Blood-sucking sea lampreys feed on prey as big as minke whales, according to new research.
Scientists studying whales in Canada have challenged previous theories that lampreys attach to whales purely to "hitch a ride".
Photographs show bloody lesions after lampreys detached from whale hosts, indicating feeding.
Sea lampreys are parasitic fish that feed on others' blood, attaching to the skin with a suction-cup like mouth.
Sea lampreys (Petromyzon marinus) are known to feed on a wide variety of fish using a funnel-like mouth filled with teeth and a razor-like tongue.
In the past lamprey teeth-marks have been identified on whale and porpoise bodies.
Sea lampreys have also been photographed attached to Pacific humpback and North Atlantic right whales.
Based on these rare glimpses, certain scientists theorised that sea lampreys feed on cetaceans, but it was not possible from this evidence to say conclusively that they were drawing blood.
Others in the scientific community argued that P. marinus could merely be using cetaceans for transport, biting into their flesh in order to travel long distances.
However, during studies in the St Lawrence estuary, where the Great Lakes enter the Atlantic Ocean in eastern Canada, researchers resolved the debate.
The long-term study of minke whales in the area provided the first ongoing observations of sea lamprey and whale interaction.
Their findings were published in the Journal of Fish Biology.
"We and others had long had reason to believe that the lampreys were feeding," said Owen Nichols, Director of the Marine Fisheries Initiative at the Provincetown Center for Coastal Studies in Massachusetts, US.
"The high frequency of minke whale observations coupled with their behaviour in the estuary, frequent surfacings with much of their bodies visible, made these observations possible."
Ursula Tscherter was responsible for the fieldwork during which the research team photographed whales before, during and after lamprey attachment.
"Little is known about lamprey fish on cetaceans especially on minke whales," said Ms Tscherter.
"To document the presence of lamprey fish on individually identified minke whales, which use the St Lawrence estuary as a summer feeding ground, helps to put the topic into a broader context."
The images of bloody lesions on the whales provided the first evidence that the parasites fed on cetacean blood.
"To our knowledge these are the first in-situ observations of such behaviour during which one can convincingly state that lampreys attached to whales are rasping through the skin and feeding rather than just 'hanging on for the ride'," explained Mr Nichols.
Sometimes dubbed the "vampire fish", P. marinus was accidentally introduced to North America's Great Lakes in the 1800s.
Like salmon, sea lampreys are "anadromous", meaning they are born in fresh water, migrate to the sea for their adult life and eventually return to freshwater to spawn and die.
Efforts are now being made to better understand the species in order to control the invasive population that threatens native fish species.
http://news.bbc.co.uk/earth/hi/earth_news/newsid_9281000/9281424.stm
By Ella Davies
Earth News reporter
http://www.blogger.com/post-create.g?blogID=4348728589329576621
Showing posts with label sea lamprey. Show all posts
Showing posts with label sea lamprey. Show all posts
Tuesday, January 4, 2011
Blood-sucking fish feed on whales
Blood-sucking sea lampreys feed on prey as big as minke whales, according to new research.
Scientists studying whales in Canada have challenged previous theories that lampreys attach to whales purely to "hitch a ride".
Photographs show bloody lesions after lampreys detached from whale hosts, indicating feeding.
Sea lampreys are parasitic fish that feed on others' blood, attaching to the skin with a suction-cup like mouth.
Sea lampreys (Petromyzon marinus) are known to feed on a wide variety of fish using a funnel-like mouth filled with teeth and a razor-like tongue.
In the past lamprey teeth-marks have been identified on whale and porpoise bodies.
Sea lampreys have also been photographed attached to Pacific humpback and North Atlantic right whales.
Based on these rare glimpses, certain scientists theorised that sea lampreys feed on cetaceans, but it was not possible from this evidence to say conclusively that they were drawing blood.
Others in the scientific community argued that P. marinus could merely be using cetaceans for transport, biting into their flesh in order to travel long distances.
However, during studies in the St Lawrence estuary, where the Great Lakes enter the Atlantic Ocean in eastern Canada, researchers resolved the debate.
The long-term study of minke whales in the area provided the first ongoing observations of sea lamprey and whale interaction.
Their findings were published in the Journal of Fish Biology.
"We and others had long had reason to believe that the lampreys were feeding," said Owen Nichols, Director of the Marine Fisheries Initiative at the Provincetown Center for Coastal Studies in Massachusetts, US.
"The high frequency of minke whale observations coupled with their behaviour in the estuary, frequent surfacings with much of their bodies visible, made these observations possible."
Ursula Tscherter was responsible for the fieldwork during which the research team photographed whales before, during and after lamprey attachment.
