Biologia populacional de Callichirus major (Say, 1818) (Crustacea: Axiidea: Callianassidae), nas praias de Santos e São Vicente, litoral centro do Estado de São Paulo, Brasil: subsídios para conservação e manejo
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2017-01-17
Autores
Hereman, Michael José [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
As praias de Santos (SP) apresentam legislação municipal de proibição de captura das espécies de Callianassidae, p ex. Callichirus major (Lei Municipal nº 1.293/93), fato este não verificado em municípios limítrofes, como São Vicente. Esta legislação foi decorrente de um amplo estudo de 10 anos (1983 a 1993), desde então não existindo outros mais aprofundados sobre a biologia populacional desta espécie. Portanto, a presente dissertação tem como objetivos realizar uma avaliação comparativa da biologia populacional de Callichirus major entre a praia do Gonzaga, localizada no Município de Santos (protegida) e a praia do Itararé, no Município de São Vicente (sem legislação pertinente à captura da espécie). O primeiro objetivo foi efetuar um teste de tamanho do quadrado ideal para as amostragens, através do método de Wigert (W), assim como o número de réplicas por subárea amostral, determinada pela estabilização das variâncias (V), indicando um mínimo ideal de 50 réplicas (V=24,6). O possível efeito da declividade e distância do mar sobre os parâmetros populacionais da espécie foi também testado em duas transecções de quadrados amostrais contíguos (vertical e paralela à linha de costa). Com base nos resultados obtidos, foi estabelecido o número de subáreas amostrais em cada praia, levando-se em conta sua extensão (Praia do Itararé: 2,3 km; e Praia de Santos: 4,7 km). A densidade foi maior nas transecções próximas aos canais (5,0 ± 1,6 e 4,5 ± 2,0 ind./m2) do que aquela mais equidistante (F = 13,20; p = 0,000), indicando para evitar áreas de canal próximas para minimizar o viés amostral durante as análises espaciais. Nas duas praias foram contabilizadas as galerias da espécie por quadrado amostral, a fim de comparar as condições de distribuição destes organismos de maneira particular nestas praias, e seus dados inseridos em planilhas eletrônicas, perfazendo o segundo objetivo do estudo. Em outra subárea, em ambas as áreas de estudo (Gonzaga e Itararé), exemplares de C. major foram coletatos a utilização com uma bomba sugadora em PVC, para cumprir o terceiro objetivo, o qual consistiu de registrar informações biométricas e reprodutivas, para caracterizar a população diante da pressão de pesca, ou diante de condições de proibição da captura. A densidade da espécie foi registrada pelo número de indivíduos/m2 e comparadas entre as praias através de um teste de GLM (modelos lineares generalizados), usando como variáveis explicativas o local, mês e o estirâncio. Os resultados indicaram que a densidade anual no município de Santos (STS = 6,8±3,3 galerias/m2) foi 2,5 vezes superior àquela registrada em São Vicente (SAV = 2,7±2,5 galerias/m2). A estrutura populacional foi avaliada pela distribuição dos exemplares de cada sexo em classes de tamanho (CC) de 1 mm e a razão sexual pela proporção macho:fêmea. Para isto, comparou-se a média do CC de machos e fêmeas usando um t-test ou U de Mann-Whitney, dependendo se a distribuição dos dados foi normal ou não. Durante o referido período de amostragens, um total de 546 espécimes de Callichirus major (204 machos, 342 fêmeas) na praia do Gonzaga e 404 (217 machos, 187 fêmeas) em Itararé, respectivamente. Em relação ao tamanho de CC, as fêmeas foram significativamente maiores em ambas as praias, 17,1 ± 1,92 mm (Gonzaga) e 16,5 ± 2,07 mm (Itararé), em relação aos machos 15,0 ± 2,83 e 15,0 ± 2,66, respectivamente. Contudo, este estudo provou a eficiência da legislação de proteção de C. major no Município de Santos, para as praias de São Vicente e outros municípios do estado de São Paulo, e demais locais do Brasil, com fins de contribuir com o manejo e conservação desta espécie, e ainda, ressaltou a importância de outros estudos aliados à exploração sustentável deste recurso.
