Development of a new control rule for managing anthropogenic removals of protected, endangered or threatened species in marine ecosystems

• Published in: PeerJ
• Main Authors: Ouzoulias, Fanny, Bousquet, Nicolas, Genu, Mathieu, Gilles, Anita, Spitz, Jérôme, Authier, Matthieu
• Other Authors: The French Ministry in Charge of Ecology, The German Federal Agency for Nature Conservation funded Anita Gilles’s time as the lead of the OSPAR expert group on marine mammals
• Format: Article in Journal/Newspaper
• Language: English
• Published: PeerJ 2024
• Subjects: Harbour porpoise; North East Atlantic; Phocoena phocoena
• Online Access: http://dx.doi.org/10.7717/peerj.16688; https://peerj.com/articles/16688.pdf; https://peerj.com/articles/16688.xml; https://peerj.com/articles/16688.html

Human activities in the oceans are increasing and can result in additional mortality on many marine Protected, Endangered or Threatened Species (PETS). It is necessary to implement ambitious measures that aim to restore biodiversity at all nodes of marine food webs and to manage removals resulting from anthropogenic activities. We developed a stochastic surplus production model (SPM) linking abundance and removal processes under the assumption that variations in removals reflect variations in abundance. We then consider several ‘harvest’ control rules, included two candidate ones derived from this SPM (which we called ‘Anthropogenic Removals Threshold’, or ART), to manage removals of PETS. The two candidate rules hinge on the estimation of a stationary removal rate. We compared these candidate rules to other existing control rules ( e.g. potential biological removal or a fixed percentage rule) in three scenarios: (i) a base scenario whereby unbiased but noisy data are available, (ii) scenario whereby abundance estimates are overestimated and (iii) scenario whereby abundance estimates are underestimated. The different rules were tested on a simulated set of data with life-history parameters close to a small-sized cetacean species of conservation interest in the North-East Atlantic, the harbour porpoise ( Phocoena phocoena ), and in a management strategy evaluation framework. The effectiveness of the rules were assessed by looking at performance metrics, such as time to reach the conservation objectives, the removal limits obtained with the rules or temporal autocorrelation in removal limits. Most control rules were robust against biases in data and allowed to reach conservation objectives with removal limits of similar magnitude when averaged over time. However, one of the candidate rule (ART) displayed greater alignment with policy requirements for PETS such as minimizing removals over time.