Journal articles: 'Estuaries New Zealand'

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Plew, David R., John R. Zeldis, Bruce D. Dudley, Amy L. Whitehead, Leigh M. Stevens, Barry M. Robertson, and Ben P. Robertson. "Assessing the Eutrophic Susceptibility of New Zealand Estuaries." Estuaries and Coasts 43, no. 8 (April 28, 2020): 2015–33. http://dx.doi.org/10.1007/s12237-020-00729-w.

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Abstract We developed a method to predict the susceptibility of New Zealand estuaries to eutrophication. This method predicts macroalgae and phytoplankton responses to potential nutrient concentrations and flushing times, obtained nationally from simple dilution models, a GIS land-use model and physical estuary properties. Macroalgal response was based on an empirically derived relationship between potential nitrogen concentrations and an established macroalgal index (EQR) and phytoplankton response using an analytical growth model. Intertidal area was used to determine which primary producer was likely to lead to eutrophic conditions within estuaries. We calculated the eutrophication susceptibility of 399 New Zealand estuaries and assigned them to susceptibility bands A (lowest expected impact) to D (highest expected impact). Twenty-seven percent of New Zealand estuaries have high or very high eutrophication susceptibilities (band C or D), mostly (63% of band C and D) due to macroalgae. The physical properties of estuaries strongly influence susceptibility to macroalgae or phytoplankton blooms, and estuaries with similar physical properties cluster spatially around New Zealand’s coasts. As a result, regional patterns in susceptibility are apparent due to a combination of estuary types and land use patterns. The few areas in New Zealand with consistently low estuary eutrophication susceptibilities are either undeveloped or have estuaries with short flushing times, low intertidal area and/or minimal tidal influx. Estuaries with conditions favourable for macroalgae are most at risk. Our approach provides estuary-integrated susceptibility scores likely to be of use as a regional or national screening tool to prioritise more in-depth estuary assessments, to evaluate likely responses to altered nutrient loading regimes and assist in developing management strategies for estuaries.

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Taddese, Fasil, Marc Schallenberg, Pavel Mikheev, Matt G. Jarvis, and Gerard P. Closs. "Ichthyofaunal assemblages in shallow littoral habitats of permanently open estuaries and intermittently closed and open lakes or lagoons in Otago, New Zealand." Marine and Freshwater Research 69, no. 8 (2018): 1222. http://dx.doi.org/10.1071/mf17334.

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Fish assemblages of New Zealand estuaries are poorly studied, and knowledge of the effects of estuary–ocean connections on the ichthyofaunal composition of estuaries remains limited. Understanding the status of fish composition of estuaries is crucial for planning for sustainable management of aquatic ecosystems. In the present study we sampled fish using a seine net from lower reaches of six permanently open estuaries and six intermittently closed and open lakes or lagoons (ICOLLs) along the Otago coastline during winter 2016 and summer 2017. Marked differences in ichthyofaunal composition were observed in the shallow littoral habitats of permanently open estuaries and ICOLLs. Fish assemblages reflected estuary–ocean connection status of estuaries during both seasons. ICOLLs showed greater fish abundance than permanently open systems. Fish abundance was higher in summer than in winter in both estuary types. Fish species with marine–estuarine opportunist and estuarine–migrant life histories dominated permanently open estuaries. Conversely, species with a diadromous life history but known to form landlocked populations were abundant in ICOLLs. Salinity and temperature were correlated with fish abundance in both estuary types.

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Francis, Malcolm P., Mark A. Morrison, John Leathwick, and Cameron Walsh. "Predicting patterns of richness, occurrence and abundance of small fish in New Zealand estuaries." Marine and Freshwater Research 62, no. 11 (2011): 1327. http://dx.doi.org/10.1071/mf11067.

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Estuarine fish habitats are vulnerable to human impacts and are poorly studied. We surveyed 69 of New Zealand’s 443 estuaries across 1500 km to: determine species composition of small fishes; model and predict their richness, occurrence and abundance; test marine classification schemes as a basis for Marine Protected Areas; and inform impact mitigation measures. Boosted regression tree models produced acceptable fits for richness and occurrence at estuary and site scales and abundance at the site scale. Richness was greatest in northern North Island; the best predictors were estuary area and area of intertidal habitat. Within estuaries, richness increased towards the head, as water clarity declined and the substratum became muddier. Air temperature, estuary and intertidal area, tidal range and freshwater and seawater influx were the best predictors of occurrence at the estuary scale; water temperature and salinity were important at the site scale. Biological classification schemes seldom improved model fits and have little predictive utility. Richness predictions were made for 380 estuaries and occurrence predictions for 16 species. These predictions inform resource managers about estuarine fishes within their jurisdiction, bypassing the need to undertake expensive field surveys. However, sampling of environmental predictors is still required to drive some models.

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Lill, Adrian W. T., Aparna Lal, and Gerard P. Closs. "Life history and reproduction of two abundant mysids (Mysidacea: Mysidae) in an intermittently open New Zealand estuary." Marine and Freshwater Research 61, no. 6 (2010): 633. http://dx.doi.org/10.1071/mf09085.

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Mysids typically form a large proportion of the hyperbenthic faunal biomass in estuaries and are central to the functioning of estuarine food webs. The population dynamics, annual life histories and reproductive effort of two common temperate estuarine mysids, Tenagomysis chiltoni and T. novae-zealandiae, are described in the intermittently open Kaikorai Lagoon, New Zealand. Mysids were sampled by night, monthly from September 2003 to September 2004. Both species completed their life cycles in the lagoon. There was an apparent spatial separation of breeding populations, with T. chiltoni prevalent in the upper lagoon and T. novae-zealandiae dominating the lower lagoon. Densities were lowest in late winter and peaked in late summer/early autumn for both species. Both species exhibited multivoltine life cycles, with breeding peaks occurring in October 2003, December 2003 and February/March 2004 for T. novae-zealandiae, and October/November 2003 and February/March 2004 for T. chiltoni. Breeding strategy for both species varied over the year with the adult size, brood size and the reproductive effort of both T. novae-zealandiae and T. chiltoni all being highest in spring. The life histories of both T. novae-zealandiae and T. chiltoni in the Kaikorai Lagoon are comparable to life histories described for other temperate estuarine mysid species in large open estuaries, and were not significantly modified to cope with the unpredictable demands of life in an intermittent estuary.

