Estudio poblacional del cangrejo Cronius ruber (Lamarck,1818) en la isla de Tenerife.

Cronius ruber es una especie de crustáceo que pertenece a la familia de los Portúnidos y de reciente aparición en las islas Canarias. Actualmente, este cangrejo es considerado como una posible especie invasora, dada la rápida expansión de sus poblaciones y su capacidad de depredación sobre otros organismos de los fondos rocosos someros de las islas. Sin embargo, son muy escasos los estudios que han abordado el tema. Es por ello que el objetivo de este trabajo fue registrar su abundancia en distintas localidades de la isla de Tenerife, estudiar su morfometría, determinar el estado de madurez sexual de machos y hembras y la dureza de su caparazón. Los resultados revelan que la mayor densidad de C. ruber registrada fue en Boca Cangrejo y Teno, predominando los machos en la mayoría de las localidades. El mayor tamaño de C. ruber se registró en Boca Cangrejo y Armeñime. Asimismo, se confirma un dimorfismo sexual relacionado con la anchura de caparazón y longitud de la pinza derecha, siendo los machos los que presentan un mayor tamaño de estas estructuras. C. ruber es fértil durante la mayor parte del año y el caparazón es duro en la mayoría de los casos. Todas estas son características que confirman su capacidad invasora en Canarias, donde se prevé un aumento drástico de su población debido a los ambientes favorables que encuentra en las islas.Cronius ruber is a crustacean species that belongs to the Portunid family that has recently appeared in the Canary Islands. Currently, this crab is considered a possible alien species, due to the fast expansion of its populations and its predatory ability against other organisms of the rocky reefs in these islands. Nevertheless, the studies treating this subject are scarce. For that reason, the aim of this research was to record its abundance in different Tenerife locations, to carry out a morphometric study, to determine the states of sexual maturity of male and female crabs and the hardness of its carapace. The results reveal that the highest density of C. ruber recorded was in Boca Cangrejo and Teno, with males predominating in most locations. The greater size of C. ruber was registered in Boca Cangrejo and Armeñime. In addition, a sexual dimorphism related to the width of the carapace and length of the right claw is confirmed, with males showing a larger size of these structures. C. ruber is fertile most of the year and its carapace is hard most of the cases. All these are characteristic that confirm its invasive capacity in the Canary Islands, where a drastic increase of its population is foreseen due to the favorable environments found in the islands

Comparative studies of the reproductive strategies of New Zealand grapsid crabs (Brachyura: Grapsidae) and the effects of parasites on their reproductive success.

The reproductive strategies of four intertidal grapsid crabs, Hemigrapsus sexdentatus, H. crenulatus, Cyclograpsus lavauxi, and Helice crassa, were studied in the field and laboratory, with emphasis on mating behaviour, duration of female receptivity, and sperm competition. Mating occurred in all species during the intermoult on the days prior to oviposition, when the gonopore opercula of females became temporarily mobile. Female Helice crassa mated up to three weeks after oviposition, but in all other species mating typically ceased at egg-laying. Male Hemigrapsus spp. used a female-centered competition strategy in which they searched for and defended receptive females until they laid eggs. In contrast, male C. lavauxi searched for and intercepted receptive females only for the duration of copulation and then pursued other receptive females (a mating system termed encounter rate competition with pure search and interception). Male Helice crassa searched for receptive females in their immediate neighbourhood and mated with them briefly on the substrate or in the burrow after which the female left (a mating system termed encounter rate competition with neighbourhoods of dominance). The mating season was short and highly synchronous for Hemigrapsus sexdentatus and Cyclograpsus lavauxi and asynchronous for Hemigrapsus crenulatus and Helice crassa. In the laboratory, the mean duration of receptivity for females housed with three males varied between 4.1 and 12.4 days, and the copulation frequency of females varied before oviposition between 2.1 and 24.3 times (mean) depending on the species. Female Hemigrapsus spp. Isolated from males stayed receptive significantly longer than females held continuously with males. This suggests that females are able to control the duration of their receptivity, and therefore the time available for mating, according to the absence or presence of males. The operational sex ratio (OSR) had no effect on the duration of female receptivity, but female Hemigrapsus crenulatus mated more often when several males were competing for access. Therefore, male-male competition increased the number of matings per female and hence sperm competition within the female spermathecae. Larger males mated significantly more often than smaller males in all species. However, male size did not affect ejaculate size, meaning that small and large males transferred similar-sized ejaculates, e.g., in Hemigrapsus spp. Males of the two Hemigrapsus species followed a different strategy of sperm allocation. Male H. crenulatus, which are typically confronted with a high mating frequency of the female and a long, asynchronous mating season, distributed similar-sized ejaculates, irrespective of female size. By contrast, male H. sexdentatus, which experience a comparatively lower risk of sperm competition during a short, synchronised mating season, invested larger ejaculates for larger females than for smaller females. In addition, the size of the first and second ejaculates transferred to a female by a male H. crenulatus were not significantly different, whereas the first was larger than the second for H. sexdentatus. A parasitological survey was undertaken of the four grapsid crabs and the presence, seasonal variation and relationship with host gender and size of parasites determined. Four internal parasites were discovered: Nectonema zealandica n. sp. (Nematomorpha: Nectonematoidea), Portunion sp. (Isopoda: Entoniscidae), Profilicollis novaezelandensis n. sp. and Profilicollis antarcticus (Acanthocephala: Polymorphidae). Portunion sp. castrated its female hosts, but not the males thereby creating a more male-biased sex ratio. Males parasitized with Portunion sp. were equally successful during male-male competition and the number of matings they achieved. The above findings are important for our current understanding of mating strategies in Grapsidae, which are more diverse than previously thought. Females with a restricted duration of sexual receptivity have some control over their receptive period and can therefore influence the OSR and the extent of male-male competition. As females mated multiple times during their receptive period, sperm competition is a common feature in Grapsidae. However, males employed different tactics in regards to sperm competition such as longer mating duration (e.g., C. lavauxi), high number of matings (Helice crassa), or post-copulatory mate guarding until oviposition (Hemigrapsus spp.)

