Seasonal feeding on Zostera capricorni seeds by Juvenile Penaeus esculentus (Crustacea: Decapoda) in Moreton Bay, Queensland

1990 ◽  
Vol 41 (2) ◽  
pp. 301 ◽  
Author(s):  
TJ Wassenberg
Keyword(s):  
Energy Content ◽  
Dry Weight ◽  
Seagrass Beds ◽  
Natural Diet ◽  
Food Items ◽  
Moreton Bay ◽  
Mean Size ◽  
Mature Seeds ◽  
Vegetable Material ◽  
Zostera Capricorni

The natural diet of juveniles of Penaeus esculentus Haswell (mean size 13.0 � 3.3 mm CL) collected from a seagrass (Zostera capricorni Aschers.) bed in Moreton Bay over 18 months was studied. There was a marked seasonal change in the occurrence of Z. capricorni seeds in their diet. These seeds made up to 1370 of the ash-free dry weight of the prawns' diet in November but disappeared completely from the diet between June and September. When seeds were not available, juvenile P. esculentus ate filamentous algae. Prawns less than 8 mm CL were not found with seeds in their foregut. There was no indication that prawns feed on seeds because of a shortage of other food items such as crustaceans or gastropods. Prawns studied in the laboratory removed seeds from the spathes and selected mature seeds. The seeds (each about 0.75 mg dry weight) had an energy content of 15.36 kJ g-1 dry weight. Seeds were found at densities of 456 m-2 in the seagrass beds. This study and other studies indicate that many species of juvenile penaeids incorporate vegetable material into their diet.

Natural diet of the tiger prawns Penaeus esculentus and P. semisulcatus

1987 ◽  
Vol 38 (1) ◽  
pp. 169 ◽  
Author(s):  
TJ Wassenberg ◽  
BJ Hill
Keyword(s):  
Regional Differences ◽  
Benthic Fauna ◽  
Gut Contents ◽  
Frequency Of Occurrence ◽  
Seagrass Beds ◽  
Natural Diet ◽  
Food Items ◽  
Moreton Bay ◽  
Harpacticoid Copepods ◽  
Common Items

Foregut contents of 702 P. esculentus and 426 P. semisulcatus collected from seagrass and offshore habitats in the Gulf of Carpentaria, Torres Strait and Moreton Bay between December 1983 and March 1984 were analysed, and the numerical composition and frequency of occurrence of food items in the diet were compared statistically. Periodicity in feeding was examined in adult prawns collected in hourly 20-min trawls overnight. Gut contents from these prawns were weighed and corrected for size by an empirically derived relationship V = 0.00931l2.818 between gut volume (V, �l) and carapace length (I, mm). The guts of both species were partially filled with food throughout the night. Bivalves, gastropods, ophiuroids, crustaceans and polychaetes were the most abundant food items of both species. Dietary composition overlapped for both species caught in the same trawl, but significant differences (P<0.05) were found in average numbers of pariicuiar items. No significani differences (P > 0.05) in numerical composition or frequency of occurrence of dietary items were found between the sexes of either species. Bivalves, gastropods and crustaceans were the most common items in juvenile and adult P. semisulcatus. Bivalves and gastropods were the most common food items in juvenile and adult P. esculentus. Bivalves were more common in adult than in juvenile P. esculentus. Ophiuroids were found more frequently with larger size of P. esculentus but were constant in all sizes of P. semisulcatus. The only meiofauna found in either species in significant numbers were harpacticoid copepods and these were found mainly in prawns from seagrass beds. P. esculentus and P. semisulcatus appear to eat similar taxa of benthic fauna. Quantitative differences between the diets of both species of prawns captured in the same trawl suggest that they are selective in their diet. Strong regional differences in diet were probably due to differences in the availability of prey.

Distribution of seagrasses, and their fish and penaeid prawn communities, in Cairns harbour, a tropical estuary, Northern Queensland, Australia

1993 ◽  
Vol 44 (1) ◽  
pp. 193 ◽  
Author(s):  
RG Coles ◽  
WJ Lee Long ◽  
RA Watson ◽  
KJ Derbyshire
Keyword(s):  
Fish Species ◽  
Juvenile Fish ◽  
Dry Weight ◽  
Common Species ◽  
Shoot Density ◽  
Seagrass Beds ◽  
Commercial Fish ◽  
North Eastern ◽  
Commercial Species ◽  
Zostera Capricorni

