Abundance indices based on nominal CPUE do not take into account confounding factors such as fishing strategy and environmental conditions, that can decouple any underlying abundance signal in the catch rate. As such, the assumption that CPUE is proportional to abundance is frequently violated. CPUE standardisation is one of the common analyses applied. The aims of this paper were to provide a statistical modelling framework for conducting CPUE standardisations using the Observer Program data for bigeye tuna, yellowfin tuna, albacore and southern bluefin tuna, and provide a comparison in the trends between the nominal CPUEs and their standardised indices obtained. The CPUE standardisations were conducted on the Observer Program collected between 2005 and 2007, by applying GLM analysis using the Tweedie distribution. The results suggested that year, area, HBF and bait factors significantly influenced the nominal CPUEs for the four tuna species of interest. Some extreme peaks and troughs in the nominal time series were smoothed in the standardised CPUE time series. The high degree of temporal variability that is still shown in the standardised CPUE trends suggests that the data are too sparse to give any meaningful indication of proxy abundance. Nevertheless, this may also suggest that variables used in the GLMs do not sufficiently account for all of the confounding factors, or abundance may indeed be truly variable.

Tingginya permintaan pasar terhadap udang jerbung mengakibatkan aktivitas penangkapannya berlangsung secara terus-menerus sepanjang tahun sehingga mengancam kelestariannya. Penelitian karakteristik populasi merupakan salah satu dasar utama dalam merumuskan pengelolaan menuju pemanfaatannya secara lestari. Tujuan penelitian ini adalah untuk mengetahui karakteristik populasi udang jerbung di perairan Cilacap dan sekitarnya. Penelitian dilakukan dari bulan Januari sampai dengan Nopember 2013 dengan metode survey. Hasil penelitian menunjukkan bahwa rata-rata ukuran panjang pertama kali matang kelamin (Lm) udang jerbung di perairan Cilacap dan sekitarnya adalah pada panjang karapas 38,3 mm dan musim pemijahan berlangsung sepanjang tahun dengan puncaknya pada bulan Januari. Laju pertumbuhan udang jerbung jantan adalah 1,00 per tahun dan panjang karapas maksimum (L ) adalah 40,7 mm serta untuk udang betina didapatkan nilai K adalah 1,10 per tahun dan nilai Loo adalah 54,2 mm. Laju kematian total (Z) udang jerbung jantan adalah 2,46 per tahun, laju kematian karena penangkapan (F) dan laju kematian alami (M) masing-masing 1,37 per tahun dan 1,09 per tahun. Untuk udang betina didapatkan nilai Z adalah 1,69 per tahun, nilai F dan nilai M masing-masing 0,61 dan 1,08 per tahun. Laju pengusahaan (E) udang jerbung jantan adalah 0,56 per tahun dan nilai E udang betina adalah 0,36 per tahun. Pola penambahan baru udang jerbung di perairan Cilacap berlansung sepanjang tahun dengan puncaknya pada bulan Maret dan April. Tingkat pemanfaatan udang jerbung jantan sudah berada dalam tahapan overfishing dan perlu dilakukan pengurangan jumlah upaya.High market demand of banana prawn have consequence in fishingactivities which is carried out continuously throughout the year, so that could be threaten of resources sustainability. Scientific advices on the population characteristic are required as an input to support fisheries management. The purpose of the study was to identify population characteristic of the banana prawn with survey method. Study on the population characteristic of banana prawn (P. merguiensis de Man) was conducted in Cilacap and the surrounding waters based on data collected during, January 2013 to November 2013. Result showed that the size at first maturity (Lm) of banana prawn was 38.3 mm in carapace length. The spawning season of banana prawn in Cilacap and the surrounding waters occures throughout the year with the peak in January. The growth parameters of male (K) was 1.0/year with maximum carapace length (L ) of 40.7 mm and K for female was 1.10/year with maximum carapace length of 54,2 mm. Instantaneous total mortality rate (Z) and natural mortality rate (M) of male were 2.46/year and 1.09/year, respectively. While fishing mortality (F) and exploitation rate (E) respectively were 1.37/year and 0.56/year. The total mortality (Z) and natural mortality (M) of female  respectively were 1.69/year and 1.08/year. Fishing mortality (F) and exploitation rate (E) were 0.61/ year and 0.36/year. The recruitment pattern of banana prawn in Cilacap and surrounding waters occures throughout the year with two peaks in March and April. The exploitation rate of male of banana prawn fisheries in Cilacap waters was high. It was, therefore, recommended that fishing effort of the banana prawn in that waters should be reduced in the next year.

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.

No abstract

(P.T. Perikanan Samodra Besar) data are a valuable source, since they are the longest time series of catch and effort data available from the fishery. This paper aimed to interpret the spatial and temporal catch and effort trends to the extent possible and to reconcile apparent changes in targeting practices against the actual catch. Catch and effort data collected by P.T. Perikanan Samodra Besar from its Benoa-based longliners during 1978-1995 were summed to obtain annual catch, effort, and catch per unit of effort trends. To generate spatial distributions of catch and effort, catch and effort data were aggregated by 5-degree squares. The data showed that P.T. Perikanan Samodra Besar vessels commenced deep longlining in 1983, i.e. 56% of the total sets in 1983 using 10 or more hooks between floats. Prior to that, P.T. Perikanan Samodra Besar vessels used 6 hooks between floats,which resulted in a larger amount of yellowfin tuna (Thunnus albacares) as well as overall tuna catch. However, bigeye tuna (Thunnus obsesus) catch per unit of effort only increased from 1992. The increase in big eye tuna catch per unit of effort coincided with a reduced fishing range and concentration within an area where P.T. Perikanan Samodra Besar had not previously experienced high big eye tuna catches, as opposed to focusing their effort on areas where they had historically caught big eye tuna. In the absence of supplementary information, and assuming that the switch to deep longlining in 1983 was done to target big eye tuna, the analysis suggests that the outcome of P.T. Perikanan Samodra Besar fishing activities between 1983 and 1991 were inconsistent with their objectives.