Distribuição dos siris e biologia reprodutiva de Callinectes Danae Smith, 1869 (Decapoda, Portunidae) na Baía de Guaratuba e Área costeira adjacente, Paraná, Brasil

Orientadora : Profa. Dra. Setuko MasunariDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Zoologia. Defesa: Curitiba, 04/12/2009Bibliografia: fls.75-79Area de concentração: ZoologiaUm estudo sobre a distribuição espaço-temporal dos siris e dos parâmetros populacionais e da maturidade sexual de Callinectes danae foi realizado no interior da Baía de Guaratuba, PR (25°51’S-48°33’W e 25°52’S-48°43’W) e na área costeira adjacente. As coletas foram realizadas em três estações dentro da baía ao longo do gradiente crescente de salinidade (Ilha da Coroa Grande, Ilha do Araçá e Ilha da Sepultura) e numa quarta estação na região costeira adjacente (Morro do Cristo). As coletas ocorreram de fevereiro de 2008 a janeiro de 2009, com amostragens bimestrais do final do outono ao início da primavera e mensais do final da primavera até o início do outono. As amostragens no estuário foram efetuadas com espinhel de fundo artesanal e arrasto de gerival, enquanto na área costeira, com arrastos de fundo (malha de 2,5cm). Somente C. danae teve o sexo e os estágios de maturação morfológica e gonadal reconhecidos e as larguras da carapaça na base (LCB) e na ponta dos últimos espinhos laterais (LCE) medidas. A temperatura média mensal do ar na região de Guaratuba variou de 18,5 ºC (set/2008) a 24,9 ºC (fev/2008) e a precipitação de 23,2mm (jul/2008) a 685,6mm (nov/2008). No estuário, a salinidade variou de zero (Coroa Grande) a 35 (Sepultura), o oxigênio dissolvido de 4,6 a 11,5 mg.L-¹, e a profundidade de 1,78 a 6,48 m. No interior da baía, a salinidade e o oxigênio dissolvido no fundo variaram significativamente entre as estações de coleta, enquanto o oxigênio dissolvido e as temperaturas da água e do ar o fizeram entre os meses amostrados. Tanto no estuário como na região costeira, C. danae foi a espécie dominante (n=451); A. cribrarius ocorreu apenas no Morro do Cristo (n=11), C. bocourti (n=2) somente na Ilha da Coroa Grande e C. ornatus foi rara no estuário (n=1), porém a segunda espécie mais freqüente na área costeira (n=96). O número de indivíduos de C. danae foi menos abundante na estação de menor salinidade (Coroa Grande). Houve uma oscilação temporal acentuada dos portunídeos dentro da baía, de 4 (mai/2008) a 67 (mar/2008) siris, o que pode estar relacionado com a migração destes para locais específicos e com a alternância espacial e temporal gerada pela sobreposição de nichos das espécies dominantes. As variações da salinidade e da temperatura explicam melhor, respectivamente, a distribuição espacial e temporal dos siris no interior da baía e estão diretamente relacionadas com a precipitação, variável que mais influi na distribuição temporal dos mesmos na área costeira. Dos 451 espécimes de C. danae, 182 o foram no interior da baía e 269 na área costeira adjacente. O número total dos organismos desta espécie foi diretamente relacionado com a temperatura média mensal do ar. Machos predominaram no interior da baía, enquanto que fêmeas adultas e fêmeas ovígeras, na área costeira. Fêmeas não ocorreram na Ilha da Coroa Grande, machos adultos e fêmeas em tamanho de maturação foram mais freqüentes na Ilha do Araçá, juvenis constituíram a maioria na Ilha da Sepultura; na estação costeira, juvenis pequenos foram ausentes, mas houve dominância de fêmeas em estágio avançado de maturação gonadal e ovígeras. Machos apresentaram maior média de tamanho e maior classe modal do que as fêmeas. A maturidade morfológica de fêmeas foi estimada em 54,59mm LCB com o método da curva logística e em 54,37mm com o método do crescimento relativo, enquanto o tamanho em que ocorre a maturação gonadal de fêmeas foi de 55,45mm LCB. Para machos, estes valores foram ,respectivamente, 70,03, 68,86 e 71,15mm LCB. A população de C. danae na Baía de Guaratuba e adjacências apresenta um ciclo de vida com uma fase estuarina e outra costeira, cujos machos