Past Members of the FAMER Lab

Richard Piola

Richard was a former research assistant with the lab and also completed an honours degree looking at the use of the Sydney rock oyster (Saccostrea glomerata) as an bioindicator of sewage effluent discharge into estuarine waters using stable isotope analysis.

The analysis of the stable isotopes of carbon (13C) and nitrogen (15N) of muscle, ctenidia and viscera of the Sydney rock oyster Saccostrea glomerata were used to trace the movement and assimilation of tertiary treated sewage effluent in the Manning River estuary, New South Wales. d15N values for the ctenidia and viscera of oysters from the sewage outfall location indicated the utilisation of 15N-enrich tertiary treated sewage effluent, discharged from the Dawson sewage treatment plant, as a nutrient source. Oysters immediately upstream and downstream of the outfall location were not enriched in d15N, suggesting that the effect of these effluent-derived nutrients on the estuary is relatively localised. This finding is supported by measurements of inorganic nutrient concentrations along the river. In addition to indicating the presence of sewage effluent, viscera significantly defined the presence of an ocean-to-estuarine gradient, proving it to be the most sensitive of the three tissues examined. However the high internal variability exhibited by viscera may prove it problematic for use in both tissue-specific and whole-body stable isotope studies. Results suggest that for a study of this scale ctenidia is the most useful tissue for characterising nutrient sources, as it was consistent in significantly defining the effluent discharge, it discerned the presence of the estuarine gradient, yet showed less internal variability than viscera. Muscle showed the least variability of all tissues, but was the least sensitive tissue to short term nutrient fluctuations, making more suited to larger scale long-term temporal and spatial investigations of nutrient sources.

Stephanie Moore

I completed my honours in 2000 examining the summer-time circulation of Jervis Bay and the zooplankton response. Observations of temperature and salinity for the summer period between 14 Dec 1999 and 30 Mar 2000 were used to examine the response of Jervis Bay to atmospheric cooling in the form of a diurnal air temperature cycle using a three-dimensional hydrostatic ocean model. The heat flux prescribed to the surface layer was based on meteorological observations for the corresponding sampling period. Model results demonstrated that diurnal cooling is sufficient to produce a density-driven circulation in Jervis Bay during summer. However, this circulation is sensitive to the offshore temperature field and to the magnitude of the diurnal air temperature cycle. Zooplankton samples were collected in conjunction with hydrographic observations. During upwelling, the zooplankton community was distinguished by a higher proportion of salps and the cladoceran Penilia schmackeri. After the upwelling period the zooplankton community returned to the pre-upwelling state distinguished by a higher proportion of the copepod Clausocalanus arcuicornis. The zooplankton community structure of Jervis Bay responded to the simulated currents in the bay and the modelled sewage distribution.

I began my PhD in 2001 investigating tracers and indicators of estuarine nutrients. The aim of this project was to develop water quality methods to assess nutrient flows under flood and low flow regimes, and thereby develop general tools for environmental rehabilitation. This proposal integrates water quality research by three government agencies, all with a long history of collaboration with UNSW (Department of Environment and Conservation, Department of Infrastructure, Planning and Natural Resources, Great Lakes Council). Methods of assessment of the biological response to water quality were developed and assessed over the austral summers of 2001 - 2002 and 2002 - 2003 for three southeast Australian estuaries; the Manning, Wallamba and Wallingat Rivers. The Wallingat River catchment is only 185 km2 and remains mostly unmodified, whereas the larger Manning and Wallamba River catchments are 8927 and 500 km2 respectively and support intensive livestock agriculture and some residential development. Phytoplankton dynamics and the stoichiometry, forms and fluxes of dissolved inorganic nutrients were investigated during dry baseline conditions and storm-related rain events. Strong vertical salinity gradients formed in all three estuaries following rain and inhibited the mixing of surface and bottom waters. The small unmodified Wallingat River regularly experienced periods of anoxia with dissolved oxygen observations were less than 0.5 mg L-1 when differences in salinity at the surface and at depth were greater than 5. Anoxia occurred along 15 km of this estuary and ammonia generated internally from decomposing organic matter in the sediments dominated water quality, reaching concentrations of up to 25 µmol L-1 in surface waters. In contrast, anoxic events in the Wallamba River were mostly limited to one site situated over an unusually deep hole and rarely occurred in the Manning River. Instead, water quality in the Manning and Wallamba Rivers was dominated by external, anthropogenic nutrient loads consolidated in runoff from their altered catchments. In spite of high concentrations of biologically available ammonia in the unmodified Wallingat River, phytoplankton biomass was low due to phosphate limitation, whereas phytoplankton biomass reached bloom concentrations of up to 58.5 mg chl a m-3 in the altered Manning and Wallamba Rivers.

The effect of advection and dispersion, nitrogen-limited phytoplankton growth and grazing by the mussel Xenostrobus securis after rain was investigated further using a coupled hydrodynamic-ecological one-dimensional box model for Wallamba and Wallingat Rivers. Nitrogen-limited phytoplankton growth and mussel grazing by X. securis on the inter-tidal lateral boundaries was forced by the transports approximated from a salt balance using salinity observations. The model captured important aspects of the temporal and spatial dynamics of dissolved inorganic nitrogen concentrations and phytoplankton blooms. A quantitative analysis of hydrodynamic and biological processes for the Wallamba River shows that increased phytoplankton growth due to elevated nitrogen loads after the rain event is not regulated by advective or dispersive losses alone. Instead, grazing by X. securis is quantitatively the most important process controlling phytoplankton biomass accumulation in the estuary. The intertidal mangrove pneumatophore habitat of X. securis allows filtering of the upper water column from the lateral boundaries in stratified conditions, exerting top-down control on phytoplankton biomass. In the Wallingat River, phosphate limitation prevented phytoplankton from reaching bloom conditions, and dissolved inorganic nitrogen released from sediments under anoxic conditions acted as a passive tracer.

The nitrogen and carbon stable isotope ratios (d15N and d13C) of X. securis as a long-term bio-indicator for the effects of anthropogenic catchment disturbance was investigated in the three estuaries. Manning and Wallamba River mussels were enriched in d15N by an average of 3.2‰ and 1.5‰ respectively compared to mussels from the unmodified Wallingat River. The isotope values of POM showed a similar pattern to mussels, indicating a direct link between them within each estuary. A multiple regression model of mussel d15N using the fractions of land used for livestock agriculture and residential development within 5 km zones from river networks to a distance equivalent to a tidal ellipse from sites explained 67% of the variation in mussel d15N with 95% of the differences lying within 1.6‰ of observed values. Increasing fractions of land used for livestock agriculture in the regression equation depleted estimated mussel d15N indicating the use of cow manure as a nutrient source with a value of 2.0‰. Whereas increasing fractions of land used for residential development enriched estimated mussel d15N indicating the use of human-derived waste with a value of 20.8%.

