Reproductive cycle of the fork-tailed catfish Arius graeffei Kner & Steindachner (Pisces : Ariidae) from the Clarence River, New South Wales

1985 ◽  
Vol 36 (1) ◽  
pp. 23 ◽  
Author(s):  
MA Rimmer
Keyword(s):  
Sex Ratio ◽  
Adult Female ◽  
Reproductive Cycle ◽  
Ovarian Development ◽  
New South ◽  
New South Wales ◽  
Dorsal Surface ◽  
Fish Length ◽  
Adult Males ◽  
South Wales

A. graeffei breeds annually from early November to early December when water temperatures reach 26°C and daylength averages 13.7 h. The bulk of ovarian development is restricted to the 2 months before spawning; the rate of oocyte development varies substantially between individuals. Diameters of mature oocytes range from 11.0 to 13.7 mm (mean 12.2 mm). Fecundity ranges from 40 to 122 and is linearly related to fish length and weight. The sex ratio of the population studied was 0.82 with a preponderance of males. The pelvic fins of adult female A. graeffei are longer and more rounded than those of adult males, and have a hook-like thickening (clasper) on the dorsal surface which develops seasonally in association with the reproductive cycle. Although marine populations of A. Graeffei appear to undertake extensive anadromous migrations associated with breeding, no such movements were observed in the fluviatile population studied.

The effects of age, sex, reproductive status and temporal factors on the time-use of free-ranging red kangaroos

1993 ◽  
Vol 20 (6) ◽  
pp. 785 ◽  
Author(s):  
DM Watson ◽  
TJ Dawson
Keyword(s):  
Body Size ◽  
Group Size ◽  
Time Use ◽  
New South ◽  
New South Wales ◽  
Time Of Day ◽  
Adult Males ◽  
South Wales ◽  
Free Ranging ◽  
Foraging Time

The effects of temporal (time of day and season) factors and size, sex, female reproductive state and group size on the diel time-use of free-ranging red kangaroos (Macropus rufus) was examined. Particular emphasis was given to the effects on their foraging behaviour, with foraging divided into cropping, chewing and searching components. The study was conducted in semi-arid western New South Wales from July 1991 to March 1992, a time of deepening drought conditions in New South Wales. Group size had very little influence on the time-use of M. rufus. It was negatively but only weakly correlated with the proportion of foraging time spent chewing (chewing intensity). No significant differences in time-use were found between size classes of adult males (large and medium-sized males), females with or without pouch young, or females with different-sized pouch young (no visible young, small pouch young or large pouch young). Differences occurred between adult males, adult females and subadult kangaroos. These differences were mainly associated with their chewing and searching behaviour and were related to body size; as body size increased the proportion of time spent chewing and the intensity of chewing increased while the proportion of time searching and the proportion of foraging time spent searching (searching intensity) decreased. Neither the proportion of time spent cropping or foraging nor the proportion of foraging time spent cropping (cropping intensity) or the proportion of active time spent foraging (foraging intensity) differed between any size/sex/reproductive class. Temporal effects had a considerable influence on time-use. M. rufus were most active at night and in the few hours after sunrise and sunset. Seasonal changes in time-use were largely a result of changes in daytime behaviour. M. rufus foraged less and rested more during the day in winter than in spring or summer. There was no increase in the intensity or proportion of time spent foraging or cropping at night to compensate for the reduction in diurnal foraging. It is hypothesised that temporal variations in time-use were related to variations in weather and vegetation conditions.

Helenococcus, A New Genus of Diaspididae with Description of a New Species, Helenococcus hokeae (Homoptera: Coccoidea) from Australia

1997 ◽  
Vol 32 (1) ◽  
pp. 72-78
Author(s):  
Tong-Xian Liu ◽  
James O. Howell
Keyword(s):  
New Species ◽  
Adult Female ◽  
Type Species ◽  
New Genus ◽  
New South ◽  
New South Wales ◽  
First Instar ◽  
South Wales ◽  
A New Species

Helenococcus, a new genus of Diaspididae, is described and designated, including detailed illustrations and descriptions of the adult female, second instar, and first instar of the type species, Helenococcus hokeae. The new species was collected on Hokea pampliniana from New South Wales, Australia.

