Biology of Cultured Fish
description
Transcript of Biology of Cultured Fish
Biology of Cultured FishBiology of Cultured Fish
Developed by the Harbor Branch ACTED staff
Freshwater FishFreshwater FishLess than 1% of the Earth is freshwater
• 40% of fish are freshwater • less than 5000 m deep• species are a result of evolutionary
isolation and ecological adaptation• No global species• Two species are circumpolar
Marine FishMarine FishEarth is 71% saltwater
• 60% of fish are marine • Less evolutionary variable and
ecologically isolated• The oceans provide much bigger space• Many have large ranges • 7000 m deep• 130 global species Tuna
distribution in southern oceans
Where are most fish found?Where are most fish found?
And at what depth?And at what depth?
IchthyologyIchthyology“the study of fishes”
• 25,000 living species• 53,000 scientific names• 200 new species each year
Some definitions…Some definitions…Fish – singular and plural for a species
Fishes – refers to more than one species
Fish Fishes
Taxonomy – scientific classification
Systematics – the study of the relationship among taxa; studies the history of life
Why classify organisms?Why classify organisms?
How are plants and How are plants and animals classified?animals classified?
Who? Carolus Linneaus, 1700’s, Europe
What? Developed binomial nomenclature
• Kingdom•Phylum
•Class•Order
•Family•Genus
•Species
Red Snapper
Lutjanus campechanus
How would an aquaculturist How would an aquaculturist classify fish?classify fish?
• Temperature• Salinity• Reproduction
TemperatureTemperatureCold (trout, salmon)Temp: below 15 C
Cool (catfish, striped bass)Temp: 15 – 25 C
Warm (tilapia)Temp: above 25 C
SalinitySalinityFreshwater (< 1ppt)
Brackish water (1-15 ppt)
Saltwater (15-36 ppt)
Euryhaline – adapts to different salinities
Stenohaline – cannot adapt to different salinities
OsmoregulationOsmoregulation• Aquatic species may be classified in terms of Aquatic species may be classified in terms of
their salinity tolerance as either:their salinity tolerance as either:• saltwater species• brackish water species• freshwater species
• Salinity requirements may differ for a given Salinity requirements may differ for a given species at different stages in its life cycle.species at different stages in its life cycle.
• Species adapted to a narrow range of Species adapted to a narrow range of salinities are described assalinities are described as stenohaline .
• Species which are able to tolerate a wide Species which are able to tolerate a wide range of salinities are described asrange of salinities are described as euryhaline.
OsmoregulationOsmoregulationOsmosis The net movement of a solvent across a permeable The net movement of a solvent across a permeable
membranemembrane from the side with the lower concentration from the side with the lower concentration to the side with the higher concentration.to the side with the higher concentration.
Net Direction of Flow
More ConcentratedLess Concentrated
Solvent Solute particles
Membrane
OsmoregulationOsmoregulation• For fish we can think of the body fluids as
one solution, the surrounding water as the other solution, and the parts of the body separating the two solutions as the membrane.
• In most organisms the gills are the primary membranes where osmosis occurs.
Osmoregulation: Marine FishOsmoregulation: Marine Fish• The body fluids of saltwater species are
hypotonic (dilute) relative to the surrounding water, so these species tend to lose water to the environment.
• Osmoregulation in saltwater species requires intake of water and excretion of excess salts.
Osmoregulation: Osmoregulation: Marine FishMarine Fish
Osmoregulation: Freshwater FishOsmoregulation: Freshwater Fish• The ionic composition of the body fluids of The ionic composition of the body fluids of
freshwater species isfreshwater species is hypertonic (more (more concentrated) to the surrounding water, so these concentrated) to the surrounding water, so these species tend to accumulate water from the species tend to accumulate water from the environment.environment.
• Osmoregulation in freshwater species involves Osmoregulation in freshwater species involves excretion of water and active uptake and excretion of water and active uptake and retention of salts.retention of salts.
Osmoregulation: Osmoregulation: Freshwater FishFreshwater Fish
What is a fish?What is a fish?
Photograph by HBOI
Anatomy & PhysiologyAnatomy & Physiology• Lives in water? • Carnivore, Omnivore, Herbivore• Vertebrate • Poikilotherm “cold blooded”• Fins• Gills• Senses • Lateral line• Scales• Slime (mucus)• Swim bladder “buoyancy compensator”• External or Internal Reproduction