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The spotted rose snapper (Lutjanus guttatus) is a commercially important species that provides economic income to small-scale fisheries in the Pacific coastal regions of Guatemala; however, there are no studies on this species that establish a baseline of knowledge on their reproductive aspects and potential management measures. The present study was carried out to obtain the first knowledge on the reproductive behavior of this resource, which will contribute to the establishment of future management strategies for the fisheries. Aspects of gonadal-maturity phases and reproductive indicators such as the condition factor, gonadosomatic index, and temporal oocyte diameter were analyzed to estimate reproductive development and the size at first maturity. The results suggest that the spotted rose snapper has two well-defined reproductive periods - from October to December and March to May. These periods were closely related to temperatures that ranged from 29 to 31°C. In addition, according to the monthly monitoring of the oocyte diameter density distribution, it is suggested that spotted rose snapper in the region could participate in up to three spawning events during the reproductive season, with gamete development occurring throughout most of the entire study period. The first size at maturity was a total length (TL) of 33.49 cm (confidence interval = 30.95-36.14 cm). This information is important for sustainable fishery management and provides a baseline for future research. [ABSTRACT FROM AUTHOR]

The reproductive biology of the invasive blue crab Callinectes sapidus was studied in the Thermaikos Gulf (Northwest Aegean Sea, Eastern Mediterranean). In the two-year survey, 5698 (2897♂/2801♀) crabs were caught with the use of fyke nets. Total sex ratio (♂/♀) reached equality (1.03:1). The female blue crab exhibited a protracted reproductive period. Mature and ovigerous females exhibit short migratory movements from estuarine and inshore waters, where the population mostly congregates (0–3 m), and move to slightly deeper waters (1–3 m) up to 9 m for spawning. A total of 340 ovigerous females were caught. Their number varied both spatially and temporally; they were observed for a 7-month period (April to October) with a clear peak in July–August and at a 3 m depth gradient corresponding to ≈60% of the total number of ovigerous females caught in both years. Size at first sexual maturity (CW50) was estimated at 113.1 mm CW. Average fecundity was ≈790,000 eggs. Experimental trawling showed that inshore waters (<1 m) in the estuaries serve as nursery areas for juveniles. Defining the spatiotemporal and bathymetrical distribution of ovigerous females in any invaded coastal habitat could be considered key information for the implementation of a management policy for the species. [ABSTRACT FROM AUTHOR]

The objective of the current study was to describe the female reproductive characteristics of populations of the non-indigenous shrimp Penaeus latisulcatus off the Egyptian Mediterranean coast. P. latisulcatus was sampled from the commercial catch of Boughaz El-Maadiyah's landing center off the Mediterranean coast between July 2020 and June 2021. This study focused on describing maturity stages, calculating the gonadosomatic index (GSI), determining the spawning season, and measuring the size at first maturity of female P. latisulcatus. The stages of ovarian development were divided into six stages; i.e., immature, early maturing, late maturing, nearly ripe, ripe, and spent. A prolonged spawning season was identified, extending from the summer season to autumn and showing a peak in August. The GSI followed the same pattern of ovarian maturation and confirmed the spawning season of P. latisulcatus. As revealed, 50% of female individuals attained maturity at a total length of 11.34 cm. Hence, this study provides fundamental and helpful information for understanding the reproductive dynamics of P. latisulcatus on the Egyptian Mediterranean coast as a new habitat for its propagation. This information also helps in providing the proper management of fisheries and conservation of this shrimp species, which can be useful for aquaculture processes as well.

Abstract This study investigated the reproductive traits of the hermaphroditic four-finger threadfin, Eleutheronema tetradactylum, along the coasts of Thailand during January to December 2021. Fish samples were collected from Pattani Bay, Thailand to assess the sex ratio, gonadosomatic index (GSI), maturity stage and fecundity. Additional fish samples were also collected from other areas to evaluate the length and weight at first sex change (Ls50 and Ws50) and length at first maturity (Lm50). The overall sex ratio for male and female was 1:0.69 with male being predominant throughout the year. Threadfin fish spawn the whole year round with peaks during moderate rainy and heavy rainy seasons. Histological examination confirmed its protandrous hermaphrodite posing multiple spawning habits. The average fecundity was 1.85 × 105 ± 1.05 × 105 eggs and positively related with standard length, body weight, gonad weight, and egg diameter (p

