cons 486 definitions and concepts

fish

aquatic animal with gills that lacks limbs with digits

three components to a fishery

1. aquatic resource

2. aquatic environment

3. harvesting resources

fisheries management

aims to maintain a sustainable fishery resource that provides for an economically viable and diverse industry

conservation physiology

integrative scientific discpline applying physiological concepts, tools, and knowledge to characterize biological diversity and understand responses to environmental stressors

energy

ability to do work

metabolism

chemical reactions that convert stored energy into usuable energy

energetics

study of processes involved in energy conversion

aerobic metablism

conversion of glucose in the presence of oxygen into CO2, water, and energy

red muscle

involved in aerobic metabolism

anaerobic metabolism

takes place when fish need energy, but the blood oxygen is limited

white muscle

involved in anaerobic metabolism; burst swimming

standard metabolism

the rate of energy use by fasting fish at rest

active metabolism

the rate of energy use that a fish can sustain as a result of swimming activity

ectotherms

body temp is controlled by external temps

poikilotherms

body temp varies

scope for activity

difference between active rate and standard rate; difference shows ability to do work aerobically at any given temperature

where is the scope for activity the smallest?

where active and standard metabolism intersect; called the critical temperature

critical temperature

temperature where they can die

optimum temperature

temperature where the scope is the greatest, enables fish to aerobically swim fasted for prolonged periods of time

energetics

study of processes involved in energy conversion

bioenergetics

study of energy flow through living systems

maintenance ration

minimum ration so that weight remains the same

maximum ration

max amount of food that can be eaten/digested

what are the three energy fates

1. waste

2. metabolism

3. growth

egestion

feces and urine

excretion

gill ion exchange

specific dynamic action (SDA)

costs of processing food in stomach and intestines

energy budget

partitioning of energy into different uses can be thought of in terms of a balanced equation

energy budget equation

C = metabolism + waste + growth

energy budget prioritization

consumed energy is first allocated to

1. metabolism

2. waste

3. storage

what will be given up first with lack of energy?

fish will give up reproduction first and then growth

fecundity

number of eggs per female

offspring reproduction

related to the number of and the fecundity of females

within-species, what is fecundity related to?

body size —> larger females have higher fecundity

life history

traits and schedules that affect an organism’s life table

broadcast spawning

spawn in open areas of the ocean and let gametes go

nest defense

build a nest and protect for 6-8 weeks

brooding

brood fertilized embryo internally or externally

increasing level of parental care

broadcast < scatter < shelter < nesting < guarding < brooding

shelter

hide eggs in the habitat

bubble nests

create bubbles at the surface and hide eggs in bubbles

what happens to eggs size with different levels of parental care?

with more parental care, there are less eggs

semelparity

spawn once and die

iteroparity

repeat spawners

iteroparous

conserve energy by spreading out reproductive effort over time

semelparous

put all possible energy into reproduction

equilibirum species

tend to live near carrying capacity

opportunistic species

extreme end of the spectrum; strategy for disturbed environments

bet-hedging

to protect against the wrong choice

anadromous

migrate from saltwater to freshwater to spawn

maturity

point when fish are able to sexually reproduce following energy investment into gonads (and secondary sexual characteristics → salmon)

what does a fast growth rate mean?

fast growth rate means a lower age at maturity

if mortality of young fish is excessively high…

then selection favours early maturation

if mortality caused by the act of spawning is high…

then selection favours maturation as late as possible to enable more time for growth

senescence

energy required to sustain routine body function, less required for reproduction

competition at two levels

1. individual: influence growth

2. population: control population size

density dependent growth (DDG)

occurs at environmental carrying capacity; if available ration is reduced then individual body size decreases

density independent growth (DIG)

if ration is high because of low abundance and high food per capita (below carrying capacity)

how do predatory fish attack?

