"FISHERIES SCIENCE PRIORITIES: might today's researchers be 'missing the boat?'" -- a letter of concern to the Government of Canada
To: The Honourable Herb Dhaliwal, P.C., M.P.
Minister of Fisheries and Oceans
From: Debbie MacKenzie
January 22, 2001
Dear Mr. Dhaliwal,
Thanks for your encouraging replies to my earlier correspondence. I remain very alarmed at the sad condition of our marine life. My biggest impression now is that THE POOR QUALITY OF THE SCIENCE available on the subject of the marine ecosystem is the most severe problem threatening fisheries today. “A sustainable approach to the resource” will never be achieved without a more accurate understanding of what makes the system “tick” - and all methods of resource management will become redundant once we have depleted all that can conceivably be eaten by humans or livestock.
Do you appreciate the severity of the present crisis in scientific knowledge in marine biology? (The public certainly does not, nor do they understand the implications for everyone’s future...but that’s not my main point today.) The science of assessing, managing and predicting changes in fish stocks is rapidly falling apart - the “best available science” cannot explain the changes that are happening in the marine ecosystem today.
The population models and management techniques that DFO (and marine scientists in other parts of the world) have been applying to “conserve” and manage fish stocks are proving to be less and less useful. It must be very frustrating. Lately it seems that their ability to predict trends in marine fish populations has been reduced practically to zero.
A wild, unsubstantiated claim? .....Maybe, maybe not...consider these examples and observations:
1. THE "3Ps" ATLANTIC COD STOCK STORY.
As you know, only this one of the Newfoundland cod stocks has shown any encouraging signs since the overall collapse in the early 1990s. “3Ps” borders the southern coast of Newfoundland so this stock lives much closer to shore than the others. And this one has shown signs of “rebuilding” - it has been very carefully watched and managed, since it would appear to hold out the best hope for the long-term survival of this fish, it has even been speculated that possibly the recovery of the offshore stocks as well may depend on the ability of the 3Ps cod to thrive and reproduce. So this one is critical. After a 3 year closure, the 3Ps cod fishery was cautiously re-opened in 1997. All the math was carefully checked to ensure that the stock “could” and would continue to rebuild after this point. But it is not happening as “predicted.” Now the 3Ps cod stock is suffering from a mysterious decline - “shocking” the Fisheries Resource Conservation Council (news story Dec. 22/00). Looked at in the context of what’s happening with all other groundfish in the Northwest Atlantic, this decline should come as no surprise - it’s only when one insists on viewing one stock in isolation (still the standard approach, unfortunately) that a disappearance of 3Ps cod is not “expected.”
A closer look at the 3Ps cod reveals more of the exact nature of the “surprise.” Although it’s a widespread trend, this one is seldom pointed to directly. What I’m referring to is the disappearance of the bigger, older fish - the individuals that have survived the early life stages. An accepted principle in fisheries science is that the risk of mortality is greatest for fish when they are young - obviously true since many perish as eggs and the larval stages and little juveniles are favorite foods for many species - once a fish like cod reaches the older ages/bigger sizes, vulnerability to natural predators is relatively very small. (Even the dreaded “seals” generally eat only the younger, smaller cod, those less than 4 or 5 years old.) The high vulnerability/natural mortality of young fish has led to a major amount of scientific study into all the factors that affect their survival. And perhaps an assumption that the older fish are so much stronger and less vulnerable has been part of the reason for the scant attention that has been paid to them. All of our groundfish stocks have been showing this trend: weights-at-ages have been declining, and the declines have been increasingly steep as the ages/sizes of the individual fish increase. I am convinced that this reflects increasingly poor feeding success of these fish, the nutritional stress increasing as they grow to bigger sizes (and higher trophic levels). (They are not “genetically” slow-growers, as has been suggested by some, partly because the tendency worsens as they age.)
