News

Thank you for the opportunity to comment on the revised critical habitat designation. We commend the U.S. Fish and Wildlife Service for its significant progress in refining and updating designated critical habitat for the Florida manatee. This refined approach demonstrates a commitment to protecting manatees by preserving essential habitats that support their survival and recovery.

However, due to serious escalating risks and threats to manatees from sea level rise and degraded water quality, it is our scientifically based opinion that the proposed critical habitat is insufficient. In our comment, we outline significant threats to proposed critical habitat areas. We identify regions that have experienced substantial losses of submerged aquatic vegetation (SAV) over the past decade, as well as the anticipated loss of warm-water habitats over the next 30 years, which could critically affect manatee survival.

Based on these threats, we recommend increasing the distances from warm-water refuges to 50 kilometers and have identified additional areas that should be included in critical habitat designation based on warm-water access, essential travel corridors and available forage.

Threat to manatees: SAV availability

During the wintertime, manatees gather at warm-water refuges in large numbers and limit their travel to nearby areas of submerged aquatic vegetation. Based on previous studies, the proposed critical habitat revision has designated natural warm-water refuges with reliable thermal quality or established manatee use each year and associated foraging areas (i.e., areas that support submerged, emergent, or floating aquatic vegetation) within 18.6 mi/30km of said refuge as critical habitat (paper sources, page 24). In the proposed revision, the Service evaluated seagrass datasets ranging from 1970 to 2022 from multiple agencies to delineate areas within 18.6mi/ 30km of warm water sources ‘have the ability to support forage materials for manatees’ (pg.36 RPCH).

Our concerns with this rationale are the following:
While an 18.6 mile/30 km distance could be sufficient if submerged aquatic vegetation (SAV) were abundant and all stressors to SAV recovery were fully mitigated, the proposal lacks essential details on how forage availability was assessed. It only states that the designated habitat has the potential to support forage, without addressing the current state of forage.

Discrepancies exist in the data used to determine seagrass coverage. For example, the NOAA 2022 dataset cited in the proposal shows seagrass availability in the Indian River Lagoon within proposed Unit FL-10 based on 2015 data, while the Florida Fish and Wildlife Conservation Commission (FWC) data from 2022 shows little to no available forage in the proposed Unit FL-10 (Figure 1). More recent datasets exist for seagrass coverage in the Indian River Lagoon, and likely other areas of the state as well. The Service references datasets spanning 1970 to 2022. The Statewide Ecosystem Assessment of Coastal Aquatic Resources (SEACAR) Data Discovery database contains a seagrass coverage dataset from 2024, which also shows very little seagrass coverage within the FL-10 critical habitat unit (Figure 1).

Martin et al. (2015) estimated that 70% of the east coast manatee population were in Brevard County during a coast-wide survey in March 2012. Therefore, the lack of forage in the proposed designated critical habitat may not be enough to support the energetic needs of wintering manatees.

Further, many of the proposed critical habitat areas have been adversely impacted by the threats outlined in the special management considerations or protections portion of the proposal. These environmental factors have significantly reduced available SAV and hampered recovery efforts. Storm surges from hurricanes, including recent storms on Florida’s west coast, have caused saltwater intrusion, resulting in the wilting and death of freshwater SAV (Liu et al., 2019). Eutrophication caused by improperly treated sewage, leaking septic systems, fertilizers, and stormwater runoff has led to frequent harmful algal blooms. These blooms have resulted in the loss of over 90% of seagrass biomass in the Indian River Lagoon. It is predicted that the coastal U.S. will experience an increased risk and frequency of coastal storms in the coming years, fueled by climate change (Balaguru et al., 2023). Following Hurricane Irma in 2017, seagrass coverage declined by over 1200 hectares across six estuaries in southwest Florida (Tomasko et al., 2020). Areas with the largest losses following the storm were those where seagrass coverage had declined in previous years, indicating that the effects of the hurricane may have been intensified in previously impacted areas. In Fall 2024, hurricanes Milton (Cat.3) and Helene (Cat.4) made landfall within one month of each other on Florida’s Gulf Coast. After the storms, King’s Bay experienced significant vegetation loss due to high turbidity and storm surge (personal communication, Sea and Shoreline).

