Physiological ecology in cold ocean fisheries: a case study in Atlantic cod

Summary

Despite a long and distinguished history of scientific investigation in marine fisheries research, there remain a large number of gaps in our knowledge of the processes that determine both the numbers and sizes of the animals produced. The major problem is one of the enormous domain within which the production system occurs, with physical and biological coupling mechanisms operating over temporal and spatial scales of several orders of magnitude. In practical terms, these varying scales represent different subdisciplines in marine fisheries science, e.g. ranging from the physics of large oceanic structures to the physical structure of the genetic material of the biological components. When working in isolation, each subdiscipline can offer descriptive interpretations appropriate to its own scale of study. But when combined within the same theoretical and experimental paradigm, they can consolidate to offer mechanistic insight into the dynamic processes regulating population quality and quantity.

Figure 1 outlines the marine fish production process and can, with appropriate differences in emphasis, represent either an aquaculture-based or harvest-based fishery, the latter being the main emphasis of this report. As with any biological system, the main building blocks are the genetic materials present in the gene pools of the populations in question. These genetic elements interact in both time and space with physical–biological coupling processes to affect both the numerical yield (i.e. through natural mortality), as well as the size and/or quality of each numerical component (i.e. through the imposition of bioenergetic costs).