Developmental Changes in the Morphology of Western North Pacific Bryde’s Whales (<i>Balaenoptera edeni</i>)

Developmental changes in the body proportions of western North Pacific Bryde’s whales (Balaenoptera edeni) were investigated by examining the proportion of each body part to the total body length. The head and chest region increased to a certain body length;subsequently, the length of head region stabilized, and that of the chest region decreased. The length of the abdominal region remained constant to a certain body length and subsequently showed a marked increase, and that of the tail region decreased consistently. The length of dorsal fin and flukes decreased consistently, whereas that of the flippers remained constant to a certain body length and subsequently decreased. The relative growth pattern determined by an allometric analysis was positive for the head region but negative for the lower body part, flippers, flukes, and dorsal fin. Both sexes demonstrated the same growth pattern, but the coefficients differed. This is the first study to investigate developmental changes in the body proportions of Bryde’s whales using more than 700 specimens covering a wide body length range. We believe that the results of this study will contribute to various research fields, including taxonomy, phylogeny, and feeding ecology of this species.

Community-based population monitoring for large baleen whales:the case study of Bryde’s whale in Beibu Gulf of China

Citizen science is a popular method for the long-term monitoring of the distribution of wild animals.The application of these methods in different species and environments still poses challenges,especially for aquatic animals.In this study,we investigated the distribution of the Bryde’s whale(Balaenoptera edeni)in the Beibu Gulf of China by using scientific boat-based surveys and citizen science approaches using 2 different methods of data collection.First,we built our mobile app(Whale Guard)and installed it on fishermen’s phones.Second,we used a popular instant messaging app(WeChat)to create an online fisherman community.We found that the mobile phone app collected far fewer reports(5 reports)than the online community group(42 reports,P<0.01).By using a variety of incentives,we maintained the fisherman’s community’s activity without significant user loss(P<0.01).We also found that the locations collected by social media applications in this study were consistent with observations from scientific boat-based transect surveys.The sightings distribution of Bryde’s whales differed from those in previous surveys in that they were present across larger areas.Social media apps reported that 69%of reports was confirmed by more than one person,whereas Whale Guard reports were much lower(0,P<0.001).Community-based citizen science can greatly contribute to the long-term monitoring of Bryde’s whales,and it has successfully overcome the challenges of data accessibility,accuracy,and fragmentation.Our study shows how to appropriately use citizen science in different community groups and community-based approaches make them useful for large baleen whale surveys.