The Quahog

Chemistry

Quahog

● the southern quahog seems to prefer the oceanic water.

● they like to gather near inlets and in offshore habitats

● grows rapidly under highly saline conditions

Under what range of salinities do Quahogs thrive?

● They secrete a calcium-based shell material from an inner structure called the mantle

● Create shell around themselves for protection

● Shell grows as they mature● Thier shell can reveal many clues about

thier age, diet, or the composition of the water they live in

What is their shell made of and how do they produce it?

What effect does carbon in the atmosphere have on shell formation?

anterior side

umbo

dorsal side

hinge

posterior side

clam is laying on its right valve

left valve

Exterior of Clam

Danielle Donadio

Lab Bench #4

ventral side

mantle

gills

adductor muscles

foot

Danielle

Donadio

excurrent siphon

incurrentsiphon

Interior of ClamLab Bench #4

Deep Interior of Clamintestine

mouth/digestive gland

anus

Danie

lle D

onadio

Lab Bench #4

Ecology: What do quahogs eat and what eats them?

● Filter feeders who eat through siphons that they dig into the mud

● Pick up tiny particles of plankton ● Predators include humans and a variety of

crustaceans and fish, including starfish, blue crabs, horseshoe crabs, aquatic snails, skates, and rays

Lab Bench #4

Ecology: Population Density

● lower water quality and higher population density in areas closed to fishing in Narragansett Bay

● causes lower reproduction capability and gonadal cycle as compared to conditional fishing areas

Lab Bench #4

External

hinge

umbo

ventral

dorsal

anteriorposterior

left valve (top)right valve (bottom)

Internal

mantle

foot

gills

adductor muscle

anusmouth

incurrent siphon

excurrent siphon

intestine

Deep Internal

gills

anus

adductor muscle

incurrent siphon

excurrent siphon

mantle

Geology At what range of depths do quahogs thrive?The Mercenaria Mercenaria (a local hard shell clam common called quahogs) can be usually found at a depth of 10 meters. They use their muscular foot to burrow deep into the sediment.

Virginia PellereyElizabeth BlanchetteKatie Goglia

Geology

In what type of substrate (bottom material) are you likely to find quahogs?You are likely to find this kind of shell on mud/sand flats, typically near inlets and in offshore habitats.

Virginia PellereyElizabeth BlanchetteKatie Goglia

Lab Bench 1: External

Hinge

Anterior

DorsalRight Valve (bottom side: not shown)

PosteriorLeft Valve (upper side)

Ventral

Umbo

Julianna RisicaAlly BushLauren RanneyFinnian Duncan

Lab Bench 1: Internal

Foot

Mantle

Gills

Adductor Muscles

Julianna RisicaAlly BushLauren RanneyFinnian Duncan

Lab Bench 1: Internal Continued

Digestive Gland

Intestine

Incurrent Siphon

Julianna RisicaAlly BushLauren RanneyFinnian Duncan

Lab Bench 1: ResearchReproduction of Quahogs ● Spawning Process● Males release sperm through siphons● Females release eggs through siphons● Sperm and Eggs unite and DevelopDiet● filter feeders● suck up water through incurrent siphon and absorb

plankton, bacteria, oxygen● filter water and waste products out of excurrent siphon

Julianna RisicaAlly BushLauren RanneyFinnian Duncan

Lab Bench 1: Research Cont.Anatomy and Physiology● Two shells made of calcium carbonate that the clam secretes● Joint of the shells formed by hinge made up of intermeshing teeth● The overall purpose of the shell: protect the interior of the clam ● Adductor muscles to close the shell to avoid predators or if water conditions are

bad● Muscular foot (contains intestines, digestive glands, and gonads) can reach

outside the shell so that the clam can burrow● Incurrent siphon brings water (oxygen and plankton) into the quahog● Excurrent siphon: where the water (animal’s waste) exits● Mantle: part of animal that forms shell (secretes calcium carbonate)● Gills: obtain oxygen and food (cilia- tiny hair-like structures that creates a current

that moves water through the body)

Julianna RisicaAlly BushLauren RanneyFinnian Duncan

Lab Bench 5: External

Jessica MarabianDeirdre McdonaldHayley Page Umbo

Hinge

Dorsal

Ventral

Anterior

Posterior

right valve (on top shell)

left valve (on bottom shell)

Lab Bench 5: InternalHayley PageJessica MarabianDeirdre McDonald

Anterior Adductor Muscle

Posterior adductor muscle

Excurrent siphon

Incurrentsiphon

mantle

foot

Digestive gland

intestine

mouth

anus

gills (under the foot)

Lab Bench 5: Harvesting MethodsCommercial quahoggers are not allowed to use mechanical methods (dredge or compressor) in the bay. What methods can they use?- Some use considerably large rakes called bullrakes- Commercial businesses go out to the shoreline on single-handed boats- Many work full time on small-skiffs

Are there size limits or seasonal limits? If so what are they?- Yes there are size limits-minimum size: 1 inch hinge width

What are conditional areas?- The restrictions depend on what state one were to quahog- One can only quahog from sunrises to sunset- A licence is required-In Rhode Island the management areas include: Potter, Point Judith, Ningret, Quonochontaug, Winnipuag, Ponds, Greenwich Bay, Bristol Translplant, etc.

Bullrake

Lab Bench 6: Economics

Four Different Types of Quahogs: Kieran Maynard● Little Neck- Smallest● Cherry Stone- Little Larger● Top Neck- Bigger than the Cherry Stone, also labeled count neck

clams● Quahog- Biggest, also called chowder clams

Landing Numbers: ● Quahogs still in abundance● Reduced fishing permits in areas

Economics: Zach and Kieran

Prices of Quahogs:● Quahogs cost $2.00 per pound with 2-3

quahogs making a pound● Quahogs bought in restaurants can be $6-25

External View: Joe Abilheira

Internal View: Joe Abilheira

Deep Internal View: Joe Abilheira