Dugong Conservation

Chetumal Bay supports a considerable population of the endangered Antillean manatee (Trichechus manatus manatus) and was declared a Natural Protected Area (NPA) in both Mexico as the Sanctuary of the Manatee, and in Belize as Corozal Bay Wildlife Sanctuary. In order to understand the role of NPAs in manatee conservation, information from satellitetracked manatees was analyzed. Home Range and Centers of Activity (COA) were calculated. Several individuals travelled up major freshwater sources. Only two of these areas has a protected status. The location, number and size of COAs varied strongly among individuals and sometimes fell outside NPAs. NPAs in the Caribbean are outstanding refuges for manatees, but some of the individuals may not remain in highly protected areas, and travel long distances venturing into river systems and other unprotected areas.

In addition to hunting, other factors threaten the populations of the Amazonian manatee through occasional degradation and even loss of habitat for the species, leading to a decreased availability of habitat for performing key events in its cycle life (feeding, reproduction, etc.). Deforestation of riparian environments, water pollution (a serious threat to an herbivorous aquatic species, by damaging its habitat and a decrease of dietary plants), construction of hydroelectric plants, and accidental capture by fishing nets are also potential risks to this species (Rosas, 1991; Trujillo et al., 2006. Urinalysis can be useful in determining the health status of captive animals. In this context, chemical, physical and sedimentological urinalysis could be a useful tool to monitor the health status of wild Amazonian manatees , increase our knowledge of its physiology, and provide a scientific foundation for future physiological studies of this species. Due to the difficulty of obtaining biological samples, few data are available on the characterization, collection and production of urine in aquatic mammals in general, and very little is known about the composition of Amazonian manatee urine. The only available information on the urine of this species derives from analyses conducted in the Laboratory of Aquatic Mammals (LMA) of the Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazon, Brazil. Some of these results were recently published (Pantoja et al., 2010), using urinalysis in order to establish normal ranges of urinary parameters to help monitor the health of this species in captivity. To accomplish this, the authors performed chemical urinalysis to obtain quantitative values of glucose, urea, creatinine, uric acid and amylase levels obtained using colorimetric spectrophotometry. Other important information derived from analyses conducted over thirty years ago with seven captive specimens kept in the Laboratory of Aquatic Mammals (LMA) of the same institute. This information came from urine collection carried out by Robin Best with captive Amazonian manatees in 1978. These data were not published, but could be accessed from LMA's files, and were used as a comparison for the data obtained in this investigation, which presents the results from chemical, physical and sedimentological analysis of Amazonian manatees' urine in order to continue research useful for monitoring health in captivity. We believe that any decisions about an animal's release or return to the wild should be made with caution and security. The safety of the individual animal as well as the continued well-being of the wild host population should be carefully considered. The information provided by this study can help support scientifically based reintroduction programs to reestablish or reinforce endangered native wild populations of Amazonian manatee. Urinalysis can be a useful tool since it can help assess the health status of animals proposed to be released or returned to the wild. By establishing baseline data on physiological parameters using healthy captive animals, this study may also contribute to Amazonian manatee conservation since urine collection from wild manatees can help evaluate the condition of wild populations. Likewise, urinalysis could be used to monitor the health of other captive animals, such as those that may be reintroduced to former areas of habitat from which the species was removed by excessive hunting. Finally, this study extends our knowledge of the manatee's basic physiology, hopefully contributing to its effective management and conservation.

. The Aquatic Mammals and Reptiles of the Amazon. In: Sioli, H (ed.). The Amazon, Limnology and Landscape Ecology of a Mighty Tropical River and its Basin. Dr. W. Junk Publisher, the Netherlands, pp. 371-412. Crema, L.C. 2017. Caracterização de igapós de águas claras e pretas e suas disponibilidades alimentares para o peixe-boi-da-Amazônia (Trichechus inunguis). PhD Thesis. Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil. 117 f.: il.

