Proceedings of the Standing Senate Committee on
Issue 4 - Evidence - March 26
OTTAWA, Thursday, March 26, 1998
The Standing Senate Committee on Fisheries met this day at 9:05 a.m. to consider
the questions of privatization and quota licensing in Canada's fisheries.
Senator Gerald J. Comeau (Chairman) in the Chair.
The Chairman: Honourable senators, our witness this morning is Mr. K. F.
Drinkwater, from the Bedford Institute of Oceanography. Mr. Drinkwater will
speak to us, and also give us a video presentation, about the sciences, an area
that we have not touched on specifically for quite a while.
Mr. Ken F. Drinkwater, Bedford Institute of Oceanography, Fisheries and Oceans
Canada: My presentation is on the impacts of climate variability on Atlantic
Canadian fish and shellfish stocks. After a very brief introduction, I will
give a few examples of environmental effects on fisheries. I understand that
one of the reasons I was invited in the first place was that an article on Gulf
Stream eddies appeared in The Mail-Star and the Chronicle-Herald in Halifax. So
I will talk a bit about the effects of these eddies on recruitment, which is
the number of young fish coming into the fishery.
I also wanted to talk about the effects of temperature on growth, which is
important given the problems we have had in the groundfish industry, and also
discuss the effects of temperature on distribution. We have seen some major
distributional changes recently. I will give a few examples of those. If there
is time, I will discuss the role of the environment in the recent increase in
lobster catches and give my view concerning the role of the environment in the
collapse of northern cod.
I am a physical oceanographer. My approach is from the climate end. That is my
expertise. However, I have throughout my professional career been involved with
environmental effects on fisheries, although I am not a fisheries biologist.
When we talk about fish stocks and stock biomass, we mean the total weight of
the catchable fish that are available, as opposed to numbers of fish. The
biomass can increase through two main processes: either growth -- in other
words, the fish are growing -- or recruitment, which is our term for new fish,
usually young fish, coming into the stock. We lose biomass through mortality,
and the major mortality in the commercial stocks is through fishing. There is
also a natural mortality through predation.
The ocean environment affects these three processes: growth, recruitment and, to
a lesser extent, adult mortality. I will give some examples of environmental
effects on growth and recruitment. The ocean environment also influences the
distribution of fish. The fish may move from one place to another. Environment
can affect the migration routes of fish. It also affects the ability of the
fishermen to catch the fish. It might concentrate the fish or allow them to
spread out; so it affects the ability of the fishermen to catch the fish.
One example of the effects on recruitment appeared in the newspaper article I
have referred to. Let me show you a schematic of the surface currents in the
Northwest Atlantic. This shows the mean currents averaged over a long period of
time. Basically along the Continental Shelf, they move from north to south.
Offshore the dominant feature is the Gulf Stream. Most of you have probably
heard of the Gulf Stream. It is a deep current that carries warm water up from
the south into our region. It actually splits here near the Tail of the Bank,
part moving south, part moving north. That northern branch eventually gets over
to Europe and is one of the reasons they are warm at relatively high latitudes.
The Gulf Stream meanders. It does not have a fixed location. It is like a stream
or a river. Rivers meander quite a bit; if you were able to watch a river over
geological time, you would see it meandering over time. There is nothing to
hold the Gulf Stream in one location, so it tends to move. We call these
What happens when it meanders? Sometimes these meanders will loop on themselves
and actually break off. We have a diagram here of the Gulf Stream. The scale is
down below. This is about 300 kilometres or so, so these meanders are quite
big. North of the Gulf Stream is what we call slope water. That is the water
between the Shelf and the Gulf Stream. To the south of the Gulf Stream is
Sargasso Sea water. The water to the north is colder. The Sargasso Sea is a
little cooler than the Gulf Stream but is still relatively warm.
These meanders will sometimes form quite tight loops and eventually will break
off and move away from the Gulf Stream. These are called Gulf Stream eddies or
rings. If they move to the north, they are called warm-core rings because they
are warmer than the surrounding slope waters. If the loop is to the south, it
traps cold slope water in the middle. Those are called cold-core rings, and they
move to the south of the Gulf Stream.
We can see these in satelliteinfrared images. They show false colours, the
colours representing different temperatures. This shows the area of Florida
right up through Nova Scotia, and the reds down here are 20 plus degrees. We
can see the track of the Gulf Stream as it comes up the coast. As it comes up
you can see a meander here, which is moving off in this direction. We can see
these rings. We see a warm-core ring formed here. It has not quite broken free
of the Gulf Stream, but probably will. There is also a cold-core ring that has
moved to the south of the Stream.
Another satellite imagery of temperature in June shows the Gulf Stream and a
very distinct warm-core eddy off the Shelf just south of Cape Cod. It is very
distinct in the satellite imagery. For this same date, we also have colour
imagery which depends on the amount of chlorophyll that is in the water. The
blue means there is less chlorophyll in the water, less production. The red here
means that there is very high chlorophyll. So there is a lot of chlorophyll in
the coastal regions and we can also see basically the outline of Georges Bank
where there is a lot of productivity. You can see the ring as a circle of
chlorophyll. This is because there is less productivity in the Sargasso Sea-Gulf
Stream waters than in the slope water and Shelf waters. The point of showing
this picture is to indicate that the associated flora and fauna move with these
What happens when these rings move up against the Continental Shelf? The Gulf
Stream is about a thousand metres or more deep. These rings are about the same
depth. The Continental Shelf is about 200 metres deep. The rings are like a
spinning top. The top of the eddy cannot separate from the bottom. Dynamically
they are locked together. So when the ring comes up against the Continental
Shelf, it bumps up against it but it cannot move onto the Shelf.
