Fisheries vocab terms: Midterm I

Fishery

The industry or occupation devoted to the catching, processing, or selling of fish, shellfish, or other aquatic animals

Subsistence fishery

Fishing for self or family; low tech; small-scale; regionally specific; can still have population impacts; earliest form of fishing

Commercial fishery

Fishing for trade or $; mass production; rapid evolution of fishing technology; capability to store and ship; artisanal (ie.mom&pop); factory ship

Recreational fishery

Became popular after WWII; no necessarily for consumption *trophy, catch & release); growing impacts; millions of sport anglers; >$billion industry in CA

Stock

Group of organisms of the same species that live in the same area and interbreed

Catch

All organisms caught during a fishing or harvesting event. Some of the catch may be discarded at sea.

Landings

All of the organisms brought back to shore

Discards

Organisms caught, but not landed - discarded at sea (dead or alive)

Underexploited

Undeveloped or new fishery. Believed to have a significant potential for expansion in total production.

Moderately exploited

Exploited with a low level of fishing effort. Believed to have some limited potential for expansion in total production.

Fully exploited

The fishery is operating at or close to an optimal yield level, with no expected room for further expansion

Overexploited

The fishery is being exploited at above a level which is believed to be sustainable in the long term, with no potential room for further expansion & a higher risk of stock depletion/collapse

Depleted

Catches are well below historic levels, irrespective of the amount of fishing effort exerted

Recovering

Catches are again increasing after been depleted

Compensation depth

Rate of C fixed is equal to rate of C used

New production

Production made during photosynthesis

Regenerated production

Recycling of nutrients in the photic zone

Gross growth efficiency

Amount of prey C converted to predator C

Trophic transfer efficiency

Ratio of predator efficiency : proportion of prey production taken by predator

r-K theory (Life History Strategy)

If a pop. is under stable conditions, nearing carrying capacity, with strong intraspecific competition, then natural selection will favor K-selection

Bet-hedging theory (Life History Strategy)

Predicts that environmental variability will cause high & variable juvenile mortality; should result in K-selection; but should favor r-selection if environmental conditions are stable & juvenile mortality is more constant

Age specific models (Life History Strategy)

Based on distinct age classes; require specific information about various life history characteristics; can predict r-K selection based on each specific age class; based on optimal reproductive effort

Fitness

The ability to survive and reproduce offspring which then survive and reproduce

Marginal value theorem

Should I stay or should I go?

Indeterminate growth

Never really stop growing, just slows way down

Determinate growth

Have a limit on how big they can get in lifetime

Longevity

Maximum life spans

Energetic standpoint

Movement is costly and therefore should not be exhibited unless there is some intrinsic value to the fish

Spatial scales

(Movement pattern)

individual to population; patrolling/ranging to migration

Temporal scales

(Movement pattern)

Diel to interannual; ontogenetic

Solar systems

(Remote sensing movement patterns)

Can identify fish to species and approximate size based on the acoustic signal that is reflected back to the boat

Lidar systems (Light Detection And Ranging)

(Remote sensing movement patterns)

Shine a beam of light into the water and then measure the spectral characteristic and intensity of the light that is reflected back

Telemetry (satellite & acoustic)

(Remote sensing movement patterns)

Allow remote estimation or calculation of location, may also provide other abiotic information

Home range

Area a fish uses on a regular basis

May be governed by resource availability (food/shelter), predation pressure, conspecific density

Ovipary

External eggs & fertilization

Aplacental vivipary

Internal fertilization, live birth w/maternal input (matrotrophy)

Oophagy

a type of matrotrophy;

Mom ovulated eggs which embryos eat in utero

Histotrophy

a type of matrotrophy;

Glycoprotein secreted by uterine vili (uterine milk)

Adelphophagy

a type of matrotrophy;

Larger embryos eat the smaller ones

Pseudo-placenta

a type of matrotrophy;

Umbilicus connection from Mom to embryo

Fecundity

#of eggs / live births

Gonadal-somatic index (GSI)

Relative measure of gonad size; gives a measure of relative contribution of reproductive investment

Mass of gonad to body mass * 100

Semelparous

Spawn once then die

Ex. Salmon, market squid

Iteroparous

Spawn over multiple years

Ex. Basses, wrasses

Batch spawners

Produce multiple batches of eggs/season

• can cause changes in GSI day to day

Unisexuality

All-female populations or species that reproduce asexually/semi-asexually

OR individual organism possesses reproductive organs of only one sex

Hermaphroditism

Individual possesses both male & female reproductive organs

Bisexuality

Individuals regularly engage in both same-sex and opposite-sex sexual activity;

