Biodiversity Victor Harbor has reported a fish kill event on the Inman River.

In a Facebook post the local environmental conservation organisation says many mature, breeding age, bream are floating along the river bank.

It estimates about 100 fish in about a 100-120m stretch of river in the area opposite the Victor Harbor council chambers. 

The fish mortality has been reported to Landscapes Hills and Fleurieu and to the Primary Industries & Regions South Australia (PIRSA) Fishwatch hotline. 

“An investigation action has been raised with water samples to be taken and a review of the various technical monitoring stations along the river.”

The Inman River is a small river draining the eastern side of the Fleurieu Peninsula.

Biodiversity Victor Harbor has urged the community to quickly report any sightings of mass fish death to the hotline - 1800 064 533, as there is a relatively short timeframe available for a pathology examination to reveal meaningful information.

Responses to the report from other social media users claim that regular fish kill events on the river are caused by agricultural runoff  and landholders drawing too much water from the waterway.

Biodiversity Victor Harbor has asked PIRSA to keep it informed about the investigation and has committed to keeping the community apprised of results.