Pomadasys

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform

N Deacon - One of the best experts on this subject based on the ideXlab platform.

T Hecht - One of the best experts on this subject based on the ideXlab platform.

  • effect of protein level and varying protein lipid concentrations on growth characteristics of juvenile spotted grunter Pomadasys commersonnii haemulidae
    African Journal of Marine Science, 2003
    Co-Authors: T Hecht, A Irish, J Sales
    Abstract:

    A 60-day feeding trial was conducted to evaluate the effects of dietary crude protein level on growth, feed conversion and protein efficiency ratio of juvenile (3–6 g) spotted grunter Pomadasys commersonnii. In the experiment, six semi-purified diets containing casein and fishmeal as protein sources, and with crude protein levels ranging from 35 to 60%, were fed to three replicate groups of fish per treatment in a recirculating system at the optimum temperature for growth. The relationships between dietary crude protein level and growth parameters were analysed by broken-line regression models. Results suggest that 48 – 50% dietary protein is needed for optimum growth and feed conversion for P. commersonnii. In a second experiment, three protein levels (35, 45 and 55%) at three different lipid concentrations (6, 8 and 12%) were used to formulate nine semi-purified diets that were fed for 60 days to triplicate groups of fish per treatment. Results suggest that a diet of at least 45% protein with a 12% lipi...

  • Effect of Protein Level and Varying Protein – Lipid Concentrations on Growth Characteristics of Juvenile Spotted Grunter Pomadasys Commersonnii (Haemulidae)
    African Journal of Marine Science, 2003
    Co-Authors: T Hecht, A Irish, J Sales
    Abstract:

    A 60-day feeding trial was conducted to evaluate the effects of dietary crude protein level on growth, feed conversion and protein efficiency ratio of juvenile (3–6 g) spotted grunter Pomadasys commersonnii. In the experiment, six semi-purified diets containing casein and fishmeal as protein sources, and with crude protein levels ranging from 35 to 60%, were fed to three replicate groups of fish per treatment in a recirculating system at the optimum temperature for growth. The relationships between dietary crude protein level and growth parameters were analysed by broken-line regression models. Results suggest that 48 – 50% dietary protein is needed for optimum growth and feed conversion for P. commersonnii. In a second experiment, three protein levels (35, 45 and 55%) at three different lipid concentrations (6, 8 and 12%) were used to formulate nine semi-purified diets that were fed for 60 days to triplicate groups of fish per treatment. Results suggest that a diet of at least 45% protein with a 12% lipi...

  • the effect of reduced salinity on growth food conversion and protein efficiency ratio in juvenile spotted grunter Pomadasys commersonnii lacepede teleostei haemulidae
    Aquaculture Research, 1999
    Co-Authors: N Deacon, T Hecht
    Abstract:

    Salinity has been proven to have a significant effect on the growth and survival of anadromous fish species; however, there is a paucity of information regarding its effect on euryhaline marine species. Experiments were conducted to examine the effect of hyposalinity on the osmoregulation and growth of juvenile spotted grunter, Pomadasys commersonnii (Lacepede). Although the spotted grunter is considered to be a strong osmoregulator, growth performance and survival was compromised below isosmotic concentrations. The growth rate, condition and food conversion of fish in low salinity (5‰) were lower than in either isosmotic (12‰) or hyperosmotic (25‰ and 35‰) conditions. Mortality was also significantly higher at 5‰. From these results, it is concluded that P. commersonnii can be successfully cultured in salinities ranging from 12‰ to full-strength sea water (35‰).

  • the effect of temperature and photoperiod on the growth of juvenile spotted grunter Pomadasys commersonnii pisces haemulidae
    African Journal of Marine Science, 1996
    Co-Authors: N Deacon, T Hecht
    Abstract:

    All measured growth parameters of juvenile spotted grunter Pomadasys commersonnii were significantly related to temperatures in the range 20,5 to 28,5°C. Optimum growth, condition and food conversion of juvenile grunter occurred at 24,5°C. Photoperiod had a more subtle influence on growth. Condition factor of fish held under a 12L:12D photoperiod was significantly better than at protracted (l6L:8D) or shortened (8L:16D) light regimes. Growth and food conversion were not significantly influenced by photoperiod.

