Wednesday, August 19, 2015

2015 Project Limulus Horseshoe Crab Spawning Survey Summary for Guilford,CT

Greetings to all MAS supporters and Project Limulus volunteers,

Here is my annual summary of the 2015 Project Limulus Survey Sessions. Our horseshoe crab surveys began on May 1st and ended on June 18th.

We weregiven 150 tags by the Sacred Heart Project Limulus professors. We were easily able to use them all and we could have used more but they were not available. All of the crabs tagged this year were found in Indian Cove or at Cha
ffinch Island Park.

The Project Limulus volunteers surveyed the two beaches at Indian Cove in Guilford a total of 14 times. The surveys are conducted around the time of the full moon and the new moon and always begin at high tide. The standardized surveys are always done in Indian Cove but tagging can be done at any of the Guilford beaches.

The total number of crabs counted during the standardized surveys was 108. Last year the total counted was 174 but that number included one night when we counted 97 crabs! Finding that many in one night was highly unusual and I believe it inflated our average number of crabs per survey found that year. The average number of crabs found per survey for the last 6 years is as follows:

2010 - 6.5 crabs per survey
2011- 7.1 crabs per survey
2012 - 7.8 crabs per survey
2013 - 3.06 crabs per survey
2014 - 10.24 crabs per survey
2015 - 7.1 crabs per survey

My unscientific guess is that storms Irene and Sandy had something to do with the low average number of crabs found in 2013. With the exception of 2013 and 2014, the horseshoe crab population in Indian Cove seems to be fairly stable.

Recaptures are crabs which have already been tagged. We record their tag numbers in our data. Our recapture totals have been declining over the past 4 years but we don’t know why. This year we only found 20. If you find a horseshoe crab and it has a tag, please record the I.D. number and call the phone number on the tag to report it. Please make note of the date and where you found it. Dead crabs with tags are important to report as well.


I am sincerely grateful to all of the people who were able to help this year. I am fortunate to have such an awesome group of volunteers!

Best regards, 
Judy Knowles