The Canadian Department of Fisheries and Oceans held a "Seal Forum" in St. John's, Newfoundland, on November 7-8, 2005, to elicit advice from "stakeholders" regarding the formation of a new multi-year "Atlantic Seal Management Plan." I attended the forum representing the Grey Seal Conservation Society (GSCS). Below are my comments submitted to DFO following the forum for inclusion in the seal forum report. Prior to the seal forum, the same concerns were communicated to Geoff Regan, Minister of Fisheries and Oceans, Canada, in a letter dated October 20, 2005. When a response is received from DFO or Mr. Regan on this matter, I will add it to this website. - Debbie MacKenzie, November 21, 2005
November 17, 2005
To: Brianne Rossi
Comments on DFO 2005 Seal Forum from the Grey Seal Conservation Society (GSCS)
Dear Ms. Rossi,
The Grey Seal Conservation Society (GSCS) appreciates your providing us with the opportunity to participate in the 2005 Seal Forum. DFO made us feel very welcome at this event – thank you. The following are our comments on the matters discussed at the seal forum:
1. GSCS opposes the seal hunt plan
because marine predators overall are severely depleted, and the
ecosystem-stabilizing effect of large predators is thereby being lost.
1. GSCS opposes the seal hunt plan because marine predators overall are severely depleted, and the ecosystem-stabilizing effect of large predators is thereby being lost.
The Grey Seal Conservation Society (GSCS) opposes the proposed commercial seal hunt plan (for harp seals, grey seals and hooded seals) in Atlantic Canada, in favour of the inclusion of all seal species in a moratorium on the commercial take of large marine fish predators. This position is based on concern arising from the recent virtual disappearance of all large predatory ocean fish, and DFO’s obligation to use an “ecosystem based approach” to managing living resources (1,2).
In suggesting TACs for the seal hunt, and in forecasting the hunt’s “sustainability” at the seal forum, DFO has unfortunately relied only on a single species modeling approach, like that considered in the Report of the Eminent Panel on Seal Management (2001). This approach is currently inadequate, however, because it does not constitute “ecosystem based management,” which DFO is now obliged to use under the Oceans Act.
Along with the seal biologists, marine ecologists should have been consulted on the matter of seal hunting, with a view to understanding the context in which seals are living today, how seals relate to the current state of the ecosystem, recent changes, and the importance of maintaining the natural structure of the food web. Dramatic unexpected shifts have recently been observed in the ecological base that supports seals (fish, invertebrates, plankton), yet DFO has inappropriately continued to offer an optimistic, simplistic assumption that seal populations can be projected to thrive and multiply into the future as they did in years past, when seals were supported by a vastly different and more productive food web. Unfortunately, this is the same tunnel-vision management approach that preceded the “unexpected” cod collapse.
The transition from the old style fisheries management to ecosystem-based management is clearly not easy for scientists (3), yet DFO is committed and obliged to figure out how this can be done in practice. Ecologists can help fisheries managers adapt to the new realities and to incorporate new scientific insights in their work, and indeed, DFO ecologists have recently clarified what a modern “ecosystem approach” to fisheries management should look like. DFO’s move toward an “ecosystem-based” management approach involves the identification of measurable, precautionary “ecosystem objectives” (4,5), and then it involves the consideration of these objectives when making fisheries management decisions. It is becoming very clear what must be done, and DFO would do well to make the leap to genuine “ecosystem-based management” of the seal hunt at this time, in part because this hunt is such an anomaly (a hunt on a top predator) in an era when fisheries targets overall are sliding ever lower in the food web (now mainly crustaceans).
A top priority of ecosystem-based management is the maintenance of all “components” and all “functions” that occur naturally in the ecosystem, and it is acknowledged that a considerable overlap of different species can be involved in maintaining a given functional role in the ecosystem. Such species are described as sharing a “trophic level” or a feeding position in the food web.
