Exotic Species

•Aquaculture

•Sport

•Ornamental

•Improvement of wild stocks

–New food fisheries

–Fill a vacant niche

–Forage for predators

–Restoration of fisheries

–Establish a wild stock

•

•Accidental

–Escape or release from aquaria and bait bucket

–Diffusion through waterway

–Introduced with other species

–Live transportation for consumption

–Ballast water of ships

–Shipping water (zooplankton)

–Packing material (seaweed)

•Control of unwanted species

–Aquatic vegetation

–Mosquitoes

–Snails

–Blooms of phytoplankton

–Other fish (usually exotic)

–

•

Reasons for which species have been introduced:

Source: Welcomme 1988


	There are almost as many ways for introductions to occur as there are introductions. But here is a list of the most well-known and documented. I found one example of shipping water very interesting. Several years ago 3000 Pacific oysters were shipped from California to Woods Hole. The shipment had 2 certificates stating the oysters were parasite and disease free. That was all well and good but only 10% of the shipment was checked which I believe is standard. After arriving at Woods Hole, the oysters were washed and the water saved. There was a total of 29 species of algae, diatoms, protozoans, and invertebrates detected in the water the oysters were shipped in.