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.

The Season of Birth of Anxiety Neuroticsr

1978 ◽  
Vol 12 (1) ◽  
pp. 69-71 ◽  
Author(s):  
Gordon Parker
Keyword(s):  
Seasonal Variation ◽  
New South ◽  
New South Wales ◽  
Season Of Birth ◽  
Anxiety Neurosis ◽  
South Wales

An association between spring birth and anxiety neurosis in New South Wales is confirmed. Two possible explanations, that the association might reflect a seasonal variation in conceiving or in giving birth among mothers of those with significant anxiety, or that spring birth selectively disposes to anxiety, were examined. Findings suggest that both effects may be operating.

Seasonal variation in reproductive performance of Merino ewes in northern New South Wales

1962 ◽  
Vol 2 (4) ◽  
pp. 69 ◽  
Author(s):  
JF Barrett ◽  
TF Reardon ◽  
LJ Lambourne
Keyword(s):  
Seasonal Variation ◽  
Birth Weight ◽  
Reproductive Performance ◽  
New South ◽  
New South Wales ◽  
Early Summer ◽  
The Other ◽  
South Wales ◽  
Group A

Two groups of Merino ewes were observed for five years to determine the variation within years and to make comparisons between years in the numbers of ewes exhibiting oestrus, in fertility, and in lamb birth weights. A group of 35 ewes (continuous), was run constantly with vasectomized rams and services were recorded. From the other (changing) group, a fresh sub-group of 15 ewes was joined with fertile rams every four to six weeks; services were recorded, together with lambing performance and lamb birth weights.Distinct breeding and anoestrous seasons similar to those shown by other workers were observed in both groups of ewes. However, the onset of oestrous activity was a month earlier in the changing ewes than in the continuous ewes.Fertility was low during spring and early summer and reached a maximum in autumn.The birth weight of the lambs appeared to be predominantly influenced by the ewes' nutrition during pregnancy.

Seasonal variation in the fertility and fecundity of Bungaree and Peppin Merinos in central-western New South Wales

1969 ◽  
Vol 9 (37) ◽  
pp. 151 ◽  
Author(s):  
JR Giles ◽  
JP Drinan
Keyword(s):  
Seasonal Variation ◽  
Agricultural Research ◽  
New South ◽  
New South Wales ◽  
Ovulation Rate ◽  
Research Station ◽  
Agricultural Research Station ◽  
South Wales

The seasonal variation in fertility and fecundity of Bungaree and Peppin Merinos was compared at the Agricultural Research Station, Trangie, New South Wales. Ewes of both strains were joined to rams of both strains for 32 days on nine occasions ; each joining being separated from adjacent periods by an interval of 10 days. For six weeks after joining the ewes were run with vasectomized rams and were then slaughtered over the following six weeks. Incidence of oestrus and ovulation rate of the two strains were similar at all times. More Bungaree than Peppin ewes returned to service, particularly during the autumn, irrespective of the strain of rams to which they were joined. There was no difference between ram strains in percentage of ewes returning to service or percentage of ewes pregnant, but a significantly higher proportion of ova were lost in pregnant ewes with multiple ovulations after joining to Bungaree rams in winter and spring.

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.

The occurrence of the Pygmy Right Whale Caperea marginata (Cetacea: Neobalaenidae), along the Australian coast.

1992 ◽  
Vol 15 (1) ◽  
pp. 1
Author(s):  
C.R. Pavey
Keyword(s):  
Seasonal Variation ◽  
Western Australia ◽  
New South ◽  
New South Wales ◽  
South Australia ◽  
Gestation Period ◽  
Right Whale ◽  
South Wales ◽  
Northern Edge

The occurrence of Caperea marginata, based on strandings, along the mainland coast of Australia was investigated and compared with Tasmanian records. Details were obtained for 29 mainland and 38 Tasmanian reports to March 1989. Mainland strandings of C. marginata were spatially clumped, with 19 records from South Australia and within this state, eight from Kangaroo Island and five from Port Lincoln Bay. The most northerly records were from Nowra (New South Wales) and Fremantle (Western Australia). The majority of mainland strandings were juveniles recorded from September-January, although C. marginata has also stranded during April-June. Tasmanian records extended throughout the year and animals stranded were mostly adults. The proportion of adults to juveniles was significantly lower for the mainland (nine adult, II juvenile) than Tasmania (21 adult, three juvenile), indicating that juveniles occur more frequently at the northern edge of the species' distribution. Examination of seasonal variation in length of foetal, calf and juvenile records indicated a gestation period of about 10 months and a weaning period of about 5 months. There appears to be a broad mating, calving and weaning period over some 8 months.

