TRANSCRIPT - Dr. Steven Murawski
Murawski is chief of Population Dynamics Branch at the National
Marine Fishery Service in Woods Hole, Massachusetts.
The collapse of the cod fishery is probably the biggest news in
the world for fisheries collapsing. Can you fill us in about the
history and the consequences of the collapse?
The cod fishery,
and actually by analogy the cod and haddock and pollock and other
ground fish species, have undergone a tremendous change in abundance
off the Northeast United States. But thats symptomatic of
a larger problem, certainly in the Northwest Atlantic. Traditionally
weve identified up to a dozen different cod stocks in this
region and theyve all had basically the same fate over the
last couple of decades. They all went through a period of heavy
exploitation by distant water fleets, when the Soviet fleets and
others came in the early 60s.
and United Stated extended their jurisdiction to 200 miles and booted
out the foreigners, and weve both gone through a period of
domestic over-fishing, which have left a lot of the ground fish
stocks in our regions at very low levels, with very poor expectations
for short-term recovery. And I think were beginning to understand
not only the dimensions of these problems economically, but also
ecologically, which have been very dramatic.
The basis for
all this is an over-fishing scenario where were extracting
at far too high a rate given the natural productivity of these stocks.
And as we start to get a handle some of these over-fishing problems
and try new ways of regulating these species, we can start to see
responses that give us more certainty that underlining root
cause of these declines was in fact over-fishing.
Why is cod such a prolific fish and how long do you think it will
take for stocks to rebuild?
we have to mention the haddock here in the northeast region because
historically its been such a dominant species have
really gone through a tremendous period of boom and bust, in terms
of the stock sizes and also the landings the fishermen have taken.
Back at the turn century and for the first two or three decades
of this century, landings of haddock really rose tremendously, as
people like Clarence Birdseye came up with new ways of processing
these things and filleted fish went, not only in New England but
throughout the whole country.
rose very quickly as new modern fishing technologies, like the auto-trawler,
were introduced into our fisheries. And we saw landings going up
to well over 100 million pounds of haddock per year. And that was
sustainable for several decades, from the 30s to the 1960s.
But the addition of this tremendous amount of fishing effort by
the foreign fleets, plus the addition of new and improved technologies
that was more able to catch the fish really sent the harvest rates
of haddock and cod and other species to levels that were totally
harvest rates of those stocks in the early 1990s were on the
order of 60% per year. That means for every ten fish of adult size
in the ocean six were taken out by fishing. If we assume that two
of those die of natural causes that only leaves two left over to
reproduce, out of that original ten, and thats far two few.
For ground fish species like cod and haddock and others, an optimal
rate of harvest would be two or three out of ten per year. And that
would give us a nice broad age composition of spawners; that would
give us a lot of reduction in year-to-year variation because were
leaving species in the ocean that will generally survive there.
were originally very slow to react to the high-quality scientific
information that showed the declining trends in abundance
the declining trends in production of juveniles which are going
to support your population two, three, four years down the road,
and also this increase in the exploitation rate, the harvest rate,
the fraction of the animals taken out per year they were
very slow on the switch. And because of that reason we did long-term
damage to these stocks. The recovery rates of these things are slow.
Generally speaking they dont start reproducing til theyre
two, three, or four years old. Under natural conditions, without
high harvest rate, they have life spans of fifteen or twenty years.
Cod and haddock
and other species in our region are relatively long-lived, but without
the effects of fishing we can see the animals living up to 15 to
20 years old, reproducing every year after the first year they start
to spawn, which is age two or age three. This gives us a big buffer
in these populations that are naturally subjected to a wide degree
of climate variability because of the place we live in. These are
good buffers for sustainable fisheries by leaving a broad age composition,
and that occurs when you have low harvest rates. With harvest rates
of 60% per year you cannot have a sustainable fishery on things
Please elaborate on why different age groups are important to recruitment.
For an animal
like cod, where theres a lot of year-to-year variations in
the marine weather, if you will, you need to have a broad grouping
a broad distribution of age groups in the spawning population
and thats important for two reasons. Number one, what
we found in a lot of laboratory studies, in a lot of ecological
studies out in the ocean, is that the older and more experienced
females are better at spawning in terms of the survivorship of their
young than the first-time spawners. And by fishing at a high harvest
rate we concentrate all of the spawning in the first or second time
spawners and the success rate is low; its like having a whole
population of teen-age mothers, as opposed to having a good, broad
distribution of everyone spawning. And these are hard-won lessons
in terms of looking at fish populations and managing them.
Where do you think we stand with scientific data and research on
the subject? Do you consider it still to be in its infancy and still
got a long ways to go?
When you think
about it and step back a little bit, we have a task that is literally
of Biblical proportions were trying to count how many
fish are in the sea. These are large areas in the northeast
region were trying to look at codfish and other species over
a quarter of a million square kilometers and trying to index their
trends and abundance and the factors that affects their survivorship
and the effects of fishery regulations. Those are difficult spatial
problems. Those are difficult problems because the critters that
were interested in hide from us theyre under
the water; theyre hard to find; theyre hard to catch.
And thats why weve put in sampling regimes that are
trying to maximize not only our ability to go out and hunt these
things down with research vessels, but also gathering every scrap
of information we can from commercial fisheries, from scientifically
trained observers that ride fishing boats, et cetera.
We have put
together sophisticated population models that put these data sources
together and try to make a unified picture of whats happening.
This is happening all over the world, where people are trying to
get a handle on whats going on in the marine environment.
