scholarly journals First observations of hermaphroditism in the patellid limpet Patella piperata Gould, 1846

2019 ◽  
Vol 99 (7) ◽  
pp. 1615-1620
Author(s):  
Ricardo Sousa ◽  
Paulo Henriques ◽  
Joana Vasconcelos ◽  
Graça Faria ◽  
Rodrigo Riera ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Direct Effect ◽  
Shell Length ◽  
Histological Analysis ◽  
Size Classes ◽  
Sequential Hermaphroditism ◽  
North Eastern ◽  
Intermediate Size ◽  
Transitional Forms ◽  
Management And Conservation

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.

scholarly journals Seasonal variations in the population biology of Salmostoma bacaila (Cyprinidae) from a tributary of the Payra River, Bangladesh

2019 ◽  
pp. 113-119
Author(s):  
Ahamed Ahamed ◽  
Faruque Ahmed Zoarder ◽  
Jun Ohtomi
Keyword(s):  
Sex Ratio ◽  
Seasonal Variations ◽  
Population Biology ◽  
Sexual Maturity ◽  
Condition Factor ◽  
Gonadosomatic Index ◽  
Spawning Season ◽  
Frequency Distributions ◽  
Size At Sexual Maturity ◽  
Management And Conservation

Some biological parameters of Salmostoma bacaila – including sex ratio, length-frequency distributions (LFDs), size at sexual maturity, spawning season, length-weight relationships (LWRs) and condition factor – were studied. Samples were collected seasonally during June 2017 to May 2018 from a tributary of the Payra River. The overall sex ratio was significantly different from the expected value of 1:1 (p < 0.001), in favour of male specimens. Females were significantly larger than males. Size at sexual maturity was estimated at 7.6~7.7 cm total length. Seasonal variations in the gonadosomatic index (GSI) indicate that the main spawning season is from spring to summer. The LWRs showed negative allometric growth in both sexes, but with clear seasonal variation. Fulton’s condition factor varied in both sexes and was attributed to variations in GSI with maturity. The fin¬dings of this study will be helpful for management and conservation of S. bacaila populations.

Variations in eastern oyster (Crassostrea virginica) sex-ratios from three Virginia estuaries: protandry, growth and demographics

2012 ◽  
Vol 93 (2) ◽  
pp. 519-531 ◽  
Author(s):  
Juliana M. Harding ◽  
Eric N. Powell ◽  
Roger Mann ◽  
Melissa J. Southworth
Keyword(s):  
Sex Ratio ◽  
Shell Length ◽  
Sex Ratios ◽  
Eastern Oyster ◽  
Reproductive Capacity ◽  
Older Individuals ◽  
Population Demographics ◽  
Disease Mortality ◽  
Predominantly Female ◽  
Male To Female

Oyster population reproductive capacity and dynamics are controlled at the most basic level by the observed sex-ratios. Since oysters are sequential, protandric hermaphrodites the population sex-ratio is related to the demographics (shell length, age, and biomass). Oysters were collected from June through to August 2008 at twelve bars in the James, Rappahannock and Great Wicomico Rivers, Virginia, USA. Bars were aggregated into five groups on the basis of similar age–length relationships. Sex-ratios (fraction female), age–length, and biomass–length relationships were determined for each group. The fraction female increased within increasing shell length, age, and biomass at all sites. Simultaneous hermaphrodites were rarely observed. Group specific differences in shell length (SL, mm) and age (yr) for the timing of the protandric shift were observed with the earliest shift from male to female occurring at ~60 mm SL and ~1.6 yr. The proportion of females observed in the larger or older individuals was at least 70–80%. Sex-ratios from summer 2008 were used to develop sex–length, sex–age, and sex–biomass keys that were applied to autumn-survey data from 2006, 2007, 2008 and 2009. In these years, sex-ratios by shell length and age were strongly biased towards males while the sex-ratio by biomass was strongly biased towards females. Disease mortality compounds natural and fishing mortality resulting in age/size specific cropping yielding truncated population demographics and an earlier protandric shift in populations on the extremes of the range examined. Regardless of location, market (>76 mm SL) oysters are predominantly female.