The proposal states the abovementioned concerns but lacks a clear rationale for how the quantity and quality of SAV within designated critical habitat will meet the wintertime energetic needs of the current estimated manatee population of 8,350-11,730 animals (Gowan et al., 2023).

Additionally, it does not address how climate change and other environmental stressors may affect SAV availability. Without a clear methodology to assess current and future forage availability, it is unlikely these areas can sustain manatee populations within the 18.6-mile (30-km) limit from a warm water source. Areas proposed as critical habitat that have sustained substantial SAV loss in the past ten years are discussed below.

State of forage in manatee habitats in the last decade

Indian River Lagoon

The Indian River Lagoon has suffered significant losses of SAV between 2009-present. Since 2011, approximately 58% of the seagrass acreage has been lost and the density of seagrass in the remaining areas has decreased from an average of about 20% to about 4% due primarily to reduced light penetration as a result of protracted and intense phytoplankton blooms (Morris et al. 2022). These blooms have resulted in the current loss of over 90% of seagrass biomass in the Indian River Lagoon. Martin et al. (2015) estimated that 70% of the east coast manatee population were in Brevard County during a coast-wide survey in March 2012. Therefore, the lack of forage in the proposed designated critical habitat will not support the energetic needs of wintering manatees.

UME in 2013 and 2020

An estimated 47,000 acres (60%) of seagrass was lost during 2009–2012 between Ponce Inlet, in Volusia County, and Fort Pierce Inlet, in St. Lucie County, covering most of the IRL (Lapointe et al., 2015, 2020; Morris et al., 2018).

In 2013, the Working Group on Marine Mammal Unusual Mortality Events declared an unusual mortality event (UME) following 111 manatee deaths in the Indian River Lagoon (IRL) from an unknown cause. The UME coincided with a major loss of seagrass in the IRL due to non-toxic phytoplankton blooms, leading to an ecosystem shift to macroalgal dominance. The 2013 UME was linked to a lethal clostridial infection triggered by a shift to a macroalgal diet. Clostridium bacteria, normally present in the manatee gut, can multiply and release toxins when the diet shifts to low-fiber macroalgae, causing rapid and fatal inflammation (Landsberg et al., 2022).

2020 UME Ongoing

Preliminary data indicate 1,337 deaths were recorded in the UME area from all causes between December 1, 2020, and December 31, 2022 (Stock Assessment Report, US Fish and Wildlife 2022).

St. Johns

Patterns of SAV were studied in the lower St. Johns River from 2001 to 2019 (Goldberg and Trent, 2020) and revealed a significant decline in SAV bed extent and taxon richness, particularly from 2015 to 2019. Nine major storm events between 2015 and 2018 physically damaged the vegetation, increasing water turbidity and reducing light availability, while persistent eutrophic conditions from phytoplankton blooms further degraded water clarity. Common species like wild celery, southern naiad, and horned pondweed experienced severe declines, with some, like Micranthemum sp., that disappeared entirely by 2019. Although some species showed resilience, overall SAV abundance remained below pre-2015 levels. This indicates ongoing challenges for recovery due to environmental stressors and management of SAV communities in the river.

Citrus County

The abundance of SAV significantly declined in Kings Bay, with a decrease of roughly 72% between 2006 and 2013 (SWFWMD 2015). Vegetation declined due to water quality issues, growth of Lyngbya, and stress from increased salinity.

Due to saltwater intrusion from Hurricane Idalia, there was a loss of freshwater SAV in Citrus and Hernando Counties. Six manatees were found dead in 2024 in the Mud River due to a shift in forage from SAV to macroalgae. These mortalities were also linked to a lethal clostridial infection triggered by the change to a macroalgal diet (https://myfwc.com/research/manatee/rescue-mortality-response/statistics/mortality/2024/mud-river/).

