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Thesis - NSU Access Only
M.S. Marine Biology
Second Degree Name
M.S. Coastal Zone Management
Edward O. Keith
Daniel K. Odell
Curtis M. Burney
Florida manatees (Trichechus manatus latirostris) are known to winter in the warm coastal waters of South Florida and are especially attracted to the heated effluent from power plants. A portion of the Intracoastal Waterway within John U. Lloyd Beach State Park attracts manatees to its shallow mangrove-lined canals and warm outpourings from the Port Everglades power plant. Heavy boat traffic and the danger of manatee-boat collisions has resulted in no-entry zone sanctuaries and seasonal and year-round slow and idle speed zones, which have been created in coastal areas throughout Florida where manatees are frequently sighted. Unfortunately, even with these zones in place, boat strikes are still a problem in counties along Florida's coast.
This study was conducted to obtain a characterization of speed zone compliance in speed zones around the Port Everglades power plant, Broward County, Florida. Objectives of the study were as follows: 1) Determine boater compliance with manatee speed zones based on miles per hour values; 2) Examine boat size, boat type, day of week, and time of day for effects on compliance and behavior; 3) Examine the effects of the presence of law enforcement vessels on compliance and behavior; and 4) Relate these results to the Florida Manatee Management Plan.
The criterion by which boat speed is most often measured relates to wake size rather than a numerical value, and most regulatory signs in current manatee speed zones reflect this, using phrases such as ‘Slow Speed, Minimum Wake’ or ‘Idle Speed, No Wake’. To survey the speed of boats around Port Everglades, these speed definitions were converted to equivalent ranges of miles per hour values, providing a comparison for the speed of passing boats measured in miles per hour by a laser speed gun.
To obtain a survey of boater behavior and test the effectiveness of the posted signs regulating boat speed in the area around the Port Everglades power plant, the speed of passing vessels was measured and recorded in miles per hour using Falcon Marine and Bushnell Speedster radar speed guns. Vessel speed was recorded from aboard a research vessel and from a position on land, situated so that the target vessel was within the range of the laser speed gun with an angle of incidence is 10° or less. Under these conditions the laser speed gun could accurately measure the speed of passing boats.
Measures of boat speed in miles per hour obtained in the field were then compared to the ranges of speed in miles per hour that represent Slow and Idle speeds for this study. Of all boats surveyed, 23% were traveling at technically noncompliant speeds and 46% were traveling at blatantly noncompliant speeds. Data were grouped by boat type, boat size, day of week, time of day, and presence of law enforcement, and statistically analyzed using Generalized Estimating Equations. Boat type, day of the week, and time of day did not significantly affect boat speed. However, speed was significantly influenced by boat size, and it was also correlated with the presence of law enforcement.
Boats tended to go faster as size decreased. Speed decreased at an average of 0.36 miles per hour with each increasing boat size category, with a standard variance of 0.13 miles per hour. Vessels observed during this study which fell into the smallest size category, less than 12 feet long, traveled at a mean speed of 13.69 miles per hour with a standard variance of 5.46 miles per hour. Within the miles per hour standards this study used for estimation of Slow Speed, this is a blatant violation of vessel speed regulations in the area.
Presence of law enforcement was found to be significantly correlated with boat speed. Surprisingly, observations during this study showed an increase in vessel speed when law enforcement was present in the area. Speed increased at an average of 1.75 miles per hour with the presence of law enforcement, with a standard variance of 0.36 miles per hour. This could possibly be due to the fact that law enforcement vessels were more often visibly present on weekend days, and on these days boats also tended to go faster.
The primary findings of this study included boater noncompliance rates of 23% committing technical violations and 46% committing blatant violations when compared to a miles per hour estimation of current regulation speed categories, and identification of day of week and presence of law enforcement as the factors correlated with boat speed.
Melody J. Fischer. 2008. Boater Compliance with Florida Manatee (Trichechus manatus latirostris) Speed Zones in Port Everglades, Broward County, FLorida. Master's thesis. Nova Southeastern University. Retrieved from NSUWorks, Oceanographic Center. (254)