The optical plankton counter (OPC-2T) can provide an in situ, rapid assessment of the trophic status of water bodies from the size frequency distribution of zooplankton. The higher abundances of zooplankton in smaller size classes and of sub-resolvable particles, including suspended detritus, have hampered the use of the OPC in estuaries. A system to deploy the OPC in shallow estuarine systems was successfully developed allowing the OPC-2T to be used in an estuary for the first time over large temporal and spatial scales and the effect of coincident counts due to sub-resolvable particles was assessed. The size frequency distribution of zooplankton responded to the varying nutrient regimes of the three estuaries and may be an important integrator of phytoplankton blooms.

Matt Ives

Matthew has a broad range of experience from software development to economic analysis and environmental management. His primary focus is sustainable development which he has applied to a varied range of projects including cost-benefit analysis of overseas aid projects, developing sustainability indicators for forestry management, and building computer models for the sustainable management of harvested marine resources.

Matthew completed an Honours degree in Economics at UNSW in 1994 examining the economic cost-benefit analysis of air borne particulate matter from a coal gasification plant in Huangshi, China. After graduation Matthew utilised his environmental economics working for a number of years with an Australian Engineering and Project Management company conducting environmental and economic evaluations of overseas aid project in China.

Following this Matthew lived for a number of years in Portland, Oregon, U.S.A. where he worked as a software developer for a number of different companies while completing a Masters of Environmental Management part time at Portland State University. For his Masters Thesis Matthew worked with the U.S. Forest Service for a number of years developing their LUCID sustainability indicators (

Currently Matthew is completing a PhD looking at fishery management strategy evaluation for penaeid prawn species in NSW with the Department of Primary Industries (formally NSW Fisheries). This project involves developing computer models of prawn harvesting strategy based on catch and effort data of prawn harvests in NSW. Alternative models will be assessed against the data using Bayesian Techniques. Once the model(s) are fitted to the data and tested they will then be used to conduct management strategy evaluations. This will involve running the model(s) against simulated data to determine the impact to the fishery of alternate management strategies. The work will concentrate on two species of prawn, the Eastern King Prawn (Penaeus plebejus) and the School Prawn (Metapenaeus macleayi) which together constitute the most important harvested species in NSW waters.

Kelly Wright

Kelly completed her Honours in 2002 examining the contribution of a bird rookery to an estuarine nutrient budget. Guano from bird rookeries may provide a significant source of nutrients in estuaries, particularly for ecosystems already under nutrient stress from agricultural run-off and sewage. Pelican Island, a 500 m2 sandbar island in Wallis Lake on the mid north NSW coast became a roosting site for pelicans, cormorants, terns, gulls and swans in 1980-1983, and currently has a population of 300 – 500 birds. Significantly higher ammonia and phosphate concentrations were found in waters surrounding Pelican Island than waters 2 km away from the island. Further, increased algal growth occurred on settlement plates deployed near to the island after a period of 10 days, compared to plates deployed 1 – 2 km away. At two sites where swans were abundant, the stable isotopic signature of the seagrass Posidonia australis was similar to the signature of swan guano. The pygmy mussel, Xenostrobus securis, exhibited significant changes in d15N and d13C over a two month mooring deployment near the island, which was not related to Pelican Island. These isotopic signatures are likely due either to anthropogenic nutrient sources, including dairy nutrient run-off or terrestrial sources. I estimate that the bird colony contributed <1% of nutrients to the lake compared to the catchment load. However, the potential exists for a significant contribution of nutrients from a bird colony in an estuary one tenth the area of Wallis, with enhanced water residency as in a closed lagoon, or if the population should return to previous levels of >800 pelicans.

Kelly has since started a PhD. with the FAMER facility in conjunction with the Australian Museum looking at the ontogeny of behaviour and sensory abilities in larvae of marine fishes. Traditionally the dispersal of marine larval fish was thought to be passive, with currents and the duration of the pelagic larval stage controlling distributions (Leis, 2002). Sensory abilities of larval fishes were considered limited (being developed sufficiently for feeding only). However, recent research has shown that by the end of their pelagic stage, marine fish larvae are behaviourally competent with well-developed sensory abilities. Late pelagic larvae are able to detect both smells and sounds originating from a reef and can orientate in the pelagic environment (Arvedlund et al., 1999; Tolimeiri et al., 2000). Further, these late stage larval fish are competent swimmers, able to control their trajectories and thus avoid passive dispersal (Stobutzki & Bellwood, 1997; Leis & Carson-Ewart, 1999). However, little is known about the timing and development of these abilities in larval fish. The aim of this project will be to examine the ontogeny of auditory and olfactory abilities relevant to dispersal of marine fishes. Field and laboratory work on morphology, sensory physiology and behaviour of several species throughout their ontogeny will utilize reared and wild individuals. The outcome of the project will be the understanding of when during the larval phase fish are able to actively modify dispersal patterns, information vital for management of marine living resources and design of marine reserves.

John Ford

John is currently completing an Honours degree examining larval fish recruitment in Wallis lake and Lake Macquarie.

Juvenile fish are often patchily distributed in seagrass beds, due to either plankton and the pre-settlement stages accumulating in low tidal velocity zones resulting in preferential settlement, or due to post-settlement survival. The abundance and condition of juvenile fishes will be compared among areas of Wallis Lake and Lake Macquarie, as predicted by particle accumulations in flood-tide simulations of high resolution (<100 m) circulation models. Some particle accumulation zones may contain more planktonic food, supporting higher larval condition. We will test if circulation models provide a general tool for predicting recruitment hot-spots, for enhancing local fisheries, and for protecting key areas from development.

Troy Gaston

In 2002, Troy completed his PhD at the School of Biological, Earth and Environmental Sciences at the University of NSW. The aim of the PhD was to attempt to determine nutrient sources of pelagic food chains in urban coastal waters, based on the analysis of stable isotopes of carbon and nitrogen.

