A Review of the Welfare Impact on Pinnipeds of Plastic Marine Debris

Andy Butterworth

doi:10.3389/fmars.2016.00149

Abstract

Uncounted, and usually unobserved, numbers of pinnipeds find themselves entangled in lost fishing gear, monofilament line, nets, rope, plastic packaging in the ocean or on the shoreline. These animals may carry debris wrapped around themselves for long periods, and often die as a result, sometimes from deep chronic wounds. The pinniped species most affected by this modern and manmade phenomenon are fur seals, monk seals, and California sea lions, and to a lesser extent grey, common and monk seals. Entanglement rates described range up to 7.9% of local populations annually, and the common entangling materials; packing bands, fragments of lost net, rope, monofilament line, fishery flashers and lures, long-line fishing gear, hooks and line, and bait hooks are discussed. Awareness of this issue is increasing, and local action is reported to have made measurable differences in entanglement rates, however, plastic material in the ocean is likely to be long lived, and will leave many entangled pinnpeds unreported and result in a hidden and potentially significant effect on wild animal welfare.

Highlights

Uncounted, and usually unobserved, numbers of the animals that live in the oceans find themselves snared, trapped, or entangled in lost fishing gear, monofilament line, nets, rope, plastic packaging, packing bands from crates, or become hooked on discarded fishing gear, or ingest human marine debris
This study indicated that entanglement was more commonly observed from July to October, when the young animals approached weaning, and using a Generalized Additive Mixed Models (GAMMs) these authors estimated that 1.0% (CI = 0.6–1.7%) of the local population was entangled each year
Pinnipeds are at the visible end of the spectrum of animals which become entangled, snared, trapped or caught in marine debris, plastics in the form of net, rope, monofilament line and packing bands, with severe consequences, and the potential for acute welfare impacts on the individual animals

Summary

A Review of the Welfare Impact on Pinnipeds of Plastic Marine Debris

Clinical Veterinary Science, University of Bristol Veterinary School, Bristol, UK. Reviewed by: Julia Ann Jabour, University of Tasmania, Australia Christian T. Entanglement rates described range up to 7.9% of local populations annually, and the common entangling materials; packing bands, fragments of lost net, rope, monofilament line, fishery flashers and lures, long-line fishing gear, hooks and line, and bait hooks are discussed. Awareness of this issue is increasing, and local action is reported to have made measurable differences in entanglement rates, plastic material in the ocean is likely to be long lived, and will leave many entangled pinnipeds unreported and result in a hidden and potentially significant effect on wild animal welfare

INTRODUCTION

Findings

CONCLUSIONS