An objective related to the goal of “maintaining trophic structure” has been identified by DFO as “preserve traditional role of top predators.” (6) Seals function as top predators, but seals are now in the unprecedented situation of being the last remaining major players involved in functioning at their trophic level, in contrast to past circumstances when seals shared the top predator functional role with a great number of large predatory fish of various species. (7, 8)
An extremely worrisome, near-total disappearance of all large predatory fish has occurred in Atlantic Canada, and this has been linked to fishing. To make matters worse, spontaneous rebuilding of these predators is not occurring as expected. Seals are unique in being the only top marine predators that have demonstrated any degree of population resilience in recent years. Despite increases in some Atlantic seal populations, however, the strength of the top predator functional role overall has declined markedly. (7, 8)
Significantly, DFO scientists have recently concluded that the loss of the natural ecological function of large-bodied predators has already triggered an unexpected cascading effect that has induced a “catastrophic” alteration in the food web. (9) The changes induced by massive predator removal are viewed as “catastrophic” because they include a decline in plankton and the generalized starvation of bottom-dwelling fish (9, 10). This new insight gives an urgent reason to ban the take of any more large-bodied predators. DFO’s commitment to “preserve top predators” does not therefore arise only from an aesthetic, sentimental or moral belief of Canadians that we should permit large ocean animals to survive into the future, but it also arises from a scientific recognition that it is dangerous to the health of many other marine species (including prey fish) for the numbers of fish predators in the system to be drastically reduced. Unexpected, counter-intuitive perhaps, but this is where the weight of evidence points nevertheless.
DFO ecologists understand what management measures will be needed to conserve a “trophic level”:
“Regarding trophic structure…it may be necessary to set overall catch limits for aggregates of species based on their trophic level. Once the overall catch is met, all fisheries for species in that aggregate would be halted.” (O’Boyle et al, 2004)
It is widely acknowledged that the “aggregate” of top ocean predators has been reduced to a level below 10% of its historic abundance, (11, 12, 13) and it seems this reduction has already had a significant negative impact on the ecosystem (7, 9, 11). The precautionary approach, “erring on the side of caution” in this situation, should therefore dictate that predator removal now be halted due to the risk of causing further ecosystem-destabilizing effects. Therefore, commercial seal hunting should be stopped at this time. No more top predators should be removed. This is the basis on which the Grey Seal Conservation Society (GSCS) opposes all commercial seal hunting that DFO has suggested be included in the new Atlantic Seal Management Plan.
2. Ecosystem Considerations
In the 2005 Seal Forum Workbook, DFO correctly identified “ecosystem considerations” as an “aspect of the seal hunt needing improvement.” But despite this, and Kevin Stringer’s closing remark to the forum that “There is no question that DFO is moving toward an ecosystem approach”, DFO failed to clearly communicate the meaning of “ecosystem approach” to the forum participants. This point of ongoing misunderstanding seems likely to be related to DFO’s failure to include ecologists or “ecosystem” scientists in consultation on the seal hunt plan and the seal forum.
It became clear during the forum that confusion existed regarding the practical meaning of the phrase “ecosystem-based management.” This was the argument advanced by GSCS, as described above, as the reason not to approve any more commercial catches of seals, yet the exact same phrase was used by members of the fishing industry as an argument in favour of culling seals in a “cod recovery” strategy. The reason for the fishermen’s mistakenly equating “ecosystem based management” with “predator control” can be easily seen: because “seal predation” was the one major topic suggested by DFO under “ecosystem considerations” in the forum workbook (Section 2).
By now, DFO should have explained more of the truth about recent ocean ecosystem changes to the fishermen. Fishermen who participated in recent consultation with DFO scientists regarding “cod recovery” reported that they had not been told that a significant, sustained decline in zooplankton abundance on the Newfoundland shelf has been observed, and that this bodes poorly for the future growth of fish. Nor has it been explained to the fishermen, apparently, that the recently observed trend of poor condition in mature groundfish is something that has long been associated by scientists with an unusually LOW level of predation, rather than with an unusually HIGH level of predation (whether from fishing or from natural predators).
DFO has not done enough to dispel the myth that natural predators are “damaging” fish stocks. While scientists have stated this is not their conclusion, they have done a poor job of convincing the fishing industry on this point, or of reducing the fishermen’s mistrust of seals. In fact, DFO scientists still seem to act to perpetuate the myth of the “danger” presented by seals as they have intensified their efforts to quantify the consumption of fish by seals. The underlying assumption of DFO’s seal research program seems to be a belief that the consumption of fish by seals is inherently harmful to fish stocks.
“Even if the Department was to contemplate a cull to reduce seal predation, the number of seals that would have to be taken to have a significant effect on fish populations would be enormous and would undermine the current seal harvest. For example, under one Eminent Panel scenario based on their bio-economic analysis, there would have to be an additional harvest of either 750,000 seals in a single year, 150,000 additional young seals per year for five years, or a cull of 150,000 adult females to provide about 1,500t of commercially usable fish (not just cod).” (2005 Seal Forum Workbook)
The assumption that removing seals will work to the benefit of their prey fish cannot be justified today in the face of recent evidence that significant predator removal can cause broad-scale ecosystem damage. DFO needs to communicate this fact to the fishermen. Senior DFO scientist, Jake Rice, has cautioned against planning predator culls as “ecosystem objectives”:
“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.” (5)
Ecologists now have a good understanding that while predator removal may or may not result in a brief increase in prey abundance, the practice eventually causes ecosystem deterioration that can ultimately inhibit the production of prey. Ample evidence exists that the massive level of marine predator removal already accomplished by the fishing industry in Atlantic Canada has not worked to the ultimate benefit of the prey fish. The “predator removal” experiment by fishermen has in fact already been carried on for centuries with the broad-scale removal of all large fish, and at this time the fishing industry’s predator removal strategy can be seen to have achieved near-total success. However, natural predator removal plainly does not work to improve fish production – as unexpectedly, it seems to have had the opposite effect.
