You cannot ‘offset’ extinction

A lack of quantitative evidence indicates that habitat offsetting is unlikely to compensate for the negative effects to salmon caused by a bigger port in the Fraser Estuary.

A version of this article was published by the Seattle Times on February 16, 2022 and the Vancouver Province on February 19th, 2022.

Globally, only 15.5% of the world’s coastal regions remain ecologically intact. In British Columbia, the Fraser River Estuary has already lost 85% of its floodplain habitat and over 100 species that live there are at risk of extinction. Now, they face another threat. 

​​The Vancouver Fraser Port Authority (the Port) wants to double the size of its shipping terminal at Roberts Bank in the Fraser Estuary.  A growing body of evidence indicates that habitat offsetting cannot counteract the serious effects the massive Terminal 2 (T2) expansion will have on the habitat of threatened and endangered species.  

As a nursery and feeding ground, the Fraser Estuary connects a food web linking fish, birds and marine mammals across thousands of kilometres of the North Pacific Ocean. Even at a fraction of their former abundance, the estuary is the rearing grounds for Canada’s largest runs of Pacific salmon. It is critical habitat for endangered Southern Resident killer whales who follow adult Chinook salmon to their natal river, and more than 100 other species at risk of extinction call the estuary home. 

The federal government’s environmental assessment of Roberts Bank Terminal 2 (T2) was clear. In a 613 page report, the Impact Assessment Agency of Canada (the Agency) identified that T2 would incur adverse cumulative effects on juvenile Chinook salmon from the Lower Fraser and South Thompson rivers. These Chinook populations are the primary fish that Southern Resident killer whales forage on in the summer months. The Agency concluded that the loss of these Chinook salmon for Southern Resident killer whales would be regional in extent, permanent in duration, irreversible, and continuous. Read that again, continuous and irreversible. 

A container ship get loaded at a terminal near Vancouver.
Photo by Michael O. Snyder.
Vancouver Fraser Port Authority.
Photo by Michael O. Snyder.

For the already nutritionally-stressed Southern Residents, this does not bode well. Coupled with a loss of prey, the whales would also be subjected to an increase in underwater noise. The expansion of the terminal will result in a further increase in shipping traffic in the Salish Sea. Southern Residents are already in the presence of boats and ships 85% of the time they use the inside waters of the Salish Sea, and reductions in feeding success in the presence of vessels can be as high as 19%. As such, the Agency concluded that the increase in marine shipping associated with the project would result in a significant adverse cumulative effect on Southern Resident killer whales. Between an increase in underwater noise and declining Fraser Chinook abundances that are anticipated from Terminal 2, it is probable that these conditions would increase their likelihood of extinction to above 26% by the end of this century.

In the same report that outlines the significant and irreversible impacts Terminal 2 will have on Chinook salmon and Southern Residents, it also discusses “offsetting” these negative effects. But can you compensate for permanent impacts on species that are already at risk of extinction? 

Habitat offsetting emerged as a strategy to reduce the negative effects to biodiversity that result from development. However, due to a lack of evidence demonstrating the effectiveness of offsetting, there have been significant concerns regarding its use to make up for destroyed habitat. The problem with habitat offsetting is that you can’t “replace” nature. 

In the Fraser River Estuary, a 2016 study found that among offsetting sites implemented between 1983 to 2010, only 33% of sites attained their intended biological function and goals. The study found that even after three decades, time did not make a positive difference in meeting these objectives. 

The Lower Fraser Region is not alone in failing to offset negative impacts from development. A Canada-wide study of fish habitat compensation projects found that 50% were not compensating for damages on a 1:1 ratio. The researchers determined that it was simply not possible to compensate for some habitats.

Failure to provide adequate information on offsetting plan

In the Agency’s report, it was clearly stated that the Port’s proposed plan to offset a total of 29 hectares is not sufficient to compensate for the loss of habitat and productivity that will occur from the 177 hectares of terminal development. For Chinook salmon, it was stated it is unlikely that there are sufficient offsetting opportunities for Chinook in the project vicinity to compensate for the lost productivity. Even the Port’s most recent response with an updated offsetting plan (December 2021) cannot alleviate the concerns.

In December 2021, the Port provided an updated habitat offsetting plan to the newly elected Minister of Environment and Climate Change, Steven Guilbeault. The updated information proposes mitigation projects that make a suite of assumptions, assign subjective values to habitat quality, and use models to predict whether these projects will work. 

