Batch Spawning Research Articles

Using mariculture as a breeding site: reproduction of <em><em>Hypleurochilus fissicornis</em></em> (Actinopterygii: Blenniidae)

Mariculture in estuaries provides substrate for colonization by fouling organisms, thus attracting small cryptic fish species hitherto unknown in this environment. The blenny Hypleurochilus fissicornis is one of the species that is associated with this new system and is found in high abundance in bivalve farming. To understand the reproductive strategy that this species uses in this new environment, we collected specimens monthly in a mariculture on the southern coast of Parana State (Brazil). After obtaining morphometric data, we removed gonads to determine sex and maturity stage. Gonads were weighed and analysed histologically. Oogenesis showed the same pattern as in other teleosts, but spermatogenesis showed a very complex dynamics. The spawning is multiple and synchronous between sexes, lasting eight months (May to December) and peaking in winter. Hypleurochilus fissicornis was reproductively successful using the mariculture as a breeding site. The species has a variety of tactics to protect its offspring (e.g. batch spawning, long reproductive period, reduced L50, parental care and a reproductive peak in winter).

Life history traits and implications for conservation of rock carp Procypris rabaudi Tchang, an endemic fish in the upper Yangtze River, China

Rock carp is an endemic fish in the upper Yangtze River basin. Its populations have dramatically declined in the recent years due to human activities, such as overfishing and damming. In the present study, with the aim to give suggestions for better conservation, we investigated age, growth, and reproductive biology of the rock carp using samples collected between 2007 and 2013 from the Chishui River. The results indicate that there are no significant differences between the length–weight relationships of females and males (W = 0.015SL3.155). The von Bertalanffy growth curves computed by the observed length-at-age data could be expressed as Lt = 64.9(1 − e−0.101(t+0.217)). The estimated length at 50 % sexual maturity for males is 24.2 cm (approximately aged 4) and 37.0 cm for females. Female gonad analysis suggests that rock carp is a batch spawner, which can spawn at least twice during the reproductive season, from April to August. Standard length and age of 86.5 % individuals were below 25 cm and 4 years, respectively, indicating that the exploitation is too intensive and that populations are undergoing miniaturization. These data corroborate that a combination of natural and anthropogenic factors has caused a sharp decline in wild populations during recent years, calling for immediate design and implementation of conservation measures for this species.

Health and reproduction of red mullet, Mullus barbatus, in the western Mediterranean Sea

The reproductive and general health of exploited fish stocks is an essential element of sustainable and profitable fisheries. The main purpose of this study was to assess the relationships between reproduction and two important parameters of fish health (parasitism and energy reserves) in female specimens of red mullet, Mullus barbatus, from the western Mediterranean Sea. We present new data for this species on (i) the prevalence and intensity of infection by metazoan parasites; (ii) the total lipid content in muscle and gonads as a measure of condition and (iii) fecundity and egg quality as a measure of their reproductive capacity. The results show that M. barbatus is a batch spawner with an income breeding strategy, an asynchronous development of oocytes and indeterminate fecundity. The results also indicate that the three most abundant and prevalent parasites significantly affect the condition and reproduction of M. barbatus. Specifically, the digenean, Opecoeloides furcatus, causes a reduction in the female’s energy reserves, while the nematodes, Hysterothylacium fabri and H. aduncum, produce a rise in egg production but impair egg quality. These implications of the relationships between parasitism, fish health and fish reproduction should be taken into consideration in the assessment and management of exploited species.