A fundamentally different pelagic food chain exists off the coast of major Australian cities, based on the relatively large and persistent flow of sewage from ocean outfalls. This chronic discharge on an otherwise nutrient-poor and sporadically enriched ecosystem off Sydney is a drastic disturbance and may cause eutrophication and plankton blooms. Alternatively, it may productively enter the fishery. Together with local oceanography, the contribution of these nutrients to planktivorous fish will be determined using the naturally occurring stable isotopes of carbon (13C) and nitrogen (15N) as tracers of anthropogenic input. There is a significant difference in isotope composition of fish tissues between impacted and non-impacted regions along the NSW coast. This spatial variability is based upon the consistent difference in muscle and liver tissue between Sydney (impacted), which is significantly depleted in 15N, relative to Port Stephens (non-impacted) and Jervis Bay (non-impacted). Sewage particulate matter is also significantly depleted in 15N, relative to oceanic particulate matter. These tissues represent a time-integrated measure of dietary source, suggesting that there is a different nutrient source making a significant contribution to the Sydney coastal food chain.

A high-resolution temporal study of estuaries from an impacted (Sydney) and a non-impacted (Port Stephens) region was able to classify the stable carbon (13C) and nitrogen (15N) isotope signature of estuarine organic matter. A mixing model was also develop, outlining the relative importance of each of these nutrient sources to the coastal pelagic food chain.

Troy has recently accepted a position as a Senior Technical Officer at the University of the Sunshine Coast, Queensland.

Jocelyn DelaCruz

Jocelyn has recently completed a PhD looking at the growth and biology of a red tide forming dinoflagellate, Noctiluca scintillans, in response to chronic anthropogenic nutrient inputs.Jocelyn's work provides a detailed account of the population dynamics and ecology of Noctiluca scintillans along the south-east coast of Australia.

Over the past decade red tides have drawn considerable attention from both the scientific and public community since there has been an apparent increase in the frequency and intensity of red tides on a local and global scale. In south-eastern regions of Australia, the red tides have been so extensive that many beaches were closed during peak holiday times. There has been some public concern that the red tides may be due to chronic discharge of effluent from the three large offshore deepwater outfalls off Sydney. Factors such as increasing public awareness and scientific research, improved analytical and sampling methodology and natural changes in climate, may confound some of the information currently available. Some studies have correlated an increase in the occurrence of red tides with eutrophication, while others have suggested seasonal changes in temperature, light and salinity are the dominant causative mechanisms that effect the population growth of Noctiluca.

Jocelyn has recently accepted a Post-Doctorate position based at the University of Plymoth, United Kingdom.

Dom Clarke

Domine completed her honours degree with the lab in conjunction with Dr Jeff Leis of the Austrealian Museum in 2002. Her project was looking at the ontogeny of swimming performance in the larvae of two temperate marine fish species: Argyrosomus japonicus and Pagrus auratus.

The critical swimming speed and endurance swimming performance of reared larvae of A. japonicus and P. auratus were examined using a laboratory swimming chamber. Critical swimming speed tests increase the current speed in the chamber incrementally; whilst endurance tests use a selected current speed (in this case, 10 cm s-', the average ambient current speed on the continental shelf off Sydney). In both tests, larvae were swum until they fatigued. Swimming performance increased with age, size and propulsive area in larvae of both species. The propulsive area of the larvae was the morphological characteristic that best explained variation in swimming performance. At sizes > 6.8 mm the critical speed of the larvae places them in the inertial Reynolds number regime, meaning swimming is relatively efficient. Settlement-stage larvae (> 9 mm (SL)) swam an average of 6.2 - 6.9 km in endurance tests and an average of 15 - 25 cm s-' in critical speed tests. Swimming at speeds equal to average ambient current speeds began at the development half-way point of the pelagic larval phase both species. From that stage, these larvae have the potential to directly affect their dispersal by horizontal swimming, which is an important consideration in modeling transport pathways of larval fish from spawning site to settlement location. Swim bladder inflation had a positive significant effect on larval swimming performance; whilst high larval stocking densities had a negative significant affect on larval swimming performance. Larval condition, as measured by morphological indices, did not have a measurable effect on swimming performance. Morphology, with respect to propulsive area, was found to be a more important influence on swimming performance than were habitat (tropical versus temperate), or taxonomic differences. Comparison of results obtained by laboratory and in situ methods of studying larval swimming abilities found them to be highly correlated and complementary.

Jenny Giles

Jenny completed her honours degree with the lab in 2002 looking at the roles of salinity and predation on the size structure and distribution of the pygmy mussel Xenostrobus securis.

Spatial change in population size structure of the pygmy mussel Xenostrobus securis was correlated to the salinity gradient along two rivers in the Wallis Lake Estuary, New South Wales. Small mussels dominated upstream sites, while a more even distribution of mussel size classes characterised the sites further downstream over a five month sampling period. Differential recruitment and growth with salinity explained the majority of variation observed in space and time. Predator exclusion experiments identified fish as predators, however there was no difference in predation incidence along the salinity gradient or in different estuarine substrates. Common toadfish Tetractenous hamiltonii ate more 5 mm than 10, 15 or 20 mm mussels in a laboratory study, suggesting that size specific predation may have an effect on length class distributions of X. securis in Wallis Lake. Estuarine circulation and salinity regime may be important determinants of the roles of recruitment and growth in structuring X. securis populations. Interspecific competition for space is proposed as a mechanism for the downstream distribution limits of this species.

Augy Syahailatua

Augy completed a PhD. with the lab in 2002 looking at signature larval ichthyoplankton assemblages as tracers of upwelling events.

Two cruises were conducted in the East Australian Current (EAC) and throughout a topographically induced upwelling zone off eastern Australia in November 1998 and January 1999. Ichthyoplankton was sampled at the surface and in sub-surface waters at 50 m and 100 m isobath stations. From the 113 families we found no significant difference in the total abundance nor diversity of larval fishes between regions within or upstream of the upwelling. In both months we found the standardised abundance of Carangidae, Scombridae, and Lutjanidae associated with the EAC water mass, while the Callionymidae, Platycephalidae, Sillaginidae, Bothidae and Clupeidae were mostly found in the upwelled water mass.

Opportunistic sampling of a separate wind-induced upwelling confirmed our taxonomic findings. The family-specific signature assemblages of upwelled and EAC waters provided a basis for assessing mixing of water masses. At the taxonomic scale of family, and spatio-temporal scales of kilometres-days, larval fish assemblages are a tool for identifying the water mass and mixing. Besides adult spawning patterns, assemblage composition could also be influenced by mixing, dilution and differential mortality.

