SURVEY OF THE MANATEE´S (Trichechus manatus, Linnaeus, 1758) DISTRIBUTION, OCCURRENCE AND STATUS OF CONSERVATION IN THE NORTHEAST COAST OF BRAZIL
ABSTRACT
In the early 80's the first survey was conducted on the distribution of marine manatees in Brazil, which pointed out the north and northeast coasts as areas of occurrence, and recorded its disappearance in the Espirito Santo and Bahia States. Considering the absence of recent data, this study aimed to update existing information on the distribution and areas of occurrence of the Trichechus manatus in the Northeastern coast of Brazil, as well as evaluating the conservation status of species and to support the work of preserving this sirenian. The survey was conducted during the years 1990 and 1991 from the coast of Sergipe to Piauí. A questionnaire with eight questions was used being applied to fishermen. When we confirm the importance of location for the occurrence of the manatee, nautical raids were carried out in order to spot the animals, environments and recognition of the major threats to the species. The displacements along the study area were performed by a 4x4 Toyota Bandeirante, called "Igarakuê." After 16 months of activities, the mobile unit "Igarakuê" had travelled almost all the villages and coastal regions of seven northeastern states (Sergipe, Alagoas, Pernambuco, Paraiba, Rio Grande do Norte, Ceará and Piauí), with 552 interviews conducted in 199 locations . Worryingly it was observed the disappearance of the species in the Sergipe State, the isolation of populations present in the Alagoas State and the presence of discontinuous areas along the distribution in other states. The estimated abundance for the study area, with the minimum number of 117 specimens and a maximum of 242 specimens, where data showed a decrease in the total number of manatees sighted in recent decades. The marine environment has been indicated as the site of highest number of sightings and it was observed in the northeastern coastal region the presence of habitats favorable to the occurrence of the species. However, the siltation of rivers and bars, the rectification of river beds for agricultural purposes, deforestation of mangroves, pollution of water resources are some of the factors noted that compromise threatens habitats of manatees and sea irreversibly therefore the species. The harpoon was the main form of capture recorded in the history of hunting, but has not been widely used. The mortality of the animals is linked to events surrounding the stranding of puppies, accidental capture in fishing nets and stalls, hauls made by motorized boats and the use of explosives in fishing activities. From the results obtained, it is recommended the continuation of awareness campaigns along the northeast coast, the monitoring in the main areas of occurrence, the creation of protected areas, environmental education and the inclusion of sites with the highest occurrence of manatees and marine priority areas in the National Plan of Coastal Management.
KEYWORDS: Sirenia; Abundance; Factors of Threat; Mortality; Igarakuê.
LEVANTAMENTO DA DISTRIBUIÇÃO, OCORRÊNCIA E STATUS DE CONSERVAÇÃO DO PEIXE-BOI MARINHO (Trichechus manatus, Linnaeus, 1758) NO LITORAL
NORDESTE DO BRASIL RESUMO
No início da década de 80 foi realizado o primeiro levantamento sobre a distribuição dos peixes-boi marinhos no Brasil, o qual apontou o litoral Norte e Nordeste como áreas de ocorrência da espécie, sendo registrado o seu desaparecimento nos estados do Espírito Santo e Bahia. Considerando a ausência de dados recentes, este trabalho teve como objetivo atualizar as informações existentes sobre a distribuição e áreas de ocorrência do Trichechus manatus no litoral Nordeste brasileiro, bem como avaliar o status de conservação da espécie, visando subsidiar os trabalhos de preservação deste sirênio. O levantamento foi efetuado durante os anos de 1990 e 1991, do litoral de Sergipe até o Piauí. Utilizou-se um questionário contendo oito perguntas, sendo este direcionado aos pescadores. Quando constatada a importância da localidade para a