Dredging fundamentally reshapes the ecological significance of 3D terrain features for fish in estuarine seascapes

Abstract Context Landscape modification alters the condition of ecosystems and the structure of terrain, with widespread impacts on biodiversity and ecosystem functioning. Seafloor dredging impacts a diversity of flora and fauna in many coastal landscapes, and these processes also transform three-dimensional terrain features. The potential ecological significance of these terrain changes in urban seascapes has, however, not been investigated. Objectives We examined the effects of terrain variation on fish assemblages in 29 estuaries in eastern Australia, and tested whether dredging changes how fish associate with terrain features. Methods We surveyed fish assemblages with baited remote underwater video stations and quantified terrain variation with nine complementary metrics (e.g. depth, aspect, curvature, slope, roughness), extracted from bathymetry maps created with multi-beam sonar. Results Fish diversity and abundance were strongly linked to seafloor terrain in both natural and dredged estuaries, and were highest in shallow waters and near features with high curvature. Dredging, however, significantly altered the terrain of dredged estuaries and transformed the significance of terrain features for fish assemblages. Abundance and diversity switched from being correlated with lower roughness and steeper slopes in natural estuaries to being linked to features with higher roughness and gentler slopes in dredged estuaries. Conclusions Contrasting fish-terrain relationships highlight previously unrecognised ecological impacts of dredging, but indicate that plasticity in terrain use might be characteristic of assemblages in urban landscapes. Incorporating terrain features into spatial conservation planning might help to improve management outcomes, but we suggest that different approaches would be needed in natural and modified landscapes.

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Contrasting effects of mangroves and armoured shorelines on fish assemblages in tropical estuarine seascapes

ICES Journal of Marine Science ◽

10.1093/icesjms/fsz007 ◽

2019 ◽

Vol 76 (4) ◽

pp. 1052-1061 ◽

Cited By ~ 7

Author(s):

Christopher J Henderson ◽

Ben L Gilby ◽

Thomas A Schlacher ◽

Rod M Connolly ◽

Marcus Sheaves ◽

...

Keyword(s):

Fish Assemblages ◽

Urban Expansion ◽

Ecological Impacts ◽

Spatial Context ◽

Fish Diversity ◽

Mangrove Forests ◽

Habitat Types ◽

Tropical Estuarine ◽

Eastern Australia ◽

Close Proximity

Abstract Coastal seascapes are composed of a diversity of habitats that are linked in space and time by the movement of organisms. The context and configuration of coastal ecosystems shapes many important properties of animal assemblages, but potential seascape effects of natural and artificial habitats on nearby habitats are typically considered in isolation. We test whether, and how, the seascape context of natural and urban habitats modified fish assemblages across estuaries. Fish were sampled with underwater videos in five habitat types (mangroves, rock bars, log snags, unvegetated sediments, armoured shorelines) in 17 estuaries in eastern Australia. Different habitats supported distinct fish assemblages, but the spatial context of mangroves and armoured shorelines had pervasive ecological effects that extended across entire estuaries. In most estuarine habitats, fish diversity and abundance was greatest when they were in close proximity of mangroves, and decreased due to the proximity of armoured shorelines. Many cities are centred on estuaries, and urban expansion is often associated with the fragmentation of mangrove forests. Our findings emphasize that these transformations of urban estuarine landscapes are likely to propagate to broader ecological impacts detectable in multiple habitats beyond mangrove forests.

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Estuarine characteristics, water quality and heavy metal contamination as determinants of fish species composition in intermittently open estuaries

Marine and Freshwater Research ◽

10.1071/mf15409 ◽

2017 ◽

Vol 68 (5) ◽

pp. 941 ◽

Cited By ~ 5

Author(s):

K. O'Mara ◽

A. Miskiewicz ◽

M. Y. L. Wong

Keyword(s):

