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Linking nursery ecological role and trophic pathways with fish population dynamics and diversity (IP -2022-10-7542)

PROGRAMme:

HRZZ Istraživački projekti IP-2022-10

Project name:

Linking nursery ecological role and trophic pathways with fish population dynamics and diversity (IP-2022-10-7542)

Total budget:

173.600,00 €

AKRONYM:

LinkFish

Project duration:

29.12.2023. – 28.12.2027.

Coastal ecosystems, such as estuaries and shallow littoral waters, are often highly productive and provide important habitats for many commercially important fishes and invertebrates that use these areas as nursery, feeding and/or breading grounds. The diversity of coastlines found worldwide results in differences in types of provisioning and function, and in community structure and trophic organisation.

Unfortunately, nowadays marine ecosystems are degraded to the extent that some critical coastal habitats are no longer available or suitable for providing breeding, feeding or spawning functions, which negatively affects the abundance and recovery of populations.

This project is a continuation of HRZZ research project: Coastal nursery habitats: Patterns and processes of demographic variability in marine fish species along the eastern Adriatic coast (NurseFish IP-2016-06-9884; http://jadran.izor.hr/~brankod/NURSE/HR).

The identification of essential habitats for selected species based on otolith geochemistry and the temporal consistency of each site’s contribution revealed that the value and functional role of each individual site varies greatly even over small distances. This raises numerous research questions, primarily related to the observed spatial differences in growth rate and the usage period of specific nursery service by juveniles of specific species.

Within species, it is not clear how behaviour changes in space and time as a function of habitat. We hypothesise that fish behaviour corresponds to adaptive decision-making to avoid poor hydrographic conditions (temperature and oxygen), starvation and predation. Thus, time and space may be important axes on which transient juveniles partition their habitats.

To test this, we need to identify juveniles’ chance of survival and differential growth conditions in different habitats, and determine the success of identified nurseries in fulfilling their functional roles. Spatio-temporal habitat use may indicate nursery functions, including ontogenetic habitat shifts, provision of predator refuge, and appropriate trade-off between food/predation risk, but it is difficult to determine which of the factors is decisive for the observed differences.

Neglecting all or some of the highlighted aspects when identifying and assessing the ecological quality of habitats can lead to suboptimal conservation results, especially given the intense competitive human pressures and severe impacts of climate change affecting all levels of biodiversity.

Ignoring all or some of the emphasized aspects when identifying and assessing nurseries can lead to suboptimal conservation outcomes, especially given the intense competing human pressures and severe impacts of climate change on Mediterranean coasts that affect all levels of biodiversity.

Aims:

The project envisages research with three main goals:

(1) Functional role of estuarine habitats in supporting fishery species to gain an understanding of how fish use different habitats during ontogeny and how a specific nursery shapes juvenile behaviour and growth, and finally how connectivity determines spatial scale between fish populations, population dynamics and stock structure which is ultimately necessary for conservation and management strategies using geochemical analysis of otoliths and stable isotopes analysis of water and otoliths;

(2) Multiple trophic pathways, temporal variations in source contributions and cross-linking between nurseries, since access to rich feeding environments is a key contributor to habitat value, and so knowledge of food webs and feeding relationships, and their spatial and temporal variation, is central to understanding the importance of the different coastal environments while investigation of the trophic pathways and variability in productivity along coastal ecosystems to understand the spatial trophic dynamics are important for fish recruitment;

(3) Assessing anthropogenic pressures on coastal nurseries along the eastern Adriatic coast, given the ever-increasing transformation of coastal landscapes by direct human action or climate change, there is an urgent need to improve our understanding of species’ distribution and ecological preferences to determine marine ecosystem responses to different anthropogenic impacts in the Mediterranean, particularly those that affect juvenile survival in nursery areas.

Project partners

Project leader

Institute for Oceanography and Fisheries,

Leader: dr.sc. Sanja Matić-Skoko

Team members:

dr.sc. Jakov Dulčić
dr.sc. Pero Tutman
dr.sc. Branko Dragičević
dr.sc. Dubravka Bojanić Varezić
dr.sc. Nika Stagličić
dr.sc. Mišo Pavičić
dr.sc. Dario Vrdoljak

Lea Madunić