Grey Seal Conservation Society (GSCS)
Position statement against the Canadian harp seal hunt
March 14, 2005

Advice to Ocean Ecosystem Managers: Trust the seals, fear the microbes…

To:       The Honourable Geoff Regan
            Minister of Fisheries and Oceans, Canada

            The Honourable Stéphane Dion
            Minister of Environment, Canada

The Grey Seal Conservation Society (GSCS), a non-profit organization based in Atlantic Canada, urges the Canadian Department of Fisheries and Oceans (DFO) and Environment Canada to bring an immediate end to the commercial harp seal hunt.

The Canadian harp seal hunt is ecologically damaging on two fronts that seem not to have been considered by DFO: (1) An unprecedented, drastic loss of natural marine predators has already occurred. Because major change of this nature can destabilize a marine ecosystem, no more large fish predators, including seals, should be removed at this time. (2) If the seal hunt is not banned outright this year, a minimum precautionary directive from DFO and Environment Canada should immediately forbid sealers from abandoning seal corpses to rot in the Gulf of St. Lawrence. Sealers now routinely discard massive amounts of rotting dead seal flesh in an ocean area with oxygen-poor bottom water, contributing to polluting and further degrading the marine environment.

The seal cull approach to “cod recovery,” although strongly favoured by the fishing industry, is naïve, and is based on outdated myths about predators in general, and on misperceptions about the natural relationship between seals and cod. Twenty-first century science, including DFO Science, knows better.

MYTH 1: Cod stocks are failing to rebuild today because there are too many cod predators in Canadian waters.
MYTH 2: If seal numbers could be lowered in Atlantic Canada, then “it stands to reason” that the numbers of cod would naturally increase. 
MYTH 3Although seals did not demolish the cod stocks (it is generally accepted that human “overfishing” was the primary cause of the collapse), seals have now unfortunately grown “out of balance” with the relatively small number of cod that are left.
MYTH 4: Predators inflict damage and threaten to destroy their prey.  
MYTH 5: DFO Science supports seal culling as a prudent measure to help rebuild cod stocks.  
MYTH 6: The seal hunt does no damage to any other marine species, because only seals are killed. 
MYTH 7: Seal populations are robust and resilient and are capable of withstanding intense commercial exploitation. They will bounce back, because they have done so before.

MYTH 1: Cod stocks are failing to rebuild today because there are too many cod predators in Canadian waters.

It is argued by the fishing industry that cod are failing to rebuild their numbers because too many fish are being eaten by an overgrown population of natural predators (specifically, seals).

FACT: There are now fewer cod predators in Canadian waters than at any other time in recorded history (1).

”…there are currently very few large fish – a situation likely to have never been witnessed in the past.” 

- DFO, 2003

Predator pressure on cod stocks is at an historic low, despite a recent increase in the numbers of some species of seals. The increase in seal numbers has been massively outweighed by a huge decline in the number of other predators capable of eating small fish (as seals do), which has occurred with the recent disappearance of virtually all large fish (big cod, big halibut, sharks, etc.) (1,2). DFO scientists have even noted “insufficient predation” among the factors now having adverse impacts on the health of fish stocks (2). Natural predator “coverage” of the undersea world now appears to be at a dangerously low level. This is dangerous because predator/scavengers are vital elements that work to maintain the “cleanliness” and health of the ocean ecosystem. Without predator/scavengers, the danger rises that “rot” might set in and work to deaden the system.

MYTH 2: If seal numbers could be lowered in Atlantic Canada, then “it stands to reason” that the numbers of cod would naturally increase.     

FACT: Cod numbers in Atlantic Canadian waters are now severely constrained by adverse environmental conditions, and removing seals will in no way lessen these contraints.  

The environmental factors limiting cod growth include a shortage of food (3,4), a declining availability of oxygen in some areas (4), and a lowered resistance of cod to stressors such as cold water (1,4). If these environmental conditions should change in their favour, the population of Atlantic cod would predictably increase, because cod is a naturally robust, persistent species. Under more favourable environmental conditions, fish like cod, that mature in a few years and then produce millions of eggs annually, can swell their ranks quite rapidly. On the other hand, if the environment is stacked too heavily against the survival of cod, these fish will inevitably die off. Unfortunately, at present, adverse marine environmental changes in Canadian waters include ominous plankton shifts, with a significant loss of the small animal plankton (zooplankton) that ultimately feed fish. Part of the role of natural predators, including seals, is to subtly rebuild zooplankton numbers and to thereby work “for” and not “against” the future healthy growth of cod. This makes the intentional elimination of seals or other fish-predators especially risky actions today. Because natural predators crop fish numbers down to match what their environment can currently support, while stimulating new growth of plankton (food) and helping maintain the oxygen content of the water, deliberate predator removal must be contraindicated when a prey species is suffering from adverse environmental conditions, such as is seen with Canadian cod. In today’s marine environmental reality, with weakened plankton, lowered oxygen, and stunted, unhealthy fish, it “stands to reason” that killing more seals will ultimately worsen the odds of recovery for the cod stock. 

