Cetaceans as Ocean Health Indicators of Marine Litter Impact at Global Scale

Maria Cristina Fossi,Matteo Baini,Mark Peter Simmonds

doi:10.3389/fenvs.2020.586627

Maria Cristina Fossi, Matteo Baini + Show 1 more

Open Access

https://doi.org/10.3389/fenvs.2020.586627

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Abstract

Marine litter is a growing concern for marine animals, including cetaceans for which there is a developing body of evidence showing impacts of both entanglement and ingestion. Better understanding is needed of the current and predicted scales of impacts on cetacean species of both macro- and micro-litter. Some emerging methodological approaches, such as the “threefold approach,” will help address data gaps. The relationship between this form of pollution and some cetaceans is strong and the particular feeding habits, and widespread distribution of two whale species means that they can be proposed as ocean health indicators for macro- and micro-litter impacts at global scales, helping steer research. The species concerned are sperm whales (Physeter macrocephalus), for macro-litter at depth, and fin whales (Balaenoptera physalus), for micro-debris. Once appropriate techniques have been fully developed for non-lethal assessment, other whale species might also be used as indicators of litter pollution in their specific feeding zones.

Highlights

The effects of marine debris on marine wildlife have been documented since the 1960’s (CBD, 2016; Germanov et al, 2018)
While other deep diving cetacean species, including for example Cuvier’s beaked whales, Ziphius cavirostris, seem to be highly susceptible to the ingestion of marine litter (e.g., Baulch and Perry, 2014; Fossi et al, 2018a; International Whaling Commission (IWC)., 2020), we propose that the long-lived sperm whales are the better indicator because they are more cosmopolitan, their bodies are probably more likely to be retrieved and their biology is better known
The idea of cetaceans as indicators of oceans health has attracted the attention of the scientific community, other stakeholders and the media

Summary

INTRODUCTION

The effects of marine debris on marine wildlife have been documented since the 1960’s (CBD, 2016; Germanov et al, 2018). Fossi et al (2014) found organochlorines and a phthalate metabolite were higher in a stranded Mediterranean fin whale than in a basking shark, suggesting that fin whales are more heavily impacted by micro-litter and a stronger candidate as an indicator species than other filter feeders These marine animals are susceptible to high levels of microplastics ingestion and potential exposure to associated toxic compounds due to their feeding strategies and the overlap between their habitats and microplastic hot spots. The feeding mechanism of sperm whales is not fully understood Their relatively small lower jaw and large peg-like teeth that fit into sockets on the upper jaw reflect the fact that they can grasp items, including prey, but suction is very probably involved (Fais et al, 2016), which may explain their seemingly high levels of ingestion of marine debris. The Sperm Whale is proposed here as ocean health indicator of marine litter impact in deep seas at a global scale

DISCUSSION AND CONCLUSION

DATA AVAILABILITY STATEMENT