Seagrass provides a crucial habitat for numerous marine species and serves as a vital food source for endangered species, like dugongs. While extensive research on restoration has been conducted on certain temperate and slow-growing climax seagrass species, limited attention has been given to tropical pioneer species. This study aimed to assess and compare two restoration methods for the pioneer seagrass Halodule uninervis and evaluate their potential for biodiversity recovery after planting. We conducted a field experiment at subtropical Inhaca Island, southern Mozambique, testing the efficiency of two planting methods (plugs and single shoots) and two planting densities ($100 and $300 shoots/m 2). We monitored seagrass shoot density in two sites for 16 months, and benthic macrofauna density for 12 months. Results demonstrated that seagrass could grow in all combinations of planting methods and densities in both sites. Specifically, the single shoot method at the high-density treatment proved the most effective, resulting in approximately 1000 shoots/m 2 within a year. Faunal densities, primarily dominated by polychaetes followed by malacostraca, bivalves, and gastropods, indicated rapid colonization of the planted areas, especially in the high-density treatments. Our findings suggest that restoring H. uninervis is feasible using the two tested planting methods. This is particularly significant because H. uninervis is a preferred dugong food source, and its decline due to anthropogenic activities could be reversed through restoration efforts. Nonetheless, conserving existing seagrass should be the primary focus, and restoration approaches should be employed as a valuable tool for managing coastal areas.

After many months of postponing consideration of a petition to downlist Florida manatees from "Endangered" to "Threatened" status under Florida law, the Florida Fish and Wildlife Conservation Commission (FWCC) has just taken a step toward such action (see story in this issue). Although the Commission's vote at its April meeting did not directly affect manatees, it preserved the objectionable regulatory language according to which "Threatened" in Florida is equivalent to what the rest of the planet calls "Endangered". The implication is clear, and the stage is now set: application of this lingo to manatees will sooner or later result in downgrading the degree of state protection for which they are deemed eligible. Since we already editorialized at length on this topic in Sirenews Nos. 38 (October 2002) and 42 (October 2004), little needs to be added at this time. Even though federal protection for manatees remains in place (for now; but see news items below), and any move by the state to actually downlist manatees is still several months and several

Present study consists the survey conducted in coastal villages from Dhanushkodi to Kannyakumari in the Gulf of Mannar (GoM) and from Dhanushkodi to Kodikkarai in the Palk Bay for understanding status of dugong. Survey provided sightings, distribution and population status of dugong in the GoM and the Palk Bay. Dugong was found to be distributed from Dhanushkodi (Ramnathpuram District) to Idinthakarai village (Tirunelveli District) in the GoM and from Dhanushkodi (Ramnathpuram District) to Adirampattinam (Thenjavur districts) in the Palk bay. Likely maximum population of dugong was estimated 78 and 80 individuals in GoM and Palk Bay respectively.

The Antillean manatee is a poorly studied marine mammal in Costa Rica. Its distribution covers the entire Caribbean coast, but sighting reports are scarce. This research was conducted in three protected areas (PA) where the species is primarily observed. The objectives were to determine the density patterns of sightings and grazing spots; to explore the relationship between grazing spots and sightings with geographic and temporal variables, for PA separately; to study the frequency of sightings and grazing spots according to season, month, and period of the day, for PA together; and to determine the pertinence of using a marine ecology application MarEco to register manatee sightings by the public. Data on manatee sightings and grazing spots gathered with the MarEco app, under a citizen science mechanism, were complemented with data obtained by the Tortuguero Conservation Area Administration (TCAA) through other means. The number of sighting records registered through MarEco during nine months was alike to the number of records reported to the TCAA over six years in two of the PA studied. The areas with the highest density of grazing spots and sightings matched with studies conducted 10 to 20 years ago. In two of the PA, sightings were most often associated with the rainy season, while fresh grazing spots were specially counted from 6:00 h to 8:59 h. The results suggest that manatees exhibit high site fidelity in the three PA, that their increased presence during the rainy season is likely due to increased availability of food, and that they perform feeding activity predominantly at night.

