NPR/NGS Radio Expeditions
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Log: AC interview of Dr. Ken Sherman
:40 KS My name is Ken Sherman I work with the National Marine Fisheries Service. I do work on large marine ecosystems, and deal with the interaction between fisheries and their ocean environment, and fisheries and people who use fish for economic purposes: fisherman and people dealing with other marine resources other than the sort of ordinary fish we know about, but people who are interested in marine algae, seaweeds, um, invertebrates, organisms living on the bottom. We actually have an interest in the wide spectrum of living marine resources in the populations that constitute these resources.
AC 1:35 When you say fishery -when people use the word fishery, what do they mean?
KS 1:39 They generally mean an activity that has an economic end result, in contrast to a more scientific perspective which would have to do with the actual demographics of the populations that constitute the resource.
AC 2:01 OK. Those were just little things to start with.... Describe if you would the northeast shelf ecosystem. When you call that great area a northeast shelf ecosystem what exactly do you mean. What is it?
KS 2:21 Well, off the coast of the United states we are very fortunate in having very productive coastal waters. Not all coastal waters are identical. They have distinct characteristics and they can be separated on a regional basis on their natural productivity, on the bottom contours -a criteria we call bathymetry -and in the nature of the interaction between the water column itself and the current, something we refer to as hydrography, and then the linkages in the food chain between the various components in the food chain: plankton, fish, marine mammals, marine birds. There are distinct associations around the U.S. and in observing these distinct associations we've been able to apply scientific ecological criteria and have divided the area into seven large marine ecosystems and they extend pretty much over two hundred thousand square kilometers -each of them. And then in the northeast, we have an area that extends from Canada to the North and to Chesapeake Bay, and the South and from inshore to about two hundred miles off shore. And we refer to this as a distinct large marine ecosystem and we simply use the description of northeast continental shelf ecosystem for this region.
AC 4:03 You say that there are seven of these regions that layoff the coast of the United states?
KS 4:08 Yes, that's correct.
AC 4:10 Are these different regions that you could see on a map? ..
KS 4:24 Yes, we actually have actually over the past ten years atlas projections of these areas. And the one I just described briefly is the northeast shelf ecosystem from Chesapeake Bay to the Florida straits we have another distinct system that we refer to as the southeast shelf system. Adjacent to that is the entire Gulf of Mexico as a large marine ecosystem. On the west coast we are looking at a very broad area off the coast of California referred to as the California Current large marine ecosystem. And the area to the north of the that off the coast of Washington and Oregon is the Gulf of Alaska large marine ecosystem. And
just to the north and west of that is the Bering Sea ecosystem, and out in the central Pacific we look at clumps of Ireland as insular large marine ecosystems and the one that we are most interested in in this country is of course the Hawaiian Islands as an LME, large marine ecosystem.
AC 5:31 NOW, did you come up with this idea of these large marine ecosystems? Because I haven't -these are not commonly -people don't think that there are geographical demarcations off the coast of the -we don't think of that as something that's applying to the ocean, we think of that as something for land.
KS 5:49 Yes, that had been the traditional way to sort of look at things, but as the stresses from growing coastal populations have increased in the utilization of marine resources, fisheries in the losses of habitat in the increasing coastal pollution it has become evident that we need to move forward in how we order our priorities in how we dealing with these very many problems, and we found over the past ten years that they are inter-related; they are not distinct problems ... In fact from a scientific point of view we have come to the conclusion that their problems associated with large marine ecosystems, and hence over the last ten years there is greater interest in these distinct areas in not only assessing and monitoring change within those systems, but considering them as units for management for long term sustainability of the resources within them.
AC 7:01 And that's because all of the things that live in these ecosystems are related to one in other -they depend on one in other? They all
**KS 7:11 That's exactly right. For example off the northeast shelf of the fish that is utilized for fisheries -commercial fisheries and recreational fisheries purposes -just to give you an example of this inter-relationship of all of the fish produced off of that northeast shelf 70% of them are being consumed by other fish and that leaves 25% of these fish available for other consumers in the system -in the natural system. 10% are consumed by marine mammals, 10% by large sharks, 5% by birds, and there is 5% left over for human use, and that's what our fisheries economy is based on. So here we have this very large number of 70% of that production being consumed by large fish eating smaller fish.
AC 8:11 Well, you know, people talk about overfishing and the Georges Bank
is being closed for fishing, and we blame human fishermen, not birds and
sharks and other fish.
