Reproductive biology of the eastern shovelnose stingaree Trygonoptera imitata from south-eastern Australia

2009 ◽  
Vol 60 (8) ◽  
pp. 845 ◽  
Author(s):  
Fabian I. Trinnie ◽  
Terence I. Walker ◽  
Paul L. Jones ◽  
Laurie J. Laurenson
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Rapid Growth ◽  
Extended Period ◽  
In Utero ◽  
Anthropogenic Pressures ◽  
Eastern Australia ◽  
The Family ◽  
Mean Size ◽  
Size At Birth

In applying a quantitative approach to the reproduction of Trygonoptera imitata, the present study contributes to understanding the wide diversity in the reproductive biology of the family Urolophidae and provides insights to help determine phylogenetic relationships. This localised species is taken as bycatch in several inshore fisheries and potentially impacted by a range of other anthropogenic pressures, including introduced species, particularly in shallow-water pupping areas. T. imitata can be characterised as a species of comparatively low matrotrophic histotrophy with an extended period of relatively large eggs in utero (5–8 months) followed by rapid growth of the embryos (4–6 months). The reproductive cycle is annual with parturition occurring during late-February–April, followed immediately by ovulation. Mean size-at-birth is ~225 mm total length and there is a ~1000% gain in mean wet mass from egg (15 g) to full-term embryo in utero (150 g), the lowest reported for any viviparous batoid. Litter size increases with maternal length, reaching a maximum of seven, and sex ratio of embryos is 1 : 1. Maximum length and estimates of the maturity–ogive parameters l50 and l95 are similar for females and males.

Distribution, size and sex composition, reproductive biology and diet of sharks from Northern Australia

1991 ◽  
Vol 42 (2) ◽  
pp. 151 ◽  
Author(s):  
JD Stevens ◽  
KJ McLoughlin
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Annual Cycle ◽  
Post Partum ◽  
Austral Summer ◽  
Size Composition ◽  
Maximum Size ◽  
Northern Australia ◽  
Average Size ◽  
Size At Birth

The distribution, size composition, sex ratio, reproductive biology and diet of 17 species of shark from the families Triakidae, Hemigaleidae and Carcharhinidae from northern Australia were examined. In most of these species the sex ratio of the embryos is 1 : 1, whereas in the post-partum populations there were significantly more males than females. The results indicate four broad reproductive strategies among these sharks. In most species reproduction was distinctly seasonal with individual females giving birth each Austral summer (annual cycle) after a gestation period of 9-12 months. A second group had a very similar cycle except that individual females gave birth every second year (biennial cycle). A third group had an annual cycle but breeding was continuous throughout the year, these were mostly small bottom-associated sharks. One species had a seasonal cycle but gave birth twice each year (biannual cycle) after a 6-month gestation. The average size at birth varied from 27 to 75 cm and the average litter size varied from 2 to 34. The size at birth was about 40% of the size at maturity, which in turn was about 70% of the maximum size. Diets ranged from omnivorous to highly selective. Fish was an important component of the diet in all but one species. There was evidence of partitioning of food resources among sympatric, morphologically similar, sharks.

Reproductive biology of the pelagic stingray, Pteroplatytrygon violacea (Bonaparte, 1832), in the equatorial and south-western Atlantic Ocean

2014 ◽  
Vol 65 (11) ◽  
pp. 1035 ◽  
Author(s):  
D. P. Veras ◽  
F. H. V. Hazin ◽  
I. S. L. Branco ◽  
M. T. Tolotti ◽  
G. H. Burgess
Keyword(s):  
Sex Ratio ◽  
Atlantic Ocean ◽  
Reproductive Biology ◽  
Sexual Maturity ◽  
Pregnant Female ◽  
Longline Fishery ◽  
Western Atlantic ◽  
Pregnant Females ◽  
Size At Birth ◽  
Tuna Longline

From October 2005 to March 2010, a total of 480 pelagic stingray, Pteroplatytrygon violacea, specimens, 188 females and 292 males (0.64 female : 1 male), were taken in the equatorial and south-western Atlantic by the commercial tuna longline fishery and their reproductive biology was studied. Disc widths (DW) ranged from 28.0 to 66.0 cm for females and from 34.0 to 59.6 cm for males. Size at first sexual maturity was estimated at ~48.0 cm DW (first pregnant female) for females and ~41.0 cm DW for males. Ovarian fecundity, considering only follicles larger than 0.5 cm in diameter, ranged from 1 to 17 follicles per female, while the uterine fecundity of embryos in pregnant females in Stages 2 and 3 ranged from 1 to 5 embryos per female. The sex ratio between the embryos was almost equal (1.08 female : 1 male) and the size at birth was 19.0 cm DW.

