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Pesut Mahakam abundance & threat monitoring survey 2005

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PESUT MAHAKAM CONSERVATION PROGRAM 2005

TECHNICAL REPORT:

Abundance and threats monitoring surveys during medium-high and low waterlevels, June & September 2005

by

YAYASAN KONSERVASI RASI

Sponsored by the Van Tienhoven Foundation

&

The Whale and Dolphin Conservation Society

Primary researcher: Danielle Kreb

Samarinda, December 2005


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Preface and Acknowledgements This technical report presents results of the abundance and threats monitoring surveys on the freshwater Irrawaddy dolphin population in the Mahakam River, in East Kalimantan, Indonesia. This research is part of the larger “ Pesut Mahakam Conservation Program”, which is an ongoing research and conservation program executed by Yayasan Konservasi RASI since 1999 in cooperation with the East Kalimantan Nature Conservation Agency (BKSDA Kaltim) and local Governments (West and Central Kutai Districts). Data were collected at medium-high water levels in June 2005 and low water levels in September 2005. The data within this report are still under revision and should not be cited without prior permission of the author.

Surveys were conducted by Danielle Kreb, Arman, Syahrani and Hari Moelyono. Photo-id analysis was performed by Danielle Kreb, Syahrani and Rafidha Agustina. I would like to thank them and our boatsmen, Masman and Pak Acoh very much for their serious efforts and hard work. I am also grateful for the information that fishermen, villagers along the Mahakam and colleagues shared with me.

I would like to thank the Van Tienhoven Foundation and the Whale and Dolphin Conservation Society for their financial support to conduct these surveys. Samarinda, 29 December 2005,

Daniëlle Kreb (Ph.D.) Scientific Program Advisor/ Primary Researcher Yayasan Konservasi RASI P.O. Box 1105 Jl. Pandan Harum Indah (Erlisa), Blok D, No. 87 Samarinda, Kalimantan Timur Indonesia Tel/ fax: + 62.541.206406/ 081347433450 E-mail: [email protected] / [email protected] http://www.geocities.com/yayasan_konservasi_rasi

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Contents page Preface & acknowledgements . . . . . . . i Summary . . . . . . . . . 1 Introduction . . . . . . . . . 1 - History and background . . . . . 1 - Objectives . . . . . . . . 2 Methods . . . . . . . . . 2 - Data collection . . . . . . . 2 - Analysis . . . . . . . . 3 Results . . . . . . . . . . 4 - Distribution . . . . . . . . 4 - Abundance . . . . . . . . 5 - Group size & composition . . . . . . 5 - Threats . . . . . . . . 5 - Potential and future threats . . . . . . 6 - Current & past conservation activities . . . . 7 - Current & future research plans . . . . . 7 - Conservation action plan . . . . . . 8 Discussion . . . . . . . . . 8 References . . . . . . . . . 9 Financial report . . . . . . . . 11 Figure 1 . . . . . . . . . 4


