Insights on the seasonal variations of reproductive features in the Eastern Atlantic Bluefin Tuna

Carnevali, Oliana; Maradonna, Francesca; Sagrati, Andrea; Candelma, Michela; Lombardo, Francesco; Pignalosa, Paolo; Bonfanti, Erica; Nocillado, Josephine; Palma, Peter; Gioacchini, Giorgia; Elizur, Abigail

doi:10.1016/j.ygcen.2019.113216

Cited by 9 publications

(6 citation statements)

References 65 publications

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“…Lower levels of ccnb1 in the Active-old group might reflect an ongoing translation of the pool of mRNA stored throughout the oogenesis in preparation for the next phase of meiosis resumption via the activation of the M-phase-promoting factor [ 80 ]. On the other side, the vtgR expression in our study reflected the findings of [ 51 ] in the Atlantic bluefin tuna, with higher levels in unyolked oocytes at an early stage of ovarian development well before the spawning season, indicative of temporally uncoupled expression and translation as well as an early preparation for the next spawning season [ 75 ]. Interestingly, cpeb2 exhibited increased expression levels in group Active-old respect to Active-young suggesting a role during the final steps of oocyte maturation to regulate polyadenylation and translation of maternal mRNA, as previously demonstrated for members of the CPEB family [ 81 , 82 ].…”

Section: Discussionsupporting

confidence: 79%

“…Indeed, this observation is also supported by different spatial-temporal patterns of gonad maturation across the Mediterranean Sea, which reflect a more complex demographic substructure and reproductive dynamics [ 71 ]. The presence of POFs and maturing oocytes undoubtedly highlights that the bluefin tuna can spawn also in tuna traps, a well-documented phenomenon in transport cages and farms off the eastern coasts of Spain [ 72 , 73 , 74 ] but irregularly observed in tuna traps in the area investigated [ 59 , 60 , 75 ]. Future efforts with a focus also on abiotic factors (e.g., water temperature) or surface plankton surveys would be suggested to clarify if it represents a sporadic or regular event and eventually define its relevance in the area.…”

Section: Discussionmentioning

confidence: 99%

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A Comparison of Reproductive Performances in Young and Old Females: A Case Study on the Atlantic Bluefin Tuna in the Mediterranean Sea

Marisaldi

Iorillo

Basili

et al. 2021

Animals

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In the Mediterranean Sea, a demographic substructure of the Atlantic bluefin tuna Thunnus thynnus has emerged over the last decade, with old and young individuals exhibiting different horizontal movements and spatial–temporal patterns of gonad maturation. In the present study, histology and molecular reproductive markers were integrated with the gonad-specific mir-202 gene expression and ovarian localization to provide a comprehensive picture of the reproductive performances in young and old females and investigate the role played by the mir-202 during gonadal maturation. During the reproductive period, old females (>100 kg; 194.6 ± 33.9 cm straight fork length; 11.3 ± 2.7 years old) were found to have greater reproductive performances than younger females (<80 kg; 139.3 ± 18.8 cm straight fork length; 8.4 ± 1.1 years old) according to gene expression results, suggesting a prolonged spawning season, earlier arrival on spawning grounds and/or better condition in older females. The mir-202-5p showed no global changes; it was abundantly expressed in granulosa cells and faintly present in the ooplasm. On the other hand, the mir-202-3p expression profile reflected levels of oocyte maturation molecular markers (star, lhr) and both histological and molecular (casp3) levels of follicular atresia. Overall, old females exhibited greater reproductive performances than younger females, likely reflecting different reproductive dynamics linked to the physical condition, habitat usage and migratory behaviour. These results highlight the importance of preserving large and old females in the context of fishery management. Finally, the mir-202 appears to be a good candidate to regulate the reproductive output of this species in an autocrine/paracrine manner through either stage- or age-dependent processes.

