Table 2. Ranking criteria and logic [24,26] of different resilience and vulnerability attributes used in IRV.
| Attribute | Rank | Criteria | Logic |
|---|---|---|---|
| Resilience attributes | |||
| 1. Growth coefficient (K) | 1 | 0.1–0.6 | Species which exhibit high K values are more resilient. |
| 2 | 0.61–1.2 | ||
| 3 | > 1.2 | ||
| 2. Asymptotic length (L∞) | 1 | > 800 mm | Small size species which exhibit lower L∞ values are more resilient. |
| 2 | 401–800 mm | ||
| 3 | < 400 mm | ||
| 3. Length at maturity (Lm)/L∞ ratio (abs) | 1 | (Lm/L∞ -0.5) = > 0.20 | This ratio indicates the reproductive load of the species. A ratio of 0.5 (median) was ranked highest, and the least deviation from the median was ranked more resilient. |
| 2 | (Lm/L∞ -0.5) = 0.10–0.20 | ||
| 3 | (Lm/L∞-0.5) = < 0.10 | ||
| 4. Number of spawning months (NSM) | 1 | 1 to 4 | A species spawning in all months of the year is more resilient. |
| 2 | 5 to 8 | ||
| 3 | 9 to 12 | ||
| 5. Fecundity (Fc) | 1 | < 25,000 | Species with high fecundity are more resilient. |
| 2 | > 25,000–100,000 | ||
| 3 | > 100,000 | ||
| 6. Coastal productivity index (CPI) | 1 | < 150 | Estimated as a product of monthly Coastal Upwelling Index (CUI) and Chlorophyll-a concentrations from 30 lat-long positions along the Indian coast for the period 1998–2008. This was linked to the species distribution index to arrive at the CPI. Species maximally distributed in highly productive waters are more resilient. |
| 2 | 151–400 | ||
| 3 | > 400 | ||
| 7. Mean trophic level (MTL) | 1 | > 4.0 | Lower trophic level fishes are more resilient. |
| 2 | 3.0–4.0 | ||
| 3 | 2.0–3.0 | ||
| Vulnerability attributes | |||
| 8. Species geographic Distribution (Dist) | 1 | > 65 | Species which have wider geographic distribution are less vulnerable. Species occurrence from catch database across Indian states was used to convert into the area. |
| 2 | 35–65 | ||
| 3 | < 35 | ||
| 9. Body length depth (BLD) ratio | 1 | > 15 | A high ratio indicates species that have a higher probability of escapement through nets, and therefore, are less vulnerable. |
| 2 | 5–15 | ||
| 3 | < 5 | ||
| 10. Exploitation Ratio (Er)—Ratio of fishing mortality to total mortality (F/Z) | 1 | < 0.5 | Species with low Er values are less vulnerable. |
| 2 | 0.5–0.7 | ||
| 3 | > 0.7 | ||
| 11. Length at recruitment (Lr)/L∞ ratio | 1 | > 0.5 | Species which recruit at larger sizes (higher ratio) are less vulnerable. |
| 2 | 0.3–0.5 | ||
| 3 | < 0.3 | ||
| 12. Gear susceptibility (G) | 1 | > 12.5 | The gear ecosystem effects rank of [27] and its product with weighted gear-wise catch is used. High values indicate less vulnerability. |
| 2 | 7.5–12.5 | ||
| 3 | < 7.5 | ||
| 13. Landing Price of species (P) | 1 | High | Species with low market price was given a higher ranking (less vulnerability), considering that it is not targeted by fishers. |
| 2 | Medium | ||
| 3 | Low | ||
All attributes have 3 ranks. Higher rank (#3) indicates high resilience and low vulnerability. Criteria are based on the broad distribution of values (min-max).