Burrowing behaviour of the European eel (Anguilla anguilla): Effects of life stage

Abstract

The European eel (Anguilla anguilla) is a fascinating species, exhibiting a complex life cycle. The species is, however, listed as critically endangered on the IUCN Red List due to an amalgam of factors, including habitat loss. This study investigated the burrowing behaviour and substrate preference of glass, elver and yellow stages of A. anguilla. Preference was determined by introducing eels in aquaria with different substrates and evaluating the chosen substrate for burrowing. In addition, burrowing was recorded using a camera in all substrate types and analysed for kinematics. The experiments showed that all of these life stages sought refuge in the sediments with particle sizes ranging from sand to coarse gravel. Starting from a resting position, they shook their head horizontally in combination with rapid body undulations until half of their body was within the substrate. High-speed X-ray videography revealed that once partly in the sediment, eels used only horizontal head sweeps to penetrate further, without the use of their tail. Of the substrates tested, burrowing performance was highest in fine gravel (diameter 1-2 mm; lower burrowing duration, less body movements and/or lower frequency of movements), and all eels readily selected this substrate for burrowing. However, glass eels and elvers were able to use coarse gravel (diameter >8 mm) because their smaller size allowed manoeuvring through the spaces between the grains. Further, burrowing performance increased with body size: glass eels required more body undulations compared to yellow eels. Interestingly, the urge to hide within the sediment was highest for glass eels and elvers. Documentation of substrate preference and burrowing behaviour of A. anguilla provides new information about their potential habitat use. Considering that habitat alterations and deteriorations are partly responsible for the decline of the eel, this information can contribute to the development of more effective conservation measures.

Functional diversity of snake locomotor behaviors: A review of the biological literature for bioinspiration

“…Additionally, the mechanics of burrowing through mud remains a particularly open question, likely due to the difficulty of experimental preparations involving damp or wet media. Several studies have shed light on the mechanics of aquatic and mud burrowing in elongate invertebrates, [142][143][144][145] although size differences likely lead to very different mechanical environments for most of these species compared to snakes; a few studies have examined the mechanics of aquatic burrowing in eels, 146,147 which we would expect to be more similar to snakes. Recent technological advances combined with clever experimental setups should provide opportunities for researchers to make major progress in the study of fossorial snake locomotion in the coming years.…”

Pengaruh Jenis Substrat terhadap Pertumbuhan dan Kelangsungan Hidup Glass Eel Anguilla bicolor pacifica

“…Mereka bolak-balik mengambil makanan sampai makanan habis. Fenomena tingkah laku dalam merespon pakan dan substrat seperti dalam studi ini juga ditunjukkan oleh A. anguilla (Degerman et al, 2019;Steendam et al, 2020) dan A. japonica (Dou dan Tsukamoto, 2003).…”

Transcriptional Contribution of Transposable Elements in Relation to Salinity Conditions in Teleosts and Silencing Mechanisms Involved

“…The giant marbled eel Anguilla marmorata is a catadromous species widely distributed in tropical, subtropical, and temperate areas that moves from freshwater to salt water for spawning [13]. The chum salmon Oncorhynchus keta is an anadromous species that spends much of its life in salt water and goes up rivers to spawn [14,15].…”