Tampa Bay

Between 1950 and 1990, seagrass cover declined from 40,400 acres to 25,000 acres as the result of declines in water clarity and water quality. Although seagrass coverage improved, between 2016 and 2022, seagrasses throughout Tampa Bay declined again by 28%, or 11,518 acres, to an estimated 30,137 acres (data provided by

SWFWMD). The majority of those losses occurred in Old Tampa Bay, which is now at a historic low for seagrass coverage (https://shiny.tbep.org/seagrass-analysis/).

Recommendations

Since the existing forage within proposed critical habitat may be insufficient to support the current manatee population, we recommend extending the critical habitat to 50 kilometers from warm water refuges. This expansion will cover manatee home ranges, includes areas where forage is still available such as Mosquito Lagoon, be consistent with other proposed critical habitat designations, and safeguard forage resources that may shift due to environmental stressors. This proactive approach will also provide a buffer for manatees as climate change continues to alter the locations and conditions of suitable foraging areas. The rationale for the 50-kilometer increase is described below.

Rationale

Prior studies indicate manatees often travel as far as 50 km to forage habitats during winter months (Barton 2006; Deutsch et al. 2006). Tagged manatees in Tampa Bay travelled from Matlacha Isles to FPL on the Orange River (Koelsch and Barton, 1999: Barton, 2006) and from TECO powerplant to foraging grounds approximately 45 km away (Deutsch and Barlas, 2006).

Some home ranges of manatees are within 50 km of a warm water refuge. Stith et al. (2006) found that most telemetered manatees overwintering at Port of the Islands (TTI) were year-round residents, staying within 40 km of the winter aggregation site where they were tagged. Weigle et al. (2001) reported that 64% of tagged manatees remained within Tampa Bay or the three-county area, which included adjacent waters in Hillsborough, Pinellas, and Manatee Counties. Twelve percent of tagged manatees in the Atlantic subpopulation remained within a 50-kilometer range of their winter and warm season ranges year-round (Deutsch et al., 2003).

Criterion 6 of the proposal, which outlines how critical habitat was delineated, indicates that boundaries were extended beyond 18.6 m to include areas with continuous forage. This criterion was used in the following critical habitat areas: FL-04 Tampa Bay, FL-05 (Figure 2), Venice to Estero Bay (Figure 3), FL-08 Biscayne Bay to Deerfield Beach.

Mosquito Lagoon is not currently within the critical habitat designation even though FWC seagrass maps currently indicate ample forage in this location (FWC, 2022). Criteria 3 and 4 request comments on the boundaries of specific critical habitat areas and on special management considerations, including potential impacts of climate change.  Mosquito Lagoon is currently occupied by manatees and has ample forage but is located within 50 km of the Cape Canaveral Energy Center (CCEC) (Figure 4). The critical habitat proposal states that Mosquito Lagoon was not included in critical habitat because this habitat is farther than 18.6 miles from the nearest primary or secondary warm water refuge. The entrance to Haulover Canal/Mosquito Lagoon is located about 4 kilometers beyond the 30-kilometer cutoff. If the Service is willing to extend critical habitat for Unit FL-04 and FL-05 beyond 30 kilometers to include continuous forage, Mosquito Lagoon should be included in critical habitat designation.

Aerial surveys from Kennedy Space Center indicate a shift in manatee habitat use from the Banana River (BR) to Mosquito Lagoon (ML), driven by the declining forage availability in the Banana River (NASA, 2023). Historically, manatees have been present in ML outside of extreme cold periods, though surveys by FWCC, MOTE, and FPL/IHA, along with anecdotal evidence from NASA’s sea turtle netting and aerial boat surveys, recorded much lower manatee abundance in ML compared to BR. This was assumed to be due to ML’s higher salinity and increased boating activity.