DFO scientists have recently described the cumulative impact of the massive removal of large predatory fish from the ocean by commercial fishermen as a factor that has contributed to the generalized starvation of cod and other bottom fish in Atlantic Canadian waters today (3). This is a radical new scientific insight, and one that has serious implications for the future of the fishing industry. This also provides a scientific rationale for ending the seal hunt.

MYTH 3:  Although seals did not demolish the cod stocks (it is generally accepted that human “overfishing” was the primary cause of the collapse), seals have now unfortunately grown “out of balance” with the relatively small number of cod that are left (5).

"The trouble with the world is not that people know so little, but that they know so many things that ain't so."

- Mark Twain

It is argued on this basis that seals should have their numbers reduced to restore a more “normal” seal:fish ratio in the sea, and that, while seals must suffer now for the mistakes of the fishing industry, it should be remembered that people and their livelihoods are more important than the lives of seals.

FACT:  Seals, especially if they exist in increased numbers, actually have the potential to assist in the recovery of the cod stocks today, because all natural predators affect environmental conditions to the benefit of fish. For this reason, seals should now be protected. 

Seals and other natural predators positively affect ecosystem processes, including nutrient cycling, to increase “resource availability” to their prey fish (6). And low “resource availability” is the major problem limiting the growth of cod today. A subtler, less immediately obvious facet of the seal-fish relationship than the killing and eating of prey fish by seals, however this payback scheme between seals and fish is the secret of their long-successful healthy co-existence. In comparison to seals, the fishing industry is young and inept, because humans have not found a way to positively integrate their feeding and excretory habits with the lives of fish, a feat accomplished by seals 25 million years ago. 

It is a positive sign, of residual resilience in the weakened marine animal web, that seal numbers have made gains in recent years, even as prey fish and large predatory fish have both declined. But it must be emphasized that there is absolutely no reason to fear that there are now “too many seals.” Essentially, seals are now making partial compensation for the massive loss of the other large fish predators, and for the resulting negative impact of that loss on the ecosystem. If the underwater domain is not patrolled by enough large predators, who promptly eat exhausted fish as they succumb to environmentally-induced mortality, then dangerous microscopic organisms (rot) will multiply and will further degrade the habitat for fish (and ultimately, for seals too.) Future ocean health must not be sacrificed for short-term financial incentives. Therefore, the lives of seals at this time are worth more than the economic benefit to the commercial sealers. 

Trust the seals, fear the microbes.

MYTH 4: Predators inflict damage and threaten to destroy their prey. 

This is a fundamental human misperception, perhaps based on a subconscious natural fear of animals possessing teeth large enough to consume us. A disinformation campaign has worked for many years to raise a false alarm in the public mind about seals damaging fish stocks because they are “predators.”

FACT: Predators play an important positive role in maintaining ecosystem health.

Robust and healthy marine animal life (as existed for millennia in Atlantic Canada) is largely a promiscuous swarming web of predatory carnivores of all sizes. Although at first glance, savage death seems to run rampant through such a sea, the true nature and the ultimate result of this mass unrestrained carnivorous behaviour is not destruction, but is extremely pro-life. A paradox, perhaps, to the average human imagination, but this is true nevertheless. The actions of ocean predators, and the number of these predators, does not serve to damage or weaken the living animal web in any way, but instead they work to naturally strengthen and vitalize it. Highly evolved fish-dependent predators like seals present absolutely no threat to the continued existence of their prey fish, in part because their own future relies wholly on the future of fish. Seals will not survive without fish, and these marine mammals evolved only after fish were an established presence in the sea. The natural ecology of seals is therefore inherently, strongly pro-fish.

In contrast, there are other marine organisms that now increasingly “threaten” and destroy fish, specifically dangerous primitive microbes that existed in the sea for eons before the evolution of fish. These tiny killers do not depend on fish for their future survival. Therefore, if the current resurgence of bacteria in the ocean expands to the point where fish are eliminated, and microbes dominate the sea again, then the killers of the fish will suffer no particular setback. These species are therefore infinitely more “dangerous” than seals. Uncontrolled growth of bacteria in the sea, such as the microbes that cause dead flesh to “rot,” presents a genuine “threat” to the survival of fish in today’s degraded ocean environment. Ecologically, seals are the antithesis of bacteria.

Seals take advantage of cod weakened or killed by adverse environmental conditions, and this is fine. Better that fish be consumed by seals, than by microbes. Seals and other natural predators selectively kill the weakest and least viable fish in the cod stock. Natural predators, especially the air-breathing seals, can patrol the periphery of a low-oxygen “dead zone,” for example, and selectively remove the weakened and dying individual fish. Fishermen cannot do this, yet we have long vainly assumed that we can simply “replace” natural predators with human fisheries.