atingem maturidade sexual em tamanho superior ao das fêmeas e as maturidades sexuais morfológicas e gonadais, de ambos os sexos, ocorrem sincronicamente.A study on spatial and temporal distribution of swimming crabs and population parameters and the sexual maturity of the blue crab Callinectes danae was carried out in Guaratuba Bay, PR (25°51’S-48°33’W and 25°52’S-48°43’W) and adjacent coastal area. The samples were taken at three stations inside the bay along the gradient of increasing salinity (Coroa Grande Island, Araçá Island and Sepultura Island) and at a fourth station in the coastal area adjacent to the bay (Morro do Cristo). Crabs were collected from February 2008 to January 2009, with bimonthly sampling from the end of autumn to the early spring and monthly sampling from the late spring to the early autumn. They were obtained with baited bottom longlines (locally called "espinhel") and a handmade drag net (locally called "gerival") inside the bay, and with trawling by a professional fisherman in the adjacent coastal area. The monthly air temperature average in the Guaratuba municipality ranged from 18.5 º C (Sep/2008) to 24.9 º C (Feb/2008) and precipitation from 23.2 mm (Jul/2008) to 685.6 mm (Nov/2008 ). In the estuary the salinity varied from zero (Coroa Grande) to 35 (Sepultura), the dissolved oxygen from 4.6 to 11.5 mg.L-¹ and the station depth from 1.78 to 6.48 m. The crabs’ sex and stage of morphological and gonadal maturation were recognized of C. danae specimens and the carapace width between last lateral spines’ base (CWB) and between their tips (CWT) was measured too.The salinity and dissolved oxygen in the bottom varied significantly according to collection stations inside the bay, and the dissolved oxygen and air and water temperatures varied significantly in monthly samples. Callinectes danae was the dominant species (n=451), both in the estuary and in the coastal area; A. cribrarius occurred only in Morro do Cristo (n=11), C. bocourti only in Coroa Grande (n=2) and C. ornatus was rare in the estuary (n=1) but the second most frequent specie in the coastal area (n=96). The C. sapidus abundance did not differ significantly between the stations inside the estuary, while C. danae was less abundant in lower salinity waters (Coroa Grande). The portunids abundance widely oscillated inside the bay, from 4 (mai/2008) to 67 (mar/2008) crabs, and the highest values were recorded in warmer months, that may be related to the migration to specific sites or to the spatial and temporal differentiation on the species occupancy reported to the niches over lap. The spatial and temporal distribution of crabs inside the bay is better explained, respectively, by the oscillation of salinity and temperature, while the rainfall amount influences their temporal distribution in the coastal area. Were obtained 451 C. danae crabs, of which 182 inside of the bay and 269 in the adjacent coastal area. The oscillation of total abundance was directly related to the oscillation of monthly air temperature average. Males predominated inside the bay, whereas adult females (including ovigerous ones) in the coastal area. Females were absent in Coroa Grande Island, mature adults were more frequent in Araçá Island, juveniles constituted the majority in Sepultura Island, and in the coastal station, small juveniles were absent and females in advanced stages of gonadal maturation and ovigerous females dominated. Males had average size greater than females’. Females’ morphologic maturity was estimated in 54.59 mm CWB with the logistic curve method, and at 54.37 mm CWB with the relative growth method, while gonadal maturity was attained at 55.45 mm CWB. For males, these values were respectively 70.03, 68.86 and 71.15 mm CWB. The population of C. danae in Guaratuba Bay and adjacent area presents a life cycle with coastal and estuarine phases, where males attain sexual maturity in larger sizes than females, and both morphological and gonadal sexual maturities occur synchronously in males and females

