Ines Agosto

Document Type

Internship Report

Publication Date

Spring 2019


The Miami-Dade Manatee Protection Plan was implemented namely to reduce the number of manatee mortalities by regulating where non-single-family home boat slips are authorized and ensure long-term protection for manatees in Dade county. Since its implementation in 1995, manatee mortality rates have generally increased in Miami Dade County. Stakeholders have argued that the speed restrictions and the regulations imposed on slip construction are too stringent and leave boats with insufficient access to dockage while other stakeholder have also claimed that the Manatee Protection Plan has not worked to decrease manatee mortalities. However, managers and scientists believe that the increase in mortalities is due to a combination of lack of compliance of speed zones and the siting of boating facilities in areas that are frequently used by manatees. The goal of this project was to utilize Geographical Information Systems to evaluate trends in manatee sightings and mortalities in Miami Dade County and the Miami River, as well as to document the increase and location of marine operating facilities in the Miami River. In addition, vessel traffic at the mouth of the Miami River was evaluated employing Dr. Jay G’s methodology in his 2009 study on recreational boating activity in Miami Dade County. Results indicated that the location of manatee carcasses were statistically significant between three different decades but not by cause of death. In addition, the highest density of mortalities and sightings occurred within the Miami Dade County line and north of the Rickenbacker Causeway, areas associated with extensive water-related recreational activities. Both sightings and carcass data confirmed historical documentation, specifically that manatees tend to congregate upstream in the Miami River. The vessel traffic at the entrance of Miami River agreed with Gorzelany’s results, indicating that small recreational vessels are the vessels that are the most noncompliant to the idle speed limit. Lastly, the results noted the emergence of more marine facilities and boat slips within the river and in areas where manatees are found in a review of Marine Operating Permit data from 2007 and 2017(or 18). This suggests that manatees are not only vulnerable to non compliant speeding vessels but to areas with high levels of boating activity.


Department: MBE

MPS Track: TME

Location: Miami Dade County

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