Knowledge on microplastic (MP) ingestion by cetaceans is difficult to obtain. We infer the potential for MP uptake by cetaceans from the occurrence of MP in prey species. First, we reviewed information on whale prey species, focussing on common minke (Balaenoptera acutorostrata) and sei whale (B. borealis), for which the most comprehensive quantitative datasets exist. Second, evidence of MP ingestion by their prey species was reviewed. We found common minke whales forageopportunistically on fish from various families: Ammodytidae, Clupeidae, Gadidae, Engraulidae and Osmeridae. Sei whales mostly feed on copepods, Engraulidae, Clupeidae and Scombridae. High levels of MP contamination are reported for Scombridae in the Atlantic and Engraulidae in the Northwest Pacific Ocean. Copepods exhibit low levels of MP ingestion in the Northeast Pacific Ocean. Species-specific prey preferences and feeding strategies imply different cetaceans have varied potential for MP uptake, even if they feed in similar geographic areas.
The natural capital of the vast deep ocean is significant yet not well quantified. The ecosystem services provided by the deep sea provide a wide range of benefits to humanity. Proposed deep-sea economic activities such as fishing, deep-sea mining and bioprospecting therefore need to be assessed in this context. In addition to quantifying the economic benefits and costs of such activities on their own, their potential impact on the deep-sea natural capital also needs to be considered.
This article describes such a natural capital approach, identifies relevant ecosystem services and looks at how a range of proposed commercial activities could be assessed in this context. It suggests a methodology for such analysis and suggests an approach to a sustainable blue deep-sea economy that is consistent with environmental precaution. It will close with suggestions of how potential risks can best be handled.
The article aims to show that modern environmental economics based on natural capital can provide a useful framework for deciding future deep-sea efforts.
Using the production and trade data of marine shellfish extracted from the database of FishStatJ, this study aims to i) measure development level (DL) of the marine shellfish industry (MSI) in 10 major producing countries by the TOPSIS model; ii) classify the MSI into different classes in term of the results from the above measurement; and iii) identify, by the variation coefficient, how DL of the MSI in the 10 countries was changing during the period of 1997–2016.
The results of the TOSIS analysis indicate that, by the relative closeness and the number of turning points, the 10 countries can be divided into three types, i.e., with no change (China and Thailand); with little change and in a gradual way (Japan, Canada, France, Spain and Italy); and with a dramatical change (USA, Chile and South Korea). In term of the mean of relative closeness, the 10 countries can be divided into four classes, i.e., excellent (class I), good (class II), weak (class III), and poor (class IV), with China being in class I, USA, Japan and Canada in class II, France, Chile, Spain and South Korea in class III, and Italy and Thailand in class IV.
The results of the variation coefficient analysis suggest that the difference in DL of the 10 countries’ MSI increased over the past 20 years. In particular, the difference among the developing countries increased significantly, while those between the developed countries shrank slightly.