Glycosaminoglycans (GAGs) play a crucial role due to their significant biomedical functions. Chondroitin sulfate (CS) and dermatan sulfate (DS), the main representative family of GAGs, were extracted and purified from garfish (Belone belone) by-products, i.e., skin (GSB), bones (GCB), and heads (GHB), and their composition and anticoagulant activity were investigated. CS/DS were purified by ion-exchange chromatography with yields of 8.1% for heads, 3.7% for skin, and 1.4% for bones. Cellulose acetate electrophoresis was also explored for analyzing the extracted CS/DS. Interestingly, GHB, GSB, and GCB possessed sulfate contents of 21 ± 2%, 20 ± 1%, and 20 ± 1.5%, respectively. Physico-chemical analysis showed that there were no significant differences (p > 0.05) between the variances for sulfate, uronic acid, and total sugars in the GAGs extracted from the different parts of fish. Disaccharide analysis by SAX-HPLC showed that the GSB and GCB were predominately composed of ΔDi-4S [ΔUA-GalNAc 6S] (74.78% and 69.22%, respectively) and ΔDi-2,4S [ΔUA2S-GalNAc 4S] (10.92% and 6.55%, respectively). However, the GHB consisted of 25.55% ΔDi-6S [ΔUA-GalNAc 6S] and 6.28% ΔDi-2,6S [ΔUA2S-GalNAc 4S]. Moreover, classical anticoagulation tests were also used to measure their anticoagulant properties in vitro, which included the activated partial thromboplastin time, prothrombin time, and thrombin time. The CS/DS isolated from garfish by-products exhibited potent anticoagulant effects. The purified CS/DS showed exceptional anticoagulant properties according to this research and can be considered as a new agent with anticoagulant properties.

A total of 35 common garfish, Belone belone (Linnaeus, 1761), were studied for metazoan parasites on their spawning grounds in the western Baltic Sea. Nine parasite species were found, and six new locality records could be established for German coastal waters (Axine belones, Monogenea; Proteocephalus sp., Cestoda; Anisakis simplex (s.s.), Contracaecum rudolphii A and Hysterothylacium aduncum, Nematoda; Echinorhynchus gadi, Acanthocephala). For the first time, the marine ectoparasite A. belones was recorded from the gills of garfish inside the Baltic Sea, indicating its ability to survive the spawning migration as well as the brackish water conditions at its reproduction grounds. This is alike the endohelminth A. simplex (s.s.), that was identified by molecular analyses of the internal transcribed spacer (ITS-1, 5.8S, ITS-2) region. Almost all isolated metazoans were parasites commonly recorded from the northeast Atlantic Ocean and the North Sea. The lower number of typical generalist Baltic Sea parasites indicates the rapid migration of common garfish onto the spawning grounds, reducing the access and uptake of these species.