Transcript The Quahog
The Quahog Quahog Chemistry Under what range of salinities do Quahogs thrive? ● 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 What is their shell made of and how do they produce it? ● 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 What effect does carbon in the atmosphere have on shell formation? Exterior of Clam Lab Bench #4 clam is laying on its right valve anterior side umbo dorsal side left valve ventral side hinge posterior side Interior of Clam mantle Lab Bench #4 adductor muscles foot excurrent siphon gills incurrent siphon Deep Interior of Clam Lab Bench #4 anus intestine mouth/ digestive gland Ecology: What do quahogs eat and what eats them? Lab Bench #4 ● 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 Ecology: Population Density Lab Bench #4 ● 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 External ventral right valve (bottom) left valve (top) anterior posterior umbo hinge dorsal Internal gills anus mouth excurrent siphon foot adductor muscle mantle intestine incurrent siphon Deep Internal gills excurrent siphon anus mantle adductor muscle incurrent siphon 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 Pellerey Elizabeth Blanchette Katie 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 Pellerey Elizabeth Blanchette Katie Goglia Julianna Risica Ally Bush Lauren Ranney Finnian Duncan Lab Bench 1: External Hinge Posterior Anterior Left Valve (upper side) Dorsal Right Valve (bottom side: not shown) Ventral Umbo Julianna Risica Ally Bush Lauren Ranney Finnian Duncan Lab Bench 1: Internal Foot Gills Mantle Adductor Muscles Lab Bench 1: Internal Continued Digestive Gland Intestine Incurrent Siphon Julianna Risica Ally Bush Lauren Ranney Finnian Duncan Lab Bench 1: Research Julianna Risica Ally Bush Lauren Ranney Finnian Duncan Reproduction of Quahogs ● Spawning Process ● Males release sperm through siphons ● Females release eggs through siphons ● Sperm and Eggs unite and Develop Diet ● filter feeders ● suck up water through incurrent siphon and absorb plankton, bacteria, oxygen ● filter water and waste products out of excurrent siphon Lab Bench 1: Research Cont. Julianna Risica Ally Bush Lauren Ranney Finnian Duncan 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) Lab Bench 5: External Dorsal Hinge Jessica Marabian Deirdre Mcdonald Hayley Page Umbo right valve (on top shell) Posterior Anterior left valve (on bottom shell) Ventral Lab Bench 5: Internal Hayley Page Jessica Marabian Deirdre McDonald Anterior Adductor Muscle Digestive gland mouth Posterior adductor muscle anus Excurrent siphon Incurrent siphon intestine foot gills (under the foot) mantle Lab Bench 5: Harvesting Methods Commercial quahoggers are not allowed to use mechanical methods (dredge or compressor) in Bullrake 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. 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