DIRECTOR'S FOREWORD

There is, in the Fisheries Centre, a strong emphasis on global assessments and databases, but it is also true that British Columbia and the eastern North Pacific are our hinterland, and the place where the Marine Mammal Research Unit concentrates much of its field work. It is thus appropriate that Edward Gregr and Ryan Coatta have completed and made available for wider distribution a dataset of special information on temperatures, chlorophyll and other environmental parameters for the eastern North Pacific.

All ecosystem modelling work which researchers based at the Fisheries Centre have done in various subsystems of the Eastern North Pacific confirms that both top-down and bottom-up effects shape the dynamics of the ecosystem and the fluctuation of individual species. This insight is not as obvious as it seems: there are ecosystems where changes in fishing regime are all that is needed to explain the different ecosystem states that are observed, and the changed abundances of the species embedded therein. This does not apply to the eastern North Pacific. Conversely, there are ecosystems that are driven predominantly from the bottom-up. The eastern North Pacific is not among those either, notwithstanding much talk about all-encompassing regime shifts. Rather, the eastern Noth Pacific ecosystem appears to be genuinely controlled both by bottom-up and top-down processes, acting simultaneaously, if with different intensities, on the different species groups within the system.

This combination of top-down and bottom-up controls can, in many cases, only be demonstrated by judicious choice of the scale at which local data sets are thought to apply. It is therefore extremely helpful to have a choice. The data sets presented in this report will help in this, as they range in coverage from the entire eastern North Pacific (120E to 155W, and 31.6N to 66.5N), through an intermediate scale covering the northeast Pacific and the Bering Sea (130E to 170W, and 50N to 65N), to as higher resolution dataset of the Gulf of Alaska (129E to 166E, and 51N to 61N).

Finally, I want to laud the authors for devoting much energy to assembling and documenting their datasets such that they not only will later back their own work, but can be used by others working on the eastern North Pacific. Selfless undertakings of this sort are uncommon enough to deserve special praise. .

Daniel Pauly
Director, Fisheries Centre

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