Horse mackerel is a semi-pelagic fish widely distributed in the eastern Atlantic, where it represents a species of interest for fisheries and is subject to intense exploitation, leading to its global classification as a vulnerable species by IUCN. In the Northwestern (NW) Mediterranean Sea, the knowledge of their distribution, abundance and main biological parameters is fundamental to achieve their sustainable exploitation and contribute to the ecosystem approach to fisheries management. The time series (2009–2020) data set analyzed in this study came from two geographical subareas (GSAs) defined by the General Fisheries Commission for the Mediterranean (GFCM), Northern Spain (GSA06) and Northern Alboran Sea (GSA01) sampled in July during the MEDiterranean International Acoustic Survey (MEDIAS). Our results suggest that in summer, a higher concentration and aggregation of fish exists in GSA01, with a density ten times greater than in GSA06. Possible life history changes can be inferred through the analysis of the biological parameters of Trachurus trachurus in the NW Mediterranean Sea. In both GSAs, the annual decline of the size at first maturity (L50) and condition factor (Kn) was prominent. Moreover, the population structure lacked adult modes that could guarantee a successful recuperation of future stocks. Nonetheless, fish inhabiting GSA01 seem to have a better adaptive response to the events responsible for these alterations. In comparison, GSA01 is under less fishing pressure and the upwelling occurring in this area contributes to a higher availability of food, in addition to reducing the increases in sea surface temperature due to climate change during the study period. [ABSTRACT FROM AUTHOR]

This study investigated the reproductive traits of the hermaphroditic four-finger threadfin, Eleutheronema tetradactylum, along the coasts of Thailand during January to December 2021. Fish samples were collected from Pattani Bay, Thailand to assess the sex ratio, gonadosomatic index (GSI), maturity stage and fecundity. Additional fish samples were also collected from other areas to evaluate the length and weight at first sex change (Ls50 and Ws50) and length at first maturity (Lm50). The overall sex ratio for male and female was 1:0.69 with male being predominant throughout the year. Threadfin fish spawn the whole year round with peaks during moderate rainy and heavy rainy seasons. Histological examination confirmed its protandrous hermaphrodite posing multiple spawning habits. The average fecundity was 1.85 × 105 ± 1.05 × 105 eggs and positively related with standard length, body weight, gonad weight, and egg diameter (p < 0.05). The Ls50 and Ws50 were 27.58 cm and 419.39 g, and 29.71 cm and 457.28 g, for fish from Pattani Bay and Samut Prakan province, respectively. The Lm50 of male from Pattani Bay and Samut Prakan province were 25.78 cm and 25.56 cm, respectively, which were larger than those from Satun and Nakhon Sri Thammarat provinces. The Lm50 of females from Pattani Bay was smaller than that from Samut Prakan province. This study provided fundamental information on the reproductive characteristics of E. tetradactylum, which can be implemented to support management of natural fish stock and aquaculture development. [ABSTRACT FROM AUTHOR]

The objective of the current study was to describe the female reproductive characteristics of populations of the non-indigenous shrimp Penaeus latisulcatus off the Egyptian Mediterranean coast. P. latisulcatus was sampled from the commercial catch of Boughaz El-Maadiyah's landing center off the Mediterranean coast between July 2020 and June 2021. This study focused on describing maturity stages, calculating the gonadosomatic index (GSI), determining the spawning season, and measuring the size at first maturity of female P. latisulcatus. The stages of ovarian development were divided into six stages; i.e., immature, early maturing, late maturing, nearly ripe, ripe, and spent. A prolonged spawning season was identified, extending from the summer season to autumn and showing a peak in August. The GSI followed the same pattern of ovarian maturation and confirmed the spawning season of P. latisulcatus. As revealed, 50% of female individuals attained maturity at a total length of 11.34 cm. Hence, this study provides fundamental and helpful information for understanding the reproductive dynamics of P. latisulcatus on the Egyptian Mediterranean coast as a new habitat for its propagation. This information also helps in providing the proper management of fisheries and conservation of this shrimp species, which can be useful for aquaculture processes as well. [ABSTRACT FROM AUTHOR]

