Peter R. B. Ward

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Diatoms dominate spring bloom phytoplankton assemblages in temperate waters and coastal upwelling regions of the global ocean. Copepods usually dominate the zooplankton in these regions and are the prey of many larval fish species. Recent laboratory studies suggest that diatoms may have a deleterious effect on the success of copepod egg hatching. These(More)
A rapid automated method for urinary creatinine with the Jaffé reaction is described. Interferences by protein, glucose and ketones are circumvented by the reaction rate kinetics. The precision and accuracy of this centrifugal method on the ENI-Gemsaec analyzer are comparable to the manual end-point Jaffé reaction with deproteinization and to the common(More)
We identify changes in pelagic longline fishing gear and practices that need to be accounted for in stock assessments. Pelagic longline fishers have continuously modified their fishing gear and practices to improve fishing power and catchability, which has altered the relationship between catch rates and abundance. Advances in technology resulted in the(More)
Zooplankton abundance and biomass were determined during January 1990 at two stations to the north-west of South Georgia using a Longhurst Hardy Plankton Recorder (LHPR). At both shelf and oceanic station sites, zooplankton biomass, (excluding Euphausia superba), was found to be ca. 13 g dry mass m−2. Copepods and small euphausiids dominated the catches.(More)
The Commonwealth of Australia acting through the Bureau of Rural Sciences has exercised due care and skill in the preparation and compilation of the information and data set out in this publication. Notwithstanding, the Bureau of Rural Sciences, its employees and advisers disclaim all liability, including liability for negligence, for any loss, damage,(More)
The interaction between feeding activity, swarming behaviour and vertical migration in Antarctic krill, Euphausia superba Dana, was examined by a combination of laboratory physiology studies and intensive field sampling of a patch of krill located NE of South Georgia, in April 1980. The combined use of echolocation and a series of timed net hauls from(More)
Measurements of the vertical temperature in tropical Lake McIlwaine were used to calculate the time-averaged (≃ 6 months) vertical diffusivity coefficient (Kz) in the metalimnion and hypolimnion. The mean value of Kz (0.21 cm2 s−1) was correlated with the lake surface area. The mass transport rates of PO4-P and NH4-N, upward from the hypolimnion to the(More)
Egg hatching times were determined at a range of temperatures for four species of commonly occurring Antarctic copepods. At a given temperature the eggs of Rhincalanus gigas took longest to hatch, up to 9 days at 0°C, followed by those of Calanoides acutus, Calanus propinquus and Calanus simillimus. A Bělehrádeks temperature function with the parameter b(More)
Gymnoscopelus braueri, Gymnoscopelus fraseri and Gymnoscopelus nicholsi are common in the Southern Ocean mesopelagic fish community. However, their ecology is poorly understood in the region. This study investigated spatial and temporal patterns in their abundance, population structure and diets at different times of year within the Scotia Sea to ascertain(More)
  • Peter Ward
  • Reviews in Fish Biology and Fisheries
  • 2007
I quantify the effects of 11 variables on the catchability and fishing power of pelagic longlines, which are used to catch tunas and billfishes in the open ocean. Extension of the depth range and the duration of longline operations have reduced the catchability of several epipelagic species, such as mako sharks (Isurus spp.), since industrial longlining(More)