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Turner, S. J. "Growth and productivity of intertidalZostera capricorniin New Zealand estuaries." New Zealand Journal of Marine and Freshwater Research 41, no. 1 (March 2007): 77–90. http://dx.doi.org/10.1080/00288330709509897.

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Vant, W. N. "Causes of light attenuation in nine New Zealand estuaries." Estuarine, Coastal and Shelf Science 31, no. 2 (August 1990): 125–37. http://dx.doi.org/10.1016/0272-7714(90)90042-p.

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Hesp, P. A., M. J. Shepherd, and K. Parnell. "Coastal geomorphology in New Zealand, 1989-99." Progress in Physical Geography: Earth and Environment 23, no. 4 (December 1999): 501–24. http://dx.doi.org/10.1177/030913339902300403.

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This article reviews coastal geomorphological research published in New Zealand or international journals which has been carried out in New Zealand during the past ten years. All coastal environments are covered, including tidal inlets, estuaries and lagoons, beach, surfzone, nearshore and shelf environments, and rocky coasts. Applied coastal studies are also covered. While the New Zealand coastal science community remains relatively small, a significant body of work has been carried out, much of it innovative and unique. However, with 11 000 km of very diverse coastline covering 13 degrees of latitude available for study, there are many areas, geographical as well as disciplinary, that remain poorly researched.

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Lill, Adrian W. T., Gerard P. Closs, Candida Savage, and Marc Schallenberg. "Annual secondary production of two estuarine mysid species (Mysidacea: Mysidae) inhabiting an intermittently closed estuary, south-eastern New Zealand." Marine and Freshwater Research 62, no. 7 (2011): 823. http://dx.doi.org/10.1071/mf10274.

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Estimates of secondary production are essential to understanding how communities function. Estimates of secondary production for key species such as mysids are scarce, especially in estuarine environments. There are no estimates for mysid production in intermittently closed estuaries in the world, and no estimates for endemic New Zealand mysids. The current study presents length–mass models for two mysid species (Tenagomysis chiltoni Tattersall, 1923 and T. novae-zealandiae Thomson, 1900) from the south-eastern coast of the South Island, New Zealand. Kaikorai Lagoon, a small intermittently closed estuary, supported a large average annual biomass of T. novae-zealandiae (861.77 mg m–2) and T. chiltoni (971.90 mg m–2). The Hynes average-cohort method was used with length–mass models to estimate the annual production of breeding populations of T. chiltoni and T. novae-zealandiae collected over a year in parts of the Kaikorai Lagoon. Compared with similar temperate ecosystems worldwide, the studied ecosystem indicated high annual production (11 328.8 mg m–2 year–1 and 6585.2 mg m–2 year–1) and turnover rates (P : B) (13.16 and 6.78) for T. novae-zealandiae and T. chiltoni, respectively. High annual secondary production may be due to relatively stable hydrological and food conditions found in intermittently closed estuaries, leading to dense stable populations that are maintained through much of the year.

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Heggie, Keira, and Candida Savage. "Nitrogen yields from New Zealand coastal catchments to receiving estuaries." New Zealand Journal of Marine and Freshwater Research 43, no. 5 (December 2009): 1039–52. http://dx.doi.org/10.1080/00288330.2009.9626527.

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10

Lill, Adrian W. T., Gerard P. Closs, Candida Savage, and Marc Schallenberg. "Corrigendum to: Annual secondary production of two estuarine mysid species (Mysidacea : Mysidae) inhabiting an intermittently closed estuary, south-eastern New Zealand." Marine and Freshwater Research 63, no. 4 (2012): 385. http://dx.doi.org/10.1071/mf10274_co.

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Estimates of secondary production are essential to understanding how communities function. Estimates of secondary production for key species such as mysids are scarce, especially in estuarine environments. There are no estimates for mysid production in intermittently closed estuaries in the world, and no estimates for endemic New Zealand mysids. The current study presents length?mass models for two mysid species (Tenagomysis chiltoni Tattersall, 1923 and T. novae-zealandiae Thomson, 1900) from the south-eastern coast of the South Island, New Zealand. Kaikorai Lagoon, a small intermittently closed estuary, supported a large average annual biomass of T. novae-zealandiae (861.77 mg m?2) and T. chiltoni (971.90 mg m?2). The Hynes average-cohort method was used with length?mass models to estimate the annual production of breeding populations of T. chiltoni and T. novae-zealandiae collected over a year in parts of the Kaikorai Lagoon. Compared with similar temperate ecosystems worldwide, the studied ecosystem indicated high annual production (11 328.8 mg m?2 year?1 and 6585.2 mg m?2 year?1) and turnover rates (P : B) (13.16 and 6.78) for T. novae-zealandiae and T. chiltoni, respectively. High annual secondary production may be due to relatively stable hydrological and food conditions found in intermittently closed estuaries, leading to dense stable populations that are maintained through much of the year.

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Paul, Sourav, Martin Krkosek, P. Keith Probert, and Gerard P. Closs. "Osmoregulation and survival of two mysid species of Tenagomysis in southern estuaries of New Zealand." Marine and Freshwater Research 64, no. 4 (2013): 340. http://dx.doi.org/10.1071/mf12316.

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The mysid shrimps Tenagomysis chiltoni and T. novaezealandiae are abundant in southern New Zealand estuaries; however, little is known of their osmoregulatory capacity and survival. We investigated their osmoregulation and survival under salinities of 0, 5, 10, 15, 20, 25, 30 and 33 at 5°C and 20°C, to evaluate if the variation in salinity limits their distribution in estuaries. T. chiltoni and T. novaezealandiae maintained species-specific haemolymph concentrations across the salinities tested. According to AIC model selection statistics, for osmoregulatory capacity, the combined effects of salinity and temperature emerged as the most parsimonious. For survival, the non-linear effect of salinity was found as the most supported model given the data. Mortality of T. chiltoni and T. novaezealandiae increased towards the extremes of fresh and salt water but was lower in intermediate salinities (10–25). The ability of these species to osmoregulate and survive were limited at 5°C, but improved at 20°C. Life-history stage was found to be critical for explaining the variations in survival. We concluded that salinity could influence osmoregulation and survival of Tenagomysis spp., and when interacting with temperature and life-history stage, may partly explain why both shrimp species could be found in intermediate salinities and why T. chiltoni is more prevalent in the upper reaches of southern New Zealand estuaries.

