Life history, food and habitat of southern pygmy perch, Nannoperca australis, in the Macquarie River, Tasmania

1995 ◽  
Vol 46 (8) ◽  
pp. 1159 ◽  
Author(s):  
P Humphries

The reproductive biology, age, growth, food and habitat of Nannoperca australis are described from samples collected from fringing macrophyte beds of the Macquarie River, Tasmania. Comparisons are made with the same species at Narrandera in New South Wales and other nannopercids, mainly in south-western Australia. Nannoperca australis spawned at the end of its first year, predominantly between October and December, inclusive. The peak mean gonadosomatic index of males occurred in August at 8.0 and that of females two months later at 11.5. The largest oocytes, of running-ripe females collected in October and December, were 1.15 mm in diameter. Fecundities ranged from 78 for a 1-year-old 37-mm fish to 679 for a 2-year-old 63-mm fish. Spawning is presumed to occur in the macrophyte habitat, since adults did not emigrate from these areas at this time. Otoliths and length-frequency histograms indicated that populations were dominated by 0+ fish. Amphipods and ostracods predominated in the guts of N. australis and prey items were mostly either benthic invertebrates or plant epifauna. Plankton was consumed by small fish in greater quantities than by larger fish, whereas the opposite was true for benthic and epifaunal prey. Fish were virtually always associated with aquatic macrophytes and almost always with shallow, still water.

1979 ◽  
Vol 7 (5) ◽  
pp. 29-32
Author(s):  

The New South Wales Aboriginal Education Consultative Group feels that more emphasis needs to be placed on the training of teachers in regards to Aboriginal education.Many first year teachers are sent to country areas with a relatively high percentage of Aboriginal students. In the main, these teachers have had little or no contact with Aboriginal children or parents.


1987 ◽  
Vol 14 (2) ◽  
pp. 163 ◽  
Author(s):  
D. Lunney ◽  
B. Cullis ◽  
P. Eby

This study of the effects of logging on small mammals in Mumbulla State Forest on the south coast of New South Wales included the effects of a fire in November 1980 and a drought throughout the study period from June 1980 to June 1983. Rattus fuscipes was sensitive to change: logging had a significant impact on its numbers, response to ground cover, and recapture rate; fire had a more severe effect, and drought retarded the post-fire recovery of the population. The three species of dasyurid marsupials differed markedly in their response to ground cover, canopy cover, logging and fire. Antechinus stuartii was distributed evenly through all habitats and was not affected by logging, but fire had an immediate and adverse effect which was sustained by the intense drought. A. swainsonii markedly preferred the regenerating forest, and was not seen again after the fire, the failure of the population being attributed to its dependence on dense ground cover. Sminthopsis leucopus was found in low numbers, appeared to prefer forest with sparse ground cover, and showed no immediate response to logging or fire; its disappearance by the third year post-fire suggests that regenerating forest is inimical to the survival of this species. Mus musculus showed no response to logging. In the first year following the fire its numbers were still very low, but in the next year there was a short-lived plague which coincided with the only respite in the 3-year drought and, importantly, occurred in the intensely burnt parts of the forest. The options for managing this forest for the conservation of small mammals include minimising fire, retaining unlogged forest, extending the time over which alternate coupes are logged and minimising disturbance from heavy machinery.