Fish stock assessments in recent years reflect a constant theme of disappointment that year-classes of fish that looked promising in their youth, seemed to fade away much more quickly than expected when they age. In July 1999 (“Fisheries in Transition” ), the FRCC’s assessment of their best cod stock, 3Ps, included a comment on “age structure”: “1989, 1990, 1992 year classes strong” (page 147) In their report issued one year later (“Uncharted Waters” Sept, 2000) the note on “age structure” reads “no apparent strong year classes since 1989, 1990.” (page 87) The discussion includes “...there were indications in these data that the older spawning fish of the 1989 and 1990 year class may be fewer than suggested in the SSR.” The class of 1992 doesn’t even get a mention in the year 2000 - they should be mature spawners by now - yet they seem to have inexplicably disappeared? Do you see what is happening? For some reason the older fish are slipping away more quickly that “expected”...
How does the FRCC explain the recent “success” and “failure” of the 3Ps cod stock? Strangely enough, BOTH trends have been attributed to seals. In April 1999, the FRCC stated “...that the single cod stock in the Northwest Atlantic considered recovered, namely, the southern Newfoundland/St.-Pierre Bank stock (3Ps cod), is the only stock that does not have a large number of seals occurring within its stock range.” = = => fast forward approximately 20 months to December, 2000 and the decline of 3Ps cod, when the chairman of the FRCC explains to the press “This is most unusual...we’re not seeing the recruitment we had hoped for, and the fishing community is pointing the finger at the abundance of harp seals. We probably have about 5-6 million of those and that’s probably the biggest deterrent to stock recovery.” (So from the point of view of the FRCC, it seems that seals are “damned if they do and damned if they don’t”....‘nuff said, for now, actually there is ample evidence that seals are NOT a major factor preventing the recovery of the groundfish.)
Back to the puzzling disappearance of the older fish - that trend is much more acute for stocks farther offshore. Northern cod on the banks off Newfoundland and Labrador (2J3KL) (under moratorium since 1992) are now not surviving beyond FIVE years, the upper age limit in that population has been steadily dropping, and there’s not much scope to drop any further without literally facing extinction. If it drops by one more year it will mean the end of reproduction. And it’s not very far off. (Now, 50% of those cod are mature by age five, and 100% have disappeared by age six....a few decades ago they routinely lived beyond twenty years...)
I’ve seen no scientific explanation for this clear inshore-offshore gradient in fish survival today, but I can propose one: Inadequate nutrients are being returned to the ocean to replace the fish that we have been removing - the nutrients that do reach the sea get there primarily via freshwater runoff, whether they are from “natural” sources or human, and they are therefore available to fertilize or nourish the marine food web in nearshore areas only. That’s why 3Ps cod can “outproduce” the formerly huge offshore Grand Bank stock today. The inshore cod currently enjoy twice the life expectancy of the offshore ones. There has been one other Atlantic Canadian cod stock that has been able to rally slightly in recent years - the one in the northern Gulf of St. Lawrence - and again it’s down to better nutrient availability, in that case the proximity to the mouth of the river and the coast of Quebec. These inshore stocks are also severely weakened, but will survive somewhat longer than those further offshore.
2. THE BOOM IN CRUSTACEANS.
Scientists and fishermen alike seem to be pleasantly surprised by the current boom (historic highs) in populations of lobster, crab and shrimp in Atlantic Canada. Scientists warn that they expect these crustacean populations to eventually go into decline, but as you may realize, they really have NO IDEA beyond that - i.e. “when” will they decline, or “how severely?” or “what creatures will be dominant in the sea after that point?” There seems to be a general acknowledgement that the increase in crustaceans is somehow related to the disappearance of the groundfish...and perhaps an assumption that when the shellfish go down, that the fish will return(??) I’m sure that this is the hope, however there appears to be no evidence to support such a prediction. And maybe we should be doing something more than just “hoping”....
When groundfish abundance dropped in the 1960's after heavy exploitation, it doesn't appear that the age structure of the populations went into collapse (cod data tables from those years recorded fish up to 20 years old). Also the condition of fish seems to have increased rather than decreased at that time ("density dependent")...and unexploited species were not recorded as going into decline...and it did not result in a great boom in crustaceans...no, the 1990's are definitely not a repeat of the 1960's. "Hoping" for "stock rebuilding" like that which occurred 30 years ago...is far too likely to be in vain.
....Just maybe...the loss of the groundfish in the 1990s represents peeling off one layer, and when the crustaceans go into decline another layer will be removed. If my suspicion is right, and the whole system is being steadily forced down as the end result of all biomass extraction, then the future drop in the populations of crustaceans will definitely not be accompanied by a resurgence of the groundfish. Not a pleasant prospect, but it should be a possibility worth investigating all the same.
