GA: Watching MSX moving along the eastern seaboard, what have you observed about the progress of this disease and how it is affecting the industry in both its farmed and wild oyster components?
MM: I was not expecting MSX to be found in New Brunswick in year 1 [2024, the year MSX was first detected in Prince Edward Island oysters], and I think it’s fair to say that many of us were dismayed to see the rate at which infections were confirmed outside of the initial area. It is certainly complicating transactions within the industry, but the real worry is around the high mortalities, which are being observed in certain wild populations.
GA: Is the use of wild spat still possible or is it becoming too risky for the spread of MSX?
MM: Wild spat can be infected in its first year of collection, as has already been demonstrated, so it is unlikely that wild spat collected from high-prevalence areas will be a valid option to transfer to low-prevalence areas. Local collection of wild spat will likely be a viable option in the short term, but we expect a large shift towards MSX-resistant strains once they become available.
GA: What techniques have ERB been using to safeguard its operations against the advance of MSX? More specifically, how do you select disease-resistant strains now?
MM: We already have a selective breeding program in place, which is a necessary launching point for any serious attempt to breed resistance. We are reorienting our program now to incorporate MSX and Dermo (another disease challenge for oysters) resistance and will be starting field trials in summer 2025. Broadly speaking, the goal is to identify genetic variation that is associated with disease resistance/tolerance, then make sure our breeders possess that same genetic profile.
GA: Will these techniques be enough to withstand the disease or do you and other producers need more and better strategies?
MM: Selective breeding is widely considered to be the only viable long-term strategy to ensure a viable production of oysters in the face of these diseases. In the interim, oysters growers are creative and may devise a number of different ways to mitigate the effects of diseases whether it be through relay, improved husbandry, or something entirely novel!
GA: What are the biggest challenges in combatting MSX in your hatchery operations today?
MM: At this moment, the biggest challenges for us are logistical. The regulatory environment is changing rapidly, and we are adapting to meet them and ensure our clients are still able to purchase seed.
GA: Are you looking at genomics as a potential solution? Could it be used to develop an MSX-resistant oyster, and if so could the process build on your prior use of genomics-based selective breeding to obtain a Canadian oyster strain from the Eastern oyster?
MM: Genomics is key to our breeding strategy. By employing genomic tools we hope to greatly accelerate the process of selecting for resistance, especially in our facility where breeding survivors would not be an option due to our disease-free status. We are building both on the tools we’ve built but more importantly on the team and our collaborators who are now as passionate about oysters as we are!
GA: Would it be costly? How long would it take? Does that kind of solution interest Maritime growers?
MM: The development of new genomic tools is not cheap, but once they are established it is within the price range where sufficiently scaled operations can incorporate their use into their regular activities. At this point, it is really not much of a choice: we either adapt to this new situation with every tool at our disposal or we risk losing what we’ve built without a fight.
GA: How much time do you think the industry in the Maritimes has to fortify itself against the full effect of MSX?
MM: It is definitely a race against the clock: if we’re lucky we will have at least partial disease resistance before the worst effects are widespread. Guessing a specific timeline would be difficult, but we are hoping we have a few seasons.
GA: In your estimation, how severely have P.E.I. stocks been affected by MSX? How long do you estimate it might take to restore MSX-free oyster stock on the island?
MM: Certain populations, for example in Bedeque, [Prince County, P.E.I.] have already seen widespread infection and mortality. In many others, the prevalence appears lower, which is probably reflective of more recent introductions. For the moment there does not appear to be widespread mortality throughout PEI but the full extent of the effects will only be known in time. Most examples we have of selective breeding for resistance seem to point to approximately a 2-3 generation interval to develop an appreciable amount of resistance (about 4-6 years), which we hope to accelerate using genomic tools.
GA: What do you need from government policy makers to help the industry survive the MSX threat?
MM: We need a more flexible and responsive regulatory apparatus, especially, which takes the realities of the industry into consideration. Already we have encountered several situations where existing regulations simply don’t make sense in the context of the reality of oyster aquaculture and the aquatic environment, especially with regards to transfers. Many growers will face financial hardship as the result of this situation, and we need to ensure they are able to weather the storm.
GA: What advice do you have for others in your industry facing this challenge?
MM: There’s considerable uncertainty right now, but the experience in other areas shows us there is a future for the industry through resistant oysters, so there’s reason for optimism.
