Exam 3 Name:

EEB 200 Biology of Fishes Spring 1997

1. (8 points) Provide any of the following 4 definitions:

ecology

hermatypic

iteroparity

migration

phenotypic plasticity

reproductive effort

school

shoal

2. (6 points) The predation sequence can be divided into 3 stages: encounter prey, attack prey and capture prey.

1) Indicate how prey schooling might confer protection from predators at each stage

2) Is schooling likely to provide protection at each of these stages, or does it provide a benefit primarily at one of these stages?

3. (3 points) Aside from countering predation and enhancing feeding opportunities, are there other possible benefits to schooling? If so, explain what it might be and indicate whether it is likely to be a significant benefit.

4. (7 points) Migration behaviors can be categorized in a number of ways. Migrations between habitats of different salinities is called ___________. Within this category, migration into fresh waters from the sea to reproduce is called ___________. An example of a fish that performs this behavior is __________. The reverse pattern, migration from fresh waters into the sea to reproduce, is called __________. A fish that performs this behavior is ____________. Migrations between different salinities that do NOT involve spawning migrations are called _________. Finally, there are migrations that do not involve passage into waters of a different salinity. For instance, migrations that occur wholly within fresh waters are called ___________.

5. (4 points) Some fishes mature quite early in life. List a species or fish group that shows this life history feature. What are advantages and disadvantages of early maturation (advantages+disadvantages should sum to at least 3)?

6. (6 points) For any of the following THREE, match the fish with the reproductive strategy. Indicate whether the following fishes are a) nonguarders b) guarders c) bearers. Some fish groups may do more than one strategy, in which case I would like you to note this for full credit. Provide additional information where you can (i.e. where nest is created, etc.)

Centrarchids

Damselfishes

Elasmobranchs

Esocids

Salmonids

Sticklebacks

7. (6 points) The American shad shows latitudinal variation in the degree of semelparity. Which populations are entirely semelparous, low latitude (southern), or high-latitude (northern)? Several hypotheses have been offered to explain the relative evolutionary advantages of semelparity, including: 1) the rate of juvenile mortality; 2) interannual variance in the rate of juvenile mortality. For each, indicate whether a low level or high level of each parameter would favor semelparity. It might be a good idea to define semelparity, if you are confusing it with its opposite I might be able to give partial credit.

8. (4 points) If one wants to graph fecundity against length and get a straight line, we must scale each axis (choose one: linearly / logarithmically / sinusoidally). What is a typical value for the slope of this line and why?

9. (4 points) In this graph, a histogram of GSI is presented for males and females, for different species. Provide the formula for GSI. The dark bars are which sex? Explain why there is this sex difference.

10. (4 points) The video program that we saw, CNN's "The Killing Tide", described the Alaskan halibut fishery as exemplary of an open access fishery in which regulation is about to be overhauled. 1) Describe the current state of the fishery; 2) problems with the fishery from the point of view of both the fishers and the consumer; 3) new models for fishery regulation that are likely to be employed.

11. (4 points) List three types of human activities that are affecting marshes, and explain why this is having a major effect on marine fisheries in such areas as the Gulf of Mexico

12. (6 points) Ecological study may be focused on one of several levels, or some combination of levels, in a natural hierarchy, from individuals to populations to communities. List properties (attributes) that are studied by ecologists at each level.

Individuals:

Populations:

Communities:

13. (3 points) Characteristically, changes in stream order are associated with changes in a variety of abiotic and biotic factors. In words (or simple graphs), describe how the following change with stream order (*put stream order on the x axis please and be clear which end of the axis is low-order):

Daily temperature range

Light

Prey diversity

14. (2 points) In what region of the US is stream fish diversity highest, and in what region is it lowest?

15. (4 points) Your textbook on fish biology comments that attempts to increase populations of salmon by eliminating fish-eating birds over streams have failed because the salmon are less successful at sea. Discuss how the abundance and growth rates of salmon are likely to change when the predators are removed, and how this might affect their survival at sea.

16. (10 points) A study by Minckley and Meffe tested the effects of floods on fish assemblages in streams in the American southwest. They measured flood magnitude and community characteristics after the flood, focusing on differing responses of exotic and native fish species. Complete the following two graphs; on the lower graph, note that both native and introduced species should be graphed. Why might there have been these relationships? What more should be done to confirm this?

17. (3 points) List one abiotic, one biotic, and one anthropogenic factor that is influencing coral reef communities (as a whole, not just fishes).

18. (2 points) List at least two factors (biotic or abiotic) that change, and describe how they change, as one proceeds along a transect from the forereef across the reef crest to the backreef.

19. (5 points) This graph of chaetodontid distributions along a transect across the Great Barrier Reef system has been used to argue that interspecific competition has been an important process structuring reef fish communities. Elaborate on why this evidence was viewed in this way, and discuss what further work would be necessary to test this idea further.

20. (9 points) These two graphs report the results of an experiment in which all damselfish were removed from reefs. The left-hand graph shows recovery of numbers over time, while the right-hand graph shows the abundance of recruits relative to unmanipulated controls.

1) What is regulating the abundance of this species?

2) Is this result consistent with the lottery model?

3) How would the results of this experiment help to explain the high diversity of reef fishes?