No apology needs be offered for the fact that seals eat cod, nor for the tonnage of cod flesh swallowed by seals, whatever that may be. Such numbers are irrelevant to the calculation of the ultimate value of seals and other natural predators in the ocean. When the environment is degraded and less naturally supportive of fish, individual fish simply cannot grow to large sizes as their kind did previously in the same area. Cod and other fish now die off before they can reach the sizes previously attained by their kind, and when these fish deaths occur it is very important that their environment contains natural predators that can eat them. There is a great life-enhancing value in the predatory/scavenger service provided by seals versus the alternate breakdown service provided by bacteria. People who today seek to avert what they perceive as an “explosive overgrowth” of seals in the ocean should ask themselves if they would prefer to see an “explosive overgrowth” of bacteria instead. Because that is exactly where conditions in the ocean are now heading (4, 6, 7), and blindly forging ahead with the seal cull will only serve to hasten this end 

Trust the seals, fear the microbes.

MYTH 5: DFO Science supports seal culling as a prudent measure to help rebuild cod stocks.

FACT: DFO scientists have not concluded that seal culling can help rebuild cod stocks, in fact they have published warnings against the removal of natural marine predators because this could trigger unpredictable negative consequences throughout the ecosystem (8,9).

Calculating the amount of prey fish eaten by seals is not the same thing as demonstrating a negative impact of seals upon fish stocks, although many people (including some scientists) seem to have made this incorrect simplistic assumption. For a while, DFO entertained the “predator pit” hypothesis regarding seals and cod, but this idea has now given way as the weight of evidence points toward environmental conditions being fundamentally unsupportive of cod as they were in the past. DFO Science knows enough today to realize that the seal cull is ecologically irresponsible (as is the associated mass disposal of rotting harp seal corpses in the Gulf of St. Lawrence). The seal cull in Canada is condoned and continues in 2005 for purely political reasons – because it is what the fishing industry demands. However, on paper, DFO is formally committed to finer modern “ocean stewardship” ideals, to the concepts of “ecosystem-based fisheries management” and the “precautionary approach” (9, 10). Hence, a serious conflict now exists inside DFO between the current level of scientific enlightenment and the crude “management” actions that are still taken, although this conflict is still largely hidden from the public under platitudes about “sustainable harvesting of marine resources.”

MYTH 6: The seal hunt does no damage to any other marine species, because only seals are killed.

FACT: The seal cull threatens to worsen the currently degraded state of the ecosystem in which all marine species live.

Living seals are natural catalysts that work to enhance the general health and survival of all larger, more active forms of sea life, including fish, while uneaten dead seals – especially if their corpses fall into oxygen-poor bottom waters, as exist in the Gulf of St. Lawrence – are catalysts for death, and for the a potential runaway dominance of bacteria and rot. Adding a catalyst, or removing one from the system, causes significant effects that cannot necessarily be calculated based on the weight of the catalyst alone. Ocean ecosystem modelers, including scientists working for DFO, have not yet fully realized this basic truth about seals, fish, bacteria, and all else in the sea…and this important basic knowledge gap results in a great deal of the continued “bafflement” of fisheries scientists today, and in their general inability to offer a coherent explanation for today’s broad-scale changes in ocean life.

Old thought patterns – especially when tied to money – die hard.

MYTH 7: Seal populations are robust and resilient and are capable of withstanding intense commercial exploitation. They will bounce back, because they have done so before.

FACT: Not necessarily true, that is exactly what DFO and the fishing industry wrongly assumed about the cod. 

The truth is that warning signs of stress are now appearing in Canadian seals too: diet shifts, range shifts, lowered physical condition of seals…in short, the same biological signals are now appearing in seals that appeared in cod in the early 1990’s before their sudden population crash. Any honest “precautionary approach” to “marine ecosystem management” in Canada in 2005 must include the abolishment of all commercial seal hunting.

Copyright: Grey Seal Conservation Society (GSCS), 2005
(by Debbie MacKenzie, email: Codmother@bellaliant.net )

See also:
"Something is Rotten in the Gulf of St. Lawrence" (more on the hypoxia problem)
"Something (else) is rotten in the Gulf of St. Lawrence" (a related hypocrisy)



  1. DFO, 2003. State of the Eastern Scotian Shelf Ecosystem. DFO Ecosystem Status Report 2003/004.  http://www.dfo-mpo.gc.ca/csas/csas/status/2003/ESR2003_004_E.pdf

  2. Bundy, A. 2004. Mass balance models of the eastern Scotian Shelf before and after the cod collapse and other ecosystem changes. Can. Tech. Rep. Fish. Aquat. Sci. 2520. http://www.osl.gc.ca/cdeena/pdf/esstechreport-2004.pdf

  3. Choi, Jae S. et al, 2004. Transition to an alternate state in a continental shelf ecosystem. Can. J. Fish. Aquat. Sci. 61: 505-510.

