FishPredation
Aquatic 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]
Other Feeding Factors
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]
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
Fish opens its mouth and rapidly expands its oral cavity, thus creating a negative pressure. When the mouth is opened, water rushes in, drawing in the prey item from a distance. This is a common feeding technique of sharks (like the Nurse Shark), rays, and other fish (e.g. the Atlantic Guitarfish). [6] [7]
Ram
The fish swims over the prey while its is mouth open. Often used in adjunct with suction feeding technique. Ram feeders overtake the prey with body swift movements, and finish the attack with an explosive strike of suction feeding. At the very least, some compensatory suction is needed to eliminate the bow wave formed as the fish swim toward the prey. Tunas exhibit ram feeding in their predation methods. [8] The Great Barracuda is another fish that commonly employs this strategy. [9]
Pivot
Rather than translocate its whole body to reach prey, a predator may instead move only its head. 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.[10]
Example: Harlequin Pipefish
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%.
- Spotted Grouper: slow speed so creates a vacuum, inhaling victim near its mouth, swallow live prey [11] - Anglefish - some have protruding mouth for reaching prey withing small crevices in reef
Filter
Capture prey by pumping water through filtration structures. Method is seen in variety of species in zooplankton, bivalves, sponges, tunicates.
Example:
- Christmas tree worms: filter water through tentacles sticking out homes in coral in order to capture plankton
- giant clam: filter food from water
Suspension Feeders
In this scheme, the predator actively captures nearby prey by using tentacles. This method is not entirely passive, some modify arm and pinnule postures to take best advantage of prevailing and changing flow patterns and velocities. This method is used by species throughout octocorals, crinoids, scleractinian corals. [14] The feather star is a common example of this feeding tactic. [15]
Physiological adaptations
Some coral reef predators develop physical traits evolved for a more advantageous and specialized predatory technique. An example is the parrot fish: it has beak like jaws for scraping algae off coral and teeth for grinding coral. [16]
Manipulation
Another means of capturing prey is by making physical contact with them and transporting them to the mouth. An example of this would be biting, which is used by sharks. [17] Another common example is the butterflyfish's technique of gripping a removing pieces from polychates, nemertean, corals, ascidians, echinoids, hydroids and other prey that attach themselves to hard substrate. [18] However, this form of predation is not limited to jawed fishes. Hagfishes and lampreys use teeth attached to dental plates that are extended and retracted during feeding, this pulls the prey into its mouth. Jawless fish can transmit the most force possible with this method but it does not allow for the faster feeding that allowed jawed fishes to become evolutionarily successful. [19]
Predation strategies
Cleaner Fish
- mutualism
- feed off dead skin and ectoparasites on other fish
- examples: wrasse, cichlids, gobies
Mimicry[20]
- motion, coloration, morphology
- resemble harmless species in order to attack prey
- aggressive mimicry
- facultative mimicry - abilirt ot switch between mimic and non-mimic colours
- mimic animate and inanimate objects in reefs
- non-cleaner fish mimic cleaner fish, feeding off scales and tissue
Triggerfish [21]
- dig out crabs and worms by flapping away debris with fins and sandblasting with water squirted from mouth
- smaller fish feed on leftovers
- "trigger" spine "unlocks" set of spines
camouflage
- use of color, appendages, irregularities in body
- examples: scorpionfish, frogfish [22]
ambush...
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.
- ↑ A. D. Nunn, L. H. Tewson, and I. G. Cowx. The foraging ecology of larval and juvenile fishes. Hull International Fisheries Institute, Department of Biological Sciences, University of Hull, Hull, HU6 7RX, UK. Published online: 26 October 2011
- ↑ 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.
- ↑ http://www.mapoflife.org/topics/topic_401_Suction-feeding-in-fish-amphibians-reptiles-and-aquatic-mammals/
- ↑ http://www.ncbi.nlm.nih.gov/pubmed/9808831
- ↑ http://fishlab.ucdavis.edu/ReefFishFeeding.pdf
- ↑ http://www.academia.edu/599465/Feeding_biomechanics_in_the_Great_Barracuda_during_ontogeny
- ↑ http://rsif.royalsocietypublishing.org/content/4/14/561#sec-13
- ↑ No Title "Web. 2/25/2015 <http://www.miamisci.org/oceans/coralreef/predators/2grouper.html
- ↑ Filter and suspension feeders "Web. 2/25/2015 <http://www.coralscience.org/main/articles/aquaculture-a-husbandry-4/filter-feeders
- ↑ 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
- ↑ http://www.coralscience.org/main/articles/aquaculture-a-husbandry-4/filter-feeders
- ↑ http://www.nova.edu/ocean/messing/crinoids/8%20Feeding%20mechanism.html
- ↑ No Title "Web. 2/25/2015 <http://www.miamisci.org/oceans/coralreef/predators/5parrotfish.htm
- ↑ http://www.biomechanics.ucr.edu/Higham%202011%20Fish%20Physiology.pdf
- ↑ http://fishlab.ucdavis.edu/F-G%20et%20al%20JEMBE%2001.pdf
- ↑ http://www.biomechanics.ucr.edu/Higham%202011%20Fish%20Physiology.pdf
- ↑ Visual Biology & Mimicry - Coral Reef Systems Multimedia." Visual Biology & Mimicry - Coral Reef Systems Multimedia. N.p., n.d. Web. 25 Feb. 2015.
- ↑ Triggerfish, Triggerfish Pictures, Triggerfish Facts -- National Geographic." National Geographic. N.p., n.d. Web. 25 Feb. 2015.
- ↑ Camouflage among Pacific and Red Sea Coral Reef Creatures." Camouflage among Pacific and Red Sea Coral Reef Creatures. N.p., n.d. Web. 25 Feb. 2015