Partial Spawning Research Articles

Assessing the temporal isolation barrier between two closely related species of the genus Fissurella off the southwestern coast of South America

ABSTRACT Knowledge of the reproductive isolation mechanisms that prevent gene flow between species is essential for understanding the process of speciation. In this study, we investigate the spawning periods in Fissurella cumingi and F. latimarginata, two closely related sympatric species of keyhole limpets with external fertilization, as a potential prezygotic barrier between them. The reproductive cycle was assessed in two distinct locations in northern Chile using the gonadosomatic index (GSI) and gonadal histology. Species, locality, and sex were designated as predictive variables, while average GSI values, as well as those of partial and total spawning, were considered dependent variables. Both species exhibit a continuous gametogenic cycle throughout the year, characterized by multiple spawning events. A generalized linear model (GLM) factorial ANOVA design revealed that neither species, locality nor sex were significant factors with respect to the GSI and partial spawning scores. However, sex was found to be the only significant factor related to total spawning. No significant interactions were observed among predictive factors. These findings suggest that reproductive periods may not serve as effective barriers to gamete encounters between species. Our study prompts questions about how closely-related externally-fertilizing species maintain reproductive isolation.

Reproductive biology of goldstripe sardinella (Sardinella gibbosa) landed at TPI Pantai Labu Deli Serdang, North Sumatra

Goldstripe sardinella (Sardinella gibbosa) is a small pelagic fish found in Pantai Labu, Malacca Strait. Goldstripe sardinella has an important economic value and is in great demand by the local community because it has an affordable price so that it becomes the main target catch of fishermen. Increased fishing effort and demand are feared to have decreased population. This study aimed to determine the reproductive biology of Goldstripe sardinella (S. gibbosa) landed at the TPI Pantai Labu Deli Serdang, North Sumatra Province. This research was conducted from September to November 2022. The method used was a random purposive sampling method with an interval of one month. The number of fish samples was 209 fish with a total length of 134-208 mm and a total weight of 25.01-99.89 g. The sex ratio between males and females is 0.82:1 indicating the ratio is balanced. The GSI values were concurrent from GML I-GML IV with an overall GSI value of 2.39%, fecundity ranged from 1548-30858 grains with a partial spawning pattern.

LENGTH-WEIGHT RELATIONSHIP AND CONDITION FACTOR OF THE WHITEMOUTH CROAKER Micropogonias furnieri (ACTINOPTERYGII, SCIAENIDAE) CAPTURED IN THE NORTHEAST OF BRAZIL

Length-weight relationships (LWRs) and relative condition factor are of great importance in fishery assessment studies since it providesinformation about the growth of the fish, its general wellbeing, and fitness in a marine habitat. This study estimated length-weight relationship and condition factor for whitemouth croaker Micropogonias furnieri captured in Pirambu-SE, northeast from Brazil. A total of 1333 specimens were analyzed, from March 2019 to March 2020. Whitemouth croaker showed negative allometric growth resulting in β1: 2.7697. The condition factor varied between months, such as September and between January and February, demonstrating a possible partial spawning

Effect of Exogenous Hormones in Combination with Dopamine Antagonists in Breeding of Indian Major Carps

Effect of intraperitoneal injection of different inducing agents viz., pituitary gland (PG) extract, PG + domperidone (DOM), PG + pimozide (PIM) (all in two split doses) and ovaprim (in single dose) on ovulation and spawning in three Indian major carps such as rohu, catla and mrigal were investigated. Injection of PG extract alone to rohu, catla and mrigal resulted in ovulation of 93.3, 90.6 and 100% individuals, respectively. The spawning success achieved was 91.6, 71.8 and 100% in rohu, catla and mrigal, respectively. PG at the same dose alongwith dopamine antagonist (DOM/PIM) resulted in ovulation in all the individuals of the three species of carp but partial spawning to complete spawning was observed in them. The present study revealed that the domperidone alongwith hormonal suspension is more effective in rohu and mrigal, while pimozide with hormonal suspension is more effective in catla.

Gonadal characterization of the Amazonian fish Serrapinnus kriegi (Characidae: Cheirodontinae).