So it is sitting there spinning, and because it is spinning it will in turn
entrain water, or pull water off the Shelf out into the slope water region.
The next diagram shows some work done by one of my colleagues, Ron Trites, back
in the early 1980s. In this picture, you can see Nova Scotia, the coast of
Maine and the edge of the Shelf. The blue line here represents the extension of
the Shelf waters and the red represents the Gulf Stream. It shows schematics of
the surface temperature off Nova Scotia based on those thermal imagery shots
that I showed you before. There are three distinct eddies.
Shelf water is being pulled off by one of the eddies. The Shelf water is
wrapping around the eddies and is being pulled off the Shelf out into the slope
water region. What was nice about this study was that they had drifting buoys
out there at the same time. Their positions were tracked by satellite, and over
time they were able to show what tracks they had. I have showed those in green.
The track of one of the buoys is moving around the eddy. Thus, it is moving in
the direction that we would have expected based on the thermal image alone. We
have another buoy that is being pulled out into the slope water by the Gulf
So these eddies have an important effect on the Shelf, in that they will move
Shelf water offshore. If Shelf water moves offshore, something must replace it.
Sometimes some of the slope water gets pushed onto the Shelf. Sometimes some of
the water from the eddies themselves will break off and move in. The flora and
fauna that is associated with these waters will also move onto the Shelf.
Oftentimes in Nova Scotia there will be reports of findings of species that are
not native to Nova Scotia -- things like sea horses. That is the process by
which many of those species enter into our waters.
Similarly, the cold-core eddies that we are seeing in some of the satellite
images will move arctic-type species from our northern waters much further
south than they normally appear. Eventually they die.
Getting back to the Shelf, because Shelf water is being moved off, it was
suggested in the 1980s that if there are eggs and larvae in that water, they
will be moved out into the slope waters away from the Shelf and might be lost
to the population. Therefore, the recruitment or the number of young ones that
will make it into the fishery should be reduced.
Mr. Ram Myers, a colleague of mine who is now at Dalhousie, and I did a study 10
years ago. We explored the hypothesis that the presence of these Gulf Stream
rings would indeed reduce the recruitment of the groundfish stocks. We looked
at the number of rings that were present during the period of time that we
expected to see eggs and larvae in the water, and we also looked at the distance
the rings were offshore, because the closer the rings are to the Shelf, the
more Shelf water we would expect to be entrained off. We generated a
stock-specific ring index based on these two items.
We found a negative correlation between the ring index and 14 of 17 groundfish
stocks that we looked at.
The Chairman: What is a negative correlation?
Mr. Drinkwater: A negative correlation means that if there are more rings in the
area when the fish are spawning and the rings are closer to the Shelf, we have
reduced recruitment. Here is an example. We looked at 17 stocks. The species
were cod, haddock, pollock, redfish and yellowtail flounder. They ranged from
the Tail of the Grand Banks to Georges Bank. Actually, when we went into this
analysis, both Ram and I felt that there would be no relationship.
The correlations were not high for many of the stocks but 14 of them were
negative. If there was no relationship between the rings and the recruitment,
one would expect to see half of them negative and half of them positive, just
by chance. The fact that most of the relationships were negative told us that,
yes, there is an effect. It is not a strong effect, but, yes, there is an
Indeed, when we looked at it in more detail, we found that if you had lots of
ring activity when the eggs and larvae were in the water, you never had large
recruitment for that particular year-class. On the other hand, you could get
low recruitment whether there were lots of rings or not. So that meant that
there were other processes besides this one affecting and controlling
recruitment. Rings had an effect, but it was not a dominant effect.
Senator Stewart: What is your explanation of the three exceptions over on the
right side, the "Y", "C" and "C" -- that is the
Mr. Drinkwater: Our feeling is that recruitment is not dominated by this
process, and so one expects that there are other processes that control
Senator Stewart: Let us take cod. We have cod stocks that show strong negative
correlations and other cod stocks that show positive correlations. Do I
understand correctly that those are in different areas?
Mr. Drinkwater: Yes. This one here is on Georges Bank, and this one is on Browns
Bank. The strongest negative correlation is on St. Pierre Bank. So for the
stocks in the north, there seems to be a stronger negative relationship than
there is to the south.
Senator Stewart: The negative relationship is greater as you go north?
Mr. Drinkwater: For the cod species, that does appear to be the case. There had
been little evidence or observation of the eggs and larvae of the Shelf species
entraining into the offshore waters. Back in 1991, we were on Western Bank
studying cod. It was understood at that time that there was spring and fall
spawning on Western Bank -- down in this area. We went out in the spring and
looked for cod larvae but could not find any. There was lots of ring activity
at that time. That was April of 1991. We thought one of the reasons there was
no cod larvae out there was that they had been entrained into the offshore
waters by the rings; so we went offshore and sampled in the area near Sable
Island. We did not find any cod larvae, but we did find redfish larvae. Now
redfish spawn along the Shelf edge in the spring and then, as the summer
progresses, they spawn more inshore. We were wondering what sort of condition
these larvae were in compared to the larvae on the Shelf.
The next diagram shows the amount of redfish larvae as a function of depth and
temperature. We see that most of the redfish larvae are up in this area of the
graph, which means in the top 30 or 40 metres in temperatures of 2 to 5 degrees
C. That is Shelf water. So we were finding redfish offshore but in Shelf
waters. We were not finding any in the warmer slope waters.
We wanted to see if the larvae were in good condition off the Shelf. One of the
measures of condition is the amount of weight for the size; if they are bigger,
they are in better condition. We took the mean relationship between the weight
and the length for all of the area, sampling offshore and on the Shelf as well.