  • observations on the thermoregulatory behaviour of juvenile spotted grunter Pomadasys commersonnii haemulidae pisces
    Journal of Applied Ichthyology, 1995
    Co-Authors: N Deacon, T Hecht
    Abstract:

    The thermal preference of juvenile spotted grunter, Pomadasys commersonnii (Haemulidae), was determined in a horizontal thermal gradient. Temperature preference was tested over a range of 17–31°C at three salinities. The modal temperature preferenda at 5, 12 and 35 ppt were 25°C, 24.5°C and 25°C, respectively. They were not significantly different. The thermal preferendum of this species was found to be between 24°C and 25°C. Supplementary experiments were conducted to test the stability of the final thermal preferendum. Initial observation of the behaviour of juvenile spotted grunter indicated the presence of a strong circadian rhythm. However, diel variation in activity did not influence temperature preference. These data are important for the development of a culture protocol for this euryhaline species.

Thomas Hecht - One of the best experts on this subject based on the ideXlab platform.

J Dashti - One of the best experts on this subject based on the ideXlab platform.

  • age validation of nagroor Pomadasys kaakan cuvier 1830 family haemulidae in kuwaiti waters
    Fisheries Research, 2001
    Co-Authors: M Alhusaini, S Alayoub, J Dashti
    Abstract:

    Abstract Daily increments in the sagittal otoliths of young nagroor, Pomadasys kaakan (Family: Haemulidae) were investigated using alizarin complexone (ALZ). Counts between annual marks and marginal increment analysis of adult wild fish were used to validate the annuli and time of their formation. Young nagroor deposited daily otolith increments under laboratory conditions at 17–20°C. Compared to cultured fish, the daily increments of wild fish were relatively easy to discern and count. The annulus was composed of striated aggregations all round the otolith’s thin transverse sections. The average daily increment counts between the annuli were 266, 326 and 276 for the first 3 years, respectively; however, this method is unsuitable for validation of the second and later annuli due to a lower increment number than expected of 365 increments. The recent annuli formed on the otolith edge were observed in most of the March–May otolith samples. All data of marginal increment of otoliths were pooled for the years 1992–1995, which indicated that the peak formation of annuli was during March–June. The data also indicate that juvenile and immature fish (14–22 cm total length) form the first annulus before the onset of ovarian maturation.

A-r Childs - One of the best experts on this subject based on the ideXlab platform.

  • estuarine and coastal connectivity of an estuarine dependent fishery species Pomadasys commersonnii haemulidae
    African Journal of Marine Science, 2017
    Co-Authors: Mh Dames, A-r Childs, Eva B. Thorstad, Rhett H. Bennett, P D Cowley, T. F. Næsje
    Abstract:

    Understanding the level of connectivity between estuarine and coastal waters is essential for appropriate management of estuarine-associated taxa. Most studies have focused on the role of a single estuary, while limited research exists on the importance of multiple estuaries to individuals of estuarine-associated species. This study used acoustic telemetry to assess the usage of multiple estuaries and coastal waters by the estuarine-dependent spotted grunter Pomadasys commersonnii. Twenty-six adult fish were tagged with acoustic transmitters in the Kariega and Bushmans estuaries, South Africa, and their movements along a 300-km stretch of Indian Ocean coastline were monitored for up to 17 months. Tagged individuals spent most of their time in the estuary where they were tagged (55% and 85% for fish tagged in the two estuaries, respectively), followed by time in the sea (30% and 15%) and in other estuaries (15% and <1%). The mean durations of sea trips for fish tagged in the Kariega Estuary or Bushmans Est...

