Feeding dynamics, consumption rates and daily ration of longtail tuna (Thunnus tonggol) in Australian waters, with emphasis on the consumption of commercially important prawns

2007 ◽  
Vol 58 (4) ◽  
pp. 376 ◽  
Author(s):  
Shane P. Griffiths ◽  
Gary C. Fry ◽  
Fiona J. Manson ◽  
Richard D. Pillans
Keyword(s):  
Gonad Development ◽  
Reproductive Activity ◽  
Daily Ration ◽  
Feeding Intensity ◽  
Energy Investment ◽  
Trophic Pathways ◽  
Eastern Australia ◽  
Consumption Rates ◽  
Autumn And Winter ◽  
Longtail Tuna

The feeding ecology of longtail tuna was studied in northern and eastern Australia. Diet biomass data were used to estimate daily ration and consumption of individual prey taxa, particularly penaeids targeted by Australia’s valuable Northern Prawn Fishery (NPF). Overall, the 497 stomachs contained 101 prey taxa. In both regions, small pelagic and demersal fishes comprised the majority of the diet biomass. Fish in both regions showed a marked increase in prey diversity, variation in prey composition and stomach fullness index in autumn and winter (March–August). This increase in apparently opportunistic feeding behaviour and feeding intensity showed an inverse relationship with reproductive activity, indicating a possible energy investment for gonad development. Daily ration decreased with increasing fish size, while annual consumption by fish increased with size. Total prey consumption in the Gulf of Carpentaria was estimated at 148178 t year–1. This includes 599 t year-1 of penaeids, equivalent to 11% of the annual NPF catch. This study demonstrated that longtail tuna play an important ecological role in neritic ecosystems. Their interaction with commercial fisheries highlights the need for targeted dietary studies of high order predators to better understand trophic pathways to facilitate ecosystem-based fisheries management.

scholarly journals Influence of environmental variables on the feeding and diet of European hake (Merluccius merluccius) on the Mediterranean Iberian coasts

2004 ◽  
Vol 84 (4) ◽  
pp. 831-835 ◽  
Author(s):  
J.E. Cartes ◽  
J. Rey ◽  
D. Lloris ◽  
L. Gil de Sola
Keyword(s):  
Prey Availability ◽  
Western Mediterranean ◽  
Delayed Response ◽  
Feeding Intensity ◽  
Merluccius Merluccius ◽  
Phytoplankton Pigment ◽  
Consumption Rates ◽  
Wet Weight ◽  
European Hake ◽  
Food Consumed

The feeding intensity and the diet of Merluccius merluccius were studied along a 1000 km latitudinal scale on the coasts of the Iberian Peninsula (western Mediterranean) in spring 2000. Merluccius merluccius was distributed along two bathymetric bands corresponding to the deep continental shelf (between 36 to 148 m), and the upper slope (between 215 to 310 m). At the shelf small crustaceans (mainly euphausiids and mysids) were dominant in the diet while fish (mainly Myctophidae) were the preferred prey on the slope. Feeding intensity of hake was significantly higher in areas with higher hake density suggesting feeding aggregations. Also, feeding intensity was significantly correlated with phytoplankton pigment concentrations (ppc), though only with ppc recorded one month before on the hake sampling stations. This delay between ppc and feeding intensity of hake may be a response to higher prey availability, because most hake prey were pelagic in origin (euphausiids, Clupeiformes) and they may reach high densities after exploiting local phytoplankton blooms. This delayed response seems to have more a local or spotted pattern. During three 8-h sampling cycles food consumed by hake ranged between 1·01 to 5·51% body wet weight (BWW), on average within the range of food consumption rates of other benthopelagic, active swimmer, fish.

Prolactin receptor regulates the seasonal reproduction of striped hamsters

Zygote ◽  
2021 ◽  
pp. 1-8
Author(s):  
Huiliang Xue ◽  
Jinhui Xu ◽  
Ming Wu ◽  
Lei Chen ◽  
Laixiang Xu
Keyword(s):  
Prolactin Receptor ◽  
Expression Patterns ◽  
Reproductive Activity ◽  
Mature Female ◽  
Seasonal Reproduction ◽  
Population Abundance ◽  
Serum Concentrations ◽  
Expression Levels ◽  
Autumn And Winter ◽  
Differential Mrna Expression

