Management effectiveness of large pelagic fisheries in the high seas

Abstract

Large pelagic fishes are assessed and managed by tuna Regional Fisheries Management Organizations (tRFMOs). These organizations have been criticized for not meeting conservation objectives, which may relate to aspects of governance and management. No previous studies have systematically evaluated why management performance differs among tRFMOs and among stocks within each tRFMO. In this study, we collected data on the nature of research, management, enforcement and socioeconomics of management systems in the five principal tRFMOs of the world's oceans. We quantified influences of economic and fishery‐related factors on these management characteristics and examined how these factors vary among tRFMOs. We found that tRFMOs with a greater number of member countries, a greater economic dependency on tuna resources, a lower mean per capita gross domestic product, a greater number of fishing vessels and smaller vessels were associated with less intensive research, management and enforcement in these tuna fisheries. We also quantified the influence of specific management attributes and of biological, economic and fishery‐related factors on the trends and current status of large pelagic fish stocks in these regions. The most important factors correlated with trends and current stock status were external to the management systems, and included stock size, age at maturity, ex‐vessel price and economic dependency of countries on tuna fisheries. To improve the overall status of large pelagic fish stocks in the global high seas, more intensive data collection, research and management are needed in certain areas, especially in the Indian Ocean, and for certain stocks, especially non‐target species.

Effective fisheries management instrumental in improving fish stock status

“…Given the subsidies that are in place in several countries for tuna fisheries (24), we would expect fishing pressure to be higher than the true bionomic equilibrium. More detailed analysis of tuna fisheries (12) has suggested that the status of tuna stocks is primarily influenced by factors other than the fisheries management system, including life-history and market factors.…”

“…Countries differed greatly in the intensity of fisheries management, and this study showed that expert opinion on stock status was closely related to the intensity of fisheries management. Pons et al (12) conducted a similar survey of international tuna management organizations, and further data for 36 additional countries have recently been collected, yielding, in total, data for 1,063 stocks from 70 countries or regional fisheries management organizations (RFMOs). We have an extensive data set of how fisheries are managed from all major fishing regions of the world (as of 2016), but lack stock abundance and exploitation rate estimates for most fisheries in South and Southeast Asia (Fig.…”

The economics of fishing the high seas

“…Highly migratory species such as tuna and sharks that move between the high seas and countries’ jurisdictional waters [exclusive economic zones (EEZs)] tend to be intensely fished and overexploited ( 4 ). Although the International Seafood Sustainability Foundation indicates that 57% of managed tuna stocks are considered to be at a healthy level of abundance, 13% are overfished ( 5 ), and even those that are not overfished show slight declines in biomass over time ( 6 ) and may benefit from increases in biomass. Oceanic sharks, of which 44% are threatened ( 7 ), spend a great deal of time in the high seas, where shark fishing is largely unregulated and unmonitored ( 8 ).…”

Spatiotemporal Variability of Target-Species in Tuna and Tuna-Like Fishing in Brazil

“…Marine species presenting wide oceanic distribution such as tuna, swordfish and shark species, are the catch-target in several countries (Hobday et al, 2017;Pons et al, 2018). The meat of these species is quite appreciated and has high commercial value in the international market, mainly in the USA, Europe and Asia (Arrizabalaga et al, 2011;Guillotreau et al, 2017).…”