OCEAN 320 Study Guide - Quiz Guide: Pelagic Fish, Overfishing, Predatory Fish
Unit 3 Study Guide
Unit 3A:
Why might the Blue Whale still be around? What is different about its survival strategy. How
might the Blue Whales diet give it an advantage over Megladon?
A: Blue whales do not rely do heavily on an abundance of large prey; they have adapted
to consume a greater amount of smaller trophic levels, such as pelagic fish and even krill.
The Megladon would have required large prey and large quantities to sustain itself.
Earth’s fish populations probably could not sustain such large animals, especially not
numerous Megladons.
So why talk about history, archeology and anthropology in a ocean course?
A: It is important to consider all the factors that could have exerted change in the ocean
over time; even a small human population greatly affects the overall productivity and
geological atmosphere of the ocean. We must consider when oceans began changing and
why; it is important to look at the overall impact humans have had on the ocean over the
course of our existence to understand what the future may hold.
Unit 3B:
How did the historical "Law of the Sea" play a role in bringing fisheries to the state of collapse?
A: In making the ocean “fair game,” the “Law of the Sea” effectively allowed
overfishing, which in turn caused population declines and eventually hurt fisheries in the
long run. To compensate, fleets much now go well beyond their reaches to catch
considerable quantities of fish, and often must take younger and immature fish to keep up
with supply and demand.
What is the other really big reason that the oceans have been overfished?
A: Oceans have also been overfished because of “fishing down,” which occurs when the
fish at the top of the food chain (tuna, swordfish) become rare and fishermen overfish the
lower trophic levels to compensate.
Where is an overfishing "hotspot" near North America?
A: Nova Scotia/Maine is a hotspot for overfishing in North America.
Do you understand the concept of "fishing down the food chain"?
A: Yes, fishing down the food chain occurs when fishermen have little of the predator
fish left to exploit, so they instead catch enormous amounts of pelagic fish to keep up
with demand.
How long does it take, based on the areas studied, to reduce the biomass of previously un-fished
stock by a factor of 10?
find more resources at oneclass.com
find more resources at oneclass.com
