“Naturalness” and MPAs: Scientists Discuss Protection for Last Undisturbed Ocean Sites

When deciding where to site new marine protected areas, planners often consider the “naturalness” of a location – its relative lack of disturbance or degradation by humans. Reasons for using this criterion vary from economic to scientific, and from ecological to philosophical. In each case, the goal of these planners is to protect relatively pristine sites before significant human-induced change occurs.

But how much of the ocean still exists in a truly “natural” state? And how can resource managers protect pristine areas before human disturbance happens? This month, MPA News briefly examines the criterion of naturalness and the potential role of MPAs in protecting remaining undegraded sites.

Exploitation of natural ecosystems

Naturalness carries benefits. Relatively undisturbed marine sites may hold more economic value for fisheries or tourism than severely degraded sites, and may contribute more biological productivity to surrounding ecosystems (although some exceptions exist). Researchers often seek naturalness for their control sites, with which they can compare more-disturbed systems. Conservationists, particularly in western cultures, may want to capture naturalness for ideological reasons, including the belief that parts of the ocean should be allowed to exist outside of direct human consumption.

For the above reasons, one can open most any text on the planning of MPAs and see naturalness listed as a criterion for consideration. Although experts’ definitions for naturalness in the marine environment differ somewhat from one another (see box at the end of this article), each is usually worded to account for some level of human disturbance. Naturalness is principally a relative concept: Site A is more natural (less degraded) than Site B, although neither site exists exactly as it might have if humans were not around. In light of the presence of human-produced, water-borne pollutants throughout the world’s oceans, the growing impact of human-induced climate change, and large-scale fishing and whaling in the past century, the argument can be made that no marine ecosystem remains absolutely untouched by mankind.

The deep sea is where perhaps the least disturbed ocean ecosystems still exist. Distance from shore affords protection from land-based impacts such as the runoff of sediment and pollution, and great depths have made it difficult and expensive for extractive industry to capture seabed resources, such as fish or minerals. Nonetheless, the deep sea’s inaccessibility to industry is continually challenged by human inventiveness. Technological developments in the commercial fishing industry, for example, have allowed fishermen to locate and harvest catches in deeper and deeper waters. Trawlers in some fisheries operate at depths of 2 km. Notably, the decline of fisheries in shallower coastal waters has often spurred governments to promote deepwater fisheries as a way to sustain landings.

Once exploitation of a relatively pristine ecosystem begins, the impacts can be swift and significant. In the May 15, 2003, issue of the journal Nature, Ransom Myers of Dalhousie University (Canada) and Boris Worm of the University of Kiel (Germany) wrote that industrialized fisheries typically reduce the community biomass of exploited ecosystems by 80% within 15 years of beginning exploitation. Their analysis was based on communities of large predatory fishes in four continental shelf and nine oceanic – deepwater – systems. (Their peer-reviewed paper is available online in PDF format at http://fish.dal.ca/~myers/papers/Papers-recent/nature01610_r.pdf.)

“Management schemes are usually implemented well after industrialized fishing has begun, and only serve to stabilize fish biomass at low levels,” wrote Myers and Worm. “[O]n seamounts and on continental slopes, where virgin communities are fished, similar dynamics of extremely high catch rates are observed, which decline rapidly in the first 3-5 years of exploitation. We suggest that this pattern is not unique to these communities, but simply a universal feature of the early exploitation of ecosystems.”

In an interview with MPA News, Worm said it was necessary for managers to be more proactive in protecting natural areas. “It is paramount to avoid making the same mistakes in the deep sea – or on continental slopes, seamounts, or any other previously unfished spots – that we have made elsewhere,” he said. “On land, we are very proactive in protecting the last wildernesses from human impacts. We need to apply the same thinking to the ocean to safeguard what little is left.”

In Victoria, British Columbia (Canada), at a meeting last month of the Science and Management of Protected Areas Association, Daniel Pauly of the University of British Columbia said that for fisheries to be sustainable, managers needed to return to a concept that had previously protected fish stocks from human inventiveness. He called the concept “natural protected areas”: areas that humans could not, or did not, know how to fish yet. “Fisheries used to be seen as sustainable because there were limits to our ability – technologically or knowledge-wise – to get at the fish,” he said. “No-take areas are simply a return to that concept of limitation.” Without no-take areas, he said, human inventiveness in fisheries could not be managed effectively over the long term.

Pauly, who has published widely on the global state of fisheries, is skeptical that resource managers will achieve the proactiveness necessary to protect most of the still-existing natural protected areas before exploitation occurs. Although seafloor ecosystems deeper than 3000 meters may remain safe, he said, many pelagic fishes over the deepest sea are overfished, as are most shelves. “Hence, most governments can now only re-establish ‘protected areas’,” he said. He estimated that unique ecosystems off the British Columbia coast – including deepwater sponge reefs – would be destroyed by fishing activity “within a decade or so” if protective measures were not taken soon.

