Scale-dependence of seabird-fishery data analysis and management: Reply to Croxall et al. (2013)

Croxall et al. (2013; Mar Ecol Prog Ser 493:297-300) assert that fine-scale analysis of seabird-fisheries overlap, such as that presented in Torres et al. (2013; Mar Ecol Prog Ser 473:275-289), is of limited value for the assessment and management of seabird bycatch. In contrast, we consider that the highly dynamic movement patterns of both seabirds and fishing vessels necessitate analyses at multiple scales to fully understand the spatio-temporal variation in their associations. Conservation management of seabird bycatch in fishing operations can be applied at multiple scales from large ocean basins to small sub-national management units. We argue that the appropriate scale of analysis of seabird−fishery overlap is dependent on the data available and on the scale of management to be applied. The criticism by Croxall et al. (2013) of our analytical methods and interpretation of results does not affect the derived rates of overlap between Buller’s albatrosses and fishing vessels. Studies of seabird-fisheries overlap at all scales are trending toward analyses at smaller spatial and temporal scales, supporting the conclusion of Torres et al. (2013) that scaling down such analyses is valuable for improving our ecological understanding of seabird-fishery associations and for the conservation management of seabird bycatch.

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