He threw changeups, fastballs, sinkers, curveballs, cut fastballs, and sliders. Split-shot sinkers are small and round with a split cutting halfway through the sinker. There are a variety of lures to choose from including sinkers and bobbers. However the use of fish-hooks, harpoons, and nets and sinkers was fairly widespread. In trolling, swivel sinkers are indispensable. They made jewelry, weights, and sinkers by grinding stone. Purpose designed sinkers exist to control the trolling depth on freshwater lakes. For example, it can replace lead as a dense material in fishing sinkers. Horizontal movement also occurs when sinkers are thrown. The pitching is simple&colon; curve balls, fast balls, off-speed pitches, and sinkers. Environmental concerns surround the usage of lead and other materials in fishing sinkers. Lead based fishing sinkers are banned in all of US and Canadian National Parks. These sinkers are desirable on rock or debris covered substrates. The columella was also used to make plummets or sinkers. Anthropogenic lead includes lead from shot and sinkers.