KS 8:26 Well, I think it's not a question of blame, it's a question of looking at the facts that we have available to us from some thirty years of studying the system, and the conclusions that we have reached. In the case of the northeast shelf ecosystem it's clear that 5% that's being utilized for supporting the commercial fisheries and recreational fisheries that ¬those populations are no longer able to sustain themselves in that we are catching far too many of the adults and not sufficient new generation is being produced to support the fishery. For those species that are very
desirable. That's not to say that the ecosystem is unhealty. Quite the contrary. Off shore it's quite a healthy ecosystem with the capacity to produce other kinds of fish so as we deplete cod and haddock and flounder what we have observed is that other species that are less desirable from an economic point of view have virtually exploded and their populations are at historic, unprecedented high levels. And the two species in particular worthy of mention here are mackerel and herring. They are at very high levels of productivity just now.
AC 9:57 Are you saying, Dr. Sherman, there's no crisis in the ocean?
KS 10:02 No, I am not saying that. I am saying that there is a very severe economic crisis off the northeast coast of the u.s. because the most desirable species, those that are the basis of the fishery in New England are in an extremely depleted state. At the present time there is no market, no high value for the herrings and for the mackerels so that we have a severe economic crisis and we have fisherman being displaced from fishing because of the extreme situation where it is necessary to in fact close the fishery to allow for the recovery of these depleted stocks for which the public has a great demand -cod, haddock and flounder.
AC 10:57 But if people liked mackerel and herring everything would be fine.
KS 11:00 If people liked mackerel and herring, and if ah the market response was to put a value that was commensurate with the effort for catching them I think that would mitigate some of that economic displacement that we are facing just now.
AC 11:21 Let me just ask you something slightly different. Imagine that we're going from Mt. Washington due east, you get -you come down out of the White Mountains, and you get down to the coast line there, and you head out into the water...What happens to the topography when you go -when you splash?
THE FOLLOWING DESCRIPTION IS INTERESTING BUT DOESN'T DIRECTLY APPLY TO THE ECOSYSTEM...
KS 11:52 Yeah, that's an interesting question, and in fact, the topography is not significantly different. We have the same sorts of plateaus, valleys, and eh sort of uneven topography with not quite the dimension of the White Mountains, but similar to the White Mountains, as one continues off from the coast of Maine that rugged topography is also found at the ¬- along the bottom of the Gulf of Maine.
AC 12:26 So its not just covered with sand and flat.
KS 12:30 No, it's not flat at all. In some places there's sand, other places gravel, other places mud, other places steep slopes, channels. The same sort of topography that we see on land is indeed found off the
northeast shelf in the northern area. As one moves south, that is south of Cape Cod, there is the more classic bottom that you maybe referring to, which is a gentle sloping, sandy, muddy bottom off to the edge of the continental shelf where there are irregular fairly dramatic deep canyons.
AC 13:09 And they -You.....You slope out to the continental shelf, and how far does it take get there?
KS 13:22 Generally, off the northeast coast of the u.s. about 150 miles.
AC 150 miles? And then what happens?
KS And then there is a steep slope that moves off from what might be 300 meters depth to ah 1500 meters depth. There there is a distinct change in the bottom topography.
AC 13:49 You are talking about a mile deep.
KS 13:50 Yeah, off into the deep ocean basin.
AC 13:55 You know on land the most -on land there are two dramatic topographical features. There's are mountains and there's rivers. Underwater, what are the dramatic topographical features that you would notice?
KS 14:16 Well, underwater you would notice -if you where in a submarine, captain Neimo's submarine, and looking out through the porch, you would notice the same kind of bathymetry -smaller mountains, valleys, hills and some plateau areas mixed in.
AC 14:37 You use that word bathymetry. What is that?
KS 14:39 That is the sort of -It is a geological term that simply refers to the contours of the bottom; the bottom of the ocean.
AC 14:48 So, you are simply saying that you see small mountains and hills -
KS -and valleys, yes indeed, and these are extremely important for the biologically populations in that they've adapted spawning and feeding migrations in response to ocean currents and the order mass itself, which moves over the bottom and through the water, and the velocity and direction current patterns is to some degree a response to the irregular bathymetry ¬irregular bottom topography.
AC 15:28 The shape of what the sea floor looks like.
