The New South Wales Trawlfishery: Review of Past Course and Examination of Present Condition

1955 ◽  
Vol 6 (2) ◽  
pp. 165 ◽  
Author(s):  
TW Houston
Keyword(s):  
New South ◽  
New South Wales ◽  
Size Composition ◽  
Fishing Effort ◽  
Present Condition ◽  
Catch Per Unit Effort ◽  
Nineteen Thirties ◽  
Unit Effort ◽  
South Wales ◽  
Post War

The past course of the New South Wales mixed trawlfishery is reviewed mainly on the basis of the available catch and fishing effort statistics. The size composition of tiger flathead landings from 1946-47 to 1953-54, and the age composition for certain post-war years, are analysed in conjunction with catch per unit effort data. The results suggest that 1943-44, 1944-45, 1947-48, and 1948-49 were relatively poor brood years, and 1945-46 and 1946-47 relatively good. The fluctuations in availability of tiger flathead (Neoplatycephalus macrodon (Ogilby) ) are accounted for after making certain valid assumptions. It is considered probable that the unexpectedly low catches of tiger flathead in the immediate post-war years were due to inefficiency of the few steam trawlers then working, and that Danish seiners were unable to exploit fully the available V+ and higher age-group fish. An examination of the present situation indicates that the New South Wales stock of tiger flathead is at a low level and is likely to reach even lower levels in the future if fishing intensity remains as high as in 1953-54. An improvement of the existing catch per unit effort would be expected if fishing intensity was reduced to the level of the middle nineteen-thirties (i.e. approx. 3500 trawler-tons) . Other regulative measures would need to be introduced to bring about an improvement in the annual catch of tiger flathead. These measures should aim at ensuring a more favourable weight-length relation.

scholarly journals Comparative Angler Catches of Australian Bass (Macquaria novemaculeata) in Three Major River Systems in New South Wales, Australia

2005 ◽  
Vol 18 (2) ◽  
Author(s):  
B. VAN DER WALT ◽  
R. A. FARAGHER ◽  
J. HARRIS
Keyword(s):  
Time Series Data ◽  
New South ◽  
New South Wales ◽  
River System ◽  
Size Composition ◽  
Series Data ◽  
Severe Drought ◽  
Catch Per Unit Effort ◽  
South Wales ◽  
Catch Rates

A joint program between New South Wales Fisheries and three fishing clubs was initiated in 1988 with the aim of collecting standardised catch and effort data during biannual fishing competitions on three major rivers in New South Wales. This paper examines the data to determine trends in the catch of the target species, Australian bass (Macquaria novemaculeata) and to evaluate whether the data can be used to assess Australian bass populations over time. Distinct trends in Australian bass mean length in each river system were evident but catch rates were more variable. Median catch per unit effort was similar (mostly between 0.5 and 1.5 Australian bass·h-1 ) in the Nepean and Williams Rivers although catch rates in the Manning River were nearly always zero. There was an increasing trend in the mean length of Australian bass in all three rivers, possibly representing a recovery in fish populations following severe drought from 1979 to 1983. Low or zero catch rates were continually recorded in the Manning River and size composition data indicated a lack of recruitment through most of the study period. The standardised format of the data collection program provided qualitative and reliable time series data allowing the determination of long-term trends in the population structure of Australian bass which can be used for monitoring and management purposes.

Bag Sizes of Waterfowl in New-South-Wales and Their Relation to Antecedent Rainfall

1988 ◽  
Vol 15 (4) ◽  
pp. 459 ◽  
Author(s):  
SV Briggs ◽  
JE Holmes
Keyword(s):  
New South ◽  
New South Wales ◽  
Annual Rainfall ◽  
Catch Per Unit Effort ◽  
Antecedent Rainfall ◽  
Game Species ◽  
Unit Effort ◽  
South Wales ◽  
Black Duck ◽  
Eastern Australia

Bag sizes of game ducks in New South Wales between 1977 and 1984 were compared with antecedent annual rainfall in eastern Australia. Mean bag size is equivalent to 'catch-per-unit-effort', an index of population abundance. Annual rainfall is an index of habitat availability for waterfowl. Bag sizes of Pacific black duck and all game species combined were significantly (P<O.05) related to antecedent rainfall. Rates of increase (computed from annual catch-per-unit-effort) of black duck, maned duck and all species combined were significantly related to rainfall difference between the preceding 2 years. This study indicates that prior rainfall is a useful predictor of duck numbers in New South Wales.

