Declining fisheries production is a direct result of over-fishing and destructive fishing practices, not competition from whales or any other part of the marine ecosystem. Marine ecosystems are incredibly complicated and inter-connected systems. It is simply not possible to predict the implications of artificial changes to such complex systems with any certainty. Given this uncertainty, Greenpeace strongly argues that we must adopt a precautionary approach and avoid any activities that may affect the integrity of marine ecosystems.

From, "Do Large Whales Have an Impact on Commercial Fishing in the South Pacific Ocean?", Jock W. Young, JOURNAL OF INTERNATIONAL WILDLIFE LAW & POLICY (2000). Conclusion Before industrialised fishing began, the marine environment, with all its components, would have evolved to a steady state (fluctuating environmental factors permitting). Therefore, in the past, when whale populations were far larger, there was obviously enough fish and plankton to sustain them, and enough left over to support the huge global fish stocks that have been exploited by modern day fisheries. The partial recovery of some whale populations over the past 30 years cannot begin to explain the decline in fisheries worldwide. A recent review of the ecological importance of cetaceans114 concluded that it was as yet unclear whether cetaceans have a "positive or negative effect on fisheries", but that there is "no concrete evidence for cetaceans harming fisheries." The available literature widely supports this perspective. However, the greatest hindrance to developing the argument further is lack of appropriate data, especially abundance and trophic data. In fact, given the available data, it is just as plausible that increasing the abundance of cetaceans has a positive effect on fisheries through the former preying on squid, a major predator of juvenile fish.

In fact, independent scientists have raised serious concerns that culling top order predators such as whales would further reduce the productivity of important fisheries. Marine mammal predators also feed on other predatory species that in turn feed on fish species consumed by humans.

Removing top predators such as toothed whales would then cause increased numbers of predatory species, which would then in turn be able to take more of the commercially important species.

The notion of culling or harvesting whales has depended in part upon the flawed premise that whale populations are dramatically increasing with negative impacts upon global fisheries. This is simply untrue. It should be remembered that due to whaling, most global whale populations have been drastically reduced far below their original levels.

Why is fishing okay and not commercial whaling?

Over-fishing is a big problem, even though fish breed quite prolifically. Whales and fish have a very different reproductive biology. Most fish reproduce by releasing huge numbers of eggs into the water. Most do not survive, but as long as there are good conditions for the young fish to grow, the eggs from a small percentage of the population can quickly regenerate the whole population.

In contrast, whales are mammals and have only a single offspring at a time, which needs at least a year of maternal care before it can survive on its own and many years before it can reproduce. As a result of these biological characteristics, whales are highly susceptible to over-exploitation and can never recover quickly from overexploitation.