Possible Clues:

• Reticent type turns up in abnormal clothing
• Oyster relative
• Shellfish 100 pounds a thousand
• Geoduck, for one
• Learner in academic stream is secretive type
• Paella ingredient, perhaps
• Introduces artists coming back over American city with shy person, informally speaking
• Littleneck, e.g
• Place for steamers
• Quahog, e.g