DFO might help fishermen understand the folly of their proposed final predator-removal strategy to rebuild cod stocks if fishermen were reminded that cod were traditionally the main predators of capelin in Newfoundland, but that the elimination of cod apparently has not worked to the benefit of capelin, because rather than growing larger the capelin stock has unexpectedly become smaller in the absence of its major predator. It is not remotely possible that the current seal population is eating more capelin than cod and other now-absent large fish once consumed on the Newfoundland banks. Much does not add up under the traditionally accepted view of how the ocean works. Hence, as noted in the seal forum workbook, “complexities abound in the seal-predation puzzle”…
3. The “seal-predation puzzle”: What is the full impact of the presence of seals in the sea? Predators? Scavengers? Nutrient-cyclers?…What is the full expected impact of their removal?
The “complexities” in the “seal-predation puzzle” should be urgently addressed by science. In its recent seal research program, DFO has approached the issue only by trying to obtain more accurate estimates of numbers of seals and the amount of fish they eat. To this end, DFO’s seal diet studies have become quite sophisticated. However, researchers have failed to account for a serious shortcoming in this line of study. This is the false assumption that fish flesh eaten by seals always represents otherwise viable fish, fish that might have survived to support a human fishery. It is important to note that in estimating the “impact” of seals, scientists have made no distinction between the roles of “predator” and “scavenger,” although seals perform both these roles when they eat fish. While confusion remains about the desirability of “predator” removal, “scavenger removal” is clearly undesirable because this presents an environmental risk, as dying/dead fish that are not eaten promptly by scavengers may undergo bacterial decomposition (rot) on bottom instead, a process that can degrade water quality.
The ecological demand for scavengers to consume spent adult fish is likely to have increased in Atlantic Canadian waters recently, as the natural life expectancy for virtually all fish species has fallen. This change has been imposed on fish by a limited availability of food in their environment (9), and this is a major determinant of when adult fish become due for recycling by scavengers. The fishing industry can do nothing to replace the important scavenging piece-work service that natural predators perform in the ocean as they selectively consume spent fish.
In the Gulf of St. Lawrence, the exceptionally deep-diving hooded seals may be the only predators/scavengers that can still function effectively today in the Laurentian Trough. The oxygen content of the bottom water in much of this area has recently fallen to levels too low for other consumers, such as predatory fish, to survive. Therefore, it may realistically be that the only air-breathing fish-eaters capable of diving to the bottom in this area, the hooded seals, represent the single natural ecosystem element that can still work to slow the spread of this “dead zone” by eating fish that die there. This illustrates one subtle dynamic by which seals help maintain the health of the ocean environment.
It has often been observed by scientists and fishermen that adult seals may consume tons of fish for each seal pup they produce, but this process has too-simplistically been imagined only as a “loss” inflicted on the fish stocks. Questioning more deeply, it should become of interest to scientists to follow the trail of where the bulk of the fish eaten by seals actually goes. Seal excretions are tightly linked to natural processes involving marine invertebrates, which ultimately lead to a more rapid cycling of fish-derived nutrients into plankton-stimulation than would occur in the absence of seals. This is another subtle, positive impact of seals on ocean health.
In its seal-ecosystem research, DFO should now shift the focus toward taking a comprehensive look at the intertwined ecology of seals, fish and other ocean elements, toward understanding the full “complexities” in the “puzzle.” Before another seal hunt is approved, those who would promote the seal hunt should be required to meet the “burden of proof” that top ocean predators can still be commercially hunted today without risking further detrimental effects to the ecosystem. This is very unlikely to be proven, which provides the reason why a “precautionary” moratorium should be placed on the commercial harvest of seals or any other top ocean predators in the interim.