Caligus elongatus (Copepoda: Caligoida) from Atlantic salmon (Salmo salar) cultured in marine waters of the Lower Bay of Fundy

1989 ◽  
Vol 67 (4) ◽  
pp. 1080-1082 ◽  
Author(s):  
W. E. Hogans ◽  
Deborah J. Trudeau
Keyword(s):  
Sex Ratio ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Gravid Female ◽  
Market Size ◽  
Bay Of Fundy ◽  
Marine Waters ◽  
Size Classes ◽  
Atlantic Salmon Salmo Salar ◽  
Passamaquoddy Bay

The occurrence of Caligus elongatus on Atlantic salmon (Salmo salar) cultured in marine waters in the Passamaquoddy Bay region of the lower Bay of Fundy is reported. Two size classes of cultured salmon (smolts and market size) were examined. Prevalence of C. elongatus was 54.5% on market fish and 54.7% on smolts. Intensities of infection for market fish and smolts were recorded as 2.41 and 2.58, respectively. Overall sex ratio of adult C. elongatus on infected salmon was 1:1.4 females to males; mean number of eggs per gravid female C. elongatus was 169.

Reproductive biology of the land crab Cardisoma guanhumi (Decapoda: Gecarcinidae) in north-eastern Brazil

2012 ◽  
Vol 93 (3) ◽  
pp. 761-768 ◽  
Author(s):  
Renata Akemi Shinozaki-Mendes ◽  
José Roberto Feitosa Silva ◽  
Jones Santander-Neto ◽  
Fábio Hissa Vieira Hazin
Keyword(s):  
Sexual Maturity ◽  
Histological Analysis ◽  
Carapace Width ◽  
Gonadal Maturation ◽  
Land Crab ◽  
Eastern Brazil ◽  
North Eastern ◽  
Cardisoma Guanhumi ◽  
Maturation Stages ◽  
First Maturity

The reproductive cycle of Cardisoma guanhumi was described from the analysis of seasonal variation of the gonadal maturation stages. The first maturity for both sexes was determined based on three different tests: inflexion point on the curve; relevant character (morphometry); and histological analysis (physiology). In addition, some aspects of sexual dimorphism for the population were studied. A total of 353 individuals caught in north-eastern Brazil between December 2006 and November 2007 were analysed. The sex-ratio was statistically equal (P ≥ 0.05) and the carapace width (CW) of the females ranged from 4.34 to 8.56 cm and of the males from 2.84 to 9.22 cm. Mature females with fully developed gonads begin to appear in the dry season (August) and ovigerous females occurred from November to February, suggesting that spawning occurs mainly during the rainy season. The CW of first sexual maturity for females ranged from 5.87 cm to 6.70 cm and males from 6.22 cm to 7.20 cm. The highest percentage of individuals caught were juveniles, indicating the need for a targeted effort to preserve the species.

scholarly journals Reproduction of Megapitaria squalida (Bivalvia: Veneridae) in the Southeast Gulf of California, Mexico

2017 ◽  
Vol 65 (3) ◽  
pp. 881 ◽  
Author(s):  
Ernesto Álvarez-Dagnino ◽  
Apolinar Santamaría-Miranda ◽  
Manuel García-Ulloa ◽  
Andrés Martín Góngora-Gómez
Keyword(s):  
Reproductive Cycle ◽  
Gulf Of California ◽  
Histological Analysis ◽  
Conservation Strategies ◽  
Oocyte Size ◽  
Spawning Activity ◽  
Two Peaks ◽  
Management And Conservation ◽  
Clam Population ◽  
Resting Period