ocorrência do peixe-boi marinho, foram realizadas incursões náuticas com o intuito de avistar os animais, reconhecimento dos ambientes e principais ameaças à espécie. Os deslocamentos ao longo da área de estudo foram realizados por meio de uma Toyota Bandeirante 4x4, denominada “Igarakuê”. Após 16 meses de atividades, a unidade móvel “Igarakuê” percorreu praticamente todas as vilas e localidades costeiras de sete estados Nordestinos (Sergipe, Alagoas, Pernambuco, Paraíba, Rio Grande do Norte, Ceará e Piauí), sendo realizadas 552 entrevistas em 199 localidades. De forma preocupante constatou-se o desaparecimento da espécie no estado de Sergipe, o isolamento das populações presentes no estado de Alagoas e a presença de áreas descontínuas ao longo da distribuição nos demais estados. Foi estimada a abundância para a área de estudo, com o número mínimo de 117 espécimes e um número máximo de 242 espécimes, onde as informações evidenciaram um decréscimo no número total de peixes-boi avistados nas últimas décadas. O ambiente marinho foi indicado como o local de maior número de avistagens e observou-se na região costeira nordestina a presença de habitats favoráveis a ocorrência da espécie. Entretanto, o assoreamento de rios e barras, a retificação do leito dos rios para fins agrícolas, o desmatamento de manguezais, a poluição dos recursos hídricos, são alguns dos fatores de ameaça constatados que comprometem os habitats dos peixes-boi marinhos de forma irreversível e consequentemente a espécie. O arpão foi a principal forma de captura registrada no histórico de caça, porém não vem sendo mais utilizado. A mortalidade dos animais tem ainda uma relação com eventos envolvendo o encalhe de filhotes, a captura acidental em currais e redes de pesca, arrastos realizados por embarcações motorizadas e o uso de explosivos nas atividades de pesca. A partir dos resultados obtidos, recomenda-se a continuidade das campanhas de conscientização ao longo do litoral nordeste, o monitoramento nas principais áreas de ocorrência da espécie, a criação de unidades de conservação, ações de educação ambiental e a inclusão dos locais de maior ocorrência dos peixes-boi marinhos como áreas prioritárias no Plano Nacional de Gerenciamento Costeiro.
PALAVRAS-CHAVE: Sirênios; Abundância; Fatores de ameaça; Mortalidade; Igarakuê.
v.1, n.2, august, 2011.
ISSN 2237‐9290
Section: Articles
Theme: Aquatic Megafauna
DOI: 10.6008/ESS2237‐9290.2011.002.0012
Régis Pinto de LIMA
http://lattes.cnpq.br/5149180797409019 regispintolima@gmail.comDanielle PALUDO
http://lattes.cnpq.br/7617645119170669 danielle.paludo@icmbio.gov.brRicardo José SOAVINSKI
ricardo.soavinski@icmbio.gov.brKleber Grubel da SILVA
http://lattes.cnpq.br/6508024149816895 nema@nema‐rs.org.brEunice Maria Almeida de
OLIVEIRA
eunice.oliveira@icmbio.gov.brPublished: 1992 Originally published: LIMA, R. P.; PALUDO, D.; SOAVINSKI, R. J.; SILVA, K. G.; OLIVEIRA, E. M. A.. Levantamento da distribuição, ocorrência e status de conservação do Peixe‐Boi Marinho (Trichechus manatus, Linnaeus, 1758) no litoral nordeste do Brasil. Peixe‐ Boi, João Pessoa, v.1, n.1, p.47‐72, 1992. Referencing well: LIMA, R. P.; PALUDO, D.; SOAVINSKI, R. J.; SILVA, K. G.; OLIVEIRA, E. M. A.. Survey of the manatee´s (Trichechus manatus, Linnaeus, 1758) distribution, occurrence and status of conservation in the northeast coast of Brazil. Natural Resources, Aquidabã, v.1, n.2, p.94‐110, 2011.
INTRODUCTION
Few are the information about the distribution and current conservation status of the sirenians in Brazil. Banks da Rocha (1971a, 1971b) recorded the occurrence of the marine manatee Trichechus manatus in the Sergipe, Alagoas, Pernambuco and Paraíba States, in the Brazilian northeastern. Whitehead (1978), based on the historical records, pointed out the Orange Cable (4°25’N) and the south of the Espírito Santo State (20°S) as limits of the distribution of the
Trichechus manatus in Brazil. He still pointed out that the few recent records indicate the rarity or
the absence of the marine manatee in the coastal areas when lived in the past (WITHEHEAD, 1978).