Summary In this study, differential mRNA expression patterns of prolactin receptor (PRLR) in the hypothalamus and gonads, and the correlation with follicle stimulating hormone (FSH) and luteinizing hormone (LH) in striped hamster serum from spring, summer, autumn and winter were analyzed. Mature female and male striped hamsters in oestrus were used. Expression levels of PRLR in the hypothalamus, ovaries and testis from the summer and winter individuals were significantly higher compared with levels from the spring and autumn, whereas FSH and LH serum concentrations from summer and winter individuals were significantly lower compared with that from the spring and autumn. PRLR expression levels in hypothalamus, ovaries and testis were negatively correlated with FSH and LH serum concentrations, illustrating that PRLR might negatively regulate seasonal reproductive activity. PRLR expression levels in ovaries and testes were significantly higher compared with levels in the hypothalamus, suggesting that the regulative effects of PRLR in gonads might be significantly higher compared with that in the hypothalamus. Furthermore, PRLR expression levels from the spring, summer, autumn and winter seasons in the hypothalamus and gonads were significantly higher in females compared with levels in males, indicating that the regulative effect of PRLR might be sex dependent. Taken together, this study helps to understand in depth the seasonal regulative reproduction mechanism of striped hamsters to reasonably control population abundance.

scholarly journals Seasonal variability of the composition and structure of parasite communities of red porgy, Pagrus pagrus (Perciformes: Sparidae) off Brazil

2015 ◽  
Vol 52 (3) ◽  
pp. 236-243 ◽  
Author(s):  
I. A. Soares ◽  
J. L. Luque
Keyword(s):  
Rainy Season ◽  
Dominant Species ◽  
Parasite Community ◽  
Reproductive Activity ◽  
Metazoan Parasites ◽  
Parasite Communities ◽  
Four Seasons ◽  
Composition And Structure ◽  
Pagrus Pagrus ◽  
Autumn And Winter

Abstract A study of seasonal variation of metazoan parasite community of Pagrus pagrus was conducted between January and December 2012. Two hundred forty specimens of Pagrus pagrus were collected in four seasons (autumn and winter in dry season and spring and summer in rainy season) from off the state of Rio de Janeiro, Brazil. Twenty one species of metazoan parasites were found, with larvae of Hysterothylacium sp. being the dominant species. The highest values of prevalence and abundance was during the rainy season with peak prevalence of monogeneans and nematodes, period of action of the South Atlantic Central Waters (SACW) and reproductive activity of the host, suggesting that the sasonal variation in the parasites community was influenced for these phenomena.

scholarly journals The relationship between the subtropical ridge and Australian temperatures

2018 ◽  
Vol 68 (1) ◽  
pp. 201
Author(s):  
Acacia Pepler ◽  
Linden Ashcroft ◽  
Blair Trewin
Keyword(s):  
Strong Influence ◽  
Southeast Australia ◽  
Eastern Australia ◽  
Autumn And Winter ◽  
The Relationship ◽  
Subtropical Ridge ◽  
Australian Rainfall

The intensity and latitude of the subtropical ridge over eastern Australia is strongly associated with southeast Australian rainfall, particularly during the cool months of the year. We show that the subtropical ridge also exerts a strong influence on temperatures across much of Australia, with warmer daytime temperatures and more warm extremes across southern Australia when the subtropical ridge is stronger than average, which is largely independent of the relationship between the subtropical ridge and rainfall. A strong subtropical ridge is also linked to warmer than average minimum temperatures over southern Australia throughout much of the year, except from May to August when a strong ridge is associated with cooler mean minimum temperatures and an increased frequency of cool nights. This relationship, and the observed strengthening of the subtropical ridge during autumn and winter in recent decades, can partially explain the weaker warming trends in minimum temperatures in southeast Australia compared to elsewhere in the country over the period 1960-2016.

Faecal steroid analysis and urinary cytology of the squirrel glider (Petaurus norfolcensis)

2006 ◽  
Vol 54 (4) ◽  
pp. 277 ◽  
Author(s):  
Carly Woodd ◽  
Natasha A. Czarny ◽  
Ian M. G. Gunn ◽  
Wayne Sturrock
Keyword(s):  
Post Partum ◽  
Reproductive Activity ◽  
Habitat Destruction ◽  
Urinary Cytology ◽  
Gestational Length ◽  
Non Invasive ◽  
Eastern Australia ◽  
Steroid Analysis ◽  
Squirrel Glider ◽  
Invasive Techniques

