Small pieces of notched pottery at lowland Maya archaeological sites served as sinkers or weights (pesas) for fishing nets and lines. More than 1400 of these artifacts recovered from six sites in the central Petén lakes region dated to the Preclassic, Classic, and Postclassic/Contact periods. Thirteen variables of the sinkers were analyzed, including provenience, dimensions, pottery type, and shape, with comparisons among sites and individual structures within sites—including locations of probable decomposed fishing nets. The weights of these artifacts declined dramatically between Preclassic and Classic times, and then less abruptly in the Postclassic, when they began to exhibit signs of a smaller range of dimensions and use of specially formed pellets. The decline in weight suggests capture of smaller fish, and may reveal changes in water quality, fishing strategies, or “fishing down the food web.” 1. Introduction to Lowland Maya Fish and Fishing The Lowland Setting Ancient Mesoamerican Art and Ritual Colonial History and Ethnography 2. The Petén Environment, Archaeology, and Fishes The Central Petén Lakes’ Environment Archaeology and Occupational History of the Lake Basins Freshwater Fishes of Central Petén Fishing Today 3. Fishing Nets and Sinkers Nets Sinkers (Pesas) Characterizing Petén Methods 4. Petén Lakes’ Preclassic and Classic Sinkers Preclassic-Period Sinkers Classic-Period Sinkers 5. Postclassic Contexts and Sinkers Postclassic and Later Sinkers Macanché Island Zacpetén Ixlú Lakes Quexil and Petenxil Tayasal Nixtun-Ch'ich' 6. Fiber-Working and Net-Making 7. Petén Pesas in Broader Context Comparisons of Weight Color Dimensions Classic and Postclassic Comparisons Chronological and Geographical Variations Technology and Economy Why Declining Weights? Archaeological Data on Fish Consumption 8. Discussion and Conclusions