After many months of postponing consideration of a petition to downlist Florida manatees from "Endangered" to "Threatened" status under Florida law, the Florida Fish and Wildlife Conservation Commission (FWCC) has just taken a step toward such action (see story in this issue). Although the Commission's vote at its April meeting did not directly affect manatees, it preserved the objectionable regulatory language according to which "Threatened" in Florida is equivalent to what the rest of the planet calls "Endangered". The implication is clear, and the stage is now set: application of this lingo to manatees will sooner or later result in downgrading the degree of state protection for which they are deemed eligible. Since we already editorialized at length on this topic in Sirenews Nos. 38 (October 2002) and 42 (October 2004), little needs to be added at this time. Even though federal protection for manatees remains in place (for now; but see news items below), and any move by the state to actually downlist manatees is still several months and several

h i g h l i g h t s • Direct/indirect sample methods combined gave best occupancy/detection estimates. • Detection probability was high and positively related with macrophyte coverage. • Final occupancy estimate can be baseline to Purus River long-term monitoring studies. • Hierarchical model potential to know aquatic mammals distribution. • Our data support the selection of priority areas for the species' conservation.

Traditional knowledge gained through daily interactions with the environment can yield insights into processes at temporal or spatial scales that may be overlooked by conventional scientific research. Ninety interviews were conducted with riverine people in the vicinity of Anavilhanas National Park, Tapajós–Arapiuns Extractive Reserve and Tapajós National Forest in the Brazilian Amazon, with the aim to increase knowledge of the feeding habits of the Amazonian manatee Trichechus inunguis and evaluate its conservation status in contrasting protected areas. In Anavilhanas respondents identified 31 plant species consumed by the manatee, of which vines had the highest cognitive salience index value (the summed importance of each plant species), even though they are available to manatees only during the high-water season. In the Tapajós region 37 plant species were identified, with submerged species with floating leaves being the main component of the manatee's diet. Although hunting ...

Amazonian manatees live in black water rivers and lakes in the Amazon basin. A study of Amazonian manatees in the Cuyabeno Reserve conducted by Timm et al. [1] in 1983 gave first information on distribution of manatees in the Cuyabeno Reserve and they suggested a possible extinction of the Amazonian Manatee in the following decade. Here I present results of observations, and interviews, realized 13 years after the first study as complementary observations during a research project on Amazon River dolphins (Inia geoffrensis) from 1996 to 1999. We surveyed during more than 127 days covering about 6.175km in manatee habitat with more than 456 hours continuously observing black water rivers and lagoons and we carried out manatee surveys paddling in the Lagunas Grandes de Cuyabeno. Interviews with tour guides, park rangers and native Indians give a complete sighting list for the presence of manatees and insight into the current situation in the Reserve. The relative abundance of manatees in the Cuyabeno River is 0.01 animals/h effort and even less in the Lagartococha River with 0.007 animals/h effort. Populations in the Lagartococha River seem to be severely reduced. Hunting in both rivers continued despite legal protection with 16 manatees killed from 1995 to 1998. Overall 40 to 49 animals were seen in the Cuyabeno Reserve from 1996 to 1998. Even though, predictions that manatees would be extinct by 1993 were not fulfilled, they are rare in the Reserve and living in a protected area does not necessarily safeguard this species.

In India, dugong populations and their habitats are under pressure from several factors, including seagrass degradation caused by high turbidity and pollution, ghost nets, bycatch, poaching, fragmentation of seagrass habitats, and climate change. We reviewed the strandings of vulnerable Dugongs (Dugong dugon, Müller, 1776) in the Gulf of Kutch, Gujarat with prevailing threats factors. Dugong strandings data was collected through the Friends of Dugong Network, established in the Gulf of Kutch, to promote citizen science to recover obscure dugongs and records from the published literature. We could document 24 incidents of strandings with 29 dugongs between 1877 and 2022. In the Gulf of Kutch, dugong mortality incidents were reported with discontinuous occurrences, and the causes for their strandings were also unknown. However, fisheries bycatch and ghost nets in the seagrass meadows seem to be major causes for recent strandings of dugongs.