The knowledge of the testicular and ovarian morphology of a particular fish species is of paramount importance. Such analyze enables the development of studies and techniques aiming the improvement of their reproduction, management, commercialization and even their conservation. This study performed the ovarian and testicular characterization of the ornamental Amazon fish Serrapinnus kriegi. A total of three males and three females had their gonads analyzed by optical microscopy. Females present ovaries filled with oocytes in asynchronous development, indicating partial spawning in the species. Moreover, the micropyle and micropilar cell formation was observed in primary growing oocytes, representing a precocious oocyte development; and the zona radiata in the final vitellogenic oocytes is thicker than other related species, evidencing the development of a better protection to the embryos in function of the waters' turbulence that characterize it spawning sites in the Amazonian streams. The male specimens' present anastomosed tubular testes with unrestricted spermatogonia spread along the entire seminiferous tubules. The present data elucidate the dynamic of spermatogenesis and oogenesis of an ornamental Amazonian species, through the description of the male and female germ cells development.

Interspecific variation in fish spatial synchrony relates to reproductive traits in a highly fragmented river

AbstractSpatial synchrony occurs when the abundance of populations in different locations rise and fall together. This pattern is caused mainly by dispersal and spatially correlated environmental stochasticity. The levels of spatial synchrony can vary between species, yet little is known about which species traits can explain this interspecific variation. In addition, traits may have different degrees of influence on spatial synchrony levels because of their differences in plasticity. We hypothesized that conservative traits—reproductive and morphological—will best explain interspecific variation in synchrony, while those that may vary according to the environment—feeding and habitat preference—will be weakly related to this interspecific variation. We evaluated the spatial synchrony of freshwater fish species in a highly fragmented river in the Neotropical region and related the levels of synchrony to seven predictors: diet, reproductive traits (migration, fecundation, parental care and spawning), position in the water column, niche breadth, body size, body shape and average temporal occurrence of each species. The fish species showed low levels of spatial synchrony but a high interspecific variation (correlation values ranging from −0.11 to 0.41). We found that this variation was mainly related to species' reproductive traits, that is, sedentary species with partial spawning and without parental care had higher mean spatial synchrony than species with the opposite characteristics. In contrast, more plastic traits (diet and habitat preferences) were poor predictors of mean spatial synchrony. We speculate that, despite the low spatial synchrony found, if extreme impacts continue to occur in the basin at the regional scale, it may negatively affect local fish populations in a synchronous manner, resulting in increased risk of simultaneous declines.

Reproductive aspects of the dwarf cichlid Apistogramma agassizii under captive conditions

Apistogramma agassizii is a native fish from the Amazon basin, which is of great interest for fishkeeping and is supplied to the retail trade from extractivism. Knowledge about the reproductive characteristics of this fish is fundamental to successful breeding. Objective: This work aimed to study the behavior and reproductive performance of this species in white and black aquariums. A total of 16 pairs were used, 8 in each treatment. The system had water recirculation, with fresh and inert food supply. Result: The fish demonstrated parental care, more accentuated by the female and partial spawning. The same coloration pattern was observed in both treatments, with coloration intensifying only during spawning. The eggs were adhesive and U-shaped/oval. The females followed the larvae, even after they left the nests, and attacked the males when they approached the offspring. Males exhibited territorial behavior. No significant differences were observed for the following parameters studied: largest and smallest egg size, spawning weight, absolute fecundity, number of hatched larvae, and hatchability rate. Conclusion: This study found that the fish are prolific and show good reproductive rates in conditions of captivity; thus, they are suitable to rear for the ornamental fish trade.

Biological aspects of brown-marbled grouper (Epinephelus fuscoguttatus) from Taka Bonerate National Park, District of Selayar Islands, South Sulawesi, Indonesia

