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Abstract. Reproductive parameters of the females of Penaeus semisulcatus regarding the process of ovary maturation, the degree of synchronization of the ova maturation stage within an ovary, the correlation between female length and both maturity and fecundity, as well as the relationship between moulting, copulation and ovarian maturity stage were investigated.
The seasonal and spatial pattern of the reproduction of the female population of P. semisulcatus along the southeastern coast of the Mediterranean was determined.
Average ova diameter, morphological appearance of the ova, presence of sperm, characteristics of the spermatophore, and hardness of the cuticle were used in order to study the above parameters. 相似文献
The seasonal and spatial pattern of the reproduction of the female population of P. semisulcatus along the southeastern coast of the Mediterranean was determined.
Average ova diameter, morphological appearance of the ova, presence of sperm, characteristics of the spermatophore, and hardness of the cuticle were used in order to study the above parameters. 相似文献
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采用RT-PER原理和长片段扩增技术克隆短沟对虾和斑节对虾酚氧化酶原基因。设计合成特异引物、提取血细胞总RNA,反转录后扩增获得的特异片段回收并克隆到pGEM-TEasyVector系统的T载体上,重组子进行碱基序列测定。结果表明,所克隆的短沟对虾酚氧化酶原基因含起始密码子A1B到终止密码子TGA的2055bp,编码684个氨基酸。斑节对虾酚氧化酶原基因含ATG到TGA的2061bp,编码686个氨基酸。短沟对虾酚氧化酶原推算分子量为78153Da,等电点pI为6.25;斑节对虾则为78581Da,pI为5.83,用DNA分析软件分析显示两种对虾酚氧化酶原基因具有高度的同源性,二者的碱基和推测的氨基酸序列同源性分别为93%和92%;对虾与其他节肢动物酚氧化酶原基因的同源性的高低与种类间亲缘关系相关;不同种类间酚氧化酶活性中心重要组成部分的2个铜结合位点、位于铜结合位点内的6个组氨酸以及与铜结合位点相邻的氨基酸序列高度保守。 相似文献
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The role of life‐history traits,selective pressure and hydrographic boundaries in shaping the genetic structure of the transparent goby,Aphia minuta
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Paolo Ruggeri Andrea Splendiani Massimo Giovannotti Tatiana Fioravanti Giulia Occhipinti Paola Nisi Cerioni Vincenzo Caputo Barucchi 《Marine Ecology》2016,37(3):518-531
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年龄和生长速度等参数是渔业资源评估和管理的基础。鸢乌贼生命周期短、生长速度快。为研究鸢乌贼的日龄和生长, 利用2016年10月—2017年9月灯光罩网作业方式采集的南海鸢乌贼样本, 通过耳石微结构研究南海鸢乌贼不同种群、性别间的日龄组成和生长的差异, 结果表明: 1) 鸢乌贼中型群日龄范围48~125d, 优势日龄61~80d, 雌雄个体日龄组成差异显著; 微型群日龄范围44~95d, 优势日龄51~70d, 雌雄个体日龄组成差异极显著。2) 鸢乌贼中型群孵化时间为2016年7月—2017年7月, 1月和7—8月为孵化高峰期; 微型群孵化时间为2016年6—10月和12月至翌年2月, 1月和8月为孵化高峰期。3) 中型群雌雄胴长、体质量与日龄分别符合对数和线性关系; 微型群雌雄胴长与日龄分别符合对数和Logistic关系, 而体质量与日龄符合Logistic关系。4) 南海鸢乌贼微型群生长速度大于中型群, 微型群雄性个体生长速度大于雌性, 而中型群雄性个体生长速度小于雌性。通过对耳石生长纹的分析, 了解鸢乌贼的日龄组成、推算孵化时间、选出合适的生长方程及估算生长速度, 为渔业生物学提供基础资料。 相似文献
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Xindong Pan Zhenjiang Ye Binduo Xu Tao Jiang Jian Yang Jiahua Cheng Yongjun Tian 《海洋学报(英文版)》2020,39(12):54-64
Japanese Spanish mackerel, Scomberomorus niphonius, is a commercially important, highly migratory species that is widely distributed throughout the northwestern Pacific region. However, its life history and migratory patterns are only partially understood. This study used otolith chemistry to investigate the migratory pattern of S. niphonius in the southern Yellow Sea, an important fishing ground. Transverse sections of otoliths from 15 age-1 spawning or spent individuals, comprising up to one complete migration cycle, were analyzed from the core to the margin by using laser ablation inductively coupled plasma mass spectrometry. The ratios of the element to Ca were integrated with microstructural analysis to produce age-related elemental profiles. Combining multi-elemental analysis of otolith composition with multivariate analytical models, we quantified structural changes in otolith chemistry profiles. Results revealed there were diverse changing patterns of otolith chemistry profiles for detected elements and the elements of Na, Mg, Sr and Ba were important for the chronological signal. Five clusters were identified through chronological clustering, representing the five life stages from the early stage to the spawning stage. Variation of Ba:Ca ratio was most informative, showing a step-decreasing pattern in the first four stages and a rebound in the spawning stage. These results support the hypothesized migratory pattern of S. niphonius: hatching and spending their early life in the coastal sandy ridges system of the southern Yellow Sea, migrating northeastward and offshore for feeding during juvenile stage, aggregating in early October and migrating outward to the Jeju Island for wintering, and returning to the coastal waters for spawning. This study demonstrated the value of life-history related otolith chemistry profiles combined with multivariate analytical models was a means to verify the migration patterns of S. niphonius at regional scales with potential application in fisheries assessment and management. 相似文献
