B. Biological Pollutants

Question 1

What is the definition of an Alien Invasive Species?

Answer 1

A NON-NATIVE species that is

INTRODUCED to an ECOSYSTEM

(deliberately or accidentally) by HUMAN ACTIVITY

and becomes ESTABLISHED there

and THREATENS native biodiversity.

Question 2

a. ) Provide two examples of an aquatic invasive species
b. ) Their Introduction pathways
c. ) Their impacts on their recipient ecosystems

Answer 2

a.) Sea Lamprey (into Lake Ontario, 1830s)

 Nile Perch (into Lake Victoria, 1950s)

b.) Through man-made shipping canals

 Deliberate release for economic reasons (fisheries)

c.) Predates comercially important fish species; if uncontrolled, economic costs could be > US $500 million p.a.

Outcompeted native species causing >200 species to go extinct (many endemic)

Question 3

Name 5 Integrated Pest Management techniques being used to control the sea lamprey in the Great Lakes

Answer 3

1. Mechanical Control: Traps + Barriers (low-head velocity barriers) at weirs, waterfalls etc to prevent upstream migration for spawning
2. Chemical Control: Lampricides (TFM in nursery tributaries)
3. Biological Control: Releasing sterilized males & baiting traps with pheremones (past measures)

Question 4

What were the negative impacts of the introduction of sea lamprey into the Great Lakes?

Answer 4

1. Predating over 100 million pounds of commercially valuable fish each year (estimated).
2. Had no natural predators in the Great Lakes.

Question 5

What was the Introduction Pathway for the Sea Lamprey into the Great lakes?

Answer 5

1. Entered Lake Ontario from the Atlantic Ocean through man-made shipping canals in the 1830s.
2. Niagra Falls acted as a natural barrier preventing further spread.
3. However the deepening of the Welland Canal in 1919 allow the sea lamprey to spread further into the other Great Lakes (Eerie, Huron, Michigan and Superior).