Tsawwassen First Nation Investigates Surge in Sturgeon Deaths

The Tsawwassen First Nation is actively investigating a concerning increase in sturgeon deaths along the Fraser River in British Columbia. Earlier this month, a team of four individuals retrieved a carcass of a sturgeon measuring approximately 1.6 meters from the riverbanks in Richmond, B.C. This incident is part of a larger trend, with dozens of sturgeon washing up in recent weeks. The retrieved carcass will be preserved for research purposes, as part of a project aimed at uncovering the reasons behind these mortality events.

Biologist Kelly Scott, working with the Tsawwassen First Nation, emphasized the urgency of the situation. Sturgeons are often referred to as “living fossils,” with a lineage dating back roughly 200 million years. The alarming reports of multiple sturgeon carcasses observed in a single day by local residents highlight a significant environmental concern. Scott noted, “We have gotten multiple reports this year from people who live right on the water in New Westminster saying they’ve seen four, five, six sturgeon at a time, like within one day, floating down the river.”

According to the British Columbia Ministry of Land, Water and Resource Stewardship, there has been a noticeable uptick in sturgeon mortality in 2023. The province reported a total of 71 sturgeon found dead since July, with 65 of those occurrences in the lower Fraser River. Alarmingly, 49 of these reports emerged within the last four weeks alone. In contrast, only 42 sturgeon mortalities were reported in the lower Fraser throughout all of 2022.

Sturgeons are among the largest and longest-living fish species globally, capable of reaching lengths up to six meters and living over 100 years. This fish holds significant cultural and nutritional value for First Nations, including Tsawwassen, which historically harvested sturgeon for food. Since 1994, the harvest of sturgeon has been prohibited in British Columbia, and First Nations have voluntarily ceased their sturgeon fishing activities. Although catch-and-release fishing still occurs for sturgeon in the lower Fraser, the recent spike in deaths has raised questions regarding possible links to increased fishing activities, particularly with the recent recreational opening for sockeye salmon.

Scott pointed out that numerous factors could contribute to the rising mortality rates among sturgeons. Climate change plays a crucial role, as rising river temperatures create stress for the fish. “There’s not a lot of areas with large, shady trees that can provide thermal refuge for the fish,” she explained. Stressed sturgeons are more vulnerable when caught in gill nets intended for other species, further exacerbating mortality risks.

To address the issue, researchers from the Tsawwassen First Nation are tracking the sturgeon. They aim to collect at least 20 carcasses for further study, although many have been too decomposed for analysis. Plans include fitting the carcasses with telemetry trackers to monitor their movements downstream under varying environmental conditions. Scott mentioned, “We want to do it under different conditions, so we would do some upriver, some further down the river, when it’s raining, in the summer, in the winter.”

The research team hopes to collaborate with a researcher from the University of B.C. to utilize environmental genomics, which studies DNA and RNA extracted from the aquatic environment. This approach will help provide insights into the sturgeons’ habitats and stress levels.

The Ministry of Resource Stewardship has acknowledged that multiple factors likely contribute to sturgeon mortality, including disease and elevated water temperatures. A statement from Fisheries and Oceans Canada indicated that recent water temperatures in the Fraser River surpassed 20°C, intensifying the risk of stress and mortality for sturgeon, particularly at temperatures exceeding 18°C.

While the recent increase in fishing activity could correlate with sturgeon deaths, it may also account for the heightened number of reported sightings. Sturgeons are classified as a protected species under federal legislation in much of British Columbia, with certain populations in the region being deemed endangered since 2006.

In response to the ongoing challenges, British Columbia initiated a process in 2021 to develop a comprehensive management plan for white sturgeon across the Fraser River basin. This initiative involves collaboration between provincial authorities and First Nations representatives, ensuring that conservation efforts are guided by a diverse set of stakeholders.

As the investigation continues, the Tsawwassen First Nation remains committed to understanding the factors leading to the deaths of these ancient fish, emphasizing the importance of their survival for both ecological and cultural reasons.