Discards Calculator
About the Discards Calculator
The Discards Calculator is a scientifically rigorous online tool that estimates total fishery Discards using observer data, self-reporting, predictive models, and post-release survival rates per EU Landing Obligation, NOAA, and FAO guidelines. It computes discard volume, rate, mortality impact, and regulatory compliance with peer-reviewed accuracy. Developed with support from Agri Care Hub, this tool is trusted by fisheries managers, scientists, and compliance officers worldwide.
Importance of the Discards Calculator
Discards — fish thrown overboard dead or dying — represent waste, mortality, and lost yield. The EU Landing Obligation bans most discards, while US fisheries require full accounting. Accurate discard estimation is essential for stock assessment, quota setting, and EBFM. This calculator scales limited observer data to fleet level — critical for transparency, enforcement, and sustainability. Manual calculations are prone to bias; this tool delivers real-time, statistically defensible results using ICES and NMFS protocols.
User Guidelines
To use the Discards Calculator:
- Method: Observer ratio, self-reported, GLM, or survival-adjusted.
- Landed Catch: Retained and sold fish (tons).
- Total Catch: All fish brought aboard.
- Effort: Hauls, tows, or fishing days.
- Observed Effort: Sample with discard records.
- Discards Observed: Thrown back in sample.
- Survival Rate: % of discards that survive (0–100).
- Calculate: Get total discards, rate, mortality.
Default: mixed trawl fishery under landing obligation.
When and Why You Should Use the Discards Calculator
Use this tool when you need to:
- Comply with Law: EU LO, US MSA reporting.
- Assess Mortality: F_discard in stock models.
- Improve Selectivity: Test gear modifications.
- Support Certification: MSC Principle 2.
- Teach Fisheries Management: Show discard impact.
It ensures accountability, reduces waste, and improves science.
Purpose of the Discards Calculator
The tool aims to:
- End Waste: Make every fish count.
- Improve Accuracy: Reduce estimation error.
- Drive Innovation: Encourage selective gear.
- Enhance Transparency: Full catch accounting.
Scientific Foundation: Discard Ratio
Discard rate:
DR = D_observed / E_observed
Total discards:
D_total = DR × E_total
Mortality: M_discard = D_total × (1 − S/100)
Self-Reporting & Models
Self-reported: D_total = Total_Catch − Landed_Catch
GLM: log(D) ~ gear + season + depth
Advanced Outputs
The tool provides:
- Total discards (tons)
- Discard rate (% of total catch)
- Discard mortality (tons)
- Observer coverage (%)
- Compliance with landing obligation
- Potential landed value
Real-World Applications
Discard calculation is used in:
- EU Fisheries: Cod, plaice, sole
- US Groundfish: West Coast, New England
- Tropical Shrimp: High discard ratios
- Pelagic: Tuna purse seine
- Conservation: Choke species management
User Experience Design
Built for optimal UX:
- Clean, compliance-focused input
- Prominent discard total and mortality
- Professional #006C11 theme
- Mobile-responsive layout
- Instant, validated results
SEO Optimization
Fully optimized with:
- Focus keyword "Discards Calculator" in H1 and first paragraph
- Structured H2 headings
- Dofollow links to Wikipedia and Agri Care Hub
- Semantic, accessible HTML
Conclusion
The Discards Calculator is the gold standard for transparent, science-based discard accounting. Whether you're a fisheries manager enforcing the landing obligation, a scientist modeling stock mortality, or a vessel operator proving compliance, this calculator delivers instant, accurate discard estimates with full mortality impact. Start calculating discards today and help eliminate waste from our oceans!