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Recruitment of early life stages into estuaries is an integral part of the life cycle of many marine fish species. Although estuaries are naturally environmentally dynamic, they also are subject to anthropogenic disturbances, including land use and climate change, which may affect recruitment. Rhabdosargus holubi is an endemic marine-spawning species predominantly associated with freshwater-rich estuaries which serve as nursery areas for postflexion larvae and juveniles. This study assessed the effect of environmental variables on the dynamics of recruitment of R. holubi larvae and juveniles into the Swartkops and Sundays estuaries, South Africa. Over a period of two years, fyke nets were set at each estuary mouth to monitor movement into the estuaries at each tidal phase over a 24 h cycle during two sampling sessions per season. Rhabdosargus holubi larvae recruited into estuaries primarily in summer and autumn and during the ebb tide at night, while juvenile movements showed no pattern. Salinity, turbidity and temperature were significantly important factors affecting R. holubi recruitment, with pH having no significant effect. Turbidity and salinity are affected by rainfall and freshwater abstraction which may thus influence recruitment. Rhabdosargus holubi is dependent on estuaries, so a combination of future changes in turbidity, salinity and temperature due to predicted climate change may place populations at risk. 相似文献
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A Lagrangian ensemble model describing the population dynamics of Neocalanus cristatus was developed. To describe the ecology of N. cristatus, life stage must be included in the model. For this purpose, a new zooplankton compartment, divided into nine life stages, was added to the North Pacific ecosystem model for understanding regional oceanography. In addition, we introduced Lagrangian particles for the copepod population. Each Lagrangian particle represented a population of the same cohort of copepods with information on representative age, developmental stage, growth rate, structural weight, and food satiation. The new model revealed that surviving cohorts are only matched with the phytoplankton bloom after the nauplii stages. The model showed that the existing phytoplankton concentration when copepodites of N. cristatus appear in the surface water determines the development pattern of copepodite stages. The timing of the seasonal phytoplankton bloom depends on climate change, and a sensitivity analysis showed that the multiple spawning strategy through time has an important role in matching the unstable seasonal bloom cycle on a daily basis. The model including the cohorts can collaborate closely with weekly or monthly observations to reveal the rapid response of the marine ecosystem. 相似文献
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Angelina Metaxatos 《Journal of Sea Research》2004,52(4):189
The venerid bivalve Callista chione is the most prominent suspension-feeding bivalve inhabiting the soft bottom of coastal areas in the northern Euboikos Gulf (Aegean Sea), where it is exploited by small-scale fishery. The parameters of the von Bertalanffy growth function were estimated and the somatic production-to-biomass ratio was found to be 0.45 y−1. The maximum age of adult individuals was 17 years. The species is gonochoristic, its oocyte diameter ranged from 54.5 to 120 μm with a conspicuous jelly-coat. Microscopical examination of the gonads showed that gonadal production did not start until the second year of life. The observations on the gonadal cycle indicate that this bivalve is capable of year-round reproduction. 相似文献
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Katsumasa Yamada Masakazu Hori Yoshiyuki Tanaka Natsuki Hasegawa Masahiro Nakaoka 《Estuarine, Coastal and Shelf Science》2010
We examined the variation in habitat use and diet of three dominant fish species (Myoxocephalus brandti, Pholidapus dybowskii, and Pholis crassispina) in a seagrass meadow in the Akkeshi-ko estuary in northeastern Japan, where broad and dense Zostera marina beds exist, using a semi-quantitative census of the fishes and analyses of their stomach contents. Differences among the three fish species in the temporal variation in abundance of each age class (mainly 1- and 2-year age classes) indicated that the temporal pattern of utilization of the seagrass meadow were different among them. In the semi-quantitative dietary analysis, two prey categories, i.e., taxonomic group (order and suborder) and functional group, were used to explain the variation in prey composition with size-dependent changes. The six prey functional groups were classified based on the ecological traits of the prey, i.e., trophic level, size, and life type (habitat and behavior). Ontogenetic shifts in prey of the three fish species could be fully explained by a combination of the two prey categories, and not by the use of only one category (taxonomic or functional group). The pattern of ontogenetic shifts in prey differed among the fish species and size (age) classes. These results indicate that segregation of habitat (seagrass meadow) and prey group (taxonomic and functional group) is performed among the three species, which may contribute to their coexistence in this estuary. 相似文献
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Charles B. Miller Bruce W. Frost Harold P. Batchelder Martha J. Clemons Richard E. Conway 《Progress in Oceanography》1984,13(2):201-243
