Aquatic food production in the coastal zone: data-based perceptions on the trade-off between mariculture and fisheries production of the Mahakam Delta and estuary, East Kalimantan, Indonesia.

Abstract

In less than two decades, from 45000 to 70000 ha, or up to 70%, of the mangroves in the Mahakam Delta, East Kalimantan, were converted to shrimp ponds. This is expected to affect the productive and buffering function of intact mangroves, observable as shifts in composition and a possible reduction in productivity of the coastal fisheries. The trade-off between mariculture and fisheries is explored with data from fisheries statistics, surveys and reported information. Analysis of trends and developments in total catch, catch by species category, catch rate, fishing effort, pond production and productivity gave no direct quantitative evidence of reduced coastal production and productivity. Shrimp-pond productivity (125 kg/ha/year) is low, stable and highly variable (CV=69%) at the aggregated level of the delta. Since 1989, fishing efforts have increased and patterns diversified, but aggregated catch rates did not decrease. Catches of rays and sharks decreased and the pelagic/demersal catch ratio increased. A shift towards more resilient species categories with a high turnover rate took place from 1993 to 1999, 4 to 10 years after the boom in pond construction. However, these clear shifts are not self-evidently related to mangrove conversion. Reasons for this are discussed. The potential for detection of changes in resource outcome and assessment of the trade-off between mariculture and fisheries, at both the local level and through aggregated fisheries statistics, is limited because of the high variability in outcome. This implies a limited capacity for resolution of resource-use conflicts when evaluating competing claims informed by existing data and information on resource change.

Estimasi Nilai Eksternalitas Konversi Hutan Mangrove Menjadi Pertambakan Di Delta Mahakam Kabupaten Kutai Kartanegara

“…Pada tahun 2001, 75% hutan mangrove telah dikonversi menjadi tambak (Zwieten et al, 2006). Bengen (2006) menyatakan bahwa dalam kurun waktu 20 tahun telah terjadi konversi mangrove sekitar 80.000 hektar, diantaranya sekitar 67.000 hektar dijadikan untuk tambak.…”

Geostatistical Approach for Site Suitability Mapping of Degraded Mangrove Forest in the Mahakam Delta, Indonesia

“…In 2001, 75% of the delta had been changed to ponds [4], which subsequently reduced to 52% in 2007, as reported by the Fishery and Oceanic Affairs Office of the Kutai Kartanegara District government [5]. Almost 90% of the Mahakam delta region belongs to the Indonesian Ministry of Forestry and is classified to be a production forest, however three other different government sectors lay claim to the management of the Mahakam delta: the Fishery Department, Interior Affairs Department, and the Environment Department [3].…”

The integration of biodiversity conservation with oil and gas exploration in sensitive tropical environments

“…The Mahakam delta was initially covered by a dense mangrove vegetation but, in recent years, shrimp pond development has spread over more than 70% of the delta area with consequent major loss of mangrove habitat ( Fig. 1) (Suripno et al 2004;Van Zwieten et al 2006). Aquaculture activities have also resulted in an increasing number of people working and/or living in the area.…”

“…The rapid destruction of mangrove vegetation peaked in 1997 when the East Asian economic crisis hit Indonesia. As a result, more than 73% of mangrove has been converted into shrimp ponds to date (Van Zwieten et al 2006). Pond areas range from less than 2 ha to up to 50 ha, the average shrimp pond size being about 10 ha (Bourgeois et al 2002).…”