Gill surface area (S) and respiration (R) in juvenile and adult crustaceans scale with their body weight (W) such that S ∝ R ∝ Wd, with d ranging mostly between 0.6 and 0.9, but always <1, as in other water-breathing ectotherms (WBE). The growth of adult crustaceans therefore approaches an asymptote, whether or not seasonal growth oscillations are explicitly considered in the model used to describe that growth (e.g. von Bertalanffy growth function). On the other hand, the variation in asymptotic size (L∞ or W∞) among crustaceans is primarily determined by water temperature, which impacts on the oxygen requirements of WBE. Through multiple examples, this and related aspects of the Gill-Oxygen Limitation Theory (GOLT), first developed for fishes and later extended to other WBE, are shown to also apply to the growth of a wide range of crustacean taxa. The GOLT also explains certain aspects of crustacean reproduction, such as the relationship between size at first maturity and maximum size, and, possibly, the feature that female crustaceans hold their eggs outside of their bodies instead of internally. [ABSTRACT FROM AUTHOR]

Global warming affects the phenology of the Earth's flora and fauna, notably by advancing the date at which many plants and animals tend to reproduce. We use fish, where this reproductive acceleration is well-documented, to present a simple approach based on sine curves to predict, in spring spawning fish, the minimum number of days (Δdmin) that spawning is advanced as the result of a given increase in water temperature (Δ°C). We show, via comparison with field estimates, that our simple model's robust predictions correspond to observed values of Δdmin/Δ°C, and discuss both the potential uses and the limitations of the model. [ABSTRACT FROM AUTHOR]

This present study provides an overview of the reproductive traits, including ovarian development, spawning season, size at maturity (Lm), and fecundity of Acentrogobius viridipunctatus - a high economic value fish in the Vietnamese Mekong Delta (VMD). A total of 432 females were collected using trawl nets from January to December 2020 at four sites, including Long Huu-Tra Vinh (LHTV), Trung Binh-Soc Trang (TBST), Dien Hai-Bac Lieu (DHBL), and Tan Thuan-Ca Mau (TTCM). The ovarian diameter was seen to increase from 2.09 (stage I) to 6.57 mm (stage V). Histological analysis showed that the goby was a multi-spawner due to the different oocyte stages found in stages IV and V of ovaries. It can release eggs all year-round due to the monthly appearance of ovarian stages IV and V during the study period, with the main peak in the 2-4 months of the wet season noted with the highest value of gonadosomatic index at that time. The Lm increased from 6.6 cm at TBST to 9.4 cm at TTCM. This species displayed relatively high fecundity, ranging from 5,481 to 130,683 eggs/female. The average fecundity of this fish was 27,698 ± 7,983 eggs/female at LHTV, 46,592 ± 7,264 eggs/female at TBST, 23,271 ± 4,985 eggs/female at DHBL, and 31,408 ± 2,515 eggs/female at TTCM. Egg diameter ranged from 0.45 ± 0.01 at DHBL to 0.50 ± 0.01 at TBST. For sustainable exploitation, local governments should ask the fishers to avoid catching fish during the main spawning period, and the fish length at first capture should be >Lm. [ABSTRACT FROM AUTHOR]

In this study, some reproductive parameters of the non-native silver crucian carp ( Carassius gibelio) in Seyhan Dam Lake (Southeastern Mediterrenean) were investigated. Samplings were conducted monthly through trammel nets between June 2013 and May 2014. From a total of 540 individuals investigated, 10 (1.85%) were males and 530 (98.15%) of them were females. The length at first maturation was detected as 16.8 cm TL. According to maturation stages of female gonads, ripe females were found to be present between February-July. Intense spawning periods was inspected in spring months of March, April, and May. The biggest egg diameter was found as 1.32 mm in March and the highest number of eggs was found as 347550. Silver crucian carp displayed a great reproductive output in Seyhan Dam Lake and the given reservoirs have been completely invaded. [ABSTRACT FROM AUTHOR]

