Some artisanal fleets in West Africa have grown so much in terms of number of boats, vessel size and capacity, and the aggregate engine power that they deploy that they have become comparable to the smaller industrial fleets operating in the region.

A new study by the Sea Around Us project reveals that, in the past 60 years, total artisanal fishing effort in the waters that extend from the coast of Morocco to the coast of Angola has increased by 10-fold.

Given that industrial fleets –mostly from the EU and China- have been taking most of their fish, artisanal fisheries in the area have been forced to build bigger boats and go fish further. Yet, this intensified effort is not yielding larger catches for them.

“Artisanal fisheries have become less efficient, both over time and compared to their industrial counterparts,” said Dyhia Belhabib, lead author of the study and Fisheries Program Manager at Ecotrust Canada, who conducted this research while working for the Sea Around Us at the University of British Columbia’s Institute for the Oceans and Fisheries.

Belhabib reached this conclusion after having developed, together with co-authors Daniel Pauly and Krista Greer, a new standardized metric that allowed for comparisons between the fishing effort of different artisanal vessels and that of industrial vessels. “We transformed fishing effort into kW/hours. We had to assemble data on the number of boats, their length, the number of days that they operate, their gear type; based on that information, we inferred engine power. Whenever there was a boat that was not motorized, we converted manpower into kW/hours,” Belhabib explained.

“Simply put,” Krista Greer added, “fishing effort is the product of the capacity of a vessel to do work (energy) and the rate at which work is done (power or days fished).” For artisanal fisheries in West Africa, this effort increased from less than 400 million kWdays in the 1950s to over 4,500 million kWdays in the 2000s. This is four times higher than the amount of energy spent by the industrial sector.

“This is very surprising because small-scale fisheries are usually perceived as small but in terms of engine power they are big,” said Daniel Pauly.

However, having turned their ‘pirogues’ into larger, motorized vessels that can reach up to 30 metres in length, carry some 40 fishermen and stay for 10 days out at the sea is not paying off for artisanal fleets. According to the study published in Conservation Letters, their catch per effort declined from 5 kg of fish per kWdays in the 1950s to 1.5 kg per kWdays in the 2000s. This is 11 times lower than industrial catch per- effort in the area.

Pauly explained that diminished catches are also a result of overexploitation carried out by foreign industrial fleets. “This provides evidence that there is a decline in the biomass of the resources,” he said, pointing out that the new measure is useful to identify the status of stocks in data-poor contexts.

Looking at the silver lining, the researchers said that their result makes the case for pushing policymakers to support artisanal fisheries while limiting industrial fleets operating in West Africa. “The artisanal sector is better in terms of the ecosystem and social implications. It catches less fish than the industrial sector while providing more jobs. Industrial fleets, on the other hand, catch enormous amounts of fish while taking food and opportunities away, since most of them fail to land their catch in the region and to employ locals,” Belhabib said.

The study “Trends in Industrial and Artisanal Catch Per Effort in West African Fisheries” was published last week in Conservation Letters.

To schedule interviews with the authors please contact Valentina Ruiz Leotaud v.ruizleotaud@oceans.ubc.ca | 604.8273164