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Summary Data were collected during medium-high water levels in June 2005 and low water levels in September 2005 in order to monitor the population abundance, importance of earlier identified core areas and threats to the freshwater Irrawaddy dolphin population in the Mahakam River in East Kalimantan, Indonesia. Based on Petersen Mark-Recapture Analysis the population was estimated at 70 individuals (CV=10%; 95% CL = 58-79). Direct counts based on total number of identified dolphins estimated the population in 2005 at 67 individuals. The major threat involved direct mortality, which was largely caused by gillnet entanglement (66% of all deaths). A decrease in minimum annual mortality was detected for years 2000-2005 in comparison to the period of 1995-2000 with average minimum annual mortality of three and six dolphins, respectively. Other threats are habitat degradation through noise and chemical pollution, prey depletion through unsustainable fishing techniques, habitat displacement from container barges and increasingly shallow lakes through sedimentation. Previously identified core areas between 1999 and 2002 maintained their importance, where in the “Muara Pahu core confluence area” dolphins had an average daily occupancy of 48% of daylight hours. Between 36% (22 dolphins) and 43% (26 dolphins) of the total number of 61 identified dolphins in 2005 were observed in this area, whereas in the second largest core area “the Pela/ Semayang –Muara Kaman area” 28% (17 dolphins) of the total identified dolphins was observed. Current conservation activities focus on gaining local (governmental) support to protect these areas through district workshops and through the establishment of a Mahakam Information Center in the Muara Pahu core area. In this area, an alternative fisheries project is initiated to reduce gillnet use and reduce mortality caused by gillnet entanglement. Introduction History and background River dolphins and porpoises are among the world’s most threatened mammal species. The habitat of these animals has been highly modified and degraded by human activities, often resulting in dramatic declines in their abundance and range (Reeves et al. 2000). In Indonesia one representative freshwater dolphin population is known to inhabit the Mahakam River and associated lakes system in East Kalimantan that is the facultative river dolphin species Orcaella brevirostris, commonly and locally referred to as Irrawaddy dolphin and Pesut, respectively. The species is found in shallow, coastal waters of the tropical and subtropical Indo-Pacific and in the following major river systems: Mahakam, Ayeyarwady, Mekong, where alarming declines in their numbers and ranges and ongoing and pervasive threats occurred (Smith et al., 2003). The species is protected in Indonesia and adopted as symbol of East Kalimantan and has been classified as “Critically Endangered” in 2000 based on the results of the ongoing research program (Pesut Mahakam Conservation Program) (Hilton-Taylor 2000). Data were collected during a two-months preliminary study in 1997 and during 3.5 years intensive research from early 1999 until mid 2002 in order to fill in the total absence of knowledge on the freshwater Irrawaddy dolphin population status in the Mahakam River and of coastal Irrawaddy dolphins in East Kalimantan, Indonesia. The research focused in particular on their abundance, population dynamics, threats, and a comparison was made between coastal and freshwater Irrawaddy dolphins regarding their social structures, acoustic behaviours and their degree of separation. Main findings with regards to conservation of the freshwater population involve the supposed separation from the coastal population since at


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least the last glacial maximum, mean minimum annual birth and mortality rates of 11% and 9%, respectively of a total best estimated population of N = 55 (Petersen’s mark-recapture analysis) and a main distribution in a section of ca. 180 km and ca. 375 km from the mouth including lakes and tributaries with a preference for confluence areas. Objectives The aim of the current research project conducted in 2005 was to provide a comparative set of data to detect any trends in abundance, to update the photo-id catalogue, to assess the stability of preferences of core areas, and obtain the latest information on threats and on mortality rates since 2001. Based on this new information, the new course will be set out for conservation action, which effectively will contribute to the population’s survival. This latest information will be presented in a district workshop scheduled in April 2006 related to habitat improvement at district level in one major dolphin core area. Methods Data collection We searched the Mahakam River by boat from Muara Kaman (180km from the coast) to Data Bilang (480km from the coast) including the tributaries Belayan, Kedang Rantau, Kedang Kepala, Kedang Pahu and Ratah, and Semayang Lake based on previous sightings information (Kreb & Budiono, 2005a) and interviews with residents that confirmed their absence in more upstream sections. Two surveys were conducted, one in June 2005 at high-medium water levels and another in September 2005 at low water levels, each lasting 15 and 18 days respectively, including intensive monitoring in two dolphin core areas, i.e. the Muara Pahu confluence area and area between Pela/ Semayang and Muara Kaman and including confluence areas of Belayan, Kedang Kepala and Kedang Rantau. Total distance searched during both surveys was 1319 km. In order to estimate abundance two methods were used, i.e. direct counts and mark-recapture techniques through photo-identification (described in detail in Kreb, 2002 & 2005b). To monitor abundance and locate dolphin groups during both surveys, the river was scanned from small motorized boats (12 hp) traveling at an average speed of 10 km h−1. The observation team consisted of three observers: two front and one rear. The total observation effort of groups of dolphins for both surveys was 36 h. Digital photographs were taken of dolphin dorsal fins using a digital Canon Eos 20D camera and 300mm/f4.0 lens. Effort was made to photograph every individual within the group irrespective of whether they appeared to have distinct dorsal fin markings.

For each sighting, duration, location, group behaviour, size and composition were noted. In addition, land-based observations were made in the confluence area of Muara Pahu (Fig. 1), c. 300 km from the coast, which was frequented daily by various dolphin groups. Three sequential days of land-based observations were made by two observers, who overlooked the area from c. 5 m above the water surface (medium-high waterlevels) for a total of 28 h search time and 13,5 h dolphin observation time. When a group of dolphins was sighted we recorded group size and composition, changes in group composition, and time spent in the area.