  4. Dutil, J.D. et al. 2003. Cod stocks rebuilding and fish bioenergetics: low productivity hypothesis. DFO CSAS Research Document 2003/060  http://www.dfo-mpo.gc.ca/csas/csas/English/Research_Years/2003/2003_060_E.htm

  5. Rice, J. 2002. Changes to the Large Marine Ecosystem of the Newfoundland-Labrador Shelf. (In Sherman and Skjoldal, 2002) 

  6. N. J. Bax. 1998. The significance and prediction of predation in marine fisheries. ICES Journal of Marine Science, 55: 997 – 1030.

  7. Clayton, Mark. 2004. ‘Dead zones’ threaten fisheries. http://www.csmonitor.com/2004/0527/p13s01-sten.html

  8. Swain, D. P. and A. F. Sinclair. 2000. Pelagic fishes and the cod recruitment dilemma in the Northwest Atlantic. CJFAS 57: 1321-1325.

  9. DFO, 2004. Habitat Status Report on Ecosystem Objectives. DFO Can. Sci. Advis. Sec. Habitat Status Report 2004/001.  http://www.dfo-mpo.gc.ca/csas/csas/status/2004/HSR2004_001_E.pdf

  10. Pikitch, E K et al. 2004. Ecosystem-Based Fishery Management. Science 305: 346-347 (July 16, 2004)

Excerpts from numbered references above, with notes:

1. DFO, 2003. State of the Eastern Scotian Shelf Ecosystem. DFO Ecosystem Status Report 2003/004. 

”…there are currently very few large fish – a situation likely to have never been witnessed in the past.”

“Condition and growth of several groundfish species has remained low during the past decade contrary to expectations for improvement.”

“It is not yet possible to predict how long the current situation will persist and whether or not the system will return to its previous groundfish-dominated state.”

 “Although only a few of the several traditional groundfish species have been routinely aged, the available information reveals striking and unexpected reductions in growth.” (cod, haddock, Pollock, silver hake) 

“…the trend of reduced size has occurred, despite current low population levels, suggesting that a fundamental, population dynamic process (compensatory growth) is not working among these species.”

“Concerns have been expressed repeatedly about the impact of the expanding grey seal population on the recovery of cod. Sand lance and other non-commercial species are the most common prey in the diet with cod contributing a small fraction of the fish consumed. Because the cod population is so low, it is assumed that any additional source of mortality may be detrimental to the remaining stock. 

Estimates of grey seal consumption are calculated from a population model, which incorporates metabolic requirements of individual seals. Current population size and diet of grey seals are not available. But if the rate of growth has continued at past levels, then the population could have doubled since the last survey in 1997 to near 225,000 in 2002. Based on this extrapolation and recent evidence from fatty acids that cod may account for only about 1% of the diet in recent years, the estimated consumption of cod by grey seals is in the order of 3,000 t, compared to a total cod population biomass of 8,800 t. Recent satellite tracking of adult grey seals indicates that a fraction of the Sable Island population forages in areas beyond the boundaries of the Eastern Scotian Shelf ecosystem. Therefore, the consumption of cod by grey seals in this ecosystem may be less than that currently estimated. The impact of grey seal predation on the dynamics of cod is an active area of research and there are continued concerns on the role of seal predation on cod recovery.”

(DM: DFO has not yet reached the stage of considering how the massive removal of large animal life from the sea naturally tips the balance of power to dangerous levels of bacterial growth.)

2. Bundy, A. 2004. Mass balance models of the eastern Scotian Shelf before and after the cod collapse and other ecosystem changes. Can. Tech. Rep. Fish. Aquat. Sci. 2520.

Grey seals “have become the main predator of fish” on the ESS. (DM: This should gives an important reason to protect these seals – and not to authorize a new grey seal cull in Nova Scotia, as DFO did in 2004.)

The size of the increase in the biomass (tons/sq. km) of grey seals on the ESS is about 1/20th of the magnitude of the decrease in the biomass of large fish between early 1980s and late 1990s. (DM: The increase in seals does not come close to making up for the loss of large fish.)

p. 106 “We know least about the part of the ecosystem that is its bedrock” (the lower trophic levels, bacteria, plankton)

 “…Note also that even with the large increase in grey seal abundance on the eastern Scotian Shelf, there is not enough consumption of these prey species to account for all their production.”

p. 101 “…almost all of the (recent) mortality of large cod is inexplicable…Thus, for large cod, the total estimated mortality is twice the production, so unless mortality is reduced, this population will continue to decline. On top of this, we do not know what is causing the mortality.

The question of high mortality estimates, particularly in large cod, is problematic and is common to many Canadian East Coast cod stocks, with the exception of NAFO Div. 4X cod. There have been DFO projects, workshops and papers written on this problem, but there is, as yet, no resolution (e.g. Chouinard et al. 2002, Powles 2002, Smedbol et al. 2002, Dutil et al. 2003). It remains at this stage to indicate that modelling the ecosystem with Ecopath has not been able to shed further light on this problem.”

p. 108 “In the 1980-1985, cod was the main predator, whereas in the 1995-2000, grey seals and silver hake are the main predators. Total consumption by grey seals, silver hake and cod is less in 1995-2000 than it is in 1980-1985. There is thus less consumption by top predators in 1995-2000.

