Lobsters Turn to Cannabalism

An adult lobster eats a tethered juvenile lobster (as indicated by the arrows) in these handout pictures taken from an infrared camera on the ocean floor near Maine. Graduate student Noah Oppenheim, has been documenting the phenomenon using a special infrared camera that allows him to observe a juvenile lobster tethered with a rope to a spot on the ocean floor. During the daytime, it is fish that typically feed on the tethered juvenile lobsters, but at night the researchers were stunned to see that most of the attacks on the small lobsters were by their larger brethren. REUTERS/Gregory Oppenheim/Handout

An adult lobster eats a tethered juvenile lobster (as indicated by the arrows) in these handout pictures taken from an infrared camera on the ocean floor near Maine. Graduate student Noah Oppenheim, has been documenting the phenomenon using a special infrared camera that allows him to observe a juvenile lobster tethered with a rope to a spot on the ocean floor. During the daytime, it is fish that typically feed on the tethered juvenile lobsters, but at night the researchers were stunned to see that most of the attacks on the small lobsters were by their larger brethren. REUTERS/Gregory Oppenheim/Handout

Off the coast of the USA, big lobsters have started eating their little brethren in a move never before recorded in the wild.

This is a fascinating case study of population change in the face of climate change and overfishing. And this time it’s about a population that is not only surviving – it’s changing behaviour too.

Warming waters in the Gulf of Maine and decreased predators due to overfishing have led to a huge population increase in recent years. A record 104 million pounds (45 million kilograms) were caught in 2011, compared with 23 million pounds in 1981. 2012 is expected to be even higher.

Lobsters are no stranger to aggressive interaction: they will attack each other when confined in a small space. But now encounters with each other in the Gulf of Maine are becoming so frequent that a predator-prey interaction has come about.

In a study by researchers from the University of Maine, they found that fish were the main lobster predator during the day. But the populations of cod, halibut and other groundfish that feed on lobsters has declined due to overfishing, and in a surprising find, 90% of predation on juvenile lobsters at night was due to older, bigger lobsters feeding on their younger brethren.

The Maine researchers believe this is the first time such behaviour has been visually documented in the wild, although Canadian researchers have also recently found evidence of cannabilism by examining lobster stomach content.

In an interesting contrast, warming waters have led to more disease and lower populations in Long Island Sound and southern New England. The increased abundance (and thus lower cost) of Maine lobster has also led to tensions with Canadian fishermen.

To read the original article from Reuters, click here.

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2 thoughts on “Lobsters Turn to Cannabalism

  1. Wow, that’s insane. Thank you for posting this!

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