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Having already determined the number of dead dolphins between 1995 and 2001 (Kreb, 2005a), we determined the number of dead dolphins between 2002 and 2005 from our observations and from semi-structured interviews with fishermen during the 2005 surveys and also from 230 questionnaire interviews that were conducted in April 2005 that focused on socio-economics and biodiversity as part of the Pesut Mahakam Conservation Program. Incomplete or untrustworthy accounts with missing locality, date, or traceable eyewitnesses were disregarded. Analysis In order to estimate abundance Petersen’s method for mark-recapture analysis was used, which assumes that in between the period of mark and capture there are no gains and losses. During the first survey in June no neonates were observed, whereas in the second survey only one neonate was observed. Since there were no dead dolphins reported between the survey periods, we consider the error very small and the Petersen’s method very suitable. Because of improved technology due to use of digital photography and use of burst photography options we were able to photograph calves’ dorsal fins as well, so a correction factor was left out to account for unidentifiable dolphins, which was used in (Kreb, 2005b). A straightforward formula to estimate abundance and approximate confidence limits of the Petersen method were used as described in (Sutherland, 1996): Eqn 1.1 N = (n1 + 1) (n2 + 1)/ (m2 + 1) – 1

Eqn 1.2 W1, W2 = p±[ 1.96√ p(1-p)( 1-m2/n1)/ ((n2 -1) + 1/2n2] CL1,2 = n1/ W1,2 where: N = total population size n1 = number identified on the first occasion; n2 = total number identified on the second occasion; m2 = number of previously identified dolphins found on the second occasion; p = m2/ n2 CL1,2 = lower and upper approximate confidence limits The matching of photo-identified individuals in the 2005 survey to the existing photo-id catalogue was performed by three analysist in order to obtain an objective match or new id. Direct count estimates were based on the total number identified per survey and both surveys combined (total number of different individuals). Direct counts of one group of six dolphins trapped in the Ratah River were added, which were not photographed but whose presence was confirmed. Since no dolphins were reported dead in between both survey periods, we assumed that all individuals present in the first survey were still alive in the second survey period. In order to measure mean group size per survey, we used the definition that a group would maintain its composition and size for at least one hour. If observation time lasted several hours and other groups were observed to join, the newly formed group was only included if the formation lasted for one hour.


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Results Distribution Sightings during the 2005 surveys were confined to the area between Muara Kaman (c. 180 km from the coast) and Datah Bilang (c. 480 km from the coast) and to the tributaries Kedang Pahu and the confluence of Pela and Semayang Lake. During the first survey in June at high-medium water levels, sightings were confined to two dolphin core areas, “the Muara Pahu area” (c. 300 km from the coast) and “the Pela/ Semayang – Muara Kaman area” (c. 180km from the coast), whereas in between both areas over a distance of 120 km, no dolphins were found in the main river. On the contrary, during the low water levels groups of dolphins were more spread out over the entire length of the main river.

During the three-days land-based observations in Muara Pahu at medium-high water levels, we found that dolphins were daily present on average in the confluence for 48% of daylight hours. Between 12 and 22 dolphins were daily identified and a total of 26 different individuals identified over three consecutive survey days. At similar water levels in the “the Pela/ Semayang – Muara Kaman area”, 17 dolphins were identified during 3 consecutive survey days. At low water levels in the Muara Pahu area each day 12 individuals were identified to visit the area and a total of 22 different individuals over 3 survey days, whereas no dolphins were encountered in the “the Pela/ Semayang – Muara Kaman area”. However, at two locations in between both core areas, groups were identified of 12 and 14 individuals composed of a mixture of individuals, that are usually confined to one core area.

D atah B ilang

Sem ayang

M elin tang

Jem pang

M uara Benangak

M uara Kam an

D am ai

M uara Pahu

Loa Ku lu

Long Bagun

Ko ta B angun

B atuq M uara Je lau

T ep ian U lak

R am bayan

Bohoq

M uyub U lu

Kedang R antau

K edang K epala

B elayan

Kedang Kepa la

R atah

M ahakam D elta

Fig. 1. Study area with a) total dolphin distribution area, b) areas of high dolphin density and c) coastal Irrawaddy dolphin area. The coastal dolphin area is based on observations and interviews. Identified dolphin conservation core areas are marked with two dark gray highlighted circles). Proposed larger protected areas with zonation management for extractive, restrictive and prohibited use of natural resources are indicated by the largest circle encompassing the two smaller areas).

