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

Zoo Indonesia ◽  
2020 ◽  
Vol 29 (1) ◽  
Author(s):  
Titin Herawati ◽  
Gema Wahyudewantoro ◽  
Yuli Andriani ◽  
Heti Herawati ◽  
Naomi Masnida Yunisia Siregar

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.

2017 ◽  
Vol 68 (5) ◽  
pp. 941 ◽  
Author(s):  
K. O'Mara ◽  
A. Miskiewicz ◽  
M. Y. L. Wong

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.


PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242017
Author(s):  
Milton S. Love ◽  
Mary M. Nishimoto ◽  
Scott Clark ◽  
Li Kui ◽  
Azivy Aziz ◽  
...  

Offshore oil and gas platforms have a finite life of production operations. Once production ceases, decommissioning options for the platform are assessed. The role that a platform’s jacket plays as fish habitat can inform the decommissioning decision. In this study, conducted along the crossbeams of a California platform jacket and using an ROV, we compared estimates of fish diversity and densities determined from a targeted “biological” survey with those from a replicated “structural” survey. We found that the water column fish species assemblages characterized by the two methods were similar. By contrast, the two survey methods yielded different species assemblages inhabiting the crossbeam at the platform jacket base. This difference occurred because, at least off California, the platform jacket base species diversity tends to be highest where the bottom crossbeam is undercut, creating sheltering sites for many species. Because the structural method inadequately imaged the seafloor-crossbeam interface, particularly where a gap occurred between crossbeam and seafloor, substantial numbers of fishes were not visible. While we cannot extrapolate from this study to all platforms’ worldwide, it is clear that routine platform structural integrity surveys may be a valuable source for opportunistic marine community surveys. Intentional planning of the structural survey to incorporate relatively minor variations (e.g., maintaining fixed ROV distance from the infrastructure and consistent 90° camera angle) coupled with a deliberate consideration of the platform ecology (e.g., positioning the ROV to capture the seafloor-crossbeam interface) can substantially improve the effects on fish assemblage assessments from routine structural surveys without compromising the integrity assessment. We suggest that these biases should be both acknowledged and, understood when using routine structural surveys to inform platform ecology assessment. Additional consideration may be given to structural surveys that incorporate incremental adjustments to provide better data applicability to biological assessments.


2022 ◽  
Author(s):  
Hayden P. Borland ◽  
Ben L. Gilby ◽  
Christopher J. Henderson ◽  
Rod M. Connolly ◽  
Bob Gorissen ◽  
...  

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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