Aspect of the reproductive biology of the Gummy Shark, Mustelus antarcticus Gunther, from waters off the South coast of Western Australia

1990 ◽  
Vol 41 (6) ◽  
pp. 807 ◽  
Author(s):  
RCJ Lenanton ◽  
DI Heald ◽  
M Platell ◽  
M Cliff ◽  
J Shaw
Keyword(s):  
Reproductive Biology ◽  
Western Australia ◽  
Seasonal Changes ◽  
Sexual Maturity ◽  
Post Partum ◽  
Target Species ◽  
Eastern Australia ◽  
Mean Size ◽  
The Mean ◽  
Major Target

The gummy shark (Mustelus antarcticus) is a major target species in two substantial shark fisheries that operate in temperate Australian waters. Data on the reproductive biology of M. antarcticus in the waters off south-western Australia were obtained from samples collected by commercial vessels operating from Albany to Esperance, Western Australia. The samples contained a ratio of four females to one male. M. antarcticus is a viviparous, aplacental species. Males mature at a smaller size than females. Since the overwhelming majority of sharks sampled were mature, it was not possible to estimate precisely the mean size at which sexual maturity was attained. Examination of seasonal changes in the development of ova and testes, in uterine contents, and in embryo growth established that the period of parturition, mating and ovulation occurred over the 3 months between early November and early February. The gestation period was 11-12 months. Full-term embryos ranged in size from 30 to 36 cm total length and occurred in a sex ratio of one male to one female. The ovarian and gestational cycles proceed concurrently, with reproduction occurring annually. Only one of the 224 females analysed for uterine content was considered to be in a true post-partum condition. The number of embryos (N) per mother increased with the length of the mother (L) according to the regression N = exp(-4.13398 + 0.049171L). The reproductive biology of females collected off Albany and Esperance differed in some respects from that of females collected off south-eastern Australia.

Reproductive biology of the protogynous hermaphrodite Achoerodus viridis (Labridae) from south-eastern Australia

1995 ◽  
Vol 46 (7) ◽  
pp. 999 ◽  
Author(s):  
BM Gillanders
Keyword(s):  
Population Structure ◽  
Sex Ratio ◽  
Reproductive Biology ◽  
Age Classes ◽  
South Eastern ◽  
Eastern Australia ◽  
Protogynous Hermaphrodite ◽  
Mature Fish ◽  
A Site ◽  
Gonadal Structure

Achoerodus viridis (Pisces : Labridae) was sampled over two years at Little Bay, NSW, Australia, and comparative material was taken from a site 4.5 km away at Cape Solander. Population structure and gonadal structure showed that A. viridis was protogynous and monandric (i.e. no primary males were found). Histological sections of male gonads showed a gonadal lumen, general ovarian lamellar form and multiple sperm ducts running longitudinally through the gonad wall. Males dominated the larger size and age classes, whereas females predominated in the smaller size and age classes. The sex ratio of mature fish and the whole population was biased in favour of females. Individuals at both sites matured as females at 1+-2+ years. Fish at Little Bay functioned as females at ages ranging from 8+ to 18+ years before changing sex at a size between 480 and 580 mm SL. Fish at Cape Solander may function as females for up to 18+' years and change sex between 500 and 520 mm SL. Spawning occurred between July and October (1991-93).

Reproductive biology of the whiskery shark, Furgaleus macki, off south-western Australia

1998 ◽  
Vol 49 (7) ◽  
pp. 687 ◽  
Author(s):  
Colin A. Simpfendorfer ◽  
Philip Unsworth
Keyword(s):  
Linear Relationship ◽  
Reproductive Biology ◽  
Western Australia ◽  
Fork Length ◽  
Size Selectivity ◽  
Pregnant Females ◽  
Gill Net ◽  
The Family ◽  
Second Year ◽  
Size At Birth

The whiskery shark, Furgaleus macki, is important in the commercial shark fishery off southern Western Australia. The reproductive biology was studied with the aid of 88 specimens collected by commercial gill-net vessels off south-western Australia between March 1994 and August 1996. The size selectivity of the gill-nets resulted in only mature and large juvenile specimens being caught. Size at birth was estimated to be 22–27 cm total length. Size (fork length) at maturity was 107 cm for males and 112 cm for females. There is a seasonal reproductive cycle. Mating is most likely to occur from August to September, with females storing spermatozoa until ovulation in late January to early April. Gestation lasts 7–9 months, with parturition from August to October. Litter sizes vary from 4 to 28 (mean 19). There was a significant linear relationship between litter size and maternal length. Mature males mate each year, but females produce litters every second year. Mature non-pregnant females develop large yolky ova from March to October, with development of the ova completed several months before ovulation. The results are compared with previous records and with data for other species of the family Triakidae that occur off southern Australia.