Water Quality ◽

Species Composition ◽

Fish Species ◽

Metal Contamination ◽

Fish Assemblages ◽

Anthropogenic Activities ◽

Estuarine Fish ◽

Fish Diversity ◽

Eastern Australia ◽

Fish Species Composition

Estuaries are critical aquatic environments that are used by many fish during their life cycle. However, estuaries often suffer from poor water quality as a result of anthropogenic activities. Fish diversity studies in estuaries are common, although few have examined whether correlations exist between water quality, metal contamination and fish assemblages. In the present study we investigated the effect of abiotic conditions, heavy metals and estuary characteristics on the abundance, diversity and composition of fish in four intermittently open estuaries along the Illawarra coast of south-eastern Australia. The heterogeneity of environmental conditions was reflected in the fish assemblages in each estuary. Environmental variables predicted fish species composition, and estuaries in particularly poor condition contained few species (estuarine residents) in high abundance, indicating their ability to acclimatise and survive in conditions that are hostile to other species. Overall, these findings demonstrate that estuarine fish assemblages may be useful indicators of estuary condition and reveal the importance of managing anthropogenic activities in the surrounding catchment to improve water quality so that biodiversity of fish can be restored in these estuarine environments.

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FISH DIVERSITY IN THE DOWNSTREAM REGION OF CIPANAS RIVER INDRAMAYU, WEST JAVA INDONESIA

Zoo Indonesia ◽

10.52508/zi.v29i1.3978 ◽

2020 ◽

Vol 29 (1) ◽

Author(s):

Titin Herawati ◽

Gema Wahyudewantoro ◽

Yuli Andriani ◽

Heti Herawati ◽

Naomi Masnida Yunisia Siregar

Keyword(s):

Water Quality ◽

Census Data ◽

Fish Assemblages ◽

Survey Methods ◽

Upstream Region ◽

Fish Diversity ◽

West Java ◽

Fish Collection ◽

Java Sea ◽

Downstream Area

Cipanas River is one river in West Java where its upstream region in Tampomas Mountain, Sumedang and it is emptied into the Java Sea, Indramayu. The study was aimed to investigate fish diversity in the downstream area of Cipanas River. The study was conducted by survey methods with census data collection techniques, taken place at 3 stations of Santing, Tempalong, and Cemara of Indramayu Regency. The parameters measured consisted water quality and fish assemblages. Water quality was measured referring to standard laboratory protocol, and fish collection was made by case net with different mesh sizes. The results showed that water quality conditions of the Cipanas River downstream was suitable for inhabiting fishes. There were as many as 548 individual fishes caught belonging to 21 species, 16 genera, and 14 families. Fish diversity was categorized as medium with 1.6 ≤ H ’≤ 2.2 indicating fairly good community structure, and the Evenness index was 0.81 ≤ E ≤ 0.86 to show highly evenly distributed.

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Corrigendum to: Depth-related composition and structuring of tropical riverine fish assemblages revealed by baited video

Marine and Freshwater Research ◽

10.1071/mf16278_co ◽

2017 ◽

Vol 68 (10) ◽

pp. 1976

Author(s):

Stephen Cousins ◽

Mark J. Kennard ◽

Brendan C. Ebner

Keyword(s):

Fish Assemblages ◽

Cost Effective ◽

Water Clarity ◽

Sampling Effort ◽

Underwater Video ◽

Video Footage ◽

Eastern Australia ◽

North Eastern ◽

Lutjanus Argentimaculatus ◽

Riverine Fish

The aim of the present study was to determine whether boat-based deployment of remote underwater video cameras is effective for surveying fish assemblages in the deepest reaches of two large tropical rivers in north-eastern Australia. In addition, we compared fish assemblages recorded on baited versus unbaited cameras, and evaluated the sampling effort (duration of recording) required to estimate fish assemblages using remote underwater videos. We found that fish assemblages differed according to the depth, with statistically significant differences largely attributable to the prevalence of small-bodied species (Ambassis sp., Melanotaenia sp. and Pseudomugil signifer recorded in shallow (0.4–2.0m) and intermediate (2.1–4.9m) depths, and larger-bodied fish species (>10cm TL), such as Lutjanus argentimaculatus, Mesopristes argenteus and Caranx sexfasciatus, in deep water (>5.0m). Estimates of fish assemblage attributes generally stabilised after 60min recording duration, suggesting that interrogation of video footage beyond this duration may not be cost-effective. We conclude that depth is an important consideration when surveying large and deep river fish assemblages and that where water clarity is favourable, underwater video provides one of the means by which an assemblage can be investigated across the entire depth profile.

