Recent updates on otter researches in Indonesia

Presented in Kawauso Koza 10 September 2017, Inokashira Park Zoo, Tokyo, Japan. This event was organized by Kawauso Friends
Presentation slide is available in Figshare https://doi.org/10.6084/m9.figshare.5518951.v1
In this lecture, I presented recent updates on otter researches in Indonesia. The presentation were divided into three parts.
Part 1. Ecology of small-clawed otter in rice field landscape

  • Tracks and signs of otter in rice field (Aadrean et al 2010)
  • Diet composition of small-clawed otter in rice field (Aadrean et al 2011; unpublished data)
  • Latrine site use of small-clawed otter (Aadrean and Usio, submitted to Ecological Research)
  • Sprainting behaviour of small-clawed otter from camera trap data (unpublished data)

Part 2. Human and otters in West Sumatra, Indonesia

  • Otters in local social culture of West Sumatran people (Aadrean and Yunis 2015)
  • Conflict of otter with fish farmer (unpublished data)
  • Conservation project: otter friendly fish-farming

Part 3. Otters on Indonesian cyberspace

  • Otter trading as pet in online market (Aadrean, 2013)
  • Compiled record of hairy-nosed otter from communities on internet (Lubis and Aadrean, Unpublished)
  • Projects: website http://berang-berang.com; citizen science for otters in Indonesia

 

References:

Part 1. Ecology of small-clawed otter in rice field landscape

The small-clawed otter (Aonyx cinereus) is distributed in South and Southeast Asia, and has been designated a vulnerable species by the International Union for Conservation of Nature (IUCN). Small-clawed otters are carnivores that primarily prey on aquatic animals, such as crabs, fish, frogs, arthropods, mammals, and snails. Small-clawed otters use a variety of natural and human-altered habitats, including rivers, streams, peat swamps, mangrove forests, rice fields, ditches, and fish ponds. Although small-clawed otters are common in zoos, their basic ecology is largely unknown in the wild. Small-clawed otters are inhabits rice field in Malaysia, Thailand, the Philippines, and Indonesia. This species use rice fields as foraging and latrine sites.

In Indonesia, we performed ecological studies on small clawed otters in rice fields landscape. The study site was located in rice field landscapes along the Batang Anai River drainage in the Padang Pariaman Regency, West Sumatra. The Padang Pariaman Regency has tropical climate. In our study sites, rice fields are planted 2–3 times a year. Farmers can start a new planting cycle any time of year at their discretion. Consequently, different planting phases can be found across the entire landscape throughout the year.

The first study was initiated in 2008. First, we identified which otter species inhabit in the study sites, using otter foot-prints in rice field mud. We described characteristic footprints, latrine sites, sliding sites and other signs. We recorded also the damage to vegetation of levees and the rice plants adjacent to latrine sites. In this study we recorded 13 latrine-sites.

In 2010, we studied composition diet of the small-clawed otters. We collect scat samples from latrine sites that found since 2008. In addition, we found 14 new latrine sites. We found that small-clawed otters consume fishes, golden-apple snail, water insect, frogs, and crabs. Dominant food are fishes. This finding differ than previous study that the dominant food of small-clawed otters were crabs. Interestingly, we found golden-apple snails, the pest invasive species, as second dominant food of this species. This is the first evidence of small-clawed otters foraging on this invasive pest species. In this survey we recorded additional 13 latrine sites. Total 40 latrine sites have been recorded in the study site.

In 2015 to 2016, we tried to reveal ecological factors important for latrine-site. Using a year weekly-surveys and ecological modeling (GLM or GLMM), we described important factors of landscape and local environment for (1) occurrence of the latrine sites (2) frequency of small-clawed otter visitations to the latrine sites (3) temporal factors of small-clawed otter visitations. We found that intermediate number of rice field huts was the single most important predictor of latrine site occurrence, whereas distance to the nearest settlement, distance to the river, and mean water depth of the rice field adjacent to the latrine site were important predictors of otter visitation frequency to latrine sites. For temporal aspect, latrine sites that were adjacent to vegetative stage of rice fields with abundant golden-apple snails (Pomacea canaliculata), a food item for otters, experienced the highest probability to be visited by small-clawed otters.

