Mesh Size Calculator
About the Mesh Size Calculator
The Mesh Size Calculator is a scientifically robust online tool that determines optimal codend Mesh Size using L50, MLS, maturity, and yield-per-recruit models from ICES, FAO, and peer-reviewed gear selectivity studies. It predicts retention, escape probability, and regulatory compliance with full transparency. Developed with support from Agri Care Hub, this tool is trusted by gear manufacturers, fisheries managers, and scientists worldwide.
Importance of the Mesh Size Calculator
Mesh size is the primary gear control measure in trawl and gillnet fisheries, directly influencing selectivity, discards, and stock sustainability. Too small mesh causes growth overfishing; too large reduces catch efficiency. This calculator uses established L50-to-mesh relationships (Wileman et al., 1996; Herrmann et al., 2009) to recommend science-based mesh sizes — essential for EU Common Fisheries Policy, US Magnuson-Stevens Act, and MSC certification. Manual calculation is complex; this tool delivers instant, defensible results.
User Guidelines
To use the Mesh Size Calculator:
- Mode: L50, MLS, maturity, or YPR-based.
- L50: Desired length at 50% retention.
- SR: Selection range (L75 − L25).
- Species: Preloaded L50-mesh relationships.
- Twine & Hanging: Affect effective opening.
- Calculate: Get mesh size, curve, compliance.
Default: 100 mm codend for North Sea cod.
When and Why You Should Use the Mesh Size Calculator
Use this tool when you need to:
- Comply with Regulations: EU mesh rules, US gear zones.
- Reduce Discards: Increase L25 above MLS.
- Protect Juveniles: Align L50 with maturity.
- Optimize Yield: Maximize YPR via selectivity.
- Design Gear: Test mesh-twine combinations.
It ensures sustainability, legality, and efficiency.
Purpose of the Mesh Size Calculator
The tool aims to:
- Improve Selectivity: Let small fish escape.
- Reduce Mortality: Lower discard impact.
- Support Policy: Evidence-based mesh rules.
- Enable Innovation: Test new materials.
Scientific Foundation: Mesh-to-L50
Empirical relationship:
L50 = a × Mesh + b × Twine + c × Hanging
Species-specific coefficients from selectivity trials.
Selectivity Curve
Logistic model: S(L) = 1 / (1 + exp[(L50 − L)/(SR/(2×ln(3)))])
Advanced Outputs
The tool provides:
- Recommended mesh size (mm)
- Predicted L50, L25, L75
- Interactive selectivity curve
- Compliance with MLS/maturity
- Escape probability by length
Real-World Applications
Mesh size regulation is used in:
- EU Demersal Fisheries: Cod, haddock, plaice
- US Groundfish: West Coast, Alaska
- Shrimp Trawls: Tropical, cold-water
- Gillnets: Salmon, herring
- Conservation: Turtle Excluder Devices
User Experience Design
Built for optimal UX:
- Interactive Chart.js visualization
- Real-time mesh and curve updates
- Professional #006C11 theme
- Mobile-responsive layout
- Instant, validated results
SEO Optimization
Fully optimized with:
- Focus keyword "Mesh Size Calculator" in H1 and first paragraph
- Structured H2 headings
- Dofollow links to Wikipedia and Agri Care Hub
- Semantic, accessible HTML
Conclusion
The Mesh Size Calculator is the gold standard for science-based gear design. Whether you're a fleet operator upgrading codends, a regulator drafting mesh rules, or a scientist modeling selectivity, this calculator delivers instant, peer-reviewed mesh recommendations with full selectivity curves. Start calculating mesh size today and help build a more selective, sustainable fishery!