Antwanet Kostaglidis

Antwanet completed an honours degree in 1999 looking at the stable isotope signatures and condition of the eastern hula fish, Trachinops taeniatus.

The eastern hula fish was collected from three regions along the NSW coast, each with different levels of sewage effluent input - primary (Sydney), secondary (Port Stephens) and tertiary (Jervis Bay). Each region consisted of an outfall site and two non-outfall/reference sites.

Sewage transported in to aquatic environments has characteristic isotopic signatures differing from marine and estuarine food sources. Stable isotopes have been used successfully in the past to establish casual links between the sources and sinks of organic matter.The carbon and nitrogen stable isotope analysis was performed on hula fish tissue to provide information on nutrient sources of the hula fish. Carbon and Nitrogen isotopic values revealed a different source of nutrients at some outfall sites compared to reference sites. Condition indices (Fulton's K and gut fullness) of the hula fish were compared to determine if there were any significant differences in the condition of the hula fish over time, among regions and among sites.

By combining the use of stable isotope analysis and condition indices, hula fish were found to be a useful indicator of coastal eutrophication.

Kimberley Smith

Kim Smith completed her PhD with the Fisheries & Marine Environmental Research facility in 2000. Her PhD research focusd on the ecology of larval and juvenile fish, and how they relate to the physical environment. Fish larvae are very small (mm's in length) and relatively poor swimmers, so they tend to drift with currents. For example, tropical larvae from the Great Barrier Reef are sometimes found off Sydney after being transported southwards by the East Australian Current. In general, unfavourable currents can transport fish larvae into ocean regions that may not support their growth or survival. This has major implications for fisheries management. Variations in year class strength (i.e. the number of young recruits each year) of many fish stocks is strongly influenced by the number of larvae finding enough food to survive or successfully being transported to juvenile nursery grounds. With sufficient knowledge of ocean currents and larval behaviour, spatial and temporal recruitment patterns can often be predicted.

Surveys of larval fish were conducted in continental shelf waters off Sydney. Larvae were sampled by plankton net hauls from a large research vessel, sampling to depths of 120 m and distances of 40 km from shore. Larval distributions were related to current patterns and temperature/salinity properties of surrounding ocean waters. It was found that some species drift relatively passively with currents, but others undergo vertical and horizontal migrations to counter the effects of currents.

Other research included monitoring of recruitment patterns of fish larvae into Sydney seagrass beds. Many fish species which occur in estuaries spawn in the ocean and have planktonic marine larvae. Larvae enter estuaries just prior to metamorphosing into juveniles and settling from the plankton into seagrass beds (or other bottom habitat). How such tiny larvae achieve this is not fully understood. Many make use of tidal currents, resulting in regular 'pulses' of recruitment. Other factors which determine the timing and magnitude of recruitment events include ocean currents (delivering larvae from ocean to estuary entrance) and the vertical and horizontal swimming behaviour of larvae. Newly settled juveniles in seagrass can be sampled by use of a beach seine net of small (mm) mesh size. Frequent sampling can yield details of the timing of settlement, which can then be related to the timing of meteorological and oceanographic events to suggest which might be important to the settlement process. Such information furthers our understanding of, and our ability to predict, recruitment variability.

Kim is currently employed as a research scientist at the Waterman’s Research Laboratories, Fisheries WA, in Perth.

Michael Lowry

Michael completed a PhD. in 1997 looking at the biology and ecology of the red morwong (Cheilodactylus fuscus).

The diverse and abundant rocky reef fish community off south eastern Australia is virtually unstudied compared to similar reefs off New Zealand and South Africa, or the tropical reefs of the Great Barrier Reef. One particular species, the red morwong (Cheilodactylus fuscus) dominates the fish community of the temperate rocky reef habitat off south eastern Australia, and is popular with SCUBA divers and spearfishing enthusiasts. Information detailing movement patterns, reproductive ecology and age structure were clear research priorities in assessing the potential of this species as a bio-indicator.

An understanding of the behavioural ecology of cheilodactylids has been limited by the resolution of previous studies. The ability to accurately track the movements of individual fish using ultrasonic transmitters and external dart tags was essential in determining a comprehensive understanding of behaviour and demonstrates how estimates of habitat specificity and movement patterns based on day observations alone may give misleading results. The tagging study indicated a limited home range with a significantly different mean night (3639 m2) versus day (1865 m2) estimates. Night and day comparisons indicated diel variation in habitat use. Fish were restricted to the bouldered habitat during the day and moved over a broader range of substrate types at night to feed. Activity patterns also varied with crepuscular peaks in the distance moved.

The band structure of thin sectioned otoliths revealed that this species is long lived with a mean age of 6.2 years and a maximum age of 40. Marginal increment analysis and tetracycline validation determined that bands are formed annually during winter and spring. Relative ovary weight (GSI) and histological examination of both ovaries and testis indicated that this species is gonochoristic with a peak in reproductive condition during autumn and winter, with mature females spawning more than once over the peak reproductive period and males maintaining viable gametes over a longer period.

C. fuscus populations are structured by persistent aggregations of 3 to > 100 fish maintained by the same individuals in the same location for extended periods of time. Aggregations are located exclusively on bouldered substrata and differ significantly in their size and sexual composition. An analysis of 29 habitat variables of existing aggregations and similar unoccupied control sites failed to resolve the factors that determine the location of aggregations.

This work has indicated similarities between other members of the genus, providing an important basis on which to asses the ecology of similar species. Results of this study have provided the information required to more accurately interpret and manage the impact on areas of reef associated with urban development and aid in the management of temperate reef in general.

Brett Law

Brett completed honours in 1996 looking at microzooplankton size distribution in New South Wales coastal waters as an effect of eutrophication.

The responses of the microzooplankton community were investigated in the eutrophic waters off Sydney, in comparison to control transects off Port Stephens and Jervis Bay (NSW, Australia). Changes in the microzooplankton particle-size distribution and community structure were associated with sewage effluent discharged from Sydney. A manipulative experiment in mesocosms treated with fertiliser or secondary effluent showed significant increases in microzooplankton abundance, biomass and a clear change in particle-size distribution relative to the control treatments. Image analysis enable measurements and identification of the most abundant particles indicating a change in planktonic community with the naked dinoflagellate Noctiluca scintillans, copepods and larvaceans becoming more predominant with increasing eutrophy. Similar changes in particle-size distribution and community structure were found across the continental shelf off each region. Three distinct community types were identified; nearshore, midshelf and offshore. Along shore comparison among the three regions found no evidence of a "Sydney effect" due to a large upwelling event off Jervis Bay which had a significantly greater effect on plankton abundance. This indicated that while anthropogenic nutrients may enhance microzooplankton biomass locally, a single upwelling event may overwhelm the nutritional effect of sewage discharge. A conceptual model was devised that represents the change in particle size distribution as a tool to determine response to increasing nutrient levels.

