SMRU Consulting are delighted to announce that our review of the Methods for Monitoring for the Population Consequences of Disturbance (PCoD) in Marine Mammals has been published and is now available in Frontiers in Marine Science.

SMRU Consulting have worked together with John Harwood (CREEM) to build a review of the available literature on the best methods for monitoring marine mammals to inform the PCoD model, and describe how future marine mammal monitoring programs can be designed to inform such population-level analysis.

When assessing the non-lethal effects of disturbance, and the consequences this may have at the population-level, models require extensive baseline knowledge of behavioural patterns, life-history and demography for that species and population. For marine mammal mammals, this knowledge is often lacking. In addition, detecting a change at the population level in marine mammal species is challenging – both because typical survey methods (monitoring the population size or density in a given area) rarely have the power to reliably detect changes. So relying on such approaches mean we can only detect changes when it is too late. So we are really most interested in identifying early warning signs that could reliably identify where populations are changing markedly.

To address these problems, we reviewed the literature and identified the most suitable response variables and methods to monitor these variables. A workshop was conducted to establish the relative utility and feasibility of these approaches for different groups of marine mammal species and the outcomes are summarised.

We then present outputs from existing PCoD models to identify which demographic characteristics (e.g., the proportion of immature animals in the population, or the ratio of calves/pups to mature females) are strongly correlated with population status and therefore could provide early warnings of future changes in abundance. We discuss how these demographic characteristics can be monitored using established methods such as visual surveys combined with photogrammetry, and capture-recapture analysis. We also outline how individual health and physiological variables can be monitored using photogrammetry, remote tissue sampling, hands-on assessment and individual tracking.

To read more, click here.

Reference

Booth, C. G., Sinclair, R. R., & Harwood, J. (2020). Methods for Monitoring for the Population Consequences of Disturbance in Marine Mammals: A Review. Frontiers in Marine Science, 7, 115. doi.org/10.3389/fmars.2020.00115