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No detrimental effects of desalination waste on temperate fish assemblages

ICES Journal of Marine Science ◽

10.1093/icesjms/fsaa174 ◽

2020 ◽

Author(s):

Sasha K Whitmarsh ◽

Greg M Barbara ◽

James Brook ◽

Dimitri Colella ◽

Peter G Fairweather ◽

...

Keyword(s):

Species Diversity ◽

Fish Assemblages ◽

Waste Product ◽

Ecological Impacts ◽

Global Changes ◽

Reference Sites ◽

Desalination Plant ◽

Saline Waste ◽

Temperate Fish ◽

The Impact

Abstract Water resources are becoming increasingly scarce due to population growth and global changes in weather patterns. Desalination plants that extract freshwater from brackish or seawater are already being used worldwide, with many new plants being developed and built. The waste product from the extraction processes has an elevated salt concentration and can potentially cause substantial impacts to local marine flora and fauna. The present study assesses the impact of saline waste from a 100 GL/year desalination plant on southern Australian temperate fish assemblages, using baited remote underwater video. The study compared four reference sites to the impact site (desalination outfall) and found no evidence that the saline waste was having a detrimental effect on fish assemblages in proximity to the outfall, with species diversity and abundance comparable to those observed at reference sites. However, species diversity and abundance varied across geographical location, protection from fishing pressure, and reef type. Our study is one of the few assessing the ecological impacts of saline waste discharged from a large desalination plant and shows no decrease in fish diversity or abundance, which is the response typically associated with the negative impacts of anthropogenic activities on fish assemblages.

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Spatial and temporal variation in fish assemblages in three small unpolluted estuarine rivers and associated lagoons in Kouchibouguac National Park, southern Gulf of St. Lawrence, Canada

The Canadian Field-Naturalist ◽

10.22621/cfn.v129i2.1692 ◽

2015 ◽

Vol 129 (2) ◽

pp. 121 ◽

Cited By ~ 4

Author(s):

Amanda M. Bremner ◽

D. A. Methven ◽

Kelly R. Munkittrick ◽

Katherine A. Frego

Keyword(s):

Water Temperature ◽

Dominant Species ◽

Gasterosteus Aculeatus ◽

Fish Assemblages ◽

Vegetation Coverage ◽

Spatial And Temporal Variation ◽

Fish Diversity ◽

Spatial Gradient ◽

Scaling Analysis ◽

Pungitius Pungitius

Estuaries have among the highest primary production rates of ocean waters and provide essential habitat for many organisms. Recognition of the need to conserve these critical habitats is coupled with the need for baseline data to allow assessment of ecosystem changes. This study compares natural variations in, and correlations between, the composition of fish assemblages and environmental factors at several sites over two years in three rivers emptying into estuaries in the southern Gulf of St. Lawrence, Canada. Fish diversity and abundance were determined by beach seining and related to water temperature, salinity, substrate, and vegetation. From May to September 2000 (14 sites) and May to August 2001 (15 sites), 20 fish species were collected, seven of which accounted for 98% of the total catch. The dominant species, Mummichog (Fundulus heteroclitus), represented 44% of the catch. Its abundance and that of the other dominant species — Threespine Stickleback (Gasterosteus aculeatus) 16%, Blackspotted Stickleback (G. wheatlandi) 13%, Banded Killifish (F. diaphanus) 12%, Fourspine Stickleback (Apeltes quadracus) 7%, Atlantic Silverside (Menidia menidia) 4%, and Ninespine Stickleback (Pungitius pungitius) 2% — differed significantly both spatially and temporally. Multidimensional scaling analysis showed a spatial gradient in abundance from upstream to lagoon sites and a temporal gradient from spring to fall. Upstream sites were low in salinity and had a higher organic content and a higher proportion of silt–clay in the sediment. Variation within fish populations was related to site and seasonal changes in environmental conditions and species’ tolerance of water temperature, salinity, vegetation coverage, and fine sediments.

