Marudu Bay
Location:
6°30'-7°00'N, 116°46'-117°07'E; at the northernmost point of Sabah.
Area:
c.150,000 ha.
Altitude:
Sea level.
Biogeographical Province:
4.25.12.
Wetland type:
01, 04, 05, 06 & 07.
Description of site:
A large sea bay facing northeast, fringed by sandy beaches, mangrove swamps and extensive intertidal mudflats. The most extensive mangroves are situated at the head of the bay (Kudat and Marudu Bay Forest Reserve) and on either side near the mouth (e.g. at Sungei Tenga). Rocky shores characterize the exposed mouth of the bay north of Kudat. The main source of fresh water is run-off from the northern end of the Crocker Range. The mean tidal range at Kudat is 1 .3m. The saline and brackish swamps are permanent; the freshwater areas partially dry out in February-September. One of the most important areas in the bay, the Sungei Tenga mangroves and freshwater swamps, is described separately below (site lla).
Climatic conditions:
Humid tropical climate with an average annual rainfall of about 2,870 mm. There is a distinct peak in the rainfall between mid November and mid February, and a low from March to September, the lowest rainfall occurring in April. The temperatures are probably similar to those at Kota Kinabalu, which has an average maximum temperature of 30.5°C and an average minimum of 23.2°C in open swamps near the coast. Evaporation may exceed precipitation during the greater part of the year.
Principal vegetation:
Extensive mangrove forests with a large component of Rhizophora species. At Sungei Tenga, mangroves commonly associated with the Rhizophora include species of Ceriops, Lumnitzera, Bruguiera and Xylocarpus. The fresh water swamps probably hold large amounts of Baeckia frutescens, Tristania clemenhis and Rhodamnia sp, with many rushes such as Fimbristylis spp. Around Sungei Tenga, large areas of associated transitional forest may contain many Oncosperma palms mixed with relic tall forest trees such as Intsia spp and some coastal dipterocarps such as Shorea glaucescens.
Land tenure:
Much of the wetland is state owned; surrounding areas are largely alienated for permanent and shifting agriculture.
Conservation measures taken:
Some 13,636 ha of forest are included in the Kudat and Marudu Bay Forest Reserve (Class V).
Conservation measures proposed:
At a meeting in 1975 of officials from the Forestry and Fisheries Department, the Land Capability Classification Project and the Lands and Surveys Department, it was suggested that six areas of mangroves in Sabah including Marudu Bay (51,170 ha) be designated as conservation areas in which no large-scale exploitation would be allowed except for traditional uses. It has also been suggested that more areas of fresh water swamp be included within the existing forest reserve at Sungei Tenga. Further survey work is required in order to evaluate the flora and fauna of the area with a view to protection of suitable sites. This applies to waterbirds in particular.
Land use:
Fishing for fin fish and prawns; agriculture and coconut plantations on the Kudat Peninsula. There is an important fish market at Kudat.
Possible Changes in Land use:
No information.
Disturbances and threats:
Reclamation of swamps and clear-felling of mangroves for agricultural land, and probably some hunting.
Economic and social values:
The mangrove swamps and intertidal mudflats support a major commercial fishery for both fin fish and prawns. The catch of prawns in Marudu Bay in 1973 was 77.6 tons, valued at M$283,600.
Fauna:
An important breeding area and nursery ground for demersal and pelagic fish and prawns. The bay is particularly important for carangid and clupeid fishes and mullets, notably Valamugil cunnesius, Liza subviridis, L. vaigiensis and L. tade. The mullets occur mainly in the estuaries of the Kudat Peninsula and the southern part of the bay. Marine prawns caught in Marudu Bay and the Kudat area include Penaeus merguiensis, P. indicus, P. monodon, P. semisulcatus and Metapenaeus ensis.
Marudu Bay is probably also an important area for resident and migratory waterfowl; an aerial survey in February 1985 revealed over 100 ducks (Anas sp) and several hundred shorebirds on the intertidal mudflats.
Special floral values:
None known.
Research and facilities:
Chua and Matthias (1978) have worked on the fishes and prawns of the bay, and have studied the littoral fauna and flora at a study site on rocky shore north of Kudat.
References:
Chua & Matthias (1978); Davies & Payne (1982).
Criteria for Inclusion:
1b, 1e, 2c.
Source:
C. Phillipps.