The C. major from Santos (SP) are protected by law (municipal law number 1.293/93) so, it´s prohibited to capture this crustacean from the beaches, this fact isn´t verified at boundaries counties, just like São Vicente, for example. This legislation was due a great study during 10 years (1983 to 1993), since then, doesn´t exist other importants studies about this specie. Therefore, this present dissertation aims to realize a comparative avaliation of the populational biology of Callichirus major between Gonzaga beach (Santos, SP), a protected area, and Itararé beach (São Vicente, SP). The first objective was realize a test to obtain a optimiun quadrat size for the sampling, using the Wigert (W) method, as well as the number of replicates per sample areas, determinate by the stabilization of variances (V), indicating a minimum of 50 replicas (V=24,6). The possible effect of declivity and sea´s distance were evaluated too, using for this, two transections of contiguous sample quadrat (vertical and parallel to the coast line), the one with less variance of sazonal and temporal analyzes was chosen. Based in the obtained results, a number of sample areas were established, taking into account the beaches´s extension (Itararé´s beach: 2,3km; Santos´s beach: 4,7 km). The density was bigger at the transections near the channels (5,0 ± 1,6 e 4,5 ± 2,0 ind./m2) then the equidistant one (F = 13,20; p = 0,000), indicating to avoid nearby channels areas to minimize the sampling bias during the spatial analyzes. In both beaches the species´s galleries per sample quadrat were calculated, in order to compare the distribution conditions of this animal particularly at these beaches, and the respective data inserted in eletronics spreadsheets, reaching the second objective os this study. In other subarea, at both beaches (Gonzaga e Itararé), specimens of C. major were collected, using for this a manual pump made by PVC, to fulfill the third objective, that consisted in register the biometrical and breeding cycle informations, to characterize the population in front of the fishing pressure, or in front of prohibition capture conditions. The species density were registered by the number of individuals/ m2 and compared between the two beaches through a GLM test (Generalized Linear Model), using as explanatory variables the place, month and the foreshore. The results indicated that the annual density of Santos city (STS = 6,8±3,3 galleries/m2) was 2,5 times superior than the records from São Vicente (SAV = 2,7±2,5 galleries/m2). The population structure was evaluated by the specimens distribution of each sex in size classes of 1mm and the sex ratio by the proportion male: female. For this, the cephalothoracic length (CL) between males and females were compared, using a t-test or U of Mann-Whitney, being the data distribution normal or not. During the sampling period, a total of 546 specimens of Callichirus major (204 males, 342 females) were collected in Gonzaga beach and 404 (217 males, 187 females) in Itararé. Related to the CL size, the females were significantly higher on both beaches, 17,1 ± 1,92 mm (Gonzaga) and 16,5 ± 2,07 mm (Itararé), in relation to males 15,0 ± 2,83 e 15,0 ± 2,66, respectively. However, this study proved the efficiency of the C. major protection legislation in the city of Santos, of population control to the beaches of São Vicente and other cities from São Paulo state, and to other places in Brazil, in order to contribute with the management and conservation of the specie, emphasizing the importance of other allied studies to the sustainable exploitation of this resource.
The C. major from Santos (SP) are protected by law (municipal law number 1.293/93) so, it´s prohibited to capture this crustacean from the beaches, this fact isn´t verified at boundaries counties, just like São Vicente, for example. This legislation was due a great study during 10 years (1983 to 1993), since then, doesn´t exist other importants studies about this specie. Therefore, this present dissertation aims to realize a comparative avaliation of the populational biology of Callichirus major between Gonzaga beach (Santos, SP), a protected area, and Itararé beach (São Vicente, SP). The first objective was realize a test to obtain a optimiun quadrat size for the sampling, using the Wigert (W) method, as well as the number of replicates per sample areas, determinate by the stabilization of variances (V), indicating a minimum of 50 replicas (V=24,6). The possible effect of declivity and sea´s distance were evaluated too, using for this, two transections of contiguous sample quadrat (vertical and parallel to the coast line), the one with less variance of sazonal and temporal analyzes was chosen. Based in the obtained results, a number of sample areas were established, taking into account the beaches´s extension (Itararé´s beach: 2,3km; Santos´s beach: 4,7 km). The density was bigger at the transections near the channels (5,0 ± 1,6 e 4,5 ± 2,0 ind./m2) then the equidistant one (F = 13,20; p = 0,000), indicating to avoid nearby channels areas to minimize the sampling bias during the spatial analyzes. In both beaches the species´s galleries per sample quadrat were calculated, in order to compare the distribution conditions of this animal particularly at these beaches, and the respective data inserted in eletronics spreadsheets, reaching the second objective os this study. In other subarea, at both beaches (Gonzaga e Itararé), specimens of C. major were collected, using for this a manual pump made by PVC, to fulfill the third objective, that consisted in register the biometrical and breeding cycle informations, to characterize the population in front of the fishing pressure, or in front of prohibition capture conditions. The species density were registered by the number of individuals/ m2 and compared between the two beaches through a GLM test (Generalized Linear Model), using as explanatory variables the place, month and the foreshore. The results indicated that the annual density of Santos city (STS = 6,8±3,3 galleries/m2) was 2,5 times superior than the records from São Vicente (SAV = 2,7±2,5 galleries/m2). The population structure was evaluated by the specimens distribution of each sex in size classes of 1mm and the sex ratio by the proportion male: female. For this, the cephalothoracic length (CL) between males and females were compared, using a t-test or U of Mann-Whitney, being the data distribution normal or not. During the sampling period, a total of 546 specimens of Callichirus major (204 males, 342 females) were collected in Gonzaga beach and 404 (217 males, 187 females) in Itararé. Related to the CL size, the females were significantly higher on both beaches, 17,1 ± 1,92 mm (Gonzaga) and 16,5 ± 2,07 mm (Itararé), in relation to males 15,0 ± 2,83 e 15,0 ± 2,66, respectively. However, this study proved the efficiency of the C. major protection legislation in the city of Santos, of population control to the beaches of São Vicente and other cities from São Paulo state, and to other places in Brazil, in order to contribute with the management and conservation of the specie, emphasizing the importance of other allied studies to the sustainable exploitation of this resource.
Descrição
Palavras-chave
Camarões-fantasma, Densidade, Dimorfismo sexual, Estrutura populacional, Ciclo reprodutivo, Ghost-shrimp, Density, Sexual dimorphism, Population structure, Breeding cycle