Stock assessment of Prochilodus nigricans (Actinopterygii: Characiformes: Prochilodontidae) using two distinct algorithms, in the context of a small-scale Amazonian fishery

Michel Catarino,Freitas Cec,James Kahn

doi:10.3750/aiep/02623

Abstract

Background. Despite the importance of inland fishery, assessments of exploited inland stocks have relied on data-deficient databases, mainly in developing countries. In this paper, we employed two distinct analytical methods to evaluate the stock status of Prochilodus nigricans Spix et Agassiz, 1829, the most important fish in the Amazonian freshwater landings. In this study, we intended to test the sustainability of small-scale fisheries comparing two different methods. Materials and methods. The population dynamic of P. nigricans was studied using length and weight data for fish caught in Manacapuru Lake and the lower stretch of the Solimões River. Estimates of maximum sustainable yield and corresponding fishing mortality for 2012 and 2013, using Beverton–Holt curve, indicated an overfishing status for both years. At the same region, fishers were interviewed and their knowledge on the P. nigricans stock status was assessed using a stock assessment methodology based on fishers’ knowledge, known as ParFish. Results. Both yield per recruit curves employed to assess the stock status of P. nigricans in 2012 and 2013 and ParFish approach indicate an overfishing status, but ParFish also found a high uncertainty level around 47%. Conclusion. The use of ParFish algorithm and traditional knowledge can provide qualitatively similar results to conventional models, such as the Beverton–Holt approach. The ParFish approach shows the advantage including confidence intervals to its estimates.

Highlights

Despite the importance of inland fishery, assessments of exploited inland stocks have relied on datadeficient databases, mainly in developing countries
We conducted an assessment using the Participatory Fisheries Stock Assessment (ParFish) software, based on the fishers’ traditional knowledge. This dual approach was developed to reach the secondary objective of evaluating ParFish as a tool to perform a stock assessment in inland small-scale fisheries by the comparison between the estimated parameters
The population parameters of maximum theoretical length (L∞), natural mortality (M) and total mortality (Z) were similar to those found by previous studies for Prochilodus nigricans

Summary

Background

Despite the importance of inland fishery, assessments of exploited inland stocks have relied on datadeficient databases, mainly in developing countries. We employed two distinct analytical methods to evaluate the stock status of Prochilodus nigricans Spix et Agassiz, 1829, the most important fish in the Amazonian freshwater landings. We intended to test the sustainability of small-scale fisheries comparing two different methods. Estimates of maximum sustainable yield and corresponding fishing mortality for 2012 and 2013, using Beverton–Holt curve, indicated an overfishing status for both years. Both yield per recruit curves employed to assess the stock status of P. nigricans in 2012 and 2013 and ParFish approach indicate an overfishing status, but ParFish found a high uncertainty level around 47%. The use of ParFish algorithm and traditional knowledge can provide qualitatively similar results to conventional models, such as the Beverton–Holt approach.

INTRODUCTION

MATERIALS AND METHODS

DISCUSSION