which they might fail, and the appropriateness of variations on the themes. Some of these questions and practical experiences with ITQs have been discussed by McCay and her coworkers (McCay 1995, McCay et al. 1995) and OECD (1997). Concerns about ITQs include questions about equity (e.g., the assignment to individuals of exclusive rights to exploit resources that are perceived to belong to everyone and whether the shares should be given away or sold), concentration of the rights or shares in very few people's hands, questions about their effectiveness in promoting stewardship, their effect in reducing the number of participants in fisheries, the best extent and duration of the rights or shares, and other related concerns. In addition to researching those concerns, there is room to consider broadening the scope of the virtual communities, especially if one views fisheries in an ecosystem context. Should timber interests be included in salmon-fishery virtual communities, for example?
Hanna (1998) provided an analysis of ways to adapt institutions and property-rights regimes to an ecosystem approach to fishery management that reflects attributes of the ecosystem and its human users, values ecosystem services, and coordinates interest groups and managers on a broad ecosystem scale (see also NRC 1996b). Management structures need to promote the definition of multiple objectives through processes that are legitimate and flexible and that promote socially appropriate time horizons for resource use and decision making. They need to take uncertainties into account, including what Hanna calls fact uncertainty (lack of knowledge) and tenure uncertainty (resulting from unspecified property rights or uncertainty in political systems). Despite these uncertainties, the recent developments of various rights-based allocation schemes offer considerable hope for sustainable fishery management. Indeed, it not clear what other general course offers as much promise.
Managing complex biological systems is difficult because of the often large differences between the social and temporal scales of natural and socio-political systems (NRC 1996a, 1996b). Although incentive structures created by allocating transferable use rights to private entities may promote greater efficiency and new ways of valuing the resources, unless they are designed correctly, they may not by themselves adequately protect and enhance ecosystem goods and services by protecting habitat, preventing pollution, and coordinating with other fisheries (Scott 1993). Hence, other forms of organization, including comanaging and virtual communities, are needed as well. In the broader sense of rights-based fishery management advanced in this report, different kinds of rights, ranging from rights to a resource to rights of governance, would be combined with different forms of ownership, ranging from individual ownership to ownership by communities and to ownership by the public or national government. The public-trust nature of marine resources as well as public rights in the ecosystem goods and services provided by marine environments (Rieser 1991) can be combined with private and community-based ownership of rights, access, capture, and management