Evolution of global marine fishing fleets and the response of fished resources Yannick Rousseaua,b,c,1, Reg A. Watsona,b, Julia L. Blancharda,b, and Elizabeth A. Fultonb,c aInstitute for Marine and Antarctic Studies, University of Tasmania, 7004, Battery Point, Australia; bCentre for Marine Socioecology, 7004 Battery Point, Australia; and cOceans and Atmosphere, Commonwealth Scientific and Industrial Research Organisation, 7004, Battery Point, Australia Edited by Ray Hilborn, University of Washington, Seattle, WA, and accepted by Editorial Board Member David W. Schindler April 18, 2019 (received for review December 4, 2018) Previous reconstructions of marine fishing fleets have aggregated regional definitions. The industrial fleets are better documented data without regard to the artisanal and industrial sectors. Engine and reported than artisanal fleets (9), specifically how they de- power has often been estimated from subsets of the developed veloped to exploit often distant fish stocks, which could not be world, leading to inflated results. We disaggregated data into fished efficiently by artisanal fishers. Recent technological prog- three sectors, artisanal (unpowered/powered) and industrial, and ress, particularly in electronic monitoring systems, has provided a reconstructed the evolution of the fleet and its fishing effort. We substantial volume of information on the composition and behavior found that the global fishing fleet doubled between 1950 and of the larger components of the industrial fleet (10). In contrast, 2015—from 1.7 to 3.7 million vessels. This has been driven by sub- the extent and impact of the artisanal fishing fleet is under- stantial expansion of the motorized fleet, particularly, of the estimated in the literature. This paper aims to strengthen the powered-artisanal fleet. By 2015, 68% of the global fishing fleet knowledge of the global marine fishing fleets by reconstructing the was motorized. Although the global fleet is dominated by small number and engine power of artisanal and industrial fishing vessels. For centuries, fishing vessels used sails and oars as propulsion powered vessels under 50 kW, they contribute only 27% of the methods. The introduction of steam-powered trawlers and the global engine power, which has increased from 25 to 145 GW subsequent improvements in propulsion had a dramatic effect on (combined powered-artisanal and industrial fleets). Alongside an the efficiency of fishing vessels, their spatial reach, and on expansion of the fleets, the effective catch per unit of effort (CPUE) landings; perhaps best documented in the Northern Atlantic SCIENCES has consistently decreased since 1950, showing the increasing pres- (11). Whereas the focus nowadays is on industrial fishing oper- ENVIRONMENTAL sure of fisheries on ocean resources. The effective CPUE of most ations, a vast portion of global fishing still occurs at artisanal countries in 2015 was a fifth of its 1950s value, which was compared levels (12, 13). Furthermore, as the research on fisheries is bi- with a global decline in abundance. There are signs, however, of ased toward the developed world, the impact of the unpowered stabilization and more effective management in recent years, with a artisanal fishing fleet is often overlooked in academic studies. As reduction in fleet sizes in developed countries. Based on historical up to a quarter of fishing vessels are unmotorized globally (1), patterns and allowing for the slowing rate of expansion, 1 million neglecting this component of the fleet and its transition through more motorized vessels could join the global fleet by midcentury as technological advances results in vast underestimates of the SCIENCE developing countries continue to transition away from subsistence impact of fishing, particularly, in the poorest parts of the world. SUSTAINABILITY fisheries, challenging sustainable use of fisheries’ resources. Improved understanding of the motorization of the fishing fleet and taking a step back from focusing almost exclusively on de- fishing capacity | effort | CPUE | artisanal | industrial tailed industrial fleets are fundamental for both reconstructing arine fisheries support global food security (1), human Significance Mlivelihood, employment (2), as well as global trade (3) and will continue to do so in the foreseeable future with the benefit We independently reconstructed vessels number, engine of wise management. power, and effort of the global marine fishing fleet, in both the Understanding fishing capacity is paramount to its manage- artisanal and industrial sectors. Although global fishing ca- ment (4) and failure to manage fisheries compromises all of the pacity and effort have more than doubled since 1950 in all but services these vital resources offer. Although the importance of the most industrialized regions, the nominal catch per unit of knowledge of fish stocks is undeniable, it cannot be disassociated effort (CPUE) has comparatively decreased. Between 1950 and from the fishing processes themselves. Catch per unit of effort 2015 the effective