We wanted to see whether the ones off the Shelf were in better condition or
worse condition than the overall mean.
Offshore there were more larvae that weighed less than the mean, whereas on
Western Bank, on the Shelf, most of the larvae weighed more than the mean. That
says that the larvae on the Shelf are in better condition than the ones off.
That suggests that the ones that are moved offshore are probably not getting as
much food. Certainly, the longer they stay offshore, the poorer condition they
will be in and the more likelihood that they will die. In other words, one way
in which the larvae can be removed and the recruitment lowered is through less
Another way is through thermal shock. For instance, at this time of the year,
the Shelf water is 4 degrees Centigrade, and offshore it is 8 to 10 degrees.
That is a 4- to 6-degree temperature change over a few kilometres, and that is
very sharp. If the larvae are used to 4 degrees and all of a sudden they are
put into temperatures that are twice as much, they will be in trouble.
This overhead shows the ring activity and the entrainment features over April 22
to May 8, the period in which we were sampling. Most of our sampling was just
south of Sable Island. At times, especially by May 1, some of this water is
being entrained even further offshore.
If we look at the entrainment features, they vary quite a bit over relatively
short periods, and certainly by May 8 one of the entrainment features totally
disappeared. Thus, within a very short period of time shelf water is moved out
into slope water and mixed in. Those larvae would go from 4 to 8 degrees
Centigrade over a couple of weeks or probably much less. That can result in
thermal shock and they can be killed that way.
In fact there was a paper published in the early 1950s that showed cod dying
from this process near Georges Bank.
In summary, there is evidence that increased warm-core ring activity causes
reduced recruitment in several groundfish species, and this is believed to be
due to increased transport offshore, where they die either from thermal shock,
reduced food or the inability to get back to the Shelf when they metamorphose,
that is, when they are ready to drop to the ocean floor. If they want to drop to
the bottom when they are in water that is over 4,000 metres deep, they will not
make it. They must be on the Shelf. Those offshore cannot swim back to the
Shelf to metamorphose there.
Senator Stewart: What does "metamorphose" mean?
Mr. Drinkwater: That is when the cod are ready to leave the larval stage and go
into the juvenile stage. In the larval stage, they are up near the surface of
the ocean. They are up in the top 30 metres or so, and when they metamorphose
they go down to the bottom.
High recruitment never occurs in years of high ring activity, but you can get
low recruitment regardless of whether you have lots of rings or a few rings.
This suggests other processes also affect recruitment. Finally, field studies
have provided evidence of entrainment of the redfish larvae offshore. They were
found to be in poorer condition, and that supports the hypothesis that Ram and I
had investigated in the first paper.
Senator Stewart: You say that they drop to the bottom. The implication is that
the larva is near the surface and, when the metamorphosis takes place, the
entity goes into deeper water; is that correct?
Mr. Drinkwater: Yes. All the ones that we looked at were groundfish species, so
they spend their time on the bottom once they complete their larval stage.
Senator Jessiman: You are saying the more ring activity, the fewer fish?
Mr. Drinkwater: The less young ones will potentially make it through into the
Senator Jessiman: Looked at over the years, do you know whether there is more
ring activity now than there was before? If there is more now, why?
Mr. Drinkwater: We have not actually done that. The study that Ram and I did was
10 years ago. We are now in the process of updating it. We have not completed
that study yet.
Senator Jessiman: Are you trying to find out whether the activity is the same as
10 years ago or more or less and why?
Mr. Drinkwater: Yes. We do know that the Gulf Stream moves. We have seen
low-frequency or long-term shifts in the position of the Gulf Stream. At the
beginning of the 1980s, for example, it was further offshore. Through the 1980s
and into the 1990s it has been closer inshore. According to the most recent
data it is starting to move back again. Maybe these movements are coupled to the
amount of ring activity. We are looking into these, but we have not explored it
in detail. What we must do is accumulate the 10 more years of data available
since our earlier study. We will get the recruitment data for each of the
species, each of the stocks that we investigated, generate our stock-specific
ring index and redo the analysis and determine if our previous results hold up.
I do not feel that this process led to the collapse of the cod on the Scotian
Shelf, for example. It might have , but I do not think rings were the major
factor. If you have a relationship between recruitment and rings, but it is not
the dominant process controlling recruitment, and if somefactor is dominant,
then it is often difficult to prove relationships between recruitment and
non-dominant mechanisms such as ring activity.
I want to talk a bit about the effects of environment on growth, in particular
temperature. This figure was from a study done by Keith Brander. He looked at
all the cod stocks around the North Atlantic. In the top diagram, the bars
represent the catches of cod for different stocks. Most of the cod catches are
from the northeast part of the Atlantic. The biggest stock we had was the
northern cod. Obviously, these data were collected prior to the moratorium.
Keith Brander looked at weight of a four year old cod as a function of bottom
temperature. Size is plotted on a natural log scale so that a value of one
represents over a twofold increase in size. We can see that the biggest cod are
in the Northeast Atlantic. Many of the Canadian stocks are at the low end, that
is, they are the smallest cod that one sees. We have a few stocks here in the
middle of the size range, that is, the ones on Browns Bank and Georges Bank.
The next figure shows it more visually, indicating the relative size of a four
year old cod on Georges Bank through to Sydney Bight. The size of the same age
cod varies by about a factor of two. The larger cod occur where it is warmest.
Temperature can explain the differences between growth rates of cod for
different stocks, but it also can explain some of the year-to-year variability
in growth of an individual stock. For example, the stock in the northeastern
part of the Scotian Shelf, which was looked at by Steve Campana and his
colleagues; they showed that temperature was able to account for 50 per cent of
the year-to-year changes in the growth of an eight-year old cod.
