Cikaso and Cimandiri estuaries are well known as the central area of glass eel fisheries in Sukabumi Regency. Local fishermen catch glass eels using two main fishing gears, namely traps and lift nets. Although both fishing gears' target operation is glass eels, many other fish species are also caught as bycatch. The present study aimed to identify glass eels and bycatch ichthyofauna in glass eel fisheries of the Cikaso and Cimandiri estuaries, Sukabumi. The research was carried out monthly from November 2020 to January 2021. Glass eels fishing gears collected a total of 21 fish species belonging to 15 families in both estuaries. According to the percentage ano-dorsal length measurement to total length (AD/TL), 3 species of glass eel were identified, i.e. Anguilla bicolor bicolor, A. nebulosa, and A. marmorata. These three species were the most abundant fish catches in both estuaries. More than 18 bycatch ichthyofauna were recorded and most of them are economically important fish, such as Ambassidae, Eleotridae, Engraulidae, Gobiidae, and Polinemidae. To sustain fishery management, the recording bycatch from glass eel fishery in the Cikaso and Cimandiri estuaries is necessary to be done regularly because they contribute to fishing mortality.
This study aims to analyze the species diversity, distribution and status of fish found in the coastal waters of Banten Bay. Samplings were carried out 7 times at three locations namely Cengkok coastal waters (on February-March 2019), Bojonegara coastal waters (January-February, August-September 2020), and Kemayungan-Linduk coastal waters (February-April 2021) of the Banten Bay, using gill nets, trammel net, cast net, hand-line, beach seine, and mini trawl. Results of this study showed that the fish caught in the Banten Bay coastal waters consisted of 111 species, distributed at the three areas, namely Cengkok (32 species), Bojonegara (58 species), and Kemayungan-Linduk coastal waters (51 species). The diversity, eveness, and dominance indices were 2.185 - 3.763, 0.630 - 0.781, and 0.072 - 0.233 respectively, indicating the medium-high species diversity. These fish were spreading in marine water, fresh water, estuary, freshwater and estuary, marine and estuary, and marine, estuary and freshwater. The common species found at the study location were Ellochelon vaigiensis, Planiliza subviridis, and Leiognathus equula. In general, most of the fish found in Banten Bay were classified as least concern (LC), while two species were vulnerable (VU), one species was near threatened (NT), and ones species was endangered species (EN).
The sustainability of amphidromous fishes is determined by the success of the larval recruitment process from marine to freshwaters habitats. This study aimed to determine the recruitment pattern of freshwater amphidromous fish to the Cimaja River estuary, Palabuhanratu Bay in terms of season and daily. Amphidromous fish were caught monthly on the 25th of Hijri or waning crescent from December 2020 to August 2021. Sampling in one whole day with observation intervals every 4 hours was carried out in June 2021 to reveal the time of larvae and juveniles of the amphidromous fish recruit to the Cimaja River estuary. A total of 13 species of amphidromous fishes representing five genera and two families was captured. The recruitment of amphidromous fishes into the Cimaja River occurs between the peak of the rainy season to dry season. Generally, amphidromous recruit into the estuary waters of the Cimaja River is at the juvenile stage (11.9-21.8 mm body length). However, the recruitment of some amphidromous fish species appears at the postflexion stage (6.9-11.9 mm BL). Based on diel observations, larvae and juveniles of amphidromous fish are generally preferred to recruit to the Cimaja River estuary in the early morning (03:00 am) and afternoon (03:00 pm). Recruitment of amphidromous fish larvae to the Cimaja River follows a semi-diurnal tidal cycle which is a tidal type in Palabuhanratu Bay. Amphidromous fishes use tidal flux to recruit and migrate upstream of the Cimaja River through estuaries.
Larvae and juveniles of bully sleepers are the primary targets for the local community surrounding Cisolok River, and this traditional fishing activity is called nyalawean. The present study aims to uncover fish larval diversity and recruitment of bully sleepers in the Cisolok river estuary. Fish sampling using a lift net was conveyed monthly from December 2020 to February 2021. Fish specimens were identified to the lowest taxon through a morphological approach and DNA Barcoding. Catch per unit effort measured the abundance of fish larvae and juveniles (CPUE, Ind.h−1). Only one species was found during the study period, namely Bunaka gyrinoides. A total of 7,353 larvae and juveniles of B. gyrinoides were captured, consisting of flexion (45 individuals; 4-5.9 mm BL), postflexion (6,887; 6-11 mm BL), and early juvenile (441; 11.1-14.8 mm BL). Postflexion larvae were the most abundant specimens, contributing 88.4-95.5%; 96-81.1%, 94.2-97.8% to the total catches in December, January, and February. Larvae and juveniles were more abundant during daylight (671-1591 Ind.h-1) rather than nighttime (147-567 Ind.h-1). These findings indicate that bully sleepers recruit and migrate upstream into the freshwater area of the Cisolok River during the day and nighttime synchronized with the tidal fluxes.