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12

Scarsbrook, M. R., and A. R. Melland. "Dairying and water-quality issues in Australia and New Zealand." Animal Production Science 55, no. 7 (2015): 856. http://dx.doi.org/10.1071/an14878.

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The scale and intensity of dairy farming can place pressure on our freshwater resources. These pressures (e.g. excessive soil nutrient concentrations and nitrogen excretion) can lead to changes in the levels of contaminants in waterways, altering the state and potentially affecting the uses and values society ascribes to water. Resource management involves putting in place appropriate responses to address water-quality issues. In the present paper, we highlight trends in the scale and extent of dairying in Australia and New Zealand and describe water-quality pressures, state, impacts and responses that characterise the two countries. In Australia and New Zealand, dairy farming has become increasingly intensive over the past three decades, although the size of Australia’s dairy herd has remained fairly static, while New Zealand’s herd and associated excreted nitrogen loads have nearly doubled. In contrast, effluent management has been improved, and farm waterways fenced, in part to reduce pressure on freshwater. However, both countries show a range of indicators of degraded water-quality state. Phosphorus and nitrogen are the most common water-quality indicators to exceed levels beyond the expected natural range, although New Zealand also has a significant percentage of waterways with faecal contaminants beyond acceptable levels for contact recreation. In New Zealand, nitrate concentrations in waterways have increased, while phosphorus and suspended sediment concentrations have generally decreased over the past decade. Water quality in some coastal estuaries and embayments is of particular concern in Australia, whereas attention in New Zealand is on maintaining quality of high-value lakes, rivers and groundwater resources, as well as rehabilitating waterbodies where key values have been degraded. In both Australia and New Zealand, water-quality data are increasingly being collated and reported but in Australia long-term trends across waterbodies, and spatially comprehensive groundwater-quality data have not yet been reported at national levels. In New Zealand, coastal marine systems, and particularly harbours and estuaries, are poorly monitored, but there are long-term monitoring systems in place for rivers, groundwater and lakes. To minimise pressures on water quality, there is a high reliance on voluntary and incentivised practice change in Australia. In New Zealand, industry-led practice change has been important over the past decade, but regulated environmental limits for dairy farmers are increasing. Dairy industries in both countries have set targets for reducing pressures through sustainability frameworks and accords. To address future drivers such as climate change and increasing domestic and international market demand for sustainability credentials, definitions of values and appropriate targets for waterbodies draining agricultural landscapes will be required. Environmental limits (both natural and societal) will constrain future growth opportunities for dairying and research into continued growth within limits remains a priority in both countries.

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Dencer-Brown, Amrit Melissa, Andrea C. Alfaro, and Simon Milne. "Muddied Waters: Perceptions and Attitudes towards Mangroves and Their Removal in New Zealand." Sustainability 11, no. 9 (May 7, 2019): 2631. http://dx.doi.org/10.3390/su11092631.

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Seaward expansion of New Zealand’s mangrove Avicennia marina (subsp.) australasica in estuaries has led to disparity in opinion over their social-ecological value. This study investigated existing stakeholders and interested parties’ perceptions and attitudes towards mangroves, focusing on four sites in Auckland. A mixed methods design was used consisting of semi-structured interviews, ratings of importance of mangrove ecosystem services and issues and Q-sorts on mangrove social-ecological statements. 29 participants were interviewed in person. Results revealed a disparity in perceptions and attitudes towards mangroves. Community Groups displayed strongly negative opinions towards mangrove preservation and Conservation Organisations expressed a strongly positive stance. The occupation of participants was a significant factor in the ratings. Overall, sediment and nutrient retention were rated as the most important ecosystem services. The desire for reversion of estuaries to a “pre-mangrove” state is the greatest issue affecting mangroves. Q-analysis revealed loading of participants onto two factors representing (1) a pro-preservation attitude towards mangrove and (2) a neutral view. Managing sediment loads and nutrient run-off in the wider catchment were highlighted as ways to reduce mangrove expansion. Improving water quality and the health of the harbour was of utmost priority to kaitiaki (Māori guardians of the environment). This study provides critical insights into the management of mangroves as social-ecological systems.

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Paul, S., DM May, M. Lee, and GP Closs. "Body and brood sizes ofTenagomysisspp. (Crustacea: Mysida) in southern estuaries in New Zealand." New Zealand Journal of Marine and Freshwater Research 50, no. 3 (July 2, 2016): 433–43. http://dx.doi.org/10.1080/00288330.2016.1154077.

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Berthelsen, A., J. Atalah, D. Clark, E. Goodwin, M. Patterson, and J. Sinner. "Relationships between biotic indices, multiple stressors and natural variability in New Zealand estuaries." Ecological Indicators 85 (February 2018): 634–43. http://dx.doi.org/10.1016/j.ecolind.2017.10.060.

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Turner, S. J., and A. M. Schwarz. "Biomass development and photosynthetic potential of intertidal Zostera capricorni in New Zealand estuaries." Aquatic Botany 85, no. 1 (July 2006): 53–64. http://dx.doi.org/10.1016/j.aquabot.2005.12.006.

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Mitchell, Stuart F., and J. Mark R. Edwards. "A new species ofScolecolepides(Polychaeta: Spionidae) from some South Island lakes and estuaries in New Zealand." New Zealand Journal of Zoology 15, no. 3 (July 1988): 391–95. http://dx.doi.org/10.1080/03014223.1988.10422965.

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Tay, Hui W., Karin R. Bryan, Conrad A. Pilditch, Stephen Park, and David P. Hamilton. "Variations in nutrient concentrations at different time scales in two shallow tidally dominated estuaries." Marine and Freshwater Research 63, no. 2 (2012): 95. http://dx.doi.org/10.1071/mf11102.

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Water-quality observations in estuaries can be highly variable in time and space, making it difficult to quantify nutrient fluxes and to discriminate patterns. We measured nitrate, phosphate and ammonium concentrations in two shallow tidally dominated estuaries in Tauranga Harbour, New Zealand, during four periods (winter, start of spring, end of spring and summer) within 1 year, to determine the source of variability observed in a 19-year monitoring program. These measurements consisted of high-frequency monitoring during one 24-h period (covering a daytime flood-ebb tide and a night-time flood-ebb tide) at each estuary. Concentrations of nitrate and ammonium had distinctive tidal patterns, with rising values during ebb flows. This tidal asymmetry caused a net seaward flux of dissolved inorganic nitrogen (nitrate and ammonium), with higher exports at night. Net fluxes were 34–358 kg N per tidal cycle for nitrate and 22–93 kg N per tidal cycle for ammonium. Fluxes were large relative to previously published model-based predictions for the region, particularly during winter. Our results showed that estuarine sampling strategies need to account for tidal variability and the role of episodic runoff events, and highlighted the importance of correctly validated mass fluxes from field measurements for comparisons with nutrient-loading models.