1957 ◽  
Vol 8 (1) ◽  
pp. 29 ◽  
Author(s):  
M Blackburn

The diet of surface-swimming Australian barracouta was studied from over 10,000 stomachs. The principal prey organisms in Bass Strait are the euphausiid Nyctiphanes australis Sars, the anchovy Engraulis australis (White), and young barracouta, in that order; and in eastern Tasmania Nyctiphanes, Engraulis, and the sprat Clupea bassensis McCulloch, in that order. The pilchard Sardinops neopilchardus (Steindachner) is not an important item of the diet in these regions although it is so in New South Wales, South Australia, and Western Australia. The jack mackerel Trachurus declivis Jenyns is a significant item in eastern Tasmania and New South Wales but not in Bass Strait. These and other features of the fish diet of the barracouta reflect actual availability of the various small fish species in the waters. Barracouta eat Nyctiphanes by herding them into dense masses (or finding them already concentrated) and swallowing them. The movements of the anchovy make it unavailable to Bass Strait and eastern Tasmanian barracouta for much of the summer and autumn period, when the barracouta are thus dependent upon Nyctiphanes for the bulk of their food. A close positive relationship between the availability of barracouta and Nyctiphanes might therefore be expected at those seasons. There is evidence of such a relationship between mean availability (catch per boat-month) of barracouta and mean percentage of barracouta stomachs containing Nyctiphanes, at those seasons, from year to year. For southern Victorian coastal waters both show a downward trend from 1948-49 to 1950-51 and then an upward trend to 1953-54; for eastern Tasmania both show a downward trend (for autumn only) from 1949-50 through 1952-53. The records of catch per boat-month furnish independent evidence that the main variations in this index were effects of availability (population distribution or behaviour) rather than abundance (population size), at least for southern Victoria. It is therefore considered that when scarcity of barracouta occurs in summer and autumn in the coastal fishing areas it may be due to scarcity of Nyctiphanes, forcing the fish to go offshore for this food which is known to be available there. This would take the fish out of range of the fishermen.


2020 ◽  
Author(s):  
John Nell

Abstract The 120-year-old Sydney rock oyster industry in New South Wales (NSW) and southern Queensland is one of the oldest aquaculture industries in Australia. The industry has been forced to adapt to competition from other species, tighter harvesting and oyster storage and handling requirements as well as eroding profit margins. Recent changes in farming practices include the move away from stick culture to single seed culture, as the half-shell market demands a more uniformly shaped oyster. When selective breeding demonstrated that it could reduce time to market (50 g whole weight) by nearly a year out of an industry average of 3.5 years, the industry wanted to try hatchery technology. Although the industry had never used hatchery technology before, it purchased 10 million spat or 8% of its annual spat requirement from hatcheries in 2003-2004, the first year that they were made available to farmers. The industry also embraced the Australian Shellfish Quality Assurance Program, which requires that shellfish harvest areas be classified on the basis of a sanitary survey and the results of an ongoing strategic water-sampling programme. This programme ensures product safety for the consumers and helps to provide the industry with a long-term future.


2005 ◽  
Vol 29 (5) ◽  
pp. 429-435 ◽  
Author(s):  
Patricia Kenny ◽  
Emily Lancsar ◽  
Jane Hall ◽  
Madeleine King ◽  
Meredyth Chaplin

1992 ◽  
Vol 43 (5) ◽  
pp. 1189 ◽  
Author(s):  
DG Worthington ◽  
DJ Ferrell ◽  
SE NcNeill ◽  
JD Bell

Populations of four species of juvenile fish- Rhabdosargus sarba, Acanthopagrus australis, Achoerodus viridis and Girella tricuspidata-were sampled from a seagrass bed in Botany Bay, New South Wales. Fish were collected eight times between 22 March 1990 and 22 February 1991, using a small seine-net. Growth rates were calculated from the progression of cohorts in length-frequency distributions. Cohorts of R. sarba, A. australis and A. viridis grew most slowly during winter (0.02, 0.04 and 0.21 mm day-1, respectively); growth then increased, peaking just prior to the loss of the cohort from the habitat (0.3 1, 0.24 and 0.39 mm day-1). Populations of R. sarba, A. australis and A. viridis were comprised of one or two cohorts that remained in the habitat for at least 3-4 months. Conversely, up to seven cohorts of G. tricuspidata were found between October and February, and most cohorts did not remain in the habitat for more than 2 months. As a result, there were only two confident estimates of growth for G. tricuspidata: 0.23 mm day-1 between October and November, and 0.34 mm day-1 between January and February. Individuals of each species were also kept in a flow-through 4000-L tank of sea water. Growth of cohorts of fish kept in the tank was very similar to that found in natural populations during the same time period. The rates of recruitment and loss of cohorts from seagrass can be rapid and these factors must be considered in designing a sampling programme to assess growth by analysis of length-frequency distributions.