Finding the natural areas

Glen Jamieson, a scientist with Canada’s Department of Fisheries and Oceans (DFO), has studied those sponge reefs and is working to preserve them. The reefs that have been located so far, at a depth of 200 meters, are already protected by trawl closures, instituted last year (MPA News 4:3), and DFO is considering them as candidates for broader protection measures under the nation’s Oceans Act. Discovered just over 10 years ago, they are the only known examples of living Hexactinellid sponge reefs in the world.

Jamieson says there is much that remains unknown about these sponge reefs and other unique assemblages of living resources in Canada’s Pacific waters, including deepwater corals. “All the probable areas where the sponge reefs may occur have yet to be fully surveyed and mapped,” he said. “As for corals, we have not yet determined all the large coral species likely present in these waters. There are older anecdotal reports from fishers of corals as bycatch, but areas where corals occur, or may occur, again have not been surveyed scientifically.”

In light of the delicateness of these structures, their age, and the likelihood that they could be degraded by certain fishing gears if not protected, Jamieson said he would like to see DFO more actively seek out these sites and protect them before significant extraction occurs there. First, he said, DFO needs to identify areas where corals or sponges occur in quantity, based on logbook bycatch records or research-survey sampling. “Then we could identify the particular oceanographic and substrate features associated with these areas to determine the optimal habitat conditions for these species,” he said. Based on this knowledge, researchers could identify high-priority areas for surveys. To date, he said, such research has not received the priority and funding necessary to perform it.

“There is some urgency to this issue,” said Jamieson. “Corals and sponges may ultimately recover on damaged habitat, but this may take centuries. In the meantime, ecosystem function may be lost.”

On the Atlantic coast of Canada, Derek Fenton of DFO has looked at naturalness as one consideration in protection strategies. Last year, as part of an initiative to inventory and map various marine activities in support of integrated management efforts, Fenton examined spatial trends in fishing offshore of Nova Scotia. Applying aggregated logbook data from the past decade to a grid, he mapped the presence or absence of all types of fishing and the level of activity. Although finding non-fished areas was not an explicit intent of the exercise, he took notice of such sites, which appeared as white spaces on his maps.

“Most of the offshore is fished to some extent by either groundfish, invertebrate, or pelagic fisheries,” he said. “However, many deepwater areas and several areas on the eastern portion of the Scotian Shelf had a number of large white spaces.” In fact, several areas of up to 1000 km² showed little or no fishing activity of any type. Although the low activity in most of the areas can be explained by the presence of fishery closures or physical inaccessibility to some forms of bottomfishing (i.e., deep holes and complex topography), the low rates of activity in other areas needs further investigation, he said. Some of the sites may simply not be traditional fishing grounds, or have a low abundance of target species. Overlaying these maps with ones showing other resource uses, he found that some of the non-fished areas also displayed little presence of other human uses, such as petroleum production, which is increasing in many areas of the Scotian Shelf.

Such areas where little or no human activity is occurring could provide resource managers an opportunity to protect these parts of the ocean without inflaming public opinion or opposition. This is the “low-hanging fruit” concept of resource conservation: start by protecting the easiest sites first. (Fenton stressed that the mapping conducted on fishing activity was very preliminary and not indicative of any plans by DFO to seek MPAs in the low-activity areas he found.)

Fenton recognizes that just because there is no activity at a site does not mean that it warrants designation as a protected area: there may be nothing there “worth protecting” in some people’s view. Furthermore, any candidate site would still need to meet the purposes for protection outlined in appropriate legislation, he said. Nonetheless, these relatively natural sites may hold interest to the scientific community as reference areas. In the future, Fenton would like to refine the identification of these low-activity areas and explore their role in conservation planning.

For more information:
Boris Worm, Institute for Marine Science, Duesternbrooker Weg 20, 24105 Kiel, Germany. Tel: +49 431 6004407; E-mail: bworm@ifm.uni-kiel.de.

Daniel Pauly, Fisheries Centre, University of British Columbia, 2204 Main Mall, Vancouver, BC V6T 1Z4, Canada. Tel: +1 604 822 1201; E-mail: d.pauly@fisheries.ubc.ca.

Glen Jamieson, Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, BC V9R 5K6, Canada. Tel: +1 250 756 7223; E-mail: jamiesong@pac.dfo-mpo.gc.ca.

Derek Fenton, Oceans and Coastal Management Division, Bedford Institute of Oceanography, Department of Fisheries and Oceans, B500, 5th Floor Polaris, P.O. Box 1006, Dartmouth, Nova Scotia B2Y 4A2, Canada. Tel: +1 902 426 2201; E-mail: FentonD@mar.dfo-mpo.gc.ca.

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