Bivalves reproductive cycle varies according to the particular environmental conditions where they are found, and these reproductive details represent basic information for their capture, management and conservation strategies. With this objective, the reproductive cycle of the clam Megapitaria squalida, inhabiting the Southeast of the Gulf of California (Altata Bay, Sinaloa, Mexico), was studied using histology and changes in the number and size of oocytes, from June 2013 to June 2014. Histological analysis of the gonads showed spawning activity throughout the year, with two peaks. The first was registered in October and it was accompanied by the highest decrease of weight; the second was in February with the highest percentage of spawning population; besides, a resting period was observed in December. The sex-ratio (female:male) of the clam population was 1.08:1 (χ2 = 5.72, d.f. = 1, P < 0.05). Mean oocyte size and number were different (P < 0.05) among all sampling months and fluctuated from 34.6 ± 5.8 µm in June 2014, to 41.9 ± 6.8 µm in February 2014, and from 443.8 ± 424.5 in February 2014, to 1 214.4 ± 267.6 counted in April, respectively. With these results we suggest a protection season from October to November, when the most intense release of gametes occur in this population.

The biology and functional morphology of the predatory septibranch Cardiomya costellata (Deshayes, 1833) (Bivalvia: Anomalodesmata: Cuspidariidae) from the Acores: survival at the edge

2015 ◽  
Vol 96 (6) ◽  
pp. 1347-1361 ◽  
Author(s):  
Brian Morton
Keyword(s):  
Functional Morphology ◽  
Shell Length ◽  
Reproductive Strategy ◽  
Anatomical Study ◽  
Hydrodynamic Forces ◽  
Simultaneous Hermaphrodite ◽  
Post Mortem ◽  
Potential Prey ◽  
North Eastern ◽  
Inhalant Siphon

This is the first comprehensive anatomical study of a representative of the septibranch Cuspidariidae. Particular interest in Cardiomya costellata is related to the fact that only two species of such predatory septibranchs have been recorded from the remote Açorean Archipelago and, here, individuals of both taxa are half the shell length of conspecifics throughout the species’ North-eastern Atlantic range. The shell of C. costellata is thin, fragile and rostrate. This latter attribute allows the inhalant siphon (as in other cuspidarioids) to be extended towards potential prey to effect their capture. How this extension is effected has been described but, herein, the hydrodynamic forces needed to achieve this are put into a firmer anatomical context. Uniquely amongst the Anomalesmata, cuspidarioids have, previously, been regarded as dioecious. This is not the case for C. costellata, which is a protandric consecutive hermaphrodite. The gonads and reproductive strategy of this species are compared with those of the spheniopsid Grippina coronata that is representative of a second cuspidarioid family of deeper water predators and which is a simultaneous hermaphrodite brooding self-fertilized embryos in the gonadial follicles with their release being post mortem. Some evidence suggests that in the Açores, the possible crustacean prey of C. costellata are also smaller than their mainland conspecifics, which, when viewed in the overall context of the predator's biology and anatomy, might explain its poor success in the oligotrophic waters of these mid-Atlantic islands.

Direct Observation of Sex Change in the Patellacean Limpet Lottia Gigantea

1982 ◽  
Vol 62 (3) ◽  
pp. 737-738 ◽  
Author(s):  
William G. Wright ◽  
David R. Lindberg
Keyword(s):  
Sexual Dimorphism ◽  
Differential Growth ◽  
External Fertilization ◽  
Size Classes ◽  
Direct Observations ◽  
Protandric Hermaphroditism ◽  
Intermediate Size ◽  
Lottia Gigantea ◽  
Male To Female ◽  
Simultaneous Hermaphrodites

