Collaborative science and conservation of wide-ranging species
We know that fish don’t respect state and territory borders, yet often recovery and research efforts for native fish happen within jurisdictions. Whilst the work being done is important and valuable, imagine what can be achieved through collaboration.
This month World Fish Migration Day 2024 is happening on the 25th of May! It is a day to celebrate existing and renewed free-flowing rivers, and act as stewards for migratory fishes.
During the Native Fish Forum 2024, Brenton Zampatti from CSIRO explored this very phenomenon in his presentation through recent Australian case studies.
The story of the Pouched Lamprey
The Pouched Lamprey (Geotria australis) spends most of its adult life at sea. However, the species migrates into rivers to spawn.
The spawning run can involve distances of hundreds of kilometres; however, the movement of the species is still rather cryptic within the Murray-Darling Basin. Much of the knowledge we have about their migratory patterns comes from Western Australia and New Zealand. The Pouched lamprey has the widest distribution of all lampreys, with a broad southern temperate distribution including Australia, New Zealand and Chile. Globally, its conservation status is unclear. However, it is known to have declined in Australia and New Zealand. It is listed as Endangered in the Action Plan for South Australian Fishes and is considered ‘vulnerable’ under the Adelaide and Mount Lofty Ranges national recovery plan.
In Fishes of the Murray-Darling Basin, Mark Lintermans notes that the biggest threat to this unique species is the barriers to fish movement which restrict spawning migration.
In his presentation, Brenton spoke about the Sea to Hume Fish Passage Program. The program saw 14 weirs and tidal barrages adapted with fishways to accommodate movement. This program has been instrumental in reconnecting fish passage to 2200 km of river.
Additionally, Brenton spoke about the ongoing research happening to understand Pouched Lamprey movement. PIT tag technology was used to track the movement of the species across state lines. The results of the PIT tag research found that they moved 604 km in 23 days. This is about 26 km per day! This amazing insight into Lamprey migration was made possible through the collaboration of CSIRO and SARDI researchers, overcoming jurisdictional boundaries for the pursuit of collective knowledge.
For more on this awesome project, check out the video below:
The story of the Golden Perch
Golden Perch (Macquaria ambigua) are an iconic species throughout the Basin and both adult and immature Golden Perch are migratory. Movements of more than 1, 000 km have been recorded in adult movement upstream, however these movements are uncommon and are usually associated with large floods. Movement downstream has also been recorded in spawning events.
Brenton spoke to some new research being undertaken with Golden Perch to further understand their movements. The process of collecting and analysing otoliths has been identified as a crucial part of understanding population demographics and habits of Golden Perch.
Otoliths are the ear stones of fish, and can be used to determine a fish’s history, including its age, where it was born, what sort of habitat it has lived in and potentially even its diet. This critical information enables scientists and fish and water managers to understand what conditions can best facilitate population growth.
The developments in otolith research have allowed scientists to track the movement of Golden Perch throughout an individual fish’s lifetime. The tiny otolith grows in rings, similar to rings of a tree, that can be used to collect data like age. The otolith, however, holds a chemical signature in its rings that record the different water chemistries that Golden Perch dwell in as they move and age. These chemical signatures are known as variations of strontium isotope ratios (87Sr/86Sr). Each river system has a unique ratio that is reflected in the otolith. By measuring variation in river water 87Sr/86Sr throughout the Basin, researchers have been able to create a strontium isoscape for the Murray-Darling Basin. This is then matched with otolith 87Sr/86Sr to connect Golden Perch to specific locations at specific life stages.
From this information, researchers have been able to conduct modelling of Golden Perch populations, migration patterns, and determine the influence of flows on Golden Perch movement. Additionally, the research team were able to create a whole of River Murray perspective, bringing together a larger picture of Golden Perch across the different reaches.
The collaboration beyond the science
Both of these stories tell the tale of two very unique migratory fish species in the Murray-Darling Basin. However, without the joint effort of people across the far-reaching locations these fish travel to, this science would not have been possible. Brenton urged the audience to consider the importance of education, partnerships and relationships in the freshwater space.
Additionally, Brenton addressed the importance of including multiple perspectives in research and management actions. He introduced the concept of Two-Eyed Seeing which embraces “learning to see from one eye with the strengths of Indigenous knowledges and ways of knowing, and from the other eye with the strengths of mainstream knowledges and ways of knowing, and to use both these eyes together, for the benefit of all,” as envisaged by Elder Dr. Albert Marshall. This concept is increasingly important as we look to the future of native fish conservation. Brenton reminds us that native fish recovery and conservation is as much about the people as it is about the fish!
Future considerations for wide-ranging fish species
- Flow and connectivity at scales relevant to the population process of fish.
- Flow integrity along entire river systems, all the way to the Murray Mouth.
- Consideration of non-flow impacts e.g. habitats, water quality, invasive species.
- Education, partnerships and relationships.
For more engaging content from the Native Fish Forum 2024, click here.
Featured image: Pouched Lamprey
Source: Michael Hammer