"Little is known about lamprey fish on cetaceans especially on minke whales," said Ms Tscherter.
"To document the presence of lamprey fish on individually identified minke whales, which use the St Lawrence estuary as a summer feeding ground, helps to put the topic into a broader context."
The images of bloody lesions on the whales provided the first evidence that the parasites fed on cetacean blood.
"To our knowledge these are the first in-situ observations of such behaviour during which one can convincingly state that lampreys attached to whales are rasping through the skin and feeding rather than just 'hanging on for the ride'," explained Mr Nichols.
Sometimes dubbed the "vampire fish", P. marinus was accidentally introduced to North America's Great Lakes in the 1800s.
Like salmon, sea lampreys are "anadromous", meaning they are born in fresh water, migrate to the sea for their adult life and eventually return to freshwater to spawn and die.
Efforts are now being made to better understand the species in order to control the invasive population that threatens native fish species.
http://news.bbc.co.uk/earth/hi/earth_news/newsid_9281000/9281424.stm
By Ella Davies
Earth News reporter
http://www.blogger.com/post-create.g?blogID=4348728589329576621
Scientists studying whales in Canada have challenged previous theories that lampreys attach to whales purely to "hitch a ride".
Photographs show bloody lesions after lampreys detached from whale hosts, indicating feeding.
Sea lampreys are parasitic fish that feed on others' blood, attaching to the skin with a suction-cup like mouth.
Sea lampreys (Petromyzon marinus) are known to feed on a wide variety of fish using a funnel-like mouth filled with teeth and a razor-like tongue.
In the past lamprey teeth-marks have been identified on whale and porpoise bodies.
Sea lampreys have also been photographed attached to Pacific humpback and North Atlantic right whales.
Based on these rare glimpses, certain scientists theorised that sea lampreys feed on cetaceans, but it was not possible from this evidence to say conclusively that they were drawing blood.
Others in the scientific community argued that P. marinus could merely be using cetaceans for transport, biting into their flesh in order to travel long distances.
However, during studies in the St Lawrence estuary, where the Great Lakes enter the Atlantic Ocean in eastern Canada, researchers resolved the debate.
The long-term study of minke whales in the area provided the first ongoing observations of sea lamprey and whale interaction.
Their findings were published in the Journal of Fish Biology.
"We and others had long had reason to believe that the lampreys were feeding," said Owen Nichols, Director of the Marine Fisheries Initiative at the Provincetown Center for Coastal Studies in Massachusetts, US.
"The high frequency of minke whale observations coupled with their behaviour in the estuary, frequent surfacings with much of their bodies visible, made these observations possible."
Ursula Tscherter was responsible for the fieldwork during which the research team photographed whales before, during and after lamprey attachment.
"Little is known about lamprey fish on cetaceans especially on minke whales," said Ms Tscherter.
"To document the presence of lamprey fish on individually identified minke whales, which use the St Lawrence estuary as a summer feeding ground, helps to put the topic into a broader context."
The images of bloody lesions on the whales provided the first evidence that the parasites fed on cetacean blood.
"To our knowledge these are the first in-situ observations of such behaviour during which one can convincingly state that lampreys attached to whales are rasping through the skin and feeding rather than just 'hanging on for the ride'," explained Mr Nichols.
Sometimes dubbed the "vampire fish", P. marinus was accidentally introduced to North America's Great Lakes in the 1800s.
Like salmon, sea lampreys are "anadromous", meaning they are born in fresh water, migrate to the sea for their adult life and eventually return to freshwater to spawn and die.
Efforts are now being made to better understand the species in order to control the invasive population that threatens native fish species.
http://news.bbc.co.uk/earth/hi/earth_news/newsid_9281000/9281424.stm
By Ella Davies
Earth News reporter
http://www.blogger.com/post-create.g?blogID=4348728589329576621
Monday, June 29, 2009
Rare fish 'proves water quality'
The discovery of a rare blood-sucking fish in the River Wear is proof of high water quality, conservationists said.Seven adult sea lampreys, which have toothed, funnel-like sucking mouths, have been found in the river near Chester-le-Street, County Durham.
Only three species of lampreys remain in Britain, and they are protected under European law.
The Environment Agency said the creatures only breed in water which is very clean.
So far the agency has identified twelve spawning sites, known as redds.
Fisheries officer Paul Frear said: "We were thrilled to discover lampreys back in the River Wear, as these rare blood-suckers show us that the water quality in the river is very high.
"Lampreys are extremely selective with their spawning sites and will only nest where the water quality is optimal."
Scientists are continuing to search for more lampreys, and anyone who spots one is asked to report the sighting to the Environment Agency.
http://news.bbc.co.uk/1/hi/england/wear/8122999.stm
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