Population Parameters of Two Congeneric Possums, Trichosurus spp., in Norh Eastern New South Wales

1981 ◽  
Vol 29 (2) ◽  
pp. 205 ◽  
Author(s):  
RA How
Keyword(s):  
Breeding Season ◽  
New South ◽  
New South Wales ◽  
Adult Males ◽  
Population Parameters ◽  
Bond Population ◽  
South Wales ◽  
Open Forest ◽  
Adult Sex Ratio ◽  
Population Strategy

In adjacent areas in north-eastern New South Wales, T. vulpecula occurs in the open forest and woodland and T. caninus occurs in the closed and tall open forest; both species are found in the pine plantation. T. vulpecula has a single breeding season in autumn when all females 1 y old and older reproduce. The young become independent around 175 days old and disperse at up to 2 y old. Mortality is low (15%) among dependent young but considerably higher among independent dispersing individuals. T. caninus also has a single autumn breeding season. The young become independent around 240 days old but disperse after 18-26 months, females moving before males. Mortality is high (56%) among dependent young but less so among subadults. An adult sex ratio of parity is the result of a higher survival among subadult males than females offsetting the reverse in adults. Some 2-y-old and all 3-y-old females reproduce but a few older females fail to breed in certain years. There is evidence that the high mortality of dependent young and failure of older females to breed is associated with offspring of previous years remaining in the population. Adult males and females appear to form a pair-bond. Population parameters of T. vulpecula described from other areas show considerable variation; this flexibility in population strategy explains the species' success in occupying a diversity of habitats and rapidly colonizing new areas.

No evidence for seasonality in the ectoparasitic fauna of slimy mackerel, Scomber australasicus

1993 ◽  
Vol 44 (5) ◽  
pp. 709 ◽  
Author(s):  
KML Perera
Keyword(s):  
Seasonal Variation ◽  
New South ◽  
New South Wales ◽  
Fish Length ◽  
South Wales ◽  
Trypanorhynch Cestode

Fifteen (or sixteen) species of ectoparasites-6 monogeneans, 4 (or 5) trematodes, 2 copepods, 1 isopod, 1 cestode, and unidentified cysts -were collected from 428 Scomber australasicus individuals caught at Eden, New South Wales, Australia, between November 1988 and June 1992. Neither common nor rare parasites of slimy mackerel showed seasonal variation in abundance or prevalence. Only the copepod Brachiella magna occurred more frequently on larger (older) fish than smaller (younger fish). Two monogeneans (Kuhnia scombri, Pseudokuhnia minor), 2 didymozoids, and unidentified cysts occurred more frequently on smaller than larger fish. The intensities of the remaining monogeneans (Kuhnia scombercolias, Kuhnia sprostonae and Grubea australis), 1 didymozoid, 1 copepod (Peniculus sp.), the isopod (Ceratothoa imbricata) and a trypanorhynch cestode were not significantly correlated with fish length.

Studies on Age, Growth, and Life History of the Pilchard, Sardinops neopilchardus (Steindachner), in Southern and Western Australia

1950 ◽  
Vol 1 (2) ◽  
pp. 221 ◽  
Author(s):  
JM Blackburn
Keyword(s):  
Growth Rate ◽  
Western Australia ◽  
New South ◽  
New South Wales ◽  
South Australia ◽  
The Body ◽  
Fish Length ◽  
Linear Type ◽  
Spawning Period ◽  
South Wales