Protandric hermaphroditism, the sequential change from male to female, has been reported in several superfamilies of prosobranch gastropods including the Fissurellacea, Patellacea, Calyptraeacea, and Eulimacea (Webber, 1977). It is most common in members of the Calyptraeacea and the Patellacea. In the Calyptraeacea changes in sex are readily followed by observing copulative structures (Coe, 1944). Because patellacean limpets are predominantly broadcast spawners with external fertilization, external characters that can be used to determine the sex of individuals are rare. Hence, previous to this report the occurrence of protandry in most patellacean limpets has been based primarily on sexual dimorphism in size; the smaller size classes being made up of male individuals and the larger size classes of female individuals (Willcox, 1898; Orton, 1920, 1928; Orton, Southward & Dodd, 1956; Dodd, 1956; Branch, 1974). However, given this type of data it is often difficult to assess whether the observed sexual dimorphism is indicative of protandry or merely a result of differential growth and/or survival. The presence of simultaneous hermaphrodites in the intermediate size classes, as evidence of protandry is of limited value because simultaneous hermaphrodites occur sporadically in patellaceans that do not show a sexual dimorphism in size (Dodd, 1956; Branch, 1974). The only unambiguous way of proving the existance of protandry in patellacean limpets is the direct monitoring of gonadal changes in individuals through time. We report here the first direct observations of protandric hermaphroditism in a patellacean limpet.Lottia gigantea Sowerby, 1834 is a large (100 + mm), territorial, intertidal limpet that ranges from northern California to central Baja California, Mexico (Stimson, 1970).

On the reproduction of the Mediterranean keystone limpet Patella rustica: histological overview

2014 ◽  
Vol 94 (8) ◽  
pp. 1651-1660 ◽  
Author(s):  
Ivana Prusina ◽  
Daria Ezgeta-Balić ◽  
Stijepo Ljubimir ◽  
Tatjana Dobroslavić ◽  
Branko Glamuzina
Keyword(s):  
Reproductive Cycle ◽  
Shell Length ◽  
Histological Analysis ◽  
Developmental Stages ◽  
Gonad Development ◽  
Gonad Index ◽  
Keystone Species ◽  
Males And Females ◽  
Sexually Mature ◽  
High Shore

The reproductive cycle of the high shore limpet Patella rustica is described based on histological analysis as the primary method of staging gonad development. Sex-ratios, shell length at sexual maturity, gonad developmental stages, mean gonad index and oocyte size were investigated. Males and females were found to differ in size distribution, with females becoming more prevalent from ~28 mm onwards. The estimated shell length at which 50% of males were sexually mature was 13.1 mm. Patella rustica has only one reproductive cycle per year with a spawning peak between November and December for both sexes, and gonad redevelopment from January. First data on the size–frequency analysis of oocytes for this species are also presented, concurring with the qualitative analysis of the gonad developmental stages. This study presents updated information on the reproductive cycle of this keystone species and provides the first account of the reproductive biology of P. rustica in the Adriatic Sea.

scholarly journals Biological aspects of spotted seerfish Scomberomorus guttatus (Bloch & Schneider, 1801) (Scombridae) from north-eastern Arabian Sea

2018 ◽  
Vol 65 ◽  
Author(s):  
C. Anulekshmi ◽  
J. D. Sarang ◽  
S. D. Kamble ◽  
K. V. Akhilesh ◽  
V. D. Deshmukh ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Arabian Sea ◽  
Biological Information ◽  
Relative Fecundity ◽  
Northern Arabian Sea ◽  
North Eastern ◽  
Eastern Arabian Sea ◽  
Biological Aspects ◽  
Gravid Females ◽  
First Maturity

Spotted seerfish <em>Scomberomorus guttatus</em> (Bloch &amp; Schneider, 1801) is one of the highly priced table fishes in India, which contributed 4.7% of all India scombrid fishery with 17,684 t landed in 2014. Its fishery is dominant in the Arabian Sea and northern Arabian Sea contributed 62% to India’s spotted seerfish fishery. Biological information on <em>S. guttatus</em> is scarce and the same was studied during the period 2010-2014 from Maharashtra coast, north-eastern Arabian Sea. A total of 930 specimens (185-550 mm FL) collected from commercial landings were used for the study. Length-weight relation of pooled sexes was estimated as log (W) = -3.1988+2.66074 log (L) (r2 = 0.93). Fishery was dominated by males with the sex ratio of 0.76:1. Relative fecundity ranged from 105-343 eggs g-1 of bodyweight. The length at first maturity (Lm) was estimated to be 410 mm TL for females. Mature and gravid females were dominant in May and August-November. Dietary studies (% IRI) showed dominance of <em>Acetes</em> spp.

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