2019 ◽  
Vol 99 (7) ◽  
pp. 1615-1620
Author(s):  
Ricardo Sousa ◽  
Paulo Henriques ◽  
Joana Vasconcelos ◽  
Graça Faria ◽  
Rodrigo Riera ◽  
...  

AbstractHermaphroditism is thought to be an advantageous strategy common in marine molluscs that exhibit simultaneous, sequential or alternating hermaphroditism. Several species of patellid limpets have previously been shown to be protandrous hermaphrodites. The present study aimed to confirm whether this phenomenon occurs in Patella piperata. Transitional forms of simultaneous protandrous hermaphroditism were found in intermediate size classes of P. piperata, in Madeira (North-eastern Atlantic). Sequential hermaphroditism was confirmed after histological analysis. The overall sex-ratio was biased towards females but approached similar proportions in the larger size classes. Analysis of size at sex change showed that at a shell length of 36 mm 50% of the population probably have changed sex. The results reported confirm the occurrence of sequential hermaphroditism. These findings are of utmost importance to the understanding of the reproductive biology of this species with direct effect on management and conservation of this traditionally harvested limpet.


2014 ◽  
Vol 58 (4) ◽  
pp. 314-318 ◽  
Author(s):  
Jung Sick Lee ◽  
Jung Jun Park ◽  
Yun Kyung Shin ◽  
Hyejin Kim ◽  
Mi Ae Jeon

2016 ◽  
Vol 65 (1) ◽  
pp. 181 ◽  
Author(s):  
Juan Pablo Gassman ◽  
Héctor López-Rojas ◽  
Dana Padrón

Snooks C. undecimalis and C. ensiferus are important fishery resources in their distribution area. In Venezuela they are caught by artisanal fisheries along the entire coast. However, studies on their biology that would help establish fishing regulations are scarce. To study reproduction aspects of these species, we analyzed 1 325 individuals of C. undecimalis and 2 025 of C. ensiferus caught by artisanal fishing in the Laguna de Tacarigua in Northern Venezuela, from July 2009 to September 2010. Total length, total weight, sex and stage of gonadal development were recorded. The sex ratio varied throughout the year: there was a significant difference in favor of C. undecimalis males (1.5:1), and C. ensiferus females (1:3.3). Differences were also evident in the sexual proportion at each size group. For both species, males dominated in the lower size ranges while females dominated in the larger size ranges. These results suggested sequential hermaphroditism (protrandry) in both species. Size at sexual maturity (Lm50) for C. undecimalis was ♀= 73.6 and ♂= 59.3 cm, and ♀= 26 and ♂= 21.5 cm for C. ensiferus. C. ensiferus reproduced throughout the year with two periods of higher intensity (August to September and February to April). Although we found very few mature individuals for C. undecimalis, February showed an important reproduction peak. Growth differences were found between males and females of C. undecimalis: positive allometry for females (P= 0.0022*L3.353) and negative allometry for males (P= 0.0108*L2.945). Both males and females of C. ensiferus showed a positive allometric relationship (P= 0.0049*L3.235). Lack of fishing regulations and controls, evidenced in this study by significant volumes of immature individuals in the catches, and the particular reproductive biology of these species, strongly indicates the need to establish regulations to ensure their responsible use. We recommend establishing a closed season during the first quarter of the year and minimum catch sizes for both species.


BioEssays ◽  
2020 ◽  
Vol 42 (10) ◽  
pp. 2000050
Author(s):  
Barbora Straková ◽  
Michail Rovatsos ◽  
Lukáš Kubička ◽  
Lukáš Kratochvíl

2009 ◽  
Vol 173 (3) ◽  
pp. 327-336 ◽  
Author(s):  
Erem Kazancıoğlu ◽  
Suzanne H. Alonzo

2006 ◽  
Vol 60 (4) ◽  
pp. 541-547 ◽  
Author(s):  
David R. Bybee ◽  
Julie H. Bailey-Brock ◽  
Clyde S. Tamaru

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sara M. Stieb ◽  
Fanny de Busserolles ◽  
Karen L. Carleton ◽  
Fabio Cortesi ◽  
Wen-Sung Chung ◽  
...  

Abstract Vision plays a major role in the life of most teleosts, and is assumingly well adapted to each species ecology and behaviour. Using a multidisciplinary approach, we scrutinised several aspects of the visual system and ecology of the Great Barrier Reef anemonefish, Amphiprion akindynos, including its orange with white patterning, retinal anatomy and molecular biology, its symbiosis with anemones and sequential hermaphroditism. Amphiprion akindynos possesses spectrally distinct visual pigments and opsins: one rod opsin, RH1 (498 nm), and five cone opsins, SWS1 (370 nm), SWS2B (408 nm), RH2B (498 nm), RH2A (520 nm), and LWS (554 nm). Cones were arranged in a regular mosaic with each single cone surrounded by four double cones. Double cones mainly expressed RH2B (53%) in one member and RH2A (46%) in the other, matching the prevailing light. Single cones expressed SWS1 (89%), which may serve to detect zooplankton, conspecifics and the host anemone. Moreover, a segregated small fraction of single cones coexpressed SWS1 with SWS2B (11%). This novel visual specialisation falls within the region of highest acuity and is suggested to increase the chromatic contrast of Amphiprion akindynos colour patterns, which might improve detection of conspecifics.


2021 ◽  
Vol 11 ◽  
Author(s):  
Qing-Ping Xie ◽  
Bing-Bing Li ◽  
Wei Zhan ◽  
Feng Liu ◽  
Peng Tan ◽  
...  

Animal taxa show remarkable variability in sexual reproduction, where separate sexes, or gonochorism, is thought to have evolved from hermaphroditism for most cases. Hermaphroditism accounts for 5% in animals, and sequential hermaphroditism has been found in teleost. In this study, we characterized a novel form of the transient hermaphroditic stage in little yellow croaker (Larimichthys polyactis) during early gonadal development. The ovary and testis were indistinguishable from 7 to 40 days post-hatching (dph). Morphological and histological examinations revealed an intersex stage of male gonads between 43 and 80 dph, which consist of germ cells, somatic cells, efferent duct, and early primary oocytes (EPOs). These EPOs in testis degenerate completely by 90 dph through apoptosis yet can be rescued by exogenous 17-β-estradiol. Male germ cells enter the mitotic flourishing stage before meiosis is initiated at 180 dph, and they undergo normal spermatogenesis to produce functional sperms. This transient hermaphroditic stage is male-specific, and the ovary development appears to be normal in females. This developmental pattern is not found in the sister species Larimichthys crocea or any other closely related species. Further examinations of serum hormone levels indicate that the absence of 11-ketotestosterone and elevated levels of 17-β-estradiol delineate the male intersex gonad stage, providing mechanistic insights on this unique phenomenon. Our research is the first report on male-specific transient hermaphroditism and will advance the current understanding of fish reproductive biology. This unique gonadal development pattern can serve as a useful model for studying the evolutionary relationship between hermaphroditism and gonochorism, as well as teleost sex determination and differentiation strategies.


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