Pacific oyster (Crassostrea gigas) is an invasive species which is able to adapt a wide range of environmental conditions. The study was conducted from August to October 2014. Objective of this study was to asses the distribution pattern, condition and gonad maturity length (Lm 50%) of the Pacific oysters in mangrove ecosystem of Cimanuk Delta, Indramayu, West Java, Indonesia.  This study was conducted in two adjacent areas:  Pabean Ilir and Pagirikan subdeltas. The oysters were collected from the estuary, brackish water ponds and the coastal flat, and  observed for their abundance, total length (mm) and weight (g). Morphological and histological methods were used to estimate the gonad maturity stage. Analysis were carried out to estimate distribution pattern and condition factor. According to the study, the Pacific oyster distribution pattern was clumped. The condition factor of the oyster was higher in the brackish water pond and estuary than in the coastal flat.  The Pacific oyster was found in gonad maturity stage (GMS) I – IV. The oyster was hermaprodit protandry and had length maturity (Lm 50%) of 47,46-48,43 mm (male) and 75,27-75,50  mm (female).

Bycatch is the catch of non-target fish, including what is brought to port which are not is main target of retain and what is discarded at fishing area. Sirib (a type of push net) and bubu (trap) are fishing gear to catch glass eel in the five rivers (both upriver and estuary) from Sukabumi, West Java. The research was conducted in July 2019 to January 2020. The aimed of this study to analyze the catch composition of glass eel from Cimandiri River. Result of the study shows that the catch composition from Cimandiri River consist of 8–9 species. However, catch composition of trap is lower than sirib/pushnet due to traps are more selective than sirib instead of the fishing location from the traps is in upriver.

Eel (Anguilla sp.) is one of the important commercial fish in some countries particularly in East Asian countries such as Japan, South Korea, China, and Taiwan. The need of eel fry or frequently called as glass eel still relies on the natural capture. The issue of natural captured fish is the high level of bacterial infections and diseases. The dependence of glass eel from the nature provides an indication of infections of parasites and bacteria in glass eel. The existence of parasites and bacteria as microorganisms which are potential as pathogenic agents in the cycle of eel culture can be a serious obstacle, so that the glass eel handling needs a particular attention since the capturing proses from the nature. Therefore, identification of parasites and bacteria in the capture location of glass eel was necessarily conducted in Pelabuhan Ratu Bay, Sukabumi, West Java. The glass eel sampling was conducted in May-June 2019, in 3 locations of estuary with the highest capture yield namely Cimandiri River, Cikaso River and Cibuni River. The number of samples taken were 30 eels at each river location with 2 replicates, so that the total eel samples which were taken were 180 eels. Identification of parasites was conducted by examination of ectoparasite and endoparasite and dentification of bacteria was conducted by conventional method (biochemical method). Based on the result of identification, there was no parasite found in the glass eel samples, while bacteria found as many as 12 species and 3 dominant species namely Listeria sp. found in 40 eel samples with prevalence of 22.2%, Aeromonas hydrophila found in 28 eel samples with prevalence of 15.6%, and Staphylococcus spp. found in 22 eel samples with prevalence of 12.2%.