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

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.

The Contribution of Marine Fisheries to Socio-economic Development in Tanzania Mainland: Reflections on the Blue Economy Concept from Selected Coastal Villages

“…This clearly indicates that increasing fishing capacity in the absence of effective and restrictive management actions may intensify the risk of overexploitation. These findings concur with Zeller et al (2021) who reported that CPUE declined by 91% across the Mozambique Channel region as a result of motorization and growth in vessel numbers during the period 1950-2016. Also, Silas et al (2020;2021) observed that artisanal fishing vessels, which are dominant in the nearshores of coastal areas in Tanzania, have resulted in overexploitation of fisheries resources as signified by decreasing CPUE.…”

Fisheries yields and species declines in coral reefs

“…Many countries were sampled insufficiently to determine the national-level status of fishing. Yet, there appears to be a propensity to reduce fish populations in nearshore coral reefs in this region to about one half the stock values where MMSY is achieved , Zeller et al 2021. The patterns observed here and from models indicate that over-fishing is pervasive even in the region's many low compliance marine reserves (McClanahan et al 2015.…”

Economic Study of Resource Management Silver Pomfret (Pampus argentus) and Barramundi (Lates calcarifer) in Cirebon District, West Java - Indonesia

“…Catch per unit effort is a basic fisheries science often used as a first-order evaluation of board trends in likely relative abundance or relative biomass trends over time of the underlying fish stocks [11][12][13]. While CPUE has its limitations, it can be useful in long term trend monitoring of a fishery, particularly where more detailed data and stock assessments do not exist (Stamatopoulos, 2022) and open or semi open access fisheries predominate, i.e., where restrictive fisheries management actions may be absent or ineffective [13]. Based on the catch per unit effort analysis results for Silver pomfret, it was found the highest CPUE value was the payang gear.…”