Abstract. Fatma, Mallawa A, Najamuddin, Zainuddin M, Ayyub FR. 2022. Biological aspects of brown-marbled grouper (Epinephelus fuscoguttatus) from Taka Bonerate National Park, District of Selayar Islands, South Sulawesi, Indonesia. Biodiversitas 23: 1140-1153. Knowledge regarding biological aspects of fishes such as the brown-marbled grouper can provide important information for fisheries management. This research was conducted from February 2020 to February 2021 to determine the length-weight relationship, condition factor, gonad maturity stage and spawning pattern, size at first maturity and feeding habits of brown-marbled groupers in Taka Bonerate National Park. The sample caught comprised 1042 brown-marbled groupers with a total length (TL) range of 23-97 cm and a weight range of 0.5-17.6 kg. The length-weight equation was W: 0.0001?L2.5955 (R²: 0.8935). For male brown-marbled grouper (n: 569), TL range was 47-97 cm, weight range 1.65-17.60 kg, regression equation W: 0.0002?L2.4731 (R²: 0.7716), condition factor range 0.56-2.36 (mean 1.236±1.019), and length at first maturity 66.34 cm. For female brown-marbled grouper (n: 473) TL range was 23-73 cm (mean 46.84 cm), weight range 0.50-6.6 kg (mean 2.23 kg), regression equation W: 0.0007?L2.1057 (R²: 0.7416), condition factor range 0.55-2.17 (mean 1.225±1.018), and length at first maturity 45.43 cm. The growth pattern was negative allometric with regression coefficient b < 3 for both sexes separately and combined. The majority of both male and female fish caught had mature gonads with indications of a partial spawning pattern. The fish diet was carnivorous, predominantly piscivorous (74%), with gut contents comprising 64% unidentified fish and 26% unidentified decapod crustaceans. Over-exploitation of fish can cause negative impacts on populations, so the relationship between length and weight, condition factors and maturity level gonad of fish can be used in fisheries management.

Reproductive aspects of the dwarf cichlid Apistogramma agassizii under captive conditions

Apistogramma agassizii is a native fish from the Amazon basin, which is of great interest for fishkeeping and is supplied to the retail trade from extractivism. Knowledge about the reproductive characteristics of this fish is fundamental to successful breeding. Objective: This work aimed to study the behavior and reproductive performance of this species in white and black aquariums. A total of 16 pairs were used, 8 in each treatment. The system had water recirculation, with fresh and inert food supply. Result: The fish demonstrated parental care, more accentuated by the female and partial spawning. The same coloration pattern was observed in both treatments, with coloration intensifying only during spawning. The eggs were adhesive and U-shaped/oval. The females followed the larvae, even after they left the nests, and attacked the males when they approached the offspring. Males exhibited territorial behavior. No significant differences were observed for the following parameters studied: largest and smallest egg size, spawning weight, absolute fecundity, number of hatched larvae, and hatchability rate. Conclusion: This study found that the fish are prolific and show good reproductive rates in conditions of captivity; thus, they are suitable to rear for the ornamental fish trade.

Reproduction aspect of tiger fish (Datnioides polota hamilton) in musi river South Sumatera

The research about the aspect of Tiger fish reproduction (Datnioides polota Hamilton) in the Musi River South Sumatera has been carried out in March to May 2011. This research aims to determine the reproduction aspect of Tiger fish (Datnioides polota Hamilton) which covers the lenght-weight relationship, sex ratio, maturity level of the gonads, gonad maturity index, fecundity and egg diameter. The sampling was carried out by purpossive sampling method using belat that is a net with 3 mm mesh size. Belat put in to cover the river bank along the 30-70 m with hight of nets ranging from 1.5-2 m, and the fish that catch by fisherman using another net. The sampling was conducted from March to May and obtained 86 fishes. The result of this research showed that the growth pattern of Tiger fish (Datnioides polota Hamilton) is positive allometric. Sex ratio of Tiger fish is a whole in a state that is not balanced is the number of male fish more than the female fish with a range of gonadal maturation index between 0.064 % to 9.954 %. Tiger fish fecundity ranged from 33.925 to 350.268 eggs and have gradually spawning patterns (partial spawning).

Fish reproductive activity reveals temporal variations predominating spatial heterogeneity in maintaining high functional diversity of a Neotropical reservoir