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Three-dimensional potential field modelling of a multi-vent maar-diatreme — The Lake Coragulac maar, Newer Volcanics Province, south‐eastern Australia

Journal of Volcanology and Geothermal Research ◽

10.1016/j.jvolgeores.2012.05.002 ◽

2012 ◽

Vol 235-236 ◽

pp. 70-83 ◽

Cited By ~ 29

Author(s):

Teagan N. Blaikie ◽

Laurent Ailleres ◽

Ray A.F. Cas ◽

Peter G. Betts

Keyword(s):

Potential Field ◽

Three Dimensional ◽

Field Modelling ◽

South Eastern ◽

Eastern Australia ◽

Potential Field Modelling ◽

South Eastern Australia

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Twentieth Century Winter Changes in Southern Hemisphere Synoptic Weather Modes

Advances in Meteorology ◽

10.1155/2011/353829 ◽

2011 ◽

Vol 2011 ◽

pp. 1-16 ◽

Cited By ~ 11

Author(s):

Jorgen S. Frederiksen ◽

Carsten S. Frederiksen

Keyword(s):

Growth Rate ◽

Southern Hemisphere ◽

Western Australia ◽

Three Dimensional ◽

Storm Track ◽

Intraseasonal Oscillation ◽

Low Frequency ◽

Winter Rainfall ◽

Cloud Band ◽

Eastern Australia

During the last sixty years, there have been large changes in the southern hemisphere winter circulation and reductions in rainfall particularly in the southern Australian region. Here we examine the corresponding changes in dynamical modes of variability ranging from storm tracks, onset-of-blocking modes, northwest cloud-band disturbances, Antarctic low-frequency modes, intraseasonal oscillations, and African easterly waves. Our study is performed using a global two-level primitive equation instability-model with reanalyzed observed July three-dimensional basic states for the periods 1949–1968, 1975–1994, and 1997–2006. We relate the reduction in the winter rainfall in the southwest of Western Australia since the mid-1970s and in south-eastern Australia since the mid-1990s to changes in growth rate and structures of leading storm track and blocking modes. We find that cyclogenesis and onset-of-blocking modes growing on the subtropical jet have significantly reduced growth rates in the latter periods. On the other hand there is a significant increase in the growth rate of northwest cloud-band modes and intraseasonal oscillation disturbances that cross Australia and are shown to be related to recent positive trends in winter rainfall over northwest Western Australia and central Australia, in general. The implications of our findings are discussed.

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Dams and the fish fauna of the Neotropical region: impacts and management related to diversity and fisheries

Brazilian Journal of Biology ◽

10.1590/s1519-69842008000500019 ◽

2008 ◽

Vol 68 (4 suppl) ◽

pp. 1119-1132 ◽

Cited By ~ 372

Author(s):

AA. Agostinho ◽

FM. Pelicice ◽

LC. Gomes

Keyword(s):

Fish Assemblages ◽

Fish Fauna ◽

Neotropical Region ◽

Life Cycles ◽

Fish Diversity ◽

Negative Consequences ◽

Long Distance ◽

Management Actions ◽

Composition And Structure ◽

Almost All

Reservoirs have been built in almost all of the hydrographic basins of Brazil. Their purposes include water supply for cities, irrigation and mainly, generation of electricity. There are more than 700 large dams and associated reservoirs in the large rivers of the country. These reservoirs favor local and regional economic development, but they also bring serious and irreversible alterations in the natural hydrologic regime of rivers, affecting habitat quality and the dynamics of the biota. In the impounded area, the main impact is the change from lotic to lentic water, which influences aquatic fauna, including fishes. Impacts of reservoirs present relevant spatiotemporal variations. Immediately after reservoir formation, fish species richness usually increases due to incorporation of surrounding habitats, but richness decreases as reservoirs age. However, impacts downstream of dams appear to be similar or stronger than those that occur within the reservoir. Dams promote discharge control, altering the seasonal cycles of floods. These effects are augmented when dams are constructed in cascades. Therefore, dams profoundly influence composition and structure of fish assemblages. Most affected species are the rheophilics and long distance migratory that require distinct habitats to fulfill their life cycles. Populations of migratory species may collapse or even disappear in intensely regulated stretches. Management actions taken to minimize impacts of dams in Brazil historically considered construction of fish passages, fishery control and stocking. The results of these actions are questionable and/or with clear failures. In this paper, we give emphasis to the Paraná River basin, the most affected by dams in Brazil. We describe some patterns in the alteration and decline in fish diversity in areas influenced by dams. We also discuss negative consequences in the fishery and ecosystems functioning. Finally, we argue the relevance and the success of the management actions taken and present some suggestions to improve conservation of the ichthyofauna in South American basins influenced by dams.

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