Reproductive biology characteristics of red mullet (Mullus barbatusL., 1758) in Southern Adriatic Sea and management implications

The main important reproductive aspects of Mullus barbatus , one of the most important target species for the fishery in the Mediterranean basin, have been studied on the basis of MEDITS trawl survey and sampling of commercial landing. The total length (TL) of females has been demonstrated to be positively correlated with egg sizes and plasmatic concentration of vitellogenin. The possible implications of these aspects on the management of red mullet resources are discussed in this work. Moreover, the relationship between TL and fecundity follows an exponential pattern with a temporal trend during the spawning season. These results represent an important input for more effective management measures, such as the seasonal closure of fishery in summertime. The frequency distribution of the oocytes’ diameters showed an asynchronous ovarian organization with batch spawning pattern. Monthly variations in the gonadosomatic index and maturity stages percentage showed that males spawn during almost the entire year showed an increasing trend from November to June and a decreasing trend from July to October, while females in spawning phase are recorded from April to July, with peaks in May and June. The length at 50% maturity (L50) estimated respectively for females and males are 12.1 cm (±0.083) and 10.1 cm (±0.073).

Reproductive biology of largescale tonguesole Cynoglossus arel in coastal waters of Bandar Abbas, Persian Gulf, Iran

The objectives of this study were to determine the reproductive cycle of largescale tonguesole Cynoglossus arel, a commercially valuable flatfish species, in coastal waters of Bandar Abbas, along the south coast of Iran in the Persian Gulf. From October 2009 to September 2010, 905 fish were collected in monthly samples, and their length, weight, sex, gonad weight, and maturity status recorded. These data revealed that ovary weight in females is low from July to September, then increases to a peak in February followed by a decrease, indicating that the peak spawning season is from February to March with some spawning lasting until June. Males showed a corresponding seasonal pattern in testis weight, although with much less pronounced seasonal differences than gonad weight in females. Five maturity classes were described based on ovarian and testicular histology, corresponding with macroscopic analysis of gonads. The spawning season in C. arel is prolonged, similar to several other tropical flatfish species, and larger adult females tended to have an even more prolonged spawning period than smaller, presumably younger adult females. Combined, our results indicated that C. arel is a winter-to-spring batch spawner with an asynchronous type of ovarian development.

Understanding the determinate–indeterminate fecundity dichotomy in fish populations using a temperature dependent oocyte growth model

The fecundity type (determinate vs. indeterminate) is still uncertain for many commercially important fish populations affecting accuracy in fecundity estimations and hindering the selection of appropriate egg production methods for stock assessment purposes. It is broadly considered that boreal fish populations living in colder habitats are determinate spawners whilst populations residing in warmer habitats tend to be indeterminate spawners. In the present study we modelled the determinate–indeterminate fecundity type in batch spawning fishes, i.e. fish that spawn several batches of eggs per spawning season, based on the relationship between oocyte growth period and the duration of the spawning period considering that both variables can be affected by water temperature and latitudinal distributions. Individual based models (IBMs) were developed to explore how the interaction of these variables can result in a series of patterns along the continuum from extreme determinacy, i.e. annual fecundity being recruited long before the onset of the spawning period, to indeterminacy. Model simulations showed that fish stocks with oocyte growth periods longer than the spawning period are predicted to exhibit determinate fecundity which provides a fair justification for why cold water species with slow oocyte growth and limited spawning periods are determinate spawners and vice versa.

Sexually dimorphic transcription of estrogen receptors in cod gonads throughout a reproductive cycle

The role of sex steroid regulation in gonadal maturation is a very complex process that is far from being fully understood. Hence, we have investigated seasonal changes in gonadal expression of estrogen receptors (ERs) in Atlantic cod (Gadus morhua L.), a batch spawner, throughout the annual reproductive cycle. Three nuclear ER partial cDNA sequences (esr1, esr2a, and esr2b) were cloned and all esr transcripts were detected mainly in liver and gonads of fish of both sexes. In situ hybridization of esrs along with germ cell (vasa) and gonadal somatic cell markers (gonadal soma-derived factor (gsdf), 3β-hydroxysteroid dehydrogenase (3βhsd), and anti-Müllerian hormone (amh) for testicular, or gsdf for ovarian somatic cells) showed that all three esrs were preferentially localized within interstitial fibroblasts composed of immature and mature Leydig cells in testis, whereas they were differentially expressed in both follicular cells and oocytes in ovary. Quantitative real-time PCR analysis revealed a sexually dimorphic expression pattern of the three esr paralogs in testis and ovary. A significant increase in esr2a expression was identified in testis and of esr2b in ovary, whereas esr1 transcripts were elevated in both testis and ovary in February and March before the spawning period. The localization and sexually dimorphic expression of esr genes in gonads indicate a direct function of estrogen via ERs in gonadal somatic cell growth and differentiation for Leydig cell in testis and follicular cells in ovary throughout the annual reproductive cycle in Atlantic cod.