AbstractThe reproductive activity of the fish assemblage in a large Neotropical reservoir was evaluated by surveying the occurrence of ichthyoplankton in response to spatial and temporal variation in environmental factors. Fish reproduction was investigated by capturing larvae along representative spatial gradients in the main body (longitudinal) and arms (lateral) of the reservoir. After identification, the captured larvae were classified into different groups according to the functional traits of their parental stock. Sampling occurred monthly at night from October to March over five reproductive periods between 2009 and 2016, using conical‐cylindrical plankton nets with flowmeter. Water samples were taken simultaneously allowing the measurement of environmental factors related to reproductive activity. The relationship between the environmental factors and the functional traits was assessed using RLQ and fourth‐corner analyses. An evaluation of 51,995 larvae revealed there was greater larval abundance in the lacustrine and transition zones of both longitudinal and lateral gradients. Occurrences often correlated with temporal instead of spatial gradients. Higher rainfall correlated with abundances of detritivorous and migratory species. Higher water levels correlated with higher abundances of non‐native species, species without parental care, with external fecundation, and partial spawning. Dry periods, with lower water and higher dissolved oxygen, correlated with higher abundances of insectivores and sedentary species. Although the presence of a dam‐free stretch of river upstream of the reservoir had a positive influence on fish larvae in the fluvial zone, the results did not show differentiation along either gradient. Thus, the composition of the functional groups of fish species that reproduce in the Itaipu Reservoir appears to be predominantly influenced by the temporal variation in environmental factors rather than the formation of spatial gradients.

Reproductive aspects of <i>Chiton virgulatus</i> in Bahía de La Paz, Gulf of California, Mexico

This study analyzed the reproductive cycle of Chiton virgulatus and its relationship with air temperature (AT) sea and surface temperature (SST), photoperiod, and tidal cycle (TC) in Bahía de La Paz, in the coast of the Gulf of California. Monthly samples were collected from September 2008 to September 2009. The parameters recorded included total length, total weight, and gonad weight of each organism; the gonad was processed using a histological technique, and the gonadal index and length at first maturity (L50) were estimated. C. virgulatus displays partial spawning with a reproductive peak in summer and autumn (July to December). The frequency of ripe organisms was associated with rises in SST (30.6 ºC), AT (29.9 ºC), and TC (68 cm, high tidal), while photoperiod (longer days) regulated the frequency of developing organisms. The length at first maturity was 29.7 mm. Chiton virgulatus is a polyplacophoran species in which high temperatures and high tides influence reproductive timing, while an increase in daylight boosts gonad development.

Comparative analysis of the reproductive activity of Leporinus piau (Characiformes: Anostomidae) in lentic and lotic environments

Abstract In this study, we determined the main reproductive parameters of piau gordura, Leporinus piau, in two sections of the São Francisco River basin. Between May 2015 and April 2016, a total of 573 specimens were captured from a lentic environment (section 1), the Três Marias Reservoir (TMR), and a lotic environment (section 2), downstream of the TMR at the confluence of the São Francisco River (SFR) with the Abaeté River. Analysis of reproductive activity showed that L. piau from both sections reproduced, but females and males from section 1 exhibited higher total length, body weight, Fulton condition factor, and gonadosomatic index values, as compared to section 2. Sexual dimorphism was evident in the species, with females being larger than males. Moreover, males reached first gonadal maturation at a smaller size than females. The peak maturation/mature stage was observed in November/April for females and males in section 1 and in November/December in section 2, coinciding with high temperatures and precipitation in the region. In both sections of the river, L. piau exhibited the typical characteristics of partial spawning, with a prolonged spawning period, and preferential reproduction in lentic environments.

Reproductive patterns of the black starry sea urchin Arbacia stellata in Punta Banda, Baja California, Mexico

AbstractWidely distributed species such asArbacia stellataadjust patterns of their life history according to local conditions. In the present study the reproductive cycle of this species was analysed throughout a sampling year. Gonadal development cycle, sex ratio, actual fecundity and oocyte size distribution were characterized and the relationship of these reproductive characteristics with environmental variables such as sea surface temperature, photoperiod, chlorophyllaand net primary production evaluated. Our results showed thatA. stellatais a gonochoric sea urchin. Gametogenesis was classified into six stages for both sexes (immature, growth, pre-maturity I, pre-maturity II, mature and spawning) and no synchrony was observed for the gonads between individuals. The female to male ratio was close to 1:1 in most months. The gonadosomatic index (GSI) showed significant differences between sexes or months; however, the highest values were observed during spring, with positive correlation with chlorophylla. No significant differences were observed in the maturity index (MI) between sexes, with a positive correlation with temperature but negative with chlorophyll. Actual fecundity showed wide variations throughout the year and correlation with chlorophyllaand temperature. Oocyte size distribution was unimodal and the predominant frequency was that of mature oocytes. The reproductive cycle ofA. stellatahas a semi-continuous pattern for both sexes and partial spawning throughout the year in the sampling site. We observed nutrient assimilation in the gonads during spring and a larger reproductive activity from late summer to early winter.

