Morphometry and Maturity of Paired Tanner Crabs, Chionoecetes bairdi, from Shallow- and Deepwater Environments

1993 ◽  
Vol 50 (7) ◽  
pp. 1504-1516 ◽  
Author(s):  
Bradley G. Stevens ◽  
William E. Donaldson ◽  
Jan. A. Haaga ◽  
J. Eric Munk
Keyword(s):  
Body Size ◽  
Shallow Water ◽  
Size Range ◽  
Carapace Width ◽  
Wild Populations ◽  
Male And Female ◽  
Female Partners ◽  
Paired Male ◽  
Chionoecetes Bairdi ◽  
Mating Aggregation

Paired male and female Tanner crabs, Chionoecetes bairdi, in a premating embrace were collected from shallow-(< 13 m) and deepwater (> 150 m) benthic environments by scuba and submersible, respectively. Pubescent females were restricted to shallow water; males grasping them were significantly smaller than those grasping oldshell multiparous females with eyed embryos in a large, deepwater mating aggregation. Males appeared to select for large sizes among pubescent females, but not among multiparous females, which were limited in size range. Grasping males were 82.6–166.2 mm carapace width (CW) [Formula: see text] and represented at least three different width frequency modes; all were larger than their female partners. Paired females represented two modes with mean CW ≈ 77 mm for pubescent and 99 mm for multiparous individuals. Only one to three of 176 male graspers were small-clawed (morphometrically immature), a statistically nonsignificant proportion; several others had partially regenerated claws but were otherwise morphometrically mature, as evidenced by the second right merus. These data support the hypothesis that the attainment of morphometric maturity, evidenced by a relatively large chela to body size ratio, is a prerequisite for functional maturity, the ability to mate competitively in wild populations.

scholarly journals Distribution and Size of Crab (Portunus pelagicus) in Betahwalang Waters, Demak, Central JavaSex Ratio, Size Distribution and Length-Weight Relationship of Portunus pelagicus Linnaeus, 1758 (Malacostraca : Portunidae) in Betahwalang, Demak, Central Java

2021 ◽  
Vol 24 (1) ◽  
pp. 133-140
Author(s):  
Sri Redjeki ◽  
Muhammad Zainuri ◽  
Ita Widowati ◽  
Ambariyanto Ambariyanto ◽  
Rudhi Pribadi ◽  
...  
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Sex Ratio ◽  
Size Distribution ◽  
Growth Parameters ◽  
Carapace Width ◽  
The Body ◽  
Swimming Crab ◽  
Portunus Pelagicus ◽  
Male And Female

Blue Swimming Crab (P. pelagicus, Linnaeus, 1758) is the main fisheries product from Betahwalang peoples. Fishing activity of Blue Swimming Crab by the fisherman almost every day in Betahwalang waters. Distribution and body size data of Blue Swimming Crab can be used for sustain management reference. The purpose of this study was to determine distribution pattern and body size of Blue Swimming Crab, started from July to November 2018 in Betahwalang waters, Demak. The data analyze consist of sex ratio, carapace width distribution and relationship between carapace width and body weight. 11790 samples Blue Swimming crab from Betahwalang waters consist of 7070 female crabs and 4720 male crabs. The result showed that sex-ratio between male and female crabs are balanced (1.0:1.37), with the most female crabs found at July and August. Body size distribution of male and female crabs are dominated in class 103-111 mm carapace width. Male and female crabs have a positive allometric on growth parameters, that means growth of the body weight is faster than carapace width. The result showed that Blue Swimming Crab in Betahwalang waters are support for sustainable fisheries. 

scholarly journals In vitro effects of artesunate on the survival of worm pairs and egg production of Schistosoma mansoni

2009 ◽  
Vol 83 (1) ◽  
pp. 7-11 ◽  
Author(s):  
Y. Mitsui ◽  
M. Miura ◽  
Y. Aoki
Keyword(s):  
Schistosoma Mansoni ◽  
Adult Worm ◽  
Survival Time ◽  
Egg Production ◽  
Inhibitory Effect ◽  
Male And Female ◽  
Paired Male ◽  
In Vitro Effects ◽  
Paired Female

AbstractThe effect of artesunate (ART) on the survival time of adult worm pairs of Schistosoma mansoni and on their egg output during in vitro culture was assessed. ART significantly decreased the survival time of both paired male and female worms at concentrations of 5, 10, 20 and 40 mg l− 1 during in vitro cultivation. An inhibitory effect of ART on the daily egg output of paired female worms during in vitro cultivation was also observed.