Reproductive ecology of the glacier lanternfish Benthosema glaciale

Myctophids play a key role in the transfer of energy in pelagic food webs, linking zooplankton to higher trophic levels. Data are presented, for the first time for the glacier lanternfish (Benthosema glaciale), on maturity ogives, size-at-maturity and reproductive strategy in terms of ovarian organization and fecundity type in two contrasting environments: North Atlantic and Mediterranean. We analysed 292 females collected in Flemish Cap during early summer 2009 and 2011 and off the Balearic Islands during late autumn 2009 and early summer 2010. The spawning season differed between areas. Size at 50% maturity in Flemish Cap was 47.6 and 49.1 mm in 2009 and 2011, respectively, but significantly smaller, 24.5 mm, in the Balearic sea. B. glaciale is a batch spawner with asynchronous ovarian development and indeterminate fecundity. Batch fecundity showed significant relationships with length and weight, although average relative batch fecundity was low (1031 ± 396 oocytes/gram). We compared two staining techniques: Hematoxylin–eosin and PAS–hematoxylin–metanil yellow with the latter being more useful to detect mature females and spawning indicators in regressing and regenerating females. Our results contribute to a better understanding of the reproductive potential and ecological role of this species, the most abundant myctophid in the northern Atlantic.

Reproductive biology of Bagrus docmak in the Victoria Nile, Uganda

Aspects of the reproductive biology of Bagrus docmak in the Victoria Nile were investigated between November 2005 and October 2006. Macroscopic and histological analysis of the gonads confirmed it as an asynchronous batch spawner which spawns throughout the year with bimodal spawning peaks coinciding with rainfall seasons. The first spawning peak occurred from March to May, the second from September to November. The sex ratio did not significantly deviate from 1:1. Length at sexual maturity was 33.6 cm and 31.6 cm fork length (FL) for females and males, respectively. Batch fecundity ranged from 1 000 eggs in 34 cm FL fish to 43 000 eggs in 79 cm FL fish, and correlated linearly with FL (r = 0.72) and body weight (r = 0.79). Mean relative batch fecundity was 6 eggs g−1 (SE 2). These results could guide research into the possibility of artificially inducing the fish to spawn, and its subsequent culture.

Batch spawning facilitates transfer of an essential nutrient from diet to eggs in a marine fish

Fatty acid composition of eggs affects development, growth and ecological performance of fish embryos and larvae, with potential consequences for recruitment success. Essential fatty acids in eggs derive from the maternal diet, and the time between ingestion and deposition in eggs is ecologically important but unknown. We examined the dynamics of diet-egg transfer of arachidonic acid (ARA) in the batch-spawning fish, red drum (Sciaenops ocellatus), by measuring ARA concentrations in eggs after a single diet shift and during a period of irregular variations in diet. ARA concentrations in eggs changed within 2-16 days of a diet shift. The rate of change was proportional to the magnitude of the shift, with no evidence of equilibration. These results are not consistent with eggs being assembled entirely from accumulated body stores. The immediate source of ARA in eggs appears to be the recent diet. We propose that batch spawning produces rapid diet-egg transfer of ARA because it removes large amounts of fatty acids from the body and prevents equilibration. The immediacy of the diet-egg connection suggests that spawning migration combined with short-interval batch spawning may have evolved to take advantage of nutrients critical for offspring survival that are available at the spawning site.