Non-invasive techniques were used to investigate the reproductive biology of captive squirrel gliders (Petaurus norfolcensis) for 3 months during the breeding season. The squirrel glider is a medium-sized marsupial glider of eastern Australia and is currently listed as a threatened species as a result of habitat destruction and fragmentation. Urinary cytology was used to determine the timing of oestrus, and the presence of sperm confirmed mating. Progesterone and oestradiol-17β were identified in faecal samples via thin-layer chromatography, and were used to characterise the reproductive cycle. Reproductive activity was observed in three of four females, with births occurring during June and July. A preoestrus increase in faecal oestradiol-17β was detected in a single female, whilst significant increases occurred post partum (±2 days) in two of four females, suggesting that the squirrel glider may undergo a postpartum oestrus. Faecal progesterone profiles showed low concentrations before oestrus and significantly elevated concentrations after oestrus, which were maintained throughout pregnancy. Parturition coincided with a decrease in progesterone concentrations (±1 day). This study successfully used non-invasive monitoring of urinary cytology and faecal steroids to define luteal and gestational length as 16–17 days, a previously unpublished detail.

Seasonal Patterns in Bait Consumption by Feral Pigs (Sus Scrofa) in the Hill Country of South-Eastern Australia.

1993 ◽  
Vol 20 (5) ◽  
pp. 637 ◽  
Author(s):  
JC Mcilroy ◽  
EJ Gifford ◽  
RI Forrester
Keyword(s):  
Sus Scrofa ◽  
National Park ◽  
Seasonal Patterns ◽  
Australian Capital Territory ◽  
Feral Pigs ◽  
Hill Country ◽  
Eastern Australia ◽  
Main Factors ◽  
Autumn And Winter ◽  
The Hill

Both fermenting wheat and bran/pollard pellets were readily accepted as bait throughout the year by feral pigs (Sus scrofa) in Namadgi National Park, Australian Capital Territory. Birds mainly ate wheat bait, particularly during winter. Other animals occasionally fed on both types of bait, mainly during autumn and winter. Covering baits with forest-floor litter did not significantly affect their discovery and consumption by pigs or by other animals. The proximity of the pigs to the bait line and their appetite for bait appeared to be the main factors responsible for seasonal differences in bait consumption. Trail-baiting campaigns against pigs in similar hill country areas are likely to be more effective during late autumn than other seasons because more pigs are likely to be close to the trails then and more quickly find and eat greater quantities of bait.

Population dynamics of Sesarma rectum (Crustacea: Brachyura: Grapsidae) in the Ariquindá River mangrove, north-east of Brazil

2011 ◽  
Vol 91 (7) ◽  
pp. 1395-1401 ◽  
Author(s):  
Daniela da Silva Castiglioni ◽  
Paloma Joana Albuquerque de Oliveira ◽  
Josivan Soares da Silva ◽  
Petrônio Alves Coelho
Keyword(s):  
Sex Ratio ◽  
Sexual Maturity ◽  
Carapace Width ◽  
Reproductive Activity ◽  
Reproductive Period ◽  
Size Class ◽  
Adult Males ◽  
North East ◽  
Class Frequency ◽  
Autumn And Winter

This study was carried out in order to provide basic information on the population ecology of the crab Sesarma rectum in the Ariquindá River mangrove, Tamandaré, State of Pernambuco, Brazil. The population was analysed with regard to the following aspects, in particular: the size-class frequency distribution of carapace width (CW), mean body size (CW) of males and females, morphological sexual maturity, sex-ratio, reproductive period, and recruitment. Samples were collected monthly from April 2008 through to March 2009; the crabs were collected manually, with a capture effort by one person for 30 minutes, during low tide. The specimens obtained were measured for CW, length of the propodus of males, and abdomen width of females; and the sex and ovigerous condition were noted. Altogether, we obtained 511 specimens (132 juvenile and 137 adult males, and 171 juvenile and 71 adult females, of which 32 were ovigerous). The median CW of males (16.15 mm) was significantly larger than that of females (13.82 mm) (P < 0.05). The size at morphological sexual maturity was 15.73 mm in males and 16.71 mm in females. The sex-ratio for the total of specimens analysed was 1.11:1 (male:female) (P > 0.05). The sex-ratio by size-class showed an anomalous pattern, with a greater abundance of males in the larger size-classes. The reproductive period was continuous and the highest frequency of ovigerous females was recorded in the spring and summer. The major pulse of recruitment occurred during autumn and winter, which is related to greater reproductive activity during the warmer months of the year.

