Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Crustacean brawls caught on camera

12.02.2002


Underwater video reveals lobsters behaving badly.


Going to pot: scientists are re-assessing their lobster traps
© Winsor H. Watson, III


Kitchen confidential: surveillance cameras crack down on lobster trap layabouts



A lobster-pot is more like a Wild West saloon than a cunningly laid snare. Lobsters show up for food and a fight, and only the unlucky few get reeled in, underwater video footage is revealing.

Camera recordings show that lobster traps catch a mere 6% of the animals that enter them. The result suggests that lobsters’ rowdy behaviour could be confusing attempts to count and size them, and so to manage the fishery1.


"Predicting the future of the population is difficult," says Stanley Cobb, who studies lobsters at the University of Rhode Island in Kingston. "Traps may not be sampling all parts of the population." Egg-bearing females, for example, seem to avoid them, says Cobb.

Lobster numbers are usually estimated from the catches of experimental traps. To gauge


The traps soon attracted a crowd of brawling crustaceans. "They hate each other," says Watson. "They compete outside the trap for the next opportunity to enter, and occupants fight off those trying to come in."

Traps have a ’kitchen’ where bait is kept. This leads to two ’parlours’ where lobsters are supposedly held. They also have emergency exits to let undersized animals out.

Lobsters, however, don’t play fair: "75% of them went right back out the entrance," says Watson. The few that were caught tended to be larger specimens that could fight off intruders, and were interrupted mid-meal. "We call it the restaurant hypothesis," Watson says.

What’s the catch?

"A lot of lobstermen feel that traps are really feeding stations," says Cobb. New England’s lobster fishery is in good health - perhaps, says Cobb, because of all the bait that fishermen put out. Lobster catches worth about $200 million are landed each year in Maine alone.

But researchers are not sure how long the good times can go on. "We catch about 90% of lobsters bigger than the legal size limit. I’m concerned we’re fishing too heavily," says Watson. Catches are beginning to decline in the southern area of the fishery, and there are signs that disease is damaging the crustaceans.

Researchers would like to be able to read any warning signs, so that they can move to avert possible crashes, rather than have to repair a shattered fishery. To do this, they may need new ways of counting lobsters - one possibility Watson suggests is a trap that can catch multiple lobsters by moving them away from the entrance, "like a maze".


References

  1. Jury, S. H., Howell, H., O’Gradt, D. F. & Watson, W. H. III Lobster trap video: in situ surveillance of the behaviour of Homarus americanus in and around traps. Marine and Freshwater Research, 52, 1125 - 1132 , (2001).

    JOHN WHITFIELD | © Nature News Service

More articles from Life Sciences:

nachricht Topologische Quantenchemie
21.07.2017 | Max-Planck-Institut für Chemische Physik fester Stoffe

nachricht Topological Quantum Chemistry
21.07.2017 | Max-Planck-Institut für Chemische Physik fester Stoffe

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

Ultrathin device harvests electricity from human motion

24.07.2017 | Power and Electrical Engineering

Scientists announce the quest for high-index materials

24.07.2017 | Materials Sciences

ADIR Project: Lasers Recover Valuable Materials

24.07.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>