Reproduction of Megapitaria squalida (Bivalvia: Veneridae) in the Southeast Gulf of California, Mexico / Reproducción de la almeja callista Megapitaria squalida (Bivalvia: Veneridae) en el sureste del Golfo de California, México

AbstractBivalves reproductive cycle varies according to the particular environmental conditions where they are found, and these reproductive details represent basic information for their capture, management and conservation strategies. With this objective, the reproductive cycle of the clam Megapitaria squalida, inhabiting the Southeast of the Gulf of California (Altata Bay, Sinaloa, Mexico), was studied using histology and changes in the number and size of oocytes, from June 2013 to June 2014. Histological analysis of the gonads showed spawning activity throughout the year, with two peaks. The first was registered in October and it was accompanied by the highest decrease of weight; the second was in February with the highest percentage of spawning population; besides, a resting period was observed in December. The sex-ratio (female:male) of the clam population was 1.08:1 (χ2 = 5.72, d.f. = 1, P < 0.05). Mean oocyte size and number were different (P < 0.05) among all sampling months and fluctuated from 34.6 ± 5.8 µm in June 2014, to 41.9 ± 6.8 µm in February 2014, and from 443.8 ± 424.5 in February 2014, to 1 214.4 ± 267.6 counted in April, respectively. With these results we suggest a protection season from October to November, when the most intense release of gametes occur in this population. Rev. Biol. Trop. 65 (3): 881-889. Epub 2017 September 01.

ResumenEl ciclo reproductivo de los bivalvos varía de acuerdo a las condiciones ambientales de cada lugar, y representa información importante para su conservación. Se estudió el ciclo reproductivo de la almeja Megapitaria squalida utilizando cortes histológicos de la gónada y cambios en el número y tamaño de los oocitos, en el sur del Golfo de California (Bahía Altata, Sinaloa, México), desde junio 2013 a junio 2014. El análisis histológico de las gónadas, mostró eventos de desove todo el año con dos picos: el primero fue registrado en octubre acompañado con un fuerte decremento en peso de los animales; el segundo en febrero caracterizado por un alto porcentaje de desove en la población. Se observó un periodo de reposo en diciembre. La proporción sexual (hembras:machos) de la población de almejas fue 1.08:1 (χ2 = 5.72, g.l. = 1, P < 0.05). El número y tamaño promedio de los oocitos mostró diferencias (P < 0.05) entre los muestreos mensuales, y fluctuaron de 34.6 ± 5.8 µm en junio 2014 a 41.9 ± 6.8 µm en febrero 2014, y de 443.8 ± 424.5 en febrero 2014, a 1 214.4 ± 267.6 en abril 2014. Se propone una temporada de veda desde octubre a noviembre, ya que en estos meses la liberación de gametos por la población fue más intensa.

Reproduction of Blackfin tuna Thunnus atlanticus (Perciformes: Scombridae) in Saint Peter and Saint Paul Archipelago, Equatorial Atlantic, Brazil / Reproducción del atún de aleta negra Thunnus atlanticus (Perciformes: Scombridae) en el Archipiélago San Pedro y San Pablo, Atlántico Ecuatorial, Brasil

The reproduction of Blackfin tuna Thunnus atlanticus has been described for coastal regions, and for a long time, this species was considered to be a strictly continental spawner. Recently, this species was observed around a seamount habitat 500 nautical miles Northeast of Brazil, located between South America and Africa. In this study we describe the reproductive biology of Blackfin tuna at Saint Peter and Saint Paul Archipelago (SPSPA). Male and female gonads were sampled from December 2008 to July 2010, and analyzed macro and microscopically. A total of 361 fish were sampled (247 males and 114 females). Males were more common than females, with a sex ratio of 2.2 ♂:1♀. The fork length (FL) of all sampled specimens ranged from 38 to 98cm, and larger length classes were more frequent in males. It was possible to distinguish six maturity phases for females: immature, developing, spawning capable, actively spawning, regressing and recovering. Five phases were identified for males: immature, developing, spawning capable, actively spawning and recovering. The gonad index (GI) mean monthly values ranged from 6.6 (SD=4.1) to 58.4 (SD=34.7) for females, and from 2.6 (SD=1.3) to 66.2 (SD=30.4) for males. For both sexes, the largest GI values were observed at the beginning of the first semester of the year. Size at first maturity was estimated at 48cm FL and 55cm FL for females and males respectively. Approximately 80% of the specimens were adults and considered to be in reproductive conditions. Histological analysis of the ovaries and testes showed that most of the specimens were sexually mature and were reproductively active during all months of the year. However, females with mature ovaries, with large amounts of hydrated oocytes and post-ovulatory follicles, were mainly found from December to March, thus these months may constitute the main spawning season in SPSPA. Batch fecundity varied between 272 025 and 1 140 584 oocytes for 56 and 68cm FL females respectively. Oocyte development and spawning patterns suggest a multiple spawning behavior. The results revealed that Blackfin tuna is using the SPSPA as a spawning ground, similar to other species commonly observed in the same area during the same reproductive season.

