Taxonomy


Phylum: Mollusk
  Class: Gastropod
   Subclass: Prosobranchia
    Order:Archaeogastropoda
        Family: Trichinae
        Genus species:        Cittarium pica

Relevance & Natural History

Cittarium pica (The West Indian Top Shell) are large snails that inhibit shallow rocky  intertidal zone. C. pica are normally seen up to the depth of around ten metes. C. pica has relatives that include other snails, slugs and limpets. It is also referred to as the West Indian Whelk in the Caribbean. There is a long natural history for this particular species on Bermuda.  C. picas are commonly found throughout the Caribbean, ranging from the Bahamas to the central coast of South America. Bermuda is the furthest northern location that this particular species is found.

 In Bermuda the earliest indications and speculations include that Bermuda was discovered around the early 1500’s but was not officially settled until the year 1612 in the name of King James I of England.  C. picas were extremely abundant and served as a staple of the Bermudian diet. C . pica also served as a source of bait during colonization and subsequent generations.

C. pica has many natural predators such as other snails and various bird species as well as any number of fish on the shallow intertidal. C. pica has many natural predators such as other snails and various bird species as well as any number of fish In Bermuda however they were ultimately driven to extinction by over harvesting by humans during the early 19^th century.   In present day harvesting continues to be common practice among coastal communities where C. picas flourish although strict regulations permit seasonal harvesting. The human influence on pushing C. pica into extinction on Bermuda is one example of how there must some balance between humans and nature. The death of the West Indian Top shell allows for their empty shells to provide a home for hermit crabs. After C. pica extinction in Bermuda, the purple-clawed hermit crab (Coenobita clypeatus) began to die off almost instantly. Scientist speculate it was due to the lack of whelk shells apparently which were used as housing for these hermit crabs. The effects of overharvesting prompted tremendous concern among activists. The effects overharvesting had on the convoluted food web in Bermuda. The Bermuda government instituted protection regulations to eliminate illegal removal of C. pica dead or alive from the island, it is now illegal to harvest them in any fashion.