The last broad survey about the marine manatee distribution in the Brazilian coast was conducted in 1980 by Albuquerque and Marcovaldi, of the Instituto Brasileiro de Desenvolvimento
Florestal (IBDF), today Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis (IBAMA). The result of this work pointed out the Brazilian north and northeast coast as occurrence
areas of the T. manatus, recording its disappearing in the Espírito Santo and Bahia States (ALBUQUERQUE; MARCOVALDI, 1982).
The present work refers to an extensive survey conducted during 1990 and 1991 in the coastal side of the Sergipe, Alagoas, Pernambuco, Paraíba, Rio Grande do Norte, Ceará and Piauí States, which aimed to update the existing information about the distribution and occurrence areas of the Trichechus manatus in the Brazilian northeastern coast, as also to evaluate the status of the species conservation, intending to subside the works of this sirenian preservation.
METODOLOGY
During the preparation and execution of this work, some important aspects were considered: the marine manatee, one mammal species exclusively aquatic, very difficult to study and observe; the few information in Brazil about its distribution, occurrence and status of that species conservation; the coverage of the study area; the reduced number of the manatees in this area, so by Albuquerque and Marcovaldi (1982).
From these considerations, the information collected from Albuquerque and Marcovaldi (1982) were taken as references to delimit the area of study (northeast region), since the estuary formed by the Fundo, Real and Piauí Rivers, in the borders of the Bahia and Sergipe States, until the Parnaíba River, the Piauí and Maranhão states border. Hence, the species´ disappearing in the Espírito Santo and Bahia States was considered, region of Southern distribution of the T. manatus, according Whitehead (1978). The coast of the Maranhão State was included in the region due to its similarity with the Pará and Amapá coasts (north region).
In order to supply the considered areas which have no information by Albuquerque and Marcovaldi (1982), it was decided to conduct a detailed survey of the northeastern coast, that is, to investigate all the villages and coastal communities, through one “Mobile Unit”.
It was applied a simple questionnaire with eight basic questions, as a method of study to obtain data, to be developed by the fishermen with most chances to view or know the manatee. It was considered the coverage of their fishing arts, the fishing frequency, ages and in situ, the indications from other fishermen or people from the communities, to that. A report with the main environmental characteristics of the visited places, including the detected environmental impacts, was daily filled.
A Bandeirante Toyota 4x4 pickup truck was used to serve as a mobile unit, named ‘Igarakuê’. Geographic maps showing road systems, topographic maps from SUDENE and nautical charts form the Ministry of the Navy were acquired to guide the trip route, which had as the departure point the coast of the border of the Bahia and Sergipe States. The expedition always had its route south-north unchanged. In this way, all the information collected at the place was utilized and the information given in the locations previously visited were checked.
During the development of this study, the fishermen gathered in any fishing activity were fetched. Many times, the interviews were taken in the fishermen´s houses, but generally, done in the beach or by the rivers and estuaries margins.
It was utilized as a criteria the affirmative answer to the question “Do you know the marine manatee?” to verify the distribution and the occurrences of the animal, from the interviews. It was considered the information procedure, and, when the inhabitants knew the manatee in another region, the information was recorded for future verification. The sightings in the last 5 years were considered as actual occurrences, and the sightings from anterior periods, as historical occurrences. Among the oldest respondents, with 60 to 80 years old, it was possible to obtain information from 60 years ago and, indirectly, from dead friends´ relatives, information which dates back the beginning of the century. Therefore, material of osteology, harpoons, leather, fat and old photographs completed the information.
When the importance of the location during the occurrence of the manatee was confirmed, local fishermen´s canoe, boat or raft were rented to go on field outings, trying to sight animals, with the support of binoculars, and, to recognize the environments, feeding origins and main threats to the species. It was also used free diving in these occasions. In processing the data of the interview and of environmental reports and field the DBASE III PLUS program for database management was used.
RESULTS AND ARGUMENTS
The mobile unit Igarakuê travelled almost all the villages and coastal locations of the seven northeastern States (Table 1). From January, 1990, 16 months of working were done.
