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Abstract. Removal methods were used to estimate key fishery parameters, abundance and exploitation rate for five species of tropical sea cucumbers harvested by Indonesian fishers at Scott Reef, north-western Australia. Detailed catch records were kept by the traditional fishers over a period of 58 days as needed for this method, whereas effort was estimated from aerial surveillance. Concurrently, ,1007 artificial sea cucumber surrogates, were distributed and rewards were paid for recovered surrogates. Both datasets were analysed using the Huggins closed-population procedure in program MARK to obtain maximum-likelihood estimates. This procedure allowed inclusion of effort and tide covariates and an initial search phase followed by an exploitation phase. We accounted for extreme over-dispersion which is a common problem in fishery removal data. Our results strongly suggested that some surrogates became unavailable to the fishers. However, results from both datasets demonstrated strong evidence of extreme rates of exploitation on the shallow, drying reef-top habitat. Closed-removal or depletion methods are shown to be a viable method to estimate abundance and exploitation rate for sea cucumbers harvested with intense fishing pressure during a short fishing season.

To compensate the decline of the populations of temperate anguillid eels, tropical anguillid eels become getting attention of East Asian eel market in recent years. Many eel farms have been established in Java Island to culture tropical anguillid eels intending to export the products to East Asia. Since eel farming is reliant on wild-caught anguillid eels such as glass eels, elvers and yellow eels, these eel seeds have been captured in various places in Indonesia. However, it is still unknown that how much of tropical anguillid eels are caught as seeds for eel farming. This study showed two different patterns of the commodity chains of eel seeds from both Sukabumi Regency and Bengkulu Province to the eel farms in Java Island. Official catch statistics on anguillid eels found in both Sukabumi Regency and Bengkulu Province were also analyzed on their features and problems underlied. Considering the sustainable use of anguillid eel resources and critical stances on exploitation of eel seeds from all over the world, the Indonesian government should take an immediate action for developing the national catch statistics on anguillid eel fishery as soon as possible.

Oktaviani D, Triharyuni S, Nugroho D. Population parameters and bio-exploitation status of Indian mackerel (Rastrelliger kanagurta Cuvier, 1816) in Mayalibit Bay, Raja Ampat, Indonesia. Biodiversitas 20: 3545-3552. A small-scale fishery in Mayalibit bay, Raja Ampat is one among rare fisheries systems existing in Indonesia. The area already designated as a conservation zone, and Indian mackerel is the main target species by fishers. This species plays a significant role in supplying domestic food. Fisher harvest with a small wooden boat, no engine, one-night fishing using Petro-lamp, and harvested with a scoop net. Monthly based biological observations on population parameters were carried out from March 2011 to April 2012. The result shows that the fish landed with size from 10.0 to 27.0 cm, and 70% of the sample is within 21-23 cm length. Monthly length-weight relationships indicate b value statistically equal to 3. The average unsexed Fulton condition factor index is 1.516 + 0.13 and illustrates the fishes were in suitable environmental conditions. The growth rate (K) is estimated at 0.97, while length infinity (L∞) is 28.4 cm. To evaluate the fishery, repeated observation of fishing in Mayalibit bay conducted in 2016. A productivity and susceptibility analysis was applied to predict its bio-exploitation status, and the results indicate that harvest levels are relatively at low-to-medium risk. Nevertheless, most of the fish caught in the bay by traditional knowledge consisted of mature cohorts while limited desk study to semi-industrial fishing targetted the same species in surrounding waters indicated that a significant proportion of undersize or immature individuals are in their landing. This phenomenon suggested that managing the existing local knowledge could significantly contribute to maintaining sustainable spawning stocks in the conservation zone.

Suaka perikanan merupakan perangkat dalam pengelolaan sumber daya ikan yang sebagian besar dilakukan di perairan umum daratan. Tujuan penelitian ini adalah untuk mengetahui upaya konservasi keanekaragaman hayati ikan perairan umum daratan di Pulau Jawa. Penelitian ini dilakukan di Jawa Barat,Jawa Tengah, dan Jawa Timur dilakukan pada bulan April sampai Nopember 2007. Metode yang digunakan adalah survei lapang, wawancara, dan studi pustaka. Hasil penelitian menunjukan bahwa persepsi yang berbeda terhadap suaka perikanan pada waduk akan memberikan status pengelolaan yang berbeda. Upaya konservasi yang telah dilakukan di Pulau Jawa berupapembentukan suaka perikanan yang menjadi bagian dari pengelolaan waduk dan bentuk dari kearifan lokal. Pengembangan suaka perikanan yang sudah ada memerlukan peraturan yang efisien dan efektif karena belum dikelola denganbaik.Reservat is a part of fisheries resources management and largely conducted in the inland open waters. The research objective was to determine the conservation of biodiversity of inland open waters on the island of Java. The study was conducted in West Java, Central Java, and East Java in April to November 2007. The method used is the field surveys, interviews, and literaturereview. The results showed that the different perceptions of reservat fishery in the reservoir will provide a different management status. Conservation efforts that have been conducted on the island of Java in the form of the establishment offisheries reserves that are part of reservoir management and forms of local wisdom. Development of existing reservat fisheries regulations requires an efficient and effective because it has not managed properly.