Harbour porpoises (Phocoena phocoena) are the only native cetacean species in the German North and Baltic Seas and the final host of Anisakis (A.) simplex, which infects their first and second gastric compartments and may cause chronic ulcerative gastritis. Anisakis simplex belongs to the family Anisakidae (Ascaridoidea, Rhabditida) as well as the phocine gastric nematode species Pseudoterranova (P.) decipiens and Contracaecum (C.) osculatum. These nematode species are the main causative agents for the zoonosis anisakidosis. The taxonomy of these genus with life cycles including crustaceans and commercially important fish is complex because of the formation of sibling species. Little is known about anisakid species infecting porpoises in the study area. Mature nematodes and larval stages are often identifiable only by molecular methods due to high morphological and genetic similarity. The restriction fragment length polymorphism (RFLP) method is an alternative to sequencing and was applied to identify anisakid nematodes found in harbour porpoises from the North Sea, Baltic Sea and North Atlantic to species level for the first time. In the study areas, five gastric nematodes from different harbour porpoise hosts were selected to be investigated with restriction enzymes HinfI, RsaI and HaeIII, which were able to differentiate several anisakid nematode species by characteristic banding patterns. Anisakis simplex s. s. was the dominant species found in the North Sea and Baltic porpoises, identified by all three restriction enzymes. Additionally, a hybrid of A. simplex s. s. and A. pegreffii was determined by HinfI in the North Sea samples. Within the North Atlantic specimens, A. simplex s. s., P. decipiens s. s. and Hysterothylacium (H.) aduncum were identified by all enzymes. This demonstrates the value of the RFLP method and the chosen restriction enzymes for the species identification of a broad variety of anisakid nematodes affecting the health of marine mammals.

港鼠（Phocoena phocoena）是德国北海和波罗的海唯一的本地鲸类物种，也是最终的Anisakis（A .）单纯形宿主，感染了它们的第一个和第二个胃腔，可能引起慢性溃疡性胃炎。Anisakis simplex属于Anisakidae家族（Ascaridoidea，Rhabditida），还属于光胃线虫物种Pseudoterranova（P.）decipiens和Contracaecum（C.）osculatum。。这些线虫种类是人畜共患病anisakidosis的主要病原体。这些类的生命周期包括甲壳类和商业上重要的鱼类的分类很复杂，因为同胞物种的形成。在研究区域内，关于茴香皮感染海豚的物种知之甚少。由于高度的形态和遗传相似性，成熟的线虫和幼虫阶段通常只能通过分子方法鉴定。限制性片段长度多态性（RFLP）方法是测序的另一种方法，首次用于鉴定从北海，波罗的海和北大西洋的港口海豚到物种水平中首次发现的茴香线虫。在研究区域，选择了五个来自不同港口海豚宿主的胃线虫，用限制酶进行研究。Hinf I，Rsa I和Hae III，它们能够通过特征性条带模式区分几种茴香线虫。Anisakis simplex ss是在北海和波罗的海豚中发现的优势种，由所有三种限制性内切酶鉴定。此外，是A的混合体。单纯ss和一个。pegreffii由Hinf I在北海样品中测定。在北大西洋标本中，A。单纯形ss，P。杜英ss和宫脂（ħ。）羊膜被所有酶鉴定。这证明了RFLP方法和选择的限制性内切酶对鉴定影响海洋哺乳动物健康的各种茴香线虫的价值。