The systematics of the crabs of the family varunidae (Brachyura, Decapoda)

Ph.DDOCTOR OF PHILOSOPH

Implicaciones de la composición bioquímica y la condición energética de la centolla, "Maja brachydactyla" (Balss, 1922), en su ciclo reproductivo

[Resumen] Esta tesis doctoral aborda el estudio de la biología reproductiva de Maja brachydactyla, centrándose en el ciclo reproductivo y el ciclo de cría a partir del análisis de las puestas y de las gónadas de las hembras, y su variabilidad en función de las condiciones ambientales. El análisis de la biología de M. brachydactyla, se realiza mediante una aproximación que integra aspectos morfológicos, biométricos, y bioquímicos, permitiendo obtener una imagen global sobre la inversión maternal y los requerimientos nutricionales necesarios para los procesos de maduración gonadal y de embriogénesis. Los resultados obtenidos demuestran la existencia de diferencias importantes en las características de las puestas que cada hembra puede realizar en un mismo ciclo reproductivo. Estas diferencias podrían ser la consecuencia de un acoplamiento entre la condición fisiológica de las hembras, determinada por las condiciones ambientales cambiantes a lo largo de cada ciclo reproductivo, y la inversión maternal en cada puesta que da lugar a diferencias globales en el peso de la puesta y la fecundidad, así como a diferencias de calidad en términos de las características biométricas y bioquímicas de los embriones.[Resumo] Esta tese doutoral aborda o estudio da bioloxía reprodutiva de Maja brachydactyla, centrándose no ciclo reprodutivo e o ciclo de cría a partir da análise das postas e das gónadas das femias, e a súa variabilidade en función das condicións ambientais. A análise da bioloxía de M. brachydactyla realízase mediante unha aproximación que integra aspectos morfolóxicos, biométricos e bioquímicos, permitindo obter unha imaxe global sobre a inversión maternal e os requirimentos nutricionais necesarios para os procesos de maduración gonadal e de embrioxenia. Os resultados obtidos demostran a existencia de diferenzas importantes nas características das postas que cada femia pode realizar nun mesmo ciclo reprodutivo. Estas diferenzas poderían ser a consecuencia dun axuste entre a condición fisiolóxica das femias, determinada polas condicións ambientais cambiantes ó longo de cada ciclo reprodutivo, e a inversión maternal en cada posta que da lugar a diferenzas globais no peso da posta e a fecundidade, así como a diferenzas de calidade en termos das características biométricas e bioquímicas dos embrións.[Abstract] This PhD Research Thesis addresses the study of reproductive biology of Maja brachydactyla, focussing on the reproductive cycle and the breeding cycle, based on the analysis of broods and female gonads, and their variability according to environmental conditions. Analysis of the biology of M. brachydactyla is carried out through an approach that integrates morphological, biometric and biochemical aspects, allowing to obtain a global view about the maternal investment and the nutritional requirements needed for the gonadal maturation processes and for the embryogenesis. The obtained results show the existence of important differences in the characteristics of the broods that each female can carry out in the same reproductive cycle. These differences could be the consequence of an adjustment between physiological condition of the females, determined by the changing environmental conditions over each reproductive cycle, and the maternal investment in each brood that leads to global differences in brood weight and fecundity, as well as qualitative differences in terms of biometric and biochemical characteristics of the embryos

Size at sexual maturity of female crabs Sesarma rectum Randall (Crustacea, Brachyura) and ontogenetic variations in the abdomen relative growth