  • Estuarine and coastal connectivity of an estuarine-dependent fishery species, Pomadasys commersonnii (Haemulidae)
    African Journal of Marine Science, 2017
    Co-Authors: Mh Dames, A-r Childs, Paul D. Cowley, Eva B. Thorstad, Rhett H. Bennett, T. F. Næsje
    Abstract:

    Understanding the level of connectivity between estuarine and coastal waters is essential for appropriate management of estuarine-associated taxa. Most studies have focused on the role of a single estuary, while limited research exists on the importance of multiple estuaries to individuals of estuarine-associated species. This study used acoustic telemetry to assess the usage of multiple estuaries and coastal waters by the estuarine-dependent spotted grunter Pomadasys commersonnii. Twenty-six adult fish were tagged with acoustic transmitters in the Kariega and Bushmans estuaries, South Africa, and their movements along a 300-km stretch of Indian Ocean coastline were monitored for up to 17 months. Tagged individuals spent most of their time in the estuary where they were tagged (55% and 85% for fish tagged in the two estuaries, respectively), followed by time in the sea (30% and 15%) and in other estuaries (15% and

  • influence of prey abundance and abiotic factors on the long term home range and movement dynamics of spotted grunter Pomadasys commersonnii in an intermittently open estuary
    African Journal of Marine Science, 2016
    Co-Authors: B A Maree, A-r Childs, Tor F. Næsje, P D Cowley, A I Terorde, Eva B. Thorstad
    Abstract:

    Long-term home-range and movement dynamics of spotted grunter Pomadasys commersonnii and the distribution of their dominant prey, the sandprawn Callichirus kraussi, were investigated in the intermittently open East Kleinemonde Estuary, South Africa. In addition, the effects of fish length, diel cycle, season and other abiotic factors on home range and area use were examined. Nine adult spotted grunter (326–489 mm total length) were tagged with acoustic transmitters, and their movements were studied by manual tracking on six consecutive days and nights during each of five tracking sessions from March to November 2004. In addition, movement patterns were recorded by stationary data-logging receivers. Kernel home ranges (95% utilised distribution) varied in size (mean: 76 797 m2 , range: 26 296–165 321 m2), but were all located in the lower one-third of the 3.6 km-long estuary. There was no effect of season, the diel cycle or fish length on the home-range estimates. However, the distribution of prey correspo...

  • home range of an estuarine dependent fish species Pomadasys commersonnii in a south african estuary
    Fisheries Management and Ecology, 2008
    Co-Authors: A-r Childs, Paul D. Cowley, Tor F. Næsje, Anthony J. Booth, Warren M. Potts, Eva B. Thorstad, Finn Økland
    Abstract:

    Abstract  The home range and area use of spotted grunter, Pomadasys commersonnii (Haemulidae) (Lacepede), were investigated in the Great Fish estuary, South Africa. Forty individuals (263–698 mm TL) were surgically implanted with acoustic-coded transmitters and manually tracked during two periods in 2003. Tagged fish spent on average 68 and 77% of the time in the estuary and the remaining time at sea during the two periods, respectively. While in the estuary, there was large variation in home range size, home range length and the number of home range areas amongst individuals. Larger fish had larger home ranges and more core areas than smaller fish. The home ranges of 29 individuals (74%) occurred in the lower reaches of the estuary, suggesting that the proclamation of a no-take zone in this high use area could benefit this over-exploited estuarine fishery species.

  • Estuarine use by spotted grunter Pomadasys commersonnii in a South African estuary, as determined by acoustic telemetry
    African Journal of Marine Science, 2008
    Co-Authors: A-r Childs, Paul D. Cowley, Tor F. Næsje, Anthony J. Booth, Warren M. Potts, Eva B. Thorstad, Finn Økland
    Abstract:

    Factors influencing estuarine use and marine excursions by spotted grunter Pomadasys commersonnii in the Great Fish Estuary, South Africa, were studied using manual and automated telemetry methods. In all, 20 individuals, ranging from 362 mm to 698 mm total length (TL), were caught and tagged with acoustic-coded transmitters in the estuary. Tagged individuals spent most time in the estuary (67%), interspersed with a number of marine excursions — 15 in all. The number (6–53) and mean duration (0.8–9.5 days) of sea excursions varied among individuals, and were correlated significantly with tide, time of day, fish size and various environmental conditions. On average, fish departed the estuary on the outgoing tide at night and returned to the estuary on the incoming tide during the day. Spotted grunter

Related terms

Pomadasys - 15 days free trial to Access Experts & Abstracts