Since the mid-1980s, there has been a decrease in growth rates of cod on the
Scotian Shelf. At the same time, there has been very cold water that has moved
onto the area. It is not only in cod that we see the dramatic changes in size.
We also see it in haddock. Beginning around 1985, the older haddock decreased
from a mean length of about 65 centimetres to about 45 centimetres for the same
age cod over about a 10-year period. That is a dramatic change.
We usually talk about stock biomass, as I said in the introduction. When size is
smaller, if you have the same number of fish, you can have dramatically less
biomass because of the changes in the growth rates.
Temperature-dependent growth occurs not only on the Scotian Shelf, but also off
Newfoundland. Some studies there looked not at temperature per se but at what
we call the cold intermediate layer. In the winter the waters are very cold on
the Shelf. They drop below minus 1 degree Centigrade. In the summer the waters
near the surface warm up. Temperatures below this layer remain very cold.
Waters near the bottom are warmer because they come in from offshore. Thus the
waters at intermediate depths are colder than the water above or below it. That
is why we call it the cold intermediate layer.
The amount of cold intermediate layer water as measured by temperatures less
than zero degrees varies from year to year. For example, off Bonavista Bay off
northeast Newfoundland, there was a lot more cold water in 1991 than there was
The next diagram will show the comparison between the area of this cold
intermediate layer and cod growth in 2J which is southern Labrador, 3K and 3L.
We can see a strong decline in the growth increment of 2J cod of about 50 per
cent from the mid- to late 1970s through to the late 1980s. The area of the
cold intermediate layer can account for 50 per cent of the changes in the
growth rate of the northern cod over this time period. Definitely temperature
has an effect on growth rates.
I want to show some of the information on distribution. Capelin is a cold water
fish and the major source of food for cod, certainly for northern cod. The
major stock is off northern Newfoundland; there are also stocks in the northern
Gulf of St. Lawrence and at the southeastern Grand Banks near the tip.
In the mid-1980s, when cold water moved onto the northeastern part of the
Scotian Shelf, causing a decrease of about 1 degree, we started to find capelin
on the northeastern part of the Scotian Shelf.
If we were to plot the number of capelin that were there in the late 1970s and
early 1980s, there would be none on the Scotian Shelf. The next plot shows a
dramatic increase in capelin catches in the spring and summer surveys.There is
about a hundredfold difference between the low catchers in the 1970s and the
high catches in the 1990s. They increased in huge numbers when the temperatures
dropped. Temperatures have remained cold and the capelin have remained on the
northeastern part of the Scotian Shelf.
It is interesting that there was one earlier period when temperatures became a
bit colder and indeed capelin appeared. Definitely there has been a change in
the distribution of capelin on the Scotian Shelf.
Here is another example of distributional changes off Newfoundland. An index of
temperature from a station near St. John's has been shown to be representative
of the whole Shelf area. In the 1960s, temperatures were quite warm. They
decreased through to the early 1990s. They have since recovered a bit, but
certainly had experienced a major decline.
During that decrease in temperature, several species changed their distribution.
One in particular, which was quite dramatic is Arctic cod, which is smaller
than the Atlantic cod and certainly not as commercially important. Its major
concentrations in the 1970s were in northern Labrador, and there were a few on
the Grand Banks, but not very many. That was in the late 1970s. By the late
1980s, there were still large numbers around northern Labrador, but they pushed
their way southwards. As the water got colder, we saw more and more of them
further south. In the coldest period in the early 1990s, we had their furthest
extension southward. They are now firmly entrenched on the northern part of the
Grand Banks. They have also worked their way into the northern Gulf of St.
Lawrence. That is certainly a dramatic shift in the distribution of Arctic cod.
That finishes the examples of the general effects of environment on fish. I will
now talk to you about lobster and then northern cod. This is a plot of the
Atlantic Canadian lobster landings. We can see that when the fishery opened,
which was in the latter part of the 1800s, catches were very high. They
declined in the early 1900s. This was believed to be the result of removing the
excess, the larger lobsters. The fishery then arrived at what people considered
a period of sustainable yields, somewhere around 20,000 metric tonnes.
However, in the 1980s catches increased dramatically, and they increased through
the late 1980s into the early 1990s. Since then they have been slowly
The landings for various locations from Newfoundland through to Rhode Island
show that almost every area from Newfoundland to Rhode Island exhibited this
tremendous increase in lobster catches. They were at all time historic levels
in most areas. One exception is Guysborough and the surrounding counties along
the Atlantic coast of Nova Scotia, where catches did increase, but they were
nowhere near historic levels.
Senator Stewart: When I was in the House of Commons, I represented Guysborough
County as well as Antigonish. I was told back in the early 1960s that the
lobster fishery along the eastern part of the Guysborough shore, let us say
Chedabucto Bay just east of the Canso causeway, had been quite high, but then
there was a drop. Now, the local wisdom on the wharf was that the drop,
particularly in the Chedabucto Bay area, related to the construction of the
Canso causeway. Formerly, the larvae would drift through the warmer waters of
the Gulf into the cold waters of the Atlantic, but once that causeway was
constructed the natural migration of the larvae was terminated so that lobster
virtually disappeared in Chedabucto Bay. There was a drop in the lobster catch
in Guysborough County, but the causeway was opened in about 1955. Could an
imaginative person detect any relationship between the wharf wisdom on the one
hand and your graph on the other?
Mr. Drinkwater: Yes, they could. Indeed, I and a colleague have looked at that.
