Thinking “outside the box”
…in the case of the mysterious loss of the Canadian cod stocks
by Debbie MacKenzie, February 6, 2003
A letter to the Minister of Fisheries suggesting a relationship between the ever-declining fish stocks, the failure of science to explain exactly what is happening, and the overlooked significance of “biological forcing” of marine primary production.
The Honorable Robert
G. Thibault, P.C., M.P.
Dear Mr. Thibault,
The Fisheries Resource Conservation Council (FRCC) has recently expressed its alarm at the increasing deterioration of the Eastern Scotian Shelf ecosystem, and has described the cod stock there (4VsW) as being in “free fall.” The council has urgently recommended the establishment of a multi-disciplinary task force to address factors related to “the poor productivity regime being experienced on the Eastern Scotian Shelf.”(FRCC.2003.R.1) I trust that you will make this a high priority, and I believe that I can offer some useful insights. A basic re-examination of exactly what drives marine productivity is my suggested starting point.
The key question is whether or not the players in the intricate ocean food web have devised ways to actively increase their own growth potential by working to physically transport and deposit fertilizer near the sunlit surface, thus enabling increased growth of the small plants (phytoplankton) on whom the entire web depends for energy. This active fertilizer lifting is the process that I refer to as “biological forcing.” If the many interdependent forms of marine life have long collaborated in boosting total production in this manner, then it follows that their removal may reduce the total energy and productive capacity of the ecosystem as a whole (i.e. fishing might have the potential to induce a decline in marine primary productivity). The question can also be thought of as “do living marine animals work to increase the amount of food that grows for them in the sea by actively fertilizing their 'vegetable' garden?” I see a lot of evidence that suggests that they do.
But surprisingly, this question has not been a focus of marine research to date, and the currently used fishery “population models” (which are collapsing along with the fisheries) make no allowance whatsoever for this type of dynamic to be affecting production. The belief that is entrenched is that the total amount of food produced in the sea relies only on patterns of weather and water movements, on “physical forcing.” And this represents an important “box” that fishery science urgently needs to step outside.
I will return later to more discussion of this problematic “box,” but would first like to take a look at the FRCC’s “major concern,” the status of the 4VsW cod stock, the state of DFO’s knowledge and research focus in this area, and my frustrated attempts to join in the debate.
In its latest publication the FRCC has repeatedly and specifically pointed out that “food availability” is one factor that must be reviewed in relation to the poor productivity of this cod stock. The food factor, however, is one that DFO has been largely neglecting, and maybe is at a bit of a loss for how to evaluate. (Surveys on the abundance of the multiple smaller species eaten by cod have not generally been done, so this potentially useful data does not exist. Without access to “how many food items are in the environment that are available for cod to eat,” analysis of cod stomach content data will be the most useful. Regarding 4VsW cod, apparently DFO has over 40 years of this data, which will soon be reported for the first time. I urge you to keep an eye out for this publication. (Harris. L. E. and L. P. Fanning. 2002. Compilation of fish diet data from the Scotian Shelf and Bay of Fundy (1958-2001) Can. Tech. Rep. Fish. Aquat. Sci. (still in prep).)
For five years I have tried to engage DFO scientists in dialogue on the issue of the mounting starvation that is affecting marine species, including cod. Most recently I have included on my website photographs of grossly emaciated cod (caught on the ESS during summer, 2002), fish with empty stomachs and an unusually twisted body shape, apparently from forced bottom-feeding due to a shortage of prey fish. I find this to be bizarre. See my article: The Downturn of the Atlantic Cod - I have offered my proposed explanation for the cause of the unusual shape of the cod, but have no idea what DFO Science makes of it, or if they have an alternative explanation, because they have refused to comment. Look at the photos; what is your impression? Really looking at these fish can leave no doubt that food shortage is a major factor, probably “the” major factor shaping their fate.
I have reviewed many of DFO’s publications regarding 4VsW cod in recent years and have seen no mention of the altered body shape of cod, and relatively little attention to the poor “condition” of the fish, although it is so severe that these cod are commonly described as “slinky.” But there has been an increasing preoccupation with the role of seal predation, a line of inquiry which holds no promise of solving the underlying issues.