Ecology and population status of Trout-perch (Percopsis omiscomaycus) in western Lake Erie

Trout-perch Percopsis omiscomaycus is among the most abundant benthic species in Lake Erie, but comparatively little is known about its ecology. Although others have conducted extensive studies on trout-perch ecology, those efforts predated invasions of white perch Morone americana, Dreissena spp., Bythotrephes longimanus and round goby Neogobius melanostomus, suggesting the need to revisit past work. Trout-perch were sampled with bottom trawls at 56 sites during June and September 2010. We examined diets, fecundity, average annual mortality, sex ratio, and long-term population trends at sites sampled since 1961. Trout-perch abundance fluctuated periodically, with distinct shorter- (4-year) and longer-term (over period of 50years) fluctuations. Males had higher average annual mortality than females. Both sexes were equally abundant at age 0, but females outnumbered males 4:1 by age 2. Diets of trout-perch were dominated by macroinvertebrates, particularly chironomids and Hexagenia sp. Size distributions of trout-perch eggs varied widely and exhibited multiple modes indicative of protracted batch spawning. A review of the few other studies of trout-perch revealed periodic fluctuations in sex ratio of adults, which in light of our evidence of periodicity in abundance suggests the potential for sex-ratio-mediated intrinsic population regulation. Despite the introduction of numerous invasive species in Lake Erie, trout-perch remain one of the most abundant benthic invertivores and the population is relatively stable.

Reproductive condition and ovarian atresia in the common kilka (<i>Clupeonella cultriventris</i>) from the Caspian Sea years after a dramatic outbreak of the comb jelly fish (<i>Mnemiopsis leidyi</i>)

SUMMARY: To assess the reproductive condition of the common kilka, Clupeonella cultriventris, the somatic condition and reproductive characteristics were studied by histological analysis. A total of 800 specimens from the Bandar Anzali coast on the Caspian Sea were sampled. The gonadosomatic index (GSI) for females and males attained maximum values in May in the first period of sampling and in March-April in the second period, suggesting temporal variations in spawning activity. The pattern of oocyte frequency distribution demonstrated that the common kilka is a batch spawner with group-synchronous oocyte development. The estimated relative batch fecundity was 6718 oocytes g–1. A low level of atresia (4.7%) during the spawning season showed that this species was in optimal somatic condition. This weakens the hypothesis that abundance of the ctenophore (Mnemiopsis leidyi) in the Caspian Sea, as a food rival for kilka, influences the body condition and subsequently the reproductive capability of this species.

Non-indigenous armoured catfish in Vietnam: invasion and systematics

The occurrence of non-indigenous armoured catfish Pterygoplichthys aff. pardalis from the Dinh River basin (Khan Hoa Province, Vietnam) is reported. We provide data indicating that this may be a naturalised population and present information on the fish reproduction, which points to possible batch spawning. Potential threats posed by the armoured catfish to the native habitat are discussed. Morphometric traits do not form discrete clusters, patterns of the body colouration (the main diagnostic character of these species) are very diverse and largely embrace those of different species. We suggest that the systematics of the genus should be revised.

Description of the ovarian follicle maturation of the migratory adult female bulatmai barbel (Luciobarbus capito, Güldenstädt 1772) in captivity.

The study aimed to investigate the maturation process of ovarian follicles and ovary structure of migratory form of female Bulatmai barbel (Lucioarbus capito). The histology of oogenesis coincided with that known from most teleosts. The ovarian structure was found to be cytovarian. The development of the oocytes is started from early May along with spawning and the degeneration of matured oocytes. The oocytes' development continues during summer and early fall and the ovary undergoes a dormant period in fall and winter. In the next spring, the next phase of oocyte development started along with the rising of water-temperature. During May and June the development of the oocytes is completed and the final maturation can occur if the environmental conditions are suitable. The Gonadosomatic Index values show a concordance with the oocyts maturation in the ovaries. The reproductive strategy, with long spawning periods during spawning season, found to be batch spawner with asynchronous oogenesis pattern. The results show that it can be matured while captivity.

