Curation Procedures

• Fixation

– coagulate cell contents into insoluble substances

– Maintain tissue integrity, prevents autolysis

– Fragments DNA (bad)

– Decalcifies bone – reaction with formic acid

– Preserves colors

– Formalin:

• 40% formaldehyde gas in water = 100% formaldehyde

• 10% formaldehyde solution = formalin solution

• Use of anesthetics - MS-222, CO2 or ice

• ~ 1 week in fixative

• Toxicity

– Large doses bad

– Some allergic reactions

– Will fix your tissues!

• Large specimens

– Inject into abdominal cavity

– Slit open belly

Curation Procedures

• Rinse: 3-5 days in water to remove most formalin

• Preservation: maintains state of tissues

– Isopropyl alcohol: 45%

– Ethanol: 70%

– Too much alcohol will desiccate specimen

– Pigments slowly broken down

– Alcohol preservation w/out fixing first = jar of sludge after 1 year

• DNA preservation

– Place tissue sample in alcohol (100% Ethanol)

– Place rest of fish in fixative

• Catalog specimens

– Database with locality information

Fish External Anatomy

Placoid Scales

Bony Scales

• Cosmoid scales

• Ganoid scales

Bony Scales

• Most teleosts, secondary loss in some eels, catfish, other taxa

Scale growth is down (direction of arrows), new layers laid at regular intervals.

Skin Specializations

• Breeding Tubercles

• Mucus

– Functions

• Schreckstoff – “scary stuff”

Fish Color

• Pigments

– Chromatophores –

– Amount of color controlled by

• Named by the pigment contained within

– melanophores –

– erythrophores –

– xanthophores –

– leucophores –

Structural Colors

• Schematochromes or Iridiophores –

• Predator confusion –

• Crypsis –

• Color Patterns

– Transparency

– Countershading

Bioluminescence

• All are marine, most deep water

• Cellular light

• Bacterial source

• Anatomy

• Functions

Fins and locomotion

• Advantages/disadvantages of water

• Effective movement requires

– Propulsion (forward and/or back)

– Guidance

– Braking

Propulsion

• Basic fish body plan

• Early propulsion

• Fin evolution

Myomeres and Vertebrae

• Evolutionary trend towards fewer segments, more rigid body – Why?

# of myomeres (and vertebrae)

16 - Molidae 600 - Nemichtyidae

Body undulations Caudal locomotion

Caudal locomotion

Anguilliform locomotionTypes ofSwimming

Anguilliform Subcarangiform Carangiform Thunniform

rudders& lift

locomotion& rudders

Propulsion, braking, anti roll

center of gravity

Fins and SwimmingRemember that fish are neutrally buoyantPosition and shape of fin

Secondary functions –

Spines and Rays

• Spines

• Rays

Dorsal and Anal Fins

KeelsProtectionSignaling

Spiny dorsalProtectionSignalingRudderMay be folded away

Soft dorsal and analPropulsionBrakingKeel

Paired Fins

• Pectoral, Pelvic serve to guide, steer and in some cases propel

• More maneuverability

• Other modifications

More maneuverable, slowerLess maneuverable, faster

Caudal Fin

• Homocercal vs. heterocercal

• Aspect ratio

• In faster swimming fishes

Increased swimming speed

Bony elements in tail

• Hypural plate