Reducing the mortality of discarded undersize sand whiting Sillago ciliata in an estuarine seine fishery

2000 ◽  
Vol 51 (8) ◽  
pp. 749 ◽  
Author(s):  
Steven J. Kennelly ◽  
Charles A. Gray
Keyword(s):  
Field Experiment ◽  
Laboratory Experiment ◽  
New South ◽  
New South Wales ◽  
Mesh Size ◽  
Beach Seine ◽  
South Wales ◽  
Large Numbers ◽  
Significant Mortality

A field experiment was done to determine the effects of mesh size in the bunt and codend of an estuarine beach-seine net on the meshing (gilling) and discarding of undersize sand whiting Sillago ciliata (Sillaginidae). Four mesh sizes were examined: 45 mm, 50 mm, 57 mm and 64 mm, in an alternate-haul experiment in the Clarence River, New South Wales, Australia. A laboratory experiment was also done to determine the mortality of sand whiting after becoming meshed in seine nets. The currently allowed mesh size (50 mm) catches a large proportion of undersize sand whiting that become meshed in the netting and are subsequently discarded. The laboratory experiment showed that ~40% of these fish may die within a few weeks whereas no unmeshed fish die. In contrast, the 57 mm mesh size meshed few undersize sand whiting yet retained almost the same number of legal-sized fish as the 50 mm mesh. Hence, the maximum mesh size allowed in the bunts of nets used in this fishery should be raised to 57 mm to allow the escape of large numbers of undersize sand whiting that are currently being caught, meshed and discarded in a condition that leads to significant mortality.

Effects of an increase in mesh size on the catches of fish trawls off New South Wales, Australia

1995 ◽  
Vol 46 (4) ◽  
pp. 745 ◽  
Author(s):  
MK Broadhurst ◽  
SJ Kennelly
Keyword(s):  
New South ◽  
New South Wales ◽  
Mesh Size ◽  
The Body ◽  
South Wales ◽  
Large Numbers ◽  
By Catch ◽  
Species Specific ◽  
Trawl Fisheries ◽  
Future Management

In response to claims that fish trawls off New South Wales, Australia, caught excessive quantities of under-size fish, the catches of finfish by a conventional fish trawl (constructed of 90-mm mesh in the body) were compared with those by a fish trawl constructed of 100-mm mesh in the body. Catches by the 100-mm trawl showed a 27% reduction in all by-catch and a 28% reduction in the numbers of retained tiger flathead, compared with catches by the conventional trawl. The 100-mm trawl also showed a 48% and 47% reduction in the numbers and weights respectively of discarded tiger flathead and a 57% and 63% reduction in the numbers and weights respectively of discarded rubberlip morwong. For john dory, however, at a particular locality where large numbers occurred, the 100-mm trawl caught significantly more fish than did the conventional trawl (a mean increase in weight of 66%). There is a need to determine species-specific mesh selectivities and to study the behaviour of fish in trawls. The importance of the results for the future management and operational efficiency of trawl fisheries is discussed.

Prehistoric aboriginal occupation of the rangelands: Interpreting the surface archaeological record of far western New South Wales, Australia.

2000 ◽  
Vol 22 (1) ◽  
pp. 44 ◽  
Author(s):  
SJ Holdaway ◽  
PC Fanning ◽  
DC Witter
Keyword(s):  
Arid Regions ◽  
Aboriginal People ◽  
New South ◽  
New South Wales ◽  
Landscape Archaeology ◽  
South Wales ◽  
Large Numbers ◽  
Different Parts ◽  
Stone Artefact

Recent erosion in arid regions of western NSW has exposed large areas that are scattered with stone artefacts manufactured by Aboriginal people in prehistory. These exposures offer an opportunity for archaeologists to study the artefacts abandoned by Aboriginal people through time and to compare those artefacts that accumulate in different parts of the landscape. To reconstruct the nature of prehistoric behaviour in the rangelands, two approaches are needed. First, the geomorphological context of the artefacts needs to be considered since exposure of the artefacts is a function of landscape history. Second, large areas (measured in thousands of square metres) and large numbers of artefacts need to be considered if patterns reflecting long-term abandonment behaviour by Aboriginal people are to be identified. This paper reports on the Western New South Wales Archaeological Program (WNSWAP) which was initiated in 1995 to study surface archaeology in the rangelands. Geomorphological studies are combined with artefact analysis using geographic information system software to investigate Aboriginal stone artefact scatters and associated features such as heat retainer hearths, in a landscape context. Results suggest that apparently random scatters of stone artefacts are in fact patterned in ways which inform on prehistoric Aboriginal settlement of the rangelands. Key words: Aboriginal stone artefacts; rangelands; landscape archaeology; geomorphology; GIs

