The Hydrological Cycle of the Lower Amazon in Brazil Determines the Variation in Local Fishing Patterns

Fishery catches on the Lower Amazon River were analyzed in relation to the hydrological cycle, temporal shifts in fishing effort, and the use of nets or lines in lakes and rivers. The study was based on a temporal series of catch data collected between January 1993 and June 2011. The variables analyzed were the total catch, use of gillnets or lines, the environment targeted (lakes or rivers), and fishing effort. Temporal trends in the data series were analyzed using the Mann-Kendall test. An Analysis of Covariance (ANCOVA) was used to evaluate whether gillnet and line catches had independent effects on the catch data. Duncan's test was applied to identify the groups (months) of means that were significantly different from each other. The majority of the catch landings were taken with gillnets (98.65%) in a lake environment (64.98%). The temporal series showed a significant decline over time in the gillnet catches from both lakes and rivers, as well as in fishing effort. The influence of the annual flood cycle was reflected in the catches and the flood pulse regulated fishing productivity patterns in the region. The fishers who adapt their activities to this flood pulse have good traditional knowledge of the environment. The results of the study also indicated that any changes in this dynamic system may impact traditional local fisheries and affect the economic wellbeing of local fisher populations.

Automated summary

The study analyzed fishery catches on the Lower Amazon River with regards to the hydrological cycle, temporal shifts in fishing effort, and the use of nets or lines in lakes and rivers. It found that the majority of catch landings were taken with gillnets in a lake environment. There was a significant decline in gillnet catches from both lakes and rivers over time, as well as fishing effort. The annual flood cycle had an impact on fishing productivity patterns in the region.