From aerial photography (July 1987) and diving surveys (February 1988), 876 ha of seagrasses (eight species) were mapped in Cairns Harbour, tropical north-eastern Queensland. Zostera capricorni was the most common seagrass species and had the greatest biomass at 79 g m-2 dry weight of stems and leaves and 180 g m-2 dry weight of roots and rhizomes. The maximum shoot density found was 4798 shoots m-2 of Halodule pinifolia, the second most common species. Seagrasses were found only between 0.5 and 5.0 m below mean sea level. Zostera capricorni was found at the shallowest depths, Halodule pinifolia at the deepest depths. Twenty species of penaeid prawns, nine of which are marketed commercially, were sampled from the seagrass beds. Abundances of prawns of commercial species were significantly greater on seagrass-covered substrata than on nonvegetated substrata. Overall, 5614 mostly small or juvenile fish, representing 134 taxa, were sampled from seagrasses in Cairns Harbour. The most numerous fish species were a goby, Yongeichthys criniger, and a pony fish, Leiognathus splendens. Only 15 species were highly valued as recreational fish, and only 11 species were highly valued as commercial fish. Of the fish species, five (4%) were highly valued species of both groups. The density of fish on the seagrass beds was estimated to be 8809 fish ha-1.

Trophic ecology and diet of Hydra vulgaris (Cnidaria; Hydrozoa)

2017 ◽  
Vol 67 (3-4) ◽  
pp. 287-300 ◽  
Author(s):  
María I. Deserti ◽  
Karina S. Esquius ◽  
Alicia H. Escalante ◽  
Fabián H. Acuña
Keyword(s):  
Nutritional Value ◽  
Trophic Ecology ◽  
Buenos Aires ◽  
Feeding Habits ◽  
Natural Habitat ◽  
Buenos Aires Province ◽  
Hydra Vulgaris ◽  
Natural Diet ◽  
Food Items ◽  
Invertebrate Prey

Hydra is a genus of common, sessile, solitary freshwater cnidarians, which are defined as carnivorous and efficient predators. The purpose of this study was to obtain information on the feeding habits and diet of Hydra vulgaris collected from its natural habitat in Nahuel Rucá Lake (Buenos Aires Province, Argentina). We found three categories of food items in the coelenteron: algae, fungi, and small invertebrates. Algae dominated the diet in terms of abundance and frequency of occurrence, but their volumetric contribution was almost negligible, as was their possible nutritional value. Invertebrate prey captured, using active predation, represented the major volumetric contribution, with four different taxa found. The detection of phytoplankton in the gastral cavities reveals the input of some organisms present in the surrounding waters in addition to the invertebrates. This information is novel, since studies on the natural diet of Hydra are very scarce.

Effects of Lyngbya majuscula (Cyanophycea) blooms on sediment nutrients and meiofaunal assemblages in seagrass beds in Moreton Bay, Australia

2006 ◽  
Vol 57 (2) ◽  
pp. 155 ◽  
Author(s):  
Rosa García ◽  
Ron W. Johnstone
Keyword(s):  
Depth Distribution ◽  
East Coast ◽  
Oxygen Depletion ◽  
Seagrass Beds ◽  
Biogeochemical Processes ◽  
Sediment Depth ◽  
Lyngbya Majuscula ◽  
Moreton Bay ◽  
Bloom Period ◽  
Abundance And Distribution

Blooms of Lyngbya majuscula have been increasingly recorded in the waters of Moreton Bay, on the south-east coast of Queensland, Australia. The influences of these blooms on sediment infauna and the implications for sediment biogeochemical processes was studied. Sediment samples were taken from Moreton Bay banks during and after the bloom season. The deposition of L. majuscula seems to be responsible for the higher total Kjedahl nitrogen (TKN) concentrations measured during the bloom period. Total organic carbon (TOC) concentrations did not change. Lyngbya majuscula blooms had a marked influence on the meiobenthos. Nematodes, copepods and polychaetes were the most abundant groups of meiofauna, and the bloom produced a decrease in the abundance and a change in the sediment depth distribution of these organisms. The distribution of nematodes, copepods and polychaetes in sediment became shallower. Further, the bloom did not affect the abundance and distribution of polychaetes as strongly as it did copepods and nematodes. The changes observed in the distribution of meiofauna in the sediment during the bloom period indicate that L. majuscula produces oxygen depletion in sediments, and that different fauna seem to be affected to different degrees.

scholarly journals Seed Harvesting Time Affects Seedling Emergence, Vigour and Growth: Case Study of Rumex turcomanicus Czerep. (Polygonaceae)