Variations in sex, length and age compositions of commercial catches of Platycephalus fuscus (Pisces : Platycephalidae) in New South Wales, Australia

2002 ◽  
Vol 53 (7) ◽  
pp. 1091 ◽  
Author(s):  
C. A. Gray ◽  
V. J. Gale ◽  
S. L. Stringfellow ◽  
L. P. Raines
Keyword(s):  
Average Length ◽  
New South ◽  
New South Wales ◽  
Total Mortality ◽  
Mesh Size ◽  
Growth Zone ◽  
Male Fish ◽  
Age Composition ◽  
South Wales ◽  
By Catch

Commercial landings of dusky flathead (Platycephalus fuscus) from four estuaries in New South Wales (NSW), Australia, were sampled for data on sex, length and age composition between February and July each year for 2–3 years between 1995 and 1997. Landings primarily contained female fish, ranging from 55% to 93% by number for different estuaries. Flathead sampled in commercial catches ranged from 30 cm to 96 cm total length (TL), but the majority were 33–50 cm TL. Fish >40 cm TL were primarily female and male fish >45 cm TL were uncommon. The length composition of catches differed between gillnets of different mesh sizes, with the average length of fish being least in the smallest allowed mesh size of 70 mm. Fish were aged by otolith interpretation and the analysis of marginal increments indicated that one opaque and one translucent growth zone was formed each year; the opaque zone being deposited in June–August (winter) and first observed in September–October (spring). Commercial landings included fish aged 2–11+ years, but fish aged 2–4+ years dominated landings in all estuaries. The total mortality of dusky flathead in each estuary was estimated by catch curve analysis and was relatively high, ranging from 0.45 to 1.64. The data indicate that dusky flathead may be heavily exploited in NSW.

scholarly journals Overwintering of Clover Nodules in Alpine Conditions

1963 ◽  
Vol 16 (4) ◽  
pp. 920 ◽  
Author(s):  
FJ Bergersen ◽  
FW Hely ◽  
AB Costin
Keyword(s):  
Soil Conservation ◽  
New South ◽  
New South Wales ◽  
Nodule Formation ◽  
Nodule Bacteria ◽  
Trifolium Ambiguum ◽  
South Wales ◽  
Large Numbers ◽  
Complete Fertilizer

As part of a programme investigating soil conservation in the Snowy Mountains area of New South Wales, trials were conducted in which seedlings of Trifolium ambiguum M. Bieb. and T. repens L. (Ladino clover) were planted in the spring of 1960 in eroded areas on Carruthers Peak adjacent to Mt. Kosciusko (lat. 36� 24'S., long. 14So IS'E.) at an elevation of about 7000 ft. Seedlings were raised in seed boxes of soil which had been massively inoculated with appropriate strains of nodule bacteria. Effectively nodulated seedlings were transplanted into peat cups filled with soil. This step was necessary because of the extreme host variation with respect to nodule formation and effectiveness in T. ambiguum (Hely 1957, 1963). The cups were planted intact together with a complete fertilizer mixture; at that stage all plants were well nodulated and the soil in the cups contained large numbers of nodule bacteria.

scholarly journals Developing a beam trawl for sampling estuarine fish and crustaceans: assessment of a codend cover and effects of different sizes of mesh in the body and codend

2008 ◽  
Vol 65 (4) ◽  
pp. 687-696 ◽  
Author(s):  
Douglas Rotherham ◽  
Matt K. Broadhurst ◽  
Charles A. Gray ◽  
Daniel D. Johnson
Keyword(s):  
Experimental Approach ◽  
New South ◽  
New South Wales ◽  
Mesh Size ◽  
The Body ◽  
Estuarine Fish ◽  
Beam Trawl ◽  
South Wales ◽  
The Mean ◽  
Selection Of

