For Unilever, this loss of legitimacy should the MSC fail will be compounded by a loss of the commercial supply of the world's fish, which will create a major loss of profits for the company. It would also greatly hurt the company's image with both consumers and environmentalists, as well as with their suppliers in the fishing and other industries. This last could be of incredible detriment to the company; if the policies it encourages its suppliers to adopt and implement ultimately lead to their failure, the level of trust between Unilever's many suppliers and the international food and consumer product will be hugely diminished, likely irrevocably. This will make it highly difficult for Unilever -- and possibly any other large company -- to engage in similar projects in the future. The World Wildlife Fund also faces a great loss of trust and stature should the Marine...

There is already a great deal of skepticism regarding the environmental group's partnership with Unilever, and a failure would only confirm these doubts (Radler 2000). Again, this would make it incredibly difficult for similar partnerships to be formed in the future, and the environmental movement would likely be put even more at odds with business interests -- at least, in many of the minds of the individuals and groups that male up the environmental movement -- than it was before the Marine Stewardship Council was formed. A failure here would also hurt the trust level in many of the WWF's other endeavors, as well.
References

Radler, G. (2000). "The marine stewardship council: Is a joint venture possible between

"suits and sandals"? International institute for management and development.