Larval fish drift and distribution patterns were studied in the River Lohajang, a tributary of the River Jamuna, Bangladesh, during the monsoon seasons (June ‐ October) of 1992, 1993 and 1994. Larval fish drift peaks with the water levels of the River Jamuna. In all three years, the Indian carp, Catla catla, Labeo rohita L. and Cirrhinus mrigala, were associated with the first pulses, but were absent from drift samples after September. Hilsa species and other non‐identified fish species were found throughout the monsoon season. The highest larval fish densities were found in the upper strata of the river, near the shore. The drift densities of these fish became evenly distributed through time. Water turbidity probably influenced the vertical and horizontal distribution, and the absence of diel patterns. The most important species in the larval drift were Hilsa spp., followed by Labeo rohita L., Glossogobius giuris L. and Rasbora daniconius. Among the major carp, Labeo rohita was the dominant species, contributing 80‐90%. The impact of flood control programmes on the reproduction of riverine and larval fish drift is discussed.

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Grouper is an export product, the grouper market is not heard in the country, because most of its products are "sold" abroad alive to some countries such as Singapore, Japan, Hongkong, Taiwan, Malaysia, and the USA. Grouper production still relies on the catch from the sea, although it is now starting the restocking activities the development and growth of the results of these activities have not known the impact on the development of groupers stock. Meanwhile, high demand and economic value have an effect on the frequency of catch effort, so that early information on Grouper stock availability is needed, it is used as an initial step to create sustainable Grouper resource. The objective of this research is to get potential stock of Grouper of Situbondo waters by using Walter and Hilborn model to obtain maximum catch (CMY), catch effort (EMSY) and sustainable potential (Pe). This research uses the descriptive method and sampling technique is done by purposive sampling. The results showed that the value of CSMY 29.894.60,12 kg / year, EMSY 789.166 trip / year, the type of fishing gear is the standard catch tool, the intrinsic population growth rate of Grouper by 47.35% per year, the carrying capacity maximum of water (k) of 252537,451 kg / year, capture ability (q) of 0.0000003 and Grouper (Pe) resource potential of 126268,726 kg / year. While the potential for biomass reserves in 2030, the open access condition is 82,863.95 Kg, when compared to the potential condition of 2030 sustainable, only 49% is left. It is recommended to initiate synergies immediately between exploitation efforts and restocking efforts to create sustainable grouper resources.