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Swimming and Morphology

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Swimming - modes

Anguilliform - using the body plane through undulations; 1 or morewavelengths per body length (eel, lamprey, burbot)

Subcarangiform - between 1/2 and 1 wavelength per body length (Salmonids).

Carangiform - less than 1/2 wavelength per body length.

Thunniform - low drag, highly fusiform, lunate tail (tunas and sailfishes)

Ostraciform - Sculling motion of the isocercal caudal fin (Boxfish)

Rajiform - Horizontal undulations of large pectoral fins (rays and skates) Labriform - Thrusting of long pectoral fins in an oaring motion (wrasses)

Amiiform - Vertical undulations of the dorsal fin (bowfin, seahorses, and pipefish)

Gymnotiform - Vertical undulations of anal fin (knifefish)

Balistiform - Simultaneous vertical or horizontal undulations of dorsal and anal fins(triggerfish, halibut, and some cichlids)

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Swimming - modes

Functional Morphology Plane Cruisers (Active species, Jobling p 256)

Accelerator(Fast-start performance,Jobling p 262

Maneuverer (Sunfish)

Generalist (Jobling p 263)

Continuum of swimming modesUndulatory to Oscillatory and everything in between

Undulatory is wave motion created in fin or body

Oscillatory is the pivoting of a fin on a stationary base

Functional Morphology

Plane

Cruiser

Accelerator

Maneuverer

Generalist

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Performance Envelope- General

Temperature Tolerance

Acclimation to a giventemperature can

change the temperature

tolerance of a species.

Basically, warm fish can

tolerate higher tempsthan cold fish and cold

fish can tolerate colder

temps than warm fish.

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Species Envelopes-Temperature

Examples oftemperature

preference

envelopes for

several species

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Species Envelopes-Swimming

Oxygen consumption

increases withtemperature increase

Note the change in

standard (basal)

metabolic rate (lower

line) as temperature

increases, and active

metabolic rate (upper

line).

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Poikilothermia

fish are cold-blooded

can raise their body temp through exercise a little, butwarmth soon lost at gills

All organisms warm as they increase respiration

Some fish like the tunas actually can regulate and use

the heat liberated from their exercise to maintain body

temp.

Tunas have vast networks of blood vessels in their muscle

that can be constricted or dilated to increase blood

passage over muscle.

This allows tuna to heat their bodies in cold water or cool

them in warm waters.

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Ecomorphology

Ecomorphology - The study of how abiotic orbiotic factors influence the form orshape of an orga nism.

Any theory of species formation that fails to explain the intimate tie-up that exists between habitat and characters is atthe leastincomplete. Hubbs 1941

Example: Body shape types and swimming

Fusiform: idealized torpedo shape, lowest amountof drag (ex. Trout). Allows fast swimming/tolerance of flowing water.

Dorso-ventrally compressed: flattened on the back and belly (ex.Sturgeon, flounder, rays). Benthic species that lay on the bottomand/or use the current as a hydrofoil

Laterally compressed:flattened on the sides (ex. Centrarchids). Predators that need stability forattacks and maneuverability.

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Ecomorphology- Competing theories

Two competing theories of how ecomorphology works:

Natural selection weeds out unfit individuals and retains the fraction

of the population that best conforms to existing conditions.

OR

Ecological Polymorphism may allow members of a population to

avoid selective pressure by changing their shapes within a

morphologic space to match existing conditions. Plasticity

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Ecomorphology Important to understand what defines the grouping of individuals

1) Species are groups of actual or potential interbreeding natural populations which are reproductively

isolated from other groups (Mayr, 1963)

2) Sub-speciesor races are differentiable from species only in that they can occur with conspecifics yetmaintain their own specific genome and phenotype

3) Strains most likely arose from stocks, but have differentiated enough to display reproducible physiological,

morphological, or performance characteristics that are significantly different from other conspecifics

4) Stocks or sub-populations may arise or be present that partition themselves in response to both abiotic

and biotic factors or are simply isolated from each other

5) Population is defined as a group of organisms occupying a defined area that interbreed regularly and

maintain a randomly variable gene pool

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Ecomorphology: 5 Measurements

Measuring ecomorphometrics? (Chapt 7, 8, & 9 in Cailliet et al.)

