Zooplankton Distribution in Relation to the Hydrology of the Derwent River Estuary

1978 ◽  
Vol 29 (6) ◽  
pp. 763 ◽  
Author(s):  
N Taw ◽  
DA Ritz
Keyword(s):  
Indicator Species ◽  
Coastal Waters ◽  
River Estuary ◽  
Marine Species ◽  
Copepod Species ◽  
Estuarine System ◽  
Freshwater Flow ◽  
Tidal Zone ◽  
Zooplankton Distribution ◽  
Plankton Distribution

The zooplankton of the Derwent River estuary was sampled during periods of high freshwater flow (October) and low freshwater flow (April). Zooplankton distribution was found to be similar at both times with only minor shifts in location. Observed plankton distribution is shown to correlate well with a hydrologically established zonation scheme. Despite continual exchange between oceanic, coastal and inshore coastal waters, there is only occasional estuarine penetration into the inshore region and little penetration of inshore plankton into the estuary. The tidal zone is shown to be stable, well defined and characterized by estuarine and marine species. It is suggested that in a similar estuarine system, where the zooplankton distribution is well known, the hydrological zones can be inferred. The estuary of the Werribee River, Victoria, contains most of the same copepod species and is similar in other ways to the Derwent River estuary. But the occurrence of indicator species in the marine region of the Derwent estuary suggests that it is subject to a stronger influence of open coastal and oceanic waters.

Influence of Subantartic and Subtropical Oceanic Water on the Zooplankton and Hydrology of Waters Adjacent to the Derwent River Estuary, South-eastern Tasmania

1979 ◽  
Vol 30 (2) ◽  
pp. 179 ◽  
Author(s):  
N Taw ◽  
DA Ritz
Keyword(s):  
Indicator Species ◽  
Strong Evidence ◽  
Coastal Waters ◽  
River Estuary ◽  
Water Masses ◽  
Seasonal Abundance ◽  
Oceanic Water ◽  
Subtropical Water ◽  
South Eastern ◽  
Subantarctic Water

The oceanic influence on coastal waters adjacent to the mouth of the Derwent River estuary was examined over a season using zooplankton samples. There is strong evidence to indicate the influence of oceanic water in Storm Bay and the mouth of the Derwent River estuary. The occurrence of indicator species suggests that the area is invaded by subantarctic water from August to January and by subtropical water most strongly in February and March. The seasonal abundance and distribu- tion of the major copepods (12 species), chaetognaths (three species), one euphausiid and one tunicate species are described in detail and the importance of these species as indicators of intrusion and mixing of water masses in this region is evaluated.

scholarly journals Spatiotemporal variation in size-structured populations using fishery data: an application to shortfin mako (Isurus oxyrinchus) in the Pacific Ocean

2017 ◽  
Vol 74 (11) ◽  
pp. 1765-1780 ◽  
Author(s):  
Mikihiko Kai ◽  
James T. Thorson ◽  
Kevin R. Piner ◽  
Mark N. Maunder
Keyword(s):  
Coastal Waters ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Marine Species ◽  
Structured Populations ◽  
Spatiotemporal Model ◽  
The North ◽  
Isurus Oxyrinchus ◽  
Shortfin Mako ◽  
Catch Rates

We develop a length-disaggregated, spatiotemporal, delta-generalized linear mixed model (GLMM) and apply the method to fishery-dependent catch rates of shortfin mako sharks (Isurus oxyrinchus) in the North Pacific. The spatiotemporal model may provide an improvement over conventional time-series and spatially stratified models by yielding more precise and biologically interpretable estimates of abundance. Including length data may provide additional information to better understand life history and habitat partitioning for marine species. Nominal catch rates were standardized using a GLMM framework with spatiotemporal and length composition data. The best-fitting model showed that most hotspots for “immature” shortfin mako occurred in the coastal waters of Japan, while hotspots for “subadult and adult” occurred in the offshore or coastal waters of Japan. We also found that size-specific catch rates provide an indication that there has been a recent increasing trend in stock abundance since 2008.

