The fishing industry is a very important source of food and will be also used in the future. Therefore it is essential to study the impact of fishery on marine mammals. Whales (cetaceans) interact with fishing vessels because the catch is easy prey for them. Cetaceans are caught everyday as bycatch and often get entangled in fishing gear. The result could be starvation, drowning or infection of the cetacean. This study focused on injuries on dorsal fins on orcas occurring in Norwegian waters. In Norway, Tiu Similä, Sanna Kuningas and Norwegian Orca Survey have taken pictures and matched these to an ID-catalogue of orcas. This ID-catalogue was used in this study. 842 pictures of individuals were categorized by the size of the injury on the dorsal fin and the location of the nicks. Percent of total amount of injured males and females/subadults was estimated. Females and subadults were grouped together because of the difficulties of distinguishing the subadults from the females. 34% of the females/subadults and 54% of the males had nicks on their dorsal fins. The amount of damaged fins was 2% in females/subadults and 4% in males. This result was expected as my theory was that orca males swim closer to fishing boats, than females/subadults do. The most common location of the nicks was the upper hind part. It might be because that is the thinnest part of the dorsal fin.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:hh-36469 |
| Date | January 2017 |
| Creators | Ruusuvuori, Aino |
| Publisher | Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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