Pela


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Abundance Mark-recapture analyses based on photo-identification gave a total population estimate of 70 dolphins (CV = 10%; CL = 59-79) with Petersen’s method. Direct counts based on photo-identified individuals of both surveys combined (61 different dolphins) including the “Ratah” group (6 dolphins) that was not photographed gave an estimate of 67 dolphins. Dolphins identified and counted during the medium/high and low water level survey were 49 and 52 dolphins, respectively. Average photo-id success rate (total dolphins photographed/ dolphins visually counted) for each group sighting was 91%. Groupsizes & composition Mean group sizes encountered during on-effort sightings were six and ten dolphins respectively during the high-medium and low water-level surveys. During the surveys between 1999 and 2002 mean group sizes were four dolphins for both water levels. Group sizes of six and higher were mostly formed during temporary inter-group interactions (≤ 1hr) in previous surveys, whereas during the present survey large group sizes persisted over hours of observation time. Many surface display behaviours were observed such as breaches, saltos, fluke and fin waves and high arch dives, but no behaviours associated with mating. Also, many feeding and travel activities were observed in large groups. In the first survey two different calves were observed, whereas in the second survey four different calves were observed of which one was a neonate calf and probably born in between both surveys. Threats

Mortality causes (1995-2005)

66%8%

4%

6%

6%

6% 2% 2% gillnet entanglement

deliberately killed

trapped in shallow w ater

boat collision

pre- or neonatal mortality

unknow n

electro-f ishing

hook f ishing

Annual mortality and causes

0

1

2

3

4

5

6

7

8

9

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

Year

Num

ber o

f dea

d do

lphi

ns

hook f ishingelectro-f ishingunknow npre- or neonatal mortalityboat collisiontrapped in shallow w aterdeliberately killedgillnet entanglement

Most dolphins (66%) died as a result of gillnet entanglement with mesh sizes of 10 –17.5 cm. Dolphins were often observed feeding in close proximity to these nets. Dolphins were reported to aid fishermen by guiding fish into their nets. Many fishermen use the dolphins’ feeding patterns as indicators of the location and time to set gillnets thereby increasing the potential for entanglement. Fishermen reported that on several occasions they had successfully released dolphins from gillnets.

The main threat to the population’s survival is direct mortality. Between 1995 and 2005, on the basis of interviews and our own observations, 48 deaths were documented. Mean annual mortality is 4 dolphins per year. Most dead dolphins involved adults (81%), then juveniles (15%) and calves (4%). Regression analysis showed a significant decrease in minimum mortality detected in time (b = -0,41, df = 9, t = -2,15, p = 0.05)


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Five dolphins caught incidentally died in gillnets were eaten and the skin of two of them were used as medicine for skin allergy. Deliberate kills accounted for 9% of the documented deaths, occurring mostly in isolated areas where the dolphins were rarely found. Vessel strikes and pre- or neonatal mortality each caused 6% of deaths and electro-fishing and hook-fishing each caused 2% of deaths.

Besides direct mortality, factors that have degraded dolphin habitat include sedimentation, noise pollution, habitat displacement from container barges, chemical pollution, and prey depletion.

A recent range decline involves the disappearance of the species from Jempang Lake, probably due to a reduction in their depth from excessive sedimentation causes by de-vegetation of surrounding watersheds. High densities of gillnets and sedimentation has also limited movements into the other two lakes, Melintang and Semayang. Dolphins are now, except for high water levels, confined to a narrow boat transport lane between both lakes with danger of collision and noise harassment.

The main source of noise pollution is high-speed vessels (40-200 hp) (mean = 4.6 boats/ h in dolphin habitat), which cause the dolphins to dive significantly longer when the boats are within 300 m distance (Kreb & Rahadi, 2004). Container barges pass daily (mean = 8.4 boats per day) through the Kedang Pahu, a narrow tributary, which is a primary dolphin habitat. These vessels occupy over two-thirds of the width of the river and over half the depth of the tributary during the dry season. Dolphins always changed their direction (if swimming upstream) when they encountered loaded container barges. During low water levels they actively avoided the tributary, whereas the dolphins previously (before presence of container barges) entered the tributary at low water levels as well according to information from local fishermen.