Hudson River Fishes and their Environment

2006 ◽  
Keyword(s):  
Striped Bass ◽  
River Estuary ◽  
Circulation Model ◽  
Hudson River ◽  
Hudson River Estuary ◽  
Freshwater Flow ◽  
East River ◽  
Particle Tracking Model ◽  
Tracking Model ◽  
Neutrally Buoyant

<em>Abstract.</em>—Our objectives were to determine if striped bass <em>Morone saxatilis </em>larvae were present in the East River and if so, could they have come from the Hudson River. To meet the first objective, we examined entrainment data collected at the Charles Poletti Power Plant (Poletti) during the years 1999 through 2002. To meet the second objective, we examined the simulated release of 168,000 neutrally buoyant, passive particles in the lower Hudson River Estuary, using a particle-tracking model that was linked to an estuarine circulation model. We also compared the abundance of striped bass post-yolk-sac larvae (PYSL) collected in the East River at Poletti with the abundance of striped bass PYSL collected in the Battery region of the lower Hudson River Estuary and the abundance of striped bass PYSL in the Battery region with freshwater flow in the estuary. Striped bass PYSL were collected by entrainment sampling in the East River at Poletti every year from 1999 through 2002. The striped bass PYSL in the East River probably came from the Hudson River Estuary because the median probability that neutrally buoyant, passive particles would be transported from the lower Hudson River Estuary to the upper East River and western Long Island Sound was 0.12, with a median transport time of 2 d, and because the mean density of striped bass PYSL was highest at Poletti and in the Battery region during the same year. The abundance of striped bass PYSL in the Battery region was higher when freshwater flow during May and early June was higher.

scholarly journals Tidal Mixing Signatures in the Hong Kong Coastal Waters from Satellite-Derived Sea Surface Temperature

2018 ◽  
Vol 11 (1) ◽  
pp. 5 ◽  
Author(s):  
R. Susanto ◽  
Jiayi Pan ◽  
Adam Devlin
Keyword(s):  
Hong Kong ◽  
High Resolution ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Coastal Waters ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Sea Surface ◽  
Tidal Mixing ◽  
Diurnal Tides

Tidal mixing in the coastal waters of Hong Kong was investigated using a combination of in situ observations and high-resolution satellite-derived sea surface temperature (SST) data. An indicator of tide-induced mixing is a fortnightly (spring-neap cycle) signature in SST due to nonlinear interactions between the two principal diurnal and the two principal semi-diurnal tides. Both semi-diurnal and diurnal tides have strong tidal amplitudes and currents near Hong Kong. As a result, both the near-fortnightly (Mf) and fortnightly (MSf) tides are enhanced due to nonlinear tidal signal interactions. In addition, these fortnightly tidal signals are modulated by seasonal variability, with the maximum seasonal modulation of fortnightly tides occurring during the monsoon transition periods in May and October. The largest fortnightly signals are found in the southwestern part of the Pearl River estuary. Tidal constituent properties vary by space and depth, and high-resolution SST plays a pivotal role in resolving the spatial characteristics of tidal mixing.

scholarly journals Remote Sensing Estimation of Sea Surface Salinity from GOCI Measurements in the Southern Yellow Sea

2019 ◽  
Vol 11 (7) ◽  
pp. 775 ◽  
Author(s):  
Deyong Sun ◽  
Xiaoping Su ◽  
Zhongfeng Qiu ◽  
Shengqiang Wang ◽  
Zhihua Mao ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Coastal Waters ◽  
Yangtze River ◽  
River Estuary ◽  
Sea Surface Salinity ◽  
Yangtze River Estuary ◽  
The Yangtze River ◽  
Surface Salinity ◽  
The Southern Yellow Sea ◽  
The Yangtze River Estuary

Knowledge about the spatiotemporal distribution of sea surface salinity (SSS) provides valuable and important information for understanding various marine biogeochemical processes and ecosystems, especially for those coastal waters significantly affected by human activities. Remote-sensing techniques have been used to monitor salinity in the open ocean with their advantages of wide-area surveys and real-time monitoring. However, potential challenges remain when using satellite data with coarse spatiotemporal resolutions, leading to a loss of valuable information. In the current study, based on the local dataset collected over the southern Yellow Sea (SYS), a region-customized algorithm was developed to estimate SSS by using the remote sensing reflectance. The model evaluations indicated that our algorithm yielded good SSS estimation, with a root-mean-square error (RMSE) of 0.29 psu and a mean absolute percentage error (MAPE) of 0.75%. Satellite-derived SSS results compared well with those derived from in situ observations, further suggesting the good performance of our developed algorithm for the study regions. We applied this algorithm to Geostationary Ocean Color Imager (GOCI) data for the month of August from 2011 to 2018 in the SYS, and produced the spatial distribution patterns of the SSS for August of each year. The SSS values were high in offshore waters and lower in coastal waters, especially in the Yangtze River estuary. The negative correlation between the monthly Changjiang River discharge (CRD) and SSS (R = −0.71, p < 0.001) near the Yangtze River estuary was observed, suggesting that the SSS distribution in the Yangtze River estuary was potentially influenced by the CRD. In offshore waters, the correlation between SSS and CRD was weak (R < 0.2), suggesting that the riverine discharge’s effect might be weak.

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