However, beginning in late 2015, large numbers of manatees were observed in ML as their presence in BR began to decline. In 2016, NASA expanded its manatee surveys to cover the southern part of ML up to the Brevard/Volusia County line, focusing on the summer months. That year saw a sharp drop in manatee numbers in BR and an increase in ML. By 2017, BR numbers returned to average levels, but in 2018 and 2019, BR numbers remained low while ML saw an exceptionally high presence of manatees. This pattern has continued through recent aerial surveys from 2022-2024 (Table 1).

These findings highlight the critically important role of Mosquito Lagoon as a forage habitat for manatees during the ongoing Unusual Mortality Event. Its resources were integral in reducing manatee mortalities that would have otherwise increased due to forage scarcity in areas surrounding the Cape Canaveral Energy Center and throughout the Indian River Lagoon. It is essential that Mosquito Lagoon be included in critical habitat designation to protect this vital resource for manatees.

Date	Mosquito Lagoon	Banana River
1/18/2022	1	0
2/11/2022	5	3
2/24/2022	329	104
3/9/2022	271	79
3/30/2022	312	67
6/7/2022	1082	63
7/6/2022	856	35
8/11/2022	858	45
9/20/2022	600	66
10/11/2022	689	23
10/25/2022	696	19
1/8/2023	102	4
1/24/2023	44	1
2/10/2023	447	53
3/9/2023	538	86
5/18/2023	629	223
6/8/2023	288	204
6/29/2023	480	226
7/19/2023	740	247
8/22/2023	597	342
9/19/2023	438	274
10/17/2023	302	209
11/22/2023	389	72
1/30/2024	93	119
2/23/2024	616	227
3/21/2024	363	419
5/16/2024	127	270
6/18/2024	85	223
7/10/2024	156	186
8/19/2024	419	444

Loss of warm water habitat refuges and networks

One of the most significant threats to manatees is the loss of warm water wintering habitat, also referred to as warm water refugia (Valade et al., 2020). Warm water refuges are categorized by refuge type – natural (spring or thermal basin) or artificial (power plant outfall/ industrial sites); by thermal quality – high, medium, low; and by refuge classification – primary or secondary manatee use (Valade et al., 2020). It is generally accepted that, in order to reduce future CO2 production, electric utility companies will phase out the remaining fossil fuel-dependent warm-water discharges within the next 30 years. The Florida Manatee Warm Water Habitat Action Plan (WWHAP) provides an overview and management goals aimed at addressing the loss of warm-water wintering habitat, both natural and artificial, and lists all warm-water sites with documented manatee use. The WWHAP is also a guiding document for the newly formed Atlantic Regional Partnership Teams – groups made up of a variety of partners with interests, resources, or technical expertise in the region and/or in manatee habitat conservation who provide suggestions or recommendations for potential warm-water habitat enhancements, offer creative solutions at a project scale, provide information on opportunities for additional partnerships and funding for implementation of said projects, and aid the FWC and USFWS in overall project development where appropriate.

The proposed critical habitat rule identifies all natural warm-water sites classified as primary refuges in the WWHAP (Valade et al. 2020, pp. 25–30) as essential to the conservation of the Florida manatee. Additionally, natural warm-water sites classified as secondary refuges with either reliable (high or medium) thermal quality or established manatee use in the WWHAP are also deemed essential (Valade et al. 2020, pp. 25–30). However, the proposed rule provides no explanation for excluding warm-water outflows from artificial power plants from the critical habitat designation. This omission is concerning, especially given that the U.S. Fish and Wildlife Service has included artificial habitats in critical habitat designations for other species. It is critically important to include artificial warm-water outfalls in the current critical habitat designation to ensure adequate protection for the Florida manatee as the species is weaned off of artificially warmed water and transitions toward increased reliance on warm water springs and passive thermal basins.