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Gladstone-Gallagher, Rebecca V., Dean R. Sandwell, Andrew M. Lohrer, Carolyn J. Lundquist, and Conrad A. Pilditch. "Quantifying macrodetritus fluxes from a small temperate estuary." Marine and Freshwater Research 68, no. 12 (2017): 2289. http://dx.doi.org/10.1071/mf16408.

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Empirical measurements of estuary-to-coast material fluxes usually exclude the fraction of primary production that is exported as macrodetritus (marine plant litter), potentially leaving a gap in our understanding of the role of estuaries as outwelling systems. To address this gap, we sampled water and suspended material seasonally from the mouth of Pepe Inlet, Tairua Estuary, New Zealand. From samples collected hourly over 24h, we calculated the lateral tidal fluxes (import, export, net flux) of macrodetritus, particulate and dissolved forms of nitrogen (N) and phosphorus (P). Annually, the inlet was a net exporter of N and P (5145 and 362kg respectively). However, macrodetritus accounted for <13 and <3% of seasonal N and P exports respectively. Macrodetritus is an obvious and visible source of estuary-to-coast subsidy, but our derived nutrient budgets suggest the dissolved and particulate forms dominate the net export of N and P (>87%). Nevertheless, seasonal pulses in the source and supply of macrodetritus may have consequences for the temporal scales over which this resource subsidy affects receiving ecosystems (e.g. intertidal sandflats). These mensurative investigations are useful to inform estuarine nutrient budgets that quantify the ecosystem services provided by temperate estuaries (e.g. contribution to fisheries food webs).

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Gall, Mark, Andrew Swales, Rob Davies-Colley, and David Bremner. "Predicting visual clarity and light penetration from water quality measures in New Zealand estuaries." Estuarine, Coastal and Shelf Science 219 (April 2019): 429–43. http://dx.doi.org/10.1016/j.ecss.2019.01.003.

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Taddese, Fasil, and Gerard P. Closs. "Spatiotemporal ichthyofaunal dynamics in a permanently open estuary, Otago, New Zealand." Marine and Freshwater Research 71, no. 1 (2020): 107. http://dx.doi.org/10.1071/mf19034.

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Understanding the spatial and temporal dynamics of the fish-assemblage structure of estuaries is indispensable in conservation and habitat-improvement efforts. This study reports seasonal as well as spatial dynamics of fish diversity of the Waikouaiti Estuary and indicates the key physicochemical variables that influence the ichthyofauna of the estuary. Fish were collected from upper, middle and lower reaches of the Waikouaiti Estuary monthly for 1 year, by using a seine net. In total, 15 species and 4967 individuals were collected during the study period. Distinct differences in ichthyofaunal composition, driven by spatiotemporal environmental heterogeneity, were observed between the three reaches of the Waikouaiti Estuary. Fish abundance was higher in the middle reach where the water is turbid. Whereas fish species with diadromous life history occurred more frequently in the upper reach of the estuary, marine-migrants and marine-stragglers were abundant in the lower reach. The present study indicated that salinity and turbidity were the best predictors of fish species composition in the different reaches of the Waikouaiti Estuary.

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Bellais, Kaylyn C., Samuel T. Barber, Donald A. Beebe, and Murlene W. Clark. "Lake or Estuary? Sedimentary and Benthic Foraminiferal Characterization of a Gulf of Mexico Coastal Dune Lake." Gulf and Caribbean Research 31 (2020): SC46—SC52. http://dx.doi.org/10.18785/gcr.3101.18.

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Coastal dune lakes are shallow estuaries located within dune environments that share a permanent or intermittent connection with the sea. Because coastal dune lakes are found in few locations worldwide (e.g. Australia, New Zealand, Florida, etc.) they represent unique environments worthy of protection. However; there is a distinct lack of scientific data related to the function and ecology of coastal dune lakes, especially in the Gulf of Mexico. Therefore, the purpose of this study was to characterize the sedimentology and foraminifera of a representative coastal dune lake in Walton County, FL (i.e. Eastern Lake) and determine whether it shares geologic similarities with nearby estuaries. Ten Ekman sediment grab samples were collected along a transect spanning the length of Eastern Lake. The samples were processed to determine sedimentary properties and foraminiferal assemblages. Results from the sedimentary and foraminiferal analyses reveal 3 distinct depositional environments including: (1) a coarse grained, moderately well sorted, organic poor, sandy beach facies with both agglutinated and calcareous foraminifera, (2) a fine grained, very poorly sorted, organic rich central mud basin facies with mostly calcareous foraminifera, and (3) a coarse grained, poorly sorted, organic rich sandy marsh delta facies dominated by agglutinated foraminifera. These environments and foraminiferal patterns are also found in much larger nearby estuaries including Choctawhatchee Bay, Pensacola Bay, and Mobile Bay. Our results therefore suggest that coastal dune lakes may serve as down-scaled micro-estuaries and are functionally related to larger estuaries of the Gulf Coast despite their size.

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Gongol, C., and C. Savage. "Spatial variation in rates of benthic denitrification and environmental controls in four New Zealand estuaries." Marine Ecology Progress Series 556 (September 8, 2016): 59–77. http://dx.doi.org/10.3354/meps11865.

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MacKenzie, Lincoln A., Andrew I. Selwood, Paul McNabb, and Lesley Rhodes. "Benthic dinoflagellate toxins in two warm-temperate estuaries: Rangaunu and Parengarenga Harbours, Northland, New Zealand." Harmful Algae 10, no. 6 (September 2011): 559–66. http://dx.doi.org/10.1016/j.hal.2011.02.007.

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Hume, Terry M., and Jeremy G. Gibb. "The “Wooden-Floor” marker bed—A new method of determining historical sedimentation rates in some New Zealand estuaries." Journal of the Royal Society of New Zealand 17, no. 1 (March 1987): 1–7. http://dx.doi.org/10.1080/03036758.1987.10421703.