3. LEADING SCIENTISTS ADMIT TO BEING “BAFFLED.”
This is encouraging; it’s refreshingly honest. One newspaper headline last December read “Cod Death Rate Baffles Scientists” (The Halifax Herald, Dec. 21, 2000, story by Alison Auld, The Canadian Press) Subtitled “Number of fish dying off N.S. has doubled in last decade,” the story reported on a news conference with the director of the Bedford Institute of Oceanography, Mike Sinclair.
“The number of young cod dying in waters off the coast of Nova Scotia has doubled in the last 10 years, mystifying scientists who can’t figure out what’s happening to the fragile stock.” “Marine biologists suspect cooler water temperatures, natural predators and ultraviolet radiation might be affecting the vulnerable species, but they can’t pinpoint definitive causes.”
Actually the cold water theory has pretty well been refuted, later in the article it is mentioned that “temperatures have warmed in recent years.” And that is correct. For a decade or so the “colder water” theory seemed to be the favorite explanation for the failure of Atlantic Canadian fish stocks to bounce back once the fishing pressure was relieved...but recently it has been all but abandoned since the predictions of the theory (e.g. cod will grow better when the water warms up) have not come to pass. Beyond simply “cold water” a whole range of changes in environmental conditions have been investigated and attempts made to establish links to declines in groundfish. Many of these appeared promising at first, but then the correlations fell apart (for example: Sinclair, A. F. and Murawski, S. A. 1997. Why Have Groundfish Declined? pages 71 - 91 in J. Boreman, B. S. Nadashima, J. A. Wilson, and R. L. Kendall, editors. Northwest Atlantic groundfish: perspectives on a fishery collapse. American Fisheries Society, Bethesda, Maryland.)
Regarding “natural predators,” seals of course are the main suspects, but
“In the early days of the moratorium, fishermen said seals were destroying the once-bountiful cod stocks off Newfoundland. Sinclair says they likely play a role in the high death rate, but it might not be as large as people thought.”
...and seals cannot be causing the weight-loss trend in fish that I have previously pointed to, nor can they be causing the total eradication of the older year classes of fish.
Ultraviolet radiation? The theory is that with the thinning of the ozone layer, that the increasing level of ultraviolet radiation may be damaging the fish larvae. And they have been proven to be somewhat vulnerable to this - in their early life stages when young fish are not well pigmented and are living very close to the surface - however it’s quite a stretch to think that dark brown codfish, five year old bottom dwellers on the offshore banks...are now succumbing to “sunburn.” (Also this is another theory that completely fails to account for the inshore-offshore trend...)
“The findings have baffled experts who expected the stocks to rebound after a moratorium was imposed on the species in the early ‘90s. At the time, scientists suspected cod was being fished to near extinction and needed a reprieve to recover. But 10 years after the suspension, the stocks are still collapsing and scientists say they could be facing a new, more elusive problem. ‘They’re dying when they’re quite young - as juvenile and young adult fish - and at a much faster rate than what we expected,’ said Sinclair... ...He said the changing ecology has also made the cod ‘a lot slinkier, skinnier fish and in worse condition.’”
So it is now obvious that the cod need something more than a “reprieve” from fishing to recover (although that was certainly essential.) Mr. Sinclair hinted at what else is needed when he described “a lot slinkier, skinnier fish and in worse condition” - those are the clear signs of malnutrition, the other thing that the codfish need is FOOD.
4. MORE TOUGH PUZZLES.
Marine biologists have found themselves facing new and unexpected challenges in the last couple of decades. One major challenge that they are just beginning to grapple with is “ecosystem management.” They know that it’s what they need to do - look at and “manage” the thing as an overall system of interdependent parts - but this aspect of the science is clearly in its infancy. There are no useful “ecosystem models” and scientists are just now starting to do the groundwork in assessing “what” needs to be done and “how” it should or could be done. Scientists in Atlantic Canada are certainly doing as well as or better than those elsewhere in the world, and they barely know where to start. (“Proceedings of a Workshop on the Ecosystem Considerations for the Eastern Scotian Shelf Integrated Management (ESSIM) Area, Bedford Institute of Oceanography 19-23 June 2000. CSAS Proceedings Series 2000/14)
The increasing natural mortality in the cod stock that was reported in the press - is accurate, but does not tell the whole story. “Mortality” has been inexplicably rising in ALL groundfish - check the Stock Status Reports from DFO, or the publications of the FRCC.