There are large unknown mortality estimates for several groups. The ecosystem has greatly changed and there are few top predators in 1995-2000. Unknown mortality may be due to disease or senescence because there is not sufficient predation.”

3. Choi, Jae S et al, 2004. Transition to an alternate state in a continental shelf ecosystem. Can. J. Fish. Aquat. Sci. 61: 505-510.

“…coherent, community-level reductions in body size, biomass, and physiological condition have occurred in the resident demersal fish species…suggesting a progressive decline in the nature and extent of the energy flow through the benthic system…” (DM: Translation: all bottom fish are now stunted and severely limited by a lack of food.)

(Regarding the Scotian Shelf cod collapse) “The spectacular nature of this collapse and the scientific and public attention that it received has obscured the much more profound coincident ecological collapse of an entire complex of previously abundant demersal fishes, many of which were subjected to only modest exploitation.”

 “Throughout the 1970s and 1980s, large individuals dominated the northeastern half of the shelf. Individuals >8 kg were found in >75% of the area sampled and by the 1990s had declined to 40%. Currently large fish occur on only 10% of the area surveyed and are restricted to the northeastern edge of the shelf. Numerically, the magnitude of this change was profound. Relative to the 1970s, there are currently 95% fewer fish >8 kg and fish of intermediate size (1-8 kg) are 60% lower in abundance. Conversely, small fish (<0.1 kg and 0.1 – 1 kg) have increased by 375% and 100% respectively. These changes in body size result from variations in species composition, size-specific mortality, and reduced growth rates (DFO 2003).”

Between 1970s and 2000s, “a sustained reduction in physiological condition” occurred.

“Collectively, these patterns reveal progressive erosion in the bioenergetic “well-being” of the resident groundfish community.”

Conclusion…”…changes seen in the groundfish community of the eastern Scotian Shelf are indicative of a severely perturbed system with reduced functional diversity…This makes the prediction of the conditions required for stock recovery and their associated time scales difficult and highly uncertain. The complexity of the interacting factors involved in the dramatic restructuring of the Scotian Shelf ecosystem highlights the problems inherent in attempting to manage individual species within the framework of a complex and dynamic ecosystem.”

(DM: These authors, DFO scientists, describe profound system-wide changes that have unexpectedly occurred on the Scotian Shelf, and that have included a massive loss of large fish. They certainly do not suggest that a seal cull will help reverse the negative changes, and in fact they imply the opposite in their suggestion that small pelagic fish (seal food) has become overgrown to the detriment of the bottom fish, including cod.)

4. Dutil, J.D. et al. 2003. Cod stocks rebuilding and fish bioenergetics: low productivity hypothesis. DFO CSAS Research Document 2003/060

5. Rice, J. 2002. Changes to the Large Marine Ecosystem of the Newfoundland-Labrador Shelf. (In Sherman and Skjoldal, 2002)  Jake Rice is a senior DFO scientist.

p. 92 “…attention is turning to seal predation as a major cause of the elevated mortality. With annual harvests well below replacement production, the harp seal population has reached the highest abundance in the time series (which began in 1972). Moreover, the herd is staying in the Newfoundland Shelf large marine ecosystem much longer than historically. Although consumption estimates are only available for cod, and numerous uncertainties remain, seals are estimated to be consuming at least 80% of the production of cod in 2J3KL in recent years, and represent a source of significant mortality to cod up to at least age 5 (DFO 1999).” (DM: Rice, along with other DFO scientists, does not distinguish between otherwise viable and otherwise non-viable cod that are eaten by seals. And this represents a major flaw in this analytical approach.)

Conclusion, p. 95  “The slowness of the system to return towards an historic “typical” configuration when stresses from both fishing and the physical environment are largely eliminated raises new and deeply troubling questions about managing ecosystem trajectories.” (DM: “Deeply troubling questions” indeed…)

p. 55 “The ability to explain the dynamics of the larger marine ecosystem of the Newfoundland shelf is severely limited by the lack of time series data on living components of the system except for a few species of fishes and seals.”

p. 56 “With regard to plankton dynamics…although it would be highly desirable to incorporate dynamics of the primary producers and small zooplankton into a grand synthesis, the data simply do not allow that step to be taken.”

6. N. J. Bax. 1998. The significance and prediction of predation in marine fisheries. ICES Journal of Marine Science, 55: 997 – 1030.

