Hydrodynamic and water column properties at six stations associated with mussel farming in Pelorus sound, 1984–85

Abstract

Mussel farming places a benthic organism in a pelagic environment; it is therefore important to understand the driving force that transports the food to the mussels. The hydrodynamic regimes in the sidearms and embayments in Pelorus Sound are dominated by the lunar tide, and a net estuarine circulation in the main channel flowing inwards along the bottom and outwards along the top. Salinity gradients extend throughout the sound from the river inflows, with strongest density stratification in the sidearms and embayments: nearest the head of the sound. There, the water column is separated at the pycnocline into upper and lower layers which tend to M91014

Nutrient cycling and fluxes in Beatrix Bay, Pelorus Sound, New Zealand

“…The recent construction of a mussel carrying capacity model (James & Ross 1996) requires a more detailed parameterisation of the fluxes and processes associated with the N sources and sinks for Beatrix Bay. Because of the complex hydrodynamics of Pelorus Sound (Heath 1976;Gibbs et al 1991;Hadfield & Sutton 1996;Sutton & Hadfield 1997;Proctor & Hadfield 1998), quantitative linkages between the components of the N cycle are not obvious. Observations on phytoplankton uptake, grazing by mussels and zooplankton, sedimentation of particulate N, excretion, and sediment nutrient regeneration may be confounded by transport in and out of the bay.…”

“…In Pelorus Sound, major sources of N have been attributed to riverine inflows, sediment nutrient release, and oceanic exchange via estuarine circulation (Bradford et al 1986(Bradford et al ,1987MacKenzie et al 1986;Gibbs et al 1991Gibbs et al , 1992Gibbs 1993;Proctor & Hadfield 1996;Ross et al 1998). The recent construction of a mussel carrying capacity model (James & Ross 1996) requires a more detailed parameterisation of the fluxes and processes associated with the N sources and sinks for Beatrix Bay.…”

Characterising biofouling communities on mussel farms along an environmental gradient: a step towards improved risk management

“…1). The 3 area boundaries were set in accordance with previously conducted dispersal studies (Knight et al 2010), as well as the known environmental gradients and hydrodynamic characteristics in Pelorus Sound (Heath 1974, Gibbs et al 1991, Broekhuizen et al 2015. Each mussel farm was considered to be a single replicate within the larger area of interest (inner, middle, outer).…”

“…In contrast, mussel farms near the head of Pelorus Sound are in shallower, sheltered areas, experiencing low wave action and periods of reduced or stagnant water flow, which may induce warmer summer temperatures (Gibbs et al 1991). Furthermore, episodic storm events can generate high freshwater inputs from the Pelorus and Kaituna rivers into areas near the head of Pelorus Sound (Gibbs et al 1991, Broekhuizen et al 2015. Differential cover of certain biofouling taxa and associated differences in community structure found in this study could therefore be a reflection of tolerance to local environmental conditions.…”

“…Reduced flushing rates and strong stratification have been recorded within the side arms and embayments near the head of Pelorus Sound. Stratification is generally driven by salinity (Heath 1974, Gibbs et al 1991, with a gradual decrease in mean salinity towards the confluence with Kenepuru Sound (Heath 1982, Broekhuizen et al 2015 (Fig. 2a,b).…”