The objective of this detailed survey was to rescue value information about marine manatees, empirically recorded by fishermen´s generations.
Table 1: Coverage and effort of the field survey along the northeast coast.
STATE NUMBER OF INTERVIEWS NUMBER OF LOCATIONS COAST EXTENSION
PI 16 06 66 km CE 133 55 573 km RN 167 47 399 km PB 36 19 117 km PE 100 29 187 km AL 91 34 229 km SE 09 09 163 km TOTAL 552 199 1734 km
Distribution and Occurrence
The figure 01 depicts the results from the collected information (interviews and field outings) about the current areas of marine manatee occurrence in the northeast coast in Brazil.
Figure 1 – Distribution of the marine manatee (Trichechus manatus) along the northeast coast in Brazil,
according to interviews with fishermen.
The occurrence area and the number of manatees are diminishing. The species have already disappeared in the coasts of Espírito Santo and Bahia (Albuquerque and Marcovaldi, 1982). Through this work, it was confirmed the disappearing of the species in the coast of Sergipe, pointing it out as the south limit of the T. manatus occurrence (ALBUQUERQUE; MARCOVALDI, 1982). One last sighting by one fisherman resident in the location “Manatee”, at the margins of the Fundo River and distant 25 km from the mouth of the sea, was one solitaire individual, in the summer of 1985. In this way, the southern occurrence of the species is the coastal region of Pontal do Peba, Alagoas.
AREA OF DISTRIBUTION VISITED LOCATIONS
The isolation of the manatees´ groups in the coast of Alagoas, due to the species´ current absence in the south coast of the Pernambuco State to the proximity to Recife and Olinda. In this coast, therefore the existing locations with potentially using habitats for the manatees, like the Formoso River, Carneiros Beach, Tamandaré and São José da Coroa Grande, the manatee is considered an animal unknown by the current and older fishermen.
The results obtained confirm the quote for the coast of Brazil (ALBUQUERQUE, MARCOVALDI, 1982; LEFEBVRE et al., 1989) about one disjunction in the distribution of the marine manatee in the northeast coast, being confirmed that this discontinuity exists for at least six decades.
Absence sites and occurrence discontinuity of the species reinforce the hypotheses that manatees don´t do great migrations along the northeastern coast. The fishermen tell terms like “travelling” to describe the manatees´ displacements, short and regular, to feeding (for the stones and submerged reefs or submerged grass banks) and searching for fresh waters to drink, like rivers mouths, maceiós and waterholes.
The seasonal variations of the environment temperature seem not to be linked to the distribution of the manatees in this coast, as cited for the same species in the coast of Florida, EUA (MOORE, 1951; HARTMAMM, 1974), since this variation is less significant for the Brazilian northeast.
The figures 2, 3, 4, 5, 6 and 7 and tables 2, 3, 4, 5, 6, 7 present more details of the maps of the Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco and Alagoas States, respectively, indicating the visited locations, locations of the occurrence, maximum and minimum of current seen animals per location, according to interviews with fishermen.
Figure 2: Detail of the coast of Piauí, indicating the visited locations, occurrence locations, maximum and
Table 2: Places of the occurrence of the marine manatee in the Piauí state, with the maximum and minimum
of sighted animals per groups in the last 5 years, according to interviews with fishermen.
Occurrence localities (Maximum; Minimum)
Tatus (2; 1)
Pedra do Sal (2; 1)
Coqueiro (4; 1)
Barra Grande (2; 1)
Cajueiro da Praia (3; 1)
Figure 3: Detail of the coast of Ceará, indicating the visited locations, occurrence locations, maximum and
minimum number of current sighted animals per location, according to interviews with fishermen.
Table 3: Places of occurrence of the marine manatee in the Ceará State, with the maximum and minimum
number of sighted animals per group, in the last 5 years, according to interviews with fishermen.
