Use of geochemical tools for tracing the geographic origin of Hippocampus guttulatus

• Autor(a) principal: Cabral, Ana Elisa Garcia
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/30427
• topic: Trace elements; Geochemical profile; Bony plates; Illegal fishing; Conservation; Seahorse

Seahorses within genus Hippocampus are currently exposed to a wide range of anthropogenic pressures, such as habitat loss, bycatch and fisheries targeting seahorses. In fact, millions of individuals are sold every year to overcome the demand, mainly for Traditional Chinese Medicine (TCM), curios and aquarium purposes. In spite the restrictions imposed by several countries in the extraction, exportation and importation of seahorses, the illegal capture and trade still occur. A tool used for the traceability of geographic origin of marine living resources, is the analysis of elemental fingerprints (EF) from mineral structures. The EF of the mineral structure, that includes an armor composed by bony plates, was determined in cultured seahorses of the species Hippocampus gutullatus from two different origins (Galicia and Ria Formosa). It was also evaluated the suitability of these EF for the traceability of the geographic origin of this species. The following elements, Al (aluminium), Ba (barium), Ce (cerium), Cr (chromium), Cu (copper), Fe (iron), K (potassium), Mg (magnesium), Mn (manganese), Na (sodium), Ni (nickel), P (phosphorus), Sr (strontium) and Zn (zinc), were considered and expressed in ratios referent to the quantity of detected Ca (calcium). The EF from the bones, belonging to the head, trunk, dorsal fin and tail, of seahorses from Galicia, were confronted to the EF of conspecifics processed as a whole from the same location, presenting always significant differences in their EF (ANOSIM, p=0.001). Thus, none of these body parts is a perfect proxy to the whole body. The analysis of body parts of seahorses from Galicia and Ria Formosa revealed that the dorsal fin was the one exhibiting the higher ratios of Al/Ca, Ba/Ca, Ce/Ca, Cr/Ca, Cu/Ca, Fe/Ca and Mn/Ca. A CAP analysis that included the four body parts, from both locations, correctly classified all trunk replicates. An ANOVA analysis, for each individual elemental ratio and that included the same body parts, from both locations, indicated that, in general, the EF were significantly different. An additional CAP analysis to validate the trunk as a model for the traceability of the geographic origin, resulted in the correct classification of all whole body replicates from Galicia. A CAP analysis, which included six seahorse body portions (without one or two body parts), to simulate the apprehension of individuals with body parts missing, resulted in the correct attribution of all body portions to the respective origin (Galicia or Ria Formosa). The EF from the bony structure of Hippocampus guttulatus, has the potential of being an important tool for the traceability of the geographic origin of organisms, apprehended from illegal fishing and trade. The results from this preliminary work will guide the following experimental essays that intend to assess the geographic origin of wild organisms captured illegally