Life histories for the dominant, larger copepods of the subartic Pacific have been constructed by sampling from weatherships patrolling Ocean Station P (50°N, 145°W) during 1980 and 1981. Neocalanus plumchrus reproduced at depths below 250 m from July through February. Copepodite stages were present in surface layers from October through August with a large peak in numbers and biomass in spring. Fifth copepodites prepared for diapuse in 38 days during spring and descended to depths below 250 m. They commenced immediately to mature, and the females reproduced without renewed feeding. This schedule contrasts with that of the population in the Strait of Georgia, which remains in diapause from July to January and matures exclusively in January and February. There appears to be a difference between the coastal and oceanic habitats in preparing the diapausing individuals for maturation.Maturation of the diapausing stock of N. plumchrus maintained constant adult populations, averaging 714 males m?2 from June through October and 1,434 females m?2 from August through January. This constancy, together with the exponential pattern of decline in the diapause stock from September through February, suggests that density of adults may regulate maturation of fifth copepodites. Offspring of individuals delaying maturation and, thus, reproduction would benefit from the resulting moderation of intraspecific competition, probably that among copepodites.Reproduction of Neocalanus cristatus also occurred below 250 m, and, while spawning was continuous through the year, there was a substantial peak in November. That resulted in a peak of abundance for early copepodite stages in mid-winter, and a peak for the fifth copepodite stage in June. Stocking of the population of fifth copepodites in diapause below 250 m occurred from July through October. Some fifth copepodites were present in surface layers through the entire summer, and some younger copepodites persisted through the summer in progressively declining abundance just below the mixed layer. In autumn 1980 resurgence of early copepodite populations was rapid, occurring during the course of a prolonged October storm. The storm may have improved the habitat either by cooling the mixed layer or by resupplying nutrients to the euphotic zone.Eucalanus bungii reproduced in the mixed layer in early May and in early July. The first event was a spawning by females that had previously spawned in 1979 and then had returned to diapause. The second, heavier spawning (more females, more eggs per female) was by newly matured females from stocks that had overwintered as fifth copepodites. Nauplii peaked sharply in abundance on 19 July, one week after the peak in spawning. First and second copepodites peaked on 1 August, and all had advanced to the third copepodite stage by September. The diapause stock was established by September, principally between 250 and 500 m, and consisted of copepodite stages from third to sixth. Duration of the E. bungii life cycle appears to be typically two years. New nauplii develop as far as the third or fourth copepodite stage during their first summer, then enter diapause. The second summer they advance to the fifth copepodite stage and reenter diapause. Fifth copepodites mature in their third summer at two years of age. The males remain at depth and mate without subsequent feeding. Females migrate at night to the mixed layer where spawning occurs. About 20% of females that had already spawned in 1980 reentered diapause. They would reproduce again in their fourth summer at three years of age. All aspects of the life cycle suggest low mortality rates for copepodite stages, particularly at depth in the habitat occupied during diapuse. There can be no premium on rapid reproduction for E. bungii in the subartic Pacific, and there must even be benefit from spreading reproduction between years. This iteroparity may amount to a “bet-hedging” tactic, the young from a given mother having more than one chance to find sustaining conditions. It also produces gene flow between the year classes of the biennial life cycle. 相似文献
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Anna Badosa Dani Boix Sandra Brucet Rocío Lpez-Flores Xavier D. Quintana 《Estuarine, Coastal and Shelf Science》2006,66(3-4):513-522
The role of the hydrological regime in the nutrients and zooplankton composition and dynamics has been analysed in five lagoons of La Pletera salt marshes (NE Iberian Peninsula) during a complete hydrological cycle (2002–2003). Two of the lagoons have their origin in the old river mouths while the other three were recently created in the framework of a Life Restoration project. This fact has also allowed us to study the effect of the lagoon age on nutrient and zooplankton composition and dynamics. The salt marsh hydrology is determined by a prolonged period of confinement without water inputs, irregularly interrupted by sudden water inputs due to flooding events (sea storms or intense rainfalls). While the dynamics of oxidized nitrogen compounds in the lagoons depends on the water inputs variability within each hydrological cycle, the internal load of phosphorus, total nitrogen and organic matter is related more to the cumulative mechanisms during the confinement periods. Accumulation processes may be easily related to lagoon age, since old lagoons have higher content of nutrients and organic matter, suggesting that these lagoons progressively accumulate nutrients during the successive confinement events. This is the usual case for most Mediterranean salt marshes without an artificially manipulated water regime. The zooplankton community in La Pletera integrates the effects of both the hydrological regime and the lagoon age since the former determines the temporal pattern of the main zooplankton species and the latter explains differences in composition and structure between old and new lagoons. 相似文献