4. Setting conservation limit reference points, in an ecosystem context.
A logical objective scaling process, similar to DFO’s recent “Objectives Based Fisheries Management” (OBFM) approach to seal hunting, could be used to assess the appropriateness of the seal hunt in an ecosystem context. The major difference would be that the conservation limit reference points would be determined on the basis of conservation requirements for the trophic level, or “aggregate of species,” of which seals make up one part. Either overall abundance estimates of animals occupying the seals’ trophic level, or biomass estimates of all animals in this category, might be used as measurable reference points to trigger conservation actions for the trophic level as a whole. Such an approach would constitute logical, practical “ecosystem-based fisheries management,” and this very approach has recently been suggested by DFO ecologists and others.
If the seal populations were assessed under this “ecosystem” method, then a current “conservation” issue involving these animals (i.e. their trophic level) would immediately become clear, despite relatively high current numbers of seals. The marine top predator trophic level in Atlantic Canada is currently well below 10% of its historic biomass, or its historic abundance, whichever measurement you prefer. If DFO were to set conservation limit reference points on an ecosystem basis, then an “all removals stopped” management strategy would now be implemented for seals.
DFO must make the leap to “ecosystem-based fisheries management,” and the seal hunt may be the best place to start. Incontrovertible evidence supports the conclusion that the seals’ trophic level is currently severely depleted – therefore the decision to conserve seals on “ecosystem” grounds can be made and justified by scientists with no uncertainty at all, whereas the situation might be stickier in other instances.
The rationale given here for halting the harvest of seals in Canada can also be found in various other scientific sources:
“In an ecosystem-based fishery management plan (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 overfished in a single-species context. This can occur when a forage species that serves as a prey resource for marine predators is also the target of a fishery or when overfishing of large predators causes food web shifts.” (Pikitch et al., 2004)
5. Future Consultation
DFO has gone to considerable lengths to convince the public that the seal hunt in Canada is conducted humanely. Most recently in this regard, we received at the seal forum the report of the “Independent Veterinarian’s Working Group on the Canadian Harp Seal Hunt.” Similar attention now needs to be paid by DFO to proving to the public that the seal hunt is truly “sustainable” and that the management of the seal hunt is “ecosystem-based” and is following the principle of “erring on the side of caution.”
GSCS recommends that DFO act now to convene a panel of impartial experts in marine predator ecology and ecosystem-based fishery management for the purpose of eliciting their advice on how ecosystem considerations should be incorporated into planning the Canadian seal hunt. It is advised that DFO partner with external conservation organizations in organizing this panel. “Erring on the side of caution” in this matter will mean withholding approval for any new seal management plan until the report of the recommended panel is completed.
Finally, DFO should implement a regular, formal mechanism to allow stakeholders outside the fishing industry to become involved in providing advice to scientists on the management of natural resources. Along the same vein, it would be useful at this time if DFO were to initiate the organization of an “Environmentalists and Scientists Research Society” patterned after the “Fishermen and Scientists Research Society” that has existed for the past decade.
(1) Oceans Act (1996)
(2) Canada’s Oceans Strategy (2002)
(3) Pikitch, E. K. et al. 2004. Ecosystem-Based Fishery Management. Science 305: 346 - 347
(4) O’Boyle, R., M. Sinclair, P. Keizer, K. Lee, D. Ricard, and P. Yeats. 2004. Operationalizing an Ecosystem Conservation Framework for the Eastern Scotian Shelf. DFO Can. Sci. Advis. Sec. Res. Doc. Ser. 2004/076
(5) DFO, 2004. Habitat Status Report on Ecosystem Objectives. DFO Can. Sci. Advis. Sec. Habitat Status Report 2004/001.
(6) Eastern Scotian Shelf Integrated Ocean Management Plan (2006-2011) Draft for Discussion. DFO Oceans and Coastal Management Report 2005-02
(7) Frank, Kenneth T., Brian Petrie, Jae S. Choi, and William C. Leggett. 2005. Trophic Cascades in a formerly Cod-dominated Ecosystem. Science 308: 1621 - 6123
(8) 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: xii + 193 p.
(9) Choi, Jae S., Kenneth T. Frank, William C. Leggett and Ken Drinkwater. 2004. Transition to an alternate state in a continental shelf ecosystem. Can. J. Fish. Aquat. Sci. 61: 505 – 510
(10) DFO, 2003. State of the Eastern Scotian Shelf Ecosystem. DFO Ecosystem Status Report 2003/004.
(11) Jackson, Jeremy B. C. et al. 2001. Historical Overfishing and the Recent Collapse of Coastal Ecosystems. Science 293 (5530): 629 – 637.
(12) Myers, R. A. and B. Worm. 2005. Extinction, survival or recovery of large predatory fishes. Proceedings of the Royal Society B. 360: 13 - 20
(13) Pauly, D. and J. Maclean. 2002. In a Perfect Ocean: the state of fisheries and ecosystems in the North Atlantic Ocean. Island Press, USA