Breeding of Philander frenata (Didelphimorphia, Didelphidae) in captivity

1998 ◽  
Vol 32 (4) ◽  
pp. 434-438 ◽  
Author(s):  
Erika Hingst ◽  
Paulo Sergio D'Andrea ◽  
Ricardo Santori ◽  
Rui Cerqueira
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Litter Size ◽  
Breeding Success ◽  
Gestation Period ◽  
Sex Ratio At Birth ◽  
Laboratory Management ◽  
Sensory Contact ◽  
In Captivity ◽  
Size At Birth

Data on the reproductive biology and laboratory management of Philander frenata are presented here. Sensory contact before pairing increased breeding success and reduced aggression between pairs. Gestation period was 13–14 days, with a post-lactation oestrous. Births occurred only between August and February. Mean litter size at birth and at weaning was 5.5 (SD=2.4) and 4.0 (SD=1.9), respectively. Sex ratio at birth was statistically biased toward males. The timing of weaning was established at between 70 and 80 days old, with the young weighing from 24 g to 49 g.

scholarly journals Reproductive Biology of Round Sardinella (Sardinella Aurita) (Valenciennes, 1847) in Senegalese Coastal Waters

2018 ◽  
Vol 9 (1) ◽  
pp. 31
Author(s):  
Ismaïla NDIAYE ◽  
Alassane SARR ◽  
Alioune FAYE ◽  
Modou THIAW ◽  
Malick DIOUF ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Coastal Waters ◽  
Sexual Maturity ◽  
Reproductive Parameters ◽  
Monthly Variation ◽  
Relative Fecundity ◽  
The Mean ◽  
Sardinella Aurita ◽  
Somatic Index

In this study, a total of 1068 specimens Sardinella aurita of which 553 females and 515 males were examined. The objectif of this study was to determine the reproductive parameters of Sardinella aurita. The sex ratio was significantly in favor of females (55%). The size at first sexual maturity was estimated at 18.9 cm for females and 18.0 cm for males. The monthly variation of sexual maturity stages and gonado-somatic index (GSI) allowed to locate the reproduction periods from February to June and from September to December. The mean absolute fecundity was estimated at 110.794 ± 7582 oocytes whereas relative fecundity was about 422 ± 26 oocytes per gram of female.

scholarly journals Uterine fluid composition of the dwarf ornate wobbegong shark (Orectolobus ornatus) during gestation

2011 ◽  
Vol 62 (6) ◽  
pp. 576 ◽  
Author(s):  
Megan T. Ellis ◽  
Nicholas M. Otway
Keyword(s):  
Reproductive Biology ◽  
Coastal Waters ◽  
Reproductive Strategies ◽  
Yolk Sac ◽  
Gestation Period ◽  
Fluid Composition ◽  
Complex Composition ◽  
Eastern Australia ◽  
Uterine Fluid ◽  
Low Levels

Low fecundity in chondrichthyans makes them extremely susceptible to fishing, so understanding the various reproductive strategies in this group is vital for management. Knowledge of the uterine fluid (UF) composition throughout gestation is fundamental to this understanding, yet is restricted to a few species. This study focussed on the UF composition of the wobbegong (Orectolobus ornatus), which inhabits coastal waters off eastern Australia. The UF was quantified throughout pregnancy. Fluids surrounding uterine eggs had a complex composition, with mean urea (98.48 mmol L–1), sodium (560.25 mmol L–1) and potassium (13.93 mmol L–1) concentrations significantly greater than those in seawater. A change in composition, from complex to simple, occurred after 3–4 months gestation. Major electrolyte concentrations then resembled seawater for the remainder of gestation, suggesting the flushing of the uteri with seawater and evidenced by fluctuating low levels of urea. The gestation period reflected the time for metabolism of yolk stores, osmotic and ionic adjustment, development of functioning immunological systems and prevention of external yolk sac damage. Our study is the first documentation of UF composition for a wobbegong shark and increases understanding of its reproductive biology.