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Mangan, S., KR Bryan, SF Thrush, RV Gladstone-Gallagher, AM Lohrer, and CA Pilditch. "Shady business: the darkening of estuaries constrains benthic ecosystem function." Marine Ecology Progress Series 647 (August 13, 2020): 33–48. http://dx.doi.org/10.3354/meps13410.

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Coastal intertidal soft-sediment habitats provide ecosystem services to millions of people worldwide, yet are under intense pressure from land-use change and sea-level rise (SLR). Both pressures interact to reduce light reaching the seafloor, thereby disrupting benthic primary producers and the ecosystem functions and services they provide. This study considers the implications of altered light climate on microphytobenthic (MPB) production in shallow estuaries. Continuous measurements of seafloor photosynthetically active radiation (PAR) were made over 9 mo on intertidal sandflats in 14 New Zealand estuaries spanning a turbidity gradient. A literature summary of benthic photosynthesis-irradiance curves was used to predict PAR limitation at sampling sites. Estimates of the proportion of time MPB would be light limited during emersion ranged from a median of 32-64% compared to a median of 55-100% during immersion. For estuaries close to 100% PAR limitation during immersion, emerged intertidal areas represent a refuge for MPB production which is vulnerable to SLR. Based on hypsometric curves (a representation of estuary bathymetry), the intertidal area of our study estuaries is predicted to decrease by 27-94% in response to SLR of 1.4 m. The combination of high PAR limitation during immersion and large losses of intertidal area will increase vulnerability to the loss of MPB production and the associated ecosystem services, which will push these ecosystems towards tipping points. The research highlights how the interplay between local and global scale stressors may ultimately trigger ecological collapse under future global change.

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Hume, Terry M., and Charles E. Herdendorf. "A geomorphic classification of estuaries and its application to coastal resource management—A New Zealand example." Ocean and Shoreline Management 11, no. 3 (January 1988): 249–74. http://dx.doi.org/10.1016/0951-8312(88)90022-7.

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Schüller, Susanne E., Thomas S. Bianchi, Xinxin Li, Mead A. Allison, and Candida Savage. "Historical Reconstruction of Phytoplankton Composition in Estuaries of Fiordland, New Zealand: the Application of Plant Pigment Biomarkers." Estuaries and Coasts 38, no. 1 (February 1, 2014): 56–71. http://dx.doi.org/10.1007/s12237-014-9771-z.

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van Houte-Howes, K. S. S., S. J. Turner, and C. A. Pilditch. "Spatial differences in macroinvertebrate communities in intertidal seagrass habitats and unvegetated sediment in three New Zealand estuaries." Estuaries 27, no. 6 (December 2004): 945–57. http://dx.doi.org/10.1007/bf02803421.

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O’Connell-Milne, SA, SR Wing, SH Suanda, JA Udy, LM Durante, NH Salmond, and LC Wing. "Interactions between bivalve filter feeding and oceanographic forcing drive the fluxes of organic matter and nutrients at an estuarine-coastal interface." Marine Ecology Progress Series 655 (November 26, 2020): 29–42. http://dx.doi.org/10.3354/meps13522.

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Fluxes of nutrients and organic matter between estuaries and the open coast comprise an important component of ecosystem connectivity. Nevertheless, relatively little is known about how oceanographic processes, for example onshore retention of water in the coastal boundary layer, interact with major sinks for particulate organic matter such as bivalve filter feeding within inlets and estuaries. To investigate this interaction, total fluxes of water, nutrients (NH4, NOx and PO4) and chlorophyll a between Waitati Inlet on the wave-exposed coast of the South Island, New Zealand, and the coastal ocean were quantified over 40 tidal cycles. We found declines in total flux of phytoplankton and increases in flux of NH4 between flood and ebb tides. Net declines in phytoplankton biomass followed a Type II functional response curve, consistent with consumption by the large biomass of filter feeding bivalves within the inlet; however, an asymptote was not reached for the highest concentrations, indicating that feeding was likely limited by exposure time rather than concentration of food relative to biomass. An information-theoretic framework was then used to infer the most likely combination of environmental conditions influencing total fluxes of phytoplankton into the inlet. Onshore wind stress, wave transport and salinity explained 90% of the variation in flux of phytoplankton entering the inlet on flood tides. These results highlight the importance of the interaction between oceanographic forcing and bivalve filter feeding in modulating material dynamics and connectivity between estuaries and the coastal ocean.

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Weeks, Emily S., Russell G. Death, Kyleisha Foote, Rosalynn Anderson-Lederer, Michael K. Joy, and Paul Boyce. "Conservation Science Statement. The demise of New Zealand's freshwater flora and fauna: a forgotten treasure." Pacific Conservation Biology 22, no. 2 (2016): 110. http://dx.doi.org/10.1071/pc15038.

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New Zealand’s freshwater ecosystems support a diverse and unique array of endemic flora and fauna. However, the conservation of its freshwater biodiversity is often overlooked in comparison to terrestrial and marine environments, and is under increasing threat from agricultural intensification, urbanisation, climate change, invasive species, and water abstraction. New Zealand has some of the highest levels of threatened freshwater species in the world with, for example, up to 74% of native freshwater fish listed as endangered or at risk. Threatened species are often discounted in water policy and management that is predominantly focussed on balancing water quality and economic development rather than biodiversity. We identify six clear actions to redress the balance of protecting New Zealand’s freshwater biodiversity: 1. change legislation to adequately protect native and endemic fish species and invertebrates, including those harvested commercially and recreationally; 2. protect habitat critical to the survival of New Zealand’s rare and range-restricted fish, invertebrate and plant freshwater species; 3. include river habitat to protect ecosystem health in the National Objectives Framework for the National Policy Statement for freshwater; 4. establish monitoring and recovery plans for New Zealand’s threatened freshwater invertebrate fauna; 5. develop policy and best management practices for freshwater catchments in addition to lakes and rivers to also include wetlands, estuaries, and groundwater ecosystems; and 6. establish, improve, and maintain appropriately wide riparian zones that connect across entire water catchments. We have published these recommendations as a scientific statement prepared for the Oceania Section of the Society for Conservation Biology to facilitate communication of our thoughts to as wide an audience as possible (https://conbio.org/images/content_groups/Oceania/Scientific_Statement_1_.pdf, accessed 8 February 2016).

