JCU research highlights critical fish habitats
Researchers have discovered that estuaries and salt marshes are many times more valuable as fish nurseries than was previously thought.
Estuaries and salt marshes are often heavily impacted by human development and this new research highlights the importance of their protection and repair to protect fish stocks.
Marine biologists from Australia’s James Cook University, Adelaide and Griffith universities have identified 10 key components provided by coastal, estuarine and salt marsh ecosystems that contribute to nursery ground value.
“Estuaries and other coastal ecosystems have long been known to support offshore fish populations by providing the new juveniles needed to support population numbers,” explains Professor Marcus Sheaves from JCU’s Centre for Tropical Water and Aquatic Ecosystem Research (TropWATER).
“But now we realise that this nursery value depends on complex and interacting biological processes.”
Not only does nursery value depend on a range of biological processes but the contribution to offshore ecosystems goes far beyond the supply of new juveniles.
“Juveniles moving offshore are little packets of nutrients that are transferred to offshore ecosystems, so even if they are eaten before they enter adult populations they contribute to offshore food webs,” says Dr Ron Baker of TropWATER.
The success of life in juvenile nurseries also impacts on the functioning of offshore ecosystems. For example, predatory fish that grow up in estuarine nurseries are vital in controlling offshore fish populations.
Understanding this complexity offers the chance to gain a more realistic picture of the value of coastal habitats and the opportunity for more comprehensive and effective management.
The realisation of much greater complexity of coastal nursery functioning could be seen as making them much harder to understand, evaluate and manage, but this need not be the case.
“Scientists around the world are already doing much of the research needed to understand this complexity and include it in management—we just need to learn how to bring it together effectively,” points out Professor Sheaves.
The research “True Value of Estuarine and Coastal Nurseries for Fish: Incorporating Complexity and Dynamics,” has recently been published in the “Perspectives in Estuarine and Coastal Science” section of the international science journal, Estuaries and Coasts, and is authored by Marcus Sheaves, Ron Baker, Ivan Nagelkerken and Rod Connolly.
Marine Biology at James Cook University
JCU, through its School of Marine and Tropical Biology, is the first university in Australia to offer specialized training in marine biology. It has earned an international reputation for excellence in both teaching and research and takes a field-oriented, hands-on approach to its teaching and research endeavours.
The school’s location in the tropics allows students and research staff ready access to a wide variety of tropical marine systems including coral reefs, tropical estuaries, mangrove habitats and seagrass beds. Links between JCU’s research and teaching programs ensure that students are at the cutting edge of marine research.