SNR315 fisheries final

fins, gills, aquatic, vertebrae, scales

characteristics of a fish

fishery

organized unit to catch fish/aquatic species

ornamental, recreation, food

purposes of fisheries

region, population, type of waterbody

fisheries are based on

fish, habitat, people

fundamentals of fisheries management

stocking

what is used to counteract over harvest

Dingell-Johnson Act

placed a tax on fishing gear/boats

stakeholders

who makes the value decision

professionals

who makes the technical choices

policy makers

who makes the policy choices

adaptive management

1. inventory

2. strategic planning

3. operational planning

4. monitor/evaluation

inventory

current status (adaptive management)

strategic planning

set goals and objectives (adaptive management)

operational planning

identify strategies (adaptive management)

monitor/evaluation

did we accomplish goals? (adaptive management)

qualitative

goals are ______

quantitative

objectives are _______

specific

measurable

achievable

realistic

time bound

S.M.A.R.T.

births, immigration, deaths, emigration

_____ + _____ = population = _____ - ________

true abundance

total # of fish in the area

density

# of fish per given area

relative abundance

# of fish caught per unit effort

c- # of fish caught

f- unit of effort

q- catch ability coefficient

N- true abundance

relative abundance variables

c/f=qn

constant

catch ability coefficient is _____

mark-recapture

fin clips, external tags/internal tags

mark-recapture

1. equal probability of capture

2. closed population

3. no marks lost/missed

4. mark doe snot influence behavior

5. marked/unmarked mix randomly

1. equal probability of capture

2. closed population

3. no marks lost/missed

4. mark doe snot influence behavior

5. marked/unmarked mix randomly

assumptions of mark-recapture

N- total

M- first capture

C- second capture

R- recapture

Lincoln-Petersen variables

N=MC/R

single

Licon-Petersen is for ____ marking, ____ recapture

N- total

M- first capture

C- second capture

R- recapture

Schnabel variables

N=EMiCi/ERi+1

multiple

Schnabel is for ____ marks, ____ recaptures

Schnabel, Lincols-Petersen

models used for mark-recapture

removal/depletion

1. closed population

2. q is constant

3. enough fish removed to decrease CPUE

4. catch removes over 2% of population

5. equal probability of capture

6. units of effort are independent

1. closed population

2. q is constant

3. enough fish removed to decrease CPUE

4. catch removes over 2% of population

5. equal probability of capture

6. units of effort are independent

removal/depletion assumptions

Leslie method

model used for removal/depletion

Lt= length at age t

L∞= max length

K= growth coefficient

t0= length at age 0

von Bertalanffy growth variables

Lt= L∞(1-e^-k(t-t0))

von Bertalanffy

growth model

negative

t0 should be a _____ number

otolith

most accurate way to age fish, but requires killing (ear)

females

are females or males larger

juvenile, switch from size to repro growth

do adults or juveniles grow faster? why?

trawl

which sampling effort catches younger fish

anglers

which sampling effort catches older fish

salt

does fresh or saltwater have a higher growth potential

anadromous

spawn in fresh, grow in salt

catadromous

spawn in salt, grow in fresh

3, C

what recruitment curve are fish? chase?

recruitment

# of individuals that reach a specific stage in the life cycle

egg, larvae, 0-group, juvenile, adult

recruitment flow (youngest to oldest)

0-group and juvenile

which aspects of recruitment flow is biological recruitment

adult

which aspect of recruitment flow is fishery recruitment

trophodynamics

food based interactions

hydrodynamics

water movement

interspecific interactions

competition/predation

abiotic factors

temp, wind, water

spawning stock

# of viable spawners in a population

Hjort's critical period

transition from yolk shack to finding food

Cushing's match-mismatch

when zooplankton overlaps with larvae stage, recruitment increases

Hjort's aberrant drift

movement of larvae out of typical environment decreases recruitment

carrying capacity

# of individuals a habitat can sustain

space

what is a limiting factor to species that nest

by-catch

non-target species accidentally caught

harvest

target species caught

post-release discard

fish that die after being caught and released

decreases

as fishing mortality increases, natural mortality _______

Nt= population size at t

N0= initial population size

t= time

z= instant mortality rate

density dependence/mortality variables

Nt= N0e^-zt

z

descending arm slope

catch curve

1. closed population

2. mortality is constant

3. q is constant

4. sampling gear is unbiased

5. accurate ages

6. recruitment is constant

1. closed population

2. mortality is constant

3. q is constant

4. sampling gear is unbiased

5. accurate ages

6. recruitment is constant

catch curve assumptions

protected slot

lengths greater than or less than the slot CAN be caught

harvest slot

lengths greater than or less than the slot CANNOT be caught

maximum sustainable yield

largest harvest that can be taken without depleting the environments ability to replenish itself

overfishing

activity of catching fish faster than they can reproduce

overfished

fish population that has fallen below the healthy level

put-take

stocking fish of size that are ready to be harvested

put-grow-take

stocking fish that need to grow before being harvested

enhancement

improving the forage base, value-added

biological

adding species to control undesired organisms

restoration/conservation

Stocking of extirpated, threatened, or endangered species

fry/larva, fingerlings, adults

stocking life stages

imprinting

the process of forming attachments during a critical period very early in life

somatic growth

growth of the body (length/weight)

hard

what parts of a fish do we use to measure age

American Fish Cultureists Association

org. formed during the period of fish culture and stocking

learning about fish and conducting surveys

1800-1900

fish stocked as a result of hoverharvest

1875-1925

rise of sport/leisure fishing

1900

dam construction

1930-1970

environmental protection, community level

1960-now

Hyper-aggregation

A condition where fish are found in very high densities

Hypo-aggregatio

A condition where fish are found in low densities.

oligotrophic

enviro that is poor quality and supports few fish

mesotrophic

enviro that is moderate quality; supports fish/plants

eutrophic

enviro that is high quality; high algae concentration

planktivorous

feeds on plankton

invertivorous

Feeding on invertebrates

piscivorous

feeding on fish

omnivorous

Feeding on both animals and plants

ontogenetic shift

organisms change their feeding patterns throughout their lifetime;

secondary carnivore

primary carnivore

herbivore

autotroph

trophic levels (top to bottom)