How do you count Singapore's wild otters?

Key Concepts

• Otter Census: Systematic surveys to track otter populations in Singapore.
• Changi Bayoin Family: A specific otter family that was particularly difficult to locate during the census.
• Home Range: The area regularly used by an otter family for foraging, resting, and breeding.
• Individual Otter Identification: Distinguishing otters based on unique physical characteristics (markings, chipped teeth).
• Otter Spraint: Otter feces, used to confirm presence and identify diet.
• Bioindicator Species: Otters serve as indicators of environmental health, specifically water quality.

Otter Population Monitoring and the Return of a Species

The video details the efforts to monitor and census the growing otter population in Singapore, highlighting the challenges and rewards of this work. The return of otters to Singapore after decades of absence is presented as a positive sign of environmental recovery, directly linked to improvements in water quality. Otters had disappeared from Singapore in the 1960s and 70s due to heavily polluted waterways. Their reappearance is described as “a story of hope,” demonstrating the positive impact of environmental cleanup.

The Census Process & Data Collection

The first otter census was initiated in 2017 to establish a baseline understanding of the otter population – their distribution, habitat use, and potential challenges related to a growing population. Subsequent censuses were conducted in 2021 and 2024. The census process is described as “rigorous,” emphasizing the need to avoid double-counting individuals and families. This is achieved through careful observation and identification of individual otters.

A key methodology involves long-term observation, building a “pool of knowledge” within a community of “auto watchers” (otter enthusiasts). Observers focus on identifying minute differences in individual otters, such as unique markings on their bodies or physical characteristics like chipped teeth. These details are crucial for accurately tracking families over time.

Locating Elusive Families: The Changi Bayoin Case Study

A particularly memorable experience involved locating the Changi Bayoin family, which proved exceptionally difficult to find. Despite multiple attempts by other observers during the first month of the census, the family remained elusive. The speaker recounts successfully spotting the family after patiently waiting near Changi Bay, noting a “strong smell of spring in the air” as a positive indicator. After 10 minutes of observation through binoculars, the family emerged and was filmed traveling single file to the sea. The speaker emphasizes the significance of this sighting, stating, “without my sight I think this family might not have been included in centers at all. So we’ll be 13 short.” This highlights the importance of dedicated observation in comprehensive census efforts.

Identifying Otter Presence: Utilizing Spraint Analysis

The video demonstrates a practical method for confirming otter presence even when the animals themselves are not directly observed: analyzing their spraint (feces). The speaker explains that otters have “favorite resting places” and that examining these areas for spraint can indicate recent activity. Spraint appears as black, jelly-like material when fresh, containing visible fish scales. As it dries, it becomes white and may reveal chewed fish bones up to 1 cm in length. The speaker cautions against approaching spraint too closely.

Otter Behavior and Habitat Use

Otters are observed to be moving inland from the coast, a phenomenon that is “quite new” to researchers. Observers typically begin searching in familiar areas like Marina Bay and the Singapore River, but during the census, they make a “concerted effort” to cover less-visited areas such as the northeast (Sembawang), Jurong, and Changi Beach. This targeted approach ensures broader coverage and a more accurate population assessment.

The Significance of Otter Return

The return of otters to Singapore is presented as a direct result of improved water quality and a cleaner environment. As stated, it’s “a testimony to the clean conditions of the waterways.” This positions otters as a valuable “bioindicator species,” reflecting the overall health of the ecosystem.