There was a workshop on that very issue held in St. Andrew's back in the early
1980s or late 1970s. There was a lot of debate. Scientists argued both sides,
some that there was an effect and others that there was not.
Since then we have made an estimate of the concentration of lobster larvae in
St. George's Bay north of the causeway and estimates of the flow rates being
transported to Chedabucto Bay from St. Georges Bay, and there was a mean flow
from the Gulf to the Atlantic side because of the slight differences in sea
level. We then estimated how many larvae would actually make it in and did some
modelling as to how many would be lost through mortality. We came to the
conclusion that there was an effect that would have contributed to a decline. A
paper was published with those results. I can send it to you if you like.
Senator Stewart: It is nice to know that the wharf wisdom was correct.
The Chairman: If you would, please send it to the committee and we will make
sure copies are distributed. It should be on the committee's records.
Senator Meighen: On the question of landings, and my recollection is from
reading newspapers, is it true that there was a deep water lobster fishery that
developed in the 1960s or 1970s right out on the Shelf rather than in the
inshore fishery? Would that not have accounted to some extent for increased
Mr. Drinkwater: Yes, but not a great deal. There was an increase in offshore
catches. Certainly, in Canada the amount of offshore licences have been limited
because of questions over whether the offshore lobsters are seeding the inshore
lobster population.. There is a fishery offshore on Georges Bank and, indeed,
the expansion of the fishing to grounds that were not traditionally fished has
gone on, and that will account for some of the increase. We do not feel it is
the full story, however.
Senator Stewart: Before you go on, we have talked about the Guysborough County
exception. Will you repeat how you are explaining the increases in the other
Mr. Drinkwater: I am getting to that. When scientists first saw this widespread
increase from Newfoundland all the way down to the mid-Atlantic Bight, they
knew it was obviously not regulation that was doing it, because the regulations
differ. They felt initially that it probably was an environmental effect. They
said possibly temperature changes, because there had been past studies in at
least three different areas that all came to the same conclusion: when
temperatures rise, you tend to find higher lobster catches.
We decided to look at this. We took the past relationships and extended them to
see if we could forecast this big increase. If we could, then it would be an
argument that temperature was the cause.
We did it for the three different areas, the Gulf of Maine, the coast of Nova
Scotia and the Magdalen Shallows. I will show you the results from the Magdalen
Shallows. The results from all three areas showed exactly the same.We predicted
the lobster catchers based on temperature from an early study that looked at
data from the 1940s through to the early 1970s. Then we used recent temperatures
to predict lobster catches in the 1980 and 1990s. Temperature alone could not
predict the increase in the lobster landings.
The lobster landings represent such a high percentage of the adult lobster that
they are not a bad measure of the recruitment, the number of young ones that
are coming into the fishery.
Temperature also did not increase uniformly over this area over from
Newfoundland to the Mid-Atlantic Bight. We concluded that the recent increase
in lobster landings was not due to a temperature effect, although in the past
there had been a relationship landings and temperature. One of the problems in
doing this kind of research is that the factors controlling recruitment do not
Let me try to summarize. This large increase in lobster landings was widespread,
and was not due to temperature. Now there has been an increase in fishing
effort, including what was mentioned before about the expansion to other
grounds. They are also using wire traps, which are more efficient than the old
wooden traps, but we do not feel that changes in effort can account for the
entire increase in landings.
There have been estimates from groundfish trawl surveys and from the fishermen
themselves that there were a lot of younger lobsters during this period when
the lobster catches were increasing. Our opinion is that there was a
recruitment pulse, lots of young lobsters out there. For what reason, we still
do not know.
One thing which has been suggested is a decreased predation because of the loss
of the groundfish. Scientists are looking at that. It is certainly not
predation by cod. Work done in Moncton looked at 15,000 cod stomachs but did
not find any evidence of lobster in any of them. One species in which they did
find lobster was sculpin. We do not have any estimates on sculpin abundance,
whether it has gone up or down, because it is a non-commercial species.
Senator Stewart: You talked about the capelin moving down off the Cape Breton
shore, and that was related to cold water.
Mr. Drinkwater: That is right.
Senator Stewart: Now you are talking about the water warming in the case of the
Mr. Drinkwater: Lobsters like warm waters, or in the past they liked warm
waters. There was a relationship between the temperature increases and
increases in the landings. It was not stated that the water was warming.
Senator Stewart: Was the water, for example, around the Magdalen Islands getting
colder in the same period that the capelin were going down off St. Pierre and
Miquelon because the water there was getting colder?
Mr. Drinkwater: Yes, it was in fact. It was colder around Newfoundland,
certainly on the Magdalen Shallows and the northeastern Scotian Shelf. It was
not in the Gulf of Maine. The Gulf of Maine was increasing, actually.
Senator Stewart: Yet you say the lobster catch went up in that period.
Mr. Drinkwater: Exactly. Temperature cannot account for the increases in their
I will now talk a little bit about northern cod landings. This is my view of
things, not necessarily the view of the department or perhaps even of many of
This figure shows the catches of northern cod, and 2J again is southern
Labrador, 3K and 3L stretche from northern Labrador to the Grand Banks.
Senator Jessiman: I cannot read the bottom line.
Mr. Drinkwater: Those are the years. The plot starts in 1850 and goes through to
1995. It is essentially zerosince 1995. For over 100 years there was a gradual,
very slow, steady increase primarily in the inshore fishery. Then in about 1960
we had this huge increase in catches. This is when trawling began. We had the
foreign fleets coming in, the distant water fleets from Russia, Cuba and
Senator Jessiman: Does this indicate what you are taking out or what is there?