Another unexpected puzzle has been why the “density-dependent size of fish” principle fell apart. A predictable characteristic of fish stocks that had been known for a long time was that in years of high abundance of a particular fish, the individual fish in the group would be smaller than average. Conversely, in years when the numbers of fish were low for any reason, the individual fish in the group would be exceptionally large and well-fed. This was believed to be a reflection of differing numbers of fish competing for the same amount of food. From the mid-1980s on (actually earlier than that for the bluefin tuna) it became obvious that dropping abundance was no longer associated with plumper fish - strangely, the size and the numbers of the fish were, and still are, declining simultaneously. One theory was advanced to explain the recent slow growth in fish - “size-selective culling effect of fishing gear” - this cannot be proven, however, and the pattern of decline is consistent across heavily exploited, lightly exploited and never-exploited species in the Northwest Atlantic (and elsewhere)...so a direct link to the effects of particular gear types on particular fished stocks...is quite unlikely to be a primary cause. On the other hand, my explanation of a system undergoing a steady, ever-worsening loss of overall biomass, with a gradual reduction of food available in the system - does offer an explanation. Less food = fewer fish AND smaller, skinnier fish....
The reason that fish size is no longer “density-dependent” and the explanation for many of the other recent “surprises” in the marine ecosystem is this: A fundamental error was made in assumptions about how the system works, and the error was made early in the development of fisheries science, and incorporated into the later thinking. It was ASSUMED that an unlimited reserve of raw materials exist in the ocean to replace fishing removals - hence “species replacement theory” and “the total biomass will always remain the same/it’s just a ‘regime shift’” sorts of ideas. What has happened is that fishing (overall) has interrupted the marine nutrient cycle (a living system that depends on constant recycling of nutrients). The effect has been cumulative, and now sea life forms - more acutely those living at the higher trophic levels, like bigger fish - are suffering from a shortage of available nutrients. (Evidence? - there are now very few of them and they are in poor “condition.”) The implications of this are very serious since any and all fishing will ultimately worsen the overall problem...is that a reason to ignore it? Whether or not we “like” a theory is irrelevant - all that matters is if it can accurately explain and predict changes that take place.
5. THE NEED FOR RESEARCH IN NEW DIRECTIONS, INCLUDING A FEW CONCRETE, CONSTRUCTIVE SUGGESTIONS.
As you are aware, I have spent the last few years conducting my own “freelance” research into the problems with the fish stocks. My original work that I sent to you last year (“Wake Up and Feed the Fish! A New Insight into the Causes of the Collapsing Fisheries”) described the situation as I saw it. I tried to show how the trends that are occurring seem to support a new explanatory theory - overall biomass depletion in the sea is the cumulative end result of fishing - and the steady biomass drop is now a major “forcing mechanism” driving many of the changes that we are seeing in the marine ecosystem today. What needs to be done now, and what I have been working on, is this: a critical look needs to be taken at all of the other explanatory theories that are being used today. This list includes overfishing, climate change, pollution (nutrient and chemical), habitat destruction, increased ultraviolet radiation, excessive predation by seals, “size-selective culling has induced slow growth in fish” and “species replacement occurs in the sea, keeping the overall biomass steady.” The strengths and weaknesses of each theory (and combinations) need to be objectively described, and then today’s theories need to be held up against today’s trends to see how well they fit - i.e. their ability to offer plausible explanations, and also their ability to accurately predict developments.
