Fishery Resources in Arid Zone Mangroves in Gulf of Kachchh, Gujarat, Northwest Coast of India

The finfish and shellfish resources were assessed quantitatively and qualitatively in regard to their abundance in creek waters at three sites within a period of two years, fi＇om January 1999 to December 2000, in the western mangrove areas of Kachchh. The catch rate varied from 0.69 to 6.99kg·h^-1. It was low during monsoon （July to October）, which could be due to the freshwater-flow-induced salinity reduction in all the sites. Among 38 species recorded, 5 were shellfish and 33 were finfish. The spawning period of fishes was found to be during summer and early monsoon period （May to August）. Surface water temperatures varied from 17℃ to 37 ℃. Salinity values varied from 34 to 44 and the pH ranged between 7 and 8.9. Variation in dissolved oxygen content was from 3.42 to 5.85 mL L^-1. The high fishery densities in these semi arid mangrove creek areas were recorded during monsoon and early winter season.

Marine Environment around Taiwan Coast

Coastal erosion is an island-wide problem in Taiwan; about 80% of the island＇s sandy coastline had suffered from erosion over the past few decades. Historically, with the specific tectonic environment and rapid uplifting rate, lots of sediment had been yielded and transported to the coastal area that resulted in an advancing shoreline. Taiwan economically moved from a developing country to a developed one; a lot of human intervention had been made along the island coast. These are the major factors on recent coastal erosion. Even actions such as building of stabilization structures may inadvertently increase erosion. Some intervention examples are chosen to address how human-induced change made the profound impact on coastal erosion in Taiwan. All the information serves to provide a better understanding of the coastal processes, and a better response to the erosion problem.

Environment-ecosystem dynamic processes of Spartina alterniflora salt-marshes along the eastern China coastlines

Spartina alterniflora is ecologically important in its original habitat; however, it has caused controversy since it was introduction into China(now it has been spreading rapidly on the Jiangsu, Shanghai, Zhejiang and Fujian coasts). The purpose of the present contribution is, on the basis of an analysis and synthesis of existing data sets, to evaluate the environmental-ecological effects of S. alterniflora, and to identify the relevant scientific problems that require further research in the future. Investigations have shown that, by reducing the near-bed shear stress associated with tidal currents, S. alterniflora can enhance the settling flux of suspended sediment and deposition rate on the tidal flats over the region. Further, field survey and analysis indicate that the S. alterniflora salt-marsh has a high primary production and provides a new type of habitat for the native benthic fauna. Some macro-, meio- and micro-fauna that used to live in the native salt-marshes have adapted to the S. alterniflora salt-marsh, forming a new ecosystem. Under the influences of a number of background factors, such as latitude variations and the coastal type, the environmental-ecological changes induced by Spartine have regional differentiations. To the north of Hangzhou Bay, with a high position of the pre-Holocene stratum base, a large width of the tidal flats, and a gentle bed slope, only a small part of the intertidal zone is occupied by the S. alterniflora salt-marsh. Here, the S. alterniflora salt-marshes mainly play a positive role in coastal protection and ecosystem functioning. In contrary, to the South of Hangzhou Bay, The pre-Holocene deposits are situated in relatively deeo waters, and the width of the tidal flats formed within coastal embayments is relatively narrow. As such, the expansion of S. alterniflora has squeezed the living space of other intertidal organisms, thus has a negative ecological effect. Therefore, the regional differentiation of the Spartina effects should be sufficiently considered in coastal development and management. Furthermore, in order to predict the future evolution of the S. alterniflora wetlands over the region, in addition to in situ monitoring and measurements, an ecosystem dynamic model should be established, taking into account the coupling of the rerrestrial and marine environmental-ecological processes.