Posted by Enrique Macpherson
Núria Raventós, Héctor Torrado, Rohan Arthur, Teresa Alcoverro & Enrique Macpherson (2021) Temperature reduces fish dispersal as larvae grow faster to their settlement size. Journal of Animal Ecology DOI: 10.1111/1365-2656.13435
Global climate change has profound implications for benthic fish communities as it mediates critical early-in-life processes during their planktonic phase. We assess how increasing temperatures can influence the potential dispersal and early-life traits of temperate larval fish communities.
We show that increasing temperature (ca. 4ºC) results in considerable reduction (10-25%) in the dispersal potential. Temperature was the strongest driver of larval growth and pelagic larval duration (PLD) – productivity only marginally influencing these trends. This was because, with increasing temperature, larvae grew quicker to their settlement size.
Here is the abstract:
As species struggle to cope with rising ocean temperatures, temperate marine assemblages are facing major reorganisation. Temperature mediates critical early-in-life processes, when many benthic species with a dual life history disperse through the plankton. Impacts of rising temperatures can thus ripple through the population with community-wide consequences. However, responses are highly species-specific, making it difficult to discern assemblage-wide patterns. We show that increasing temperature results in considerable reduction in the dispersal potential of temperate fish. Examining the otolith microstructure of 9 common species across a temperature gradient in the Mediterranean Sea, we find a nearly universal, assemblage-wide decline in pelagic larval duration (PLD) of between 10-25%. This was because, with increasing temperature, larvae grew quicker to their settlement size. Settlement size itself was largely invariant, an apparently ontogenetically fixed, size-dependent process. Declining PLD did not, however, affect post-settlement growth, which was uncoupled from larval growth. These results suggest that evolutionary hard wiring places strong limits to species’ adaptive capacities, resulting in reduced connectivity and population isolation as waters warm.