Occurrence localities (Maximum; Minimum)
Bitupitá (2; 1) Guriú (1; 1) Cacimbinhas (1; 1) Barro Preto (1; 1) Morro Branco (1; 1) Bar of Sucatinga (3; 1) Cento Verde/Paripueira (1; 1) Canoa Quebrada (3; 1) Majorlândia (1; 1) Quixadá (1; 1) Fontainha (1; 1) Retirinho (2; 1) Ponta Grossa (2; 1) Icapuí (2; 2) Quitéria (2; 1) Tremembé (1; 1)
Figure 4: Detail of the coast of Rio Grande do Norte, indicating the visited locations, occurrence locations,
maximum and minimum number of current sighted animals per location, according to interviews fishermen.
Table 4: Places of the occurrence of the marine manatee in the Rio Grande do Norte State, with the
maximum and minimum number of sighted animals per group in the last 5 years, according to interviews with fishermen.
Occurrence localities (Maximum; Minimum)
Tibau (3; 1) Areias Brancas (2; 1) Upanema (2; 1) Ponta do Mel (1; 1) Rosado (5; 2) Porto do Mangue (1; 1) S. Bento do Norte/Caiçaras (1; 1) Morros (2; 1) Tourinhos (2; 1) São José (1; 1) Lagoa do Sal (2; 1) Touros (1; 1) Carnaubinhas (2; 1) Peroba (2; 1) Rio do Fogo (3; 1) Zumbi (6; 1) Bar of Punaú (2; 1) Maracajaú (2; 1) Caraúbas (3; 1) Bar of Maxaranguape (1; 1) Muriú (1; 1) Jacumã (6; 1) Pitangui (1; 1) Graçandu (5; 1) Bar of Rio (3; 1) Genipabu (4; 1) Redinha (2; 1) Ponta Negra (2; 1) Cotovelo (4; 1) Pirangi do Norte (6; 1) Pirangi do Sul (3; 1) Búzios (2; 1) Tabatinga (2; 1) Barreta/Camurupim (3; 1)
Tibau do Sul (8; 1)
Simbaúma (3; 1)
Bar of Cunhaú (2; 1)
Sagi (3; 1)
Figure 5: Detail of the Paraíba coast, indicating the visited locations, occurrence locations, maximum and
minimum number of current sighted animals per location, according to interviews with fishermen.
Table 5: Places of the occurrence of the marine manatee in the Paraíba state, with the maximum and
minimum number of the sighted animals per group, according to interviews with fishermen.
Occurrence localities (Maximum; Minimum)
Bar of Camaratuba (1; 1) Galego Beach (1; 1) Traíção Basin (1; 1) Coqueirinho (3; 1) Tramataia (1; 1) Bar of Mamanguape (5; 1)
Bar of the Miriri River (2; 1)
Lucena (2; 1) Poço Beach (3; 1) Penha/Ponta do Seixas (2; 1) Bar of Gramame/Mussumago (2; 1) Jacumã (2; 1) Bar of Abiaí/Pitimbu (2; 1) Pontinha/Acaú (4; 1) Congaçari (2; 1)
Figure 6: Detail of the Pernambucano coast, indicating the visited locations, occurrence locations, maximum
and minimum number of current sighted animals per location, according to interviews with fishermen.
Table 6: Places of the occurrence of the marine manatee in the Pernambuco State, with the maximum and
minimum number of sighted animals per group in the last 5 years, according to interviews with fishermen.
Occurrence localities (Maximum; Minimum)
Carne de Vaca (1; 1) Tabatinga Beach (2; 1) Ponta de Pedras (3; 1) Itamaracá Island (2; 1) Itapissuma (1; 1) Atapuz (1; 1) Maria Farinha (2; 1) Pau Amarelo (2; 1) Olinda (1; 1) Tamandaré (1; 1)
Figure 7: Detail of the Alagoano coast, indicating the occurrence locations, maximum and minimum number
of current sighted animals per location, according to interviews with fishermen.
Table 7: Places of occurrence of the marine manatee in the Alagoas State, with the maximum and minimum
number of sighted animals per group in the last 5 years, according to interviews with fishermen.