Simple distance measurements

Meristic counts

Planar distortion (Truss Analysis)

Fineness Ratio

Performance Testing (relevance of differences measured)

Confounding factors

Sexual Dimorphism (males and females have different forms)

Allometric Growth (ratios and proportions change with size)

Condition (plumpness)

Reproductive changes (salmon, cyprinids; girth)

Natural latitudinal clines (strains - LMB)

Availability of historical collections Fixation and Preservation (shrinkage)

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Ecomorphology: Distance

Distance ratios

eye measurements: may relate to water clarity or mode

of feeding

head measurements: length may relate flow or feeding

fin lengths: related to flow and feeding mode

bone length: related to development period and habitat

mouth length (Gape): related to prey

intestine length: related to diet

brain length: different lobes proportional to their need

for use

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Ecomorphology: Merstics

Meristic Counts

Jordans Rule - latitudinal cline in number of a structure Pleomerism - number of a structure associated with size

Meristic counts can change in two ways

selection for or against a meristic characteristic

embryological development time

rarely - a mutation is incorporated into the population

meristic variation can be cause by:

temperature (vertebrae, fins)

diet (fin rays)

habitat (scale rows, number of scales) stress (all)

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Ecomorphology: Truss

Truss Analysis - a way to detect slight shape distortion in all directions of a 2-

dimensional plane

landmarks are chosen atdiscrete locations.

Points are individually measured or digitized to give Cartesian coordinates. All angles

and distances can be calculated from the Cartesian coordinates.

Data is analyzed using principal components analysis which creates new variables

based on combinations of the raw data to give values that represent dimensions of

shape. Individual length variation is accounted for by shearing first component

Components can be used to determine slight shape distortions between groups not

plainly visible to the naked eye or measurable with simple distances

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Ecomorphology: Fineness

Fineness ratio = L/D where L is standard length and D is greatest

body diameter.

Optimal FR is 4-5, but a range form 3-7 only results in a 10%change in drag.

Fineness Ratio is related to microhabitat and flow (Scarnecchia 88)

In areas where the flows are minimal and pool habitat is available or in

lakes, community-wide fineness ratios are low.

In areas where the flows are high and habitats are channelized,community-wide fineness ratios are high.

Importance: when habitats are modified and made more uniform,

species with certain fineness ratios are selected against. The result

is a decrease in species richness.

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Ecomorphology: Performance

Performance testing - the only way to validate the

significance of morphological differences is to test

performance. Is there and advantage or disadvantage)

associated with a particular form?

Laminar flow tube

Duration (how long they can last at flow X)

Tolerance (flow at which they can no longer maintain their

swimming)

Translocation experiments (plasticity test)

switch the hatching site eggs from two different groups

if parental characteristics are retained, genetic change has

occurred

if characteristics reverse, then habitat is deterministic and

ecomorphological polymorphism is the explanation: plasticity

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Ecomorphology: applications

Management Applications

Measurement of the effect of anthropogenic changes to habitat Differences which may give advantages to one group over another (Dont

stock riverine SMB in a small impoundment with lentic SMB)

Hypolimnetic effluent (COLD) from dams can cause developmental changesthat may be poorly adapted to warm water river reaches

Realization that certain habitat characteristics are a necessity, not just artifactof the environment for species (sturgeon and chubs need flow; sunfish cant

deal with flow very well.

Fields of biology that study ecomorphology Systematics - study of evolutionary & genetic relationships among organisms

Phenitics - The study of phenotype display and differences

Cladistics - study of sequential branching and relationship of similar species

Phylogentics - The study of the evolutionary lineage of an organism

Paleobiology - study fossils and how they fit into the evolutionary landscape

Genetics - The study of the molecular history and evolution of organisms