An ecological explanation for hyperallometric scaling of reproduction

2021 ◽  
Author(s):  
Tomos Potter ◽  
Anja Felmy
Keyword(s):  
Body Size ◽  
Reproductive Output ◽  
Resource Competition ◽  
Natural Populations ◽  
Scaling Exponent ◽  
Wild Populations ◽  
Wet Season ◽  
Size Dependent ◽  
In The Wild ◽  
The Relationship

AbstractIn wild populations, large individuals have disproportionately higher reproductive output than smaller individuals. We suggest an ecological explanation for this observation: asymmetry within populations in rates of resource assimilation, where greater assimilation causes both increased reproduction and body size. We assessed how the relationship between size and reproduction differs between wild and lab-reared Trinidadian guppies. We show that (i) reproduction increased disproportionately with body size in the wild but not in the lab, where effects of resource competition were eliminated; (ii) in the wild, the scaling exponent was greatest during the wet season, when resource competition is strongest; and (iii) detection of hyperallometric scaling of reproduction is inevitable if individual differences in assimilation are ignored. We propose that variation among individuals in assimilation – caused by size-dependent resource competition, niche expansion, and chance – can explain patterns of hyperallometric scaling of reproduction in natural populations.

The Parasitic Rhizocephalan Barnacle Sacculina Carcini in Crabs of the Forth Estuary, Scotland

1998 ◽  
Vol 78 (2) ◽  
pp. 665-667 ◽  
Author(s):  
S. Mathieson ◽  
A.J. Berry ◽  
S. Kennedy
Keyword(s):  
Carapace Width ◽  
High Tide ◽  
Carcinus Maenas ◽  
Size Class ◽  
Infection Rates ◽  
Lower Estuary ◽  
Male And Female ◽  
Sacculina Carcini ◽  
Middle Estuary

In the Forth Estuary, Scotland, parasitic rhizocephalan barnacle Sacculina carcini externae or scars occurred on 64% of Carcinus maenas from the subtidal channel of the middle estuary. These became more frequent downstream, infecting 46·9% in the lower estuary basin. Male and female crabs were infected equally, and infection rates in low-tide samples did not differ from high-tide. The parasites occurred most frequently on crabs of 40–50 mm carapace width (CW) rather than the modal crab size class of 50–60 mm. Downstream, proportionately more smaller than larger crabs bore parasites whereas, further upstream, more larger than smaller crabs bore parasites. There is evidence for the annual appearance of new externae in July-October, especially in the lower estuary basin, followed by their growth and loss after about a year.

scholarly journals The Composition of the Blood of the Shore Crab, Carcinus Moenas Pennant, in Relation to Sex and Body Size

1959 ◽  
Vol 36 (1) ◽  
pp. 113-119
Author(s):  
A. B. GILBERT
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Osmotic Pressure ◽  
Shore Crab ◽  
Male And Female ◽  
Blood Conductivity ◽  
Significant Difference

1. The influence of body size and sex on the total osmotic pressure (O.P.) and blood conductivity of the shore crab was investigated. 2. In both sexes the O.P. fell steadily as body weight increased. 3. At any body weight the O.P. of the blood of male crabs was significantly higher that that of females. 4. Blood conductivity increased in both sexes until a maximum was reached at a weight of about 35 g. Thereafter the conductivity fell as the weight increased. 5. There was no significant difference in blood conductivity between male and female crabs below 35 g. body weight. Above 35 g. the conductivity of males was significantly higher than that of females.

“Remedies” and Remedies

2020 ◽  
pp. 110-139
Author(s):  
Julie Hardwick
Keyword(s):  
Young People ◽  
Reproductive Health ◽  
Potential Risk ◽  
Informal Settlements ◽  
Male And Female ◽  
Female Partners ◽  
Occasional Occurrence ◽  
Women’S Reproductive Health ◽  
Women's Reproductive Health ◽  
Induce Abortion

Young people sought to resolve the challenge of untimely pregnancies in various ways. Male and female partners were involved with efforts to terminate the pregnancies—in effect, to induce abortion. Women’s reproductive health was potentially endangered both by the morbity of pregnancies and childbirth in pre-modern societies and by the potential risk of the “remedies” associated with attempting to end a pregnancy. A host of clergy, legal specialists, and friends and neighbors sought to support young couples in other ways by mediating informal settlements with the goal of ensuring safe deliveries and the welfare of the babies. In all of these efforts, working communities saw out-of-wedlock pregnancy as an inevitable if hopefully occasional occurrence to be managed pragmatically to secure the futures of all involved.

Challenges and advances in the study of pterosaur flight

2015 ◽  
Vol 93 (12) ◽  
pp. 945-959 ◽  
Author(s):  
K.M. Middleton ◽  
L.T. English
Keyword(s):  
Body Size ◽  
Size Range ◽  
Flapping Flight ◽  
Flight Mechanics ◽  
Wing Membrane ◽  
Membrane Function ◽  
Aerodynamic Modeling ◽  
History Of ◽  
Bone Loading

Pterosaurs have fascinated scientists and nonscientists alike for over 200 years, as one of the three known clades of vertebrates to have evolved flapping flight. The smallest pterosaurs were comparable in size to the smallest extant birds and bats, but the largest pterosaurs were vastly larger than any extant flier. This immense size range, coupled with poor preservation and adaptations for flight unknown in extant vertebrates, have made interpretations of pterosaur flight problematic and often contentious. Here we review the anatomical, evolutionary, and phylogenetic history of pterosaurs, as well as the views, perspectives, and biases regarding their interpretation. In recent years, three areas of pterosaur biology have faced challenges and made advances: structure of the wing membrane, function of the pteroid, body size and mass estimates, as well as flight mechanics and aerodynamics. Comparative anatomical and fossil study, simulated bone loading, and aerodynamic modeling have all proved successful in furthering our understanding of pterosaur flight. We agree with previous authors that pterosaurs should be studied as pterosaurs, a diverse but phylogenetically, anatomically, and mechanically constrained clade that can offer new insights into the diversity of vertebrate flight.