A pesar de la importancia de las capturas del atún de aleta negra Thunnus atlanticus en el noreste de Brasil y en las cercanías del Archipiélago San Pedro y San Pablo (ASPSP), hay una escasez de información sobre su reproducción, especialmente en las islas. La reproducción del atún de aleta negra en este archipiélago se estudió de diciembre 2008 a julio 2010. Con este fin, se recolectaron 361 gónadas de hembras y machos, los machos fueron predominantemente más frecuentes en la muestra total, con una proporción sexual de 1♀:2.2 ♂. La longitud furcal todos los ejemplares muestreados varió entre 38 y 98 cm, y los machos fueron más abundantes en las clases de mayor longitud. Los valores medios mensuales del índice gonadal (IG) variaron de 6.6 (SD=4.1) a 58.4 (SD=34.7) y de 2.6 (SD=1.3) a 66.2 (SD=30.4) para hembras y machos, respectivamente. Los mayores valores de IG para ambos sexos fueron observados el inicio del primer semestre. Los análisis histológicos mostraron que la mayoría de los ovarios y testículos correspondieron a especímenes aptos para reproducirse. Sin embargo, hembras con ovarios maduros, con gran cantidad de oócitos hidratados y folículos post ovulatorios, se encontraron principalmente de diciembre a marzo, que se considera es la época de reproducción del atún de aleta negra alrededor del ASPSP.

Dynamics of ovarian maturation during the reproductive cycle of Metynnis maculatus, a reservoir invasive fish species (Teleostei: Characiformes)

In this study, we evaluated the dynamics of ovarian maturation and the spawning processes during the reproductive cycle of Metynnis maculatus. Adult females (n = 36) were collected bimonthly between April 2010 and March 2011. The mean gonadosomatic index (GSI) was determined, ovarian and blood samples were submitted for morphometric evaluation and the steroid plasma concentration was determined by ELISA. This species demonstrated asynchronous ovarian development with multiple spawns. This study revealed that, although defined as a multiple spawning species, the ovaries of M. maculatus have a pattern of development with a predominance of vitellogenesis between April and August and have an intensification in spawning in September; in October, a drop in the mean GSI values occurred, and the highest frequencies of post-ovulatory follicles (POFs) were observed. We observed a positive correlation between the POF and the levels of 17α-hydroxyprogesterone. Metynnis maculatus has the potential to be used as a source of pituitary tissue for the preparation of crude extracts for hormonal induction; the theoretical period for use is from September to December, but specific studies to determine the feasibility of this approach must be conducted.

Neste estudo, avaliamos a dinâmica da maturação ovariana a desova durante o ciclo reprodutivo de Metynnis maculatus. Fêmeas adultas (n = 36) foram coletadas bimestralmente entre abril de 2010 e março de 2011. O índice gonadossomático (IGS) foi calculado e amostras de ovário e de sangue foram submetidas à avaliação morfométrica e das concentrações plasmáticas dos esteroides por ELISA, respectivamente. A espécie apresenta desenvolvimento ovariano assincrônico, com múltiplas desovas. Neste estudo revelamos que mesmo sendo de desova parcelada, os ovários do M. maculatus mostraram um padrão de desenvolvimento com predomínio de atividade vitelogênica entre abril a agosto e intensificação da desova em setembro. Em outubro houve uma diminuição nos valores médios de IGS, bem como registramos as maiores frequências de folículos pós-ovulatórios (FPOs). Observamos uma correlação positiva entre a frequência de FPOs e a concentração plasmática de 17 α-OHP. O M. maculatus tem potencial para ser usado como fonte para uso de hipófise para preparo de extrato bruto para indução hormonal, sendo o período teórico para coleta de hipófises de setembro a outubro, mas estudos específicos para esta finalidade ainda precisam ser desenvolvidos.

