Fisheries Science Discussion Questions from Readings

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Fisheries Science Study Guide

MSCI 458 - R. Young, Coastal Carolina University

EXAM

Since much of our material from the year has built upon itself, there will obviously be a comprehensive nature to your understanding of our material since the last test, but I will be asking exam questions from the exam study questions below. In addition to your notes and our study guide questions directly you to the web for info on the history of US fisheries agencies, the test covers material from chapters 8-14, except 13.

What is the tragedy of the commons?
Who was Spencer Fullerton Baird? What did he start, when, and why? What programs, institutions, and agencies have grown out of what he started? How about Henry Bigelow?
Federal fisheries agencies have undergone many changes over the years. How has the management of freshwater vs. saltwater, and recreational vs. commercial fisheries been shaped by practical realities and politics, and how has this shaped the mission of the main federal fisheries regulatory agencies (NMFS and USFWS), as well as the impacts on the fisheries themselves?
What are limitations of international and inter-state fishery agreements?
Why did INCNAF fail in protecting the George's Bank groundfish fisheries? How does this relate to the Magnuson Act?
What were the major components of the original Magnuson Act and what were some of the issues that precipitated it?
What changes were made in the reauthorization of the Magnuson-Stevens Act (1996)?
For each of these regulations, what are the intended effects and what are the unintended backfires that sometimes occur? Also, think about them and consider whether they would work better in recreational or commercial fisheries.

Minimum size limits
Catch/creel limits (limits on the number of fish you can take in a day)
General Quotas
Limited entry (restricted number of permits)
Individual transferable quotas
Time and area closures
Mesh size restrictions
Bycatch gear restrictions

What is the difference between an output control and an input control? Which is tied to some estimate of the total stock size?
What is the difference between a Eulerian and a Lagrangian spacial distribution model? What are their limitations? Their successes?
What is a boxcar model?
What kind of success has been seen with trying to model the spatial and numerical response of fishers to the fish stock using predator-prey models? Why? Do recreational and commercial fishers respond in the same manner to changes in the fish stock?
What are 3 types of models used to examine the short term distribution patterns of fishers and fishing fleets?
How do ideal free distribution models of the distribution of fishing effort help to explain dramatic overfishing? (versus models that assume random distribution of fish and fishers, which predict effort should drop off earlier as stock size declines)
Ecopath with Ecosim is generally recognized as the leading edge food web or trophic model being used today. Can you explain the basic model, as given in class and on p. 246 of your text? How does this differ from the population models we’ve looked at earlier in the semester? What are some of the important variables that go into the determination of Q_ki and Q_ij?
Since the authors strongly support using multiple models to explore a range of potential outcomes, what are other models to consider? (ex. Loop models, examining dominant pred/prey linkages)
What are 3 causes for stable-state changes in an ecosystem (multiple stable states)? Which have we been more successful in modeling/predicting?
What are 3 categories of parameters in ecological models, and what are 3 broad approaches to parameterizing a model (assigning values to your parameters). How do the categories differ in terms of ease of parameterization?
Starting on p. 306, there is a list of interesting “lessons learned” from doing many models. Read it over.
The final chapter (14) has lots of conceptual approaches to management. They are usually italicized headings all through the chapter. Though you might not have to know each by “name,” you should be able to discuss any of them conceptually.

Test 2

The test will be in 2 parts during class time on Wed (3/28) and Friday (3/30). I will give you more specific info regarding which sections for which day. The material is from lecture, from labs 4-6, and from chapters 1-7 in your text, except for Ch. 4. Focus on the areas we covered in class. Most formulas that you may need, I will give you. The exceptions are anything specifically mentioned below as a formula I expect you to know. More will be added to this study guide before the test.
Lab materials:

Click here to get some of my lecture notes. This does not include all of them and may be repetitive in some places. This is a good supplement to your class notes, but not a replacement!
Wednesday test (basic management approaches, some fish biology, and the basic concepts of logistic equation and MSY):

