fc36b496d3d76d9d8633c3a70758ebe3 vetsci-12-00711-v2.pdf daf6e8a03f1aa3788937977ab415c26e97c326b0 vetsci-12-00711-v2.pdf 0692e335e389adc0193622210e942128a5cfd033e664dd0b3e6dcd192b6e1876 vetsci-12-00711-v2.pdf Title: Bycatch in Cetaceans from the North-Western Mediterranean Sea: Retrospective Study of Lesions and Utility of Bycatch Criteria Subject: Bycatch is the most common cause of death of small delphinids worldwide, including the Mediterranean Sea. The diagnosis of bycatch as cause of death in stranded cetaceans depends on the cumulative presence of multiple findings, termed bycatch criteria. In this study, we retrospectively evaluated the presence of bycatch criteria in 138 necropsied cetaceans, 136 stranded and 2 confirmed bycaught, in the Catalan Mediterranean Sea across a 13-year period. With the aim of identifying the most specific and reliable bycatch criteria, the animals’ cause of death was classified as either bycaught or other causes. Animals were necropsied according to standard procedures with complete histopathological examination and ancillary diagnostic techniques. We reviewed the necropsy reports and photographs of 138 cetaceans of seven species. Bycatch had been determined as the cause of death/stranding in 40 (29%) necropsied cetaceans. Both sexes were equally represented in the bycatch group. Bycatch was diagnosed in the Mediterranean common bottlenose dolphin (10/14; 71.4%), striped dolphin (29/108; 26.9%), and Risso’s dolphin (1/11; 9.1%). Sixty-seven out of 98 (68.3%) cetaceans that had been classified as non-bycatch had one or two bycatch criteria. Cetaceans with two and three major criteria had an overlap of causes of death, as some animals were diagnosed with bycatch and others with other causes of mortality. Animals with four criteria were invariably diagnosed as being bycaught. Recent feeding, absence of disease, good nutritional status, marks of fishing gear, multiorgan intravascular gas bubbles, hyphema and amputations or sharp incisions presumably inflicted by humans were significantly more likely to result in a diagnosis of bycatch, while loss of teeth and cranial fractures were not. None of the dolphins diagnosed as bycatch had ingested fishing gear. Our results highlight the relevance of bycatch as the cause of death of dolphins in the Mediterranean and suggest that some criteria traditionally linked to bycatch are not specific for bycatch in our region. Keywords: necropsy; strandings; pathology; bycatch; fisheries; dolphin; cetacean;Mediterranean Author: Laura Martino, Mariona Leiva Forns, Marina Cid Cañete, Lola Pérez, Cèlia Pradas and Mariano Domingo Creator: LaTeX with hyperref Producer: pdfTeX-1.40.25; modified using OpenPDF 1.4.2 CreationDate: Wed Jul 30 03:48:44 2025 CEST ModDate: Wed Jul 30 03:51:08 2025 CEST Custom Metadata: yes Metadata Stream: no Tagged: no UserProperties: no Suspects: no Form: none JavaScript: no Pages: 15 Encrypted: no Page size: 595.276 x 841.89 pts (A4) Page rot: 0 File size: 1292514 bytes Optimized: no PDF version: 1.5 name type encoding emb sub uni object ID ------------------------------------ ----------------- ---------------- --- --- --- --------- WYEKQU+VnURWPalladioL-Bold Type 1 Custom yes yes yes 88 0 GZFLMF+URWPalladioL-Ital Type 1 Custom yes yes yes 89 0 NAQVUQ+URWPalladioL-Bold Type 1 Custom yes yes yes 90 0 SSXPJJ+VnURWPalladioL Type 1 Custom yes yes yes 91 0 XJKQYN+URWPalladioL-Roma Type 1 Custom yes yes yes 92 0 DJAFDL+PalatinoLinotype-Italic CID TrueType Identity-H yes yes yes 184 0 DJAFBK+PalatinoLinotype-Bold CID TrueType Identity-H yes yes yes 185 0 DJAFDK+PalatinoLinotype-Roman CID TrueType Identity-H yes yes yes 186 0 PDTLUH+CMSY10 Type 1 Builtin yes yes yes 232 0 WBVKDJ+URWPalladioL-BoldItal Type 1 Custom yes yes yes 257 0 DJAFDL+PalatinoLinotype-Italic CID TrueType Identity-H yes yes yes 272 0 DJAFBK+PalatinoLinotype-Bold CID TrueType Identity-H