2013 ◽  
Vol 5 (2) ◽  
pp. 244-248
Author(s):  
Morteza ALIREZAIE NOGHONDAR ◽  
Majid AZIZI
Keyword(s):  
Growth Traits ◽  
Seedling Emergence ◽  
Seed Storage ◽  
Dry Weight ◽  
Seedling Vigour ◽  
Root And Shoot Length ◽  
Seed Harvesting ◽  
Vigour Index ◽  
Emergence Percentage ◽  
Mature Seeds

Rumex turcomanicus Czerep., belonging to family Polygonaceae, is one of native green vegetable in Northeast Iran. Despite the high consumption, its seed germination and dormancy aspects is inconsiderable. In order to investigate the effects of seed harvesting date on seedling emergence, vigour and growth traits of R. turcomanicus Czerep., the seeds were harvested at five different times, i.e., two weeks after fruiting (WAF), 6WAF, 8WAF (mature seeds), 2 month after seed ripening (MASR) and 4MASR, and were sowed immediately, at agricultural college of Ferdowsi university of Mashhad, Iran in 2012-2013. The results was showed that the highest and lowest of seedling emergence percentage, seedling emergence rate, seedling vigour index, seedling fresh and dry weight, seedling root and shoot length, total seedling length and %final normal seedling (%FNS) was obtained in the seeds which were sowed 4MASR and 2WAF, respectively. Maximum and minimum of mean emergence time (MET) was observed in the seeds which were sowed 2WAF and 4MASR, respectively. Relationship between %FNS and MET and between %FNS and emergence percentage was highly significantly negative (-0.961) and positive (+0.962), respectively. Based on the results of this experiment, it seems that the problem of germination in most of the Rumex turcomanicus Czerep. seeds, is probably due to a kind of morphological dormancy, which is remained in most of the fresh seeds (collected 2WAF), and eliminated in the mature seeds (collected 2MASR). Also dry seed storage of the mature seeds for two months was improved seedling emergence and vigour, significantly.

The life history of Branchinecta mackini Dexter (Crustacea: Anostraca) in an argillotrophic lake of Alberta

1977 ◽  
Vol 55 (1) ◽  
pp. 161-168 ◽  
Author(s):  
Graham R. Daborn
Keyword(s):  
Organic Matter ◽  
Life History ◽  
Life Cycle ◽  
Growth Rates ◽  
Dry Weight ◽  
Fairy Shrimp ◽  
Maximum Biomass ◽  
History Of ◽  
Mean Size

The life history of B. mackini was studied in a large argillotrophic lake during 1970–1972. Hatching began immediately after spring thaw and was terminated by rising salinity 10 days to 2 weeks later. Growth rates reached maxima of 1 mm/day at 4 weeks of age and then declined as mean size approached 22–23 mm at 7–8 weeks. Clutch sizes varied as a function of female length. Maximum biomass of 580 mg dry weight/m2 (2700 cal/m2) was reached in late May, of which 3.9% per day was consumed by B. gigas. Source of the energy is presumed to be a bacteria – organic matter complex associated with suspended particles. Life cycle details are compared with other fairy shrimp species and the role of B. mackini in the community is discussed.

Trophic ecology of a benthic intertidal hydroid, Tubularia crocea, at Mar del Plata, Argentina

2005 ◽  
Vol 85 (2) ◽  
pp. 307-312 ◽  
Author(s):  
Gabriel N. Genzano
Keyword(s):  
Trophic Ecology ◽  
Feeding Rate ◽  
Prey Availability ◽  
Stomach Contents ◽  
Dry Weight ◽  
Benthic Organisms ◽  
Food Items ◽  
The Mean ◽  
The Relationship ◽  
Prey Items