This study investigates the ovarian development, spawning patterns, maturity size and fecundity of the goby Glossogobius giuris –a commercial fish in the Vietnamese Mekong Delta–based on the data analysis of 659 individuals. Specimens were caught using trawl nets from four sites representing freshwater (Cai Rang, Can Tho) to salinized regions in the dry season (Long Phu, Soc Trang), and brackish water regions (Hoa Binh, Bac Lieu and Dam Doi, Ca Mau) over the 12 months of 2020. Histological analysis showed that it was a multi-spawner as different stages of oocytes appeared in mature ovaries. The fish could spawn throughout the year, with a peak in April at the freshwater region and in September at salinized and brackish areas as mature ovaries appeared monthly during the studied period and gonadosomatic index displayed the highest value in April and in September, respectively. This goby's primary egg releasing time tended to be regulated by salinity changes over the four sampling sites. Likewise, size at first maturity of this species could be related to the salinity variation as this value was the longest in freshwater (6.14 ± 0.17) and the shortest in the salinization region (4.82 ± 0.66). Batch fecundity is measured at 5,118–100,003 eggs/female and related to fish length and weight (r2 > 0.76). Findings can be useful for the development of fish conservation strategies and artificial reproducing studies. [ABSTRACT FROM AUTHOR]

The present study delves into the reproductive characteristics of Metapenaeopsis andamanensis , a commercially significant deep-water shrimp collected from Sakthikulangara, off Kollam, India (8°56′60.78″ N/76°32′34.27″ E) during September 2019 to May 2022. Despite its economic importance, the reproductive traits of this species remain elusive. This research comprehensively examines macroscopic and microscopic features associated with gonadal maturity stages, including determination of size at first maturity (CL 50), gonadosomatic index, and fecundity of M. andamanensis. Male-to-female sex ratio was noted as 1:1.03 using chi-square analysis. The smallest mature individuals were observed at 12 mm and 16 mm carapace length for males and females, respectively. Macroscopic observation categorized females into five groups based on gonadal coloration, while microscopic examination identified seven stages using histological characteristics. Notably, the absence of cortical crypts in the periphery of oocyte cytoplasm, a characteristic feature of the genus Metapenaeopsis , was observed in this species. Males were classified into two categories based on macroscopic and microscopic observation. The gonadosomatic index ranged from 4.25 to 10.13 for mature female individuals, exhibiting a significant increase until stage IV. Continuous spawning was observed, with a peak in May and November. The size at first maturity for females and males was determined as carapace length (CL) 23.05 mm and 17.53 mm, respectively. The average absolute fecundity was calculated as 53,889 with an average relative fecundity of 9934 oocytes. This investigation contributes valuable insights into the reproductive traits of the deep-water penaeid shrimp M. andamanensi s, facilitating the development of effective management strategies for sustainable fisheries. • First study to address the relative and absolute fecundity of a Metapenaeopsis species. • M. andamanensis is a continuous spawner with peaks in May and November. • Gonado-somatic index increases rapidly until stage IV and then decreases in stage V. • Determining the size at maturity helps formulating mesh size regulations. [ABSTRACT FROM AUTHOR]

The peppery furrow shell Scrobicularia plana is a commercial valuable bivalve in the east Atlantic and Mediterranean Sea. To ensure the sustainability of this resource and implement efficient management strategies, it is essential to understand the life history traits of the species, such as growth, reproduction, and size at first maturity. These features were investigated in the southern range of the species' European distribution, specifically in Ria de Aveiro (Portugal), and compared to other geographical areas. At Ria de Aveiro S. plana spawns from June to October, with a peak in August/September, aligning with the typical reproductive pattern of mid latitude European populations. The condition index is lowest in March and highest in May just before spawning. Sexual maturity (L 50 = 27 mm SL) is attained at approximately 1 year of age, enabling offspring to reproduce in the subsequent spawning season. In this study, the overall sex ratio did not differ significantly from 1:1. Hermaphroditism (ovotestis) was detected in one specimen, representing 0.3% of the total examined males. Shell rings are formed annually during growth cessation in fall/winter and become conspicuous when growth resumes in March. The growth equation parameters, estimated from surface shell ring analysis and internal shell microgrowth bands, were: Lt = 58.1[1 - e−0.46(t −0.09)]; Lt = 54.7[1 - e−0.53(t −0.30)], respectively. Values for K and L ∞ are among the highest recorded for the species, highlighting the growth performance of S. plana in the Ria de Aveiro and its potential for commercial exploitation. An analysis of morphometric relationships between shell length, height, and width was performed to optimize the harvesting process of S. plana. Management measures are proposed for the fishery of S. plana in Ria de Aveiro, based on the species' biological traits. [Display omitted] • Reproductive biology of Scrobicularia plana is described. • Condition index exhibited a seasonal pattern linked to the reproductive cycle. • Fast growth and rapid maturity allow first-year reproduction. • A minimum conservation reference size of 27 mm SL can enhance sustainable exploitation. • A closed fishing season between August and November should be enforced. [ABSTRACT FROM AUTHOR]