The biology of the unexploited Australian pilchard, Sardinops neopilchardus (Steindachner), was studied from a limited material available from Victorian, Tasmanian, South Australian, and Western Australian waters. This completes the preliminary study of the species over almost the whole of its sub-continental range. In Victorian waters, the surface shoaling season is spring and summer, in South Australia, summer and autumn, and in southern Western Australia, autumn and winter; these are the spawning seasons for the respective areas. In New South Wales and Queensland waters, the shoaling season is autumn to spring, which is again a spawning period. The situation in Tasmania, where the species is rare, is probably similar to that in Victoria. On the west coast of Australia, where the species extends northward to the Tropic of Capricorn (as it also does in the east) the seasonal distribution is not clear. In all these areas pilchard occurrences are virtually limited to the bay and neritic waters. Victorian pilchards attain mean standard lengths of about 8.0, 10.5, 12.5, 14.0, and 15.5 cm. at the ages of one, two, three, four, and five years respectively. This growth rate is considerably lower than that in New South Wales. In southern Western Australia the growth rate is intermediate between the other two, but in South Australia it was not established. The average size of pilchards in the seasonal shoals appears to be greater in Western Australia than elsewhere, but no fish over 19.5 cm. standard length (9.0 in. total length) has been encountered in any of the current Australian investigations. Sexual maturity occurs earlier in Victoria than in New South Wales, sometimes at one year of age. The ring pattern of Australian pilchard scales is complex, involving yearly, spawning, and secondary rings. A hypothesis to account for the formation of spawning rings is outlined, and an earlier hypothesis relating to yearly rings is abandoned. Secondary rings occur on most scales from the same fish. In all waters the season of ring formation coincides with that of surface availability of fish, but in Victoria it is also the growing season, which makes age determination particularly difficult. The fish-length/scale-length relationship for Victorian material is of the same linear type as for New South Wales, but there are differences in the size of scales taken from the same area of the body. The possible influences of distribution, size, and condition of fish on future economic exploitation are discussed.

Distribution and Aspects of the Biology of the Parma Wallaby, Macropus parma, in New South Wales

1977 ◽  
Vol 4 (2) ◽  
pp. 109 ◽  
Author(s):  
GM Maynes
Keyword(s):  
New South ◽  
New South Wales ◽  
Embryonic Diapause ◽  
Body Measurements ◽  
Adult Males ◽  
Limited Data ◽  
Adult Females ◽  
South Wales ◽  
Sclerophyll Forest ◽  
The Mean

M. pauma, which was formerly thought to be extinct in Australia, has been found in the Great Dividing Range of coastal New South Wales between 29D 28' and 32D 23's. The optimum habitat appears to be areas of wet sclerophyll forest with a thick shrubby understorey in association with grassy areas. Although the species may be locally common, its present status is best defined as rare; it has a limited distribution and normally occurs at a low density throughout its range. Limited data indicate that most young are born between February and June. Two of six females examined were probably in embryonic diapause. Females may mature sexually as early as 12 months old, and at a weight of 2.6-2.8 kg. Adult females in Australia were significantly heavier than those in New Zealand (Kawau I.), and larger in seven external body measurements. In contrast, adult males were significantly larger in Australia than Kawau I. in ear length only. The species is mainly nocturnal and the mean group size is 1.34 animals, i.e. it is usually single individuals that are encountered.

Reproduction of the turban shell Turbo torquatus Gmelin 1791 (Mollusca : Gastropoda), in New South Wales, Australia

2002 ◽  
Vol 53 (1) ◽  
pp. 85 ◽  
Author(s):  
D. W. Ward ◽  
A. R. Davis
Keyword(s):  
Reproductive Cycle ◽  
Developmental Stages ◽  
New South ◽  
Gonadosomatic Index ◽  
New South Wales ◽  
Gonad Development ◽  
Gonadal Development ◽  
Small Scale ◽  
Frequency Distributions ◽  
South Wales

The Sydney turban shell Turbo torquatus is the focus of a small-scale commercial fishery in New South Wales. Effective management requires knowledge of the reproductive biology, yet this is lacking for NSW waters. The reproductive cycle was investigated at three localities on the southern New South Wales coast. Samples of T. torquatus were collected monthly at Wollongong, Ulladulla and Eden from February 1996 until August or December 1997. The reproductive cycle was investigated by three methods: monthly determination of a gonadosomatic index, estimation of oocyte size-frequency distributions and classification of female gonads into developmental stages following histological sectioning. Males and females within a population underwent synchronous gonad development and spawning. Spawning events were often protracted over a period of several months with females in various stages of gonadal development. Two spawning events occurred each year, with a spawning event in autumn–winter and another in spring–summer. These events were asynchronous among the three localities, and partial spawning appeared to be a common occurrence. Owing to variation in the timing of spawning between populations separated by a distance as small as 15 km, seasonal closures to protect spawning stocks are unlikely to be effective.

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