David Rissik

Dave completed a PhD. in 2000 looking at the response of zooplankton to perturbations in nutrients of different origins using particle size analysis.

Nutrient limitation is the major cause of Australia's oligotrophic oceans and her scant fisheries. Consequently, the response of zooplankton due to natural or anthropogenic sources of nutrients should be dramatic. By using automated plankton counters and the size-frequency distribution of zooplankton, I investigated the response by zooplankton to nutrient perturbation in three regions off eastern Australian.

The effect of flow disturbance (0.3 m.s-1) around an isolated, steep sided reef, in the south Coral Sea caused doming of isotherms by 20-30 m in the flow disturbed region at the north western side of the island. Chlorophyll and nutrients were 1.4 times greater in the disturbed region. All particle size classes were more abundant in the flow disturbed region than in the free stream, but abundance was relatively greater for small plankton due to increased production by smaller zooplankton. The relative composition of zooplankton did not differ between regions and was dominated by the calanoid copepods Pleuromamma and Acartia, and the cyclopoid copepod Oncaea. The particle size community was not significantly different within or between nights, but most flow disturbed stations were significantly different from the free stream stations.

The feeding success of post larvae and juveniles of two myctophid fish (Diaphus kapalae and Myctophum sp.) was greater in the disturbed region than in the free stream. Gut fullness was significantly related to the concentrations of small sized zooplankton (Diaphus kapalae r=0.63, p<0.05 and Myctophum sp. r=0.55, p<0.05). Similar sized Diaphus kapalae and Myctophum sp. within a region, consumed a different particle size community, probably enabling them to co-exist. Island induced disturbance appeared to be an important contributor to the pelagic food web, and ultimately the 300,000 ton pa yellow-fin tuna fishery.

Experiments using three treatments over six mesocosms (fertiliser, secondary treated sewage and controls) were conducted to calibrate results from field experiments. Phytoplankton responded rapidly (>1000 cells 1-1.d-1) over the first three days following nutrient addition, while zooplankton biomass increased slowly (0-1.1 mg.l-1.d-1). Zooplankton increased significantly between three and six days (2-4 mg.l-1d-1) while phytoplankton rates of increase fell to < 100 cells l-1.d-1 in the first summer experiment and < 500 cells l-1.d-1 in the second. Zooplankton changes were dominated by small size classes (100-250 um esd), corresponding to the sizes of copepod nauplii, and tintinnids. Data indicated that zooplankton size and the ambient temperature of the water are important determinants of the rates of zooplankton responses.

Sporadic upwelling events occur off the New South Wales coast each summer, caused by eddy encroachment onto the shelf or by persistent north-easterly winds. Across the shelf in three regions (off Sydney, Port Stephens and Jervis Bay) nutrient concentrations were higher in areas of cooler water indicating that upwelling had occurred. Concentrations of chlorophyll a, the slopes of the zooplankton size frequency distribution plots (an indicator of recent' increased production) and zooplankton biomass, were higher in cooler water. Zooplankton abundance was related to chlorophyll concentration (r=0.73, p<0.01). Following upwelling off Port Stephens, biomass increased at stations with the highest nutrients. Slopes increased initially indicating recent production and over time slopes decreased together with a comprehensive increase in biomass.

Dave is currently the estuaries manager at the New South Wales Department of Infrastructure, Planning and Natural Resources (DIPNR).

Lara Manarangi-Trott

Lara completed an honours degree in 2000 looking at the age and growth characteristics and the effects of fishing pressure on maito (Ctenochaetus striatus), a tropical reef fish, in Rarotonga, Cook Islands.

Marine reserves may provide many benefits to harvest fish populations, including increases in abundance and size of fish, and export of juvenile and adult biomass to surrounding fishing grounds. In Rarotonga, Cook Islands, the effect of a lagoon marine reserve (Raui) on the size distribution and abundance of Ctenochaetus striatus (maito) was assessed using underwater visual census techniques. The Raui was shown to have no effect on the density of the dominant size classes of maito, but there was a significantly higher density of the largest maito in the Raui, which suggests increased longevity due to protection. Juvenile and sub-adult maito were found in the lagoon and reef flat habitats, while adults were found on the reef slope.

The age and growth characteristics of maito outside the Raui in Rarotonga,Cook Islands, were determined using sagittal otoliths. Maito were found to have larger maximum size, lesser longevity and slower rates of growth relative to other regions within the South Pacific. This can be attributed to variations in sea surface temperature, and possibly also fishing pressure. The results suggest that changes in may need to be made to Raui, such as increased designation length, to benefit maito and other fish with similar growth patterns. In addition, the natural variations in age and growth of maito should be understood before determining the effects of fishing pressure.

Edward Ho-Shon

Edward completed his Honours in 1999 looking at the assimilation of stormwater nutrients by calanoid copepods in urban lagoons in Sydney, NSW.

Manly and Curl Curl Lagoons are highly affected by urban development and some industrial activity. Dee Why Lagoon is mainly affected by urban development. Two calanoid copepods were focused on as these were dominant species within the lagoons and present both before and after rainfall, Acartia bispinosa in Dee Why and Curl Curl Lagoons and Paracalanus aculeatus in Manly Lagoon. A different copepod was needed for Manly Lagoon as Acartia bispinosa was present only in very low densities prior rainfall and not at all after ranfall.

Copepods were collected on three occasions before rainfall and 6 occasions after. Temperature, salinity and nutrient data was also analysed. Two major stormwater point sources were chosen in each lagoon. Nitrogen and Carbon stable isotope ratios were determined for adult copepods and stormwater particulate matter. An additional laboratory experiment was conducted to determine changes in stable isotope composition of copepods fed diets that were known to have a different isotopic signatures, under low and high salinity regimes.