Mercury and cyanide are introduced into the river from leaks in dams that retain wastes from large-scale gold mining operation and from small-scale illegal operations that operate along the river. Coal dust is frequently dumped accidentally into the river and this may have caused occasionally observed changes in the skin pigment of the dolphins in this area.

Prey depletion due to intensive fishing with gillnets, electricity and poison may also be affecting the animals as more energy may be spent on finding prey. Possibly, decreased fish densities may increase dolphin’s attraction to gillnets. Potential future threats Future threats besides ongoing high mortality rates and habitat degradation include prey depletion from unsustainable and illegal fishing techniques (electro-fishing and poison) and possibly inbreeding depression, such as reduction in the survival of offspring during the first year of life, reduced adult survival, fecundity, and/ or success in competition for mates. However, population viability analysis indicated that the extent to which the population is inbred at this stage is still low. Most likely the Mahakam population has flourished from a small founder population, which is able to maintain its genetic diversity, considering the low pod sizes and scattered occurrence of coastal populations of Orcaella brevirostris. Also, it is supposed that before effects of inbreeding depression take place the population will already be at such an unviable size due to demographic stochasticity and a deterministic decline.


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Current and past conservation activities Conservation work started as soon as data on early estimated and preferred dolphin areas became available. In 1999, a first approach in cooperation with East Kalimantan Nature Conservation Agency (Forestry department) involved increasing public awareness on protected status of the dolphins over the entire length of the river through information dissemination to all heads of villages and leaflet distribution. In 2000, a local NGO, Yayasan Konservasi RASI (Conservation Foundation for Rare Aquatic Species of Indonesia) was established with the specific aim to protect the dolphins and their unprotected habitat. Activities so far include awareness campaigns at several layers of society; monitoring; socio-economic and attitude assessment surveys towards dolphin conservation in fishing communities; fishermen workshops to train in safe dolphin releasements and more sustainable fishing techniques; demarcation of important dolphin sites; establishment of patrolling teams to report illegal fishing activities; establishing a Mahakam Information Center (under construction, completed in February 2006) in the dolphin major core area of Muara Pahu to inform local and travelling residents and tourists about the importance of this dolphin site and to gain local (governmental) interest.

Since most residents showed a positive attitude towards dolphin conservation the next steps involve a district workshop to be conducted in 2006 to create a concerned constituency of stakeholders to continue and manage dolphin and habitat protection. One major dolphin area will be proposed first as dolphin conservation area, protected under local district law. Main focus of the workshop will be the strict application of gillnet setting regulations (time, location, mess size) and gradual removal of gillnets in dolphin core areas, boat speed regulations, exclusion of coal container tug boats in primary tributary habitat and ongoing patrol by local villagers for illegal fishing activities. The gradual removal of gillnets will be preceded by an example project of floating fish-breeding cages using highly valuable fish, and fish food not derived from the river as well as lobby for low-interest governmental loans to set up similar floating cages. A second phase would be the total exclusion of gillnets in defined core conservation areas. A final phase may be upgrading the local protected status by national law. Current and future research plans Current and future research includes (1) monitoring threats, mortality rates and population size (using direct counts, modified strip-transect and mark-recapture analysis methods) to detect long-term trends; (2) updating the photo-identification catalogue to identify site fidelity and social ecology with specific reference to breeding; (3) assessing the long-term fidelity to previously identified core habitat areas; 4) Obtaining the latest information on threats (decrease of habitat quality) and on mortality rates. 5) Collecting tissues from recovered carcasses to assess the genetic variation and demographic connectivity between the coastal and riverine populations; and (5) conducting field tests on the efficacy of acoustically reflective gillnets (e.g. coated with barium sulphate) and acoustic deterrent devise (i.e. pingers) at reducing gillnet entanglement. pingers.