Abstract Rotherham, D., Broadhurst, M. K., Gray, C. A., and Johnson, D. D. 2008. Developing a beam trawl for sampling estuarine fish and crustaceans: assessment of a codend cover and effects of different sizes of mesh in the body and codend. – ICES Journal of Marine Science, 65: 687–696. An experiment was carried out in the Clarence River (New South Wales, Australia) to test the hypotheses that fish and crustacean catches in an experimental beam trawl were affected by a codend cover and the sizes of mesh in the body and codend. The cover had no obvious effects on the catches retained in the codend. Similarly, in comparisons between trawl bodies made from 26- and 41-mm diamond-shaped mesh, there were no differences in the assemblages of fish caught, or in the mean numbers entering the codends. For one species of fish (Acanthopagrus australis), however, there were differences in the proportions caught between the trawl bodies across different size classes. There was also some evidence to suggest that mesh size in the body of the trawl influenced the size selection of school prawns (Metapenaeus macleayi). For most finfish, there were no differences in catches between codends made from 20-mm and from 29-mm mesh hung on the bar (i.e. square-shaped mesh). In contrast, mesh size in the codend was important for the size selectivity of school prawns, with smaller carapace lengths at 50% retention in the 20-mm codend. We conclude that use of a 41-mm mesh in the body and a 20-mm square mesh in the codend of the beam trawl would be appropriate for future sampling with this gear in estuaries of New South Wales. A similar experimental approach to ours is needed in adapting the beam trawl to estuaries in other parts of the world, or in developing other types of research trawl.

Energy Reserves, Reproductive Status and Population Biology of Overwintering Biprorulus-Bibax (Hemiptera, Pentatomidae) in Southern New-South-Wales Citrus Groves

1990 ◽  
Vol 38 (4) ◽  
pp. 415 ◽  
Author(s):  
DG James
Keyword(s):  
Population Biology ◽  
New South ◽  
New South Wales ◽  
Reproductive Status ◽  
Energy Reserves ◽  
Citrus Groves ◽  
South Wales ◽  
Behavioural Strategy ◽  
Large Numbers ◽  
Orange Trees

Information is presented on energy reserves, reproductive status and population biology of over- wintering Biprorulus bibax (Breddin) in southern New South Wales citrus groves. Large numbers of adult bugs overwintered in clusters on orange trees adjacent to a lemon grove at Cudgel in the Murrumbidgee Irrigation Area (M.I.A.). Clusters of up to 50 tightly packed bugs were found on single trees, and dispersed into the adjacent lemons in early October. Clustering was observed on all citrus except lemon. Overwintering bugs were non-reproductive. Individuals obtained from overwintering clusters at Dareton in Sunraysia were larger, heavier and contained greater lipid reserves than bugs which overwintered alone. These differences did not occur in cluster and non-cluster bugs from the M.I.A. Bugs overwintering on lemons in the M.I.A. weighed less and contained lower reserves of lipid than did individuals which overwintered on orange, mandarin and grapefruit. Lipid reserves of B. bibax were not greatly depleted during overwintering. Overwintering in clusters on citrus hosts other than lemon appears to be an important and successful behavioural strategy for B. bibax in commercial citrus groves in southern New South Wales.

Structure of a fish community in a temperate tidal mangrove creek in Botany Bay, New South Wales

1984 ◽  
Vol 35 (1) ◽  
pp. 33 ◽  
Author(s):  
JD Bell ◽  
DA Pollard ◽  
JJ Burchmore ◽  
BC Pease ◽  
MJ Middleton
Keyword(s):  
Fish Community ◽  
New South ◽  
New South Wales ◽  
Large Species ◽  
Resident Species ◽  
Marine Habitats ◽  
Mangrove Creek ◽  
South Wales ◽  
Large Numbers ◽  
Permanent Residents

The fish assemblage in the lower reaches of a temperate tidal mangrove creek entering Botany Bay near Sydney, New South Wales, was sampled using rotenone every second month between December 1977 and October 1980. Almost 17 000 fish (weight ~ 115 kg), belonging to 46 species and 24 families, were collected. Six species dominated the assemblage and another four were relatively common. Fourteen species, including four of the above, were economically important. These fishes made up 38% of individuals and 32% of biomass and were represented only by small juveniles. Nineteen species (41%) were temporary residents; these mainly comprised juveniles of large species that live elsewhere as adults. Fifteen species (33%), most of which only attain a small size (< 100 mm), were assumed to be permanent residents. The remaining 12 species (26%) occurred in only one sample and were, therefore, classified as rare. The diversity (HI) and evenness (J') of the fish community were low and showed little seasonality because a few species dominated the assemblage on an irregular basis. Numbers of species and of individuals varied seasonally and were significantly correlated. Peaks in these parameters lagged behind those in water temperature by 4 months and were largely the result of the relatively restricted recruitment periods of several abundant temporary resident species. The large numbers of juveniles and small species in the mangrove creek habitat were attributed to the availability of suitable shelter and food for such small fishes. Concerted use of the mangrove habitat by several abundant temporary resident species during the same general period each year appeared to be facilitated by the occupation of otherwise vacant feeding niches and some staggering of their peak recruitment periods. Exclusive use of this habitat by small juveniles of several species in Botany Bay confirms that mangrove habitats in temperate Australia, like some of those studied in tropical and subtropical regions, are important nursery areas for fishes inhabiting adjacent estuarine and inshore marine habitats as adults.

