Three estuarine fish species show genetic resilience to extreme heat

Yellowfin bream, sand whiting and tarwhine possess a genetic ability to withstand extreme temperature conditions, according to a peer-reviewed study led by Adelaide University researchers and published in Global Change Biology. The study focused on three economically important estuarine fish species that inhabit habitats with widely variable temperatures and characterized all three as “thermal generalists.” The supplied research summary does not report numerical survival measurements, experimental temperatures or statistical estimates of thermal tolerance, so it does not establish how far these populations can persist under prolonged ocean warming.

Project leader Professor Ivan Nagelkerken, of Adelaide University’s School of Biological Sciences, said climatic extremes are increasing in frequency, intensity and duration across Earth’s biomes as a consequence of anthropogenic climate change. In aquatic systems, climatic extremes can rapidly restructure communities, disrupt ecosystem functioning and compromise ecosystem services, including fisheries productivity. The study examined the resilience of yellowfin bream, sand whiting and tarwhine and attributed their ability to tolerate extreme conditions to genetic traits. The findings indicate that inherited differences in thermal tolerance may influence how estuarine species respond to future warming.

Dr Angus Mitchell performed the study, which focused on the three species because of their important role in the fisheries industry. Yellowfin bream and sand whiting are among the most commonly caught inshore species by recreational and commercial fishers on Australia’s east coast. Because these are species taken home by fishers, the research examined their capacity to cope with warming estuaries, a question with direct relevance to fisheries supporting coastal communities. The source does not provide catch totals, economic values, catch projections or a direct forecast of future fish abundance.

The results do not indicate that all marine species can withstand continued warming. Many marine habitats are already experiencing changes in species distribution as waters warm, with tropical species moving farther south and changing which fish support local fisheries. Nagelkerken said estuarine species with broad thermal tolerance may hold their ground, but that this resilience will not extend to species with narrower limits, such as coral reef fishes. The evidence therefore supports a distinction between the tested estuarine “thermal generalists” and species with narrower temperature limits, rather than showing that warming has no ecological consequences for marine fish.

Genetic thermal resilience also does not remove other threats facing estuaries. The research release notes that estuaries are increasingly subject to human pressures such as pollution and overfishing. It presents the findings as a qualified sign of potential resilience, not a guarantee of secure fisheries, and emphasizes the need to manage estuaries well to sustain species that may be comparatively resilient to future climate conditions. No specific management measures or environmental thresholds were evaluated, and the study does not establish the relative importance of warming, pollution, overfishing or other pressures for the long-term persistence of these three species.

Subject of Research: Genetic thermal resilience in three economically important estuarine fish species

Article Title: Some fish might thrive in a warming climate

Article References: Some fish might thrive in a warming climate. Original publication (Bibliographic details unavailable.)

Image Credits: AI Generated

DOI: Not provided

Keywords: climate change, ocean warming, estuarine fish, thermal tolerance, yellowfin bream, sand whiting, tarwhine, fisheries resilience, species redistribution, estuarine management, Some, fish