HCNSO Student Theses and Dissertations

Defense Date


Document Type


Degree Name

M.S. Marine Biology

First Advisor

Bernhard Riegl

Second Advisor

David Kerstetter

Third Advisor

Lemnuel Aragones


Whale-watching provides economic opportunities worldwide and particularly proliferates in developing countries, such as the Philippines. The sustainability of whale-watching is increasingly debated as these activities also negatively impact cetaceans through changes in behavior, communication, habitat use, morbidity, mortality, and life-history parameters. This study evaluated the total annual cost, revenue, and profit of whale-watching operators in Bais, Philippines, and predicted the changes in the population for spinner dolphin Stenella longirostris with varying levels of whale-watching effort. Total revenue was 3,805,077 PHP ($92,478 USD) while total cost was 5,649,094 PHP ($137,294 USD) with a discount rate of ten percent. The total annual profit of whale-watching in Bais was – 1,844,017 PHP (– $44,817 USD). On average, each operator in Bais lost 160,350 PHP ($3,897 USD) per year from whale-watching. Through time, the spinner dolphin population decreased as it was exposed to more vessels, causing effort to increase, and thus decreased profit for operators. Under current whale-watching effort, the spinner dolphin population was predicted to decrease by 94 percent in 25 years. If Bais reduced effort in their operations to only three vessels whale-watching per day, the spinner dolphin population increased to 80 percent of its initial population size. This was the first study to predict the spinner dolphin population and estimate the total annual profit from whale-watching in Bais, Philippines. It provided data to locals for efficient, profitable, and sustainable decisions in whale-watching operations.

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