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Monitoring ecosystems using research surveys; maximizing information and minimizing cost
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Original versionThis report is not to be cited without prior reference to the authors
Indices or estimates of abundance generated by research vessel surveys are becoming ever more important for assessing marine resources. Most often survey abundance indices are used in conjunction with commercial catch data to estimate fishing mortalities and stock size. However, for short-lived species (e.g. capelin) survey indices provide the only reliable information on stock development and even for long-lived species (e.g. cod), it has been shown that calibrated survey estimates tracked recent abundance trends more accurately than catch-based estimates. Multipurpose research surveys provide information on the spatial and temporal patterns of environmental and biological variables, which has enhanced our understanding of ecosystem interactions, assessment and management. The information needed for the ecosystem approach to management is increasing the importance of conducting multipurpose surveys, which is affecting vessel configuration and survey design. In this paper we examine the survey design and sampling routines for some IMR surveys and suggest ways to improve their efficiency, i.e. the utilization of vessel time.