A Dugong conservation reserve was proposed jointly by WII and the Tamil Nadu State Forest Department in North Palk Bay, Tami Nadu, in 2020. Subsequently, the Hon’ble State Forest Minister in the Tamil Nadu state assembly announced the need to establish the Dugong conservation reserve to conserve dugongs. The Tamil Nadu government declared about 448 square kilometers of area in the northern part of Palk Bay as a 'Dugong conservation reserve' notified by Gazette Order G.O. Ms. No. 165, Environment, Climate Change, and Forests (FR.5) dated September 21, 2022.

Dugongs, threatened globally, are regionally endangered in India (Marsh & Sobtzick, 2015). Due to their low population size, fragmented foraging habitats, and high negative interaction with fisheries, the government of India has placed them under Schedule I of the Wildlife Protection Act, 1972, according to their highest protection status. Further, as a signatory to the ‘CMS-UNEP Dugong Memorandum of Understanding’, it constituted a ‘Task Force for Conservation of Dugongs for proactive management of
dugong habitats and the implementation of the Endangered Species Recovery Program for dugongs. In 2015, the Government of India assigned the task to the Wildlife Institute of India to conduct scientific
monitoring of dugong populations and seagrass habitats, create awareness of dugong conservation, and build the capacity of frontline agencies to enable dugong population recovery. This program is currently under implementation at all three dugong distribution sites in the state of Gujarat (Gulf of Kutch), Tamil Nadu (Palk Bay & Gulf of Mannar), and Andaman & Nicobar Islands (Sivakumar et al. 2019). Under the aegis of the Dugong Recovery Program, May 28, 2020, was recently celebrated as ‘Dugong Day’ in India. This was the first time a day was dedicated to dugong conservation awareness anywhere in the world. The significance of the day comes from the signing of the CMS-UNEP Dugong MoU by India on May 28, 2008, for the conservation and management of dugongs and their habitats.

Dugongs is a protected herbivorous marine mammals (Suwelo et al., 1992) and included in vulnerable category of IUCN(International Union for the Conservation of Nature and Natural Resources) and Appendix I CITES (Convention on International Trade in Endangered Species) (IUCN 2012). Dugong population continues to decline due to the human threat (Suwelo et al., 1992). Another factor is because Dugong has a low reproductive rate (Hindell & Kirkword 2003). Ex-situ conservation of dugong is become important and has conducted by Sea World Indonesia, Taman Impian Jaya Ancol, Jakarta. Research on dugong feeding behaviour can help the ex-situ conservation of dugong. This because feeding behaviour is a main daily behaviour of dugong in the sea (Chilvers et al., 2003). The aim of this research was to describe feeding behaviour of two dugong in Sea World Indonesia. Observations were made in SWI Dugong aquarium with a diameter of 10 meters and two different depth (2 meters and 5 meters). Observations were made during two weeks on December 2012. Behavioral observation time was divided into morning (9:15 to 09:35), (11:30 to 11:50) and (14:30 to 14:50) observations. The feeding behavior observed was hand-fed, surface-fed and bottom-fed. Daily observations of dugong feeding behavior were done using focal animal sampling and ad libitum sampling. The data obtained was displayed in the form of tables and graphs. The data was analyzed using descriptive analysis reinforced with statistical tests. The statistical tests used were the t-test and ANOVA test. Hand-fed behavior of male dugong (31,30%) was higher than female (29,67%). Results from t-test showed that the hand-fed behaviors of both dugongs were not significantly different. Meanwhile, the other t-test result for surface-fed behavior and bottom-fed behavior of both dugongs was significantly different. Surface-fed behavior of male dugong (65.83%) was higher than female (32.08%). Bottom-fed behavior of male dugong (6.23%) was lower than females (36.63%). Hand-fed behaviour and feed on surface are the adaptation of feeding behavior in captivity. Feed on bottom behaviour is the behavior that similar to dugong feeding in the wild, which is grazing. Based on the observation, it is known that both dugong, male dugong especially, have a good adaptation on hand-fed seagrass behaviour and feed on surface, while the female dugong maintain its natural feeding behavior.