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Conservation action plan Conservation plans include establishing protected or core conservation areas in three 10km segments encompassing confluences at: of the (1) Muara Pahu and Kedang Pahu tributaries to Bolowan; (2) the confluence area of Muara Kaman & tributary Kedang Rantau & confluence of Kedang Kepala; (3) the Pela tributary & southern part of Lake Semayang (Fig 1). Measures to manage fisheries in core conservation areas should be implemented in two phases:

Phase one would entail 1) establishing regulations on the type of gill-nets (mesh size of 10 cm) and on where and when that can be set (not directly at the confluence and nowhere in the conservation area at night); 2) encouraging alternative fishing techniques that do not harm dolphins and reduce fish pressure such as floating cages for breeding valuable fish species using fish food and spawnlings not derived from the river. Since initial investment may be too costly for fishermen, it is recommended that the government provides loans at low interest rate; 3) providing alternative employment options for gill-net fishermen, 4) requiring fishermen to attend their nets; 5) compensating fishermen for nets damaged in the process of releasing entangled dolphins alive.

Phase two would include 1) exclude gill-nets altogether after extensive consultations with the fishermen and alternative gears or employment options are provided; 2) Enforcing laws that prohibit destructive fishing techniques (e.g. electric and poison fishing), logging of riparian areas, dumping of toxic contaminants and live-captures of dolphins; (3) Conducting environmental awareness campaigns at both political and community levels; (4) Establishing fishing reserves in spawning locations of the swamp lakes situated adjacent to the proposed core conservation areas; and (5) Encouraging small-scale, well-regulated eco-tourism centered on dolphin watching to increase political and community support for establishing core conservation zones.

Additional management measures should include (1) establishing speed limits for boats; (2) excluding large coal-carrying ships in the narrow Kedang Pahu tributary (alternative transport options include trucking the coals over improved road, and (3) improving habitat in Lake Semayang and the Pela tributary by dredging a channel from the lake to the Mahakam mainstem to avoid collisions with fast-moving vessels in the only current existing channel. Discussion Total population size estimated during the 2005 surveys (N = 70; CV=10%; 95% CL = 58-79) was higher than previous surveys in 2001 that gave an estimate of 55 dolphins (CV = 6%; 95% CL=44-76), but the maximum range was nearly similar. The difference is most likely not caused because of an increase in population size but because of an increased photographic and identification success rate because in the 2005 surveys digital photography was employed, which greatly increased the number of photographs taken in the field and their quality. The number of animals identified has a significant impact on the total estimated population size. Also, the wider confidence limits of the 2001 estimate indicates that the 2005 estimate is more precise with narrower limits. The high photo-id success rate per group sighting may be due to the fact that photographic effort was continued until we were quite


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sure that most dolphins were photographed, but may also be due to the fact that visual group size estimation may possibly be biased to underestimation.

Basically, no changes in their distribution pattern occurred and dolphins still maintained a high daily presence (in terms of occupancy/ daylight hours and numbers) in the main core are of Muara Pahu and the second core area of Pela/ Semayang – Muara Kaman, although the latter area was unoccupied during the low water level survey, which was quite unusual. The absence of dolphins in this second largest dolphin core area, the conspicuously larger group sizes during the low water level survey encountered in between both core areas, and mixed composure of individuals of both core areas, which are normally confined to one specific area, may indicate that groups of dolphins were engaged in socializing events. This was obvious from their intensive surface display behaviours. However, no actual matings were observed but it may be well possible that mating occurred since our observation time for each group was only one to two hours. In previous surveys, matings always occurred in large groups that would finally break up.

The fact that dolphin groups were more spread out over the river length confirms earlier research that indicated that at high water levels (not rising but stable) dolphins have a high daily presence in confluence areas due to the fact that fish abundance is higher then due to the high strength of the counter current, in which the dolphins can easily prey on momentarily trapped fish. At decreased counter current strengths fish can more easily escape and join the main river.