1998 ◽  
Vol 20 (2) ◽  
pp. 302
Author(s):  
D. Goldney

A long-term mark-recapture program has been carried out on the Duckmaloi Weir (near Oberon, New south Wales) and associated river over the period 1986 to the present. The pipehead weir creates a long shallow ·pool' about 2.5 ha in area, ideal for gill-netting platypuses. One hundred and eighty-two (182) individual animals have been captured in excess of 500 times. The majority of animals have been captured in the weir pool. A very dynamic situation exists with new adults and juveniles being captured on a regular basis and conversely captured animals "disappearing" on a regular basis from the system. Some individuals exhibit both transience and site attachment characteristics. However, relatively few animals remain site attached for long periods of time. Sixty nine percent of individuals are captured two or fewer times. Band loss cannot account for this phenomenon. Of the captured animals, 11.3% have been caught more than 5 times. The sex ratio of the population favours females in first capture adults (1:1.72) but males in first capture juveniles (1:0.73). Females are more likely to be recaptured than males. The sex ratio of juveniles varies significantly from year to year. The period between recaptures varies greatly and can be up to 6 years. Four animals have been captured over nine years (3 females/1 male) but no animal has been captured every year of the study. Recruitment has occurred at levels able to maintain the current population numbers. Thirty percent of available adults have been found lactating, including second year females. Seventy one percent of first year capture juveniles and 89.9% of first capture adults "disappear" within two years of first capture. Forty two percent of juvenile animals reach adult status before "disappearing".


1967 ◽  
Vol 7 (24) ◽  
pp. 7 ◽  
Author(s):  
P McInnes ◽  
TJ Grainger ◽  
MD Smith

Data are presented on the recovery and reproductive performance of 2 1/2-year-old maiden Merino ewes after a prolonged period of undernutrition. The 217 sheep had been hand-fed on a submaintenance ration in pen feeding trials at Glenfield, New South Wales. During the seven months of the trials they had lost 6 kg (28 to 22 kg) body weight. They were transported to Condobolin in south-western New South Wales, divided into two treatment groups and run on good quality pastures. One group was joined immediately (May 1959) and again ten months later, and the other group was mated after six months at Condobolin (in October 1959) and again 12 months later. The ewes recovered rapidly. The mean weight of both groups had reached 30 kg within six weeks and 40 kg within six months. In the first year 73 of the 100 May-mated ewes bore lambs, but only 38 of these lambs were weaned. Ewes bearing lambs had a higher body weight at the start of joining and gained more during joining than the barren ewes. At the other three joinings (October 1959, May 1960, October 1960) lambing percentage was from 86-89 and weaning percentage from 62-69-both normal for the district. The proportion of twin lambs (3-6 per cent) was low. Wool weight in 1959 was not affected by time of mating or by pregnancy.


1963 ◽  
Vol 3 (10) ◽  
pp. 180 ◽  
Author(s):  
K Spencer

Yield responses d a native pasture on a basaltic soil near Willow Tree, New South Wales, were measured in the second, fourth, and seventh years after the application of several rates of calcium sulphate in the first year. The value of the residues declined sharply at first and then more slowly. Fifty per cent of the potential response by the legumes (the responsive component of the pasture) was achieved by an application of 7lb of sulphur an acre in the first year ; residues from an application of 20 lb of sulphur an acre were required in the second year, and from 48 lb S of sulphur an acre in the fourth year, to obtain the equivalent responses. By the seventh year, effects were too small to allow the derivation of a comparable figure.


Sign in / Sign up

Export Citation Format

Share Document