That is what I have tried to do. I’ve gathered a great amount of information ("references galore") and am in the process of writing up my findings. But it’s a huge project and will take some time for me to finish....and I think it would not hurt for me to give you a sneak preview of my conclusions. It might be helpful in determining the most useful direction for the investigations that need to be done by other scientists. I have tried to look at the many trends in the changing ecosystem and all of the explanatory theories. I have found that a few trends stand out as lacking any (proven or unproven) explanations. The changes in fish stocks that are the hardest to explain using today’s accepted theories are the following (the first three I’ve already mentioned):
THE LOSS OF THE BIGGER/OLDER FISH
This is dramatic. And it’s well-known, ask any fisherman or scientist, fish are
getting smaller and smaller everywhere. To a fairly large extent this reflects the fact that
they are younger, although they are also in significantly leaner condition. To illustrate the
disappearance of the elders, here are two data tables from DFO, the first one for the
heavily exploited Northern cod stock, and the second for the not-very-heavily-exploited
arctic charr. (These are small files, I mainly want to show the increasing absence in later
years of the older age groups - if you want to see the level of detail where you can read all
the fish weights click “here” for the larger files.)
Many, many fish stocks have recorded data sets that are very similar to these two. Even “unexploited”
species show the same pattern. I find these data tables worrisome. I’m very bothered by the
question of “what happened to the big fish?” These data tables show an important part of
the picture and help to answer the question “What does a collapsing fish stock look like?”
Well, we do know what it looks like - it looks like the cod and the charr and the multitude
of others, and they clearly undergo population collapse from the top down. When the
2J3KL cod disappear - as the trend indicates that they will - it will be because the life
expectancy of an adult has dropped below the age of sexual maturity. (Currently both of
these are at the age of five years, a most precarious situation for this fish, to say the least.)
So the cod population will end after reproduction ceases, and this will inevitably be due to
the disappearance of the bigger fish, and not primarily due to the mortality rates
experienced by eggs, larvae and juveniles. Realizing this, I find it puzzling that cod research
today is almost exclusively focused on those youngest life stages. Look at DFO’s list of research papers from 2000. I do
not see any study focused on the question of “what’s causing the disappearance of the big
fish?” But there are quite a few documents in the list that describe studies of factors
affecting larval and juvenile stages. (There seems to be an exception where adult fish are
sometimes tagged in efforts to determine their migration patterns - looks like “right fish,
wrong question” to me.) I also looked at the cod research being conducted at Memorial
University in Newfoundland. The “Fisheries Conservation Chair”
there describes its mandate as “to develop an
independent fisheries research program to complement and scrutinize Government
programs and provide an integrative focus for fisheries reserarch at Memorial University.”
On the top of their focus list is this one: “The
collapse and rebuilding of groundfish stocks in Atlantic Canada.” Sounds good. But a look
at their “cod research” page reveals this:
“The life history of cod is a major focus of our research effort. Despite its economic
importance, the life cycle is not well understood. Our research questions concentrate
mainly on the parts of the lifecycle shown below. Please click on your choice to view our
research in each part.” There’s a nice diagram of the cod life cycle, and clicking on “Eggs
and Larvae” or “Juveniles” links one to lists of the appropriate research projects....however
try clicking on “Adult.” I did, and it’s not even a link...
So, Mr. Dhaliwal, mortality of young adults now clearly exceeds juvenile mortality as a threat to cod. That’s my observation and surely it should inspire a few new research questions.
While on the discussion of the disappearance of the bigger fish, I’d like to point out that the ecosystem as a whole also displays this same trend. This is also well known, for example many people are aware of the drastic declines being experienced by large fish such as bluefin tuna and swordfish. But it’s always blamed on “overfishing,” with the explanation that fisheries have been targetting the bigger ones and killing them at a faster rate than they can be replaced by juveniles. That could be so, but a close scrutiny of the picture reveals that the selective “killing off of the big ones” is not only happening within species but also BETWEEN species. And that definitely hints at a systemic driving force, something going on in the system as a whole that stresses big fish more severely than small fish. As an example, here’s the skate story...actually it’s an excerpt from one of my other articles on this website, “Floundering Around in a Starving Ocean.”
And look at skates. A family of skates exists in the Northwest Atlantic and all have been caught mainly as bycatch in the commercial fisheries. Until recently they were considered to be more or less “trash” - no value except that a few were used in fishmeal production. Now there is a directed fishery for some skates as there is a market for “skate wings.” In Atlantic Canada the common skates include, in order of increasing size: little skate, smooth skate, thorny skate, winter skate and barndoor skate. (A recent directed fishery for winter skate has been determined to be “not sustainable” which is no surprise for a number of reasons, one being the low reproductive potential of this type of fish... another being the disappearance of essentially all other fish in the area.)
