Ray Collier Country Diary- Eels
Eels - 24th November 2008
Adult freshwater eels, sometimes called yellow eels, are dark brown along the back and more yellow below. Its serpentine form and slimy body is unmistakable and it is unusual in that the fins extend all along the body to the tail. The front part of the fish is rounded but towards the tail it is more flattened. The scales are transparent, small and deeply-embedded in the skin and laid down as concentric rings. The migration of eels and their life history has been one of the all-time wildlife mysteries and the very early stages are still being solved. The true story was not revealed until the first three decades of the 20th century and it began 2,500 miles away in the Sargasso Sea - so called after the floating seaweed of that name. The eggs have never been found nor, for that matter, no spawning eel has ever been seen. The smallest eels found in the Sargasso were about half an inch long with remains of their yolk sacs which means they were close to their birthplace. They soon start drifting across the Atlantic and reach the coasts of Europe. Round the British coasts the young eels will stay in brackish water for a few weeks and then they begin to move into freshwater. At this stage they are called elvers and in some rivers millions move with the tides, and their exploitation as food has been overtaken by their use to stock rivers in other countries. In the Highlands, these elvers can be seen entering water courses from rivers to burns, some of the latter only two feet across. These tiny eels have been recorded several miles inland trying to scale the dam walls of hydro-electric schemes. They can wriggle through wet moss on the side of waterfalls and they can scale wet, almost vertical, rocks. They are probably the most widespread fish in the Highlands, for a number of reasons, although mainly unrecorded because of their nocturnal and mud dwelling habits. One of these is that large eels have extraordinary means of reaching even land-locked water bodies such as ponds and lochs. The slimy coat of mucus prevents drying and water loss and helps them survive out of water for long periods and they simply wriggle from one area to another. The eel in the photograph was well away from water but it was raining. The British rod- caught record is about 11 lbs but much larger eels have been found either dead or when a loch is drained. Eels have been found weighing 23 lbs and 27 lbs with both being over five feet long. When underwater cameras have explored Loch Ness there have been many sightings of huge eels sliding away on the bottom. Their food depends on their size and a wide range of prey is taken such as snails, frogs, tadpoles, fish eggs and smaller eels. They have many predators, particularly in the smaller stages, and they are a common prey of goosanders and mergansers as well as pike and ferox trout. Herons can often be seen feeding on eels along the Moray Firth and the birds even have special feathers that produce a powder that is used to coagulate the slime of eels so that it can be removed by the bird’s claw. Some eels mature by the time they are nine years old but others have been recorded over 50 years old before they return to the sea and back to the Sargasso to lay eggs and die. When they start the return journey they change colour and are known as silver eels because they are grey backed and silver bellied.
Adult freshwater eels, sometimes called yellow eels, are dark brown along the back and more yellow below. Its serpentine form and slimy body is unmistakable and it is unusual in that the fins extend all along the body to the tail. The front part of the fish is rounded but towards the tail it is more flattened. The scales are transparent, small and deeply-embedded in the skin and laid down as concentric rings. The migration of eels and their life history has been one of the all-time wildlife mysteries and the very early stages are still being solved. The true story was not revealed until the first three decades of the 20th century and it began 2,500 miles away in the Sargasso Sea - so called after the floating seaweed of that name. The eggs have never been found nor, for that matter, no spawning eel has ever been seen. The smallest eels found in the Sargasso were about half an inch long with remains of their yolk sacs which means they were close to their birthplace. They soon start drifting across the Atlantic and reach the coasts of Europe. Round the British coasts the young eels will stay in brackish water for a few weeks and then they begin to move into freshwater. At this stage they are called elvers and in some rivers millions move with the tides, and their exploitation as food has been overtaken by their use to stock rivers in other countries. In the Highlands, these elvers can be seen entering water courses from rivers to burns, some of the latter only two feet across. These tiny eels have been recorded several miles inland trying to scale the dam walls of hydro-electric schemes. They can wriggle through wet moss on the side of waterfalls and they can scale wet, almost vertical, rocks. They are probably the most widespread fish in the Highlands, for a number of reasons, although mainly unrecorded because of their nocturnal and mud dwelling habits. One of these is that large eels have extraordinary means of reaching even land-locked water bodies such as ponds and lochs. The slimy coat of mucus prevents drying and water loss and helps them survive out of water for long periods and they simply wriggle from one area to another. The eel in the photograph was well away from water but it was raining. The British rod- caught record is about 11 lbs but much larger eels have been found either dead or when a loch is drained. Eels have been found weighing 23 lbs and 27 lbs with both being over five feet long. When underwater cameras have explored Loch Ness there have been many sightings of huge eels sliding away on the bottom. Their food depends on their size and a wide range of prey is taken such as snails, frogs, tadpoles, fish eggs and smaller eels. They have many predators, particularly in the smaller stages, and they are a common prey of goosanders and mergansers as well as pike and ferox trout. Herons can often be seen feeding on eels along the Moray Firth and the birds even have special feathers that produce a powder that is used to coagulate the slime of eels so that it can be removed by the bird’s claw. Some eels mature by the time they are nine years old but others have been recorded over 50 years old before they return to the sea and back to the Sargasso to lay eggs and die. When they start the return journey they change colour and are known as silver eels because they are grey backed and silver bellied.
posted by Corinne @ 11:39 AM
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