Crews continue to clean up the fuel spill from last week's fiery crash between a tanker and pickup truck. (CBC)

Government officials are looking into a report that dead fish were found near the site of last week's fuel spill on West Barneys River, in northern Nova Scotia.

Angler Steven Clapperton said he discovered 30 dead salmon or trout fingerlings about one kilometre downstream from the spill site on Saturday.

"What I saw alarmed me because the oil was in the system now," said Clapperton, host of a fishing show on EastLink cable TV. "It was getting on the grass, in the mud."

A tanker truck owned by Newalta Corp., an industrial waste management firm, collided with a pickup truck on Highway 104 last Wednesday, killing both drivers. Some of the 38,000 litres of used oil in the tanker spilled into the river nearby.

Crews used excavators, containment booms and absorbent pads to try to clean up the fuel from the river and its banks.

Angler Steven Clapperton says the samples of fish he collected are being tested. (CBC)

Clapperton, who travels the river three or four times a week, blames what he saw on the fuel spill.

But that surprises officials, who have been patrolling the riverbank for days.

"We were really surprised and that's when the investigation and the assessment started going full bore, because we obviously didn't see anything," said Kim Bard, onsite inspector for Nova Scotia's Department of Environment.

"Everyone I've spoken to, they say they haven't seen any dead fish. They've seen a lot of live, active fish," said Bill Locke, with the trucking company that's paying for the cleanup.

Clapperton said samples of what he found are being turned over for toxicology testing and analysis.

Environment Canada said no dead fish were observed during three site visits since the accident.

The Department of Environment said the cleanup in the Barneys River area is between 85 and 90 per cent complete. About 2,000 tonnes of contaminated soil has been removed, along with 181,000 litres of contaminated river water.

The department says the federal Department of Fisheries and Oceans is heading up the investigation into the apparent fish kill. No one from DFO responded to CBC's request for more information.

Environment Canada said samples of the spilled waste are being analyzed in an Alberta lab to determine the chemical make-up of the oil and to test for the presence of contaminants such as PCBs and heavy metals.

Spokesperson Henry Lau said results are expected to be available around Sep. 1.