(DM: This seems to be a good, comprehensive review article. Bax, however, in common with other writers of this type of article, consistently uses the phrase “losses to predation” when describing the direct effect of predators’ eating their prey. Not acknowledged by this author, or by others in my experience, is the fact that some of the flesh consumed by “predators” was already dead or dying, and that these fish having been eaten by a predator does not constitute a “loss” to their kind as much as a “loss” to alternate forms of decomposition (such as bacterial) which might occur in the absence of the predator/scavenger. )

Bax acknowledges the current inability of science to make accurate predictions of the end results on fish stocks of culling their predators.

“Although short-term management objectives may be achieved in ignorance of the system to which they apply, longer-term, strategic management that has as its objective maximizing harvest under a set of constraints, requires and understanding of the interactions of species and of fisheries within the context of their physical environment and habitat.”

“Change is direct when a predator kills a prey, and indirect in a multitude of ways, including predation on shared prey resources, effects involving intermediate predators, and predation influencing prey behaviour and resource availability.

A typical negative assessment of the impact of the “harvesting” of fish by marine mammals, rampant in fisheries science literature, is included here:

“…the amount of commercially important fish eaten by marine mammals is similar to or exceeds that taken by the commercial fishery in at least five areas (South Georgia, Kerguelen Islands, Southern Africa, North-west Atlantic, Bering Sea).”

And another classic theme: a general resentment of fish eaten by seabirds:

“Northern gannets in Newfoundland waters, which harvest the same sizes and species of pelagic prey as the commercial fishery in the area, often harvest more mackerel and squid than the commercial fishery lands.”

Also described by Bax are “losses” to cannibalism – a rather awkward concept, if cod is taken and integrated into larger cod – how is this a “loss” to the species?  “Predation by fish appears to range from 2 to 35 times the loss to commercial fisheries.” (DM: There seems to have been a deliberate plan by fisheries managers in the past to deliberately remove the larger fish for just this reason – it was thought to be inefficient to have big fish consuming the smaller, faster-growing population members that could be more profitably taken by fisheries. So, a tendency to resent the predatory activities of fish has been a part of classic fisheries science and management. Belatedly, we have realized this was a serious mistake.)

The fact that predators also readily scavenge dead or injured fish is acknowledged in the context of fishery discards, but not as a part of the natural consumption of these types of fish by these types of predators.

“The occurrence of fish in the diets of seabirds does not necessarily imply predation on live fish. Where commercial fisheries operate, a large proportion of seabirds’ diet can come from fish discarded from the boats.”

(DM: Yet, the occurrence of fish in the diets of seals seems always to imply their predation on otherwise viable fish, even when they are taking larger individuals than they ate in the past – which is really an indicator of the debilitated condition of larger fish today, as they are forced down by adverse environmental conditions. )

In this article, a table shows the “annual biomass of fish lost to fish predators and the fishery…”

(DM: Without the predators, populations of fish would naturally have a certain lost annual biomass in fish that died. Predators selectively consume this portion of the fish population, while fisheries are incapable of directly targeting exhausted fish in this manner. The assumption runs throughout this article that the ecosystem effects of “fish predators” and the “fishery” can be compared directly, but they cannot.)

“The effects of predation are intertwined with those of food availability: starvation leads to an increased susceptibility to predation.” (DM: DFO should be acknowledging this fact today, along with the other risk of starvation: death.)

8. Swain, D. P. and A. F. Sinclair. 2000. Pelagic fishes and the cod recruitment dilemma in the Northwest Atlantic. CJFAS 57: 1321-1325.

Abstract: “…the recent suggestion that the success of large predatory fishes may depend on “cultivation” effects in which the adults crop down forage fishes that are predators or competitors of their young. Our result also point to the possibility of a triangular food web involving cod, seals, and pelagic fishes, making it difficult to predict the effect of a proposed cull of seals on the recovery of cod.”

Discussed “implications of such an effect for management action that has been proposed to accelerate the recovery of cod in the Northwest Atlantic, namely a cull of seal populations in this area.”

(DM: The suggestion made here is that seals may provide an important protective service to young cod in the absence of a strong presence of older cod – a warning against thinking that a “seal cull” will result in more cod survival.)

“Our results could also have implications for the recommendation that seal herds off Atlantic Canada should be reduced to promote cod stock recovery (FRCC 1999). It has been suggested that large increases in seal abundance have resulted in increased predation on cod, thus delaying stock recovery. However, pelagic fishes like herring appear to be an important component of seal diets (e.g. Bowen et al. 1993). These results point to the possibility of a triangular food web involving cod, seals, and pelagic fishes. Manipulation of such food webs can lead to unexpected results (Bax 1998). Seals may have a direct negative effect on cod recruitment through predation on prerecruit cod. They also may have an indirect positive effect through predation on pelagic fishes, possible predators of early life history stages of cod, so that reductions in the seal herds may not lead to improved recruitment of cod. Bax (1998) emphasizes the danger of concentrating only on direct predation interactions when there are indirect interactions with the potential to reverse the direct effects. Our results suggest that a better understanding of the interactions between cod, seals, and pelagic fishes is needed before it will be possible to predict the effect of a seal cull on cod abundance.”

