Survival Rate

The proportion of living fragments at a given point in time — the primary success metric for coral restoration.

$\text{Survival rate} = \frac{\text{fragments alive}}{\text{total fragments}}$

Where:

• $\text{Survival rate}$ = proportion of living fragments (0–1)
• $\text{fragments alive}$ = count of living fragments at the time of observation
• $\text{total fragments}$ = count of fragments at the start of the period

Displayed as a percentage (e.g. 0.85 → 85%).

Aggregation: When combining survival rates across multiple nurseries, pool the raw counts — don't average the percentages, as that ignores differences in sample size.

$\text{Overall survival} = \frac{\sum \text{alive}_i}{\sum n_i}$

Where:

• $\text{alive}_i$ = living fragments in group $i$
• $n_i$ = total fragments in group $i$

See also: Fragment, Nursery