Exotics - block 1 flashcards

Vocabulary flashcards covering key terms and concepts from fish evolution, aquaculture, water quality, and aquatic pathogens.

Actinopterygii

Ray-finned fishes; the major group of modern bony fishes that includes most teleosts.

Teleosts

A highly diverse subgroup of Actinopterygii; the most modern ray-finned fishes with many evolutionary innovations.

Ray-finned fishes

Fishes with fins supported by bony rays; a major characteristic of Actinopterygii.

Jawless fishes

Early vertebrates without jaws or paired fins; ancestral to jawed fishes.

Percomorpha

A large clade within Perciformes (a major teleost group) highlighted in the notes.

Perciformes

Order commonly referred to as perch-like fishes; a dominant group among teleosts.

Oreochromis niloticus

Nile tilapia; example species in aquaculture.

FAO definition of aquaculture

The farming of aquatic organisms with intervention in rearing to enhance production and ownership of stock.

Aquaculture growth (rate)

Fastest-growing sector of the world food economy, increasing by more than 10% per year.

Aquaculture’s share of fish consumption

Accounts for more than 30% of all fish consumed worldwide.

Lateral line

A sensory system running along the body to detect water movement and vibrations.

Otoliths

Calcium carbonate ear stones in fish used for balance, movement, and age estimation.

Myomeres

Segmented muscle blocks that contract in waves for undulatory swimming.

Pyloric caeca

Digestive extensions that secrete enzymes; number varies by species.

Ganoid scales

Hard, enamel-like scales with a smooth outer edge; one type of teleost scale.

Cycloid scales

Smooth, rounded-edged scales common in many teleosts.

Ctenoid scales

Scales with comb-like (toothed) edges.

Melanophores

Pigment cells that produce black or brown coloration.

Lipophores

Pigment cells that produce yellow to orange coloration.

Iridophores

Reflective pigment cells that produce iridescent, often colorless, effects.

Chromatophores

Pigment-containing cells responsible for color changes in skin.

Swim bladder

Gas-filled organ that provides buoyancy and can act as a sound chamber; regulated in some species.

Physostomous

Gas bladder connected to the gut via a pneumatic duct; gas can be gulped or expelled.

Physoclistous

Gas bladder not connected to the gut; gas regulation via a gas gland and rete mirabile.

Gas gland

Tissue that helps regulate gas release into or from the swim bladder.

Rete mirabile

Counter-current vascular network enabling regulatory gas exchange in the swim bladder and other tissues.

Dorsal fin

One or more fins on the back of the fish; unpaired fin(s) used in stabilization and steering.

Anal fin

Unpaired fin on the ventral side near the tail; contributes to stability.

Caudal fin

Tail fin; primary propulsion in many fishes.

Pectoral fin

Front paired fins used for steering and braking.

Gadidae

Cod family; notable for distinctive multi-dorsal fins and fin arrangements (e.g., Atlantic cod, hake).

Nitrification

Biological oxidation of ammonia to nitrite and then to nitrate by specialized bacteria.

Nitrosomonas

Ammonia-oxidizing bacteria that convert NH3/NH4+ to NO2-.

Nitrosospira

Another group of ammonia-oxidizing bacteria involved in nitrification.

Nitrobacter

Nitrite-oxidizing bacteria that convert NO2- to NO3-.

Nitrospira

Nitrite-oxidizing bacteria contributing to nitrate formation in nitrification.

NO2- (Nitrite)

Intermediary product in nitrification; can be toxic at high levels.

NO3- (Nitrate)

End product of nitrification; generally less toxic but can accumulate and affect growth.

TAN

Total Ammonia Nitrogen; sum of NH3 (toxic) and NH4+ (less toxic) forms.

FAN

Free Ammonia Nitrogen; the more toxic NH3 form of ammonia.

NH4+

Ionized ammonium form; less toxic than NH3.

DO

Dissolved Oxygen in water; essential for fish respiration.

DO_min

Minimum DO recommended to prevent stress and mortality.

DO_opt

Optimal DO range for healthy fish production.

pH

Log-scale measure of hydrogen ion concentration; affects many chemical equilibria in water.

KH

Alkalinity; buffering capacity of water that helps stabilize pH.

GH

General hardness; concentration of divalent cations (Ca2+, Mg2+).

Salinity

Total concentration of dissolved salts in water; measured in ppt.

Refractometer

Instrument to measure salinity or salinity-related properties via refractive index.

Biofilter

Biological filtration system housing nitrifying bacteria to process nitrogenous wastes.

Nitrifying bacteria cycling (biofilter maturation)

Process where nitrifying bacteria establish in 2–6 weeks, enabling nitrite and nitrate processing.