(DM: This article was written by two DFO scientists.)

9. DFO, 2004. Habitat Status Report on Ecosystem Objectives. DFO Can. Sci. Advis. Sec. Habitat Status Report 2004/001.

Intro: “E. To maintain trophic structure so that individual species/stages can play their historical role in the food web.”

(DM: But we need to acknowledge the shifting roles of seals and others…for instance, which creatures are now playing the “historical role” of the large fish? The seals?)

H. To conserve water column properties
I. To conserve water quality
J. To conserve biota quality.

Background – “Ecosystem Objectives” are starting point for setting “operational ecosystem objectives.”

Two types of ecosystem objectives: (1) to prevent harm (2) to achieve desired states

“When suites of ecological and social, cultural, and economic objectives are being set, it is essential that they be reviewed as a package, to ensure that they are mutually inter-compatible. In particular, activities necessary to achieve all the desired social and economic uses of marine ecosystems may not be possible without violating ecosystem objectives set to protect ecosystem components from harm. In such cases, it is necessary to revise the social and economic objectives, to ensure that the ecological conservation-based objectives are not compromised.

Suites of ecosystem objectives have to consider together, once they have been set, to ensure that as a group they cover important parts of the marine ecosystem adequately. They also have to be evaluated relative to expected major threats, to ensure that the suite includes operational objectives for ecosystem properties expected to be exposed and sensitive to them. It is also necessary to consider in advance how the operational objectives will be used to assist in management of cumulative impacts as well as activity-specific impacts.”

“Generally, those setting EOs and their operational components (e.g. reference points), should consider data and information covering as wide a time period as possible, and encompass periods when, with current knowledge, the ecosystem would be considered healthy.

We lack time series of data for many ecosystem properties for which EOs may need to be set. Even where data series exist, most come from recent decades at best, and from times when human activities had already altered the ecosystem in important ways. Therefore our time series may limit artificially what we perceive are the natural state or bounds of natural variation. Given the repeated occurrence of the phrase “within bounds of natural variability” in the conceptual objectives and components, this limitation may have some uncomfortable implications for making the conceptual objectives operational.

Those managing human activities in marine ecosystems have an obligation to try to evaluate management actions intended to achieve individual ecosystem objectives with regard to the impacts of those actions on the other ecosystem properties addressed in these Guidelines…”

“When setting Ecosystem Objectives intended to address perceived problems, it is important to consider root causes, and not just symptoms. Work to improve understanding of those root causes should be a priority.”

(DM: The root cause of the failed rebuilding of the groundfish is most definitely NOT seals.)

** “The consequences of management manipulations of trophic systems are highly unpredictable. Therefore, only under conditions of exceptionally good understanding would there be a scientific basis for forming Ecosystem Objectives which might lead to planned major reductions of predators with the intent of producing specific benefits to populations lower in the food web.”

“Because the consequences of management manipulations of trophic systems are highly unpredictable, Ecosystem Objectives should not knowingly guide management to allow actions that substantially alter the ratio of different trophic levels in the food web or size classes in the seize composition of the web.”

(DM: So, today, when the predator “trophic level” has already been “substantially altered” (i.e. decimated), no other organisms should now be removed from this level – in other words, the seal cull is contraindicated.)

“These guidelines should be applied on spatial scales large enough that population dynamics processes are likely to dominate over extrinsic factors such as migration. (That is, Ecosystem Objectives to maintain particular trophic structures on very local scales are likely to be impossible to achieve, because the presence and abundance of many of the species may be determined by factors acting on much larger spatial scales.)”

(DM: In other words, seal exclusion zones should not be proposed.)

“Food webs are complex and even in knowledge-rich systems ability to predict specific consequences of management actions or environmental factors influencing the trophic structure will be limited. However, our knowledge of trophic relationships is very weak for most marine systems, and better information would improve our understanding of at least general consequences of perturbations to food webs.”

(DM: Therefore, we do not have the “exceptionally good understanding” required for setting any objective involving “planned major reductions of predators…”)

“Moreover, resilience of ecosystems provides another justification for ensuring that management is aware of and responsive to the ecosystem stresses caused by natural and anthropogenic factors. To protect ecosystem resilience, the cumulative effects of both natural and human stresses on ecosystems need to be recognized and accommodated in management.”

(DM: Scientists should therefore consider the oxygen consequences of the current harp seal cull/seal corpse disposal activity, especially in the hypoxic  Gulf of St. Lawrence. Dead seals are too likely to decompose, aggravating bottom water hypoxia…)

“…habitat is defined broadly to include the physical and chemical features required by living organisms to carry out their life process.”

“Where biological functions of structural habitat features are known, those should be given prominence in setting Ecosystem Objectives.”

(DM: Again, all the right phrases are in included in this article to lead to the scientific prohibition of the dumping of seals in the oxygen-stressed bottom waters of the Gulf of St. Lawrence.)