What is a concave and a convex set of trade-offs?
What is the precautionary principle?
Know the logistic equation (dN/dt = …). Understand the differences between the curves we discussed relative to logistic equations and surplus production models (one reached a plateau, the other looks like an inverted “U”, a similar plot comparing effort and yield demonstrates the concept of MSY. What concepts are important to get from them?
What’s the difference between chaos and random?
Fecundity – how is it correlated with body size, survival of early life stages, parental care strategies?
Don’t get bogged down memorizing every type of parental care strategy in fish and inverts – but understand them. In other words, I might describe a strategy and ask you to interpret its utility, or ask you to compare specific strategies, but I won’t ask you to "list and describe" parental strategies.
Survival of early life stages, and growth, are key components for recruitment. Do you think it is likely that a species can have the same number of recruits in two different years but with widely different mean sizes between years? What are some major causes of recruitment variation and egg/larval mortality?

Friday test :

We have discussed several types of single-species assessment models, including surplus production models (logistic equation, logistic biomass model, simple YPR), age-structured or cohort models (more complex YPR, VPA, SCA) and stock-recruitment models. How are they different? What are their goals, limitations, assumptions?
Which of the above focuses on identifying a target to avoid growth overfishing? Which targets recruitment overfishing?
Can you answer the interpretation/concept questions from labs 4-6? Do you understand them?
Can you pick out which parts of the equation do what, as in the YPR lab when you had to delete some sections and modify the formula for the last section?
There are numerous models to describe mortality? Conceptually, how are they different?
What are the pros and cons of Stock-Recruitment models? What is the difference between the Beverton-Holt and the Ricker models? Can you represent them graphically?
What is Foraging Arena Theory? How do Walters and Martell (authors of your text) relate this to stock-recruitment models? What are the benefits of this conceptual connection?

Test 1

The test is on material covered in lecture and lab and may be any combination of definition, short answer, essay, or quantitative problem. There may even be a computer application (the test is during the lab period, so there will be time). We really haven’t started with the text yet, so this is primarily on lecture, discussion questions, and internet assignments.
Any material from our labs is fair game for the test. You don’t need to memorize formulas (I’ll provide any you might need), but you need to understand what they are used for and be able to interpret them and use them appropriately. When interpreting results, you should be very aware of the limitations and assumptions for the models. Review the major terms and concepts for each lab.
Anything from our discussion questions on the web is fair game (within reason – if I’m asking for the top 20 fisheries, for example, I don’t expect you to know them all in order, but knowing the top couple is a good idea).
What to know from our introductory lectures? – don’t worry about every little fact from the internet fishery sites, but there were a number of major trends that should be jumping out as important.
Can you recognize a gadid? Clupeid or clupeiform? Salmonid? Scombrid (tuna/mackerel)? Grouper/snapper? Flounder/halibut? How about Elasmobranch or teleost (words you’ve encountered before, but we didn’t go into them)? What about the major invertebrate fishery groups?
What are the top commercial fisheries in South Carolina? USA? World?
How is fishery production controlled by top-down and bottom-up influences?
Fish production ultimately depends on the food supply (intake) and the energy required to obtain food (expenditure). How is this balance effected by primary production levels, the type of primary production (especially size of plankton), physical and chemical conditions as they effect primary production, prey density and foraging energy expenditures, competition and predation, trophic transfer efficiency, food chain lenght, etc. Obviously this is an enormous question, but review our conversations in class. Can you talk about these things intelligently?
What are the major types of fishing gear and methods? Passive vs. active gear.
Why is there more than 1 model to describe growth? Abundance? Mortality (we haven’t gotten too far into this subject, but will continue it after the test)? What are their goals and assumptions?
What affects growth rates? What is density-dependence? What is isometric, allometric, determinate, indeterminate growth?
How do growth rates and age of maturity work together as a life history "strategy?" What is the typical compensatory reaction by a fish stock to fishing pressure?
Why be a sequential hermaphrodite?
Why are shad iteroparous or semelparous depending on where they spawn?

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