The recent big “skate story,” however, has been the virtual extinction of the barndoor skate. Like the others, it has been frequently caught as an unwanted bycatch in fisheries. But for some reason the barndoor skate has found itself much more vulnerable to depletion by this method than it’s cousins. The range of the barndoor was as wide as the others, and it was not “rare.” In 1966 it was described as “very common at Tignish, PEI, frequently at Canso, N.S., and along the Nova Scotia coast, all parts of the Bay of Fundy and St. Mary’s Bay...offshore at Banquereau and Sable Island Bank...to the southern edge of the Grand Bank...” What sets the barndoor skate apart from the other skates? It is mainly size - the barndoor is a remarkably larger skate than the others. It used to grow up to five feet wide.
A comparison of the diets of the various skate species shows that the barndoor skate relies much more heavily on a diet of “fish” than do the others. This tends to be the case with all fish as they grow larger, and the barndoor needs to be larger than the others to reach reproductive size. A shortage of finfish in the sea would therefore have a bigger impact on the biggest skate. The diet of the barndoor? According to the scientific research they eat “bivalves, squid, rock crabs, lobsters, shrimp, worms, and ‘a long list of fishes’ including spiny dogfish, alewives, herring, butterfish, sand lance, cunner, hake, silver hake, and flatfish.” The diet of the smaller skate species? From the same source “hermit and other crabs, shrimp, amphipods, annelid worms, bivalves, and ‘some fishes’, sand lance, herring, cunner, alewives, tomcod, and flounders.”
Does any evidence exist to support the idea that the barndoor skate is disappearing because of starvation? As much as I would like to, I do not expect to find statistics on “condition factor” for the barndoor skate. Perhaps, however, some clue can be deduced from a comparison of pictures of this animal. Not a “scientific study,” to be sure, but illustrations of the barndoor skate that were done decades ago (this illustration from NOAA's historic collection - at least 100 years old) show a noticeably plumper mid-section than one I found that was done in the 1990s. The later sketch gives the impression that the fins are getting bigger...but of course it is the same illusion that can be seen in other severely stressed fish species (e.g. the basking shark - see illustrations on the bottom of my home page)... the fins are the same size as ever, it’s really the body of the fish that is getting smaller.
My conclusion is that “fishing down the web” has proved to be too big of a challenge for the barndoor skate. “Size-selective culling?” Yes, it has occurred within the family of skates...and it cannot be due to “fishing methods” in this case - they all ran the same risk of perishing as “bycatch,” size-selective culling is the result of size-dependent feeding patterns. The big ones starve first.
So, if the disappearance of the bigger fish cannot confidently be blamed on overfishing (on a stock by stock basis as it always seems to be interpreted), then what can it be blamed on? (The continuing decline in the size of the not-fished Northern cod also discredits stock “overfishing” as the driving force in diminishing fish size - since cod fishing has stopped and the size decline continues...) How could an environmental factor like pollution, climate change, UV radiation level, or physical habitat destruction allow the survival of 3 year old cod, for instance, while being 100% lethal to 6 year olds? ...And seals? How could seals, which are known to preferentially eat smaller fish (20 - 30 cm long)...how could they possibly devour the entire population of five foot wide barndoor skates?!
The single factor that makes a bigger cod or other fish more vulnerable than a smaller one is where in the web they must necessarily feed. None of the other theories are credible as selective killers of big fish. There is a food shortage in the sea, and surviving at the higher trophic levels is becoming increasingly impossible for fish, especially on the offshore banks. While reading about the many stocks that are exhibiting constantly reduced age ranges, it is not uncommon to encounter a positive note like this: “the 1998 year class appears to be exceptionally strong” - this of course is based on a survey when they are one or two years old - and too many times it becomes just another “unexpected” failure as it quickly fades away when the “year class” tries to grow up. A high number of juveniles may be just another reflection of the dropping average trophic levels in the sea, one aspect naturally being a shortage of their natural predators. How does a fish actually slide into extinction? Possibly it’s with “an exceptionally strong year class” that starves to death before it reaches the age of maturity? ...In any case, we’ll know soon.
THE INSHORE-OFFSHORE SURVIVAL GRADIENT
I have described this trend before.