Made available in DSpace on 2019-09-12T16:57:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2005The aim of the present study was to ascertain the size at sexual maturity in females of the crab Sesarma rectum Randall, 1840 by comparing gonadal maturity to morphologic maturity (using abdomen-width data). The relative growth of theabdomen was analysed for all growth phases (for each 3-mm carapace width sizeclass), and the slopes of the separate allometric relationships were comparedthrough analysis of covariance (ANCOVA) from log(e)-transformed datato detect changes in the level of allometry during ontogeny. The physiological size at maturity (gonadal criteria) was determined through a logistic curve,indicating the size at which 50% of females presented mature gonads (M-50 = 17.4 mm CW). The highest allometric levels occurred in growth phases 2 and 3 (body sizes ranging from 15 to 21 mm CW), indicating faster growth of the abdomen during those phases. Phases I (< 15 mm CW) and 4 and 5 (size classes above 21 mm CW) showed isometric growth. In the study area, a mangrove on the northern coast of the state of Sao Paulo, Brazil, individuals of S. rectum began to reach sexual maturity from 15 mm CW onward, when the slopes of the relationship of abdomen width to carapace width became positively allometric, indicating a differential growth rate. A gradual decrease in the slope, tending to isometry, Occurred during ontogeny, as the animals became larger (older)

Size at sexual maturity of female crabs Sesarma rectum Randall (Crustacea, Brachyura) and ontogenetic variations in the abdomen relative growth

The aim of the present study was to ascertain the size at sexual maturity in females of the crab Sesarma rectum Randall, 1840 by comparing gonadal maturity to morphologic maturity (using abdomen-width data). The relative growth of the abdomen was analysed for all growth phases (for each 3-mm carapace width size class), and the slopes of the separate allometric relationships were compared through analysis of covariance (ANCOVA) from log e-transformed data to detect changes in the level of allometry during ontogeny. The physiological size at maturity (gonadal criteria) was determined through a logistic curve, indicating the size at which 50% of females presented mature gonads (M50 = 17.4 mm CW). The highest allometric levels occurred in growth phases 2 and 3 (body sizes ranging from 15 to 21 mm CW), indicating faster growth of the abdomen during those phases. Phases 1 (< 15 mm CW) and 4 and 5 (size classes above 21 mm CW) showed isometric growth. In the study area, a mangrove on the northern coast of the state of São Paulo, Brazil, individuals of S. rectum began to reach sexual maturity from 15 mm CW onward, when the slopes of the relationship of abdomen width to carapace width became positively allometric, indicating a differential growth rate. A gradual decrease in the slope, tending to isometry, occurred during ontogeny, as the animals became larger (older).<br>O objetivo do presente estudo foi determinar o tamanho da maturidade sexual em fêmeas do caranguejo Sesarma rectum através de comparações da maturidade gonadal com a maturidade morfológica (usando dados da largura do abdômen). O crescimento relativo do abdômen foi analisado para todas as fases de crescimento (para cada classe de tamanho de 3 mm de largura de carapaça) e os coeficientes de regressão foram comparados para cada relação alométrica através de analises de covariância (ANCOVA) após transformação logarítmica dos dados, afim de detectar mudanças nos níveis da alometria ao longo da ontogenia. O tamanho da maturidade sexual fisiológica (critério gonadal) foi determinado através de uma curva logística, indicando o tamanho no qual 50% das fêmeas apresentaram gônadas maduras (M50 = 17.4 mm LC). Os maiores níveis alométricos ocorreram nas fases de crescimento 2 e 3 (tamanho de corpo variando de 15 a 21 mm LC), indicando acentuado crescimento do abdômen durante estas fases. Crescimento isométrico ocorreu nas fases 1 (< 15 mm LC) e fases 4 e 5 (classes de tamanho acima de 21 mm LC). No local de estudo, um manguezal localizado na costa norte do Estado de São Paulo, indivíduos fêmeas de S. rectum começam a atingir a maturidade sexual a partir de 15 mm de LC, quando os coeficientes de regressão das relações da largura do abdômen contra a largura da carapaça tornam-se positivamente alométricos, indicando taxa de crescimento diferencial. Uma gradual diminuição na inclinação da reta, tendendo a isometria, ocorre ao longo da ontogenia conforme as fêmeas tornam-se maiores (mais velhas)