Pubudugama and Sevvanthive villages for their cooperation and sharing their observations, and also IUCN Sri Lanka country office for facilitating the conduct of this study. Finally, we wish to thank Mr. Niranjan Karunarathna (YZA) for numerous help during the preparation of this paper.

Ecosystem services are the benefits we derive from the ecosystems we occupy. These services are related to biodiversity and this interaction ensures the functioning of the processes necessary for their own maintenance. The aim of this study was to identify the perception of ecosystem services associated with West Indian manatee (Trichechus manatus) in their sites of occurrence in Brazil. Data collection was carried out using forms completed autonomously by professionals who participated in the elaboration of the National Action Plan for the Conservation of Sirenia in Brazil. Most respondents belong to private institutions and have more than ten years’ experience in these field. We found a positive and significant correlation between pressures and threats in manatees, that currently affect in ecosystem services and are expected to continue in the future. No differences were observed in perception regarding the presence of categories of ecosystem services. Thus, it is considered that ...

Background: Antillean manatee (Trichechus manatus) and Amazonian manatee (Trichechus inunguis) are the two species of manatees that occur in Brazil, and both are endangered. Studies on manatee disease in Brazil were previously based mainly on Florida manatees. In recent years, these studies have increased in Brazil. Thus, the objective was to carry out a survey of the publications of infectious and non-infectious diseases in the two species of manatees that occur in the country, to assist in the identification of threats to the species and in the health assessment of manatees in the country. Review: Regarding infectious and contagious diseases, parasites have affected both species of manatees in Brazil, such as Pulmonicola cochleotrema in wild T. manatus, Toxoplasma gondii in both species, and Cryptosporidium spp. also in both species, this being an important agent of zoonotic character. Giardia sp., another zoonotic parasite, has also been reported in both species of manatees in Brazil. Mycotic lesions caused by B. hawaiiensis have been described in calves of T. manatus in captivity. Meanwhile, Candida sp., Trichosporon sp., Rhodotorula sp., and Cryptococcus sp. have been identified in T. inunguis. Studies on viruses in manatees are still not widespread compared to other species; however, it has been verified that rotavirus is present in T. manatus in captivity. In studies carried out to identify bacteria in T. manatus, the following bacteria were isolated:

Background: Manatees are the most endangered aquatic mammals in Brazil. The current conservation scenario, together with their biological characteristics, raises concern with the future of this species. Pyothorax, also known as septic pleural effusion or pleural empyema, is characterized by the accumulation of a septic purulent exudate within the pleural space. Although this infection often has a multifactorial etiology, it is most commonly associated with respiratory tract disorders and trauma. Here, we report a case of pyothorax in a Antillean manatee (Trichechus manatus) held in captivity for acclimatization in Brazil.Case: A young, male Antillean manatee, aged 4 years and 11 months, measuring 227 cm in total length, and weighing 258 kg was held in captivity for acclimatization (natural environment) in Porto de Pedras in the State of Alagoas, Brazil. The animal died in February 2013 and was sent for necropsy at the CMA/ICMBio laboratory. The study was developed with authorisation...

conducted on wild manatees, 21,5% under human care conditions, and the rest a combination of both; the most common topics of study were 'ecology', 'conservation', 'morphology, anatomy and physiology', and 'behavior'. The literature on Antillean manatee has expanded significantly over the last two decades across the region, with most of the research published in just the last five (25.4%) to 10 (44.6%) years. Most of the published work has been by Brazilian, Mexican, and Colombian researchers. However, an important amount of research remains as theses in Portuguese or Spanish limiting the dissemination of results. Relevant limitations for research and publication in Latin American countries may have an impact on the published literature on Antillean manatees, including scarce funding, poor facilities, language-related difficulties, and lack of a culture of publication. Avenues to melt scientific barriers may include increasing governmental investment on research, strengthening international networks, and improving the support to publish in high-impact journals.