“Knowledge of the causes and robustness of the structural and functional properties of communities is particularly limited, which makes it hard to set operational Ecosystem Objectives for those properties directly. However, there could be some role in management for Ecosystem Objectives intended to prevent major changes in the relative abundance or distribution of species and habitat features in the community, with the expectation that preventing such changes at least reduce the risk of harm to structural and functional community properties. In these cases, however, attention should be given to ensuring that the Ecosystem Objectives can be clearly linked to management actions with known consequences, so the populations can be maintained with high certainty.”

(DM: All that is needed is for DFO to realize that seals are some of the “causes” of “robust functional properties of communities”…)

** “If Ecosystem Objectives are to be set for intentionally reducing a species’ abundance significantly, the evidence of serious and widespread harm needs to be very strong, such as with harmful algal blooms. In such cases there also needs to be a good understanding of the consequence of the management actions taken to achieve the EO.”

(DM: Seals are in no way equivalent to harmful algae blooms! We can assume that a modern large, fish-dependent, and later-evolving organism such as the seal appeared as part of a positive, fish-sustaining ecosystem. Harmful algal blooms and bacteria, on the other hand, can and have already lived during eons when the sea contained no fish, or seals. They will do so again.)

“There is very limited understanding of how ecosystem properties and management consequences scale up and down. This area needs more study, and management need to be cautious in making assumptions about consequences and interactions of management actions which pursue Ecosystem Objectives on several scales.”

“…uncertainty is amplified by a number of factors. These include…Limited knowledge of the contributions of the various species, habitat features, and their linkages and relationships to the higher-order ecosystem properties like stability, diversity, resilience, etc….Limited understanding of second order (indirect) impacts of manipulating individual ecosystem components.”

(DM: Again, this does not compare well with the requirement for “exceptionally good understanding” before a seal cull can be justified as a management plan.)

“…the Guidelines reflect consensus of substantial expert knowledge, and there is some confidence that their application will at least improve performance relative to practice without any Guidelines.”

(DM: Fine, a great many of the right words have recently been written by DFO’s ecosystem scientists - now let’s see some honest, gutsy translation of this new thinking into practical resource management decisions …)

10. Pikitch, E K et al. 2004. Ecosystem-Based Fishery Management. Science 305: 346-347 (July 16, 2004)

“Ecosystem-based fishery management (EBFM) is a new direction for fishery management, essentially reversing the order of management priorities to start with the ecosystem rather than the target species.

The overall objective of EBFM is to sustain healthy marine ecosystems and the fisheries they support. In particular, EBFM should (i) avoid degradation of ecosystems, as measured by indicators of environmental quality and system status; (ii) minimize the risk of irreversible change to natural assemblages of species and ecosystems processes, (iii) obtain and maintain long-term socio-economic benefits without compromising the ecosystem; and (iv) generate knowledge of ecosystem processes sufficient to understand the likely consequences of human actions. Where knowledge is insufficient, robust and precautionary fishery management measures that favour the ecosystem should be adopted.”

Goals of EBFM include “protect ecosystem resilience and avoid irreversible changes.”

“The impacts of fisheries on endangered and protected species, including ecological processes that are essential for their recovery, should be managed through an EBFM approach.” …EBFM also intended to “manage indirect effects” on endangered species or processes.

“…the judicious use of a precautionary approach. This means erring on the side of caution in setting management targets and limits when information is sparse or uncertain. Greater uncertainty would be associated with more stringent management measures…Ideally, EBFM would shift the burden of proof so that fishing would not take place unless it could be shown not to harm key components of the ecosystem.”

“New analytical models and management tools will be needed as well. Multispecies and eco-trophic models must be refined and expanded to better account for system-level uncertainties, to derive system-level reference points, and to evaluate the ecosystem-level consequences of proposed EBFM actions.”

(DM: This context can be interpreted for sealing too, obviously…)

“Because EBFM emphasizes habitat and ecosystem function in the context of fluctuation, advanced models for EBFM should incorporate spatial structure and environmental processes.

EBFM may require evolution from suites of single-species fishery management plans to integrated ecosystem-based fishery management plans (EBFMP). In an EBFMP, the impact of a management action would be assessed with respect to the ecosystem as well as individual species. It is entirely possible that a fishery could be considered overfished within the ecosystem plan (ecosystem overfishing) when it is not over fished in a single-species context.”

“Rebuilding ecosystems from their degraded state, in turn, might inflict short-term economic hardship on fishers. The transition to EBFM might thus involve compensating fishers and providing incentives to other stakeholders to support EBFM as a long-term strategy.”

“EBFM should move forward now despite current uncertainties about ecosystems and their responses to human actions because the potential benefits of implementation are as large as or greater than the potential risks of inaction.”

(DM: This eminently sensible consensus statement and visionary piece was authored by 17 marine scientists from the United States, Europe and Australia, and it was published in the world’s premiere science magazine. No Canadian scientific voice chimed in on this, unfortunately.)


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