Ecological Indicators (Feb 2021)
The impacts of climate change on fish growth: A summary of conducted studies and current knowledge
Abstract
Global climate change is increasingly and profoundly threatening fishes, resulting in an uncertain future for both wild fish diversity and global fisheries. Understanding how fish growth responds to changing environments is essential for indicating and predicting the impacts of climate change on fish populations, communities, and even aquatic ecosystems, but the knowledge on this topic remains incomplete, and some findings are contradictory. This study aimed to review the status of current research by analysing data on the environment, species, and response patterns from 1187 documents published from 1976 to 2018, which helped to identify key questions that are currently neglected and potential reasons for these divergences. The results found that 75% of studies were conducted in the field (mostly in temperate and subtropical zones), while the remainder were controlled experiments. Fishes from freshwater ecosystems were relatively less studied than their marine counterparts. Less than 1% of the recorded fish species (309 vs. approximately 35,000) from 30 orders have been studied to examine their growth responses to climate change. All studied fishes were from Actinopterygii. The top three orders were Perciformes, Cypriniformes, and Salmoniformes by species number, while Salmoniformes was the most frequently studied order. The most common habitat type of the studied fish was pelagic, followed by demersal and reef-associated habitats. Small fishes were relatively undervalued in both marine and freshwater systems. The mean trophic levels of the studied species were 3.2 for freshwater fish and 3.4 for marine fish. Carnivores were the dominant trophic guild studied in both marine and freshwater systems. The overall effects of climate change (primarily temperature variables) on fish growth (reflected in physiology and health) were negative at both the global and local scales. Therefore, the results suggested that future studies covering more species (e.g., chondrichthyan fishes, low-level consumers, and small fishes) and areas (e.g., high-latitude areas) are required to obtain a better understanding of climate change impacts on fish growth.
