Global review identifies opportunities to improve monitoring of juvenile fish habitats

The viability of fish populations is based on healthy habitats where juveniles can appear, feed and develop. Corders of sustainable management of peaches, these habitats are faced with increased pressure from coastal development, climate change, pollution and a number of other factors.

This means that there is an urgent need for better tools to understand which habitats really present for populations of juvenile and adult fish so that they can be preserved and managed. However, there are a number of challenges on how the quality of juvenile habitats are measured.

To try to solve this problem, the members of the International Council for the exploration of the sea working group (ICE) on the value of coastal habitats for exploited species (WGVHES), including

Dr. Benjamin Ciotti from Plymouth University – underlying a complete examination to assess the approaches used to assess the quality of juvenile housing.

They have examined nearly 900 studies from the last five decades covering juvenile fish, crustaceans and molluscs in marine and estuarial systems, with the aim being to assess how the current science assesses the quality of the habitat.

The resulting study, published in Biological journalsemphasizes that despite the generalized recognition of the ecological importance of juvenile habitats, the majority of existing studies employed relatively few measures.

About 85% of research focused on the measure of the abundance of juveniles, generally using methods such as net surveys or visual counts based on divers. Although this provides information on the question of whether a habitat is used by a kind of fish, it necessarily means that they are thriving in these regions.

The working group called for more research taking into account growth and in particular the survival of fish, because while about half of the studies incorporated growth indicators, only 16% included measures of the survival of juveniles. Above all, less than 10% of studies have attempted to directly assess how juvenile habitats contribute to adult populations, which is largely considered to be the best metric of the quality of juvenile habitat.

This close concentration, according to scientists, highlights a major gap in the evidence necessary to assess the quality of the habitat, which in turn leads to a gap between political needs and available sciences, management decisions often based on incomplete or indirect indicators.

“The quality of juvenile habitats for fish populations can be measured in different ways, but none of them is easy. The fact that almost 10% of studies have tried the best and perhaps the most difficult, contribution to the adult population – the stages are taken in the right direction. Ciotti.

This work is at the heart of the WGVHS mission to support protection based on evidence of coastal habitats which underlie the exploited species and describes a clear set of priorities to advance the science of juvenile housing.

It calls for displacements beyond the simple abundance measures to include measures such as survival, growth and contribution rates, because these factors more precisely reflect the quality of the habitat. He also underlines the need to widen the spatial and temporal cover of studies to capture changes in the use of habitat occurring on scales ranging from seasons to tidal cycles.

To better assess the value of the habitat, the authors recommend combining several indicators rather than relying on unique measures, and they highlight the potential of emerging technologies, such as taggage, telemetry and analysis of stable isotopes, to fill the critical data of data.

Finally, the review highlights the importance of following development changes during the life of a fish, recognizing that juvenile organizations often change habitats as they grow.

Overall, the authors of the study say that it lays the foundations for a more robust and biologically anchored approach to identify the essential habitats of fish, and calls for a new generation of surveillance and research to protect the habitats that matter most.

“We live in a time when new technologies such as molecular techniques, cameras and electronic labels are ready to offer enormous information on how juvenile fish use coastal habitats. Says Ciotti.