scholarly journals Stock Status of Blue Swimming Crab (Portunus pelagicus Linnaeus, 1758) in Tiworo Strait Waters, Southeast Sulawesi, Indonesia

2020 ◽  
Vol 25 (2) ◽  
pp. 85-90
Author(s):  
Yustika Permatahati Intan Permatahati ◽  
Nila Nikmatia Bugis ◽  
La Sara ◽  
Tezza Fauzan Hasuba Hasuba
Keyword(s):  
Carapace Width ◽  
Growth Patterns ◽  
Fishing Ground ◽  
Swimming Crab ◽  
Portunus Pelagicus ◽  
Male And Female ◽  
Gonad Maturity ◽  
Stock Status ◽  
Spawning Potential Ratio ◽  
Very High

The blue swimming crab (BSC) fishery in Tiworo Strait has been heavily exploited since two decades ago when its worldwide demand and price was very high. Study on population aspects of this organism in this waters is limited. The aim of present study was to investigate growth patterns, population stock status, and size at first gonad maturity of Portunus pelagicus. One of the main fishing ground of BSC around Tiworo Strait waters is at Bangko and Gala Islands. Samples of BSC were taken monthly using gillnet and collapsible trap. Each sample taken was identified its sex, measured its carapace width, and weighed. Data collected from fishing ground of BSC were analyzed to find out growth patterns, population stock status using spawning potential ratio (SPR) method, and the first gonad maturity (CW50). The results of study showed that growth patterns of BSC male and female following isometric growth patterns (b=0) (P<0.05). It was found out that SPR of BSC from both fishing ground was 22.46% and 23.71%, respectively which indicates that population stock status of BSC in Tiworo strait waters is “moderate level” (SPR > 20%). The size at first gonad maturity (CW50) was attained at carapace width of 9.16 cm for male and 10.16 cm for female. Those imply that BSCs allowed to be caught should be >10 cm. 

Receiver female body size and distances affect the claw-waving rate of signaller males in fiddler crabs (Brachyura, Ocypodidae)

Behaviour ◽  
2018 ◽  
Vol 155 (10-12) ◽  
pp. 905-914 ◽  
Author(s):  
Fahmida W. Tina ◽  
M. Jaroensutasinee ◽  
K. Jaroensutasinee
Keyword(s):  
Body Size ◽  
Female Body ◽  
Carapace Width ◽  
Fiddler Crabs ◽  
Female Body Size ◽  
Waving Display ◽  
Body Sizes ◽  
Males And Females ◽  
First Time ◽  
Close Distance

Abstract We tested for the first time how Austruca bengali Crane, 1975 signaller males adjusted their waving rates based on receiver female body sizes and their distances. We video recorded the waving display of 46 males (9–12 mm carapace width) for 30 s, and counted their waving rate. Receiver females were categorised as small (8–10 mm carapace width) and large (>10 mm). Distances between males and females were categorised as short (⩽12 cm) and long (>12 cm) distances. Our results indicate that males are able to measure distances and female sizes, and adjust their waving display by actively reducing waving rate (1) towards small females, as usually small females have lower fecundity compared to large ones and (2) towards females at very close distance because at this point, the females would make their mating decision, and thus males start to lead/hit the females towards their burrow rather than waving vigorously.

Aborigines - Was It Smallpox?

1987 ◽  
Vol 15 (5) ◽  
pp. 45-48
Author(s):  
B. Wright
Keyword(s):  
Shallow Water ◽  
Fresh Water ◽  
Male And Female ◽  
Aboriginal Australia ◽  
Sydney Harbour ◽  
Female Convicts ◽  
Port Jackson ◽  
Open Nature

When the fleet of British warships and transports led by H.M.S. Supply entered Botany Bay on the 18th of January 1788, the white invasion of Aboriginal Australia had begun. Captain Arthur Phillip in Supply was followed over the next two days by H.M.S. Sirius, six transports and three store ships. On the 26th January the Frenchman, La Perouse, with the ships La Boussole and L’Astrolabe, arrived at Botany Bay and remained there until the 10th of March, 1788. Because of the open nature of the bay, its shallow water and the lack of plentiful fresh water, Phillip decided to move the settlement, and on the 25th January sailed to Port Jackson (Sydney Harbour) in Supply, with the transports following on the 26th of January. The white invasion and occupancy of Australia started in reality when the whole of Phillip’s fleet and colonists were anchored at the east of Sydney Cove. On board Phillip’s eleven ships came 736 male and female convicts, 17 convict children, 211 marines accompanied by their wives and children.

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