Identified threats remained similar with previous research periods (1999-2002) and the main cause of mortality was still caused by gillnet entanglement. However, during previous reseach, the mortality was estimated at 5 individuals per year (1995-2001), whereas mortality based on 1995-2005 data is lower, i.e. 4 individuals. Regression analysis showed a significant decrease in minimum mortality in time (b = -0,41, df = 9, t = -2,15, p = 0.05). When data is split and minimum mortality from 1995 until 1999, and 2000 until 2005 is analyzed separately, the mean minimum annual mortality for the first period is 6 dolphins and for the second period 3 dolphins. Because dead dolphins are usually not buried, a dead dolphin is easily detected by villagers along the river. It is not likely that mortality or reporting rate has decreased over time. However, calves may possibly be less conspicuous and may explain the low number of detected calf mortality. Two new causes of death has recently added the list of causes, i.e. electro-shock and hook-fishing. Although still sporadic, awareness will be raised to alleviate this problem. References Hilton-Taylor, C., 2000. 2000 IUCN Red List of Threatened Species. IUCN, Gland,

Switzerland and Cambridge, U.K. Kreb, D., 2002. Density and abundance of the Irrawaddy Dolphin, Orcaella brevirostris, in the

Mahakam River of East Kalimantan, Indonesia: A comparison of survey techniques. Raffles Bull. of Zool., Suppl. 85-95.

Kreb, D. and Rahadi, K.D. 2004. Living under an aquatic freeway: effects of boats on Irrawaddy dolphins (Orcaella brevirostris) in a coastal and riverine environment in Indonesia. Aquatic Mammals 30, 363–375.

Kreb, D. and Budiono. 2005a. Conservation management of small core areas: key to survival of a Critically Endangered population of Irrawaddy river dolphins Orcaella brevirostris in


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Indonesia. Oryx 39 (2), 1-11. Kreb, D. 2005b. Abundance of freshwater Irrawaddy dolphins in the Mahakam in East Kalimantan,

Indonesia, based on mark-recapture analysis of photo-identified individuals. Journal of Cetacean Research and Management 6 (3), 269-277.

Reeves, R.R., B.D. Smith, & T. Kasuya, (eds), 2000. Biology and conservation of freshwater cetaceans in Asia. Occasional Paper of the IUCN Species Survival Commission, 23, IUCN, Gland, Switzerland.

Smith, B.D., Beasley, I. & Kreb, D. (2003) Marked declines in populations of Irrawaddy dolphins. Oryx, 37, 401-401.

Sutherland, W.J. (ed) 1996. Ecological Census Techniques. A Handbook. Cambridge University Press, UK. 336pp.


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Financial report, abundance survey 2005

Cost/Unit Total Costs No. Items Unit Total Units Rp. Euro Rp. Euro

I. Preparation

- Return flight Amsterdam_Balikpapan for primary researcher 1 1 15.100.000 1372,73 15.100.000 1.373

- Travel insurance (4 months) 1x4 4 715.000 65,00 2.860.000 260

- Living expenses primary researcher (4 months) 1x4 4 3.300.000 300,00 13.200.000 1.200

II. Survey

-Boat rent for 33 days 1 boat 33 400.000 36,36 13.200.000 1.200

-Consumption for 5 persons 3 times/ day 5x3x35 525 20.000 1,82 10.500.000 955

- Accommodation 5 persons 5x35 175 25.000 2,27 4.375.000 398

- Honor for 3 assistants 36 days (+ bonus, 1 day) 3x36 108 100.000 9,09 10.800.000 982

- Assistants insurance 3x1 3 260.000 23,64 780.000 71

Transport of survey team (4) to study areas(return) = 4 days for 2 surveys 2x2 4 450.000 40,91 1.800.000 164

III. Equipment - Handicam film cassettes 5 pcs 5 80.000 7,27 400.000 36

- Batteries 4

boxes 4 100.000 9,09 400.000 36 - Laptop reparation 1 1 1.250.000 113,64 1.250.000 114 - Handicam reparation 1 1 1.000.000 90,91 1.000.000 91 IV. Report Final Report 10 exp 10 25.000 2,27 250.000 23

V. Contribution to support RASI office costs

-Office use (4 months) 4

months 4 500.000 45,45 2.000.000 182

- Honor 1 staff member involved in research preparation, analyzing (2 months) 1x2 2 1.500.000 136,36 3.000.000 273

VI.

Carcass (1) and sample retrieval (3) of three dead dolphins (incl. transport RASI staff & BKSDA official) 1 3 1.150.000 104,55 3.450.000 314

Total expenses 65.815.000 7.670 Contribution WDCS 1.500 Contribution Van Tienhoven Foundation 6.126 Total received 7.626

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