Asian Shore Crab and European Green Crab HabitatAmy Darbyshire | Conor Clifford | Quinn Coughlin | Stephanos Mitrokostas | Augusta Davis

Asian Shore Crab (Hemigrapsus sanguineus) on the left and European Green Crab (Carcinus maenas) on the right.

Hemigrapsus sanguineus Carcinus maenas

Question and HypothesisResearch Question:

“How do the hydrophysical properties of the Sandwich Town Beach Estuary affect the distribution of Hemigrapsus sanguineus and Carcinus maenas?”

Hypothesis:

Based off of some prior research -- and consultation with Dr. Pete -- we suspect that the Asian Shore Crab (H. sanguineus) will be more common in the turbulent and cooler outer beach waters rather than in the estuary, whereas the European Green Crab (C. maenas) will likely be found in calmer estuary waters, but not necessarily in warmer ones.

Materials and MethodMaterials:• 2 nets and 2 pails (to catch and contain crabs)• ham (bait)• 3 pieces of string, 2 one meter long and 1 five

meter long (one to assist in measuring the quadrats, one to tie the bait, and the third to tie the water bottle to measure current speed)

• an empty water bottle• 2 poles (to measure out quadrats)• 2 pairs of waders• iPhone (for taking pictures, stopwatch and a gps)

Materials and MethodMethods:Catching the crabs:• Tie a pole to each end of the one meter long

piece of string and place the poles in the water so the string is stretched out, measuring one meter and record GPS coordinates of the quadrat.

• Tie the bait to the other meter long piece of string and place it in the water.

• Use the nets to catch the crabs as they attack the bait.

• Fill the two pails with water and keep the Asian Shore crabs (H. sanguineus) in one bucket and the European Green crabs (C. maenas) in the other.

Materials and MethodMethods:Current Speed:• Tie the five meter long string to the water bottle

and release it into the water.• Use a stopwatch to time how long it takes to

travel the five meters.• Divide five meters by the amount of seconds it

took the bottle to travel five meters to find current speed.

Temperature• Place thermometer in water at the different sites

and record temperature in oC.• We used 2 different thermometers to record an

accurate temperature

Raw DataTemperature, Current Speed and Number of Shore Crabs at Sandwich Beach Estuary

Processed Data

Processed Data (cont.)

Conclusion The number of crabs that live in a certain area is affected by

current speed and water temperature. As our data shows, the faster the current and the colder the water, the less likely crabs will live in an area. It is also apparent that C. Maenas (European Green Crabs) are far more common than H. sanguineus (Asian Shore Crabs). While C. maenas Crabs were more common, H. sanguineus Crabs were found in colder water with faster current speeds than the water where C. maenas Crabs were found though to little data of H. sanguineus Crabs was collected to draw a complete conclusion of the habitat of the H. sanguineus. In conclusion, C. maenas are very common and tend to live in warmer water (around 17 degrees celsius), and with slower current speeds (below 0.45 meters per second).

Evaluation Limitations / Advantages

Why is this a problem / benefit?

How did this affect the lab?

The amount of time spent at each area.

We spent a different amount of time at each location. This may impact the opportunities to catch crabs.

It is difficult to determine whether the hydro-physical properties of the Sandwich Town Beach Estuary impacted the number of crabs found or whether it was the amount of time spent at each station.

How effectively the group worked together.

Good communication and equal effort by team members.

Efficient completion of the task.We were also able to collect data in an orderly manner and make sure it was thorough and accurate.

Sharing of knowledge and personal ability.

The team members had different strengths and abilities.

Sharing knowledge between ourselves; our strengths and weaknesses varied and we were able to learn different things from each other.

Pictures!

Online Images Bibliography"Hemigrapsus Sanguineus." Wikipedia. Wikimedia Foundation, 10 June 2013.

Web. 15 Oct. 2013.

Bortolus, Alejandro. "Carcinus Maenas | The Exotics Guide." The Exotics Guide. N.p., n.d. Web. 15 Oct. 2013.