A long-term industrial nutrient pollution source exist to the west of the cuttlefish breeding reef at the Whyalla steelworks. There, ammonia is a byproduct of its coking process for steelmaking, and is discharged into Spencer Gulf via reed-beds and settling ponds. North of the cuttlefish aggregation, sea cage farming of yellowtail kingfish occurred commercially from the late 1990s until 2011. Fish farming is another nutrient pollution source, as uneaten feed and fish waste enter the water column and sediment. Northern Spencer Gulf in an oligotrophic inverse estuary with naturally low levels of nutrients cycling through it. A potential exists for anthropogenic nutrient pollution to cause eutrophication in the region with associated ecological impacts to the cuttlefish and wider ecology.