When we restore rivers, we often focus on habitat. But what if the biggest limitation for threatened freshwater predators is actually food? New Fish Futures research, led by by Drs Simon Steward and Robin Holmes, has found that restoring migrations of small fish, which provide an important food source for longfin eels (tuna), can dramatically increase eel growth and productivity.
Key findings were:
- Longfin eels grow around 350% faster when migratory prey fish were available.
- Restoring food web connections can boost eel production, even in heavily modified agricultural catchments.
- Small migratory fish bring valuable energy from the ocean into freshwater ecosystems, supporting native predators.
- Conservation efforts that reconnect rivers, wetlands and the sea may deliver benefits that go far beyond habitat restoration alone.
- The study highlights the exciting potential of foodscape restoration: rebuilding the food web connections that help freshwater ecosystems thrive.
The team has also written an article in The Conversation – have a read here.