“Better inshore/worse offshore” is epitomized by the Northern cod stories, but is also
widely evident in others both on the East Coast and the West Coast. When the same animal
normally lives in both inshore and offshore locations, the argument becomes stronger. A
prime example on the West Coast today is the case of the Steller Sea Lion (photo: ADFG). These
fish-eating marine mammals live along the coast of Alaska. The sea lion habitat area
includes the continental coastline of Alaska as well as the Aleutian Islands - a chain of small
islands that extends very far out into the North Pacific ocean. There has been a fair amount
of media attention in the last couple of years covering the dramatic decline that is being
experienced by the western end of the steller sea lion population. It appears that they are
starving, and the population has undergone a very steep drop in numbers. In contrast, the
steller sea lions living on the coast of the mainland seem to be maintaining their numbers
fairly steadily. Not really a mystery, this can easily be explained by “better inshore/worse
offshore,” starvation becoming more severe the farther away one moves from the source of
nutrient input (the freshwater drainage from the mainland - the Aleutian Islands are much
too tiny to offer a significant contribution).
Changes in the ranges occupied by fish stocks start to make sense when viewed in this light. Reading through the scientific reports on East Coast fish, I constantly encounter this theme. Examples: pollock - 3Ps - recruitment shows “positive signs inshore,” American Plaice - 4T - “this stock has been increasingly concentrated in the eastern part of 4T in recent years” - this flatfish stock lives in the Gulf of St. Lawrence and appears to be at an all-time low, and a look at the map indicates “why” it might move to the eastward, a move in that direction puts it more directly into the path of the outflow of the St. Lawrence River. One last comment on the “inshore” advantage as it applies to cod: recently acoustic studies have been done to determine where the fish are concentrated. Look at this document from DFO, it includes good maps, “Distribution and abundance of Atlantic cod from an acoustic survey of Bonavista Bay - Trinity Bay, Newfoundland during the fall of 1999" The only “substantial aggregation of cod was detected in Smith Sound, Trinity Bay” - a look at the map indicates that Smith Sound is about as far INSHORE as a codfish can swim.
So there you have it - another suggestion for a sensible research focus - what is the driving force behind the shifting ranges of stocks of marine life? Investigate the connection to nutrient availability - there’s ample reason to suspect it. A very close look needs to be taken at the marine nutrient cycle to discover where the weak links are. (I have already done a lot of work on this and will share the details with you later.)
THE ENDING OF “DENSITY-DEPENDENT” GROWTH RATES IN FISH
I have already described this particular change in fish (under “More Tough
Puzzles”). It is another absolutely widespread pattern, and the scientists have certainly been
aware of it and making attempts to explain it. Nothing much has been offered as
explanation for this, other than the suspicion that it must have been caused by an
“environmental” factor. “Poor environmental conditions.” True, the fact that all fish are
affected suggests something systemic, but the investigation into suspected “environmental
factors” has not turned up one that is plausible or convincing enough to explain the severe
and persistent downturn in the health of the stocks. I also think that the cause can be
described as an “environmental factor,” but it’s one that has received no attention yet:
systemic, overall biomass depletion. Studying one fish species at a time will not reveal this,
and by and large that is still what our scientists are doing. Those looking at “environmental
factors” still seem to be investigating the standard list - water temperature, salinity, etc.,
including searching for connections to obscure long-term weather patterns like the “North
Atlantic Oscillation.” Those are doubtless worth looking at, but so are the points that I have
THE DECREASING TREND IN AGE AND SIZE AT MATURITY
Fish now have a tendency to reach sexual maturity and reproduce at younger
ages/smaller sizes than they did in the past. This is another well known and documented
trend, and another puzzling change in fish stocks. When I first came across this one, I
didn’t believe it - what I wrote in 1999 was that I suspected that errors had been made in
“ageing” stunted fish, that an actual lowering of the age of maturity was most unlikely.
Now I know that I was wrong about that - there is overwhelming evidence that the age of
maturity has indeed been dropping in many, if not all, fish stocks. This can only be stated
with certainty in species where ageing methods have been developed, but in the others it is
strongly inferred by the appearance of roe in smaller fish than ever before.