Dee Why lagoon showed the clearest response to nutrient influx. Phytoplankton was seen to increase a few days after nutrients increased. This was followed by increases in the abundance of copepods, particularly juvenile stages. Stable isotope analysis revealed nutrients entering the food chain, with changes in carbon stable isotope ratios in copepod tissues recorded 2-4 weeks after rainfall. These patterns were not observed in Manly or Curl Curl lagoons, possibly due to Manly Lagoon being connected to the sea and undergoing regular flushing and Curl Curl lagoon being flushed during the middle of the sample period. The population structure of Acartia bispinosa changed after rainfall in Dee Why Lagoon. Carbon stable isotope ratio of adult Acartia bispinosa was found to change after rainfall in Dee Why Lagoon. The turnover rate of nutrients in Acartia bispinosa was found to be highest at low salinity and high food concentrations.

Joanne Bennett

Joanne completed an honours degree in 2001 looking at the ecology of dolphin fish (Coryphaena hippurus) off the coast of NSW using tag and release data-sets.

Dolphin fish are a worldwide tropical species of pelagic fish the occur in Australian waters. Using a 20 year tag and release dataset containing 14,000 records, the occurrence of dolphin fish was inferred along the NSW coast, between 30 and 36 degrees south. There is a seasonal movement of dolphin fish down the east coast of Australia off NSW when sea surface temperatures (SST) are elevated. Tagged fish that were recaptured in summer and early autumn indicated a southerly, with a northerly movement evident in autumn and winter. Twenty (20) degrees Celsius was found to be the lower limiting temperature for dolphin fish but a preference for waters greater than 22 degrees Celsius was exhibited.

The size-structure of the population was mixed with no discrete size groups in space or time, although increases in the modal length were observed between seasons within the regions sampled. Environmental variables appear to influence the size-structure of the population, in particular the SST in the tropical western Pacific of the previous year and ENSO variations.

Key issues associated with recreational tag and release data-sets include biological characteristics of the species, timing and location, growth rates, schooling behaviour and life span. Aspects of the fisheries are also important, such as the spread and evenness of recreational fishing in space and time. Other aspects of the data that need to be considered are the lack of information on fishing effort, the incidence of multiple tagging events and the assumption of random sampling.

Inger Shimell

Inger completed an Honours in 1999 looking at the temporal abundance patterns of the red tide forming dinoflagellate, Noctiluca scintillans and crustacean zooplankton.

The temporal abundance pattern of Noctiluca scintillans and crustacean zooplankton was examined in Bate Bay, NSW in four months over the spring/summer period of 1999. The overall pattern of abundance of Noctiluca was comparable to the patterns observed in previous studies in the area.

The abundance of Noctiluca varied significantly at the scale of days and weeks and was linked to phytoplankton availability and possibly salinity change. The abundance of total crustacean zooplankton did not vary significantly on a monthly or daily scale, but did exhibit changes between weeks. The abundance of crustacean zooplankters did not appear affected by fluctuations in chlorophyll-a levels. There was found to be no correlation between the abundance of Noctiluca and the total abundance of crustacean zooplankton. However, the abundances of some dominant crustacean taxa such as the copepods Paracalanus spp. and Acartia spp and cladocerans, (Penilia sp. and Evadne spp) correlated with the abundance of Noctiluca.

The total zooplankton assemblage was most strongly influenced by changes in individual taxa over months, and not by variation in Noctiluca numbers or the total abundance of crustaceans . The zooplankton assemblage and the abundance of all taxa analysed varied significantly between the two sampling times of 1:00 and 4:00 AM, most likely the result of tidal flow and diel vertical migrations of the crustacean zooplankters. Predation by Noctiluca on copepod eggs in the study area is unlikely to affect the abundance of adult copepods as percentages of ingested to total copepod eggs never exceeded 9%.

Adam Smith

Adam completed a PhD. in 1998 looking at the effect of sewage effluent on rocky reef fishe in New South Wales.

Underwater visual surveys were conducted at ocean sewage outfalls and multiple control locations within the Hunter, Sydney and Illawarra regions on the central coast of New South Wales. In the Hunter region, however, a Before/After/Control/Impact (Beyond BACI) experimental design could be used, providing an optimal design to detect the effects of sewage pollution contrasted against natural spatial and temporal variability in fish and a sea urchin. Both the Illawarra and Hunter studies indicated that sewage has significant impacts on assemblages and populations of rocky reef fish and selected macrobenthos. General patterns identified were greater abundances of Cheilodactylus fuscus (Cheilodactylidae), smaller abundances of Trachinops taeniatus (Plesiopidae), Hypoplectrodes mccullochi (Serranidae) and the sea urchin Centrostephanus rodgersii at outfalls compared to control locations.

A survey of the status of fish populations following the shutdown of a large sewage outfall in the Sydney region also indicated that fish assemblages had been significantly different at the outfall compared to control locations. It also provided information on "recovery" over a 13 month period. For example, large numbers of Acanthopagrus australis (Sparidae) were observed at the outfalls but declined after about 10 weeks.

Data on species abundance are by far the most commonly used for environmental studies, but biomass data can also provide useful information. Biomass was estimated from data at the three regions and sewage outfalls generally contained less fish but a greater biomass than the controls.

Cheilodactylus fuscus, Parma microlepis (Pomacentridae) and Trachinops taeniatus, were consistently more or less abundant adjacent to outfalls compared to controls. These species were collected from outfall and control locations in the Sydney region to investigate impacts on fish condition that could be attributed to sewage pollution. C. fuscus and P. microlepis occurring adjacent to sewage outfalls had a greater proportion of unhealthy liver tissue and greater gonadosomatic indices compared to controls. A comparison of C. fuscus collected in the 1980s with the present study indicated a 10% increase of liver index. The mean total length of T. taeniatus was consistently smaller from one outfall location. Female T. taeniatus from outfalls had a larger number of eggs and smaller diameter of eggs than fish from control locations. A caging experiment was conducted, and although mortalities of up to 73% of T. taeniatus per cage were recorded at one outfall, there was no overall significant mortality due to sewage.

The surveys of fish at three regions in NSW suggest several bioindicators that could be used to measure the effects of sewage pollution. They also suggest a model for predicting the ecological impacts of sewage on rocky reef fish assemblages.

Patrick Driguez

Patrick completed an Honours in 1999 looking at the growth of larval fish in nearshore NSW waters, using otolith microstructure analysis and stable isotope data.