Recommendations

We recommend extending critical habitat boundaries to include all waters associated with primary artificial warm-water sites, as well as secondary artificial warm-water sites with high or medium thermal quality or established manatee use, as defined by the Manatee Warm Water Habitat Action Plan. The rationale for this recommendation is outlined below.

Rationale

Historically, Florida manatees depended on only natural sources of warm water to survive the winter. Today, it is estimated that over half of manatees in Florida depend upon artificial sources of warm water for shelter during the winter months (Laist & Reynolds, 2005). Following the advent of power plants which utilized once-through cooling, the winter range of the Florida manatee has expanded northward to areas that do not have, or have lost, natural sources of warm water (Valade et al., 2020). On Florida’s Atlantic Coast, most warm-water refuges are artificial, and the majority of the manatee population relies on just four sites with few natural warm-water options available (Spellman, 2016). Such is the case in the Northern Indian River Lagoon, where Martin et al. (2015) estimated that 70% of the wintering east coast manatee population were in Brevard County during a coast-wide survey. Further, 48.5 percent of all Florida manatees observed during winter counts were counted at power plant outfalls (Laist et al. 2013, p. 4).

The proposed critical habitat revision separates the physical or biological features essential to the conservation of the Florida manatee by the refuge type – natural warm-water sources vs. artificial. While the goal of manatee conservation managers is to wean manatees from artificial sources of warm-water, it is imperative to recognize and mitigate for the fact that nearly two-thirds of Florida manatees depend upon the cooling discharges from power plants to survive (Valade et al., 2020). Manatees exhibit strong site fidelity which may lead to large scale cold related mortality if such sources of warm water are eliminated before appropriate alternative warm water sources are secured (Valade et al., 2020).  Therefore, it is imperative that artificial warmwater sources receive critical habitat designation analogous with natural warmwater sources. Such designation ensures these habitats receive the protection needed to support manatees that rely on them. Other species managed by the U.S. Fish and Wildlife Service already benefit from having artificial habitats included in their critical habitat designations (Table 2). This precedent underscores the importance and feasibility of extending similar protections to artificially warmed water for manatees. This protection should be paired with the continued attempt to restore the quality of and access to natural warm water sources, but protection of existing warm water sources on which manatees currently depend must be guaranteed.