Why would stressed fish stocks mature at increasingly early ages? It’s another tough one. It was noted decades ago that cod on Georges Bank, for example, grew much more quickly and matured faster than cod farther north, like those on the Grand Bank. It is likely that warmer water temperature provides part of the explanation since fish like cod clearly do “feed better” in the warmer conditions. On Georges Bank cod always grew bigger, faster than they did farther north. When they get bigger the rate of growth slows down. I wonder if it - the trigger for puberty - has something to do with the growth rate. When growth slows to a particular rate, as it does when fish begin to reach the larger sizes...maybe that somehow triggers the diversion of energy into reproduction instead of somatic growth. Maybe now that growth rates are slowing overall, the trigger kicks in earlier(?) Just speculation, mind you, I do not claim to understand or be able to explain this one. However, neither do the other theories.
I have just one more observation regarding the decreasing age/size at sexual maturity. Our shellfish stocks are constantly being described as “very healthy” these days - lobsters and shrimp galore, big money - but beware...the strange pattern is developing there as well, eggs are appearing in smaller lobsters than ever before...
5. THE “PRECAUTIONARY APPROACH”
This principle - that complete scientific proof that something is harming the marine ecosystem shall not be demanded before conservation measures are implemented - should demand an investigation into the validity of my “theory.” Also, one reads now in fisheries management literature the frequent buzzphrase “reversal of the burden of proof” - meaning, I think, that those who are carrying out a potentially harmful activity - the onus is now on THEM to prove that harm is NOT being done, rather than on those who are concerned that harm might be being done. (Therefore I am formally requesting that the fishing industry provide “proof” that removing fish from the sea is NOT resulting in nutrient depletion on a systemic scale. That, of course, is an impossible bill for them to fill...so we must still have something lacking in our conservation policies.)
As for myself, I have spent several years investigating these problems and have gathered enough supporting evidence to “prove” that my ideas deserve a serious look. In 1999 I self-published “Wake Up and Feed the Fish! - A New Insight into the Causes of the Collapsing Fisheries” and sent umpteen copies to scientists and fisheries managers in an attempt to start a debate. A year ago I made this website dealing with the same issue ....what I have been trying to do is “reverse the burden of proof” from myself to the recognized specialists in the field. But it’s proving to be a very difficult thing to accomplish. I’ve received a lot of interesting feedback from scientists and others...but no-one seems to want to REALLY investigate the problem...could it be that no-one wants (or “dares?”...or “is permitted?”) to rock the boat quite that hard?
I have had some helpful feedback from the director and others at the Bedford Institute of Oceanography, but feel that the question has not received the serious attention that it deserves. It is possible that I am seen as naieve and not “qualified” to comment...but the experts are now openly admitting that they, themselves, do not understand what is going on.
I may sound as if I’m being unduly hard in criticizing the current science programs and the work of the FRCC. That is not my intention. Individual DFO scientists have been very helpful to me, and one impression I have of the department as a whole is that it is much more open in sharing it’s information than any other similar department in the world. But there is definitely a problem there. It must be the bureaucracy - I think that you have some very bright scientists there, but the way DFO works is to confine them to little boxes - each one to his specialized work area - and the whole thing shuffles along like it always has, checks and balances in place guaranteed to maintain the status quo. None of the scientists in the little boxes are given the responsibility for “making sense out of everything,” and those in the higher positions are so overloaded with management responsibilities that they cannot get much else done. But perhaps I could be wrong; I do not claim to have studied “DFO” itself in as much detail as I have studied the trends in the fish stocks...
And regarding the FRCC. I have seen them criticized as being “industry dominated.” And I also suspect that may be true. But I have found that just because a person’s livelihood depends on fisheries, he will not automatically be resistant to ideas like mine (which are very threatening, no doubt). It was one of the “industry” representatives that invited me to speak to the council. And he is not the only one who has told me that he is more interested in knowing the truth and preserving something for the future, than he is in pushing up today’s quotas regardless.
So, Mr Dhaliwal, that’s the major issue as I see it. The ever-worsening weakness in the marine science must be dealt with - it’s time for a complete shift in thinking, scientific investigators must become...or be given permission to become...more open-minded and consider all possibilities, regardless of how unpleasant they may be. I have tried to give you some specific “pointers” and I hope you find this helpful.
January 22, 2001