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Mangan, Stephanie, Andrew M. Lohrer, Simon F. Thrush, and Conrad A. Pilditch. "Water Column Turbidity Not Sediment Nutrient Enrichment Moderates Microphytobenthic Primary Production." Journal of Marine Science and Engineering 8, no. 10 (September 23, 2020): 732. http://dx.doi.org/10.3390/jmse8100732.

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Soft sediment intertidal habitats are under intense anthropogenic pressure resulting from increased land derived sediment and nutrient delivery. Long term, this can cause high water column turbidity and nutrient enrichment of sediment porewaters, which has cascading effects on coastal ecosystem functionality. However, how these stressors may interact and influence benthic productivity over alternating periods of submergence and emergence is largely unknown. This study investigates the effects of sediment nutrient enrichment (at three levels for 20 months) on benthic primary production at six sites in four New Zealand estuaries that spanned a gradient in water column turbidity. While nutrient enrichment had no detectable effect on microphytobenthic primary production, water column turbidity had a significant influence, explaining up to 40% of variability during tidal submergence, followed by temperature and sediment characteristics. In addition, negative net primary production (NPP) estimates and therefore net heterotrophy for the most turbid estuaries during tidal submergence resulted in an increased reliance on production during emerged periods, where NPP was positive across all sites. This study highlights the prominent role of water column turbidity over nutrient enrichment in moderating microphytobenthic production, and the increasing importance of emerged periods to maintain the health and functioning of coastal habitats.

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Curtis, Thomas D., and Jeffrey S. Shima. "Geographic and sex‐specific variation in growth of yellow‐eyed mullet,Aldrichetta forsteri,from estuaries around New Zealand." New Zealand Journal of Marine and Freshwater Research 39, no. 6 (December 2005): 1277–85. http://dx.doi.org/10.1080/00288330.2005.9517392.

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Lovelock, Catherine E., Ilka C. Feller, Joanne Ellis, Ann Maree Schwarz, Nicole Hancock, Pip Nichols, and Brian Sorrell. "Mangrove growth in New Zealand estuaries: the role of nutrient enrichment at sites with contrasting rates of sedimentation." Oecologia 153, no. 3 (May 10, 2007): 633–41. http://dx.doi.org/10.1007/s00442-007-0750-y.

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Kennedy, David M., Beth V. Risdon, and Josephine LD Woods. "Holocene sea-level change and estuary infill in North West Nelson, central New Zealand." Holocene 32, no. 3 (November 21, 2021): 113–26. http://dx.doi.org/10.1177/09596836211060489.

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The sedimentary sequences found within estuaries in the north west Nelson region of central New Zealand are investigated in order to quantify the timing of the end of the Post Glacial Marine Transgression. This region has been identified as being relatively stable in terms of vertical tectonic movement during the Holocene, but is yet to yield any reconstructions of eustatic sea level. In this study, we investigate the Holocene infill of a barrier estuary (Parapara Inlet) through sedimentological analysis and radiocarbon dating of 18 vibracores up to 4.2 m in length. It is found that the estuary infilled through a combination of lateral flood tide and fluvial delta progradation as well as vertical central basin infill. The central basin infilled at a consistent rate of 0.4 mm/year in both the mid (7.0–6.0 ka) and late-Holocene (2.5–1.5 ka). By the time of early human (Maori) settlement (c. 1 ka), the estuary surface was at low intertidal elevations with sediment being transported from the fluvial to tidal delta. A discernible change in sedimentation rates could not be associated with Maori settlement; however, infill rates increased to at least 12.5 mm/year in the past 150 years due hydraulic sluicing associated with mining. The sedimentary history of Parapara Inlet is compared to nearby Whanganui Inlet, d’Urville Island and Nelson to establish the character of regional Holocene sea level movement. It is found that relative sea level reached modern elevations between 8 and 7 ka in the region. The similarity between sea level curves for the end of the post glacial marine transgression (PMT) to other tectonically stable sites in northern New Zealand suggests that this curve can now be considered a true eustatic signal for the New Zealand archipelago.

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LAST, PETER R., and DANIEL C. GLEDHILL. "The Maugean Skate, Zearaja maugeana sp. nov. (Rajiformes: Rajidae) — a micro-endemic, Gondwanan relict from Tasmanian estuaries." Zootaxa 1494, no. 1 (May 31, 2007): 45–65. http://dx.doi.org/10.11646/zootaxa.1494.1.2.

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A new species of rajin skate, Zearaja maugeana sp. nov., is described on the basis of specimens from two estuaries in remote southwestern Tasmania. The species, known locally as the Maugean Skate, has been assessed as Endangered in the IUCN Red List of Threatened Animals based on its rarity and very narrow geographic range. It is also one of the few skates worldwide to occur mainly in brackish water. The Maugean Skate belongs to a group of anatomically conservative, Dipturus-like skates conforming to the currently unrecognized genus Zearaja Whitley. This ancient group, with a Gondwanan lineage possibly dating back to the Cretaceous, contains at least two other species: Z. nasuta from New Zealand and Z. chilensis from South America. The skeletal morphologies of the Zearaja species are compared with typical Dipturus skates and their phylogenetic position discussed.

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Unwin, M. J., and G. J. Glova. "Changes in life history parameters in a naturally spawning population of chinook salmon (Oncorhynchus tshawytscha) associated with releases of hatchery-reared fish." Canadian Journal of Fisheries and Aquatic Sciences 54, no. 6 (June 1, 1997): 1235–45. http://dx.doi.org/10.1139/f97-031.

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Chinook salmon (Oncorhynchus tshawytscha) spawning runs in Glenariffe Stream, New Zealand, exhibited significant changes in life history traits following supplementation releases of hatchery-reared juveniles. Total run strength did not change but the proportion of naturally produced fish declined to 34%. Attempts to separate spawners of natural and hatchery origin were unsuccessful, and 31-48% of natural spawners are now of hatchery origin. Hatchery males were smaller at age 2 and 3 than males of natural origin, and more often matured as jacks, producing an 86-mm decrease in mean fork length over 28 years. There was no change in length at age or age at maturity for female spawners. The proportion of jacks entering Glenariffe Stream each year was positively correlated with the proportion of jacks in the ensuing cohort. Most differences between fish of natural and hatchery origin were related to hatchery rearing practices, but the decline in age at maturity among naturally produced males appears to reflect traits inherited from parent stock of hatchery origin. Hatchery releases may also favour the survival of ocean-type fry over stream-type fry, possibly reversing a tendency for stream-type behaviour to evolve in response to the lack of estuaries on most New Zealand chinook salmon rivers.

