Evaluation of the nursery role of wetlands and seagrasses for better conservation and management

Wetland (herein, estuarine marsh and mangrove) and seagrass habitats are extraordinarily productive, and are believed to play a nursery role in which juvenile fish and shellfish occur at high densities, avoid predation, grow quickly, and then migrate offshore to appropriate adult habitat. The nursery role of these habitats is a pervasive concept, and it is important in research, conservation, and management. There is, however, growing recognition that the evidence that supports this paradigm is not cohesive and sometimes weak or contradictory. A clear understanding of the importance of seagrass and wetland habitats in the life cycles of marine species is urgently needed, because these habitats are declining rapidly worldwide. In the USA, the recently revised Magnuson Fishery Conservation and Management Act requires all eight Regional Fishery Management Councils to define, protect, and restore "Essential Fish Habitat". If seagrasses and wetlands are nursery grounds then new measures can and should be directed towards their conservation as Essential Fish Habitat.

Our goal is to form three small working groups to critically evaluate the nursery role concept for seagrass and wetland habitats. We will determine the extent to which the density, survival, and growth of animals are greater in these habitats than elsewhere and examine the characteristics of these habitats that most affect secondary productivity. We will also use bioenergetic simulation models to estimate the contribution of seagrasses and wetlands to offshore secondary production and examine the predicted effects of the continued loss of these habitats. We plan to synthesize and make these results useful not only to scientists but also to NGO's, and state and government agencies to better inform management and conservation of coastal environments.