Mr. Drinkwater: That is what is being taken out. These are landings, catches.
They remained high, up over 800,000 metric tonnes in the early 1970s. There was
a decline as we declared the 200-mile limit. Catches rose a little bit. We
thought we were heading up, and then of course we came crashing down. There has
been a moratorium since the early 1990s.
Now, it has been shown and published that overfishing is probably the major
cause of the collapse of the northern cod. What role did environment play? Did
it play any? I believe it has.
In the 1960s the huge increase in catch was due to trawling. The trawling was
removing the older, bigger fish. What that does, we found out since, is to
remove the reproductive potential. The older, bigger fish produce more and
better eggs than the younger ones. So by removing all those older fish, we have
lost reproductive potential.
Second, the cold temperatures that we saw through the 1980s and into the early
1990s resulted in decreased growth rates, so the fish were not in as good
condition. In order to maintain your quota with smaller fish, you must catch
more of them because the quotas are in terms of tonnage, biomass. We certainly
saw a decrease in spawning-stock biomass, and at least 50 per cent of that, I
believe, or around that figure, was due to the loss in weight, not in terms of
removal of numbers.
We have seen before that temperature accounts for about 50 per cent of the
reduction in the growth rates. So certainly temperature played a role in
decreasing the amount of biomass that was out there.
Senator Jessiman: Is that the temperature going up or down, because you said the
colder it was, the smaller the fish?
Mr. Drinkwater: There are two things here. There is the differences between
geographic locations and there are differences in stocks.
Senator Jessiman: You said colder water up north produced smaller fish.
Mr. Drinkwater: Right. Then in southern Labrador and northern Newfoundland you
have temperature changes, so when it is even colder, the fish get even smaller.
Senator Jessiman: It is the water getting colder?
Mr. Drinkwater: That is right. Now, one of the other things that the smaller
sizes meant was that you had more high-grading. High-grading is the process of
discarding the smaller fish. Fishermen have admitted that discarding, or
high-grading, did go on. Certainly, this had an effect on the smaller fish,
which again temperature played a role in.
Fourth, we know that there was recruitment failure so that there were few new
fish coming in. Certainly, as the spawning stock biomass went down, there were
fewer adults to spawn. There was this loss of reproductive potential due to
fishing during the 1960s and early 1970s. There was also cold conditions which
generally are not conducive to big recruitment years.
The cod in the northern areas are not only smaller, but they also mature later.
Whereas cod on Georges Bank might start to be mature at age 2 or 3, up in
Newfoundland the cod are 6 or 7 years old before they really start to
reproduce. They have been hit hard from fishing, but it also takes them a heck
of a long time to start to reproduce. So it will take them a long time to
recover from relatively low abundance levels. Again, that is in part because of
the cold waters that they inhabit.
Cod distributions tended to move further south, with the biggest declines in the
cod abundance in 2J off southern Labrador. Earlier I showed some pictures of
Arctic cod moving south. Whether this movement in the Atlantic cod is due to
environment, we are not quite sure. It might also be due to the fact that they
have low abundance and maybe they are moving because of that. It may be due to
increased predation by seals, which has been mentioned many times.
Temperature has played a role in the decline of the northern cod; however, it
has been pointed out in the literature that the temperatures and conditions
that we saw in Newfoundland in the late 1980s and early 1990s were not any
worse than what we saw in the late 1800s. That was a period of very cold
temperatures, but the cod did not collapse then. Why not?
Back in the late 1800s it was as cold as it has been in recent times. However,
we took out this reproductive potential by removing the large fish and there
have been trawlers fishing on the spawning grounds. In the late 1800s they were
not fished very much in those areas. There use to be a tremendous amount of cod
offshore, which acted like a buffer for the inshore fishery. If you had a few
years of bad recruitment, there was still enough fish offshore that could move
inshore and still keep your catches high, hence there would be no collapse.
With these big catches in the 1960s and early 1970s, many of the older fish were
removed, again affecting the reproduction potential. In this period from the
early 1970s through to the early 1980s, we hit that spawning stock hard. We
basically lost our buffer, so if we had a few years of bad recruitment we would
be in real trouble, which did in fact happen. So that is my view of what
happened with northern cod and the role that environment has played.
The Chairman: Could you send copies of these last two or three sheets to us?
This is the best explanation I have heard to date.
Mr. Drinkwater: We have made arrangements to get all the slides copied.
Finally, the climate and ocean environment does play a role on fish and
shellfish stocks. It influences growth, reproduction, distribution, recruitment
and a few other processes I have not listed. It is species dependent. Not all
species react the same. If the water becomes cold, different species may react
differently. Also the same species can react differently. For example, Atlantic
cod on Georges Bank can react differently to northern cod, or off Newfoundland.
There is research being conducted on the linkages between environmental change
and fish stocks. It is often difficult, however, to predict specific responses
to environmental change because of the effects of fishing. Species interactions
are a factor as well. One species could replace another; that may not be due to
environmental change. There was a case of the herring in the Gulf of St.
Lawrence when disease wiped them out and the mackerel came in. Also, there is a
lack of good recruitment time series for many of the stocks.
Senator Stewart: You talked about water getting colder, yet we are being told
that the climate is moderating. Certainly where I live we do not get the deep
winter ice in St. George's Bay now that we got when I was 15. There has been a
dramatic change. I would say the waters are warmer, but obviously I am wrong,
or at least the water I am talking about is not the same water you are talking
about. Will you explain?