yes yes yes 273 0 DJAFDK+PalatinoLinotype-Roman CID TrueType Identity-H yes yes yes 274 0 DJAFDL+PalatinoLinotype-Italic CID TrueType Identity-H yes yes yes 248 0 DJAFBK+PalatinoLinotype-Bold CID TrueType Identity-H yes yes yes 249 0 DJAFDK+PalatinoLinotype-Roman CID TrueType Identity-H yes yes yes 250 0 Jhove (Rel. 1.28.0, 2023-05-18) Date: 2025-09-10 03:49:10 CEST RepresentationInformation: vetsci-12-00711-v2.pdf ReportingModule: PDF-hul, Rel. 1.12.4 (2023-03-16) LastModified: 2025-09-09 10:50:27 CEST Size: 1292514 Format: PDF Version: 1.5 Status: Well-Formed and valid SignatureMatches: PDF-hul MIMEtype: application/pdf PDFMetadata: Objects: 553 FreeObjects: 1 IncrementalUpdates: 0 DocumentCatalog: ViewerPreferences: HideToolbar: false HideMenubar: false HideWindowUI: false FitWindow: true CenterWindow: false DisplayDocTitle: false NonFullScreenPageMode: UseNone Direction: L2R ViewArea: CropBox ViewClip: CropBox PrintArea: CropBox PageClip: CropBox PageLayout: SinglePage PageMode: UseNone Outlines: Item: Title: Introduction Item: Title: Materials and Methods Children: Item: Title: Cetaceans Investigated and Necropsy Procedure Item: Title: Criteria Used for Diagnosis of Bycatch Item: Title: Results Children: Item: Title: Causes of Death or Stranding Item: Title: Bycatch Criteria Detected Item: Title: Bycatch Diagnosis by Sex and Age Group Item: Title: Effect of CT Scan Use on Bycatch Diagnosis Item: Title: Bycatch Diagnosis by Species Item: Title: Discussion Item: Title: References Info: Title: Bycatch in Cetaceans from the North-Western Mediterranean Sea: Retrospective Study of Lesions and Utility of Bycatch Criteria Author: Laura Martino, Mariona Leiva Forns, Marina Cid Cañete, Lola Pérez, Cèlia Pradas and Mariano Domingo Subject: Bycatch is the most common cause of death of small delphinids worldwide, including the Mediterranean Sea. The diagnosis of bycatch as cause of death in stranded cetaceans depends on the cumulative presence of multiple findings, termed bycatch criteria. In this study, we retrospectively evaluated the presence of bycatch criteria in 138 necropsied cetaceans, 136 stranded and 2 confirmed bycaught, in the Catalan Mediterranean Sea across a 13-year period. With the aim of identifying the most specific and reliable bycatch criteria, the animals’ cause of death was classified as either bycaught or other causes. Animals were necropsied according to standard procedures with complete histopathological examination and ancillary diagnostic techniques. We reviewed the necropsy reports and photographs of 138 cetaceans of seven species. Bycatch had been determined as the cause of death/stranding in 40 (29%) necropsied cetaceans. Both sexes were equally represented in the bycatch group. Bycatch was diagnosed in the Mediterranean common bottlenose dolphin (10/14; 71.4%), striped dolphin (29/108; 26.9%), and Risso’s dolphin (1/11; 9.1%). Sixty-seven out of 98 (68.3%) cetaceans that had been classified as non-bycatch had one or two bycatch criteria. Cetaceans with two and three major criteria had an overlap of causes of death, as some animals were diagnosed with bycatch and others with other causes of mortality. Animals with four criteria were invariably diagnosed as being bycaught. Recent feeding, absence of disease, good nutritional status, marks of fishing gear, multiorgan intravascular gas bubbles, hyphema and amputations or sharp incisions presumably inflicted by humans were significantly more likely to result in a diagnosis of bycatch, while loss of teeth and cranial fractures were not. None of the dolphins diagnosed as bycatch had ingested fishing gear. Our results highlight the relevance of bycatch as the cause of death of dolphins in the Mediterranean and suggest that some criteria traditionally linked to bycatch are not specific for bycatch in our region. 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