Reprodução da piranha-amarela Serrasalmus spilopleura Kner, 1858, em lagos de várzea, Amazonas, Brasil / Reproduction of piranha Serrasalmus spilopleura Kner, 1858, on the floodplain lakes, Amazon, Brazil

Serrasalmus spilopleura (piranha-amarela) é fonte de proteína animal para as populações ribeirinhas, sendo ocasionalmente comercializada nos mercados e feiras da região. Considerando a escassez de informações sobre a reprodução de peixes em lagos de várzea, o trabalho propõe investigar o comprimento médio de primeira maturação sexual e a época de desova de S. spilopleura nos lagos Jaitêua-São Lourenço, Manacapuru, AM. Também são relacionados os fatores abióticos (nível de água e profundidade) e bióticos (fator de condição) com a época de desova. Foram capturadas 232 fêmeas no período de agosto de 2006 a junho 2007, utilizando rede-de-emalhar e, em laboratório, foram realizadas as biometrias e identificação dos estádios de maturação gonadal. A época de desova das fêmeas foi estabelecida através da distribuição temporal da freqüência relativa nos diferentes estádios de maturação gonadal e do fator de condição relativo, Kn = Pt/aCp b, onde: Kn = fator de condição relativo; Pt = peso total; Cp = comprimento padrão e, a e b = constantes obtidas da regressão entre peso e comprimento. E, para verificar se há correlação entre o fator de condição e época de desova com a profundidade dos lagos, utilizou-se o coeficiente de correlação de Spearman ao nível de significância 5 por cento. A amplitude do comprimento padrão dos exemplares variou de 7 a 22 cm. A análise de correlação entre o Kn e a época de desova foi positiva (r s = 0,58, p < 0,05), ou seja, a época de desova correspondeu ao período de maior Kn, sugerindo ser um indicador para época de desova de S. spilopleura. Houve correlação negativa entre a profundidade e o Kn (r s = -0,66, p < 0,05) e entre a profundidade e a época de desova (r s = -0,25, p < 0,05). O L50 estimado correspondeu a 13,0 cm ± 0,09 e o L100 a 17,0 cm ± 0,02. S. spilopleura desenvolve o seu ciclo reprodutivo no complexo lacustre lago Grande de Manacapuru, e com base nos indicadores reprodutivos, época de desova e fator de condição relativo, a desova começa em dezembro, logo no início da enchente, se estendendo até fevereiro, meados de enchente, coincidindo com a elevação do nível da água do rio Solimões-Amazonas e da profundidade nos lagos.

Serrasalmus spilopleura (piranha) is a source of animal protein for marginal populations, it is occasionally sold in markets and fairs in the region. Considering the scarcity of information on reproduction of fish in floodplain lakes, the study proposes to investigate the average size at first maturity and spawning season of S. spilopleura lakes Jaitêua-São Lourenço, Manacapuru, AM. Also related are the abiotic factors (water level and depth) and biotic (condition factor) with the spawning season. 232 females were captured from August 2006 to June 2007, using gill net, and in the laboratory were used for biometrics and identification of the maturation stages. The spawning season of the females was established through the temporal distribution of relative frequency in different maturation stages and relative condition factor, Kn = Pt/aCp b, where: Kn = relative condition factor; Pt = total weight; Cp = standard length, a and b = constants obtained from regression between weight and length. And, to check for correlation between condition factor and with the spawning season depth of the lakes, we used the Spearman correlation coefficient of the 5 percent significance level. The amplitude of the standard length of specimens ranged 7-22 cm. Correlation analysis between Kn and spawning season (r s= 0.58, p < 0.05) was positive, i.e. the spawning season corresponded to the higher Kn, suggesting that an indicator of spawning season of S. spilopleura. There was a negative correlation between the depth and Kn (r s = -0.66, p < 0.05) and between depth and spawning season (r s = -0.25, p < 0.05). The estimated L50 corresponded to 13.0 ± 0.09 cm and 17.0 ± 0.02 cm L100, S. spilopleura develops its complex reproductive cycle in the lake of Grand Lake Manacapuru, and based on indicators of reproduction, spawning season and relative condition factor, spawning begins in December, early on the rising extending to February, mid-rising, which coincided with the rise of water level of the Solimões-Amazon River and deep lakes.