Recent estimates of the size at first maturity (L 50) of Sardinella brasiliensis showed contradictory results with a decreasing in the fish stock biomass encompassed by increasing values of L 50. The methodological approach used hereby allowed to separate sardines classified in the virginal maturity stage from those categorized in the recovery stage, and ready for one next spawning event. This study evaluated the hypothesis of the existence of separated stocks experiencing distinct environmental conditions and fishing pressures which may have altered L 50 estimates using a robust dataset based on biological samples collected along the entire species distribution area in the southeast-south Brazilian coast [Rio de Janeiro (RJ), São Paulo (SP), Paraná (PR), Santa Catarina (SC) and Rio Grande do Sul (RS)] between 2000 and 2018. A reclassification of the gonadal maturity stages provided a more realistic estimate of L 50. Combining biological, reproductive, fishing data and the mean temperature of the catch (MTC), the leave-one-out classification correctly re-assigned individuals with an overall accuracy of 85% [100% (RJ), 45% (SP), 99% (PR), 99% (SC) and 82% (RS)]. The connectivity between the local populations of S. brasiliensis off RJ (23°S) and the southern populations is limited, contrasting to spatial structured semi-discrete population-units found between SP and RS (24°S-30°S). The northern extreme population-unit (RJ, 22°S-23°S) showed an expressive reduction of L 50 , and a negative correlation was detected between the increasing MTC values and the abundance of early maturing individuals and recruits of the species. Stock specific L 50 estimates seemed to act as indicators of long term environmental fluctuations. • A long-term assessment of S. brasiliensis was conducted using a novel methodology • The study distinguishes 2 population-units: northern (22-23°S) and southern (24-30°S) • The northern population shown a notable reduction of the size at first maturity (L 50) • L 50 estimates correlated with increased mean temperature of the catch • Stock-specific L 50 may be used as indicator of long-term environmental fluctuations [ABSTRACT FROM AUTHOR]

Here we report findings regarding the reproductive biology of swordfish Xiphias gladius in Corsican waters in the north-western Mediterranean Sea. We sampled 558 swordfish (72–216 cm; lower jaw to fork length, LJFL) caught from June to September in 2019 and 2020 off Corsica's western and eastern coasts. We assessed swordfish reproductive activity using macroscopic gonad characteristics, trends of gonadal indexes for both sexes, and histological investigation of oocyte developmental stages. Size at first maturity (L 50) was estimated at 139.2 ± 2.7 (95% CI) cm LJFL for females using histological techniques and 117 ± 1.7 cm (LJFL) for males using macroscopic criteria, corresponding to 3–4 and 2–3 year old-fish, respectively. Spawning occurred mainly from June to July, with a peak in July, characterized by a high gonadal index and histological and macroscopic evidence of reproductive activity. X. gladius spawning period is of relatively short duration, closely linked to SST, during which the females lay successive batches of eggs at a non-evaluated frequency. Batch fecundity (BF) and relative fecundity (RF) were estimated from five gravid females (135–209 cm LJFL) with unovulated, hydrated oocytes. BF was exponentially related to fish length with a mean BF of 1.94 ± 1.33 (mean ± SD) million hydrated oocytes in females. RF ranged from 22.29 to 37.24 (29.05 ± 5.97; mean ± SD) hydrated oocytes per gram of body weight. Our results improve knowledge regarding the sexual maturity, reproductive period, and spawning areas of swordfish in Corsican waters. These data are essential for the spatiotemporal management of Mediterranean swordfish stocks. We also provide an overview of the available information related to the reproductive biology and dynamics of Mediterranean swordfish and demonstrate the ubiquitous presence of swordfish spawning grounds throughout the Mediterranean Sea. • Female swordfish L 50 (histological estimate) is 139.2 cm LJFL, and male L 50 (macroscopic estimate) is 117 cm LJFL. • In Corsican waters, swordfish spawn mainly in June and July. • Swordfish batch fecundity ranges from 0.68 to 4.13 × 106. • Overview of available information on the reproductive biology of swordfish in Mediterranean Sea. [ABSTRACT FROM AUTHOR]