Mr. Drinkwater: I want to go first to the Labrador area and show Plots of winter
air temperature, winds, ice, sea ice area and temperature off St. John's. The
results show that the air temperatures have decreased from the 1960s. The 1960s
was a warm period in the Labrador Sea. The temperature has been decreasing
since then with variability over about a 10-year period, according to these
Thus there is a decline, plus this 10-year oscillation on top of it. This is
related to the large-scale atmospheric pressure patterns, in particular the
strength of the Icelandic low, a low pressure system over Iceland in the
winter. When that strengthens, it brings stronger northwest winds over the
Labrador Sea. They bring cold air down. More ice forms. The ocean cools. That
has been going on since the 1960s with this 10-year oscillation on top of it.
It flies in the face of global warming, but in this particular area
temperatures have cooled.
Now some of the recent models have suggested that there should be cooling
initially in this area. The models have not predicted the strength of the
cooling that we have seen over this 30-year period. For whatever reason, this
area has been cooling.
In the mid-1980s, very cold water was found in the Grand Banks area. The changes
were dramatic in the St. Pierre Bank area, throughout the Gulf of St. Lawrence,
in particular the Magdalen Shallows and in the northeastern part of the Scotian
Shelf. We are not sure of the cause and are researching it now. It might be
advection of cold water that moved south from Labrador. There is also the
possibility of winter cooling in the Gulf of St. Lawrence and locally.
The Scotian Shelf is complex topographically. There are deep basins in the
middle of the shelf and in the Gulf of Maine. These deep basins have been very
warm, so there are differences geographically in terms of what waters are warm
and what are cold. It varies from location to location. It also varies in what
layer of depth you are looking at. These very cold temperatures are in the
intermediate depths to the bottom, but when you come to the centre part of the
Scotian Shelf or the Gulf of Maine, the bottom waters are warm and the
intermediate layers are cold, so it is a little bit complex. I am not sure I
have answered your question entirely.
Senator Jessiman: You said you are not a fisheries biologist. What are you?
Mr. Drinkwater: I am a physical oceanographer.
Senator Jessiman: How long have you been with the department?
Mr. Drinkwater: I first came in 1973. I was there for a few years, left for a
year and came back, and I have been there since 1976.
Senator Jessiman: You say that a number of you -- and I assume you are talking
about within the department -- have different ideas as to what should be done
or what we can do about it.
Mr. Drinkwater: That is right.
Senator Jessiman: Are you part of the team that recommends what the government
Mr. Drinkwater: I do not know. They know of our work.
Senator Jessiman: I just read in the papers that the Reform Party is suggesting
that a number of people are making recommendations about who should be fired.
Do you know what they are complaining about?
Mr. Drinkwater: That is at the very upper levels. I am nowhere close to that. It
is at the deputy minister level.
Senator Jessiman: So you are secure.
Mr. Drinkwater: I hope I am.
Senator Jessiman: They must be having the same problem south of us, are they
not, in the United States, in terms of the cod?
Mr. Drinkwater: There have been problems with the groundfish industry. Their
problems might be slightly different. I am not an expert in this field, but
their policy up until recently was to let people fish fairly intensively. So
that got them into problems recently.
In fact, the cod on Georges Bank and Browns Bank do not have some of the
problems that we do in the northeastern part of the Scotian Shelf, Gulf of St.
Lawrence, et cetera. They have been fished heavily too, but the temperatures
are much warmer, therefore the fish mature earlier and can respond quicker to
declines. If they have a bad year or recruitment year, it does not take them as
long to recover, and maybe that is enough to keep them going. That is just one
Also, the seal population is much larger to the north of those areas, and maybe
the seals have a larger part to play than we have been able to demonstrate.
Senator Jessiman: The moratorium has not accomplished what we had hoped it would
in the kind of time we would have liked. Are we seeing some improvement, or do
you know? Ten years from now, will the moratorium bring the cod back?
Mr. Drinkwater: I attended the cod assessment meetings in St. John's at the end
of January. The outlook is not good. There is still no big recovery in the
northern cod in the Gulf of St. Lawrence or the northeastern part of the
Scotian Shelf. The numbers are as low or lower than they were at the
Senator Jessiman: If it is overfishing, have we taken so much out that it can
Mr. Drinkwater: That could be the case. This is not to say that they will not
come back, but it has certainly not been overfishing that has kept them low
over the last little while. We have reduced the spawning stock biomass to very
low levels, and the environment has not been great. So those things coupled
together have perhaps delayed the recovery.
Senator Jessiman: The senator points out that the moratorium just applies to
Canadians, so others are still fishing there, are they not?
Mr. Drinkwater: Others are still fishing in certain areas. For example, on the
northeastern part of the Scotian Shelf or the Gulf of St. Lawrence, that is not
a big issue, so the foreign fishers are certainly not targeting cod. They could
catch cod as by-catch, but at least as far as I know that is not the case.
The fish have been hit very hard. I have tried to make the case that these cod,
in particular in northern Newfoundland, are disadvantaged relative to the rest
of the cod stocks in the north Atlantic. They come from a very cold area. It
takes them a long time to mature and grow. Their numbers were down to low
levels and they have just not responded.
Senator Meighen: Going back to the comparison with our neighbours to the south
in terms of lobster fishing, my understanding is that they do not have a
staggered season. They fish lobster all year round; at least they do in the Bay
of Fundy. We have staggered seasons. Have you been able to draw any conclusion
as to the worth of our system as opposed to theirs?
Mr. Drinkwater: Again, in spite of these differences, we had similar trends in
the abundance of the landings at least. It appears to us from our work that
there was an across-the-board increase in recruitment throughout the entire
area. I really cannot comment on what effects those regulations have had.
However, when we started to see the rise, I certainly felt that we would see a
decline, too. We can slow that decline perhaps by regulations, but I am not
sure that we will be able to change the decline, to level it out, until we
understand what caused the recruitment increase.