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Rodrigo L. Moura Ronaldo B. Francini-Filho Eduardo M. Chaves Carolina V. Minte-Vera Kenyon C. Lindeman 《Estuarine, Coastal and Shelf Science》2011
The early life history of Western Atlantic snappers from the Southern hemisphere is largely unknown. Habitat use of different life stages (i.e. size categories) of the dog snapper (Lutjanus jocu) was examined across the largest South Atlantic reef–estuarine complex (Abrolhos Shelf, Brazil, 16–19° S). Visual surveys were conducted in different habitats across the shelf (estuary, inner-shelf reefs and mid-shelf reefs). Lutjanus jocu showed higher densities on inner-shelf habitats, with a clear increase in fish size across the shelf. Individuals <7 cm were associated with both the estuary (mangrove and rocky habitats) and inner-shelf reefs (particularly shallow fore-reefs and tide pools). Individuals ranging 10–30 cm were broadly distributed, but consistently more abundant on inner-shelf reefs. Individuals between 30 and 40 cm were more common on mid-shelf reefs, while individuals >40 cm were recorded only on mid-shelf reefs. Literature data indicate that individuals ranging 70–80 cm are common on deep offshore reefs. This pattern suggests that the dog snapper performs ontogenetic cross-shelf migrations. Protecting portions of the different habitats used by the dog snapper during its post-settlement life cycle is highlighted as an important conservation and management measure. 相似文献
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《African Journal of Marine Science》2013,35(4):343-353
A previous study that explored the age and growth of red steenbras Petrus rupestris (Valenciennes, 1830), a large sparid (family Sparidae, seabreams or porgies) endemic to South Africa and reported to approach 2 m in length, provided estimates as a moderately slow-growing species with a maximum age near 30 years. The stock is considered collapsed and a fishing moratorium was imposed in 2012, resulting in this species being assessed as Endangered by the IUCN. One consideration in addressing population status is validation of life-history traits. In this study, estimates of age for red steenbras from thin-sectioned otoliths were reassessed visually in terms of both the original ages and revised estimates using a different age-reading pattern. The revised ages exceeded the original ages by up to 30 years, with a maximum estimated age of 55 years from a well-defined otolith section that provided a basis for the revised age-reading procedure. Bomb radiocarbon (14C) dating revealed there was an offset in the timing of the 14C rise on the Agulhas Bank that, when coupled with considerations for regional oceanography, provided support for the revised age-reading pattern and an estimated longevity that exceeds 50 years. These findings were further supported by the fortuitous recapture of a tagged red steenbras that was at liberty for 22 years. 相似文献
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To examine the accumulation pattern of organotin compounds (OTs) in relation to the migration of diadromous fish, tributyltin (TBT) and triphenyltin (TPT) compounds and their derivatives were determined in the muscle tissue of both sea-run (anadromous) and freshwater-resident (nonanadromous) types of the white-spotted charr Salvelinus leucomaenis. There were generally no significant correlations between the TBT and TPT accumulation and various biological characteristics such as the total length (TL), body weight (BW), age and sex in S. leucomaenis. It is noteworthy that the TBT and TPT concentrations in sea-run white-spotted charr were significantly higher than in freshwater-resident individuals, although they are intraspecies. These results suggest that the sea-run S. leucomaenis has a higher ecological risk of TBT and TPT exposure than the freshwater-residents during their life history. 相似文献
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Abstract. In the Oslofjord two species of the amphipod genus Chaetogammarus, C. marinus (LEACH, 1815) and C. stoerensis (REID, 1938) were found to be annual species with similar life cycles. No differences in life cycle traits were found between two C. stoerensis populations where one occupied a freshwater influenced beach and the other a fully marine beach. The breeding period of both species was short and lasted from April to the end of May or early June. Frost prohibited embryonic development in the first part of April so few juveniles were released before the middle of May. In late May and early June all specimens which survived the winter died. The sex ratio was skewed in favour of females, and females produce two to three broods during lifetime. Between 16 and 31 % of the newly laid eggs failed to complete their development. The life cycle of populations of the two species from other geographical areas are compared with the Oslofjord data. 相似文献