# Global patterns and drivers of fish reproductive potential on coral reefs

## TL;DR

Larger female fish on coral reefs produce disproportionately more eggs, and protecting 30% of reef sites could significantly boost fish reproduction, especially for Serranidae.

## Contribution

The study introduces a novel method to estimate fish reproductive potential at the site-level and evaluates the impact of marine protection on it.

## Key findings

- Reproductive potential scales hyperallometrically with assemblage biomass at the site-level.
- Fully protected sites have higher modelled reproductive potential than fished sites, especially for Serranidae.
- A 30% global protection scenario increases reproductive potential for all fish families.

## Abstract

Fish fecundity scales hyperallometrically with body mass, meaning larger females produce disproportionately more eggs than smaller ones. We explore this relationship beyond the species-level to estimate the “reproductive potential” of 1633 coral reef sites distributed globally. We find that, at the site-level, reproductive potential scales hyperallometrically with assemblage biomass, but with a smaller median exponent than at the species-level. Across all families, modelled reproductive potential is greater in fully protected sites versus fished sites. This difference is most pronounced for the important fisheries family, Serranidae. When comparing a scenario where 30% of sites are randomly fully protected to a current protection scenario, we estimate an increase in the reproductive potential of all families, and particularly for Serranidae. Such results point to the possible ecological benefits of the 30 × 30 global conservation target and showcase management options to promote the sustainability of population replenishment.

This study estimates the reproductive potential of fish in globally distributed coral reef sites. The results show substantial gains in reproductive potential can be achieved through the 30 × 30 conservation target, particularly for the important fisheries family, Serranidae, demonstrating the possible benefit of protection to population replenishment.