The Antillean manatee (Trichechus manatus manatus) is an endangered subspecies of the West Indian manatee inhabiting countries of South America, Meso America and the Caribbean. Basic and applied research is necessary to inform management plans for the effective recovery of this subspecies. The purpose of this study was to systematically review literature regarding Antillean manatees, without restriction of the research topic. Article selection and screening process are described. Our final database consisted of 456 publications, of which peer-reviewed literature (articles, reviews, and notes in research journals) represent the most important type (63.4%), followed by BSc, MSc, and PhD theses (28.1%). Most of the research (70%) was conducted on wild manatees, 21,5% under human care conditions, and the rest a combination of both; the most common topics of study were ‘ecology’, ‘conservation’, ‘morphology, anatomy and physiology’, and ‘behavior’. The literature on Antillean manatee has...

Many marine mammals exhibit diel trends in vocal production, which can provide information on habitat use and behavioral activity. In Belize, Antillean manatees (Trichechus manatus manatus) commonly inhabit small depressions in the substrate or deep-water coves known as "resting holes". Determining if manatees exhibit diel temporal trends in their call production rate and call types between microhabitats can provide insights into their diurnal and nocturnal activity patterns. Here, we investigate the diel vocalization patterns of wild Antillean manatees in two adjacent resting holes off of St. George's Caye, Belize. Recordings of manatees were made using a bottom-mounted hydrophone located near a reef barrier reef for nine days in July of 2017 and ten days in January of 2018. To explore if and how manatee acoustic activity differs between sites, we compared the number of calls per hour, the number of manatee positive hours, the number of tonal and atonal sounds, and the number of boats detected across sites. A total of 370 hours of acoustic recordings were analyzed resulting in the detection of 3,262 calls. There were no significant differences in the number of manatee calls produced per hour between sites. The average number of calls produced by manatees decreased over the course of several days. The proportion of tonal calls decreased with hours after sunset and increased in boat presence. These results suggest manatees in this region may exhibit different diel activity patterns which appear to be influenced by the characteristics of the environment. These findings can support ongoing conservation and management efforts to safeguard species in Belize.

Assessing the body condition of wild animals is necessary to monitor the health of the population and is critical to defining a framework for conservation actions. Body condition indices (BCIs) are a non-invasive and relatively simple means to assess the health of individual animals, useful for addressing a wide variety of ecological, behavioral, and management questions. The Antillean manatee (Trichechus manatus manatus) is an endangered subspecies of the West Indian manatee, facing a wide variety of threats from mostly human-related origins. Our objective was to define specific BCIs for the subspecies that, coupled with additional health, genetic and demographic information, can be valuable to guide management decisions. Biometric measurements of 380 wild Antillean manatees captured in seven different locations within their range of distribution were obtained. From this information, we developed three BCIs (BCI1 = UG/SL, BCI2 = W/SL3, BCI3 = W/(SL*UG2)). Linear models and two-way ...