However, there is no evidence indicating that these mitigation projects will be effective in compensating for the negative effects to Chinook salmon and Southern Resident killer whales. As such, it is unlikely that the Port’s offsetting plan will compensate for the adverse effects incurred on Chinook salmon from the project, as habitats are not like-for-like in their functionality to juvenile salmon. Speculation from the proponent’s modeling does not meet the standard of evidence-based mitigation.

On February 9th, a group of renowned scientists with expertise on Chinook salmon, Southern Resident killer whales and the Fraser Estuary co-authored a letter to Minister Guilbeault which outlined the biological rationale for rejecting T2. They stated that the proposed mitigation measures by the Port are insufficient to offset the damages that will incur to habitat, and if Canada is committed to recovering at-risk species the project must be rejected. 

The bottom line is that you cannot offset extinction. If the development of Terminal 2 pushes Southern Resident killer whales and populations of Fraser River wild salmon into extinction, can it ever be worth it? 


Kristen Walters is the Lower Fraser Salmon Conservation Program Coordinator for Raincoast Conservation Foundation. 
Misty MacDuffee is the Wild Salmon Program Director at Raincoast Conservation Foundation. 
Chris Genovalli is the Executive Director of Raincoast Conservation Foundation.


Bull, J.W., Suttle, K.B., Gordon, A., Singh, N.J. & Milner-Gulland, E.J. (2013). Biodiversity offsets in theory and practice. Oryx, 47(3), 369-380.

Fisheries and Oceans Canada. (2019). Cumulative Effects Assessment for Northern and Southern Resident killer whale (Orcinus orca) Populations in the Northeast Pacific

Gardner, T.A., Von Hase, A., Brownlie, S., Ekstrom, J.M., Pilgrim, J.D., Savy, C.E., …& Ten Kate, K. (2013). Biodiversity offsets and the challenge of achieving no net loss. Conservation Biology, 27(6), 1254-1264.10.1111/cobi.12118

Hanson, M. B., Emmons, C. K., Ford, M. J., Everett, M., Parsons, K., Park, L. K., … & Barre, L. (2021)

Endangered predators and endangered prey: Seasonal diet of Southern Resident killer whales. PLoS ONE 16(3): e0247031.[].

Hartman, G.F., & Miles, M. (1997). Jones Creek Spawning Channel: Post-Failure Analysis and Management Recommendations. Prepared for Fraser River Action Plan, Fisheries and Oceans Canada

Impact Assessment Agency of Canada (2020). Federal Review Panel Report for the Roberts Bank Terminal 2 Project. 2020, March 27  Registry Reference No. 80054. Retrieved November 12, 2020, from, 177-216.

Kehoe, L. J., Lund, J., Chalifour, L., Asadian, Y., Balke, E., Boyd, S. Carlson, D., Casey, J.M., Connors, B.,  Cryer, N., Drever, M.C., Hinch, S.G., Levings, C., MacDuffee, M.  McGregor, H.  Richardson, J. 

Scott, D.C., Stewart, D., Vennesland, R.G., Wilkinson, C.E., Zevit, P., Baum, J.K. & Martin, T.G. (2021). Conservation in heavily urbanized biodiverse regions requires urgent management action and attention to governance. Conservation Science and Practice, 3(2), e310.

Lacy, R.C., Balcomb, K.C. III, Brent, L.J.N., Croft, D.P., Clark, C.W., & Paquet, P.C. (2015). Report on Population Viability Analysis model investigations of threats to the Southern Resident Killer Whale population from Trans Mountain Expansion Project. Attachment E, Ecojustice – Written Evidence of Raincoast Conservation Foundation (A70286), National Energy Board (Canada). 120 pp. 

Lievesley, M., Stewart, D., Knight, B. & Mason, B. (2016). Assessing Habitat Compensation and Examining Limitations to Native Plant Establishment in the Lower Fraser River Estuary. BC Conservation Foundation. 

Quigley, J.T. and Harper, D.J. (2006). Effectiveness of fish habitat compensation in Canada in achieving No Net Loss. Environmental Management, 37: 351-366. 10.1007/s00267-004-0263-y

Vancouver Fraser Port Authority. (2021). IR2020-1.2 Proposed fish and fish habitat offsetting plan. 2021, September 24th. Retrieved December 13th, 2021.  

Vancouver Fraser Port Authority. (2021). IR2020-3 Avoidance and mitigation measures for project operation and marine shipping incidental to the project. 2021, September 24th. Retrieved December 13th, 2021.

zu Ermgassen, S.O., Baker, J., Griffiths, R.A., Strange, N., Struebig, M.J. & Bull, J.W. (2019). The ecological outcomes of biodiversity offsets under “no net loss” policies: A global review. Cons Let, 12(6), e12664. DOI: 10.1111/conl.12664

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