriers face continuous cyclic loading, biofouling, storms, and abrasion.
Until strength retention is demonstrated over the full design life, conventional high-durability materials may remain safer.
Low temperature may slow biodegradation while also changing material stiffness and impact behavior.
A net that degrades successfully in warm coastal water may remain persistent in cold deep water or may not maintain adequate operating strength.
If a net must remain reliable for several years without frequent inspection, early strength loss may create unacceptable risk.
The decision does not need to be all or nothing.
Fishing operations can begin with:
Biodegradable trap ties
Escape-panel fasteners
Selected gillnet panels
Short seasonal fleets
Low-risk fishing areas
Scientific trial gear
Temporary internal partitions
Sacrificial components
This allows operators to measure real performance without placing the entire operation at risk.
A staged trial can compare:
Catch efficiency
Breaking strength
Knot performance
Handling
Repairability
Fouling
Strength after immersion
Loss rate
Cost per trip
Fisher acceptance
Full conversion should follow evidence, not marketing pressure.
There is no universal answer.
The required strength-retention period depends on the operation.
A seasonal gillnet may need to remain reliable for several months.
A trap fastener may need to remain secure for normal soak periods but weaken after prolonged abandonment.
A temporary research barrier may require only several weeks of service.
A suitable product must therefore have a planned performance window:
The gear must retain a reliable safety margin during normal use.
After extended accidental loss, it should weaken enough to reduce entanglement or continued capture.
The transition between these phases must be predictable.
Research reviews have cautioned that some biodegradable fishing products reduce ghost-fishing risk partly because they begin with lower strength or durability—not necessarily because they undergo a perfectly controlled gradual decline after loss. (ScienceDirect)
That distinction is important. A weaker net is not automatically a better environmental product if it fails during normal fishing and becomes additional lost gear.
A fishing net is not adopted only because it is environmentally preferable.
It must still catch the intended species effectively and selectively.
Biodegradable materials may differ from conventional nylon or polyethylene in:
Stiffness
Elasticity
Visibility
Diameter
Density
Knot size
Mesh opening under load
Movement in currents
These differences can affect how fish approach, contact, or escape from the gear.
Some field studies have produced promising results, while others have identified reduced fishing efficiency. (FAOHome)
Every fishery should therefore conduct its own controlled comparison before a large purchase.
The word “biodegradable” is not enough.
Buyers should ask:
Was the material tested in seawater?
At what temperature?
At what depth?
For how long?
Was the test performed on film, raw resin, twine, or finished net?
Did the material truly biodegrade or only fragment?
How much strength remained over time?
Were degradation products assessed?
Does fouling change the result?
A finished twisted or monofilament net can behave very differently from a thin laboratory sample.
Marine biodegradation evidence should be relevant to the actual product and fishing area.
Initial breaking strength describes only the new product.
For biodegradable gear, buyers also need:
Knot strength
Elongation
Abrasion resistance
Cold- and warm-water behavior
Strength after one month
Strength after one season
Performance after sunlight exposure
Batch consistency
Storage requirements
Repair compatibility
Expected post-loss weakening period
The key measurement is not simply how strong the net is today.
It is whether its strength remains within the correct range throughout the planned fishing period.
Biodegradable netting may cost more at purchase.
Its real value should be evaluated through:
Total operating cost = gear price + replacement + repair + catch impact + handling + lost-gear risk + environmental compliance
A more expensive biodegradable net may make sense where:
Gear loss is frequent
Recovery is difficult
Ghost fishing is costly
Regulations are tightening
Sustainable sourcing improves market access
Environmental damage carries legal or reputational risk
It may make less sense where early replacement sharply increases material use, labor, and operational disruption.
An operation is a stronger candidate for biodegradable marine nets when most of the following are true:
The gear is passive
Lost gear continues fishing
The season is short and predictable
Gear-loss risk is meaningful
Operating loads are moderate
Inspection is frequent
Catch performance has been tested
Product degradation is proven in local conditions
Failure would not create a major safety or containment event
Recovery remains standard practice
An operation should proceed cautiously when:
Loads are severe
Abrasion is high
Gear is used for several years
Conditions are very cold
Inspection is difficult
Failure could release valuable stock
No field data are available
The supplier cannot explain strength retention
The fishing operations most ready to switch to biodegradable marine nets are not necessarily the largest or most technologically advanced.
They are the operations where lost gear continues causing damage, service periods are clearly defined, loads are manageable, and performance can be monitored.
Seasonal inshore gillnets, trammel-net fisheries, trap escape components, small-scale coastal operations, temporary research gear, and selected projects in sensitive habitats are among the strongest candidates.
High-load trawling, permanent offshore containment, extreme cold-water operations, and multi-year structures require much greater caution.
The most practical path is usually gradual adoption:
Test one component. Compare it with conventional gear. Measure catch, strength, wear, and handling. Then expand only when the evidence supports it.
Biodegradable fishing gear is not a substitute for retrieval, tracking, repair, and responsible disposal.
Its greatest value is as a final layer of protection—reducing the long-term consequences when prevention and recovery fail.
