Details on the transport of European eel larvae through the Strait of Gibraltar into the Mediterranean Sea.

Numbers of European glass eels (Anguilla anguilla) monitored along the Atlantic and Mediterranean coasts of Europe currently serve as the main stock indicator in assessment of this critically endangered species. Spawning, however, takes place exclusively in the Sargasso Sea, several thousand kilometers away. The beginning of its complex lifecycle is characterized by a distant and lengthy larval drift, before the young-of-the-year reach the monitoring stations at the European coasts.

Temperature and pressure dependency of oxygen consumption during long-term sustained swimming of European eels.

Many aspects of the typically 5000-10,000 km spawning migration of the European eel (Anguilla anguilla) remain unknown. As part of this migration, eels undertake extensive diurnal vertical migrations to depths below 1000 m, being exposed to a wide range of temperatures and hydrostatic pressures. In this experimental study, we exposed eels to different combinations of temperature (12-20°C) and pressure (100--800 kPa) during long-term sustained swimming (32-47 days).

Abandoned, lost or otherwise discarded fishing gear (ALDFG) as part of marine litter at the seafloor of the Baltic Sea - Characterization, quantification, polymer composition and possible impact.

As an important part of marine litter at the seafloor "Abandoned, lost, discarded or otherwise lost fishing gear" (ALDFG) is gaining increasing attention in environmental assessments. Within this study marine litter at the seafloor of the Baltic Sea was quantified and characterized with special regard to fishery as source. Litter items (LI) were collected within fishery catches by bottom trawling during three cruises in 2020 and 2021.

Temporal trends of mercury levels in fish (dab, Limanda limanda) and sediment from the German Bight (North Sea) in the period 1995-2020.

As a toxic and harmful global pollutant, mercury (Hg) enters the marine environment through natural sources, and human activities. It bioaccumulates through the food chain and therefore, Hg is of great importance for environmental monitoring. This study aims to answer the question if Hg contamination in fish and sediment from the German Bight follows temporal trends.

Metagenomic Analysis of the Gastrointestinal Microbiota of L. Originating from a Chemical Munition Dump Site.

Several hundred thousand tonnes of munitions containing chemical warfare agents (CWAs) are lying on the seafloor worldwide. CWAs have started leaking from corroded munitions, and their presence in the environment and in organisms inhabiting dump sites has been detected. The presence of CWAs in the water negatively affects fish, macrobenthos and free-living bacteria.

Mapping silver eel migration routes in the North Sea.

Recent developments in tracking technology resulted in the mapping of various marine spawning migration routes of the European eel (Anguilla anguilla). However, migration routes in the North Sea have rarely been studied, despite many large European rivers and hence potential eel growing habitat discharge into the North Sea. In this study, we present the most comprehensive map to date with migration routes by silver European eels in the North Sea and document for the first time successful eel migration through the English Channel.

A novel hyperbaric swimming respirometer allows the simulation of varying swimming depths in fish respirometry studies.

The understanding of swimming physiology and knowledge on the metabolic costs of swimming are important for assessing effects of environmental factors on migratory behavior. Swim tunnels are the most common experimental setups for measuring swimming performance and oxygen uptake rates in fishes; however, few can realistically simulate depth and the changes in hydrostatic pressure that many fishes experience, e.g.

Visual Gene Expression Reveals a cone-to-rod Developmental Progression in Deep-Sea Fishes.

Vertebrates use cone cells in the retina for color vision and rod cells to see in dim light. Many deep-sea fishes have adapted to their environment to have only rod cells in the retina, while both rod and cone genes are still preserved in their genomes. As deep-sea fish larvae start their lives in the shallow, and only later submerge to the depth, they have to cope with diverse environmental conditions during ontogeny.

Swimming under elevated hydrostatic pressure increases glycolytic activity in gas gland cells of the European eel.

In spite of many decades of research, the spawning migration of the European eel Anguilla anguilla from the European coast to the Sargasso Sea remains a mystery. In particular, the role of the swimbladder as a buoyancy regulating structure is not yet understood. In this study, we exercised silver eels in a swim tunnel under elevated hydrostatic pressure.

Bone resorption and body reorganization during maturation induce maternal transfer of toxic metals in anguillid eels.

During their once-in-a-lifetime transoceanic spawning migration, anguillid eels do not feed, instead rely on energy stores to fuel the demands of locomotion and reproduction while they reorganize their bodies by depleting body reserves and building up gonadal tissue. Here we show how the European eel () breaks down its skeleton to redistribute phosphorus and calcium from hard to soft tissues during its sexual development. Using multiple analytical and imaging techniques, we characterize the spatial and temporal degradation of the skeletal framework from initial to final gonadal maturation and use elemental mass ratios in bone, muscle, liver, and gonadal tissue to determine the fluxes and fates of selected minerals and metals in the eels' bodies.

Spawning by the European eel across 2000 km of the Sargasso Sea.

It has been known for about a century that European eels have a unique life history that includes offshore spawning in the Sargasso Sea about 5000-7000 km away from their juvenile and adult habitats in Europe and northern Africa. Recently hatched eel larvae were historically collected during Danish, German and American surveys in specific areas in the southern Sargasso Sea. During a 31 day period of March and April 2014, Danish and German research ships sampled for European eel larvae along 15 alternating transects of stations across the Sargasso Sea.

Metamorphosis and transition between developmental stages in European eel (Anguilla anguilla, L.) involve epigenetic changes in DNA methylation patterns.

The life history of the European eel (Anguilla anguilla, L.) is characterized by a series of metamorphoses and transitions that provoke drastic morphological changes. Most of these changes go along with the catadromous life cycle in eels, involving extensive physiologically adaptations.

Low larval abundance in the Sargasso Sea: new evidence about reduced recruitment of the Atlantic eels.

The European eel Anguilla anguilla has shown decreased recruitment in recent decades. Despite increasing efforts to establish species recovery measures, it is unclear if the decline was caused by reduced numbers of reproductive-stage silver eels reaching the spawning area, low early larval survival, or increased larval mortality during migration to recruitment areas. To determine if larval abundances in the spawning area significantly changed over the past three decades, a plankton trawl sampling survey for anguillid leptocephali was conducted in March and April 2011 in the spawning area of the European eel that was designed to directly compare to collections made in the same way in 1983 and 1985.

Environmentally induced migration: the importance of food.

The decision to migrate or not is regarded as genetically controlled for many invertebrate and vertebrate taxa. Here, we show that the environment influences this decision. By reciprocally transplanting brown trout (Salmo trutta L.