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Section: Discussionsupporting

confidence: 79%

Section: Discussionmentioning

confidence: 99%

A Comparison of Reproductive Performances in Young and Old Females: A Case Study on the Atlantic Bluefin Tuna in the Mediterranean Sea

Marisaldi

Iorillo

Basili

et al. 2021

Animals

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“…Carnevali et al . (2019), however, observed early atretic follicles to persist until October–November in bluefin tuna maintained in a commercial farm off Malta. The occurrence of early atretic stages of yolked follicles (α and β atresia) is often used in fish maturity classifications and characterization of temporal reproductive patterns ( e.g ., Lowerre‐Barbieri et al ., 2011; Schaefer, 1998, 2001).…”

Section: Discussionmentioning

confidence: 98%

An autofluorescence‐based survey of late follicular atresia in ovaries of a teleost fish (Thunnus thynnus)

Medina

Magro

Paullada-Salmerón

et al. 2021

Journal of Fish Biology

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In this study, the authors examined late atretic follicles in the ovaries of Atlantic bluefin tuna, Thunnus thynnus (Linnaeus 1758), at different times of the year using transmitted light and epifluorescence microscopy. Atresia (degeneration and resorption of developing ovarian follicles) is a natural process involved in fecundity downregulation in teleosts and is substantially enhanced in stressful conditions. Early (α and β) atretic stages of yolked oocytes have a relatively short duration in seasonally reproducing species, whereas later (γ and δ) atretic follicles (LAF) persist for longer time in the ovary, serving as a sign of previous vitellogenic activity. LAF can thus be used as reliable markers of maturity during non-reproductive periods. Lipofuscin granules accumulate in the cytoplasm of LAF cells as a result of lysosomal digestion of oocyte components. Taking advantage of the well-known autofluorescent properties of lipofuscins, LAF may be identified in unstained histological sections under fluorescence microscopy using appropriate excitation and emission wavelengths. The authors explore in this study the applicability of fluorescence microscopy to provide a fast and effective method to assess late atresia in fishes. This method may be particularly useful to determine sexual maturity in individuals sampled long after the spawning season, where LAF are difficult to detect in standard histological sections. Furthermore, LAF autofluorescence provides a rapid way to quantify late atresia in fishes using image analysis.

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“…7 In fish, it is possible to monitor the reproductive cycle and seminal quality 8 through the monthly distribution of the gonadosomatic index values. [9][10][11] Among reproductive aspects, knowledge of quantitative and qualitative seminal parameters is relevant for their implications in better or more efficient chances of fertility and fertilization. 12 In this context, low-cost and non-invasive tools, such as GSI, can help determine and monitor the reproductive cycle and seminal quality.…”

Section: Introductionmentioning

confidence: 99%

Seasonal variations in gonadosomatic index and seminal quality of squirrel monkeys (Saimiri collinsi)

Sampaio

Leão

Sousa

et al. 2022

J of Medical Primatology

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Background We hypothesized that seasonal variations in testicular biometry in Saimiri collinsi are influenced by body mass and that testicular enlargement is related to improved seminal quality. Therefore, the gonadosomatic index (GSI) can be a tool to determine reproductive seasons and the predictors of seminal quality. Methods Body mass, testicular biometry, and semen samples were obtained from eight adult males monthly and evaluated. Results In the non‐fattening/non‐reproductive season, the body mass and GSI decreased and increased, respectively, in the fattening. A positive correlation was only observed between the GSI and seminal volume. During fattening, high seminal volume and normal morphology were observed, but sperm concentrations were low. Conclusion The GSI cannot be used as a predictor of seminal quality, but selective pressure to improve seminal quality may increase the chances of fertilization at fattening. The GSI provides new information on seasonality and can be used to identify reproductive seasons in squirrel monkeys.

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Insights on the seasonal variations of reproductive features in the Eastern Atlantic Bluefin Tuna

Cited by 9 publications

References 65 publications

A Comparison of Reproductive Performances in Young and Old Females: A Case Study on the Atlantic Bluefin Tuna in the Mediterranean Sea

A Comparison of Reproductive Performances in Young and Old Females: A Case Study on the Atlantic Bluefin Tuna in the Mediterranean Sea

An autofluorescence‐based survey of late follicular atresia in ovaries of a teleost fish (Thunnus thynnus)

Seasonal variations in gonadosomatic index and seminal quality of squirrel monkeys (Saimiri collinsi)

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