Cimaja estuary has been well known as a fishing ground for fish larvae and juveniles of amphidromous fishes. The local people call this group of fish impun and collect them frequently for consumption. However, no information about fish diversity and recruitment of amphidromous goby in the Cimaja estuary is known. Therefore, this study aims to reveal species composition, recruitment pattern, and estimation of the abundance of fish larval and juvenile amphidromous goby in the Cimaja estuary day and night. Sampling was performed monthly during the new moon period from December 2020 to February 2021. Fish specimens were identified to the lowest taxon level through a morphological approach. A total of 23,331 larvae and juveniles of Gobiidae were collected, and most of them were Sicyopterus spp. The juvenile stage (11.9-21.8 mm BL) comprised 95.6% of the catches, postflexion larvae (6.9-11.8 mm BL) contributed 3.5% to the total yield and 0.9% of the total capture consisting of flexion larvae (3.9-6.8 mm BL). Gobiid fishes are preferred to recruit and migrate into the Cimaja river during the day than at night time (p < 0.05), and their movement to the upstream are synchronized with the tidal cycle.
The biological aspect is a piece of basic information that is commonly presented in assessing the level of environmental friendliness of fishing gear or fishing vessel. This study was conducted to analyze the biological aspects of the main catch of the troll line at the Palabuhanratu Fishing Port, Sukabumi, Indonesia. The biological aspects analyzed consisted of length frequency distribution, length-weight relationship, to the average feasibility status of the caught target fish. There were three main target commodities for fishing from the troll line that was identified during the research activity, namely yellowfin tuna (Thunnus albacares), skipjack tuna (Katsuwonus pelamis), and frigate tuna (Auxis thazard). A total of 14 troll line fleets were obtained as a source of research data based on the accidental sampling method. The total number of 1404 fish consisting of 480 yellowfin tuna, 475 skipjack tuna, and 449 frigate tuna were obtained as research data objects. The stratified random sampling method was used in determining the observed sample fish data. Yellowfin tuna were distributed at size 29 – 148 cm, skipjack tuna at size 29 – 88 cm, and frigate tuna at size 23 – 82 cm. Analysis of the length-weight relationship showed a negative allometric growth pattern in the three main fishing target commodities. The analysis of the feasibility of the average fish caught based on compared of L50% to ½ L∞ shows that the average size of tuna and frigate tuna caught is undersize for catching, while the average skipjack caught has reached a legal size. The results of this study indicate that there is a need for a review of the use of fishing hooks in the fishing activity of the troll line fishing fleet. Increasing the hook size can be used to avoid catching fish that are at a size that is not suitable for catching.
Research on zooplankton assemblage is indispensable for understanding food web dynamics in marine ecosystems. In this study, we elucidated the composition, spatio-temporal distributions and community structure of zooplankton on the sea grass ecosystem of Panggang and Semak Daun Islands, Kepulauan Seribu National Park. Sampling was conducted monthly at fixed stations by vertical tows of 53 μm plankton net from February 2018 to March 2019. During the study period, a total of 52 genera belonging to 38 families of zooplankton were collected. Copepods and protozoans dominated in the zooplankton communities in both sea grass areas. No significant difference was observed in abundance of zooplankton between two sea grass areas of both islands (p > 0.05), however there were a relatively few significant differences of between day and night time catches of zooplankton (p < 0.05). Day time zooplankton was less abundant than night time. Canonical correspondence analysis underlines that zooplankton assemblages were significantly affected by environmental parameters such as salinity, dissolved oxygen, turbidity, and the percentage of sea grass cover. Moreover, the abundance and zooplankton assemblages were well matched with chlorophyll-a concentrations. Since early stage of fishes feeds directly on the zooplankton assemblage, our findings support that sea grass ecosystem plays an important role as a nursery ground for marine fishes.
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