Embryological development of the high-altitude killifish Orestias ascotanensis Parenti 1984 (Teleostei: Cyprinodontidae)

Orestias ascotanensis Parenti is a critically-endangered fish species endemic to the Ascotan salt pan springs. Given the importance of reproduction and early development in effective conservation of fish populations, this study describes the embryonic development of O. ascotanensis under laboratory conditions. Between 2014 and 2015, 50 individuals were captured and maintained under controlled conditions, including temperature, photoperiod and feeding regimen, to induce spawning for artificial fertilization. Females were subjected to hormone therapy with Ovaprim®. Water temperature was maintained at 20 °C (± 1 °C), conductivity at 2800–3600 μS·cm−1 and photoperiod at 16:8 (light hours: dark hours). Males showed changes in color and courtship behavior, and females developed a slightly bulging belly. Eggs were 1.55–2.5 mm in diameter, with abundant yolk and dozens of adhesion filaments. Embryonic development lasted 14–18 days; it was divided into five periods, which can be sub-divided into 21 stages, from fertilization to hatching. O. ascotanensis showed indications of partial spawning species, including oocytes at different stages of development, relatively large eggs as compared to adult fish length and low batch spawning. Characteristics such as partial spawning, highly-pigmented eggs and larvae and advanced larval development at hatching could be adaptations to the extreme conditions of the salt pan springs, including high levels of ultraviolet radiation and salinity as well as significant daily temperature changes.

Sex Differentiation and Gonadal Development of striped snakehead (Channa striata Bloch, 1793)

The striped snakehead Channa striata is a predatory fish whose life cycle still holds many mysteries. One of the obstacles to cultivating this fish is the difficulty of obtaining male broodstock. This study aimed to examine the sexual development of C. striata. Such information will be of benefit not only for the cultivation of C. striata, but also for sustainable management and exploitation of wild populations. Samples were collected from June to September 2017 in the inland waters (rivers and canals) of Barru and Bantaeng Districts, South Sulawesi, Indonesia. Gonads were observed both macroscopically and microscopically including gonad morphology, acetocarmine solution staining, and histology. We found that female C. striata were larger and more numerous compared to males in the same population (2 female:1 male). We identified five different oogenesis phases in C. striata: immature, maturing, mature, spawning (partial spawning), and post-spawning (spent). Some individuals of standard length 81-229 mm had an intersex (ovotestis) type gonad. In fish of standard length 110-241 mm, two types of gonads were found: a pair of ovaries suspected to be undergoing apoptosis, and a pair of developing testes. Two pairs of gonads were also found in an adult of length 381 mm, but both pairs were ovaries, of which one was in mature stage (ripe), the other undergoing apoptosis. This study suggests that Channa striata is at least potentially hermaphroditic, and its gonads can undergo a differentiation phase. We recommend further study on the genetic mechanisms and/or environmental influences which determine gonad development and sex differentiation in C. striata.

Reproductive biology of Hyphessobrycon eques (Characiformes: Characidae) in Southern Pantanal, Brazil.

Population and reproductive aspects allow the knowledge and understanding of population dynamics and the influence of environmental factors, in addition to ensure the success of a species continuity. Thus, the aim of this study was to analyze population and reproductive traits of the species Hyphessobrycon eques in southern Pantanal, Brazil. Monthly samplings were conducted from February/2009 to January/2011, with 617 individuals analyzed, being 365 females and 262 males. A similar form of distribution in length and weight between the sexes was observed. There was no significant variation in sex ratio over time, with higher proportion of females during the entire sampled period. Both sexes presented a angular coefficient of Weight/Length (b) relationship greater than 3, with speed of increase in weight greater than in length. For females, a long reproductive period was observed, with greater reproductive intensity from January through June. No significant correlation was observed between the Gonadosomatic Index (GSI) and the average temperature, rainfall and river level, despite the fact that reproductive activity occurs in autumn/winter, when there are favorable conditions due to flooding. The size at first maturation (L50) was 20.2 mm, with confidence interval varying from 19.7 through 20.7 mm. The average fecundity was 191.9 oocytes/females and was significantly related to the standard length and total weight (g), demonstrating a relation with energy accumulation to invest in reproduction. The long reproductive period, intensified by partial spawning, higher proportion of females and low L50, show that the species has strategies necessary for survival and rapid population growth, common in small species characterized as r-strategists.