Its difficult. Its expensive; if youre dealing
with deep water and far from shore, its very expensive to
mount the types of efforts that you need. But when you look at the
value of fisheries, both in the United States and worldwide, theyre
so valuable, not only in terms of economic dependency but also jobs.
The amount that were actually spending on research is infinitesimal
relative to the value, on an annual basis, to this resource.
Do you have
anything to say to fishery managers worldwide on how to contend
are not unique to fisheries management. In almost any natural resource
problems we see worldwide, be it forestry or range management, these
are the kinds of local level issues that we get involved in when
basically were trying to regulate a population thats
fishing on resources that are the publics resources. These
are very understandable confrontations that we get into when were
trying to basically make a case on the basis of the best science
available that theres a problem, and effect solutions that
really change the behavior of people that are very comfortable and
living in those environments and making their livings from the sea.
Its very understandable that people would be upset and question
the validity of the basis for doing these things.
What we have
to do is to put those into perspective, because when we go to the
fishermen, we go to the public and we get their input, what we arent
seeing, in many cases, is all the fishermen who have left the business
because of poor catches, et cetera. And we dont get a perspective
on how big some of these industries could be if theyre regulated
in a proper way and theyre generating the benefits that theyre
capable of generating. These are understandable reactions by people
that feel like theyre being scape-goated in terms of being
responsible for fishery declines.
What we need
to do is to act as a broader society, to try to understand the fishermens
role in this larger issue to use their expertise in helping us design
monitoring programs, and in some cases supporting them, as were
trying to rebuild stocks and trying to get them to reduce their
efforts so we can build these stocks up to sustainable levels. We
need to take this on in a broader social discourse rather than just
having it science versus fishermen, or science versus politicians.
And I think we have taken a too narrow a view when we set this up
as a series of one-in-one confrontations.
Whats your sense, speaking of just the cod and the haddock
stocks, when we might expect to see them back, and secondly, if
they do come back, how do you think that the fishermen are going
to be able to fish again where its sustainable so that the
whole thing doesnt happen again?
problem is repeating the cycle of boom and bust, and thats
what we have to avoid. Economic pain is not only the fishers,
but you and I as consumers, paying high prices for low abundance
fish. We dont want to repeat that cycle again.
simulations and the basic life history data that we have for so
many of these species indicate that recovery times can range anywhere
from five to fifteen years for the typical ground fish species,
like cod and haddock and flounders, et cetera. These are all predicated
on having harvest rates down to10 or 20% per year. If we can achieve
those rates we can get these stocks back to where they should be
in their biomass; we can broaden their age structure to what it
needs to be; and we can start to generate, on an annual basis, more
and more even production of baby fish, recruitment to the fisheries.
But its all predicated on getting those exploitation rates
Now in the northeast,
we have really gone through a kind of a catharsis in fishery management.
It wasnt until the end of 1994 that the fishery management
actually started to bite in a serious way. And this was basically
due to large-scale closures of very large areas in places like Georges
Bank about 6000 nautical miles were closed. And the amount
of effort that each individual offshore fishing boat could generate
was slashed by 50% in terms of their number of days at sea. This
has worked partially, for some of the offshore species and were
seeing some hints of recovery.
On the other
hand, its kind of frustrating because so many of the other
species have not shown any recovery; in fact exploitation rates
remain high. And we have to learn from this comparison, even in
our own region, what works and what doesnt. Its very
obvious that broad regulations work in some cases and they dont
work in others, and it has to do with whos fishing, what methods
theyre using, where theyre fishing, et cetera. And we
need to fine-tune this whole process so that not only certain important
species are brought back, but that the entire ecosystem is brought
back to a productive and sustainable level.
What would a sustainable fishery look like in our region if the
stocks were to have recovered?
fisheries are going to look a lot more different than what theyve
looked like in the last 30 years. With the lack of regulations on
a lot of the industries weve seen basically a free-for-all,
where any kinds of gear can be used, a lot of competition between
gears for by-catch, and not be worried about what theyre throwing
over, et cetera, which happen to be the target of some other fishery.
With sustainable fisheries were going to have to be more cognizant
of cleaning up our by-catch, to make sure that we dont kill
off the young thats supporting another industry. So I think
what well see is a lot more of the spatial segregation of
the fisheries where certain groups are allocated different grounds
to fish, for example.
a lot more gear development perhaps we dont need the
biggest and widest nets and the heaviest dredges, et cetera, particularly
if stocks are abundant. Because a lot of these gears were developed
to catch the last fish, and when theyre abundant you dont
have to be as efficient to make a days pay. And so I think
well see down-sizing of the gear, itll be a lot less
dirty in terms of by-catches, and well see a lot more separation
of the various fleets on the grounds.
You can read
it in the back of National Fishermen. I mean, there are advertisements
for high-quality GPS, that say the fish cant hide anymore
(our environmental friends have told us this). Even if you look
at a scallop dredge theyre wide, theyre heavy,
and theyre built to be extremely quick, so that they can cover
a lot of ground searching for low density. When theyre at
high densities and we just found this out by letting fishermen
into closed areas out there they can make a trip in three
days with five men. They were taking up to 17 men on a sea scalloper
in order to make a trip and be fishing for 14 days. When they are
abundant, theyre easy to catch.
We are never
going to see a return to huge employment on the harvesting sector,
unless we are willing to basically tie one arm behind their back
technology wise. Because technology is a substitute for labor. This
is not the only industry in the United States that that happens
in. We are never going to get back to the labor that we used in
the low technology days. The job growth in the fishing industry
is going to be on the shore sidenot the harvesting side.