Thank you. Good morning.
First of all, I believe it's World Oceans Day, so congratulations. I believe Canada started that, so it's an honour to be here on this day.
I don't actually work on marine protected areas. In fact, I've been studying the physiology of sponges in a marine protected area. I've read some of the statements from the previous witnesses to this hearing, so I believe perhaps the area I can comment on is the Hecate Strait and Queen Charlotte Sound marine protected area, in which I work. In particular, I can comment on the science that goes into determining boundaries.
To provide some background on that habitat and that marine protected area, the first slide shows an image from the website of Fisheries and Oceans that indicates the locations of the three reef complexes on the west coast of British Columbia.
I've been studying glass sponges since 1991 and sponge reefs since 2004. Glass sponges are deepwater marine animals that are very unusual. They're unusual in many ways, not the least of which is that they have a pure glass skeleton—completely opal. Unlike corals, they lack nerves, but they have an electrical signalling system that makes them sensitive. This is my particular interest. The sponges filter water—a lot of it. They do this by using whip-like cells that suck the water through themselves. I give you this just as a bit of background as to the kind of creatures that are forming the habitat we're talking about. This can be seen: if you put dye on the wall of a sponge, it draws the water through itself.
They filter a lot of water. We generally say that a sponge filters 1,000 times its body volume each day, but that can vary. As with any pump, it's costly. The cost of balancing how much energy it takes to filter the water and how much energy it gains from the water is what I'm interested in, and this is what we need to know in order to understand why reefs can form where they are.
A single sponge like this one in Hecate Strait, which has an opening the size of a dinner plate, can filter 300,000 litres of water a day. That is six times the size of this water tank, which is 50,000 litres. That's a single sponge, and there are multitudes of these across the reef. We've estimated that where sponges are dense, they can filter the entire water column—170 metres—each day.
Of course, water moves, and new water moves in at each tide to replenish what they have filtered. Sponges extract bacteria from the water and excrete wastes as ammonia and as particles. The ammonia is reused by phytoplankton, and the particles are eaten. We call this an ecosystem function.
Sponges are stationary animals, and the reefs have thousands and thousands of sponges. In this video, you can see that the multitude of animals that make up this reef live among the sponges. There are rockfish, crustaceans, and huge numbers of different invertebrates. I've been working in other reefs, but in Hecate Strait in particular, we see rockfish in every single crevice. These are juvenile rockfish, so it looks like it's a very important habitat for juveniles.
The Hecate Strait reefs were an obvious target or area of interest for a marine protected area. They're globally unique. These structures are not found anywhere else in the world. They work as a nursery, and they have this ecosystem function of filtering water, but it still took many, many years for them to become a protected area.
They were first found in 1989. In 2009, consultations began to make them an area of interest, and in 2010, they were formed as an area of interest. In 2012, I was asked to join a trip to verify the areas where the reefs occurred. They had discovered potential new areas by mapping, so we travelled to look at this.
In 2013, I was asked if I would provide some evidence or science on the effect of sediment on the sponges. This spurred a collaboration between me and Fisheries and Oceans colleagues funded by pockets of money that were made available for these kinds of collaborations. We leveraged more money by getting NSERC-funded ship time grants to get out to the reefs. In the last four years, we've had two trips. I returned from the last one three weeks ago.
In that work, we did experiments to look at the effect of sediment on the sponges and found that when you resuspend sediment over the sponges, it does, in fact, coerce them to stop filtering, to stop pumping. It takes them about an hour to recover after each sediment burst. We also checked the predicted boundaries of the reef and we can say that, while they're very accurate from the multibeam, they do overflow by about 10%.
This slide shows the northern reef complex. The blue area on this slide is the area outlined by the area of interest in 2010. In yellow is the core protection zone, and in grey is the adaptive management zone. The area of interest, you can see, is slightly larger than the core protection zone. The core protection zone and the adaptive management zone come from the Canada Gazette and they come from the 2015 publication and have not changed. Clearly what's happened is the core protection zone is slightly smaller than the area of interest.
We have found that in the adaptive management zone, you potentially could have a trawling fishery, but currently it's closed on the precautionary principle. Since we found that sediment does affect the sponges, their filtering, it would seem that's an accurate supposition. We found that they stopped filtering when levels reached 10 to 40 milligrams per litre. That's a quarter of what's suspected to be or known to be resuspended by trawl fisheries, and we know from very thorough studies that trawl fisheries do elevate sediments up to 800 metres behind the trawl.
The adaptive management zone shown here is about 600 to 1,200 metres. There is no scale on this figure here, but with the blue line that you see, the distance between the blue and yellow is about a kilometre. What we're looking at is an area around this reef that is probably fairly good as a buffer zone if no activity were to occur in it.
Another thing to know is that in this reef we have a vertical adaptive management zone. That means fisheries are allowed to trawl above the reef at 30 metres, so mid-water trawling. In 2013, the Canadian Science Advisory Secretariat reported that 13% of mid-water trawls had some benthic species in them that indicated the trawl might have touched the bottom. They weren't sure if those were transcription errors in the database, but 13% of 115 trawls is about 15 errors. The question would be that if the trawls did touch the bottom, considerable damage might occur.
I took the liberty of bringing with me a piece of the sponge that we collected at Hecate Strait, which I can show you to indicate how fragile these really are. I don't do this to say this is a very remarkable creature, it's just that a single trawl would definitely ruin this. We have done experiments to look at the recovery of the sponges, and they do not recover after five years. Again, the precautionary principle might be used.
I read some of the transcripts from the earlier witnesses and I understand that people felt there might not have been enough consultation and that the precautionary principle might not have been used perhaps fairly. I feel that if you look at the recording of the Canada Gazette it actually reports quite a considerable amount of consultation. What seems to be the case is that people may not be quite aware of all the science that has gone into the decision-making at each stage of making the boundaries. That seems to me to be quite a simple thing, because even I have trouble understanding exactly how these boundaries were formed.
It might even be simply a case of making the science and the decision-making available on a website and making the timelines in which those decisions were made readily available, as the minutes to these meetings are, so that people are very aware of those decisions.
Thank you.