The Boao coastal system along the eastern coast of Hainan Island is a dynamic delta-tidal inlet-barrier formed during the late Holocene. The delta developed inside a shallow lagoon barred by a sandy barrier with a nar...The Boao coastal system along the eastern coast of Hainan Island is a dynamic delta-tidal inlet-barrier formed during the late Holocene. The delta developed inside a shallow lagoon barred by a sandy barrier with a narrow, shallow tidal inlet opening. Two major distributary channels separated by small islands characterize the delta. The lagoon is silting up receiving and trapping sediments from both the river and, in minor measure during storms, through the tidal inlet opening and barrier washovers. The barrier at the tidal inlet is highly dynamic and changes its form, accreting (migrating spit) against the inlet during fair-weather conditions and being eroded during storms and river floods. The delta has almost completely filled the lagoon and major concerns exist on the effect that ongoing large development plans may have on the environment. These concerns include the effect on floods and rate of siltation once banks of the islands have been stabilized and floodwater and sediment load are impeded from spreading over the lowlands, and the effect of increasing pollutant loads from the new facilities on the ecosystems of the increasingly restricting lagoon water and on the seashores.展开更多
Fishways are being provided more regularly than ever before and new designs are needed to provide passage for whole fish communities.Despite recent progress,fishways have frequently performed poorly,especially for sma...Fishways are being provided more regularly than ever before and new designs are needed to provide passage for whole fish communities.Despite recent progress,fishways have frequently performed poorly,especially for small-bodied fish(i.e.10-100 mm long),which can form large aggregations below stream barriers.This was the genesis for the development of the cone fishway design,a new style of technical fishway which consists of a series of pre-fabricated cone-shaped concrete baffles installed laterally within a concrete channel.The cone design arose from the need to install rock ramp fishways at remote sites where rock was unavailable and where maintenance would be infrequent.The objective of the present study was to evaluate the suitability of the new cone fishway design to provide passage for small-bodied diadromous species(i.e.<100 mm long).Cone fishways were evaluated at three low head(e.g.<3 m high)case-study sites in tropical and temperate Australia and in total,45 species and 28,556 fish were collected.There was passage of a broad range of the target size-classes of small-bodied fish and individuals as small as nine mm could ascend.However,further work is needed to quantify the proportion of the small-bodied fish population in the river downstream which find and pass through the cone fishways.The most suitable experimental application of the cone fishway is at sites where there is:(i)a narrow(e.g.<0.4 m)headwater range,and(ii)where passage of small-bodied fish is a major ecological priority.Cone fishways provide a useful and novel option to improve passage of small-bodied fish,at appropriate sites,and contribute to a contemporary vision of restoration of whole fish communities.展开更多
文摘The Boao coastal system along the eastern coast of Hainan Island is a dynamic delta-tidal inlet-barrier formed during the late Holocene. The delta developed inside a shallow lagoon barred by a sandy barrier with a narrow, shallow tidal inlet opening. Two major distributary channels separated by small islands characterize the delta. The lagoon is silting up receiving and trapping sediments from both the river and, in minor measure during storms, through the tidal inlet opening and barrier washovers. The barrier at the tidal inlet is highly dynamic and changes its form, accreting (migrating spit) against the inlet during fair-weather conditions and being eroded during storms and river floods. The delta has almost completely filled the lagoon and major concerns exist on the effect that ongoing large development plans may have on the environment. These concerns include the effect on floods and rate of siltation once banks of the islands have been stabilized and floodwater and sediment load are impeded from spreading over the lowlands, and the effect of increasing pollutant loads from the new facilities on the ecosystems of the increasingly restricting lagoon water and on the seashores.
基金Production of this paper was supported by the Applied Aquatic Ecology writing retreat initiativeSampling in Queensland undertaken under Animal Ethics Authorisation No.CA2014/08/798.
文摘Fishways are being provided more regularly than ever before and new designs are needed to provide passage for whole fish communities.Despite recent progress,fishways have frequently performed poorly,especially for small-bodied fish(i.e.10-100 mm long),which can form large aggregations below stream barriers.This was the genesis for the development of the cone fishway design,a new style of technical fishway which consists of a series of pre-fabricated cone-shaped concrete baffles installed laterally within a concrete channel.The cone design arose from the need to install rock ramp fishways at remote sites where rock was unavailable and where maintenance would be infrequent.The objective of the present study was to evaluate the suitability of the new cone fishway design to provide passage for small-bodied diadromous species(i.e.<100 mm long).Cone fishways were evaluated at three low head(e.g.<3 m high)case-study sites in tropical and temperate Australia and in total,45 species and 28,556 fish were collected.There was passage of a broad range of the target size-classes of small-bodied fish and individuals as small as nine mm could ascend.However,further work is needed to quantify the proportion of the small-bodied fish population in the river downstream which find and pass through the cone fishways.The most suitable experimental application of the cone fishway is at sites where there is:(i)a narrow(e.g.<0.4 m)headwater range,and(ii)where passage of small-bodied fish is a major ecological priority.Cone fishways provide a useful and novel option to improve passage of small-bodied fish,at appropriate sites,and contribute to a contemporary vision of restoration of whole fish communities.