Observations on the Fish Fauna below Tallowa Dam (Shoalhaven River, New South Wales) during River Flow Stoppages

1978 ◽  
Vol 29 (4) ◽  
pp. 543 ◽  
Author(s):  
KA Bishop ◽  
JD Bell
Keyword(s):  
Endangered Species ◽  
River Flow ◽  
New South ◽  
New South Wales ◽  
Fish Fauna ◽  
Careful Consideration ◽  
Construction Work ◽  
South Wales ◽  
Large Numbers ◽  
Australian Grayling

Some observations on the consequences of construction work at Tallowa Dam (Shoalhaven River, New South Wales) on the fish fauna below the dam are described. In total 17 species of freshwater fish were collected on four occasions between 29 November and 22 December 1976 when water flow was terminated for short periods below the dam wall. Large numbers of individuals belonging to several fish species died on each occasion, including 312 Australian grayling, Prototroctes maraena (an 'endangered' species), on 29 November. It is suggested that water resources authorities should give careful consideration to the ecological effects of constructing and maintaining impound- ments on downstream fish communities.

The incidence of Heliothis armigera (Hübner) and H. punctigera Wallengren (Lepidoptera: Noctuidae) on cotton and other host-plants in the Namoi Valley of New South Wales

1980 ◽  
Vol 70 (1) ◽  
pp. 113-131 ◽  
Author(s):  
K. G. Wardhaugh ◽  
P. M Room ◽  
L. R Greenup
Keyword(s):  
Host Plants ◽  
New South ◽  
New South Wales ◽  
Light Trap ◽  
Heliothis Armigera ◽  
South Wales ◽  
Large Numbers ◽  
Resident Populations ◽  
Successive Generations ◽  
Lepidoptera Noctuidae

AbstractFour years of light-trap and crop survey data from the Namoi Valley of New South Wales are presented for Heliothis armigera (Hb.) and H. punctigera Wllgr. These suggest there are four generations a year. The associated seasonal sequence of major host-plants supporting successive generations, appeared to be: H. armigera—wheat; pre-flowering cotton; flowering cotton and sorghum; sorghum, flowering cotton and sunflowers; and H. punctigera—lucerne, linseed and medics; pre-flowering cotton; flowering cotton, sunflowers and soyabeans; lucerne, linseed and medics; pre-flowering cotton. On host-plants common to both species, a change in dominance from H. punctigera to H. armigera occured as each summer progressed. Suggested causes are: seasonal changes in the availability of host-plants, favouring H. armigera over H. punctigera; insecticide resistance in H. armigera; and the competitive superiority of H. armigera. Large numbers of H. armigera in cotton appeared to be related to: warm springs, which favoured moth emergence during the period of wheat anthesis; the incomplete control of infestations within cotton itself, leading to the development of resident populations; and the influx of moths from other host-plants, especially sorghum, during the latter half of the season.

Effect of resident vegetation on establishment of surface sown pasture species at Glen Innes, New South Wales

1978 ◽  
Vol 18 (92) ◽  
pp. 411
Author(s):  
PM Dowling
Keyword(s):  
Field Experiment ◽  
Festuca Arundinacea ◽  
New South ◽  
New South Wales ◽  
Trifolium Subterraneum ◽  
Quadratic Equation ◽  
Vegetative Cover ◽  
South Wales ◽  
Native Grassland ◽  
The Relationship

The influence of resident vegetative cover on the establishment of surface sown seed was determined in a field experiment at Glen Innes, New South Wales. Seed was sown on 25 occasions over a period of 2 years spanning the period November 1969 to January 1972. Species sown were Phalaris aquatica, Festuca arundinacea, Medicago sativa and Trifolium subterraneum. The relationship between mean per cent establishment and vegetative cover was significant and was described by the quadratic equation y = 0.8064 � 9.8342x - 0.8829x2. Presence of vegetative cover significantly increased mean establishment on 22 occasions. Presence of Sorghum leiocladum plants as a component of the resident vegetation had a larger influence on establishment of surface sown species than Bothriochloa ambigua and Poa sieberana. It was concluded that the best means of obtaining maximum establishment of surface sown pasture species in native grassland areas on the Northern Tablelands of New South Wales was by sowing into vegetative cover (approximately 5000 kg ha-1) and sowing during the period May-July.

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