For instance, in 2001, in the Canadian Journal of Fisheries and Aquatic Sciences, a trio of DFO Scientists published “Why the Atlantic cod (Gadus morhua) stock off eastern Nova Scotia has not recovered.” (Fu et al. CJFAS 58:1613-1623) While increased cod mortality due to “reduced condition” (starvation) is mentioned in the introductory discussion of collapsed cod stocks in the northern Gulf of St. Lawrence, Labrador and Eastern Newfoundland, the focus of the 4VsW inquiry is “a model based on a framework of interactions between cod, fisheries and seals,” and it is concluded that seal predation mortality is “an important factor affecting the survival of immature cod.” This suggests to the reader that seals are harming the cod stocks, and appears possibly to be an effort to lay the groundwork to scientifically sanction what the fishermen want to do, which is kill the seals. But how sound is this?
Seal sympathies aside, consider the uselessness of including only seal consumption in estimating the effects of “predation mortality.” Surely it cannot matter to a young cod whether it is consumed by a seal, a shark, or a large cod, halibut, or other large fish. These are all natural predators which have killed small cod on the Scotian Shelf for eons. While the number of seals has increased in recent years, and the tonnage of small cod eaten by them has (possibly) increased as well, these mathematical exercises consistently fail to consider the declining trend in other sources of predation mortality for small cod. The big fish that once consumed small cod, in competition with the seals, have now all but disappeared. Seals mouths are up somewhat, but big fish mouths are way down. Witness the recent drastic decline in numbers of sharks in the NW Atlantic. Groundfish, including cod, big enough to eat small cod are no longer found on the Eastern Scotian Shelf. How many million cod-eating fish are now missing from this picture? Focusing only on an increase in seal predation, while ignoring a possibly much larger decline in large fish predation, makes the whole exercise so biased as to be meaningless.
A more open-minded look at the effects of seals on cod stocks may well reveal that they do far more good than ‘harm’ (see: Seals and Cod ).
The most ominous trend in the cod stocks is not the disappearance of small cod to seal predation, but the increasing natural death rate of mature fish. (Fu et al, 2001) And, I would add, the obvious malnutrition of the adults. Mature cod appear to be dying of starvation. (For more details and photographs see: The Downturn of the Atlantic Cod ) Since a codfish will eat ‘anything and everything,’ their individual failure to grow now implies that that is what is missing, 'anything and everything,' and therefore that total food production in the ocean is what is really declining. This is very serious, and I have been disappointed to find that DFO Science will not budge in their refusal to address it.
I wrote to you last year expressing similar concerns, and pointing out the existence of concrete evidence of a decades long declining trend in marine primary production in our coastal waters. At that time, I asked you to look at the evidence of a dramatic decline in barnacle growth on the open coastline, and described the refusal of DFO scientists to comment on this. In your response to me (July 16, 2002) you assured me that “this is a priority area of study for Department of Fisheries and Oceans scientists” and suggested that I could confirm this by reviewing several websites containing government marine science publications. Already aware of those websites, I reviewed their contents again (and much more), and I can assure you that assessing these signals of declining primary production is not now a direct focus of DFO Science inquiry. Nowhere have they addressed what I am pointing out: that long-term declining trends in foundation species, coastal organisms such as seaweeds, barnacles, and mussels, strongly suggest an ever-lowering of overall levels of marine nutrient cycling. These changes are not trivial, and they are not in my imagination. DFO scientists are not looking for declining primary production, and they are not monitoring these changing indicators. Neither are they investigating the pathways that most likely lead to biological forcing of marine production. Why not?
There is now a major scientific effort to link changes in marine productivity to climate change. While this is certainly a possibility, data from Atlantic Canada simply do not make a convincing argument that “climate change” is at the root of the current problems. For instance, slowed growth of groundfish was blamed on unusually cold water in this area in the late 1980s/early 1990s. Fish growth was predicted to improve when the water warmed. But water temperatures have been at or slightly above long term means for at least 5 years now, and the fish growth continues to decline. (This is one example of what I mean by “collapsing models.”)
Today’s scientific preoccupation with climate effects was evident in your comment to me: “Understanding the marine ecosystem and the impacts of climate change requires decades of observation, integration of physical, chemical, and biological data, and modelling.” As if the decline in primary production that I was concerned about could only be an effect of “climate change.” Nobody is asking whether or not the decline in primary production might be an effect of fishing, and that is my strongest hunch.
Why do marine scientists stay inside this “box” and limit their thinking to “climate change,” while never questioning fishing as a possible cause of declining marine primary productivity? It seems to be because “classical oceanography” has taught them that the amount of plant fertilizer that is lifted to the surface water, and which determines net primary production, depends entirely on water movement patterns which cause mixing of the water column. Since water movement patterns clearly do respond to changing climate variables, it follows that climate change will have a direct impact on the rate of primary production. This is known as “physical forcing” of biological production. This surely occurs and profoundly affects marine production, but it is also surely not the whole story.