Occurrence localities (Maximum; Minimum)
Bar of Camaragibe (1; 1)
Bar of Santo Antônio (1; 1)
Tabuba (5; 3) Paripueira (4; 1) Sauaçui (2; 1) Ipioca (2; 1) Pescaria (3; 1) Riacho Doce (2; 1) Garça Torta (4; 1) Guaxumã (3; 2) Jacarecica (2; 2)
Cruz das Almas (5; 1)
Jatiúca (2; 1)
Francês Beach (4; 1)
Bar of São Miguel (2; 1)
Azeda Lagoon (1; 1) Bar of Jequiá (2; 1) Poxim (2; 1) Barreiras (1; 1) Miaí de Cima (1; 1) Pontal do Peba (2; 1)
The maximum and minimum number of seen animals per locality was used to determine the abundance of seen manatees in the area of study. So, as almost all the extension of the northeast coastal zone was verified, the sum of these numbers results in one minimum number of 117 and one maximum number of 242 individuals. It must be considered the probability of sightings of the same individuals in different localities, due to the species´ displacements. In this case, the number of current manatees in the northeast region of Brazil can be inferior to the obtained estimative.
The graphic 1 depicts the absolute sum of the maximum number of sighted animals in each locality of a state. The questions applied to fishermen who knew the manatee were: “How normally are the animals sighted?” “What is the higher number of animals you could see at the same time?” “Where?” “In old days, how many animals were normally sighted?” “When?”.
Graphic 1: Relationship between a number of manatees for the 60 years and for the last 5 years, according
to the fishermen´s records in the northeast coast of Brazil.
The information show a decrease in the total number of regular sighted manatees along the coast in the last decades, and the sightings frequency also diminished. The short coast of Piauí seems to keep a constant number of animals. This may be connected to the rarity of intentional deaths (the only one recorded where it was used a harpoon occurred almost fifteen years ago, and the hunter was from another locality), absence of puppies´ groundings and to the favorability of the coastal ecosystems to the species occurrence, that keep a good conservation state in that State.
The Sergipe, Pernambuco and Paraíba States are those which seem to present a more perceivable decrease to fishermen. The variation of the groups size (Graphic 2) represents the frequency of the answers to the question “How normally are the manatees?”.
TOTAL NUMBER OF MANATEES
STATES TOTAL NUMBER OF MANATEES IN 05 YEARS
Graphic 2: The size of the groups´ variation.
Solitary or paired animals are more frequently sighted (67%). It is common pairs formed by one big adult individual and one small individual, indicating one mother-puppy relationship. Few are the sites where nowadays the animals are sighted in groups, highlighting the estuary of the Mamanguape River, in Paraíba; the coastal Tibau do Sul, Rosado, Bar of Punaú, Graçandu, Pirangi and Sagi Lagoons, in Rio Grande do Norte, and Cajueiro da Praia, in Piauí. Among these, apenas na Barra de Mamanguape (PB) e em Cajueiro da Praia (PI), the manatees are normally sighted inside the estuaries only in the Bar of Mamanguape (PB) and in Cajueiro da Praia (PI).
Generally the fishermen did not define well the period the manatees are more common. Among the respondents, 41,60% say that it is in winter, relating that to the dirty waters, strong and constant wind; 40,20% believe it is in summer, clear and tranquil waters and 18,10% affirm that the manatees appear in equal period during all the year. It was observed that along the northeast coast the frequency of the sightings of manatees varies locally according to the year period, but the species presence is verified during all the year.
Habitat
The northeastern coastal zone presents many times a coast rugged by the presence of cliffs of the tertiary origin Formação Barreiras which appears from Rio de Janeiro to Amapá (Guerra, 1987). Characteristic are also the sandstone reefs beads, forming, in parallel with the coast, shallow and protected environments, known by fishermen as "the sea inside".
In Brazil is dominant the current (south branch of equatorial south stream) with direction SSW, water temperature between 24° C and 30° C, and a salinity exceeding of 36 ppm. Whitehead (1978) has proposed that temperature limits for t. manatus were situated between 24° C isotherms. Within this territory, the annual variation of the coastal waters temperature present low fluctuations, and the temperature can be considered almost constant, and favorable to the manatees´ occurrence.
