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Research Report

A First Look at the Fish Species of the Middle Malinau: Taxonomy, ecology, vulnerability and importance

Ike Rachmatika
Robert Nasi
Douglas Sheil
Meilinda Wan
Copyright Date: Jan. 1, 2005
Pages: 42
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Table of Contents

  1. (pp. 1-1)

    Logging, agriculture, and activities like road construction have led to increased sedimentation, siltation, and decreasing water quality in numerous rivers around the world (Alabaster & Lloyd 1981; Rivier & Seguier 1985; Scarbovick 1993; Moring et al. 1995). This is obviously of some concern when considering the status of fish populations, since increased suspended sediment can adhere to gill tissue and lead to respiration difficulties, with subsequent gill abrasion leading to pathogenic penetration. Suspended sediments also decrease phytoplankton, attached algae, and rooted aquatic vegetation. In addition, settled sediment may impair reproduction by inhibiting egg respiration and increasing incubation periods. Finally, according to Moring...

  2. (pp. 2-3)

    The focal area of this research is located in the Indonesian province of East Kalimantan on the island of Borneo. The lowland rainforests on the island of Borneo are globally important for their high species richness and endemism (MacKinnon et al. 1996). The Malinau region is part of the last relatively intact contiguous large scale forest cover in Borneo.

    When CIFOR was established in 1993, the Indonesian Government committed itself to providing a forest area where CIFOR could conduct long-term research. An area in East Kalimantan was finally selected and named Malinau Research Forest (previously Bulungan Research Forest). The area...

  3. (pp. 4-4)

    A total of 22 people from three villages (Seturan, Langap and Loreh) were interviewed in order to ascertain indigenous knowledge of freshwater fish. These interviews were conducted using participatory methods, which involved showing photographs of 45 fish species and asking interviewees to rank fish species according to which were the most abundant in their catches, most abundant in their diet and which were the most preferred food species. The interviewees were also asked to list the local medicinal uses of each fish. These scoring approaches drew on parallel surveys simultaneously being applied for terrestrial resources in CIFOR’s more vegetation oriented...

  4. (pp. 5-14)

    The water velocity in the sampling localities varied from slow to fast. The average dissolved oxygen content ranged from 6.30 to 8.34 mg/L, average pH ranged from 6.81 to 7.09 and average water temperature ranged from 25.26 to 27.30º C (see Table 1a & b).

    Over the course of the two-year survey, there were seven (unaveraged) records of sites with low oxygen levels, ranging from 1.97 to 3.58 mg/L. Such low dissolved oxygen content might be a limiting factor for fish life. According to Sylvester (1958) and NTAC (1968) in Wardoyo (1978), a dissolved oxygen content of 4 mg/L is the...

  5. (pp. 15-15)

    Seturan water catchment has high fish diversity (contained 47 fish species, 32 genera, 13 families and 3 orders) where these fishes are important to local people as food items, for sale and other purposes.

    Local knowledge is clearly underlined by the fact that virtually all species recorded are known and distinguished by local informants.

    Some species are vulnerable to local land-use changes (mainly sedimentation).

    Properly planned logging activities and good fisheries appear possible at the same time....