BIOLOGÍA REPRODUCTIVA DEL LISO Rhamdia quelen (PISCES: HEPTAPTERIDAE) EN EL RÍO SINÚ, COLOMBIA / Reproductive Biology of Liso Rhamdia quelen (Pisces: Heptapteridae) in the Sinu River, Colombia

RESUMEN Se estudió la biología reproductiva del Liso (Rhamdia quelen) en el río Sinú. Los peces fueron colectados entre enero y diciembre del 2005, con tallas y pesos entre 15,5 -37 cm de longitud total (LT) y 28 -486 g de peso total. Las gónadas se conservaron en solución Gilson, se utilizó la escala de Vazzoler y se estimó proporción sexual, índices de madurez sexual, época de desove, talla media de madurez sexual, diámetro de ovocitos y fecundidad. Se evaluaron 207 hembras, 130 machos y un indiferenciado, con proporción sexual hembra: macho de 1,6:1, diferente a lo esperado. La talla media de madurez fue estimada en 24 cm LT para sexos combinados, el diámetro promedio de los ovocitos fue de 963 µm y la fecundidad promedio fue estimada en 26.305 ovocitos, con ecuación de mejor ajuste F=2960,61 WG 0,88, r=0,94, n=125. El Liso es un pez con tipo de desarrollo ovocitario asincrónico en más de dos grupos, con desoves parciales durante todo el año.

ABSTRACT The reproductive biology of Liso (Rhamdia quelen) in the Sinu river was studied. The fishes were collected between January and December 2005, with lengths ranging 15,5 -37 cm of total length (TL) and 28 - 486 g of total weight. The gonads were placed in Gilson solution, the Vazzoler scale was applicated and sexual proportion, sexual maturity index, spawning season, the length at first maturity, ovocites’s diameter and fecundity were estimated; 207 females, 130 males and 1 undifferentiated were evaluated, with sexual proportion female: male of 1,6:1, different from expected. The length at first maturity was estimated in 24 cm TL for combined sexes; average ovocites’s diameter was 963 mm and average fecundity was estimated in 26.305 ovocites, with better equation F=2960,61 0,88, r=0,94, n=125. The Liso is a fish with asynchronous oocyte development in more than two groups, with partial spawning throughout the year.

Reproduction of the fish Lutjanus analis (mutton snapper; Perciformes: Lutjanidae) from Northeastern Brazil

The mutton snapper Lutjanus analis is an overexploited species of economic importance for the Northeast region of Brazil. To determine the reproductive aspects of the mutton snapper, biological data were sampled from Bahia, Pernambuco, Paraíba, Rio Grande do Norte and Ceará States, between 7 and 200m depth, from February 1997 to December 1999, performed in the Brazilian Economic Exclusive Zone Study Program (REVIZEE-NE Program). Data on total length (TL), fork length (FL), standard length (SL), total weight (TW) and gutted weight (GW) were measured. The gonads were collected and fixed in FAACC for histological analysis on maturational stage and calculation of the gonadosomatic index (GSI). A total of 135 fishes were collected; from these, 74 were females and 61 were males. Females were between 28.0 and 69.0cm (TL) and the males between 35.0 and 75.0cm (TL). Mutton snapper are gonochorists, and the spawning season, determined by the maturity stages frequency and the GSI, occurred between November and April, with peak spawning in March. The mature females’ minimum length was 28.0cm fork length, smaller than the minimum maturation length previously reported for the species in Cuba. The exploitation status of the species and the biological traits enhances the importance of establishing spatial and seasonal protection measures such as protected areas both in nursery and spawning sites. Rev. Biol. Trop. 58 (3): 791-800. Epub 2010 September 01.

El pargo criollo Lutjanus analis es una especie de importancia económica para la región noreste de Brasil, que esta siendo sobreexplotada. Para determinar sus aspectos reproductivos, se tomaron datos biológicos en los Estados de Bahía, Pernambuco, Paraíba, Rio Grande do Norte y Ceará, entre 7 y 200m de profundidad, de febrero 1997 a diciembre 1999, en el Programa de REVIZEE-NE en la Zona Económica Exclusiva de Brasil. Se midieron la longitud total (LT), longitud de horquilla (FL), longitud estándar (SL), el peso total (TW) y peso evicerado (GW). Las gónadas se recolectaron y fijaron en FAACC para el análisis histológico de las etapas de maduración y el cálculo del índice gonadosomático (IGS). Se recolectaron un total de 135 hembras y 61 machos. Las hembras midieron 28.0-69.0cm (TL) y los machos entre 35.0-75.0cm (TL). Lutjanus analis es gonocorista, y la época de desove, determinada por la frecuencia de las etapas de maduración y el GSI, ocurre entre noviembre y abril, con con un pico de desove en marzo. La longitud mínima (FL) de las hembras maduras fue 28.0cm, menor que la reportada para la especie en Cuba. El estado de explotación de las especies y los indicadores biológicos observados justifican el establecimiento de medidas de protección espacial y temporal, como las áreas protegidas, tanto en sitios de crianza como en zonas de desove.