Gonadal recrudescence and induced spawning inBarbus altianalis

Gonadal recrudescence in Barbus altianalis from River Nile, Jinja (33°05E; 0°45N) Uganda was studied prior to induced spawning. Oocytes in B. altianalis were found to develop in cohorts suggesting batch spawning throughout the year with pronounced spawning activities coinciding with rainfall peaks of April and September. There was a strong positive correlation between rainfall and gonadosomatic index (rS = 0.75, P = 0.008). B. altianalis had low fecundity (6.0 ± 2.0 per gram) and large-sized eggs (2.97 ± 0.1 mm). Induced spawning was successful with exogenous hormones and water current. Results from this study suggested that total striping may not be appropriate, but larger eggs would confer high survival of offsprings under optimal conditions. The success registered in induced spawning of B. altianalis provides a breakthrough in seed production for multiplication and culture of this economically important fish species.

Escala de madurez gonadal del jurel Trachurus murphyi Nichols 1920

This paper describes the macroscopic scale of gonad maturity stages of Jack mackerel Trachurus murphyNichols 1920, validated by microscopic studies, and being used in Peru,. A scale of six maturity stages are identified for females and males, ranging from stage 0 (virgin) to stage V (recovery in females, post-spermiation in males). The gonads of 350 specimens were analyzed. These specimens were collected as part of a pelagic fishery monitoring programme and during pelagic stock assessment surveys between 2006 and 2009. Virgin individuals are classified as stage 0 (virgin), which draws the distinction between (non-reproductive) juveniles and (reproductive) adults in stages I to V. The advantages of using the validated stages of gonad development of Jack mackerel T. murphyiare discussed and are compared to other scales of maturity stages proposed for other species in the same family. The analysis of the microscopic characteristics of the ovaries confirms that Jack mackerel is a batch spawner, which has already been described by other authors.

Growth, Development, and Reproduction in Gulf Corvina (Cynoscion othonopterus)

Gulf corvina, Cynoscion othonopterus, is a vital component of commercial fisheries in the northern Gulf of California, but a lack of information on life history parameters have thus far prevented a comprehensive stock assessment. In this project, 530 specimens of Gulf corvina were collected from commercial gill net fisheries in the Colorado River Delta region in Sonora, Mexico, to characterize population structure, age and growth patterns, age and size at sexual maturity and batch fecundity. Fish ranged from 145 mm to 1013 mm in total length and from 1 to 8 years of age. Von Bertalanffy growth model parameters were: L∞ = 1006 mm, k = 0.255/yr, t0 = 0.616 years. Growth rates of Gulf corvina did not differ significantly between sexes, although females were predicted to reach a larger asymptotic length. Mean size (Lm50) and age (Am50) at sexual maturity from histological analyses of gonad tissues was 294.7 mm and 2.3 years for females and 267.5 mm and 2.0 years for males. Maturity estimates from otolith analyses did not differ between sexes and were similar to maturity estimates derived from gonadal histology, indicating that energy allocation shifts from growth to maturation and reproduction after year two. Batch fecundity ranged from 240,394 to 1,219,342 eggs with a mean of 684,293 eggs per spawn, and was correlated to both total length and gonad-free body weight. The distribution of oocyte diameters and oocyte stages indicate that Gulf corvina is a multiple batch spawner with asynchronous oocyte development and indeterminate annual fecundity.