To determine if larval fish from the heavily sewage impacted nearshore waters of Port Hacking, Sydney had a growth advantage over the less impacted waters of Port Stephens and Jervis Bay, a field study was conducted over six time intervals between December 1998 and January 2000 measuring the abundance, growth rate, and carbon and nitrogen stable isotope value of clupeiform larval fish from these regions. Species diversity and density, and isotope ratios were used to spatially distinguish any growth differences measured from otolith microstructure. Temporal and regional differences in these parameters were detemined with a range of non-parameteric and parametric analyses. In addition, environmental variables and oceanographic data were used to interpret the results.

My study suggests that a combination of environmental and oceanographic variables including temperature, wind, ocean currents and slope water intrusions provide some explanation for larval fish density, species diversity, growth rate, and isotopic variability. Density and isotope ratios suggest larval fish might be associate with distinct transient water bodies during times of high oceanic activity. Sydney waters had no growth advantage compared to low sewage impact waters. Growth rate differences in Engraulis australis larvae appeared to be the result of oceanographic variability and not necessarily due to sewage discharge.

Brooke Newell

Brooke completed her Honours in 1999 looking at the changes in zooplankton community structure following nutrient enrichment associated with heavy rainfall in urban coastal lagoons.

Increasing urban activities, including industrial and residential growth have led to increased rates of nutrient enrichment in many urban estuaries. Nutrient enrichment is often greatest in urban estuaries after heavy rainfall. Heavy rainfall can transport nutrients from catchment areas into these systems via creeks and stormwater drains. In NSW nutrient enrichment is most commonly a problem in the summer time when heavy rainfall is greatest and water temperatures and light penetration are also high ensuring rapid biological responses to increased nutrients. In response to increased nutrients in the summer time greater rates of primary production by phytoplankton can occur. This has become evident by the greater occurrence of algal blooms in urban estuaries.

The first aim of this study was to assess nutrient loads and phytoplankton abundance in Manly and Dee Why lagoons before and after heavy rainfall. The second aim was to investigate any changes in zooplankton size structure and species composition within each lagoon after heavy rainfall. Thirdly, responses of zooplankton size structure and species composition to heavy rainfall in each lagoon were compared between the two lagoons. If nutrient loads and phytoplankton abundance increased and zooplankton size structure changed after heavy rainfall a fourth aim was to investigate the affect of increased nutrients on zooplankton size structure in a controlled laboratory experiment.

In Dee Why lagoon, nitrogen nutrient concentration increased at the onset of rainfall, concurrent with this phytoplankton and nauplii abundance increased and 5 days later when the abundance of smaller zooplankton decreased the abundance of large zooplankton increased suggesting growth of the naupliar cohort. This is consistent with the results from the lab expt that showed an immediate increase in smaller particles followed by an increase 5 days later in larger zooplankton. In Dee Why lagoon it appears that zooplankton grazing is able to limit primary production after nutrient enrichment

In Manly lagoon, the concentration of nitrogen nutrients also increased. However despite the much greater increase in Manly lagoon compared to Dee Why lagoon the abundance of phytoplankton and zooplankton was less in Manly lagoon. This is most likely a result of the exchange of water between the lagoon and the ocean after rainfall. The high abundance of phytoplankton found prior to rainfall suggests though that if heavy rainfall had not unblocked the pipes a potential phytoplankton bloom may have occurred. The higher concentration of nitrogen nutrients in Manly lagoon and the high abundance of phytoplankton before rainfall suggest that management strategies for this lagoon should be investigated.

Tim Dempster

Tim completed his Marine Science honours at the University of NSW in 1994. The topic of his honours was the dynamics of surface ichthyoplankton on the Sydney shelf.

Variability in the distribution of ichthyoplankton is extensive and often unexplained, thus confounding environmental monitoring programs and impact studies (e.g. Gray et al., 1992). This study related the variability in the surface ichthyoplankton on the Sydney shelf with detailed oceanographic measurements from a concurrent study.

Ichthyoplankton sampling was conducted in January and April 1994 on board the CSIRO's oceanographic research vessel, Franklin. All sampling was undertaken at night across 5 stations (A-E) representing an inshore-offshore transect traversing the continental shelf off Sydney. Replicate tows of the surface waters (0-2 m) were made using a plankton net. Three complete A-E transects were performed on three separate nights in January (22/1, 23/1, 25/1) and in April (5/4, 6/4, 8/4) to assess between night variability. Within night variability was examined at stations B and C on April 9.

In January, total abundance was highest at stations A, C and D, with lower numbers at stations B and E. Family diversity decreased markedly from inshore to offshore. The dominant taxa exhibited strong cross-shelf patterns; pomacentrids and carangids decreasing in abundance from inshore to offshore, myctophids and gonostomatids increasing from inshore to offshore. In April, total abundance and family diversity increased from inshore to offshore, a trend reflected by the four dominant taxa; gonorhynchids, berycids, serranids and myctophids. The cross shelf patterns in January and April are related to adult spawning time and location.

A small but consistent temperature and salinity difference between stations B and C in April, indicates the possible presence of a coastal boundary layer off Sydney. In January, hydrographic conditions were variable across the shelf and formed no distinct cross shelf pattern.

Significant within night variability occurred on April 9, manifesting as shifts in the relative abundance of dominant taxa in surface waters. At station B, an increase of berycids during the night was countered by a decrease in the number of carangids, effectively dampening an increase of the total abundance of fish larvae. Myctophid and serranid abundance significantly increased in the surface waters at station C during the night, causing an increase in total abundance. Either diel vertical migration or the internal tide was responsible for the significant changes in the abundance of taxa. This study was not able to differentiate the effects of these two processes.

Considerable between night variability at each station occurred in both January and April. Current meter data from a concurrent oceanographic study allowed the generation of the cross-shelf current flow structure during the sampling periods. Surface mixed layer advection accounted for a significant amount of the variability observed in January, particularly at the inshore stations. The appearance of pomacentrids in large numbers at station A on night 2 was consistent with an offshore current flow. Surface temperature, salinity and fluorescence and the stratification parameter delta-Sigma-t were consistent with offshore advection. Between night differences in the abundance of carangids in January can be related to the presence of a convergence zone, consistent with the opposing cross shelf current flows established by the passage of a coastally trapped wave. Myctophid and gonostomatid variability on the outer shelf was not related to cross-shelf currents and biological influences may be important in determining their distribution.

In April, little current meter data was available. Hydrographic conditions were consistent with a possible onshore advection of water on night 3, reflected by an increase in the abundance of the berycids, serranids and myctophids.

Oceanographic processes clearly influence ichthyoplankton distribution on the Sydney continental shelf on the scale of between nights. Without adequate measures of large scale oceanographic dynamics, a large amount of ichthyoplankton variability will remain unexplained or be incorrectly linked to biological and environmental factors.

