Proceedings of the Standing Senate Committee on
Fisheries
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.
[English]
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 movements "meanders."
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 rings.
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 Stream itself.
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 effect.
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 positive correlations?
Mr. Drinkwater: Our feeling is that recruitment is not dominated by this process, and so one expects that there are other processes that control recruitment.
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 food.
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 fishery.
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 in 1965.
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 decreasing.
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 landings?
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 areas?
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 remain constant.
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 lobster.
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 landings.
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 my colleagues.
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 elsewhere.
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 fluctuations.
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 should do?
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 possibility.
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 moratorium.
Senator Jessiman: If it is overfishing, have we taken so much out that it can never recover?
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 again.
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 your paper.
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 that nature.
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 much.
The committee adjourned.