Question 3 Response--Concerning next successive steps to be taken, the comments, as in question 1, ranged from needed modeling efforts to needed empirical observations, and interactions of both. Several participants recommended that physics and biology needed to be closely coupled not only in modeling but also in field observations, and that modeling and field observations be coupled by design. One participant suggested "to hold empiricists' feet to the modeling fire"! One approach for facilitating this interaction is to develop generic models that can be used widely and have the flexibility to incorporate knowledge and measurements from different locales and regions.
An understanding of detailed mechanisms (of recruitment dynamics) is needed. Appropriate models must be formulated and their implications assessed. Several steps, however, need to be taken to obtain such an understanding. They include smallŠscale animal behavior (0.1 to 100 m vertically) and its coupling to physics and food distribution; data on effects of behavior on growth and predation mortality; data on in situ growth rates of different stages (no more black box approaches, such as using biomass) of target species; and eventually a smallŠscale feeding model should be constructed to integrate feeding behavior, turbulence and smallŠscale patchiness. In addition, a thorough ecosystem monitoring was recommended to capture eventŠscale phenomena (=continuous in situ observations). For example, continuous assessment of the spatial and temporal structure of water column variables would allow us to parametrize heterogeneity.
Above all, there appears to be a need for a unifying conceptual basis. To foster this development, a rigorous review of what has been done should be undertaken. This review would be two-fold. The first part would focus on what has been done in marine secondary production as well as what has been done in other related fields, such as evolutionary biology. The second part would focus on models that have done a satisfactory (or not) job of handling secondary production. Sponsorship of such reviews was thought to be within the stated objectives of U.S. GLOBEC.