Updated Statewide Abundance Estimates for the Florida Manatee - FWC/FWRI Technical Report 23 - 2018
Technical Report 23 - 2018
Knowing how many manatees live in Florida is critical for conservation and management of this threatened species. Martin et al. (2015) flew aerial surveys in 2011–2012 and estimated abundance in those years using advanced techniques that incorporated multiple data sources. We flew additional aerial surveys in 2015–2016 to count manatees and again applied advanced statistical techniques to estimate their abundance. We also made several methodological advances over the earlier work, including accounting for how sea state (water surface conditions) and synchronous surfacing behavior affect the availability of manatees to be detected and incorporating all parts of Florida in the area of inference. We estimate that the number of manatees in Florida in 2015–2016 was 8,810 (95% Bayesian credible interval 7,520–10,280), of which 4,810 (3,820–6,010) were on the west coast of Florida and 4,000 (3,240–4,910) were on the east coast. These estimates and associated uncertainty, in addition to being of immediate value to wildlife managers, are essential new data for incorporation into integrated population models and population viability analyses.
CFFW Presentation to the Manatee Forum:
"An Updated Assessment of Manatee Carrying Capacity in the IRL",
IRL Carrying Capacity Assessment-102516
This presentation was made to the attendees at the meeting on the first of the two days October 25/26 of the Manatee Forum at Florida Fish and Wildlife Research Institute (FWC / FWRI) facilities in St. Petersburg FL.
The content includes the latest data with respect to IRL seagrass acreage, local IRL manatee population counts, calculations of the permanent negative impact of uprooting during manatee foraging, calculations of boundary values indicating 3 to 10 acres of seagrass are required per manatee wintering in the IRL, the negative impact of the warm water discharge from the FPL Cape Canaveral Enery Center (CCEC) and the disappearing margin between the diminshed IRL deagrass capacity and increasing wintering manatee population.
CFFW Comments to Support the USFWS Rule Proposal to Upgrade the Manatee to "Threatened"
with an IRL Addendum
This is CFFWs public comment submitted to USFWS supporting the proposed Rule Change to reclassify the manatee as "threatened". This proposed change is the outcome of the assessment conducted by USFWS over the period Sept 2014 to December 2015. This document is a partial rewrite and update to our comments provided in September 2014.
The first few pages of this document provide an Executive Summary of the entire document. The document itself is the CFFW formal submission to USFWS in April 2016 to encourage USFWS to initiate the formal process to reclassify the manatee from "endangered" to "threatened". Ultimately, the data and analyses provided clearly support the status change to "recovered" which is the removal of the manatee from the Endangered Species Act.
Due to the condition of the IRL and the concern about the affect of this on manatee habitat, we also submitted this addendum. Those who have advocated against reclassification have used the IRL condition as an indicator of future threats to the manatee. This argument does not recognize the significance of the seagrass impact that manatees have contributed to the north-central IRL condition. Over the last 5-10 years the number of manatees wintering in the north central IRL has more than doubled to nearly 2,000 animals.
This ever increasing localized herd is the direct result of the 55 year old man made warm water outflow at the power plant location in Brevard. The IRL seagrass to cannot sustain an ever increasing grazing pressure. To help save the IRL, we must eliminate the warm water outflow to return the manatee to its natural migration habits, vacating the north central IRL for the winter months, to reduce the year-round manatee pressure on the seagrass.. The manatee must be reclassified to permit this change.
USFWS / USGS Manatee Core Biological Model - Population Assessment
Status and Threats Analysis for the Florida Manatee (Trichechus manatus latirostris), 2012
This is the USFWS / USGS "Core Biological Modeling" Report prepared in 2012
The endangered West Indian manatee (Trichechus manatus), especially the Florida subspecies (T. m. latirostris), has been the focus of conservation efforts and extensive research since its listing under the Endangered Species Act. On the basis of the best information available as of December 2012, the threats facing the Florida manatee were determined to be less severe than previously thought, either because the conservation efforts have been successful, or because our knowledge of the demographic effects of those threats is increased, or both. Using the manatee Core Biological Model, we estimated the probability of the Florida manatee population on either the Atlantic or Gulf coast falling below 500 adults in the next 150 years to be 0.92 percent. The primary threats remain watercraft-related mortality and long-term loss of warm-water habitat. Since 2009, however, there have been a number of unusual events that have not yet been incorporated into this analysis, including several severely cold winters, a severe red-tide die off, and substantial loss of seagrass habitat in Brevard County, Fla. Further, the version of the Core Biological Model used in 2012 makes a number of assumptions that are under investigation. A revision of the Core Biological Model and an update of this quantitative threats analysis are underway as of 2015.
CFFW Comments to USFWS Supporting Upgrading the Manatee to "Recovered"
The first few pages of this document provide an Executive Summary of the entire document. The document itself is the CFFW formal submission to USFWS in September 2014 to encourage USFWS to initiate the formal process to reclassify the manatee from "endangered" to "threatened". Ultimately, the data and analyses provided clearly support the status change to "recovered" which is the removal of the manatee from the Endangered Species Act.
Our arguments are organized into sections which include sections that directly address each of the factors identified in the ESA that are used to determine classification:
Manatee Abundance and Survivability
Manatee Carrying Capacity and Optimum Sustainable Population
Manatee Risk Management
Manatee Potential Biological Removal
Rebuttal of Common Arguments in Opposition to Reclassification