Substrate and Structure for Farmed Fish

Providing environmental complexity through substrate, refugia, and structure in fish farming systems improves welfare by enabling natural behaviours denied in bare tanks.

Key Facts

Atlantic salmon in the wild occupy structured rocky riverine habitat with complex features
Artificial substrate in tanks reduces aggression and improves distribution of fish
Cover objects reduce stress in flatfish species by allowing partial burial behaviour
Enriched hatchery environments improve post-release survival in restocking programmes

Welfare Considerations

The provision of environmental complexity for farmed fish represents a low-cost, high-impact welfare improvement. Fish in barren tanks cannot perform habitat-seeking behaviours that are intrinsically motivating, leading to chronic frustration. Substrate, cover, and structural complexity also reduce aggression by creating defensible resources and sight barriers. The additional benefit for hatchery fish is improved post-release survival from better environmental preparedness.

What You Can Do

Support aquaculture welfare standards that include enrichment requirements
Advocate for research into cost-effective enrichment provision for commercial aquaculture species
Raise awareness that environmental complexity improves fish welfare across species