Subscription Services: Subscribe | Change | Unsubscribe | RSS
Advertising Media Kit: Introduction | Rates | Testimonial | Contact
Miscellaneous: Reference Desk | Sitemap
Scientists Seek How Crabs Find Their Way Back Home; 'They Seem to Sense the Need to Get Back'
print this print      Bookmark and Share   RSS 2.0 feed

LEWES, Delaware -- Swallows return to Capistrano, and buzzards to Ohio. In the Chesapeake and Delaware bays, it's the tasty and feisty blue crabs, and researchers are still trying to find out how.

"What we know points up everything we still don't understand about what triggers what behavior," said Elizabeth W. North, a researcher at the University of Maryland Center for Environmental Studies at Horn Point, Md. "Somehow, they seem to sense the need to get back to the bays."

Larval crabs are spawned in estuaries such as the Chesapeake or Delaware bays spend weeks in saltier ocean waters before returning to live out their lives. North is leading a project studying how currents, salinity and nutrient affect the movement of billions of drifting blue crab larvae.

Some researchers suspect the larvae floating along in ocean currents are attracted by less salty bay water.

"The hypothesis is that the crab larvae smell the lower salinity in the bay, then ride a high tide in from the ocean," said Michael Roman, who directs the Horn Point lab near Cambridge. "There is a change in behavior when they get close to the bay that we need to understand."

North's team, comprising researchers from Maryland and Delaware, spent last week at sea aboard the University of Delaware's new $19.4 million research vessel, the Hugh R. Sharp. The team spent six-days at the mouth of Chesapeake Bay and two days about 10 miles offshore from the University of Delaware's marine studies center in Lewes, where the ship is based.

The researchers used an elaborate nylon net to catch the nearly invisible crab larvae at various depths and an underwater device resembling an airplane wing to collect data on the number of larvae at various depths.

Analyzing the samples could take a year, said University of Delaware researcher Ana Dittel, an expert in larvae ecology,

"You can't really see much to catalog until you get the sample under a microscope," she said.

Views expressed in this article do not necessarily reflect those of UnderwaterTimes.com, its staff or its advertisers.

Reader Comments

No comments have been submitted. Why not be the first to tell us your thoughts? cloud add your comment


bottom_left
bottom_right
Privacy Policy     © Copyright 2017 UnderwaterTimes.com. All rights reserved