THE SIZE OF THE GROUPS
The marine environment represents today where there is the major number of manatees sightings (78,42%) (Table 8). The northeastern coastal region offers favorable habitat to the manatees, because presents food, warm and shallow waters, refuges and a series of estuaries and basins, providing fresh waters fountains. Coastal communities wisdom says that the sighted manatees who appear inside or in the mouths of the rivers and other water bodies go there due to their need of “drinking” or “playing” with the fresh waters. However, with the great majority of the manatees currently living in the marine environment and its access to the fresh water bodies interior restricted to some long rivers, also undermined due to other impacting ways that harm the species penetration, the hypotheses that the manatees need fresh water to supply any physiological need becomes not so consistent, considering the current reality of the species´ occurrences.
Table 8: Proportion between the marine, estuary and fluvial environments, where the manatees are currently
sighted by fishermen in the northeast coast of Brazil.
MARINE ENVIRONMENT 78,4%
ESTUARY ENVIRONMENT 13,3%
FLUVIAL ENVIRONMENT 7,9%
Many fishermen affirm that the manatees, which today are sighted along the beaches and reefs, frequently entered the bars and estuaries. Analyzing the current state of conservation of the rivers and estuaries of the northeast region, from the recorded data of the environmental reports, the process of the rivers and bars aggradation is perceivable. The deforestation of hillsides and the expansion of monoculture agroindustry cause soil erosion; the straightening of the river bed for agricultural purposes, the deforestation of mangroves, as well as pollution by agrochemicals, undermined this environment irreversibly. It is cited the presence of manatees only in tides favorable for their getting in and posterior getting out, in some bars of rivers and estuaries. In other places, they are sighted proximate to mouths of water bodies, but the interior access is undermined due to the low depth of the bar and the grounding threaten (for example, the bars of the Guaju, RN, Abiaí, PB and Sapucaí, AL rivers).
Another important factor that probably makes the manatee flee from the estuaries environment and the river is the concentration of motor boats at the margins, compounding improvised fishing ports.
The extensive sandstone cord parallel to the coast has important function for the manatee in that coast. It provides substrate for marine algae (food) and corridors for displacements from one side to another (protection). The reefs create an environment of shallow, calm and warm waters, where the marine phanerogamic banks are common, highlighting the needle grass (Halodule sp), main food found inside the digestive tract of dead animals rescued by the Programa de Recuperação de Carcaças do Centro Peixe-Boi (Manatee Center, non-published data). In these places, the animals are easily sighted by the people in the beach, because, during their feeding, frequently expose the back or the tail on the surface.
Precious information from 25 manatees´ hunters along the northeast coast was rescued. Many other famous fishermen had already died. The graphic 3 depicts the cases of captures divided into seven main occurrence types.
Graphic 3: Capture and mortality of the marine manatee along the northeast coast, according to records
from fishermen in the last 60 years.
Along a historical evolution of the arts of marine manatee capture, it is observed that hunting with harpoon, main way of the species capture, practically does not happen in the north east coast anymore. The reason alleged by the hunters yet alive is the children´s lack of interest about manatee hunting, mainly due to the difficulty of finding it today. Moreover, the need the fisherman had to have much patient and courage to harpoon a strong and big animal discourage him for hunting. The main localities where typical marine manatees were found are: Fundo River/SE, Pajuçara – Maceió/AL, Ipioca/AL, Goiana River/PB, Abiaí River/PB, Bar of the Mamanguape River/PB and Bar of Cunhaú/RN.
All the manatees´ deaths caused by bombs were intentional and recorded only in the South coast of Rio Grande do Norte, all of them more than 20 years ago. In Bar of Cunhaú, RN, the manatees, currently, are only sighted outside of the reefs, passing in front of the mouth of the river. The last three manatees sighted inside the river were dead by a fisherman using one piece of dynamite, and, since then, the animals have not entered into the river anymore.