A Biological Study of the Anchovy, Engraulis australis in Australian Waters

1950 ◽  
Vol 1 (1) ◽  
pp. 3 ◽  
Author(s):  
M Blackburn
Keyword(s):  
Growth Rate ◽  
Life History ◽  
New South ◽  
New South Wales ◽  
Border Region ◽  
Biological Study ◽  
Fish Length ◽  
Slight Variation ◽  
Scale Reading ◽  
South Wales

A biological study was made of the common Australian anchovy, Engraulis australis (White), which occurs in coastal waters south of the Tropic of Capricorn. The occurrences in Victorian waters, where the only fishery exists, were those most fully investigated. There are three subspecies which are easily recognized by their mean vertebra numbers, in combination with the region of occurrence. E. a. australis (White) occurs in Queensland and in all but the southernmost waters of New South Wales. E a antipodum Gunther ranges from the border region of New South Wales through Victorian, Tasmanian, and South Australian waters. E. a. fraseri n, subsp. occurs in Western Australia. Each subspecies is further divided into local populations which intergrade. The subspecies antipodtim grows to about 2.3, 2.9, 3.5, 4.2, and 4.7 inches of total length (mean sizes) at 1/2, 1 1/2, 2 1/2, 3 1/2:, and 4 1/2: years respectively, The greatest known length is 6.2 inches. Sexual maturity is usually attained at 1 year. Spawning occurs mainly in the inlets, in summer. The fish inhabit principally the inlet waters, but as they become older they tend to move out to sea in winter and return in spring. n'ithin the inlets, the younger fish are usually found furthest from the sea. There is a special brackish-water population in the rivers entering the Gippsland Lakes. The growth rate of the subspecies australis is similar to that of antipodum, but the life history ppears to differ in many ways, although the full facts are not clear. There is more spawning in the colder months, and it takes place mainly at sea. The subspecies fraseri occurs both in inlets and at sea, but the data are insufficient to establish the life history. The growth rate is approximately the same as elsewhere. Anchovies occur in large numbers in certain inlets, where they can be caught easily with haul seines. In Port Phillip Bay there are proficient anchovy fishermen who cannot dispose of much of the fish they are able to catch. The fish would be suitable for canning whole, for fish paste (for which a little is used now) and for live-bait for tuna fishing. They would not be suitable for oil reduction. The scale-reading (age) studies yielded some results of general academic interest. The fish-length/scale-length relationship is not the same in all regions, and this affects calculations of gvowth rate. There is slight variation in growth rate between localities, and possibly between year classes and sexes; and apparent but not real variation between age-groups, and between different sizes in each age-group.

Role of the crayfish Cherax destructor clark as food for trout in Lake Eucumbene, New South Wales

1983 ◽  
Vol 34 (3) ◽  
pp. 407 ◽  
Author(s):  
RA Faragher
Keyword(s):  
Rainbow Trout ◽  
Brown Trout ◽  
Salmo Trutta ◽  
New South ◽  
New South Wales ◽  
Water Levels ◽  
Size Analysis ◽  
Fish Length ◽  
Freshwater Crayfish ◽  
South Wales

The freshwater crayfish C. destructor was a major dietary item for brown trout, Salmo trutta L., and rainbow trout, S. gairdneri Richardson, in Lake Eucumbene, New South Wales. The incidence of crayfish in the diet increased, particularly in brown trout, over the period 1972-1977. The proportion of the trout's diet comprising C. destructor increased with length of brown trout but not with length of rainbow trout. The size of crayfish ingested was postively correlated with fish length for both species of trout, although rainbow trout tended to ingest smaller crayfish than brown trout of equivalent size. Analysis of the crayfish's diet revealed predominantly plant material. Spawning by the crayfish was apparently confined to the period December-April. The abundance of C. destructor in Lake Eucumbene was apparently low until about 1970 but increased between 1972-1977. A decline in the average size of brown and rainbow trout in the angler catch occurred from 1959-1960 until 1977-1978. Hypotheses are suggested for the increase of the crayfish population since impoundment of the lake (1957). Factors considered include predation by trout and the biology of the crayfish, particularly related to its occurrence in this lake, which has fluctuating water levels and a short season suitable for growth and spawning.

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.

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