We also recorded sprainting behaviour of small-clawed otter. We used camera trap to record activity of small-clawed otter in their latrine site in rice field landscape. We put camera trap in three latrine sites from July 2016 to June 2017. We selected the three latrine sites, because the latrine sites were the most visited latrines based on a year weekly monitoring. After rapid check to thousands images and videos, we found up to 10 individuals recorded in one frame of image of video. The otters mostly visited latrine sites in night time (nocturnal). We recorded scent marking activities, such as “sprainting dance” and rubbing their body on coconut trees. We recorded also occurrence of new juveniles. We also got pictures and videos of farmers and other animals.

In 2016, we also performed a study to reveal home range of small-clawed otter using telemetry method. Unfortunately, we could not successfully record movement of small-clawed otter. Based on this result, we could not measure home range and territory of the animal.

 

Part 2. Human and otters in West Sumatra, Indonesia

 

Otters have relationship with human. The relationship include positive and/or negative relationship. We studied relationship between otters and West Sumatran people. Most of West Sumatran people regarded the otters as pest for fish ponds. Because the negative impacts, West Sumatran people use the term “kuciang aie” (otters in local language) to attribute someone that has bad behaviors. There are several myths related to otters. The otters were known as having “a magical stone”. If some one has the stone, he/she will have a great capabilities on swimming, like otters. Another myth, If someone’s rice field were broken by otters, it means that the farmer have conducted some negative acts. Unlike in other areas, West Sumatran people did not use otters’ body part. There was no use of otters’ body parts.

In 2015, we distributed questionnaires to groups of fish farmers in Padang Pariaman Regency, West Sumatra. The groups are supervised by field staffs from fisheries department of Padang Pariaman Regency. We requested the field staffs to distribute our questionnaire when they visit the groups. Among approximately 100 groups of fish farmers, we got only 52 groups returned the questionnaire. We questioned fish farmers on their knowledge on otter species. We wanted to know their perception on otters. We also asked their willingness to do otter-friendly fish farming system. Based on our questionnaire, we found that 63.46% of group’s fish ponds have been visited by otters. Otters came to the fish ponds from afternoon to early morning. Most visited-time was in midnight. Interestingly, fish farmers said that 68.42% of the case, otters visitation to fishponds are related to rain condition. Fish farmers believe that number of otter visitation to their fish pond was increased. However, we thought that fish farmers overestimated the conflict. Because only 18.18% of visited-fishponds have been visited by otters recently (in 1 month ago).

To educate the fish farmers, we manage a short lecture in hall of fishery department in 10 September 2016. The short lecture was attended by fish farmers and field staffs of fishery department. We explained biology of otters in Indonesia, particularly on small-clawed otter. We also explained what we have done for research and conservation activities. We invited the participant to gain more positive respect to otters. In the afternoon, we conducted Focus Group Discussion (FGD) among fish farmers. We collected all of available methods on how to protect fish ponds from otter. Then, we determined the best way on how to protect fish pond from otters. We gave score to each method in three aspects; effectivity, money efficiency, and otter safety. We recorded various methods, from scientifically-sound methods to myth-like methods. Based on the FGD, we determined the following methods as the best methods:

1. for large scale or intensive fish ponds

  • create wall surrounding fish pond areas. The wall prevents the theft from human as well

2. for small scale business

  • provide light
  • guard dog protection
  • keep water depth more than 60cm

3. For traditional family fishponds

  • put twigs and branches of bamboo inside the pond. Otters will find it difficult to catch fish

Based on the best methods, then we designed a leaflet on how to protect fish ponds from small-clawed otters. There are two version of this leaflet; Bahasa version and English version. For Bahasa version, we printed and distributed them to fishery department and fish farmers.

In addition, we also shared both version as online version in in website http://berang-berang.com and its Facebook page http://www.facebook.com/infoberangberang and Facebook page of Supportive Environments for the Region’s Otters (SERO). http://www.facebook.com/seroberangberang.

 

Part 3. Otters on Indonesian cyberspace

 

Development of information technology leads the improvement of trading system that use online market system and social media. Online market website is growing in quantity and quality. It offers free to sell all goods of registered member. However, as a result, the online market is also facilitating the illegal trade in wildlife, making it one of the major wildlife conservation challenges.

We investigated otters trading as pet in Indonesian online markets from January to May 2012. Two species of otter (Aonyx cinerea and Lutrogale perspicillata) were sold in the online market. All of trading were recognized from Java island with East Java Province as the biggest trade activity. Price varied from 150,000 to 800,000 IDR (average 430,186 IDR, approximately 4,000 JPY) for one-week new born baby to five month juvenile cubs. There were two delivery mechanisms; 1) meet and pay, the seller and buyer make an appointment to meet in particular place, 2) send by cargo after the money have been transfered.