Pemphigus familial

Liver weight, relative condition (Kn), and somatic energy content have proven useful for predicting reproductive potential of fishes. Such proxy measures are advantageous in that they are easier to measure directly than fecundity and can often be measured in advance of spawning. We explored the utility of simple as well as more detailed measures of reproductive output in a laboratory experiment with black sea bass (Centropristis striata), an iteroparous, batch spawning protogynous hermaphrodite that may exhibit both determinate and indeterminate fecundity patterns within its geographic range. Wild fish were collected in fall, well ahead of spring-summer spawning, from two locations (Woods Hole, MA; Panama City, FL) representing mid-Atlantic and Gulf of Mexico stocks. To obtain a range in condition, fish were subject to either a high or low feeding regime for 4–5 months. During the experiment, length, weight, and bioelectrical impedance analysis (BIA) of individuals were monitored monthly. At the end of the experiment, additional individual measures taken included: relative gonad, liver, and viscera weights, absolute energy density, sex and maturity. As planned, these feeding treatments produced a range in sizes, fish of both sexes were developing or spawning capable, and the high ration group had higher Kn. This provided sufficient contrast to explore predictive relationships between total gonad energy (TGE) and terminal or prior biological measures. Examining multiple models with Akaike Information Criteria showed that final TGE was estimated with highest precision from a model including final sex, gonadosomatic index, length, Kn and liver energy density (89.1% deviance explained). The best model using nonlethal measures included BIA measured phase angle (PA) one month earlier, but much precision was lost (31.0% deviance explained). The explanatory power of PA, Kn, fish size, and stock also changed during the experiment, reflecting differences in the timing and magnitude of energy allocation and the difficulty in applying non-lethal measures to estimate TGE precisely in this species. Different energy allocation pathways were also apparent by stock. By the end of the experiment, mid-Atlantic black sea bass allocated more energy to liver and gonad whereas Gulf black sea bass allocated more energy to soma and viscera. We postulate that such intraspecific differences are adaptive in terms of the very different environmental conditions experienced by and the reported differences in spawning strategies by each stock, but this is rarely demonstrated in fishes and warrants further investigation.

Reproduction of the Brazilian snapper, Lutjanus alexandrei Moura & Lindeman, 2007 (Perciformes: Lutjanidae), off the northern coast of Pernambuco, Brazil

Reproductive aspects of the Brazilian snapper Lutjanus alexandrei, were characterized, including a description of the development of oocytes and spermatogenic cells, size at first sexual maturity, and fecundity. A total of 540 fish were analyzed with 250 having their gonads sectioned to allow microscopic evaluation. Six maturity stages were identified for females and males: immature, maturing, mature, spawning, spawned, and resting. Fish standard length (SL) varied from 13.0 to 28.3 cm and sex ratio was 1.6 males: 1.0 females. Monthly distributions of mean Gonadosomatic Index (GSI) and maturity stages suggest that spawning occurs mainly in a protracted period, during the warmer months, from November to March. The size of first sexual maturity was estimated at 17.1 cm SL for females and 16.8 cm SL for males. Oocyte development suggests that L. alexandrei exhibits a multiple batch spawning behavior and batch fecundity varied from 34,000 to 324,000 oocytes.

Comparative reproductive biology of Sciaenidae family species in the Río de la Plata and Buenos Aires Coastal Zone, Argentina

A comparative analysis on various aspects of the reproductive biology of 7 Sciaenidae family species was done. In addition the reproductive parameters needed for stock assessment models were provided. The research covered the analysis of the duration of the breeding season and the estimation of reproductive variables such as size at maturity, fecundity and spawning frequency. When all species were considered together, some aspects of reproduction were similar, regarding the reproductive strategy; all species are batch spawners with indeterminate fecundity and an extensive reproductive season (approximately six months) except for Pogonias cromis, which showed a more limited spawning season (three months). With regard to reproductive potential, wide differences in fecundity values mainly due to the different sizes attained by each species were observed (range in batch fecundity values between 5000 and 2,800,000 hydrated oocytes). However, when relative fecundity was compared, average values were generally similar, ranging approximately between 150 and 200 hydrated oocytes per female gram. Pogonias cromis is the exception within this group, because the mean relative fecundity ranged between 75 and 98 hydrated oocytes per ovary-free female gram. This difference may be a consequence of the greater oocyte size reached by P. cromis eggs (1100–1400 μm) compared to the rest of sciaenid analysed (750–900).