FishPredation: Difference between revisions
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- Christmas tree worms: filter water through tentacles sticking out homes in coral in order to capture plankton | - Christmas tree worms: filter water through tentacles sticking out homes in coral in order to capture plankton | ||
- giant clam: filter food from water | - giant clam: filter food from water | ||
<ref>Coral Reefs and Climate Change - What lives on a coral reef - Teach Ocean Science "Web. 2/25/2015 <http://www.teachoceanscience.net/teaching_resources/education_modules/coral_reefs_and_climate_change/what_lives_on_a_coral_reef<ref/> | <ref>Coral Reefs and Climate Change - What lives on a coral reef - Teach Ocean Science "Web. 2/25/2015 <http://www.teachoceanscience.net/teaching_resources/education_modules/coral_reefs_and_climate_change/what_lives_on_a_coral_reef <ref/> | ||
=== Suspension Feeders === | === Suspension Feeders === |
Revision as of 16:42, 25 February 2015
Fish Predation
Predation Model
- Energy vs. Cost
- Factors Affecting Search:
- For Predator: Hunger
- For Prey: Camouflage
- Factors Affecting Encounter
- For Predator: Swimming speed, water clarity, illumination, schooling, detection mechanisms
- For Prey: Morphology, activity level, pigmentation, distribution
- Factors Affecting Strike:
- For Predator: Alternative prey, location
- For Prey: Body size, sensory ability
- Factors Affecting Capture
- For Predator: Mouth gape, strike speed, handling
- For Prey: Escape capabilities, schooling, shelter seeking behavior [1]
Methods of Consuming Prey
Prey in an aquatic habitat are harder to capture than those on land due to the difference between the prey and the surrounding medium's density being lower in water; this causes the prey to be pushed away upon approach by a predator. For this reason, fish have developed a variety of methods to become successful predators in water. (need better source)
Suction
When a fish opens its mouth a pressure gradient is created that causes water (and whatever may be in that water) to flow into it. Fish make use of this as a way, called suction feeding, to capture prey.
Ram
To avoid propelling prey away, many fish use ram feeding. This is simply when the fish swims over the prey while its is mouth open. Tunas exhibit ram feeding in their predation methods.
http://www.biomechanics.ucr.edu/Higham%202011%20Fish%20Physiology.pdf
Pivot
Rather than translocate its whole body to reach prey, a predator may instead move only its head; this is called pivot feeding. Fish employing pivot feeding lift their entire head (including the mouth) to close the gap between it and the prey. It is much slower to accelerate a fish's whole body than just its head in order to close in on near by prey. Pipefishes often use this method of approaching prey. A lounger snout allows for faster approach of prey with just the turning of the head than a shorter snout; due possibly to this, it has been observed that longer-snouted pipefishes tend to feed on more agile prey than their shorter-snouted counterparts.
http://rsif.royalsocietypublishing.org/content/4/14/561#sec-13
Jaw Protrusion
Another way to get close to prey without moving the entire body is jaw protrusion. Here the fish extends its upper jaw in order to close the distance between its mouth and prey so suction feeding can be utilized. Further, this adaptation can increase the total force exerted on prey up to 35%. The slingjaw wrasse uses this mechanism for feeding.
- Spotted Grouper: slow sped so creats a vacuum, inhaling victim near its mouth, swallow live prey - Anglesfish - some have protruding mouth for reaching prey withing small crevices in reef
Filter
- capture prey by pumping water through filtration structures - zooplankton, bivalves, sponges, tunicates - Christmas tree worms: filter water through tentacles sticking out homes in coral in order to capture plankton - giant clam: filter food from water
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Size is the most important factor in determining predation rates. For example, there is a decreasing rate of predation with jellyfish as fish larvae size increases. One fish that is commonly found in the Caribbean, the porcupine fish, inflates its body in order to increase its size, therefore decreasing the predators that would be capable of eating it. Predators would have to have a larger jaw in order to eat the porcupine fish. Predation occurs at all sizes of organisms. Microscopic organisms are predators, and so are large whales. The highest rates of predation occur on juvenile fish. This is because predation is most common during life transitions. After fish larvae hatch, the are more susceptible to predators. Fish are also susceptible to predators at another life transition - during mating. [4] Most fish are active either during the day or at night, not 24 hours. Their diurnal or nocturnal feeding is normally fixed genetically.[5]
Importance of Predation
Food Web
Predators help keep the food web in-check. Food webs are divided by trophic levels. Top predators have a “trophic cascade” effect on food webs - having a top-down effect on lower trophic levels. The elimination of predators can cause serious perturbations to an ecosystem. [1]
Important Evolutionary Force
Predation is a strong force of natural selection. The weaker species is eliminated. Fish predation is an important evolutionary force because when certain types of fish are targeted by predators they do not have as great of a survival rate. They are forced to acclimate, and as numbers dwindle and the more advantageous fish win out, and the fish population will evolve over time. [1]
References
- ↑ 1.0 1.1 1.2 1.3 K.M. Bailey, JT. Duffy Anderson. 2001. Fish Predation and Mortality. Encyclopedia of Ocean Sciences (Second Edition). Pages 417-421.
- ↑ Filter and suspension feeders "Web. 2/25/2015 <http://www.coralscience.org/main/articles/aquaculture-a-husbandry-4/filter-feeders
- ↑ Amsel, Sheri. “Food Webs.” Coral Reef Food Web. Exploring Nature Educational Resource. © 2005 - 2014. April 14, 2014. <http://exploringnature.org/db/detail.php?dbID=2&detID=1221
- ↑ Hixon, Mark A. 1991. Predation as a Process Structuring Coral Reef Communities.Oregon State University Publishing. http://hixon.science.oregonstate.edu/files/hixon/publications/026%20-%20Hixon%2091%20Sale%20book.pdf
- ↑ Houlihan, Dominic. 2001. Food Intake in Fish. Blackwell Science. Pages 189-209.