OR behavioral or biological traits involving both male & female characteristics

Differentiation

Development of recognizable gonads

Maturation

Maturation of gonads to produce viable gametes

Pre-maturational sex determination

Might differentiate as females early, but before maturing some become males. Or visa versa.

ie. hagfish, lamprey, cyprinids, salmonids, gobies, blennies

ESD may occur

Environmental Sex Determination (ESD)

Environment (climate, food availability, social dynamics) determines sex

May occur in pre-maturational sex determination

Post-maturational sex determination

Change sex after they mature

Sequential hermaphrodites

Change from female to male or visa versa (Protogyny & protandry)

Show skewed sex rations towards 1st sex

Protogynous

Change from female to male

Ex. Labrids, scarids, epinephilids; CA sheephead

Usually when females are limited or prefer to mate with only the largest male

Protandrous

Change from male to female

Ex. Clownfish, pandalid, shrimp, many molluscs, crustaceans, echinoderms

Usually when even small males can fertilize many eggs and small females produce exponentially fewer eggs that large females

Gonochoristic

Those that don’t change sex

Simultaneous hermaphrodites (basslets)

Have both sexes at the same times

Size advantage model

Females are limited by gamete production (Body size), males are limited by the # of females

Harem building

Only the largest male gets to mate with all available females

If females are limited or prefer to mate with only the largest male, males will compete for females

Satellite males

An intermediate size male mimics females in behavior & morphology - allowed access to females typically defended by alpha male

“Fish cross dressers”

Sneaker males

Small males have to hide to keep from getting beaten up by larger dominant males,; will dart in while the male is distracted & spray some sperm on eggs and then flee

Ex. Toadfish

Population structure

Understanding how populations fluctuate over time & over geographical areas

Requires knowledge of age structure of populations (demographics)

Demographics

Knowledge of age structure of populations (ex. Aging methods, fecundity, recruitment)

Ecological definition of Recruitment

Number of individuals that reach a specific life stage, usually when they metamorphosis from larval stage

Fisheries definition of Recruitment

Number of individuals that reach a size where they enter the fishery

Density dependent mechanisms

High densities = more competition, predation, cannibalism, etc.

Autocorrelation

ie. Year 2 is dependent year 1

Beverton & Holt model

(Spawner-Recruit model)

Asymptotic curve with consistently high mean recruitment at high spawner abundance

Ricker model

(Spawner-Recruit model)

Parabolic shaped curved and is based on increasing density dependent mortality at high spawner abundance

Shepherd model

(Spawner-Recruit model)

3 parameter model for more complex curves

c<1 curve rises indefinitely; c=1 curve is more Beverton & Holt; c>1 curve is more Ricker

Growth

Phase of development;

Leads to changes in size or abundance of existing features

Ontogeny

Phase of development;

Leads to the appearance of new features and reorganization

Point of no return (PNR)

Larval starvation threshold (aka irreversible starvation)

Ocean stability hypothesis

Hypothesis to explain high variability in recruitment due to larval mortality;

When the ocean is calm: you get patches of high food concentration which the larvae can feed on effectively

When the ocean is rough: prey disperse & their densities become too low to support larvae

Match-Mismatch hypothesis

Hypothesis to explain high variability in recruitment due to larval mortality;

Peak primary production should closely precede(go before) peak spawning so that growing prey production (ex. Plankton) can be readily used by developing larvae - cycles must be “matched” up for larvae to find enough food to survive

Member-Vagrant hypothesis

Hypothesis to explain high variability in recruitment due to larval mortality;

The relationship between spawning time and stable ocean conditions that retained larvae is an important predictor of recruitment

Emphasizes the impact of physical factors rather than biotic

Bigger is Better hypothesis

Hypothesis to explain high variability in recruitment due to larval mortality;

Larger larvae typically show lower mortality rates - the faster the larvae grow the quicker the mortality rates decrease

• However, high growth rates are energetically costly. Plus growth capacity is physiologically & phylogenetically constrained

Environmental Window hypothesis

Hypothesis to explain high variability in recruitment due to larval mortality;

There is an optimal environmental window occuring at moderate levels of all limiting factors

Compensation

A regulatory mechanism that allows a stock to withstand additional fishing mortality & to recover from low spawner abundances

Depensation

Leads to lower then expected recruitment at low population levels - Allee Effect (pop. bottlenecks)

If R/S falls @ low spawner abundance

Ex. White abalone

Hyperstability

When catch rates overestimate actual abundance

Main cause of unexpected stock crashes

Ex. Grouper, barred sand bass, giant sea bass (spp that form seasonal aggregations)