An Ecosystem Services Perspective for the Oceanic Eastern Tropical Pacific: Commercial Fisheries, Carbon Storage, Recreational Fishing, and Biodiversity

Summer L Martin,Lisa T Ballance,Theodore Groves

doi:10.3389/fmars.2016.00050

Abstract

The ocean provides ecosystem services (ES) that support humanity. Traditional single-issue management largely failed to protect the full suite of ES. Ecosystem-based management (EBM) promotes resilient social-ecological systems that provide ES. To implement EBM, an ES approach is useful: 1) characterize major ES provided (magnitude, geographic extent, monetary value, trends, and stakeholders), 2) identify trade-offs, 3) determine desired outcomes, and 4) manage anthropogenic activities accordingly. Here we apply the ES approach (steps 1-2) to an open ocean ecosystem, the eastern tropical Pacific (ETP), an area of 21 million km2 that includes waters of 12 nations and the oceanic commons, using 35 years (1975-2010) of fisheries and economic data, and 20 years (1986-2006) of ship-based survey data. We examined commercial fisheries, carbon storage, biodiversity, and recreational fishing as the major provisioning, regulating, supporting, and cultural ES, respectively. Average catch value (using U.S. import prices for fish) for the 10 most commercially fished species was $2.7 billion yr-1. The value of carbon export to the deep ocean was $12.9 billion yr-1 (using average European carbon market prices). For two fisheries-depleted dolphin populations, the potential value of rebuilding carbon stores was $1.6 million (cumulative); for exploited fish stocks it was also $1.6 million (an estimated reduction of 544,000 mt). Sport fishing expenditures totaled $1.2 billion yr-1, from studies of three popular destinations. These initial, conservative estimates do not represent a complete summary of ETP ES values. We produced species richness maps for cetaceans, seabirds, and ichthyoplankton, and a sightings density map for marine turtles. Over 1/3 of cetacean, seabird, and marine turtle species occur in the ETP, and diversity (or density) hotspots are widespread. This study fills several gaps in the assessment of marine and coastal ES by focusing on an oceanic habitat, utilizing long-term datasets, mapping the spatial distribution of ecological components, and concentrating on an area beyond Europe and the USA. Our results improve our understanding of ETP ES, highlight their variety, and offer a new perspective for a fisheries-dominated system. This study sets the stage for further analyses of trade-offs, which can inform decisions about resource management and biodiversity conservation.

Highlights

The ocean provides ecosystem services (ES) that are critical to the survival and well-being of humanity (Ehrlich and Ehrlich, 1981; Costanza et al, 1997; Daily et al, 1997; Costanza, 1999)
We define the oceanic eastern tropical Pacific (ETP) as the area seaward of the continental shelf, from the Americas west to approximately 150◦ longitude, and from the U.S.-Mexico border south to central Peru (Figure 1). It has an area of 21 million km2, includes waters of 12 nations and the oceanic commons, and roughly corresponds to the area managed by two regional fishery management bodies: the Inter-American Tropical Tuna Commission (IATTC) and the Agreement on the International Dolphin Conservation Program
Our study provides a different perspective—one that is central to Ecosystem-based management (EBM)—for an oceanic ecosystem with historically productive commercial fisheries (Figure 6)

Summary

Introduction

The ocean provides ecosystem services (ES) that are critical to the survival and well-being of humanity (Ehrlich and Ehrlich, 1981; Costanza et al, 1997; Daily et al, 1997; Costanza, 1999). Marine organisms, most notably phytoplankton, account for nearly 50% of global primary production (Field et al, 1998)—this supports marine ecosystems by generating oxygen and particulate organic carbon (POC) for animals to consume. This process initiates the biological pump, which transports a fraction of POC from the surface to the deep ocean, where it is sequestered on timescales of thousands to millions of years (Ducklow et al, 2001; Henson et al, 2012). The economic value of all marine ES is estimated at $50 trillion (USD) yr−1 (Costanza et al, 2014)

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