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ge, Growth, and Mortality of Fi

Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

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Page 1: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Age, Growth, and Mortality of Fish

Page 2: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Age and growth studies can be used to determine

– maturity– age-related growth rates– survival/mortality rates, longevity– population age structure

Page 3: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Three Approaches to Aging

1. fish held in "confinement" or marked and released at known age and then recaptured

• primarily “validation” of aging process

2. length frequency• assessment through modes in length-frequency distribution• typically most valuable for one or two years• does not work well in locations that lack well-defined growth seasons or are protracted spawners

3. anatomical approach• most common• based on calcified structure (hard parts)• structures used depends upon species and latitude• all are invasive except for scales

Page 4: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Length-frequency Distribution

Page 5: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,
Page 6: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

many fishesmany fishescatfish, common carpsuckers, sturgeongoosefishes, skates (marine)pikesyellow perch, smallmouth basspaddlefish

scale =>otolith =>spine =>fin rays =>vertebrae =>cleithrum =>operculum =>jawbone =>

Aging Fish by Hard Parts

Page 7: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Fish Scale Types

Page 8: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Features of a Ctenoid Scale

focus

annulus/annuli

circulus/circuli

ctenii

radius/radii

exposed portion

buried portion

edge

Page 9: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Scales may have well-defined annuli in northern U.S. because of defined seasons (at least first several years of life)

Scales from fish living at more equatorial latitudes often lack annuli because of extended growing season

False annuli can be formed when other stressors become involved, such as spawning, drought, etc.

Page 10: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Collection of Scales• often with knife• from particular areas on the fish• take several because regenerated scales will be missing some annuli

Page 11: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Scale are read; if older and opaque, an impression is made by pressing between plastic or acetate slides

Using a microfiche reader, such as in Miller Library

Page 12: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Annulus is actually the result of closely spaced circuli

Age-2 White Crappie, collected in fall (just finishing third growing season)

Page 13: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Aging Fish by Scales

1st year growth

2nd year growth

3rd year growth

Page 14: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

White Crappie collected in July; Age 5

Page 15: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Regenerated Scale

Page 16: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,
Page 17: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,
Page 18: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Otoliths• lapillus, sagittus, and astericus - "ear bones"• sagittal otolith commonly used for aging

Semicircular canals of inner ear

Page 19: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Otolith removal

Page 20: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Used whole or sectioned by saw; sometimes polishing or burning the edge is required

Age-6 White Crappie, spring

Age-4 WHB, spring

Page 21: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Age-4 Yellow Perch, spring

Opercula (singular: operculum)

Page 22: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Age-4 Smallmouth Bass, spring

Page 23: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,
Page 24: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,
Page 25: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,
Page 26: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Cross-section of a lake sturgeon fin ray showing annuli to estimate age (8yrs old).

Page 27: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

Otolith and Scale of 5 Yr Brown Trout

Page 28: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,
Page 29: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,
Page 30: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,
Page 31: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,
Page 32: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,
Page 33: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,
Page 34: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,
Page 35: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,
Page 36: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,

What can be learned from aging studies:

Comparison of Black Crappie (Pomoxis nigromaculatus) growth in 3 different lakes in South Dakota

Page 37: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,
Page 38: Age, Growth, and Mortality of Fish. Age and growth studies can be used to determine – maturity – age-related growth rates – survival/mortality rates,