Scaling marine fish movement behavior from individuals to populations. Issue 14 (25th June 2018)

• Record Type: Journal Article
• Authors: Griffiths, Christopher A.; Patterson, Toby A.; Blanchard, Julia L.; Righton, David A.; Wright, Serena R.; Pitchford, Jon W.; Blackwell, Paul G.
• Is Part Of: Ecology and evolution. Volume 8:Issue 14(2018)
• Page Start: 7031
• Page End: 7043
• Publication Date: 2018-06-25
• Subjects: Atlantic cod -- data storage tags -- European plaice -- hidden Markov modeling -- movement behavior -- population‐level patterns -- priors; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.4223
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: Understanding how, where, and when animals move is a central problem in marine ecology and conservation. Key to improving our knowledge about what drives animal movement is the rising deployment of telemetry devices on a range of free‐roaming species. An increasingly popular way of gaining meaningful inference from an animal's recorded movements is the application of hidden Markov models (HMMs), which allow for the identification of latent behavioral states in the movement paths of individuals. However, the use of HMMs to explore the population‐level consequences of movement is often limited by model complexity and insufficient sample sizes. Here, we introduce an alternative approach to current practices and provide evidence of how the inclusion of prior information in model structure can simplify the application of HMMs to multiple animal movement paths with two clear benefits: (a) consistent state allocation and (b) increases in effective sample size. To demonstrate the utility of our approach, we apply HMMs and adapted HMMs to over 100 multivariate movement paths consisting of conditionally dependent daily horizontal and vertical movements in two species of demersal fish: Atlantic cod ( Gadus morhua ; n = 46) and European plaice ( Pleuronectes platessa ; n = 61). We identify latent states corresponding to two main underlying behaviors: resident and migrating. As our analysis considers a relatively large sample size and states are allocated consistently, we use collective model output to investigate state‐dependent spatiotemporal trends at the individual and population levels. In particular, we show how both species shift their movement behaviors on a seasonal basis and demonstrate population space use patterns that are consistent with previous individual‐level studies. Tagging studies are increasingly being used to inform stock assessment models, spatial management strategies, and monitoring of marine fish populations. Our approach provides a promising way of adding value to tagging studies because inferences about movement behavior can be gained from a larger proportion of datasets, making tagging studies more relevant to management and more cost‐effective. Abstract : Tagging studies are increasingly being used to inform stock assessment models, spatial management strategies, and the monitoring of marine fish populations. One criticism of tagging studies is that they often lack in sample size, limiting a researcher's ability to ask population‐ and management‐level questions of their data. By introducing a novel adaptation to the behavioural classification of movement observations, we demonstrate how researchers can use a combination of data‐rich and data‐poor movement paths to infer population‐level space use patterns, ultimately making tagging studies more cost‐effective and more relevant to management objectives.