Species	Location	Corresponding Rule
American crocodile	Cooling canal system of FPL Turkey Point Nuclear Plant “The majority of the action area, including the [cooling canal system] and the southeastern portion of the Turkey Point site, is designated critical habitat for the crocodile. The Action Area contains approximately 22,790 ac of crocodile critical habitat (Figure 1). While FPL has made improvements to critical habitat by adding nesting habitat and digging freshwater ponds, critical habitat within the CCS has degraded with increased salinity and decreased prey abundance.”	20190725_Letter_Service to NRC_2014-I-0177-R001 (p.25)
Streaked horn lark	Dredge Islands in the Columbia River “On the Columbia River Island sites, only a small portion of each island is designated as critical habitat for the streaked horned lark; most of the areas mapped are used by the Corps for dredge material deposition in its channel maintenance program. Within any deposition site, only a portion is likely to be used by the streaked horned lark in any year, as the area of habitat shifts within the deposition site over time as new materials are deposited and as older deposition sites become too heavily vegetated for use by streaked horned larks (p.23).”	78 Fed Reg 61506, 61508 (Oct. 3, 2018)
California Tiger Salamander (Ambystoma californiense)	Artificially created cattle/agricultural stock ponds “(12) The PCEs of critical habitat for the Central population of the California tiger salamander (Ambystoma californiense) are the habitat components that provide: (i) Standing bodies of fresh water (including natural and manmade (e.g., stock)) ponds, vernal pools, and other ephemeral or permanent water bodies which typically support inundation during winter rains and hold water for a minimum of 12 weeks in a year of average rainfall.”	70 Fed. Reg. 49380, 49411 (Aug. 23, 2005)
Chiricahua leopard frog	Artificially created cattle/agricultural stock ponds “In ponds designated as critical habitat, most of which are impoundments for watering cattle or other livestock, designated critical habitat extends for 20 ft (6.1 m) beyond the high-water line or to the boundary of the riparian and upland vegetation edge, whichever is greatest. Chiricahua leopard frogs are commonly found foraging and basking within 20 feet of the shoreline of tanks.”	76 Fed. Reg. 14126, 14139 (March 15, 2011)
Rufa red knot	Artificial habitat includes human made islands and dredged spoil deposition sites “Unit TX–11 consists of 15,400 ac (6,236 ha) in Cameron County, Texas. The Boca Chica gulf shoreline portion of this unit begins south of the Brownsville Ship Channel and extends approximately 6.5 mi (10 km) to the south. Within the South Bay, the northern boundary is south of Brownsville Ship Channel dredge spoil placement areas, and the southern boundary is north of the Rio Grande River.” “(74) Unit SC–25: Turtle Island and Tomkins Island Beaches, South Carolina. (i) Unit SC–25 consists of approximately 1,771 ac (717 ha) on Turtle Island (a sea island), and Tompkins Island (a human-made island) in Calibogue Sound in Jasper County.”	86 Fed. Reg. 37410, 37435 (July 15, 2021).
Florida bonneted bat	Artificial structures as special management considerations, while excluding them from the designation: Natural roosting habitat appears to be limiting, and competition for tree cavities is high (see Competition for Tree Cavities under the Factor E discussion in the final listing rule (78 FR 61004, October 2, 2013, p. 61034)). To help conserve the Florida bonneted bat, efforts should be made to retain tall trees, cavity trees, trees with hollows or other decay, and snags wherever possible to protect habitat, reduce competition for suitable roosts, and bolster or expand populations within the species’ known range (Angell and Thompson 2015, p. 187; Braun de Torrez et al. 2016, pp. 235, 240; Ober et al. 2016, p. 7). The use of artificial structures for the Florida bonneted bat may also be beneficial in some locations, especially where roosting structures are lacking or deficient (see Use of Artificial Structures (Bat Houses)	89 Fed. Reg. 16624, 16645 (March 7, 2024).
Green sea turtle	Beach renourishment/dune restorations that mimic natural conditions “Threats to the PBFs identified within Unit HI–01 include habitat loss, modification, and degradation of nesting and basking beach habitat, naturally caused disasters (i.e., hurricanes and tsunamis), invasive nonnative vegetation, and presence of terrestrial and marine debris. Special management considerations or protection measures to reduce or alleviate the threats may include conducting habitat restoration or management and removing terrestrial debris from the beaches and marine debris that washes ashore. All lands within this unit are managed by the Hawai1i Division of Forestry and Wildlife (HDOFAW) for conservation purposes as part of the State’s wildlife sanctuary (HDOFAW 2022, entire) and the Papaha ¯naumokua ¯kea Marine National Monument, which provides additional management guidance and protection of the nesting and basking grounds for green turtles”	88 Fed. Reg. 46376, 46385 (July 19, 2023).

Additional Locations for Consideration that Contain the Physical and Biological Features of Critical Habitat Designation

The critical habitat designation asks for information regarding any additional areas occurring within the range of either subspecies that are within the jurisdiction of the United States (the Gulf and Atlantic Coasts of the United States for the Florida manatee) that should be included in the designation because they (i) were occupied at the time of listing and contain the physical or biological features that are essential to the conservation of the subspecies and that may require special management considerations or protection, or (ii) were unoccupied at the time of listing and are essential for the conservation of the subspecies. There are two specific locations that we recommend including in critical habitat designation: Harbor Branch Oceanographic Institute and the entirety of the Ocklawaha River.  Both of these locations provide essential travel routes to warm water or have established use by manatees during winter months.  The ongoing planned reduction in artificial warm-water sites emphasizes the urgent need for access to sustainable, natural warm-water habitats for manatees.