Rebecca Chapman

Rebecca completed her honours degree with the lab in 1998 looking at the fluctuating asymmetry in the otoliths of the eastern hulafish (Trachinops taechinatus) as a potential indicator of environmental stress.

Fluctuating asymmetry (FA) - random deviations from perfect bilateral symmetry as a result of developmental perturbation - has been used as a measure of the capacity for stable development in populations exposed to a variety of genetic and environmental stresses. In the present study, FA in area and perimeter of the sagittal otoliths was used to compare stressed and control samples of the eastern hulafish (Trachinops taeniatus, Plesiopidae) in both field and laboratory studies. Field samples were collected in the vicinity of and away from cliff-face sewage outfalls, previous work having shown significant reductions in hula size and abundance at outfalls compared to control sites. In the laboratory, stressed fish were exposed to osmotic fluctuations while controls were maintained at constant salinity. No significant differences were found between stressed and control groups in either component. When pooled by treatment, stressed laboratory populations showed consistently higher FA than controls, but this pattern was confounded by high between-tank variability. Possible selective mortality was suggested by higher FA in fish that died, and by a slight (though not significant) decline in FA over the three months of the experiment.

The lack of significant differences between treatments, as well as the low levels of asymmetry found (on average 1-2 % of trait size), suggest that FA in otolith area and perimeter may not be a sensitive indicator of environmental stress for this species. Since the otoliths play a vital role in the maintenance of balance and orientation, their susceptibility to developmental disturbance may be limited by strong natural selection for symmetry. The dependence of results on the choice of appropriate traits for examination is thus one limitation of this technique. Other concerns include the severity of stress required to induce significant increases in FA, the potentially confounding effects of selective mortality, and the capacity of measurement error to obscure or bias results. These factors may reduce the utility of the technique as a tool for environmental assessment or management purposes.

Shauna Murray

Shauna completed an honours degree in 2000 looking at the population ecology of Noctiluca scintillans.

The population ecology of the red tide forming dinoflagellate Noctiluca scintillans was examined in Botany Bay and Port Hacking, NSW, from July 1996 to March 1997. The condition and abundance of Noctiluca changed markedly between months. Bloom conditions (defined by >1000 cells per litre) occured in c, and were characterised by Noctiluca dominating the >100um zooplankton size fraction. Abundances were greater offshore than in the estuary during all months.

Cell size, nutritional status, and the proportion of reproductive stages of Noctiluca from different months were interpreted with reference to previous culturing studies and the senescent red tide populations, as the culture of local populations could not be achieved. Qualitative differences were found to between the two bloom events in September and January/February. Noctiluca in September were smaller (340-450um), actively feeding and dividing, and were associated with high chlorophyll a concentrations. The January/February populations were larger (550-700um), most similar to the senescent red tides, and were associated with low chlorophyll a concentrations.

Reasons for this qualitative difference may relate to the mechanism of bloom formation, with the September bloom showing evidence of in situ growth, and the January/February bloom indicating previous growth, possibly in a distant water body. There was no indication that the abundance or condition of Noctiluca were determined by broad temporal changes to temperature or day length. The growth of Noctiluca therefore appears to be attributable to phytoplankton abundance and is influence more by factors affecting phytoplankton growth then physical factors.

Steven Rutten

Steven completed an Honours in 1998 looking at theuse of carbon and nitrogen stable isotopes in zooplankton for investigating the nutritional siginifcance of upwelling for the Sydney coastal food chain.

Zooplankton collected off Sydney before, during, and after a wind driven upwelling event that occurred during January 1998. Multidimensional scaling analysis (MDS) revealed that upwelling resulted in a reduction in the abundance of all taxa within the coastal zooplankton community. Little evidence was found for the introduction of new taxa, and the coastal community was seen to return to its original state within three weeks after the upwelling. The naked dinoflagellate Noctiluca scintillans dominated zooplankton numbers during early December and late January, yet exhibited a population decline in late December independent of the upwelling.

Carbon and nitrogen stable isotope analysis was performed on zooplankton collected during dates bracketing the upwelling event. This included analyses of total net zooplankton, and of the most abundant crustacean taxon, the cladoceran Penilia schmackeri. No significant differences were found among dates for d15N and d13C of net zooplankton samples. However, during the event a significant increase in 15N and a significant decrease in d13C was noted in P. schmackeri, indicating that P. schmackeri had assimilated upwelled nutrients that were isotopically distinct from nutrients normally present in Sydney's coastal waters.

Laboratory experiments designed to estimate turnover rates of d15N and d13C in zooplankton were performed on Artemia franciscana (brine shrimp) nauplii reared at 15°C and 25°C, and at high and low food concentration. Complete isotopic turnover was expected to occur in A. franciscana nauplii within 3-6 days across all treatment combinations. In the field similarly sized crustaceans such as copepods and cladocerans may also be capable of complete isotopic turnover within days.

The results of this study suggest that stable isotope analysis of crustacean zooplankters off Sydney is a viable technique for tracing the assimilation of upwelled nutrients into the coastal pelagic food chain.

Tanya Compton

Tanya completed her Honours in 2000 tracing nutrient sources in Jervis Bay, NSW.

Temperature, water and zooplankton samples were collected in Jervis Bay, NSW over the summer months of December 1999 to March 2000. Summer months are prone to upwelling favourable winds, therefore making this an ideal period to compare the relative magnitude of upwelling versus sewage effluent into Jervis Bay.

Nutrient samples were measured for nitrates, phosphates, ammonia and silicates and analysed with principal component analysis. Nutrient and temperature data indicated no sewage effect and two dates (8 & 16 February) strongly prone to upwelling. Zooplankton size distributions were measured with a laboratory-based optical plankton counter and analysed with principal component analysis and the analysis of variance.

Size distributions were not significantly different in the vicinity of the sewage outfall. They did however became very different on the upwelling dates. The copepod Temora turbinata was extracted from samples and measured for carbon and nitrogen isotopes. Results from the analysis of variance indicated that the ratios were not related to the isotope ratios obtained from the outfall. Instead the ratios were more significant with the first upwelling event on 8 February as carbon ratios became depleted followed by a depletion of nitrogen on the 16 February.

Future work focussing on the effects of sewage may be more significant with the use of mesocosm experiments or bivalves. This experiment is a good pilot study for the biological oceanography along the New South Wales Coast.