The corrals, arts of fishing by trap, in their majority were disabled in the northeast coast, excepting in the Ceará and Pernambuco coast. Inside this trap, generally, the animals get into when are eating algae fixed to the wooden parts of the corral, being accidently prisoned and are killed clubbed or stabbed, intentionally
Currently, in the northeast coast, the main causes for deaths and captures of the marine manatee are due to the constant presence of nylon nets, the gill nets (caçoá, caçoeira) as also the drag nets (tresmalho, camaroneira). In the cases of the gillnets, the majority of the animals die drowned and, in the drag nets, are taken inside them to the beach (tresmalho) or to the boat (camaroneiras) or clubbed, stabbed or shot.
7,5% BOMB 8,5% DRAGGINGS 9% CORRAL 12% GILLNETS 12% UNDETERMINED 17% PUPPIES´ GROUNDINGS 34% HARPOON
The improvement of the nylon nets in the northeast coast occurred in the last two decades and has been advancing yearly, becoming common gill nets put across to channels, camboas and strips between the reefs, places where the manatees go to. In a recent work (Oliveira et al, in press), it is described that the intentional and accidental captures by gillnet and drag nets are the main the current causes of the species mortality in this coast. Motorized boats, mainly shrimp drags, when illegally invade the three miles of small fishing protection, make them flee or capture the manatees, being confirmed one adult death on February, 1990, in Lucena, PB. In this same beach, drag small fishermen, aware, have already accidentally captured 3 manatees, freeing them immediately (Manatee Center, non-published data).
The undetermined deaths are those connected to groundings or when dead adult animals appear. Depending on the carcase conservation state, the fishermen take advantage of the meat and the fat.
One important fact recorded in this survey was the occurrence of grounded newborn puppies, with length between 1,20 and 1,40 m, characterized by dark skin, remains of umbilical cord and folds in the abdomen. As immediate result from the mobile unit Igarakuê, the puppies grounded between December, 1990 and April, 1991 were rescued by aware fishermen and transported by the Manatee Center/IBAMA, where were recovered. Three of these puppies grounded in the south coast of Ceará, and another in the north coast of Rio Grande do Norte. Among the 43 cases of grounded puppies recorded during the survey, 33 (79,07%) are located between the south portion of the Ceará State (20 cases) and the north of the Rio Grande do Norte State (13 cases). This is the most important occurrence area of puppies´ grounding in all studied area. It is also a continuous occurrence area of the species in the coast, and in the RN State, where there are the large number of animals´ sightings, when almost the total number is sighted in marine environment.
The rivers, bars and estuaries of this grounding region are found silted, decharacterized by the saline formations and taken by motorized lobstermen boats and urban settlements (Areia Branca, Macau, Galinhos and Guamaré, in RN and Ipucai, in CE). Considering that these protected estuary environments represent refuge for females and puppies, and that the puppies rescued by the Manatee Center were found in non-protected beaches and the physical conditions was good, it can be suggested the hypotheses that when the females from that region when don´t find safe refuge for them to give birth and to raise their puppies, are obliged to face the first days after birth in no ideal conditions to the puppy´s adaptation in the environment, occurring, many times, the loss or the loss and abandon of the puppy.
CONCLUSIONS
A partir dos resultados deste trabalho, recomenda-se a continuidade das campanhas de conscientização ao longo do litoral nordeste; a realização de estudos e monitoramento nas localidades indicadas como as principais áreas de ocorrência da espécie no nordeste; a criação e implantação de unidade de conservação em áreas prioritárias para a preservação dos peixes-boi, tais como o estuário formado pelos rios Ubatuba e Timonha e costa adjacente, na divisa do Piauí e Ceará; desenvolvimento de programas de educação ambiental junto as áreas de maior ocorrência visando a proteção efetiva do peixe-boi e a conservação dos ecossistemas locais; inclusão destas áreas prioritárias no Plano Nacional e Gerenciamento Costeiro e nos planos de desenvolvimento a nível Federal, Estadual e Municipal.
ACKNOWLEDGEMENTS
To the fishermen, with no collaboration this work would not have been developed, to the functionaries of the manatee Center/IBAMA, especially Mr. Márcio Sergio Formiga and Evandro Gomes da Silva who very committed to make the mobile unit a reality, to the functionaries of the state superintendencies of IBAMA, to the oceanographer Regis Muller and to Adriano Py Chludinsky for his effort and dedication in this work.
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