The trophic ecology and seasonal changes in the diet of the intertidal hydrozoan Tubularia crocea were studied analysing the enteron contents of hydranths collected each season of the year. The relationship between feeding rate, prey availability, and re-suspension processes caused by tidal currents was also assessed. The most prevalent food items were diatoms and crustaceans. The most remarkable differences occurred during summer, when crustaceans were more abundant than diatoms. Conversely, diatoms were the most abundant prey during other seasons, and they were almost the only prey found during winter. There was no relationship between abundances of primary prey items in the water column and their occurrences in stomach contents. Instead, most prey items consisted of benthic organisms, primarily two species of diatoms (Grammatophora marina and Licmophora abreviatta) and fragments (usually appendages) of the amphipods Caprella sp. and Jassa falcata. Most food items were digested within 4–4·5 hours. The mean number of items captured per polyp per day was determined to be 115·2±19·2 in summer, 93·6±14·4 in autumn, 76·8±21·6 in winter and 199·2±31·2 in spring. Prey biomass (dry weight) polyp−1 d−1 was 5·1 μg in summer, 2·3 μg in autumn, 1·8 μg in winter, and 6·3 μg in spring. These values, in relation to hydranth biomass (55·3 μg; dry weight), were equivalent to a food intake polyp−1 d−1 of 9·3%, 4·2%, 3·2% and 11·5% of its own weight, respectively.

scholarly journals IN VITRO CULTURE OF IMMATURE TAXUS EMBRYOS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 698d-698 ◽  
Author(s):  
Ching-yeh Hu ◽  
Lee Wang ◽  
Bernard Wu
Keyword(s):  
Embryo Culture ◽  
Large Population ◽  
Dry Weight ◽  
Ms Medium ◽  
Embryonic Growth ◽  
Embryo Dormancy ◽  
Taxol Production ◽  
Initial Medium ◽  
Mature Seeds

Embryo culture can by-pass yew (Taxus) seed dormancy and produce large population of seedlings to be screened for the anticancer drug, taxol, production. Immature linear embryos from seeds of T. baccata, T. brevifolia. T. cuspidata, and T. media were dissected and cultured. B5 medium supported the best embryonic growth during the initial two week's culture for T. cuspidata and T. baccata. T. brevifolia grew faster on MS medium. Weak embryo dormancy was encountered in T. brevifolia and T. cuspidata from the mature seeds but not from the immature ones. No embryonic growth had been observed in T. media dissected from mature seeds due to strong dormancy. Developing embryos were subsequently transferred to 1/2X B5 medium for germination. Rooting percentage in the mature seed derived T. brevifolia embryos increased from 12.5 to 63.6 when 30 μM GA3 was added to the initial medium. Several hundreds of seedlings of T. baccata. T. brevifolia and T. cuspidata had been acclimatized to the greenhouse conditions. The taxol content of resultant T. cuspidata seedlings was 0.027% (dry weight), while that of T. brevifolia obtained from the wild twig was 0.030%.

scholarly journals Yield of green fodder of annual mixtures with participation of sudanese grass in conditions of Polisya

1970 ◽  
pp. 161-171
Author(s):  
O.V. Vishnevska ◽  
O.V. Markina
Keyword(s):  
Energy Content ◽  
Growth Yield ◽  
Dry Weight ◽  
Component Composition ◽  
Metabolic Energy ◽  
Dominant Component ◽  
Green Fodder ◽  
Digestible Protein ◽  
Fertilization System ◽  
Feed Unit

Purpose. To study the features of the formation, growth, yield and nutritional value of mixtures involving Sudanese grass in the production of green fodder with different component composition and fertilization system. Methods. Field, laboratory, mathematical. Results. According to the results of the studies, it was found that the dominant component of cenoses, the Sudanese grass, forms the height of plants at the level of 87-151 cm, the components of the mixtures – 48,4-95,9 cm. The fertilization system contributed to the linear development of cenosis plants by 9-39% in Sudanese grass and 6-62% in the components of mixtures, compared with the control options. The results of the studies of the cenosis productivity with participation of Sudanese grass, which on the sod-podzolic soils of Polisya amounted to 16,2-44,8 t/ha of greenery, or 3,3-9,1 t/ha of dry weight, the efficiency of the fertilization system was up to 38%. The yield of nutrients was 2.54-7.64 t/ha of feed units and 0.47-1.41 t/ha of digestible protein, the fertilizer system increased the yield of nutrients by 6-72%. The feed unit is provided with digestible protein at the level of 168.7-200.6 g. It was found that the content of exchangeable energy in 1 kg of feed obtained from mixtures is 9.6-10.4 mJ. According to the competitiveness coefficient (K = 1.47-2.74), the optimal fertilization system for these cenoses was selected – N16Р16К16. Conclusions. In terms of productivity (16.2-44.8 t/ha of green, or 3.3-9.1 t/ha of dry, weight) and nutrition (168.7-200.6 g feed unit digestible protein availability, metabolic energy content – 9,6-10,4 mJ per 1 kg of feed), multicomponent cenoses with the participation of Sudanese grass for the production of green feed in the Polisya zone have been developed.

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