Feeding ecology of the temperate marine fish Achoerodus viridis (Labridae): Size, seasonal and site-specific differences

1995 ◽  
Vol 46 (7) ◽  
pp. 1009 ◽  
Author(s):  
BM Gillanders
Keyword(s):  
Feeding Ecology ◽  
Feeding Rate ◽  
New South ◽  
Juvenile Fish ◽  
Rocky Reef ◽  
Rocky Reefs ◽  
South Wales ◽  
Labrid Fish ◽  
Harpacticoid Copepods ◽  
Rocky Reef Fish

Fish were collected from localities in the Sydney region, New South Wales, Australia, from March 1991 to September 1993. Achoerodus viridis is a benthic carnivore and consumes a wide variety of prey items. Size-specific differences in diet were found. The diet of recruits (17-26 mm SL) collected in seagrass environments was dominated by tanaids, whereas that of rocky reef recruits was dominated by harpacticoid copepods. The diet of rocky reef fish then shifted to gammarid amphipods and other crustaceans (fish 50-150 mm SL) and to mussels and urchins (fish >300 mm SL). Juvenile fish on rocky reefs (450 mm SL) foraged in shallow fringing habitat, whereas adult fish (>200 mm SL) foraged in deeper turf and barrens habitats, reflecting the depth distribution of the species. Feeding rate of larger fish tended to be less than that of smaller fish. Variations in diet and feeding rate were also detected over the year but the patterns were not consistent between years. Among sites, there were differences in diet but these were not related to the position of sites inside an estuary or on the open coast. The results of this study provide information on the feeding ecology of a large labrid fish; this information will aid in understanding the population dynamics of the species.

Growth of four species of juvenile fish associated with the Seagrass Zostera capricorni, in Botany Bay, NSW

1992 ◽  
Vol 43 (5) ◽  
pp. 1189 ◽  
Author(s):  
DG Worthington ◽  
DJ Ferrell ◽  
SE NcNeill ◽  
JD Bell
Keyword(s):  
Sea Water ◽  
New South ◽  
Juvenile Fish ◽  
Natural Populations ◽  
Length Frequency ◽  
Frequency Distributions ◽  
South Wales ◽  
Time Period ◽  
Flow Through ◽  
Sampling Programme

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.

Range and habitat associations of the native macroalga Caulerpa filiformis in New South Wales, Australia

2015 ◽  
Vol 66 (11) ◽  
pp. 1018 ◽  
Author(s):  
Tim M. Glasby ◽  
Peter. T. Gibson ◽  
Gregory West ◽  
Peter Davies ◽  
Sofietje Voerman
Keyword(s):  
New South ◽  
New South Wales ◽  
Habitat Associations ◽  
Disjunct Distribution ◽  
Species Introduction ◽  
Isolated Populations ◽  
Rocky Reefs ◽  
South Wales ◽  
Green Seaweed ◽  
Natural Range

Caulerpa filiformis is a green seaweed found in New South Wales (NSW, Australia), South Africa, Mozambique and Peru. It has been suggested that the abundance of the species has increased in NSW over recent decades. Extensive aerial and diver surveys identified a 500-km northerly extension to the range of C. filiformis in NSW (to 28°21′S) compared with previous records. The alga has a disjunct distribution with small isolated populations around rocky headlands in far northern NSW, but then no apparent populations for 350km southwards. The far northern populations could be the result of recent human-mediated transport (a species introduction), or were simply not detected previously. The increased distribution around the previous northerly limit is likely a natural range expansion. The distribution of C. filiformis in NSW and globally seems confined to a temperature range of ~16–23°C. We found no relationship between abundance of C. filiformis and human population or oceanic chlorophyll-a (a surrogate for nutrient availability). We demonstrate that C. filiformis is predominately subtidal, being found along sections of coastline where there is a mixture of rocky reefs and beaches. It is argued that sand movement may have facilitated increases in abundance of C. filiformis.

scholarly journals Humans as predators on rocky reefs in New South Wales, Australia

1991 ◽  
Vol 72 ◽  
pp. 1-14 ◽  
Author(s):  
MJ Kingsford ◽  
AJ Underwood ◽  
SJ Kennelly
Keyword(s):  
New South ◽  
New South Wales ◽  
Rocky Reefs ◽  
South Wales

Reproductive cycles in the eastern subspecies of the Australian salmon, Arripis trutta marginata (Cuvier & Valenciennes)

1977 ◽  
Vol 28 (3) ◽  
pp. 287 ◽  
Author(s):  
CA Stanley ◽  
WB Malcolm
Keyword(s):  
Sexual Activity ◽  
New South ◽  
Juvenile Fish ◽  
Gonad Weight ◽  
Spawning Activity ◽  
Similar Work ◽  
South Wales ◽  
Younger Age ◽  
Reproductive Cycles ◽  
Weight Data

To complement similar work carried out on the western subspecies of the Australian salmon (Arripis trutta esper), the known data on the reproductive cycle of the eastern subspecies (A. t. marginata) are summarized. The data (collected between 1961 and 1963) consisted of ovary and testis welghts, fish lengths, oocyte diameters from preserved ovaries, and information from histological material. The gonad weight data were analysed to show increases in ovary and testls weights, which were indicative of sexual activity. Supporting information was extracted from changes in maximum oocyte diameters, and from examination of histological sections. The onset of sexual maturity for juvenile fish in Tasmanian waters occurred at a length of approximately 39 cm (equivalent to the end of the fourth year of life). The corresponding length for the western subspecies is 54 cm (at approximately the same age), and 52-54 cm for New Zealand fish. There was no evidence of spawning activity in Tasmanian waters. Cycles of sexual activity were observed in fish from the Lakes Entrance area of Victoria and the Eden and Bermagul areas of southern New South Wales. Spawning activity was deduced to occur between December and January in the Lakes Entrance area, between January and February in the Eden area, and between November and February in the Bermagui area. Sexual maturation may commence in males at a slightly younger age than in females.