One fishery scientist told me that this concept of the ultimate determination of marine primary production by “physical forcing” was “the foundation of fishery science”…well, if that is so, then I am afraid that there exists a crack in that foundation…which just might be big enough to explain ‘where’ the formerly great fish populations have gone…
This line of inquiry (into the processes of “biological forcing” of new marine production) has not been adequately investigated, yet it has the potential to go a very long way towards explaining today’s problems with the fish stocks, and specifically in answering the question of why there has occurred a failure of “food availability” for fish, in the absence of significant change in climate/physical forcing. In articles posted on my website I have discussed several pathways leading to biological forcing of marine production, some obvious (floating spawn) and some more speculative (vertical migration of zooplankton: large gaps in basic knowledge make it impossible to rule out the intriguing hypothesis that these tiny organisms, key players in the ocean food web, contribute to biological forcing by lifting nitrogen to surface waters…I find this idea fascinating.) But again, my attempts to engage DFO Science in discussion on these points have been fruitless. I realize that this is not how these scientists are accustomed to thinking about marine production, but no matter, their dismal record of failed predictions over recent decades suggests that something important is missing from their models. I also realize that if biological forcing proves to be an important driver of marine production, that concepts of "sustainable fisheries" and "renewable resources" will be necessarily changed. My request for a meeting with the director at BIO to discuss these issues was met with a flat refusal.
You suggested that I should “present and discuss my ideas with colleagues at scientific meetings.” This, however, presents a real difficulty for an independent researcher like myself, especially one who is bucking the mainstream. I find that my input is not welcomed, and I am most often ignored. My lack of the usual background and formal employment as a marine scientist works against me in this regard, although I am convinced that it works more importantly to my advantage in allowing me to think independently and to consider novel approaches to shedding light on today’s problems.
The biological data in the cod science overwhelmingly supports the hypothesis that declining food availability is shaping the ongoing trends. (Declining growth rates, poor “condition,” declining size and age at maturity, heightened vulnerability to environmental stressors such as cold water, greater cod survival in areas with relatively higher rates of primary production (e.g. the Bay of Fundy, and 3Ps, which always grew cod more quickly than the Grand Banks), declining zooplankton…) The problem seems to be that, while the data supports a long-term general declining trend in primary production, the “theory” does not. However, “when theory clashes with reality, reality always wins.”
Turning a blind eye to the possibility that significant biological forcing of marine production most likely occurs, allows us to continue to believe that our ongoing harvesting of marine life will not, and has not already, damaged the ecosystem at the fundamental level of its productive capacity. DFO Science needs to wake up now, step "outside the box,” and take a hard look at this question.
The public has seen enough of the “Cod stocks continue to decline, scientists baffled” type of headlines. It is time to expose more of the truth, however unpleasant, to the public, including the fact that food shortage is now the critical issue for many cod stocks in Atlantic Canada. “Unexpectedly” these fish are starving, because, also “unexpectedly,” the overall food-production rate of the ocean has been dropping…but the implications of this ominous negative change in the marine environment can confidently be expected to extend to all other marine species, including fish, marine mammals and seabirds. The public would be very concerned if they accurately saw this picture. And I think they deserve to see it.
Aside: Have you noticed that the endangered right whales no longer bother to make the effort to move onto the Scotian Shelf? The survivors have shortened their migratory route as much as possible and now concentrate on feeding in only the richest part (Bay of Fundy) of their former range (Scotian Shelf, Gulf of St. Lawrence). Despite these energy conserving measures, the right whales are showing increasing signs of being stressed by a lack of food (lengthened calving intervals, poor physical condition, last summer they showed up on the feeding grounds a month earlier than usual(!)). Since the topography and water movement patterns of the Bay of Fundy maximize natural productivity in the area (by “physical forcing”), many species formerly widespread in Atlantic Canada can be expected to make their last stands there (right whale, Atlantic cod, barndoor skate, cusk?…lobster?…and how many others?) But even the fantastically productive Bay of Fundy is apparently experiencing a significant declining trend in total production (for instance, look at the long term declining trend in growth of 4X haddock, but there are many other indicators…the right whale and the barnacle alike make useful “plankton production monitors” and both appear to be signaling the ongoing downward trend in the Bay of Fundy.)
Who will you appoint to the task force to study the riddle of the low productivity regime of the eastern Scotian Shelf?
I would very much like to meet with you to discuss these issues when you next visit the Halifax area. Might this be a possibility?