The New South Wales Tiger Flathead Neoplatycephalus macrodon (Ogilby). II. The Age Compositon of the Commercial Catch, Overfishing of the Stocks, and Suggested Conservation

1952 ◽  
Vol 3 (1) ◽  
pp. 1 ◽  
Author(s):  
WS Fairbridge
Keyword(s):  
New South ◽  
Age Groups ◽  
Fishing Ground ◽  
Alternative Measure ◽  
Age Group ◽  
Catch Per Unit Effort ◽  
Commercial Catch ◽  
Conservation Measure ◽  
South Wales ◽  
Post War

The commercial flathead catch is analysed into its component age-groups. The results are expressed in numbers and weight of each age-group caught in each month. The results indicate an absence of natural fluctuations in abundance of the year-groups during the series of years covered. The post-war decline in the catch of flathead is discussed in the light of this analysis. The catch has fallen from 5,700,000 lb. in 1944–45 to 2,100,000 lb. in 1948–49. The catch of flathead for a period between the wars is estimated at over 10,000,000 lb. per year. The stock of flathead has thus shown a failure to recover during the war-time rest, as well as a sudden fall with the inception of heavy fishing of recent years. Possible reasons for these changes in the flathead stock are discussed. It is suggested that the numbers of recruits are limited by the numbers of spawning adults. The results obtained from this work are fuller, but in entire agreement with those of the earlier paper on the trawlfishery as a xvliole. The adoption of conservation measures is urged. The trawlfishery is now dependent on two hitherto discarded species of poorer quality than the flathead, and the better of these is already showing a reduced catch per unit effort of fishing. The most important conservation measure is that suggested in the earlier paper — a reduction of the fleet to the equivalent of 13 trawlers. It is regarded as probable that if this step is not taken, the annual trawlfish catch will continue to decline. Closure of the Botany fishing ground is suggested as a further, but not an alternative, measure.

Decadal trends in shark catches and effort from the New South Wales, Australia, Shark Meshing Program 1950 - 2010

2011 ◽  
Vol 62 (6) ◽  
pp. 676 ◽  
Author(s):  
D. D. Reid ◽  
W. D. Robbins ◽  
V. M. Peddemors
Keyword(s):  
New South ◽  
New South Wales ◽  
Temporal Trends ◽  
Catch Per Unit Effort ◽  
Galeocerdo Cuvier ◽  
South Wales ◽  
Before And After ◽  
Large Animals ◽  
Size And Sex Composition ◽  
Over Time

The New South Wales (NSW) government has operated a program of netting beaches for the protection of swimmers and surfers against shark attack since 1937 in Sydney, and since 1949 in Newcastle and Wollongong. The scope and directives of the Shark Meshing Program have remained constant since its inception, with operational modifications in net specifications in 1972, changes in spatial deployment in 1972, 1987 and 1992, and the elimination of winter netting since 1989. This markedly increased meshing effort in 1972, and again in 1987. In the present study, we examine the trends in catch and effort for the period from 1950–1951 to 2009–2010 over this 200-km section of the NSW coast. Significant temporal trends in species, size and sex composition are described herein. Catches were consistently dominated by three shark taxa, hammerhead sharks (Sphyrna spp.), whaler sharks (Carcharhinus spp.) and Australian angel sharks (Squatina australis), although their relative contributions to catches varied over time. Catch per unit effort has significantly declined for five of the most abundant shark taxa over the study period, increasing only for a single taxon, the sevengill shark (Notorynchus cepedianus). Catches of larger, potentially dangerous white sharks (Carcharodon carcharias) and tiger sharks (Galeocerdo cuvier) saw fewer large animals being caught over time. This pattern was not observed across other taxa. Four different monthly trends were observed in landings of the most abundant eight taxa, reflecting differences in the biology of the catch species. The current study also provides useful information on catches and sizes of grey nurse (Carcharias taurus) and white sharks before and after their protection in NSW waters in 1984 and 1998, respectively.

An assessment of pedoturbation by two species of mound-building ants, Camponotus intrepidus (Kirby) and Iridomyrmex purpureus (F. Smith)

Soil Research ◽  
1985 ◽  
Vol 23 (1) ◽  
pp. 95 ◽  
Author(s):  
JA Cowan ◽  
GS Humphreys ◽  
PB Mitchell ◽  
CL Murphy
Keyword(s):  
Impact Energy ◽  
Organic Material ◽  
Size Structure ◽  
New South ◽  
New South Wales ◽  
Size Composition ◽  
Soil Mixing ◽  
South Wales ◽  
Erosion Protection ◽  
Raindrop Impact

Details of the size, structure and occurrence of Carnponotus intrepidus nests and the size, composition and source of the mound cover on Iridomyrmex purpureus nests are reported from several areas of eastern New South Wales. Both species are common, and construct large mounds of mixed topsoil and subsoil with surface covers, which appear to protect the mound from rainsplash erosion. Camponotus thatches the mound with charcoal, leaves and twigs; Iridomyrmex covers the mound in granules of inorganic or organic material that are sufficiently large to absorb most raindrop impact energy. This material is collected from the surface and carried 10-15 m to the nest. Rainsplash erosion protection is probably a factor contributing to nest longevity, which may be as much as 100 years for Iridomyrmex. It is concluded that, despite the impressive size of the nests and the selective use of materials, neither species is very significant in terms of soil mixing when compared with the smaller, more common ant Aphaenogaster longiceps.

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