Climate-induced increases in micronutrient availability for coral reef fisheries

James P.W Robinson,Eva Maire,Nathalie Bodin,Tessa N Hempson,Nicholas A.J Graham,Shaun K Wilson,M Aaron Macneil,Christina C Hicks

doi:10.1016/j.oneear.2021.12.005

Abstract

SummaryClimate change is transforming coral reefs, threatening supply of essential dietary micronutrients from small-scale fisheries to tropical coastal communities. Yet the nutritional value of reef fisheries and climate impacts on micronutrient availability remain unclear, hindering efforts to sustain food and nutrition security. Here, we measure nutrient content in coral reef fishes in Seychelles and show that reef fish are important sources of selenium and zinc and contain levels of calcium, iron, and omega-3 fatty acids comparable with other animal-source foods. Using experimental fishing, we demonstrate that iron and zinc are enriched in fishes caught on regime-shifted macroalgal habitats, whereas selenium and omega-3 varied among species. We find substantial increases in nutrients available to fisheries over two decades following coral bleaching, particularly for iron and zinc after macroalgal regime shifts. Our findings indicate that, if managed sustainably, coral reef fisheries could remain important micronutrient sources along tropical coastlines despite escalating climate impacts.

Highlights

800 million people are undernourished[1] and micronutrient deficiencies are implicated in over three million premature deaths annually,[2] contributing to severe child development problems[2] and estimated reductions in gross domestic product of up to 11%.3 Fish contain micronutrients that are essential to human health, such as iron and zinc,[4] and, through equitable public health policy and sustainable management, fisheries can help to alleviate nutrient deficiencies in malnourished populations.[5]
We find that coral reef fish contain levels of essential dietary nutrients that are comparable with or higher than other animalsource foods, while micronutrient availability for fisheries increased after coral mortality, with iron and zinc levels enriched in fish caught on macroalgal-dominated reefs
Zinc was higher in fish species sampled in macroalgal habitats (+0.36 mg 100 gÀ1) but more variable (50% uncertainty interval [UI] greater than zero), and similar to compositional differences (Figure 2B), whereas intraspecific variation for calcium, selenium, and omega-3 was minimal (Figures 2B and S3)

Summary

SUMMARY

Climate change is transforming coral reefs, threatening supply of essential dietary micronutrients from smallscale fisheries to tropical coastal communities. The nutritional value of reef fisheries and climate impacts on micronutrient availability remain unclear, hindering efforts to sustain food and nutrition security. We measure nutrient content in coral reef fishes in Seychelles and show that reef fish are important sources of selenium and zinc and contain levels of calcium, iron, and omega-3 fatty acids comparable with other animal-source foods. We demonstrate that iron and zinc are enriched in fishes caught on regime-shifted macroalgal habitats, whereas selenium and omega-3 varied among species. We find substantial increases in nutrients available to fisheries over two decades following coral bleaching, for iron and zinc after macroalgal regime shifts. If managed sustainably, coral reef fisheries could remain important micronutrient sources along tropical coastlines despite escalating climate impacts

INTRODUCTION

RESULTS AND DISCUSSION

EXPERIMENTAL PROCEDURES