August

Spatial response of plaice and sole to climate changeby Arnaud Dupond and Alix Pascal

Published by Charlotte Recapet the August 3, 2020 on 7:54 AM

Scientists admit that climate change is one of the main driving forces which change species distribution and abundance in many ecosystems.

In this case, a modification of abiotic variables can affect the “niche concept” and can also change species geographical distributions. For the marine environment, this notion of geographical dependence is important. Indeed, marine organisms show several distinct stages during their life and each of these stages evolve in a specific habitat.

The objective of this study was to use different models based on physiological aspects and environmental variables in order to estimate habitat occupation by plaice and sole under different climate change scenarios in the North Sea.

How to reach this objective?

To predict new habitats, researchers considered environmental variables and determined their effect on the food web, but also the effect of the food web on the water chemistry.  To do that, the ecosystem model used functional groups of taxa. Their taxa are phytoplanktonic, planktonic and macrobenthic organisms. Some of them have a direct effect on the water chemistry and are regulated by other taxa. The food web is also used to quantify the availability of the habitat’s resources. Thanks, of this two types of model results fit more precisely reality of the distribution.

The sample strategy is built like this, data are collected daily on surface of 10x10km sin the North Sea.

Figure 1: Schematic simplification of the models used in the studies

Results of the study

The model of environmental variables shows the predictions for temperature and food conditions between 1989 and 2002. This data showed benthic production is concentrated along the southern coast during the year 1989, whereas in 2002 is concentrated in the Southern bight (figure 2).

Figure 2: Comparison of the benthic production between 1989 and 2002 in the North Sea

An important fact is that the temperature rate inside of which the growth is positive will change with the size of the fish and according to abundance of food (the more food is abundant the higher rate of temperature is). Indeed, bigger fish need higher temperature to grow optimally. Figure 3 defines the areas of maximum potential daily growth of each class size of plaices in 1989 at the left, and in 2002 at the right.

Figure 3: Comparison between the three size ranges of plaices and soles, of the speed growth in regard of two environmental parameters, the food availability and the temperature

The results for maximum potential growth per day seem to give the same result as the estimate of average abundance. (Figure 4).

Figure 4: Comparison of the plaice and sole abundance distribution in the North Sea

Conclusion

For the plaice, migrations during different stages of life maximize their physiological performance during the summer season, in the winter, the adult’s distribution is determined by the best spawning habitat and shows maximisation of their fitness. Sole differs in their physiological traits and have a higher optimal growth temperature which explains the difference in life habitat. As for plaice, the area indicated high quality habitat for the different size class.

This study can predict the evolution of species distribution with a model of environmental changes and one of physiological changes but in our case,  we can just explain data collected not the prediction made with the model.

Read the full study: Teal, L.R., van Hal, R., van Kooten, T., Ruardij, P. and Rijnsdorp, A.D. (2012), Bio‐energetics underpins the spatial response of North Sea plaice (Pleuronectes platessa L.) and sole (Solea solea L.) to climate change. Glob Change Biol, 18, 3291-3305. https://doi.org/10.1111/j.1365-2486.2012.02795.x

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