Dietary studies provide key insights into threats and changes within ecosystems and subsequent impacts on focal species. Diet is particularly challenging to study within marine environments and therefore is often poorly understood. Here, we examined the diet of stranded and bycaught loggerhead (Caretta caretta) and green turtles (Chelonia mydas) in North Cyprus (35.33° N, 33.47° E) between 2011 and 2019. A total of 129 taxa were recorded in the diet of loggerhead turtles (n = 45), which were predominantly carnivorous (on average 72.1% of dietary biomass), foraging on a large variety of invertebrates, macroalgae, seagrasses and bony fish in low frequencies. Despite this opportunistic foraging strategy, one species was particularly dominant, the sponge Chondrosia reniformis (21.5%). Consumption of this sponge decreased with increasing turtle size. A greater degree of herbivory was found in green turtles (n = 40) which predominantly consumed seagrasses and macroalgae (88.8%) with a total of 101 taxa recorded. The most dominant species was a Lessepsian invasive seagrass, Halophila stipulacea (31.1%). This is the highest percentage recorded for this species in green turtle diet in the Mediterranean thus far. With increasing turtle size, the percentage of seagrass consumed increased with a concomitant decrease in macroalgae. Seagrass was consumed year-round. Omnivory occurred in all green turtle size classes but reduced in larger turtles (> 75 cm CCL) suggesting a slow ontogenetic dietary shift. Macroplastic ingestion was more common in green (31.6% of individuals) than loggerhead turtles (5.7%). This study provides the most complete dietary list for marine turtles in the eastern Mediterranean.

饮食研究为生态系统内的威胁和变化以及对重点物种的后续影响提供了重要的见识。在海洋环境中研究饮食尤其具有挑战性，因此人们对其了解甚少。在这里，我们研究了2011年至2019年之间北塞浦路斯（北纬35.33°，东经33.47°）的搁浅和兼捕的（Caretta caretta）和绿海龟（Chelonia mydas）的饮食。 食肉龟（n = 45）主要食肉（平均占食物生物量的72.1％），它们以低频率觅食各种无脊椎动物，大型藻类，海草和骨鱼。尽管采取了这种机会性的觅食策略，但其中一个物种尤其占优势，海绵肾形软骨病（21.5％）。随着海龟大小的增加，这种海绵的消耗量减少了。在 主要消耗海草和大型藻类（88.8％）的绿海龟（n = 40）中发现了较高的草食性，共记录了101个分类单元。最主要的物种是较少的入侵性海草，嗜盐草（Halophila stipulacea）（31.1％）。这是迄今为止在地中海绿海龟饮食中该物种记录的最高百分比。随着海龟大小的增加，海藻消耗的百分比增加，同时大型藻类减少。海草一年四季都被消耗掉。在所有绿海龟大小类别中均发生杂食，但在较大的海龟（> 75 cm CCL）中杂食动物减少，表明个体发育的饮食变化缓慢。绿皮动物（占个体的31.6％）比属龟（5.7％）更常见于大塑性食物的摄入。这项研究为地中海东部的海龟提供了最完整的饮食清单。