Hypogeal fungi in the diet of the long-nosed potoroo (Potorous tridactylus) in mixed-species and regrowth eucalypt forest stands in south-eastern Australia

1993 ◽  
Vol 20 (3) ◽  
pp. 321 ◽  
Author(s):  
AW Claridge ◽  
MT Tanton ◽  
RB Cunningham
Keyword(s):  
Fungal Species ◽  
Forest Site ◽  
South Eastern ◽  
Percentage Occurrence ◽  
Eucalypt Forest ◽  
Faecal Analysis ◽  
Eastern Australia ◽  
Autumn And Winter ◽  
Potorous Tridactylus ◽  
South Eastern Australia

The diet of the long-nosed potoroo (Potorous tridactylus), a medium-sized ground-dwelling marsupial, was monitored (using faecal analysis) in a multiaged eucalypt forest site, and a regrowth eucalypt forest site in south-eastern Australia. In the multiaged forest P. tridactylus was primarily mycophagous, consuming the sporocarps (fruiting bodies) of at least 58 fungal species. Most of these taxa were hypogeal (underground fruiting) basidiomycetes thought to form mycorrhizae on the roots of a variety of plants. The percentage occurrence of fungus in faeces decreased in spring and summer and increased in autumn and winter. This pattern was opposite to the changing occurrence in faeces of other food types, and the percentage occurrence of spores of a major fungus species. At the regrowth forest site the quantity of fungus in faeces of P. tridactylus was lower but more constant over time. There were also differences in the percentage occurrence of spores of at least two fungal species. Additionally, the diversity of fungal taxa found as spores in faeces at the regrowth site was significantly lower (on average) than that recorded in faeces from the multiaged site. Differences in the fungal diets of the two P. tridactylus populations may be partially attributable to the disturbance (fire and logging) histories of each site.

Energy Invested in Reproduction by Thick-Billed Murres (Uria lomvia)

The Auk ◽  
1985 ◽  
Vol 102 (3) ◽  
pp. 447-458 ◽  
Author(s):  
A. J. Gaston
Keyword(s):  
Energy Expenditure ◽  
Total Energy ◽  
Reproductive Activity ◽  
Total Energy Expenditure ◽  
Energy Budgets ◽  
Uria Lomvia ◽  
Energy Investment ◽  
Cepphus Grylle ◽  
The Difference ◽  
Time And Energy

Abstract Pelagic seabirds that lay single-egg clutches have been thought to invest less energy in reproduction than inshore-feeding species that rear more than one young. To examine this idea I calculated time and energy budgets for Thick-billed Murres (Uria lomvia) breeding at two large arctic colonies and compared their energy expenditure with that of a hypothetical group (shirkers) that was capable of feeding at the same rate but did not attempt any reproductive activity. The difference in energy investment between breeders and shirkers was strongly dependent on the average foraging range. I also compared my results with similar estimates for inshore-feeding Black Guillemots (Cepphus grylle). For the two Thick-billed Murre colonies, energy allocated to reproduction represented 30% and 24% of total energy expenditure during the breeding season. These values exceed the estimates for Black Guillemots. The amount of energy invested by Thick-billed Murres at the colonies considered probably is similar to that invested by other seabirds laying larger clutches and rearing heavier young.

Seasonal Consumption by Dace (Phoxinus eos × P. neogaeus): A Comparison between Field and Bioenergetic Model Estimates

1994 ◽  
Vol 51 (11) ◽  
pp. 2558-2567 ◽  
Author(s):  
Marc Trudel ◽  
Daniel Boisclair
Keyword(s):  
Water Temperature ◽  
Feeding Rate ◽  
Fish Growth ◽  
Daily Ration ◽  
Bioenergetic Model ◽  
Direct Estimate ◽  
Energy Expenditures ◽  
Caloric Density ◽  
Independent Field ◽  
Consumption Rates

We compared the predictions of two bioenergetic models with independent field-derived estimates of consumption rates for dace (Phoxinus eos × P. neogaeus). These two models differ only in the energy that fish allocate to standard metabolism and activity. Daily ration and body mass of age 3+ dace from Lake Triton were estimated on 29 occasions during a 67-d period (June 22 – August 27, 1992). Water temperature and caloric density of fish and food were also monitored. Fish growth was on average 2.5 cal∙d−1 (1 cal = 4.19 J). Observed cumulative consumption for an average fish was 7.6 kcal. Seasonal consumption predicted by the first and second models was 33.5 and 6.5 kcal, respectively. The prediction of the second model was not significantly different from our direct estimate. The second bioenergetic model can be used to accurately predict the feeding rate of dace in the field by using models of maximum standard respiration (MSR) currently available in the literature (intercept = 0.015, slope = −0.2) with an activity multiplier of 1. Alternatively, because these models often include energy expenditures associated with digestion and/or activity, a MSR model having an intercept of 0.006 with an activity multiplier of 3 can also be used.

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