2022 Field season

Between April and June 2022, we did our first season on the field and gathered hundreds of precious samples to understand the geochemistry of rivers during spring snowmelt and the potential impact of episodic acidification on salmon smolts.

Studied rivers

Between mid April and early June 2022, 5 rivers were sampled for water chemistry (Kedgwick, Northwest Miramichi, Southwest Miramichi, Margaree North, Margaree South), and 3 rivers for salmon (Kedgwick, Northwest Miramichi, Margaree estuary).

The Margaree sampling were done by myself (UNBSJ-INRS ETE). For the Miramichi, it was done by my co-supervisor Dr. Cindy Breau (DFO), and for the Kedgwick by our collaborator Dr. Carole Anne Gillis (GMRC)

First Water sampling

On the 22nd of April 2022, we did the first water sampling of my PhD on the Margaree. We sampled water for 6 different water chemistry parameters (Ions, Dissolved Organic Carbon, Dissolved metals, Organic Aluminum, Total metals and Alcalinity). After lab analysis, we will be able to caracterise the drivers of episodic acidification in rivers from Eastern Canada.

We did water sampling every week between mid April and late June 2022.

First Acidication Events

During the last week of April 2022 , we detected episodic acidification on both Miramichi Northwest and Miramichi Southwest. Water samples were done during such events, and after lab analysis, we will be able to know if aluminum concentrations reached toxic levels for Atlantic salmon smolts as well as the reason why such events happen in those rivers.

Salmon Samplings

During the outmigration of the salmon smolts (May 2022), we captured a total of 90 smolts in 3 different rivers to determine their physiological state before moving to seawater.

Capture

Smolt were captured using rotary screw traps during the night.

Smolt collection and Anesthesia

15 smolts/sampling event were collected. Smolts were euthanised using anesthesia overdose.

Dissection

Fish were dissected for blood, gills, stomachal content, liver, scales and otoliths

Samples

Samples were stored using different methods (liquid nitrogen, alcohol, dry).

pH Stations

pH and water temperature stations were deployed in the Margaree North, Miramichi Northwest and Kedgwick to monitor hourly the pH in those river. That's how we have been able to detect such episodic drops of pH.