First, let me thank you for the opportunity to share my thoughts on the scientific rationale for both the uses and the design of marine protected areas as conservation tools for marine ecosystems and species, as well as the human services that those species and ecosystems support.
I've been studying, publishing, and advising on marine protected areas—which I'll refer to as MPAs from here on—since the late 1980s. For eight years, I co-chaired the science advisory team for California's Marine Life Protection Act, which created a network of marine protected areas along the entire 1,300-kilometre coast of California, and it also created the largest science-based network of MPAs in the world. That process also contributed to the creation of design criteria for MPA networks, many of which are currently being proposed for networks on both the east and the west coasts of Canada.
I currently sit on the U.S. Marine Protected Areas Federal Advisory Committee.
While I appreciate the opportunity to convey the rationale for protected areas, I want to keep this as brief as possible so that we have plenty of time for questions. I also understand that the presentation I am going to give tomorrow at the Oceans20 MPA workshop will be made available to you as well, and it goes into greater detail on some of the aspects of this testimony.
There are two types of MPAs that have emerged over the past decade: really large MPAs, in the order of hundreds of thousands of square kilometres, which are located in very remote places with very little human activity; and then networks of smaller marine protected areas that are embedded along working coastlines and seascapes. While those networks of MPAs are smaller in overall area, they provide greater conservation value because they occur where people are using the ocean, and they foster a higher likelihood of contributing to the sustainability of coastal fisheries. Therefore, my comments are all going to be focused on this idea of networks of protected areas.
These networks of protected areas offer unique opportunities for the conservation of Canada's marine biodiversity and the ecosystems that maintain that biodiversity. That's because, like protected areas on land, they protect entire ecosystems—in many cases multiple ecosystems—rather than just a particular species. By encompassing an entire ecosystem—say, an estuary, a kelp forest, a deep rocky reef—they protect not only the species that inhabit that ecosystem, but also the important interactions among those species, and then the productivity and the services that marine ecosystems generate.
Those ecosystems interact with each another in two fundamental ways. The first is by the movement of organisms between ecosystems. For example, many fish species that live in deeper offshore habitats will migrate up into shallower ecosystems to spawn, or their young will use those shallower ecosystems as critical nursery habitat from which they will eventually come down and replenish adult populations.
The other is the movement of energy and nutrients from one ecosystem to another. For example, winter storms will dislodge kelp plants. Those kelp plants, and the energy and nutrients associated with them, will be carried either to onshore ecosystems or to offshore ecosystems, where they will fuel the productivity of those ecosystems as well.
By including multiple ecosystems in a given MPA, you protect not only the species that inhabit those ecosystems, but also the critical interactions between ecosystems.
However, MPAs differ from protected areas on land in one fundamental way. When land animals and plants reproduce, the young remain near their parents in the population that created them. They create self-replenishing populations. That means that you can maintain a self-replenishing population within a protected area on land, but it contributes very little to the conservation of those populations beyond the boundaries of that protected area.
In strong contrast, the young that are produced by most marine species are carried tens to hundreds of kilometres away from their parents by ocean currents. That has two fundamental implications for the use and design of marine protected areas. First, it means that the populations within a protected area are reliant on the young that are delivered to them, but produced somewhere other than that protected area. The implication is that if you space these protected areas from one another by the distance that those larvae travel, that means that the young produced in one protected area can help to ensure the replenishment of populations in another protected area.
Importantly, at the same time, they also replenish the populations in between those protected areas. They replenish fished populations as well. As a consequence, the conservation value of a marine protected area extends well beyond the boundaries of any one protected area. The area over which the young that are created in a marine protected area contribute to the replenishment of other populations is determined by just how far those larvae are carried by ocean currents.
If you take one large marine protected area and parse it into smaller areas along the coastline separated by that distance that the young disperse, what you've done is blanket the entire coast with young that are produced by those protected populations in the marine protected areas. You not only increase the area of conservation, but you also increase the replenishment of fish populations by distributing protected areas along the coast in a network.
By encompassing multiple ecosystems within each MPA, thereby protecting the interaction between ecosystems, and by spacing those protected areas at the distance that young disperse, you actually create one of the most robust conservation designs for marine protected areas. This is why this idea of networks is proposed for both the east and west coasts of Canada.
I hope these comments have helped clarify the scientific rationale for why the idea of networks of protected areas is so popular.
Again, thanks for the opportunity to try to explain that.