Toxicants, such as heavy metals and dioxins, may affect fish productivity. Alterations in water flow can prevent successful spawning of fish. Ditching and draining wetlands for farming and forestry has caused loss of habitat and sedimentation of streams. Dams and stream culverts. These structures may block fish migration and alter natural water flow necessary for successful fish reproduction.
Farms contribute nutrients, sediment and chemicals.
City streets and parking lots contribute toxic organics, heavy metals, and oil. Industrial and Municipal Waste. Discharges often contain nutrients, bacteria, or toxic chemicals. Recreational fishermen compete with commercial fishermen for a share of an already stressed resource. Development, much of it along the coast, causes loss of critical habitat and creates greater need for waste disposal.