Fishing Effort and Associated Catch per Unit Effort for Small-Scale Fisheries in the Mozambique Channel Region: 1950–2016

Dirk Zeller,Angie Coulter,Maria L Deng Palomares,Simon-Luc Noël,Audrey Zhu,Gabriel M S Vianna,Matthew Ansell,Brittany Derrick,Daniel Pauly,Krista Greer

doi:10.3389/fmars.2021.707999

Abstract

The Mozambique Channel region in East Africa has diverse marine ecosystems and serves as a migratory corridor for economically important species. Local and foreign industrial fisheries operate in the Mozambique Channel, but regional small-scale fisheries are the crucially important fisheries that provide food security, livelihoods, and economic opportunities for rural coastal communities. This study reconstructed and investigated trends in the fishing effort and catch per unit effort (CPUE) of small-scale marine fisheries in four Exclusive Economic Zones (EEZ) that constitute the Mozambique Channel, i.e., Union of Comoros, Madagascar, Mayotte, and Mozambique, from 1950 to 2016. Effective fishing effort for small-scale fisheries in the form of fishing capacity in kWdays (i.e., kilowatt days) was derived using the number, length, motorization (engine power) by fishing vessels, as well as an approximate human-powered equivalent for shore-based fishers without vessels, as well as days of fishing per year. Effective small-scale fishing effort in the Mozambique Channel increased by nearly 60 times from just over 386,000 kWdays in 1950 to over 23 million kWdays in 2016. Correspondingly, the overall small-scale CPUE, based on previously and independently reconstructed catch data declined by 91% in the region as a whole, from just under 175 kg⋅kWday–1 in the early 1950s to just over 15 kg⋅kWday–1 in recent years. All four EEZs showed the strongest declines in the small-scale CPUE in the earlier decades, driven by motorization and growth in vessel numbers impacting effective fishing effort. Increased motorization combined with a substantial growth in overall vessel numbers were the drivers of the increasing fishing effort and decreasing CPUE, and clearly suggest that continuing to increase the fishing capacity of small-scale fisheries in the absence of effective and restrictive management actions may exacerbate overexploitation risk.

Highlights

The Mozambique Channel region in East Africa separates Madagascar from the African continent (Figure 1) and is characterized by high marine biodiversity and a variety of ecosystems, including a large proportion of the Indian Ocean’s coral reefs, mangroves, and seagrass beds (Nunes and Ghermandi, 2015)
Overall small-scale fishing effort in the Mozambique Channel region increased nearly 60-fold since 1950. This increase was dominated by growth in fishing effort in Madagascar since the mid-1980s and in Mozambique since the 1990s, the other countries/territories grew in effective effort over the 67-year period considered here (Figure 2A)
We used a data reconstruction approach (Zeller et al, 2016) to refine and update the preliminary fishing effort data of Greer et al (2019a) for small-scale fisheries from 1950 to 2016 in the four inhabited countries or territories that make up the Mozambique Channel region off East Africa (Figure 1)

Summary

Introduction

The Mozambique Channel region in East Africa separates Madagascar from the African continent (Figure 1) and is characterized by high marine biodiversity and a variety of ecosystems, including a large proportion of the Indian Ocean’s coral reefs, mangroves, and seagrass beds (Nunes and Ghermandi, 2015). It is an important corridor for migratory species, such as tuna (Nunes and Ghermandi, 2015). The underrepresentation of small-scale fisheries is a common issue globally, which contributes to the marginalization in socio-economic and political considerations (Pauly, 2006; Schuhbauer and Sumaila, 2016; Teh et al, 2020) as well as in official statistics (Pauly and Charles, 2015; Zeller et al, 2015; Pauly and Zeller, 2016a), despite more recent efforts to begin addressing this issue (FAO, 2015b)

Methods

Results

Conclusion