attack side of the head of their prey, few fish strike from behind and bite pieces off

littoral zone

well lit, high plant growth, large inpus of LW and leaf litter

shoreline area extends to edge of rooted vegetation

limnetic zone

open water, little influence of large wood/other structures

plankton zone (sunlight → photosynthesis → O2 production)

profundal zone

bottom sediments (soft and muddy), can become anoxic

oligotrophic lakes

• Young and deep

• Nutrient input from the watershed is low

• Small littoral area with few plants

• Low levels of detritus and decomposition

• Abundant oxygen throughout the entire lake

• Low phyto, zooplankton, and fish production

• Small epilimnion relative to hypolimnion

• Hypolimnion is well oxygenated all year → good habitat for some fish

eutrophic lakes

• Old and shallow

• Nutrient rich

• High phytoplankton and plants

• Large littoral and epilimnion → contributes to abundant warm water fish

• Hypolimnion is small and anoxic/hypoxic → poor salmon habitat 

• The older the lake, the more profundal is filled in

trophic pyramids

display food structure of an ecosystem

river continuum concept

continuum between narrow low-order streams and wide high-order streams

food webs

arrows show energy flow

what are top-down cascade patterns affected by?

biotic processes

what are bottom-up cascade patterns affected by?

abiotic processes

reservoir

artificial lake

what are the three zones of longitudinal gradients?

riverine, transitional, lacustrine

riverine zone

reservoir is fairly narrow, and shallow

• High flow rates

• High suspended solids

• High nutrients

• Low light penetration

  • Energy derived from allochthonous means → no thermal stratification

lacustrine zone

reservoir is wide and usually deep

• Low flow rates

• Low suspended solids

• Low nutrients

• High light penetration

• Sometimes has thermal stratification → energy derived from autochthonous means 

• Oligotrophic reservoirs will have high oxygen in the hypolimnion

  • Eutrophic reservoirs will not

transitional zone

all characteristics are intermediate relative to riverine and lacustrine

• Constant addition of nutrients, OM, and light penetration

• Constant export of production

• Highest production of phyto/zooplanton in this zone

  • Nutrients and food resources end up here

  • Little stratification → whole zone is involved in this production

trophic upsurge

food and space resources become super abundant

trophic depression

• Occurs 5-20 years after startup

• Nutrient input decreases, and the vegetation breaks down

• Competition for limited food and space intensifies

• Sedimentation of spawning areas can also occur

• Standard water withdrawals prevent the littoral area from developing

  • Fish habitat changes from benthic-dominated to pelagic-dominated; only the structure would be rocks

intertidal zone in oceans

near shore habitat changes with tidal influence, continuously mixed by winds and tides

sub-littoral zone in oceans

portion of littoral that extends to the edge of continental shelf

neritic zone in oceans

littoral and sub-littoral

pelagic area in oceans

high seas or open oceanep

epipilagic area in oceans

mixed layer, upper 200-500m

gyres

spiral or vortex resulting from wind, planetary motion, and friction

if water is more dense

higher salinity or cooler temps

if water is less dense

lower salinity or warmer temps

sea-grass beds are

marine ‘fields’

kelp beds are

marine ‘forests’

user (fisher)

capture fisheries resources

hook and line

rod and reel angling or trolling

recreational

leisure activity, fish are often consumed by not sold

commercial

business activity, fish sold for money

longlines

series of baited hooks attached to floats (left to passively fish)

trolling

active form of dragging baited or lured hooks from a boat

trawls and dredges

bag with cod-end dragged through water column or on bottom

seines

fine mesh curtain with a floating top and sinking bottom

trapnets and weirs

gear is fixed in one spot, usually nearshore

traps or pots

portable gear, set at any depth

gillnets

long wall of mesh that can be set at any depth, anchored to shore, boat, or the bottom

subsistence

user consumes the resource, source of protein, or cultural importance

population recruitment

production offspring that survive to sexual maturity and reproduce

fisheries recruitment

production of offspring that reach a harvestable body size