Recommendations

We recommend adding Harbor Branch and the entirety of the Ocklawaha River to the proposed critical habitat designation due to their warm water capabilities and essential travel corridor to warm water sites. Rationale for the two sites are below.

Rationale

Criterion 5 of the Service’s request for comments asks for information on areas not occupied at the time of listing that would qualify as habitat for the species and are essential for the conservation of the species. Since 1976, the St. Johns River has been designated as critical habitat for manatees. Unfortunately, the Riverway’s natural flow is obstructed by the Rodman (or Kirkpatrick) Dam and Buckman Lock, limiting manatees’ access to critical warm springs along the Ocklawaha River. If the Riverway’s natural flow were restored, the Ocklawaha and Silver Rivers, along with Silver Springs State Park, could provide manatees with vital warm water refuges during winter. The Ocklawaha River connects to 20 freshwater springs, submerged under high water levels caused by the dam. These springs could serve as essential warm water habitats providing year-round water temperatures of around 72°F.

The Clearwater Marine Aquarium Research Institute (Ross et al., 2023) reports that manatees use the entire Ocklawaha River System during winter months. Data from tagged individuals show that 185 uniquely identifiable manatees travel through this system, although this number only includes those that can be identified and does not account for all manatees in the area. Physical and environmental data collected from multiple springs within the upper Ocklawaha River (Ross et al., 2023) identified Apopka, Bugg, and Palatlakaha Springs in Lake County’s Chain of Lakes as suitable and sustainable winter habitats for manatees. However, accessing these springs requires manatees to navigate through two to three lock systems. Despite this, citizen scientists in the Chain-of-Lakes systems reported 57 manatee sightings during the winter months, highlighting that manatees are actively using these areas as warm-water habitats. The critical habitat proposal specifies that travel corridors are essential for meeting the basic needs of both subspecies of the West Indian manatee. In particular, the proposed critical habitat for Unit FL-09 (Boynton Beach to Fort Pierce) and Unit FL-10 (Vero Beach to the Northern Indian River Lagoon) highlights the importance of travel routes, including canals and basins that lead manatees to essential warm-water refuges. Similarly, the Ocklawaha River serves as an indispensable travel corridor for manatees toward vital warm-water habitats within the Ocklawaha River System.

Further, the Ocklawaha River is a critical calving area for Florida manatees, making it essential to include in the final critical habitat designation. Calving areas are fundamental to the survival and reproduction of the Florida manatee, as they provide sheltered backwaters with minimal disturbance that are frequently used by cow/calf pairs (SSA at 33). Protecting such habitats aligns with the Service’s mandate under the Endangered Species Act (ESA), which prioritizes conservation efforts to ensure the continued survival and population growth of protected species. Ensuring the survival and reproduction of manatees requires safeguarding habitats where females give birth and nurture their young.

Kernel density analysis of perinatal carcasses can help identify areas where female manatees give birth. This method estimates the intensity of occurrences, such as perinatal mortality, across a geographic area and produces a heatmap that highlights areas with higher or lower concentrations of carcasses (Weglarczyk, 2018). A kernel density analysis performed on Florida Fish and Wildlife Conservation Commission’s (FWC) Manatee Carcass Recovery Locations in Florida dataset by Save the Manatee Club provides a clear indication of these hotspots. This dataset, spanning recoveries from 1974 through May 2021, was filtered for perinatal carcasses and analyzed using ArcGIS Pro 3.1.2 and the Kernel Density tool. The resulting analysis identified areas of high perinatal mortality for the Duval County area, depicted in Figure 5 with darker shades of blue indicating greater concentrations of carcasses. Overlapping these data with the proposed critical habitat boundaries, shown in orange, reveals that while many perinatal mortality hotspots fall within these boundaries, others do not.

Given their significance as calving grounds, these regions must be included in the critical habitat designation to ensure comprehensive protection for manatees and their offspring.