AC 15:32 ...Are there fish that like a particular kind of topography underwater.
KS 15:40 Yeah, there are habitats underwater to which fish have adapted strategies for reproduction. For example the herring that we spoke about before seeks out broad, relatively flat areas that are gravelly bottom, and they deposit sticky eggs which remain on the bottom. The gravelly bottom is indicative of places where there is fairly vigorous current. And where there is fairly vigorous current there's a lot of mixing of oxygen and this of course is important to developing embryos with in those eggs and provides them with a good beginning of life. When they hatch, then these
baby herring move up to the surface layers, where they can feed on the plankton. So there's a definite spawning characteristic related to bottom topography for that -that particular species.
AC 16:56 In your large marine ecosystem concept, and the boundaries that you've drawn -is this something that scientist allover the world have come to agree upon, or are these boundaries that you have drawn -something someone else would say, oh no, it should be 500 miles north of there or something. I mean is this commonly excepted?
KS 17:21 We don't yet have full acceptance by all scientists, but we do have an evolving concept. As a concept has been a growing degree of acceptance that the world can be divided by these large marine ecosystems. The exact location of boundaries will be subject to discussion over the next 10 or 20 years, but the concept is -has now been established over the past ten years by not just myself, but hundreds of scientists that have participated in national and international workshops on the causes for the changes in the habitats, in pollution levels, and in the actual yields of fisheries coming out of those systems. So they are very practical reasons why these divisions have been attractive not only to the scientists, but to the managers of these resources.
AC 18:29 There is something in it for us to look at the ocean this way.
KS 18:34 Yeah. I'd say something in it in a very significant way; and one for which in '92 we passed a very significant milestone with that meeting down in Brazil called UNSED. The United Nations meeting down in Brazil for the development of resources, where we had the representatives presidents of some 160 nations assigning declarations for a variety of environmental
issues, one of which is associated with the oceans... From that time on we passed a milestone of looking at isolated species into a decade where we are now looking at species interactions in -against ecological backgrounds, both terrestrial and marine. So that the concept of large marine ecosystems has been supported with these declarations at the UN conference of Environment and Development. Furthermore, much of the development particularly in the last five years has been supported by
international agencies amongst which the World Bank has provided large amounts of funding, in the areas of 2.8 billion dollars to address environmental issues as developing countries seek ways to utilize the resources in the oceans off their coast, but in an environmentally sensitive manner. So I think that this is a very positive development for which these large marine ecosystems provide some means for moving forward.
AC 20:37 I just want to go back and touch on something that you talked about before, and that is the various populations on the Georges Bank and the fact that humans account for only 5% of the take of the fish. You are talking about gross numbers of fish of all species taken from the ocean it maybe a little confusion for people, are you saying that the basic ecosystem in the ocean is healthy now?
KS 21:11 Ah -Well, I guess I would say for the open ocean areas, for the areas away from population centers, away from the continental shelves, and away from immediate coasts. I would say that the scientific literature would support a statement that one could make indicating that most of the world's oceans are in a fairly healthy state -but that's a geographic extent. However, one would have to follow immediately with a statement that the near coastal areas, the areas where these large marine ecosystems have been designated, essentially the areas between 2 miles to 100 to 200 to 300 miles off the coast of all of the continents it's those areas which represent relatively small geographic area in the world ocean. Never the less from an economic and social view they represent our greatest interest, because 95% of the fish produced in the ocean on an annual basis that are utilized for commercial and recreational purposes are produced within that highly productive coastal zone. It's also the area that's subjected to a lot of the industrial and human wastes and is subjected to increasing levels of pollution, and even more important to very extensive loss of habitat to industrialization so I would say that we have very severe problems in the near coastal and in some cases we can advance our understanding about how severe these problems are by comparing one large marine ecosystem and its state against another large marine ecosystem and
its state. For example a place that's semi-enclosed like the Black Sea is a classic example of a large marine ecosystem that's under extreme stress from coastal pollution, from the drainage basin of the Danube flowing into the Black Sea for the past 50 years carrying with it toxic wastes and nutrient over load. So, in the Black Sea we have an example of an area where the biodiversity is very much reduced where the fisheries have been more or less depleted, and where jelly fish have taken over as dominate members of the ecosystem. This is an extreme case, but from this case we can learn that one does need to deal with mitigation of the stresses that we have in these coastal ecosystems. 24:15
end of interview.