Studies in Ovipositional Behaviour and Control of Sex in Aphytis Melinus Debach, a Parasite of California Red Scale, Aonidiella Aurantii (Mask.).

1974 ◽  
Vol 22 (2) ◽  
pp. 231 ◽  
Author(s):  
I Abdelrahman
Keyword(s):  
Sex Ratio ◽  
Host Density ◽  
Adult Emergence ◽  
The Body ◽  
Maturation Stage ◽  
Aphytis Melinus ◽  
Egg Maturation ◽  
Mean Size ◽  
Accepted Practice ◽  
And Control

The growing adult female red scale was the most preferred stage for A. melinus, followed by the second growing instar and lastly the male prepupa. The numbers of scale parasitized, the total of eggs laid, the number of eggs per scale, sex ratio and size of the parasites produced were all ranked in the same order. The mean size of parasites produced within the third instar decreased as the number of parasites per host increased. In the absence of the preferred host stages, female A. melinus laid readily in the unpreferred stages. In both A. melinus and A, chrysomphali it was noted that in multi- parasitism pupation, pupal development and adult emergence of all parasites in one host were synchronized. In A. melinus the sex and number of eggs laid per host are influenced by the host's size and quality. When A. melinus laid more than one egg in one host, it laid female eggs first and male eggs later; apparently the spermatheca goes through a period of fatigue, and is incapable of delivering sperm to the eggs descending the oviduct. Sex ratio decreases with increase in number of parasites per host and density of parasite population relative to hosts. The deposition of parasite eggs in a host by one female was observed during a short cycle of oviposition. A. melinus laid its eggs both 'above' and 'below' the body of the scale, whereas A. chrysomphali did so exclusively 'below'. In young mated A. melinus, eggs laid above the body of the scale were females and those below were males, but in old mated females all eggs, wherever laid, were male. Host development stops as soon as a parasite egg is laid. A. melinus avoids laying eggs in already parasitized hosts. The stages of red scale were ranked according to the percentage of mutilated individuals as: first moult (most mutilated), second instar, first instar, third instar, male prepupa and male pupa; second-moult females, egg-maturation stage and crawler-producing stage were unmutilated. A. melinus sometimes partitions her clutch of eggs into two hosts, particularly when host density is high. Partitioning in A. melinus may substitute for the generally accepted practice of super- parasitism, which would not be appropriate because the parasite is able to distinguish between parasitized and unparasitized hosts, is able to sense host density and to distribute her progeny on available hosts. Partitioning is advantageous for biological control. Behaviour of oviposition, mutilation and mutilation feeding in A. melinus are described in detail.

Biology of lake sturgeon (Acipenser fulvescens) spawning below a dam on the Richelieu River, Quebec: behaviour, egg deposition, and endocrinology

2013 ◽  
Vol 91 (3) ◽  
pp. 175-186 ◽  
Author(s):  
J.D. Thiem ◽  
D. Hatin ◽  
P. Dumont ◽  
G. Van Der Kraak ◽  
S.J. Cooke
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Residence Time ◽  
Lake Sturgeon ◽  
Blood Sampling ◽  
Acipenser Fulvescens ◽  
Spawning Ground ◽  
Egg Deposition ◽  
Daily Spawning ◽  
Gill Netting

Knowledge of the reproductive biology of wild sturgeon populations is critical to ensure the survival of this unique group of animals. We combined gill-netting surveys, nonlethal blood sampling, radiotelemetry, and egg collection to examine the reproductive biology of lake sturgeon (Acipenser fulvescens Rafinesque, 1817) at a suspected spawning ground below a dam on the Richelieu River, Quebec. Lake sturgeon were present at the beginning of sampling in early May, and spawning took place from 26 May to 5 June when water temperature averaged 13.4 ± 0.1 °C (range 11.5–15.5 °C). Daily spawning population estimates ranged from 285 to 1282 individuals and the sex ratio of spawners was estimated at 2.1 males per female. The presence of radio-tagged individuals on the spawning grounds peaked from 20 to 28 May, corresponding with known spawning bouts. Residence time of spawners on the spawning ground ranged from 1 to 27 days (median = 5 days) and there were no differences in residence time between sexes. Nonlethal blood sampling enabled the quantification of steroid levels to determine the spawning population sex ratio, and steroid levels were highest before spawning was known to occur and decreased concurrently with, and after, known spawning events.

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