CPUE, among the most widely used indicator (CPUE) is still a widely used measure of the well being of a to assess fisheries management and stocks well being, has fished stock (5), which cannot be estimated without some mea- decreased by over 80% for most countries. This paper high- sure of the fishing capacity, defined hereafter in its simplest lights the large differences in the development of sectorial form—the number of existing fishing boats. Although there has fishing fleets regionally. This detailed paper empowers future been significant work to collect global fishing fleet data, most exploration of the drivers of these changes, critical to develop notably by the United Nation’s Food and Agriculture Organiza- sector and regionally specific management models targeting tion (FAO), gaps in the data are nontrivial, and no satisfying global fisheries sustainability. method has been found that fills them and allows for comparison or prediction without major and often flawed assumptions (6). Author contributions: Y.R., R.A.W., J.L.B., and E.A.F. designed research; Y.R. performed Although progress has been made toward reconstructing the research; Y.R. analyzed data; R.A.W. provided extra analytical tools and data; and Y.R. historical size and power of the global fishing fleet (6, 7), several wrote the paper. inconsistencies are apparent in the results. This is partially be- The authors declare no conflict of interest. cause public records aggregate disparate fishing fleets into one This article is a PNAS Direct Submission. R.H. is a guest editor invited by the component as if they were easily interchangeable units. It is, Editorial Board. however, well understood that global fishing fleets consist of, at Published under the PNAS license. least, two separable components: “artisanal” and “industrial,” 1To whom correspondence may be addressed. Email: [email protected]. the former comprising both motorized and unmotorized ele- This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10. ments. These components of the fleet, although interacting, are 1073/pnas.1820344116/-/DCSupplemental. different in their scope and aims (8) and vary vastly in their www.pnas.org/cgi/doi/10.1073/pnas.1820344116 PNAS Latest Articles | 1of6 Downloaded by guest on September 24, 2021 the past and for predicting the future evolution of fishing fleets. the number of marine vessels decreased to 3.1 million in 2016, In this paper, we compiled data from various sources to fill in the compared with our estimates which increased to 3.7 million in gaps in the knowledge of global marine fishing fleets, particu- 2015. Similar differences are observed in the unmotorized ma- larly, their history and level of motorization, the separation to rine fleet in 2015/16, estimated from SOFIA 2018 to be under 1 artisanal (both motorized and unmotorized, referred hereafter as million, compared with our estimate of 1.2 million. Our esti- “powered-artisanal” and “unpowered-artisanal”) and industrial mates of the total engine power, however, is only half of that sectors, and their fishing effort. given by previous global studies (SI Appendix, Fig. S13). The motor power of the entire global fishing fleet increased Results quasiexponentially from 1950 to the 1990s followed by a period The Size and Power of the Global Fishing Fleet. The number of of slower growth up to 2015 (Fig. 1C). Until the 1980s, the vessels in the global marine fishing fleet doubled from 1.7 in 1950 to growth of both industrial and powered-artisanal engine power 3.7 million in 2015 (Fig. 1A). This increase is heterogeneous across followed similar trends (Fig. 1 E and F). In the past three de- the globe with a drastic increase in the size of the fishing fleet of cades, however, the growth of industrial fleets has slowed con- Asia (defined hereafter as the countries in East Asia and the Indian siderably, and now the total engine power of the powered- Peninsula and excluding the Middle East, which were grouped in- artisanal sector is equal to that of the industrial. It is important stead with the Maghreb under “Arab World”), only slightly com- to note, however, that the vastly varying definitions of artisanal pensated by a fleet reduction in developed countries, such as fishing globally imply a certain level of uncertainty and overlap. observed in North America and Western Europe in the 1990s. Regionally, the power of European, North American, and The magnitude of changes across the three sectors differs Australian fleets more than doubled from the 1950s to the 1980s, substantially. Although the unpowered-artisanal fleet declined by followed by a drastic reduction in the 2010s (Table 1). Their 0.2 million between 1950 and 2015, the motorized fleet, both share of the global fleet, however, dropped drastically, especially powered-artisanal and industrial, increased more than six times its unpowered-artisanal component. By contrast, the Asian share over the same period (Table 1), accompanied by an increase in of the global fleet and their total engine power have increased the mean engine power (Fig.