Table 1.
Benchmarking of outlined BC approaches according to the criteria of (i) Sensitivity (S), where 3 is expected to provide a strong reflection of animal's true energy stores while 1 is expected to provide only an approximate and indirect indication. (ii) Nonlethal (NL), measure is awarded a score of 1 if it can be applied nonlethally. (iii) Cost‐efficiency (CE), on a scale of 1–3, where 3 indicates a measure that is both inexpensive to derive and easy to measure. By contrast, 1 indicates a measure that is both cumbersome and expensive to obtain. (iv) Versatility (V), is ranked on a scale of 1–5, related to suitability for application in dead as well as living animals, large as well as small species of cetaceans, immatures as well as adults and finally, suitability for pregnant females. An “*” denotes that a measure that has the potential to be applied for this category, but that species‐ and category‐specific validation and optimization remains to be performed
| Approach | Measurement | Measurement variant | Idea measurement criteria | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| S | NL | CE | Versatility | Final score | ||||||||
| Life status | Suitable for large cetaceans | Suitable for immatures | Suitable for pregnant females | V score (out of 5) | ||||||||
| Dead | Alive | |||||||||||
| Blubber measures | Blubber mass | 3 | 0 | 1 | 1 | 0 | 0.5 | 1 | 1 | 3.5 | 7.5 | |
| Blubber thickness | Direct measure | 1 | 1 | 1 (2 if live) | 1 | 1 | 1 | 0 | 1 | 4 | 8 (7) | |
| Ultrasound | 1 | 1 | 1 | 1 | 1 | 1 | 0.5 | 0 | 3.5 | 6.5 | ||
| Blubber lipid content (%) | 0.5 | 1 | 3 | 1 | 1 | 1 | 0 | 1 | 4 | 8.5 | ||
| BTLM | 3 | 0 | 1 | 1 | 0 | 0.5 | 1 | 1 | 3.5 | 7.5 | ||
| Adipocyte metrics | Adipocyte area | 2 | 1 | 2 | 1 | 1 | 1 | 0 | 1 | 4 | 9 | |
| Adipocyte index | 2 | 1 | 3 | 1 | 1 | 1 | 0 | 1 | 4 | 10 | ||
| Body composition | Carcass analysis | Bomb calorimetry | 3 | 0 | 1 | 1 | 0 | 0.5 | 1 | 1 | 3.5 | 7.5 |
| Fat mass estimation | 3 | 0 | 1 | 1 | 0 | 0.5 | 1 | 1 | 3.5 | 7.5 | ||
| Isotope dilution | 2 | 1 | 1 | 0 | 1 | 0 | 1 | 1 | 3 | 7 | ||
| Glide pattern analysis | 3 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 4 | 9 | ||
| Body morphometry | Measurements | Body girth | 2 | 1 | 2 | 1* | 1 | 1 | 0.5* | 0.5* | 4 | 9 |
| Body girth‐length | 2 | 1 | 2 | 1* | 1 | 1 | 0.5* | 0.5* | 4 | 9 | ||
| UAV‐photogrammetry | 3 | 1 | 2 | 1* | 1 | 1 | 0.5* | 0.5* | 4 | 10 | ||
| Chemical biomarkers | POPCI | 2 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 4 | 8 | |
| Omics | ? | 1 | ? | 1 | 1 | 1 | 1* | 1 | 5 | ? | ||