Reading Assignment:

1
Reading Assignment

• Chapter 10--Sensory Perception

Fish ear
end
2
Growth

• Longevity
• unconfirmed reports of carp 200-400 yr.
• authenticated records for carp 50 yr.
• large fish-few gt 12-20 yr.
• some marine spp gt 100 yr. thornyspines, orange
  roughy
• many small spp-2 yr. or less (sardines,
  anchovies)
• Note aging with scales, bones, otoliths

end
3
end
4
(No Transcript)
5
Growth Other Generalities

• females often larger than males
• growth rate varies with temp.
• longevity inversely proportional to temp.
• stress reduces growth
• dominance hierarchies - dominant get food
• overcrowding can lead to stunting
• indeterminate growth - grow throughout life
• growth highly variable - can loose weight

end
6
Bioenergetic Definition of Growth

• energy accumulation (calories) vs. length or
  weight

end
7
Bioenergetics continued

• Energy Budget
• I M G E
• where I ingested energy
• M energy expended for metabolism
• G energy stored as growth
• E energy lost to environment

end
8
Bioenergetic Energy Budget
I
E
end
9
Bioenergetics continued

• Ex M energy for body repair
• maintenance
• activity
• digestion

end
10
Bioenergetics continued

• Ex E energy in feces
• ammonia, or urea
• mucus
• epidermal cells

end
11
Terms

• Standard Metabolic Rate
• maintenance met. no growth, no activity
• Routine Metabolic Rate
• typical met. routine growth activity
• Active Metabolic Rate
• max. aerobic metabolism

end
12
Factors Affecting Growth Temperature
routine
active
standard
scope
Metabolic Rate
activity
growth
Where would growth be best?
Temperature
end
13
Factors Affecting Growth Temperature
normal O2
reduced O2
Metabolic Rate
reduced scope
reduced growth
Temperature
end
14
Growth will not occur at low O2
Ex LMB cease growing below 5 mg/L
end
15
Factors Affecting Growth Dissolved oxygen
Routine Metabolism
critical O2 concentration
Dissolved Oxygen mg/L
end
16
end
17
Effect of Ammonia on Growth

• NH3 is more toxic than NH4
• relative Conc. Depends on pH
• at 24C 0.5 NH3 at pH 7
• 34 NH3 at pH 9
• 96 hr LC50 3.8 mg/L NH3
• as low as 0.6 mg/L for some spp.
• slow growth tissue damage at 0.006-0.34 mg/L
  (continuous exposure)

Aquarium problems
Transport problems
end
18
Effects of other factors on growth

• Growth reduced at sub-optimal salinities

end
19
Model effect of environment on fishes
scope
simplify
Metabolism
Environmental Variable
end
20
Model continued
Scope
Environmental Variable
end
21
end
22
Overview of Reproduction

• Varies greatly among fishes
• 1. behavior
• courtship behavior
• nest building
• parental care versus no care
• mixed behaviors
• sneaker bass
• sneaker and mimic bluegills
• migration
• anadromy- spawn in FW, mature in SW
• catadromy - spawn in SW, mature in FW

eels
end
23
Anadromous salmon
end
24
Overview of Reproduction continued

• 2. Anatomy
• claspers - chondrichthyes
• gonopodium - Poeciliidae
• sexual dimorphism
• males larger in territorial species (salmon)
• females usu. larger in others

end
25
catshark with claspers
claspers
end
26
black molly gonopodium
end
27
gonopodium
end
28
Sexual dimorphism in salmon
female
male
end
29
Overview of Reproduction continued

• 3. Physiology
• sex chromosomes
• XY M XX F (most)
• ZZ M and ZW F (Poeciliidae Tilapia spp)
• some fishes have 3 or more sex chromosomes
• sex not under complete genetic control
• hermaphrodites--both sexes (many in Serranidae)
• usu. one sex at a time
• exception hamlet (serranid)
• sex changes--bluehead wrasse

end
30
bluehead wrasse (Labridae)
male

• harem

• dominance hierarchy

• dominant F becomes M

female juv.
end
31
Overview of Reproduction continued

• 3. Physiology continued
• parthenogenesis -- egg develops w/o
  fertilization
• Ex Amazon molly
• all female
• produce genetic clones
• Ex gynogenesis in Phoxinus (Cyprinidae)
• all female
• gynogenesis--sperm required, DNA from male not
  incorporated in embryo

end
32
Reproductive Modes in Fishes

• Oviparous -- egg layers most fishes
• internal or external fertilization
• Ovoviviparous
• internal fertilization
• eggs hatch internally
• live birth
• yolk only nutrition
• EX Lake Baikal sculpins
• marine rockfishes
• some sharks

end
33
Lake Baikal
Approx. 400 mi. long
5315 ft
gt 1 mi. deep
end
34
Reproductive Modes in Fishes continued

• Viviparous--live birth
• nutrition provided directly by mother
• EX embryonic cannibalism -- a few sharks
• fins against uterine wall -- surf perches
• placenta-like structures--pericardial tissues in
  Poeciliidae

end
35
nurse shark embryos
end
36
lemon shark pup
yolk sac and stalk function like placenta and
umbilical cord
end
37
Reproductive Strategies

• Energy Investment
• egg size number vs. survivability
• carp gt 2,000,000
• salmon 1500-2000
• parental investment energy vs. surviv.
• nest building
• parental care
• mouth brooders--cichlids ariids

end
38
Parental care pouches (seahorses, pipefishes)
end
39
male
female
end
40
Parental care guarding
smallmouth bass--males
bullhead--both sexes
end