June 21, 2024

Whale Poaching Detection Based on Microscopic Characteristics of Bottlenose Dolphins’ (Tursiops truncatus) Bone Fragments


Manuela Zadravec, Zvonimir Kozarić, Snježana Kužir, Mario Mitak, Tomislav Gomerčić, Miroslav Benić, and Martina Đuras


Abstract: Although many countries prohibit whaling, it remains a significant cause of whale population decline. Whale meal, likely from whales killed during illegal whaling or caught accidentally, can appear in a fish meal as a contaminant detectable by microscopic examination of bone fragments. To provide a rigorous basis for such a detection, microscopic characterization of bone fragments of 10 female and 10 male, less than a year old to 21-year-old bottlenose dolphins (Tursiops truncatus), a widespread cetacean species herein used as a whale model, was performed and compared to the reference bone fragments of fish, ruminants, poultry, and pigs. The processing of bones mimicked the process used in the production of meat and bone meals, while their description was based on qualitative characteristics (i.e., the shape of a bone fragment; the shape, density, and distribution of osteocyte lacunae; and the distribution and density of canaliculae). Bottlenose dolphin bone fragments are smoothly contoured. Their elliptical osteocyte lacunae are clearly visible, while the canaliculae radiate from the lacunae in all directions. The comparison of these qualitative bone characteristics with that of other vertebrata under study revealed that bottlenose dolphin bone fragments can definitely be differentiated from that of fish, may be differentiated from that of poultry and pig, but cannot be differentiated from that of ruminants. Measurements of the osteocyte lacunae showed the lacunar length to be strongly associated with an animal’s age and lacunar shape, while their width was strongly associated with an animal’s gender and lacunar shape. The results indicate the possibility of detecting a whale meal admixture in a fish meal using light microscopy, which should be followed by PCR to allow for the identification of the admixture source.
Key Words: whale poaching, bottlenose dolphin, Tursiops truncatus, osteocyte
Document: Article
DOI: https://doi.org/10.1578/AM.44.5.2018.519
Page Numbers: 519-528

Info SKU: Vol__44__Iss__5_Zadravec Category: