BIOL 316 Midterm Test Questions with Correct Answers Latest Update 2025-2026
Reproduction Effort - Answers investment of energy into reproduction. Can be measured in
several ways: number of eggs per female, biomass of eggs per female, and GSI. Often
discussed in terms of whole energy budget
Gonadosomatic Index (GSI) - Answers weight of the gonads expressed as a percentage of body
mass. One of the most useful measures of reproductive effort
Whole Energy Budget Equation - Answers C = Pr + Pg + R + U + F. Breakdown of what energy is
expended on. C = input of energy (caloric), Pr = energy into reproduction, Pg = energy into
growth, R = energy into metabolism, U = energy into urinary and non-fecal excretions, F = energy
into fecal excretions
Why is it important to understand the energy budget - Answers Growth slows as fish reach
maturity (then begin expending more E for reproduction). Can indicate the age of maturity
Energy budget can also show how stress affects reproduction. Stress causes an elevation in
metabolism (R) - less E available for reproduction (Pr)
Semelparity and Iteroparity - Answers Semelparity: one time investment into reproduction. i.e.
Pacific salmon. Good strategy for stable conditions, or when there are compensatory
mechanisms to make up for failure caused by fluctuating environmental conditions.
Compensatory mechanisms = overlapping generations and straying
Iteroparity: several investments into reproduction. Atlantic salmon. Good strategy when
environmental conditions are not stable. If unsuccessful in one attempt, can try again.
Oviparous and Viviparious - Answers Oviparous: lay eggs. Many offspring
- Fish with large numbers of eggs/offspring may recover better from overfishing
Viviparous: females release hatched young (well-nourished juveniles/young adults). Fewer
offspring
BOFFFF - Answers Big old fat fecund female fish
Bony Fish - Egg Protection and Parental Care - Answers Typically some form of parental care.
Guarding of eggs and offspring is most common form. Other parental care behaviours include
nest building, cleaning of spawning substrate, fanning eggs, internal gestation, oral brooding,
and burying eggs
, Explain why most of the mortality in fish species occurs in early-life history stages (5) - Answers
1) Rapid growth to survive - small = most susceptible to predation
2) Rapid growth is dependent on the switch from phytoplankton to larger prey (ex. Zooplankton
and prey fish). Growth is dependent upon location (prey density) - at the mercy of their
environment.
3) More susceptible to changes in pH and salinity in early life history. Can be harmed by acid-run
off, acute changes in temperature, and currents/wave actions (environmental disturbances).
4) A lot of mortality occurs at this time due to starvation. Feeding is limited by: development of
the sensory systems and feeding apparatus (gape size), and the ability to move/swim well
enough to capture food.
5) Competition: all spawn in the same area, at the same time. Those who spawn earlier have an
advantage - have more time to grow and can prey on those who spawn later. Competition is
high.
Recruitment - Answers Refers to the relative number of fish that survive the early life history
challenges to become a part of the adult population. Determines how many fish are added to
the overall population in a given year
Year Class Strength - Answers Relative success of recruitment in any given year. Number of
new recruits per spawning year.
Recruitment Models - Answers used to describe/determine recruitment. Used to understand
biotic and abiotic factors that affect recruitment. Used to determine the number of fish that can
be harvested sustainably, and if fisheries can improve recruitment (i.e. add large rocks to rivers
to increase spawning)
Models to Describe Relationship between Number of Spawners and Number of Predicted
Recruits (3) - Answers Exponential: slope = maximum reproductive rate. Each pair of spawners
produces many recruits to the population. Only a few adults can produce a large number of
eggs/recruits
Beaverton-Holt: exponential growth when population is small - slope near origin represents
maximum reproductive rate. Also incorporates maximum carrying capacity that will be
Reproduction Effort - Answers investment of energy into reproduction. Can be measured in
several ways: number of eggs per female, biomass of eggs per female, and GSI. Often
discussed in terms of whole energy budget
Gonadosomatic Index (GSI) - Answers weight of the gonads expressed as a percentage of body
mass. One of the most useful measures of reproductive effort
Whole Energy Budget Equation - Answers C = Pr + Pg + R + U + F. Breakdown of what energy is
expended on. C = input of energy (caloric), Pr = energy into reproduction, Pg = energy into
growth, R = energy into metabolism, U = energy into urinary and non-fecal excretions, F = energy
into fecal excretions
Why is it important to understand the energy budget - Answers Growth slows as fish reach
maturity (then begin expending more E for reproduction). Can indicate the age of maturity
Energy budget can also show how stress affects reproduction. Stress causes an elevation in
metabolism (R) - less E available for reproduction (Pr)
Semelparity and Iteroparity - Answers Semelparity: one time investment into reproduction. i.e.
Pacific salmon. Good strategy for stable conditions, or when there are compensatory
mechanisms to make up for failure caused by fluctuating environmental conditions.
Compensatory mechanisms = overlapping generations and straying
Iteroparity: several investments into reproduction. Atlantic salmon. Good strategy when
environmental conditions are not stable. If unsuccessful in one attempt, can try again.
Oviparous and Viviparious - Answers Oviparous: lay eggs. Many offspring
- Fish with large numbers of eggs/offspring may recover better from overfishing
Viviparous: females release hatched young (well-nourished juveniles/young adults). Fewer
offspring
BOFFFF - Answers Big old fat fecund female fish
Bony Fish - Egg Protection and Parental Care - Answers Typically some form of parental care.
Guarding of eggs and offspring is most common form. Other parental care behaviours include
nest building, cleaning of spawning substrate, fanning eggs, internal gestation, oral brooding,
and burying eggs
, Explain why most of the mortality in fish species occurs in early-life history stages (5) - Answers
1) Rapid growth to survive - small = most susceptible to predation
2) Rapid growth is dependent on the switch from phytoplankton to larger prey (ex. Zooplankton
and prey fish). Growth is dependent upon location (prey density) - at the mercy of their
environment.
3) More susceptible to changes in pH and salinity in early life history. Can be harmed by acid-run
off, acute changes in temperature, and currents/wave actions (environmental disturbances).
4) A lot of mortality occurs at this time due to starvation. Feeding is limited by: development of
the sensory systems and feeding apparatus (gape size), and the ability to move/swim well
enough to capture food.
5) Competition: all spawn in the same area, at the same time. Those who spawn earlier have an
advantage - have more time to grow and can prey on those who spawn later. Competition is
high.
Recruitment - Answers Refers to the relative number of fish that survive the early life history
challenges to become a part of the adult population. Determines how many fish are added to
the overall population in a given year
Year Class Strength - Answers Relative success of recruitment in any given year. Number of
new recruits per spawning year.
Recruitment Models - Answers used to describe/determine recruitment. Used to understand
biotic and abiotic factors that affect recruitment. Used to determine the number of fish that can
be harvested sustainably, and if fisheries can improve recruitment (i.e. add large rocks to rivers
to increase spawning)
Models to Describe Relationship between Number of Spawners and Number of Predicted
Recruits (3) - Answers Exponential: slope = maximum reproductive rate. Each pair of spawners
produces many recruits to the population. Only a few adults can produce a large number of
eggs/recruits
Beaverton-Holt: exponential growth when population is small - slope near origin represents
maximum reproductive rate. Also incorporates maximum carrying capacity that will be