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Cussioli, Mariana Coppede, Dorothea Seeger, Daniel R. Pratt, Karin R. Bryan, Kai Bischof, Willem P. de Lange, Janet F. Bornman, and Conrad A. Pilditch. "Spectral differences in the underwater light regime caused by sediment types in New Zealand estuaries: implications for seagrass photosynthesis." Geo-Marine Letters 40, no. 2 (February 11, 2020): 217–25. http://dx.doi.org/10.1007/s00367-020-00640-0.

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Robertson, Ben P., Jonathan P. A. Gardner, and Candida Savage. "Macrobenthic–mud relations strengthen the foundation for benthic index development: A case study from shallow, temperate New Zealand estuaries." Ecological Indicators 58 (November 2015): 161–74. http://dx.doi.org/10.1016/j.ecolind.2015.05.039.

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Heinrich, Patrick, Lara L. Petschick, Grant L. Northcott, Louis A. Tremblay, James M. Ataria, and Thomas Braunbeck. "Assessment of cytotoxicity, genotoxicity and 7-ethoxyresorufin-O-deethylase (EROD) induction in sediment extracts from New Zealand urban estuaries." Ecotoxicology 26, no. 2 (January 12, 2017): 211–26. http://dx.doi.org/10.1007/s10646-016-1756-1.

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Harris, Rachel J., Conrad A. Pilditch, Barry L. Greenfield, Vicki Moon, and Ingrid Kröncke. "The Influence of Benthic Macrofauna on the Erodibility of Intertidal Sediments with Varying mud Content in Three New Zealand Estuaries." Estuaries and Coasts 39, no. 3 (November 9, 2015): 815–28. http://dx.doi.org/10.1007/s12237-015-0036-2.

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Hayward, Bruce W., George H. Scott, Hugh R. Grenfell, Rowan Carter, and Jere H. Lipps. "Techniques for estimation of tidal elevation and con” nement (∼salinity) histories of sheltered harbours and estuaries using benthic foraminifera: examples from New Zealand." Holocene 14, no. 2 (February 2004): 218–32. http://dx.doi.org/10.1191/0959683604hl678rp.

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Barr, Neill, John Zeldis, Kristin Scheuer, and David Schiel. "Macroalgal Bioindicators of Recovery from Eutrophication in a Tidal Lagoon Following Wastewater Diversion and Earthquake Disturbance." Estuaries and Coasts 43, no. 2 (December 20, 2019): 240–55. http://dx.doi.org/10.1007/s12237-019-00654-7.

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AbstractTogether, macroalgal tissue biochemical nitrogen indices (N-indices) and macroalgal abundance can be used as bioindicators of N-enrichment in estuaries. In this study, we examine the extent and rates of response of Ulva bioindicators during rapid N-enrichment perturbations in the eutrophic Avon-Heathcote Estuary (AHE) (Christchurch, New Zealand). With the diversion of the city’s wastewater discharge away from the estuary in March 2010, a ~ 90% reduction in the estuary’s N-concentration was expected. In turn, this was expected to reduce macroalgal biomass and improve the overall trophic condition of the estuary. We surveyed Ulva bioindicators over a five-year period spanning the diversion. There was a rapid (within one year) transition away from eutrophic condition reflected in N-indices (tissue-chlorophyll, -free amino acids, -N and -δ15N) following wastewater diversion, towards values corresponding with ‘cleaner’ water quality. This was accompanied by large reductions in Ulva percent cover, based on seasonal surveys conducted from 2001 to 2014. However, two large earthquakes in February and June 2011 caused a breakdown of the city’s wastewater infrastructure, resulting in overflows of untreated sewage into the estuary between February and November 2011. The re-enrichment of N and changes in N-sources (treated versus untreated sewage) were rapidly reflected in Ulva bioindicators, notably δ15N. Following repair of infrastructure, Ulva bioindicators again reverted towards a less eutrophic state. Overall, bioindicators were sensitive to changes in N-availability and N-source, and useful for identifying the position of algal populations on a eutrophic-to-oligotrophic gradient. These attributes demonstrated their utility as adjuncts to water quality monitoring and algal biomass surveys.

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Sim-Smith, Carina J., Andrew G. Jeffs, and Craig A. Radford. "Environmental influences on the larval recruitment dynamics of snapper, Chrysophrys auratus (Sparidae)." Marine and Freshwater Research 64, no. 8 (2013): 726. http://dx.doi.org/10.1071/mf12255.

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Recruitment success in demersal fish species that settle in estuaries after a pelagic larval duration in coastal waters is dependent on (1) abiotic and biotic variables that promote good survival, and (2) local environmental conditions that facilitate and direct the transport of larvae to settlement habitats. In the present study, we described the patterns of larval abundance, pelagic larval duration and settlement of a commercially important sparid, Chrysophrys auratus, in northern New Zealand over 2 years, and investigated the relationships among pelagic larval duration or daily settler abundance and various environmental variables. Pelagic larval duration varied from 17 to 33 days and the successful spawning period that produced settled juveniles varied from 29 to 109 days among our four sites. For 91% of fish captured, the average temperature during the pelagic larval duration was >18°C. Significant correlations between daily settler abundance and environmental variables varied among sites and between years; however, temperature, tidal range and on-shore winds were most strongly correlated with settlement, explaining up to 38% of the variability in settler abundance. The present results suggested that, in some locations, high water temperatures, large tides and on-shore winds are likely to increase recruitment success in C. auratus.

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Francis, Malcolm P., David Harasti, and Hamish A. Malcolm. "Surviving under pressure and protection: a review of the biology, ecology and population status of the highly vulnerable grouper Epinephelus daemelii." Marine and Freshwater Research 67, no. 8 (2016): 1215. http://dx.doi.org/10.1071/mf15099.