We are at all-time historic levels in lobster catches. We cannot maintain those
historic levels. We know that these stocks vary in their abundance. I expected
to see some sort of drop and we are seeing that now. The decline is not that
fast, which is certainly encouraging to the lobster fisherman.
Senator Meighen: Turning to a fish that is not your area of interest, the
Atlantic salmon, the best theory so far to explain the precipitous drop in the
numbers of Atlantic salmon has been temperature changes at sea. Have you had an
opportunity to discuss your findings in terms of water temperature with the
people primarily interested in Atlantic salmon?
Mr. Drinkwater: Yes, I have. There was an Atlantic salmon meeting in Sydney in
February which I attended. Salmon is one of the few stocks where we have used
an environmental index to make predictions for assessment purposes in terms of
the numbers returning. This was work that Dave Redden from Newfoundland and
some colleagues from the U.S. developed. It is a thermal index that measures
the waters whose temperatures fall between 4 and 8 degrees, the ideal
temperatures for salmon. The Atlantic salmon migrate to the Labrador Sea over
winter. When there is a large amount of water there between 4 to 8 degrees in
the Labrador Sea, the salmon seem to do well. The Atlantic Salmon migrate to
the Labrador Sea to winter over. When the area of water in the Labrador Sea at 4
to 8 degrees is large, the salmon seem to do well during the winter. When there
is a small amount, the salmon do not seem to do as well. They have used the
index to make predictions of returns to the rivers.
This past year, lots of smelts were leaving the rivers. The thermal index
indicated that things looked really good, so they predicted reasonable returns,
but they did not get many returns in 1997. They were much lower than predicted.
There was a lot of discussion around the table at Sydney. Unfortunately, I had
to leave before the final day so I am not sure what was resolved.
Senator Meighen: They did not get resolved.
Mr. Drinkwater: I did not think they did. It was very difficult to tell what was
the cause of the low returns. There were lots of suggestions, but no one could
come up with a conclusive reason.
Senator Meighen: In terms of the Bedford Institute, is your funding static, has
it gone down or is it going up?
Mr. Drinkwater: It has gone down dramatically. We lost approximately a third of
our people. I did hear yesterday that there was new money coming in, A-base
monies for the research, so it looks like maybe things will start to increase
Senator Adams: You mentioned seals a few times. Are you concerned about the
seals eating so many cod? I attended the Seals Association in St. John's,
Newfoundland. I do not know if you were there. You have been discussing how
temperature change in the water slows the growth of cod. The seal quota every
year is somewhere around 280,000. I heard that there are now between 5 and 6
million seals out there. Animal rights activists say the seals do not reduce
cod numbers. What is your feeling on that?
Mr. Drinkwater: Certainly again, this is debated heavily both within and outside
the department. There are people on both sides of the fence. On the
northeastern part of the Scotian Shelf, the cod are affected by the dramatic
increase in seals around Sable Island. Assessment scientists have now built
into their assessment models the number of young cod or cod those seals would be
eating based on diet studies that determine the amount of cod found in the
seals' stomachs. They then multiply this number by the number of seals that are
out there. Certainly seals have a substantial effect on the mortality of the
young cod. The researchers are building those numbers into the assessments.
They have less data for Newfoundland. They have not done that as far as I know
for northern cod. Seals definitely have an effect. The problem has been to try
to quantify it and get actual good numbers to put into the models.
Senator Butts: I just want to return very briefly to the cod moratorium. You
stated that temperature has at least some effect on this problem. Cod in cold
water will only be big enough to reproduce at eight years old. There is more
capelin too because the water is colder. So why did the moratorium not work?
Should we now write it off forever?
Mr. Drinkwater: We certainly cannot write it off forever. We keep hoping, but it
has not worked. We have not had good recruitment.
Senator Butts: Have we reached the point of no return?
Mr. Drinkwater: I do not know. Most of the cod people in the department, at
least the ones I have talked to, feel that this is not the case, that the cod
will return, but it will be slow. When we start to see recruitment coming in,
it will still be several years down the road before we can catch them because
we must allow them to reproduce.
Senator Butts: Temperature is more important for some fish, for example silver
hake. Silver hake is one fish for which they are increasing quotas. Will it be
in danger because of the temperature?
Mr. Drinkwater: They do like it fairly warm. One area where they are caught in
fairly high abundance is in Emerald Basin on the Scotian Shelf. Between
December and February we found that there was a large influx of colder water
into Emerald Basin. If that water remains there for a long period of time, it
could have an effect on the silver hake.
Senator Butts: As water temperature has such an effect, is it possible that down
the road we may have variations in the times of the fishing seasons in order to
get the catchability we want?
Mr. Drinkwater: Perhaps we will, yes. Certainly temperature affects
catchability, so you may be able to change things by varying the season. That
would require a lot of work, but it may be worth it.
Senator Butts: You did not mention shrimp at all. This is the one fish that is
overabundant right now. Will shrimp be affected as well? It is not mentioned in
Mr. Drinkwater: Yes, shrimp has been increasing because of good environmental
conditions, we think.
The Chairman: It has been a most informative session this morning. The committee
members all appreciate you coming over and talking to us about the impact of
natural factors other than fishermen. I want to note that we appreciate the
work you are doing at the Bedford Institute, along with other institutes of
Senator Meighen: I hope you get the funding.
The Chairman: It just shows that we have only actually touched the surface this
morning. You represent one of the many areas of science, so again convey the
message to your colleagues that we appreciate what you are doing and that we
hope your funding materializes and increases over the years. Thank you very
The committee adjourned.