Drifting objects as habitat for pelagic juvenile fish off New South Wales, Australia

2004 ◽  
Vol 55 (7) ◽  
pp. 675 ◽  
Author(s):  
Tim Dempster ◽  
Michael J. Kingsford
Keyword(s):  
New South ◽  
Juvenile Fish ◽  
New South Wales ◽  
Weather Conditions ◽  
Small Fish ◽  
Drift Algae ◽  
Odour Source ◽  
South Wales ◽  
Fish Aggregation ◽  
Drifting Algae

The importance of drifting objects to small juvenile pelagic fish was investigated off the coast of New South Wales, Australia. Distance-related and temporal patterns in the distribution of clumps of drifting algae were investigated with 5000 m2 transects at five distances from shore (0.1, 0.5, 1, 5 and 10 km), two to three times per season for 2 years. Juvenile fish associated with drift algae were collected. Clumps of algae, predominantly Sargassum spp., were most abundant in spring, which coincided with the highest abundance of alga-associated post-flexion juvenile fish. Drift algae were also most abundant close to shore, probably due to the proximity to source and the dominant onshore winds. Fish were quickly attracted to drifting artificial objects (fish aggregation device; FADs), although the magnitude of attraction varied greatly among days. The relative abundance of small fish in open waters available to colonise FADs and differing weather conditions may explain much of this variability. More fish colonised FADs with an odour source than unscented control FADs, indicating small fish may use chemical cues to locate drifting structures. We conclude that juvenile fish actively seek drifting objects as pre-settlement habitat, which may reduce predation and enhance settlement opportunities.

scholarly journals Artificial crevice habitats to assess the biodiversity of vagile macro-cryptofauna of subtidal rocky reefs

2008 ◽  
Vol 59 (8) ◽  
pp. 661 ◽  
Author(s):  
Mateus de A. Baronio ◽  
Daniel J. Bucher
Keyword(s):  
River Discharge ◽  
New South ◽  
Benthic Communities ◽  
East Australian Current ◽  
Kelp Beds ◽  
Rocky Reefs ◽  
South Wales ◽  
Different Seasons ◽  
Differential Exposure ◽  
Subtidal Rocky Reefs

Reef cryptofauna (animals inhabiting cracks and crevices) represent much of a reef’s biodiversity yet are seldom studied owing to their inaccessibility. Subtidal rocky reefs off Brunswick Heads and Byron Bay in northern New South Wales, Australia support benthic communities ranging from coral-dominated offshore reefs to kelp beds of Ecklonia radiata on inshore reefs. It was hypothesised that differential exposure to river discharge and the East Australian Current, as well as proximity to other reef habitats, may produce differences in recruitment and persistence of cryptofauna between superficially similar reefs within a small geographical range. Artificial crevice habitats were deployed at similar depths on three inshore reefs supporting similar Ecklonia densities. Although the species richness of crevice fauna was similar at all reefs, the species composition differed significantly along with the assemblages recruited in different seasons and to different crevice sizes. Neither reef faunas nor that of varying crevice sizes changed consistently with the seasons, yet all crevices appeared equally accessible to colonists. These results demonstrate the potential inadequacy of classifying reef communities for management of regional biodiversity based on the visual dominance of a few species that may not be as sensitive to environmental variables as many of the less obvious taxa.

Feeding Ecology of the Barn Owl, Tyto Alba, in Arid Southern Australia.

1979 ◽  
Vol 6 (2) ◽  
pp. 191 ◽  
Author(s):  
SR Morton ◽  
AA Martin
Keyword(s):  
Feeding Ecology ◽  
New South ◽  
New South Wales ◽  
South Australia ◽  
Barn Owl ◽  
Tyto Alba ◽  
South Wales ◽  
Barn Owls ◽  
The Mean ◽  
Study Sites

In arid parts of Australia the barn owl appears to feed largely on rodents which form irruptions or plagues, i.e. undergo marked changes in abundance. Barn owls became common at the height of an irruption of house mice, Mus musculus, in western New South Wales, but were comparatively scarce after the mice decreased in numbers. There was some evidence that the owls' diet, determined by analysis of pellets, was more varied immediately after the numbers of mice decreased, but its major part still consisted of M. musculus. The mean number of prey units represented in each pellet rose during the irruption and then declined to the original level. At a variety of sites in arid New South Wales and South Australia, barn owls' diet consisted almost entirely of small mammals. The most common prey species were rodents that fluctuate widely in abundance, and the mean amount of prey per pellet differed greatly among the study sites. The feeding ecology of barn owls in arid Australian environments is essentially similar to that described for more mesic habitats; hence, a greatly increased variation in the abundance of mammalian prey has not led to an increase in breadth of food niche.

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