Fecundidad en gónadas maduras de Haliotis fulgens y Haliotis corrugata (Vetigastropoda)

Background: The term fecundity in abalone is defined according to an estimate of its absolute fecundity, which is the number of mature oocytes present in the gonad, or as potential fecundity, i.e., the total number of oocytes present in the gonad. In Mexico, few studies have estimated the fecundity of mollusks and these have been performed on gonads in different phases of gonadal development, obtaining values that are very different or overestimated, for example, values ranging from 80000 to 22 million oocytes in a gonad. Goals: Estimate the fecundity of Haliotis fulgens (blue abalone) and Haliotis corrugata (yellow abalone), using ma­ture gonads and a particle counter (Multisizer 3) to count only mature oocytes. Methods: Each month from October 2011 to February 2013, 30 adult organisms of each species were collected in two localities of Baja California Sur, Mexico (La Bocana and Bahia Tortugas). A histological analysis identified those that were mature females. To obtain the number of eggs per gram, triplicate oocyte counts were performed in a coulter counter Multisizer 3, in a solution of 4 g wet weight of mature oocytes diluted to 50 mL of filtered seawater (μm). Absolute fecundity was calculated by multiplying the total weight of the gonad by the number of mature oocytes present in one gram of oocytes. Results: The fecundity in La Bocana was found to be 2x106 eggs in H. corrugata and H. fulgens, while in Bahia Tortugas it was 4x106 eggs in H. fulgens. Conclusions: This study suggests that estimating absolute fecundity in species with partial spawning, such as H. fulgens and H. corrugata, should be per­formed on all females regardless of the degree of gonadal development. However, only mature oocytes should be considered as an indicator of absolute fecundity. Therefore, the use of an apparatus that counts and measures mature oocytes, such as a particle counter, facilitates and guarantees a good estimate of fecundity.

Annual reproductive cycle and condition index of Mactra corallina (Mollusca: Bivalvia) from the north coast of Tunisia

ABSTRACTThis work aims to examine the reproductive cycle of the bivalve Mactra corallina inhabiting the Gulf of Tunis (Tunisia). Histological analysis indicated that the reproductive cycle is composed of six stages and was synchronous between sexes. Gonadal development began in January. From April to July, an increase in temperature (from 16 to 28°C) and a rise in chlorophyll a (from 3.25 to 6.35 mg/L) marked the period of sexual maturity in both sexes, which was also confirmed by an elevation in condition index (CI). Partial spawning started in April for males and in May for females, peaking in late summer indicating a prolonged reproductive period. The reproductive cycle of M. corallina finished with an inactive stage during autumn. From the total number of animals used in this study, we identified 104 females (52%) and 96 males (48%) corresponding to a sex ratio 1:0.92 that did not differ significantly from a 1:1 ratio.

Influence of different microalgal diets on gonadal development of the carpet shell clam Ruditapes decussatus broodstock

Studies considering broodstock conditioning of Ruditapes decussatus mostly used flagellates and diatoms for feeding, mainly Isochrysis galbana and Chaetoceros calcitrans, respectively. The present study evaluated the effect of different microalgal diets on gonadic maturation of R. decussatus including three microalgae species (C. calcitrans, Tetraselmis suecica, and Nannochloropsis oculata) which were used to prepare six diets: three monospecific and three bispecific mixed diets at a proportion of 1:1. Clams were daily fed at a ratio of 1% dry weight of algae/live weight of clam and unfed treatment was used as control. Results showed that clams fed C. calcitrans alone or mixed with T. suecica attained earlier full maturity with the highest response to spawning induction (after 34 conditioning days) and largest proportion in the partial spawning phase for both, followed by T. suecica alone after 48 days. In contrast, N. oculata alone or mixed diets demonstrated poor performance for gonadal maturation. Unfed treatment did not show any sign of maturation. The results indicated that T. suecica has high conditioning potential like C. calcitrans and their mixture gave the highest benefit. Therefore, T. suecica can be recommended for R. decussatus broodstock conditioning.