Declínio de espécies ícticas de baixo valor comercial na percepção de pescadores e comerciantes do Baixo Amazonas

Abstract

The Amazonian ichthyofauna is diverse, but local fishing focuses on a few species, including those of low commercial value susceptible to overfishing. This study sought to identify, in the perception of fishermen and traders from Santarém-PA, in the Lower Amazon, which species of low commercial value are decreasing in quantity in landings and the possible reasons. The research was carried out between April and July 2024 in fairs and markets, through interviews using a semi-structured questionnaire with fishermen and traders recognized by their peers, using the “Snowball” method. The data were organized in spreadsheets, analyzed with descriptive statistics and compared to historical series of landings. Chi-square tests, adjusted residual analysis (via Past) and Pearson correlations between years and catch volumes (via Jamovi) were applied to the most cited species in decline. The causes of the disappearance of species and the suggestions of fishermen were represented in Sankey diagrams. Differences in perceptions between fishermen and traders about species of low commercial value were analyzed with the Kruskal-Wallis test, after checking normality by the Shapiro-Wilk test, using the R software. To investigate the relationship between the decline of ethnospecies of low commercial value and ecological or commercial factors, an index was developed based on annual biomass, integrating regression coefficient, R² and p-value. Forty-seven interviews were conducted with fishermen and 57 with traders, both mostly men, with an average age over 50 years and more than three decades of experience in fishing activity. Thirty-eight ethnospecies cited by fishermen and 37 by traders as regular components of fishing and marketing were identified. Fishermen perceive a reduction in the capture of fish of low commercial value in recent years. Among the most cited (62.4%) are aracus, hake, cigars, acarás, aruanã, jaraquis, tamoatá, traíra, matrinxã and curimatã. The comparison with landing data from the periods 2001–2004 and 2011–2020 revealed statistically significant differences, indicating relevant variations in abundances over time. Correlation analyses revealed a significant decline in the abundances of hake, aracu, acará, matrinxã and jaraqui, with negative and high correlation coefficients throughout the landing years. This decline is attributed to fishing pressure, impacts of large-scale enterprises, environmental degradation and lack of monitoring, especially since 2004. In addition, intense droughts, small floods and cold snaps were mentioned as associated phenomena. The quantity of kg sold annually was the variable most explanatory of the observed decline. To reverse this situation, fishermen suggested greater government control over fishing, including strict monitoring, environmental education, improved community management and greater compliance with fishing regulations. They also highlighted the creation or strengthening of public policies and the need for greater participation of fishermen in decision-making processes. The study highlights that combining local and scientific knowledge, with the support of public policies, is essential for sustainable fishing and the conservation of fish stocks.