The goal of the GLOBEC Small Pelagic Fish and Climate Change (SPACC) programme is to understand and predict climate-induced changes in the fish production of marine ecosystems. In addition to having broad economic and ecologic importance, this goal is especially pertinent today because of the expected changes in the earth climate over the next hundred years and their impact on the oceans and marine life.
Small pelagic fishes are an ideal subject for the study of the effects of climate change on marine ecosystems because they are globally distributed and constitute over a third of the global marine fish catch. Moreover, by having a short life span and by feeding on the plankton-based food chains, they respond rapidly to changes in ocean forcing. Ocean-wide decadal swings in abundance have been identified and are thought to be environmentally driven. Lastly, time series of catches and abundance offer a rich data resource for retrospective data analyses.
The Small Pelagic Fish and Climate Change programme is a major component of the GLOBEC field research programme. An aim is to identify those physical forces that control the dynamics of small pelagic fish populations. Modelling is also a key issue for SPACC. By using a combination of retrospective data analyses, process studies and modelling experiments, the long-range goal of SPACC is to provide scenarios of the changes in the abundance and distribution of small pelagic fish populations caused by human- and naturally induced climate changes.
The approach of SPACC is to compare the characteristics and variability of the physical environment, zooplankton population dynamics, and fish population dynamics among ecosystems. SPACC involves:
- Retrospective studies, in which ecosystem histories are reconstructed by means of time series, paleoecological data, and genetic data.
- Process studies, in which cause-and-effect linkages between fish population dynamics and ocean climate are investigated and compared between ecosystems
The SPACC science and implementation plans were designed in the late 1990s (see GLOBEC Reports 8 and 11). They were revised in 2000 to increase focus and ensure maximum use of resources. SPACC is organised along four major scientific themes:
- Long-term changes in ecosystems: retrospective analyses
- Comparative population dynamics
- Reproductive habitat dynamics
- Economic implications of climate change