Interviews with hunters and collection 4[ skul& indicate that Trichechus inunguis occurs throughout the region of the Amazon River estuaries f?om Amapd to the mainland of" Pard, including llha de Maraj6 and islands on its Atlantic coast. T. manatus has a disjunct distribution in Brazil, apparently occurring both on the coast of Amapd north of Cabo Norte and in the Rio Mearim (Maranhdo) as well as further to the southeast; it seems to have been exterminatedj)'om the Atlantic coast of Para and is absent from the Maraj6 region. Continued subsistence hunting can best he controlled by destruction of illegal camboas (fi, nee-like traps) which catch manatees at high tide. A reas deserving study are the coasts and inland lakes of eastern A mapd, the onO'place in the worm where two sirenian species might still be.[bund in sympato' or immediate proximity, amt the lower Rio Mearim in Maranh~o, whieh may still contain a sizable population ofT. manatus. Ecological studies in these areas shouM have particular relevance to hypotheses ~[ sirenian evolutiona O' interaetions, and manatee reserves shouM he established in both areas. DARYL P, DOMNING value to studies of sirenian evolutionary biology, but only one area in the world today provides any hope of finding two sirenian species living in sympatry. This area is the mouth, or mouths, of the Amazon river system in Brazil. The Amazonian manatee, Trichechus inunguis (Natterer 1883), is distributed in fresh waters throughout the Amazon basin, including the lower reaches of the Amazon (Rio Amazonas) itself (Bertram & Ricardo Bertram, 1973). The range of the West Indian manatee Trichechus manatus Linnaeus 1758, apart from North and Central America and the Caribbean Islands, includes fresh and salt waters of Colombia, Venezuela, the Guianas, and the coasts of the Brazilian Northeast (that is, on both sides of the Amazon estuaries) (von Pelzeln, 1883; Bertram & Ricardo Bertram, 1973; Banks da Rocha, 1971a,b) as well as the lower Orinoco River (Mondolfi, 1974). Despite repeated statements in the literature, which originate from a report by von Humboldt & Wiegmann (1838), there is no good evidence that T. inunguis ever occurred in the Orinoco basin, nor does it appear likely (in view of the locations of rapids in both rivers) that manatees of either species exist in the vicinity of the Casiquiare Canal or other natural connections between the Amazon and Orinoco drainage systems. Thus the Amazon mouth is the only area where the two species might be sympatric. Goeldi & Hagmann (! 904) reported T. inunguis from llha de Maraj6. Goeidi (in Dilg, 1909: plate 13) presented a map of manatee distribution in South America, showing T. inunguis in the Amazon basin and T. manatus on the coast of Amap~i north of Cabo Norte. He believed that the manatees on the coast south of the Amazon were T. inunguis, but cited no specimens or other data to support this (erroneous) conclusion, which was nonetheless repeated by subsequent writers. Pereira (1944), though asserting the existence of manatees throughout the area of the present study, including the Rio Mearim, not only cited no evidence for his conclusions but considered all New World manatees referable to T. manatus! Finally, Cabrera (1961) suggested that the coastal manatees of the Brazilian Northeast might be T. manatus, in contrast to the fluviatile inunguis. This identification has been confirmed for the present-day situation by Banks da Rocha (1971a,b) and for the 16th and 17th centuries by Whitehead (1977, 1978). De Carvalho & Toccheton (1969) and Pine (1973) reported a specimen of T. inunguis (M PEG 1518; see below) from near Bel6m. Apart from these, however, no published locality records of either species seem to be available from the Atlantic coasts of Parh or Amapfi, the lower parts of the Rios Amazonas or Tocantins, or Ilha de Maraj6, leaving in doubt whether their ranges overlap in this area. (Hybridisation is unlikely as T. inunguis has 56 chromosomes whereas T. manatus has 48; Loughman et al., 1970; White et al., 1976.) The results reported below were gathered in a survey of sites on the coasts of Amap~ and Pardi, the lower Rio Mearim in Maranh~o, and the eastern part of llha de Maraj6; that is, the areas where the identity of any existing manatee populations seemed to be most in doubt. The main objective was to determine the present

Fishing provides an important food source for humans, but it also poses a threat to many marine ecosystems and species. Declines in wildlife populations due to fishing activities can remain undetected without effective monitoring methods that guide appropriate management actions. In this study, we combined the use of unmanned aerial vehicle-based imaging (drones) with machine-learning to develop a monitoring method for identifying hotspots of dugong foraging based on their feeding trails and associated seagrass beds.

We surveyed dugong hotspots to evaluate the influence of gillnet fishing activities on dugong feeding grounds at Inhaca Island, Southern Mozambique. The results showed that drones and machine learning can accurately identify and monitor dugong feeding trails and seagrass beds, with an F1 accuracy of 80% and 93.3%, respectively. Feeding trails were observed in all surveyed months with the highest density occurring in August (6,040 ± 4,678 trails/km2)

There was a clear overlap of dugong foraging areas and gillnet fishing grounds, with a statistically significant positive correlation between fishing areas and the frequency of dugong feeding trails. Dugongs were found to feed mostly in Saco East, where the number of gillnet stakes was 3.7 times lower and the area covered by gillnets was 2.6 times lower than in Saco West.

This study highlights the clear potential of drones and machine-learning to study and monitor animal behavior in the wild, particularly in hotspots and remote areas. We encourage the establishment of effective management strategies to monitor and control the use of gillnets, thereby avoiding the accidental bycatch of dugongs.