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Epinephelus daemelii is a threatened serranid grouper species that is restricted to the south-western Pacific Ocean, ranging from eastern Australia to northern New Zealand and the Kermadec Islands. Declines in its abundance due to fishing pressure were reported as early as 1916. Aspects of this species’ biology and behaviour that make it vulnerable include its longevity, late age at maturity, protogynous hermaphroditism, territoriality and limited shallow reef habitat. Adults prefer complex habitat with caves and overhangs at depths of less than 50m, whereas juveniles live in rock pools, shallow intertidal reefs and estuaries. Epinephelus daemelii lives at least 65 years and reaches 170-cm total length. Individuals change sex from female to male at ~100–110cm and ~25 years. Absence of large (>100cm) fish across a large part of their range has implications for reproduction. Although nearly fully protected, incidental bycatch still occurs. A lack of long-term data hinders determination of population status, but abundance appears to be much lower than before, except in remote regions (Kermadec Islands, Elizabeth and Middleton reefs) with extensive no-fishing areas. Further prohibitions on fishing in key locations are likely to be important for the recovery and long-term survival of this species.

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Siciliano, Alfonso, David R. Schiel, and Mads S. Thomsen. "Effects of local anthropogenic stressors on a habitat cascade in an estuarine seagrass system." Marine and Freshwater Research 70, no. 8 (2019): 1129. http://dx.doi.org/10.1071/mf18414.

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Recent research has shown that co-occurring primary and secondary habitat-forming species typically support higher biodiversity than do monocultures of the primary habitat-former alone. However, these ‘habitat cascades’ may not be universal and it is important to know whether, when and where positive effects on biodiversity from secondary habitat-forming species change to negative effects. Here, we tested how anthropogenic stressors (fertilisation and sedimentation) and unattached secondary habitat-forming Ulva seaweeds affected the primary habitat-forming seagrass, Zostera muelleri, and its associated invertebrates in the Avon–Heathcote Estuary, New Zealand. We experimentally stressed Zostera by adding different fertilisation and sediment levels. Fertilisation had little impact, whereas even low sedimentation levels had strong negative effects on Zostera and its associated fauna. In a second experiment, sediments and Ulva were added to seagrass beds and unvegetated mudflats to test whether sediment stress modifies habitat cascades. We found again strong negative effects of sediments on Zostera, irrespective of spatio-temporal conditions, and that negative effects of sediments on invertebrates were enhanced in the presence of the secondary habitat former. These results highlighted that anthropogenic stressors can destabilise habitat cascades; processes that may be of particular importance in estuaries that are characterised by low biodiversity and stressful environmental conditions.

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Byun, Do-Seong, and Deirdre E. Hart. "A monthly tidal envelope classification for semidiurnal regimes in terms of the relative proportions of the S2, N2, and M2 constituents." Ocean Science 16, no. 4 (August 18, 2020): 965–77. http://dx.doi.org/10.5194/os-16-965-2020.

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Abstract. Daily tidal water level variations are a key control on shore ecology, on access to marine environments via ports, jetties, and wharves, on drainage links between the ocean and coastal hydrosystems such as lagoons and estuaries, and on the duration and frequency of opportunities to access the intertidal zone for recreation and food harvesting purposes. Further, high perigean spring tides interact with extreme weather events to produce significant coastal inundations in low-lying coastal settlements such as on deltas. Thus an understanding of daily through monthly tidal envelope characteristics is fundamental for resilient coastal management and development practices. For decades, scientists have described and compared daily tidal forms around the world's coasts based on the four main tidal amplitudes. Our paper builds on this “daily” method by adjusting the constituent analysis to distinguish between the different monthly types of tidal envelopes occurring in the semidiurnal coastal waters around New Zealand. Analyses of tidal records from 27 stations are used alongside data from the FES2014 tide model in order to find the key characteristics and constituent ratios of tides that can be used to classify monthly tidal envelopes. The resulting monthly tidal envelope classification approach described (E) is simple, complementary to the successful and much used daily tidal form factor (F), and of use for coastal flooding and maritime operation management and planning applications in areas with semidiurnal regimes.

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Duncan, Ronlyn. "The Challenges of Regulating Diffuse Agricultural Pollution to Improve Water Quality." Case Studies in the Environment 1, no. 1 (2017): 1–7. http://dx.doi.org/10.1525/cse.2017.sc.433549.

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Worldwide, the cumulative effects of diffuse pollution arising from a range of human activities are diminishing the quality and ecosystem capacity of lakes, rivers, estuaries, and oceans. Devising effective ways to regulate the causes and effects of diffuse pollution is a fraught legal, political, policy, and management challenge given the difficulties in identifying and measuring who is responsible for what, where, and when. In 2011, under its Resource Management Act, 1991, the South Pacific nation of New Zealand introduced national policy to arrest diffuse pollution with a requirement for local government to institute enforceable water quality and quantity limits on all freshwater bodies. The blueprint for these national freshwater policy reforms comes from its South Island region of Canterbury. Canterbury's regional council has adopted a catchment load approach whereby an overarching limit on nutrient losses from agricultural land is calculated and linked to land use rules to control property-scale agricultural activities. With a focus on the Canterbury region, this case study examines two approaches to establishing a catchment load for diffuse nutrient pollution to link to legal provisions in its regional plan. One is based on a river's nutrient concentrations and the other relies on predictive modelling. The case study opens important questions about measuring and regulating diffuse pollution and the difficulties faced by policy-makers and regulators in linking numbers to legally binding compliance and enforcement mechanisms, e.g. how to account for lag effects when establishing ‘in-stream’ limits and how to address changes in software when relying on ‘modelled’ limits?

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CULLEN, DAVID J., G. A. CHALLIS, and G. W. DRUMMOND. "Late Holocene estuarine phosphogenesis in Raglan Harbour, New Zealand." Sedimentology 37, no. 5 (October 1990): 847–57. http://dx.doi.org/10.1111/j.1365-3091.1990.tb01829.x.

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Higham, T. F. G., and A. G. Hogg. "Evidence for Late Polynesian Colonization of New Zealand: University of Waikato Radiocarbon Measurements." Radiocarbon 39, no. 2 (1997): 149–92. http://dx.doi.org/10.1017/s0033822200051997.

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We present radiocarbon determinations for 271 New Zealand archaeological samples measured at the University of Waikato Radiocarbon Dating Laboratory between 1975 and 1995. A discard protocol is applied to the series and the list culled to winnow the acceptable dates from those that may incorporate error. None of the 221 acceptable 14C determinations older than 600 bp (in the case of terrestrial samples) or 930 bp (in the case of marine and estuarine shell) extends beyond cal ad 1250. This conclusion supports the short chronology model of New Zealand prehistory presented by Anderson (1991).

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Journal articles on the topic 'Estuaries New Zealand'

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