Global fish production may be threatened by anthropogenic disturbances, such as climate and land use change, that can decrease fish caught in lake fisheries. Reduced catches threaten food security and livelihoods of millions of people worldwide, especially in impoverished countries where rural or poor communities lack alternative sources of animal protein and employment opportunities. Fisheries are particularly vulnerable to changes in their surrounding environment because fish are cold-blooded and their distribution is usually limited by temperature or habitat structure and chemical composition. Environmental changes driven by climate and land-use change, like shifts in regional temperature or precipitation, have already been linked to major shifts in global lake catches. Therefore, understanding this threat is crucial to effective inland fisheries management, but global knowledge on lake fisheries is still limited despite the importance of these ecosystems.

A new study recently published in Nature Communications and funded by the National CASC addresses this need to understand how climate and land-use change affect lake fish catches on a global scale. Here, scientists identified the effects of climate and land-use change on fish catches from 1970 to 2014 in 31 lakes spanning Africa, the Americas, Asia, and Europe and in both tropic and temperate regions. Specifically, researchers used carefully selected modeling techniques called Bayesian networks modeling (BNM) to analyze the data for each lake sampled over time, an approach which allowed researchers to assess how different drivers of climate and land-use change shifted when fish catches decreased by 25%. This study also included a secondary analysis to determine whether socio-economic characteristics associated with fish catches or physical classification characteristics of the sampled lakes were correlated with any of these perceived shifts.

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The results show that global fisheries catches can be impacted positively or negatively by climate and land-use change. For example, fish catch was reduced in lakes exposed to both colder and warmer air temperatures, both higher and lower precipitation rates, and both increasing and decreasing land use. Additional findings illustrate that a lake located in a region with greater access to clean water is less likely to experience a substantial decrease in fish catch, even in the face of climate and land-use change. This suggests that fish catch for lakes in sub-Saharan Africa, Southeastern and Central Asia, and Central and South America are more vulnerable to climate and land-use change, which may have dangerous implications for the local communities who subsist on the fish produced by lake fisheries in these regions. These secondary results suggest that investing in water-quality protection and efficiency can provide benefits to lake fisheries and food security. Overall, findings from this research will be used to predict how inland fisheries production may by altered under different future scenarios of climate and land use change.

For more information on this research, check out this article written by lead author Yu-Chun Kao of Michigan State University and published in the Nature Research Community’s Ecology and Evolution (NatureEcoEvo).

This study is a product of a larger National CASC funded project, Evaluating Future Effects of Climate and Land Use on Fisheries Production in Inland Lakes.