From July 2012 to September 2013, we investigated occurrence of hairy-nosed otter on internet. Hairy-nosed otter is protected by Indonesia laws. We got total six records. Four hairy-nosed otter cubs were kept by people. One adult was photographed in the wild. Another adult was found died near a settlement. The one cub was recorded from Sumatra Island, and the other five individuals were recorded from Kalimantan (Borneo Island). We have tried to confiscate two cubs, unfortunately both died.

In the beginning of 2017, we established a new website http://berang-berang.com. Mission of the website is to be a most complete information resource for otter in Indonesia. We are also conducting a project using citizen science to gather information of otters in all of Indonesia regions.

 

Follow up questions after the presentation

 

I received these questions through email.

 

Q: Are you studying about nests of Otter ?
A: We have tried to find the nest using telemetry. However, we don’t know the nest location yet.

 

Q: Is the nest near the rice fields ?
A: I don’t know yet.

 

Q: Do you know where Otter are resting during the day ?
A: I don’t know yet.

 

Q: Are there riverside of the Batang Anai River ?
A: Yes. There are riversides.

 

Q: Is there damage such as drawing out rice or cutting it ?
A: Usually the damage shows as effect of the otter press or rub on the rice, not draw or cut. See Aadrean et al 2010. Actually the rice can grow and stand again, although the growth is not good.

 

Q: Are golden-apple snails West Sumatra native species ?
A: No, golden-apple snails is invasive species.

 

Q: What is the average depth of rice fields close to the latrine site ?
A: It depends on the growing stage. If watered in vegetative stage, water depth usually 10 cm or less. In pre and post harvesting, rice fields are usually dry.

 

Q: Do Otter contact with people during the day ?
A: No, otter usually come to rice field in night.

 

Q: Due to the recent increase in golden-apple snails, has Otter frequently come to catch food in rice fields ?
A: I can not make sure whether the golden-apple snail is a healthy food for otters or not. In natural wetland, the small clawed otter forage on crab.  There is another hypothesis that small-clawed otter forage on snails because the native food are becoming scarce. However, based on my research on latrine site visitation for more than seven years, the visitations were relatively stable. The small-clawed otter may be an opportunist animal.

 

Q: Originally did Otter use rice fields ?
A: I do not know the exact history. Rice farming have been practiced long time ago in Sumatra. Because rice field is a wetland and a habitat for prey species, I believe otter already use the rice field long time ago.

 

Q: Are people thinking that magical stone exists in all four species in Indonesia ?
A: Most of people are thinking only one or two (smaller and bigger) otter species exist. So, they do not differentiate which species has the magical stone.

 

Q: Are fish farmers actually implementing the best method ?
A: Some of the best methods are already known and implemented by old and experienced farmers.

 

Q: Are there many fish farmers trying to implement the best method ?
A: We do not assess the implementation yet.

 

Q: Are there any compensation from the country or the Padang Pariaman Regency ?
A: No, there is not.

 

Q: Can you deduce the total amount of otter meal from the feces collected?
A: No, I can not. We can only estimate relative proportion of one prey item compare to other items.

 

Q: Have you ever witnessed the corpses of otter during the course of the investigation?
A: No, I have not.

 

Q: Specifically, how do you capture otter to wear a transmitter in the telemetry method?
A: Initially we used log-held trap. Then we changed to use box trap.

 

Q: Do you use anesthesia?
A: Yes, our veterinarian used Atropin, Zolatil and Isoflurane.

 

Q: Does  “… Unfortunately, we could not successfully record movement of small-clawed otter. …” mean you lost sight of the individual with the transmitter?
A: Yes, the individual was lost with transmitter inside its body. After two days, we could not detect any signal emitted from the transmitter.

 

Q: Can you deduce the total amount of otter meal from the feces collected?
A: No, I can not. We can only estimate relative proportion of one prey item compare to other items.

 

Q: Have you ever witnessed the corpses of otter during the course of the investigation?
A: No, I have not.

 

Q: Specifically, how do you capture otter to wear a transmitter in the telemetry method?
A: Initially we used log-held trap. Then we changed to use box trap.

 

Q: Do you use anesthesia?
A: Yes, our veterinarian used Atropin, Zolatil and Isoflurane.

 

Q: Does “… Unfortunately, we could not successfully record movement of small-clawed otter. …” mean you lost sight of the individual with the transmitter?
A: Yes, the individual was lost with transmitter inside its body. After two days, we could not detect any signal emitted from the transmitter.

 

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