MODEL PENDUGAAN PRODUKTIVITAS PERIKANAN PUKAT CINCIN DI LAUT JAWA

Produktivitas perikanan dipengaruhi banyak faktor, salah satu faktor adalah upaya dan lingkungan yang meliputi suhu permukaan laut (SPL), ketinggian permukaan laut (KPL), klorofil-a, angin, arus, SOI, DMI dan curah hujan. Faktor-faktor tersebut terlebih dahulu diuji multikolinearitas kemudian dianalisis komponen utama untuk mereduksi faktor. Selanjutnya faktor terpilih menjadi masukan bagi jaringan syaraf tiruan (JST) dengan bantuan Forecaster XL. Data yang digunakan merupakan data runtun waktu bulanan selama 16 tahun (1996 - 2011) untuk menyusun model pendugaan dan memvalidasi produktivitas pukat cincin pada tahun 2011. Hasil analisis menunjukkan 9 faktor yang diduga berpengaruh bersifat saling bebas, dan kemudian disederhanakan menjadi 4 faktor dengan PCA. Hasil training data dengan JST diperoleh koefisien pendugaan produktivitas terbaik, dengan nilai korelasi (r) dan Root Mean Square Error (RMSE) berturut-turut sebesar 78.03% dan 48.93%. Fisheries productivity are effected by many factor, such as effort and environment factors; including SST, SSH, chlorophyll-a, wind, current, SOI, DMI and rainfall. That factors are tested by multicolinearity analysis and principle component analysis (PCA) first, to reduce factors. Furthermore, simplified factors will entered to Forcaster XL for artificial neural network (ANN) analysis. This analysis was used monthly time series for 16 years (1996-2011), as a prediction target is purse seine productivity in 2011 and will validated by actual values. Results show that 9 factors were independently (no multicolinearity), furthermore that factors was simplified to 4 factors using PCA. ANN training resulted the best fit coefficient to predict productivity which have correlation value (r) and Root Mean Square Error (RMSE) 78.03% and 48.93% respectively

A Rapid Assessment of the Marine Megafauna Biodiversity Around South Bali, Indonesia

A low-cost, small-boat, rapid assessment survey was conducted on the waters off the southern Peninsula of Bali. The objectives were: (1) to conduct an inventory of cetacean species in the study area; (2) to map cetacean distribution to inform the design of the Badung MPA; (3) to estimate relative abundance of cetaceans and record information on presence and distribution of other marine megafauna; and (4) to train observers in the use of distance sampling methods. The survey adopted a “training while doing” approach to build local capacity for marine biodiversity monitoring, while collecting a snapshot of data to assess species richness and distribution. The survey accomplished its first two objectives, but due to violation of underlying assumptions, had mixed success with the third objective. Our survey revealed that the waters off the southern Peninsula of Bali support a rich cetacean fauna, with at least seven cetacean species, other marine megafauna, and avian species. Seven cetacean species found on our survey include: spinner dolphin (Stenella longirostris), pantropical spotted dolphin (Stenella attenuata), Fraser’s dolphin (Lagenodephis hosei), Risso’s dolphin (Grampus griseus), bottlenose dolphin (Tursiops sp.), Bryde’s whale (Balaenoptera edeni), and sperm whale (Physeter macrocephalus). Density estimates were low for all whales combined, but seem implausibly high for dolphins; likely due to violation of assumptions of distance sampling methods. Future surveys should include sufficient time for training to generate reliable abundance estimates. A dedicated bycatch study is needed to understand sustainability of bycatch mortality relative to reliable abundance estimates

Mangrove monitoring for mangrove conservation and adaptive management

Mangroves are important ecosystems that provide a huge range of benefits for coastal communities. The management of mangroves requires multiple methods and approaches that contribute to answering the policy relevant questions. Our site is in the Perancak estuary, Bali, where mangroves were degrading in 1980's due to the conversion of mangrove forests to aquaculture ponds and later reestablished in early 2000 when many aquaculture ponds were abandoned due to economic crisis and the diseases. Monitoring of mangroves in this area has been conducted since 2004, aiming to identify the ecological processes in mangrove ecosystems that support mangrove conservation initiatives and coastal management. The study showed the recovery in net primary productivity (NPP) and carbon sequestration capacity of mangroves in abandoned ponds. Our results support the view that mangroves are highly productive ecosystems that can recover from disturbances even from extensive land conversion through destruction of mangrove trees, and undertake reshaping of hydro-biogeochemical processes. Mangrove extent can grow by self-regeneration and replantation throughout the 7.5 km² estuary, this resulting in the reverse process of aquaculture site conversion into mangroves areas. In the frame of the INDESO project (Infrastructure Development for Space Oceanography) mangrove changes in this region are monitored in support of a series of very high resolution satellite images acquired since 2001. The analysis of these data supports the definition of keystone regions for monitoring biodiversity recovery and ecosystem protection. Our goal is to provide recommendations for sustainable management of mangrove coasts that are understandable to local government and stakeholders, including the recommendation that supports the establishment of Regional Marine Conservation Area (or Kawasan Konservasi Laut Daerah, KKLD) of the Perancak estuary. (Résumé d'auteur