Duval, Clay, & St. Johns counties 1993-1994 Manatee Distribution Survey Theoretical Flight Path

Aerial distribution surveys are used by marine mammal biologists from FWC and other agencies to determine the seasonal distribution of manatees. Most surveys are conducted from small, four-seat, high-winged airplanes (Cessna 172 or 182) flying at a height of 500-1000 ft at a speed of 70-90 kts. Small helicopters may be used instead of fixed wing aircraft in urban areas or where waters are particularly opaque and hovering may be required. Surveys are flown along a standardized, theoretical flight route, which was designed to cover all likely manatee habitats in the study area. This "theoretical flight path" indicates the area that was covered during each survey, but it may not be the actual flight route flown on every survey. GPS tracklines recorded during surveys may be available for some flights. The survey area includes the western half of Duval County, with emphasis on the many tributaries of the St. Johns River. It extended south into St. Johns and Clay counties to Black Creek. The survey route included the Trout, Ribault, Arlington, Ceder, and Ortega rivers; Pottsburg, Black, Durbin, and Julington creeks; Doctor’s lake and portions of the St. Johns River between tributaries from the Trout River to Green Cove Springs.来自佛罗里达鱼类与野生动物保护委员会（FWC）及其他机构的海洋哺乳动物生物学家，会通过航空分布调查确定海牛的季节性分布范围。绝大多数调查在小型四座高翼飞机（塞斯纳172或182）上开展，飞行高度为500至1000英尺，飞行速度为70至90节。在城市区域或水体透明度极低、需要悬停作业的场景中，可使用小型直升机替代固定翼飞机。所有调查均沿标准化的理论航线飞行，该航线的设计初衷是覆盖研究区域内所有潜在的海牛栖息地。这条"理论飞行路径"标注了每次调查所覆盖的区域，但实际执行时未必完全遵循该航线。部分航班会留存调查期间记录的GPS航迹数据。调查区域涵盖杜瓦尔县的西部区域，重点覆盖圣约翰斯河（St. Johns River）的众多支流；该区域向南延伸至圣约翰斯县与克莱县境内的布莱克溪。调查航线途经特劳特河、里博特河、阿灵顿河、锡达河与奥尔特加河；波茨堡溪、布莱克溪、德宾溪及朱林顿溪；多克托湖，以及圣约翰斯河从特劳特河支流至格林科夫斯普林斯之间的河段。