Therefore, we recommend including the entire Ocklawaha River in the critical habitat designation, as it serves not only as a vital calving area but also as an essential travel corridor to the warm-water habitats within the Ocklawaha River System.

In addition, Harbor Branch is absent from the critical habitat designation, despite five studies and aerial surveys showing consistent winter use by manatees from 2008 to 2023 (Nys, 2010; Robinson, 2013; Goldsworthy, 2016; Gomez, 2018; Brady, 2020; Mote aerial surveys 2014-2024). The Manatee Project at Harbor Branch Oceanographic Institute was established in 2009 (Nys, 2010). Land-based observations and photo-identification techniques have been used to document over 529 individuals and match 115 animals in the MIPS database (Gomez, 2018). Aerial surveys conducted by Mote Marine Laboratory (Table 3) show use of Harbor Branch from 2013-2024. Further, analysis of ambient air temperatures revealed that as temperatures dropped, more manatees were observed at Harbor Branch (Brady, 2020, p. 56).  This fifteen-year data set supports Harbor Branch’s established use and should be added as critical habitat. If Harbor Branch is included in critical habitat designation, the 18.6-mile critical habitat boundary would extend to include Moore’s Creek, which is adjacent to the Manatee Observation and Education Center in Fort Pierce. Moore’s Creek has functioned as a passive thermal basin consistently utilized by manatees from 1997 to 2020 (Tennant et al., 2024).

Date	Number of animals observed
11/20/2014	32
12/14/2014	20
1/29/2015	2
2/14/2015	13
1/13/2016	0
1/25/2016	5
2/28/2016	19
1/31/2017	12
12/14/2017	15
1/15/2018	15
1/10/2019	65
1/22/2019	0
1/6/2020	20
1/24/2020	7
3/2/2020	13
1/9/2021	3
1/19/2022	5
1/31/2022	7
12/28/2022	5
1/17/2023	1
11/30/2023	3

DoD Lands

According to the document, the Service is excluding certain lands from critical habitat designation because the U.S. Department of Defense has an approved Integrated Natural Resources Management Plan (INRMP) for these areas.

Recommendations

We recommend updating the INRMP for MacDill Air Force Base to include proposed critical habitat and completing the formal review of the Jacksonville Naval Air Station to ensure that the proposed critical habitat is adequately protected. Further, to ensure transparency, the Service should clearly outline in the critical habitat proposal how they will collaborate with the respective bases to protect critical habitat. This should include information on whether these areas have been recently evaluated and what actions will be taken if areas included in the proposal are not currently designated as critical habitat on the respective bases.

Rationale

According to the DoD documents. revisions, updates, and final approval of the INRMP must be coordinated with the U.S. Fish & Wildlife Service, the Florida Fish & Wildlife Conservation Commission, and other respective agencies. The INRMP must be reviewed annually and undergo a formal review every five years, with any revised plan requiring approval from a collaborating agency, including the Service.

The five-year reviews of the Integrated Natural Resources Management Plans (INRMPs) for both Jacksonville Naval Air Station and MacDill Air Force Base were completed in 2019, and both locations now require a current formal review. In addition, the IRNMP for the 278 acres of DoD lands owned by Space Force was not provided in the references, and it is unclear if there is an IRNMP in place for this location.

According to page 47 of the document, the Service is exempting 4,415 acres of MacDill Air Force Base lands within the FL-4 unit (Tampa Bay) due to the presence of an approved Integrated Natural Resources Management Plan (INRMP) for this area.  As stated in the MacDill AFB 2022 INRMP, no part of MacDill AFB or the surrounding marine area has been designated as critical habitat for the Florida manatee. The nearest designated critical habitat is located approximately 7 miles south of MacDill AFB at the mouth of the Little Manatee River in southern Hillsborough County.

We recommend updating the INRMP for MacDill Air Force Base to include proposed critical habitat and completing the formal review of the Jacksonville Naval Air Station to ensure that the proposed critical habitat is adequately protected.

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References

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