Giant Pacific Octopus Rachel Kamradt - PowerPoint Presentation

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Giant Pacific Octopus

Rachel Kamradt

Enteroctopus

dofleini

TaxonomyHabitat and densDiet and feeding behaviorPredatorsSize and camouflage IntelligenceMating and reproductionLifespanPopulation StatusHuman ImpactFishery?

Preview

Kingdom: AnimaliaHeterotrophicMust feed on outside sourceMulticellular Produce sexuallyPhylum: MolluskaBilateral symmetrySoft bodyNervous system, circulatory system; pair of gills and kidneys

Taxonomy

Class: Cephalopoda “head foot”Flexible armsClosed circulatory systemSiphonShell divided by septaLarge brain with ganglia in craniumSubclass: ColeoideaInternal shell greatly reduced in size or non-existant

Order: OctopodaEight armsRounded bodyNo shellSuborder: IncirrataNo finsFamily: OctopodidaeSuckers in groups of one or twoStomach and caecum follow digestive glandLateral teeth on their radulas Teeth only have one cuspMales third arm modified into a hectocotylus

Genus: Enteroctopus“Giant octopus”Large bodies with longitudinal wrinkles or foldsSpecies: Dofleini

Inhabits the Northern Pacific waters -Off coast of Southern California -North along Pacific coastline of the US -Across the Aleutians and South to JapanIntertidal to at least 2500 feetBenthic

Habitat

Enjoy spending their time in areas under rock cover where they can easily camouflage. Often create, or choose, a den that has many entrances. Rarely lives in a single den for longer than one month. Except a femalewith her eggs. Dens left uninhabited are frequently moved into byother giant octopuses. They then live there for another short period of time. 

Dens

Hunt at nightNewly hatched octopuses eat larval crabs and seastarsAdults feed on mostly crustaceans and mollusks -most often crabs and scallops -also other bivalves, snails, fish, sharks, and other octopuses

Diet

3 techniques when feeding

1. Pull it apart with their arms 2. Bite it open with their beak 3. ‘Drill’ through the shell -secretes saliva to soften the shell -softened material is scraped away with the radula to create a small hole -toxin is secreted through the holeDiscards eaten shells into a garbage pile, called a Midden, just outside the den.

Feeding Behavior

Their beak is the only hard part of their body.Any opening that is large enough for their beak to fit through, they can squish the rest of their body to fit through.

Beak

Many young octopuses (under 10 pounds) are lost to predators. -seals, lingcod, sea otters, mink, diving birds, other octopusesOnly the largest fish (such as halibut) and marine mammals are any threat to adults.Humans collect the giant Pacific octopus for food, for display in aquariums, and for use as bait in other fisheries.

Predators

This is the second largest species of octopus.The record holder: 600 pounds, 30 feetMost weigh about 50-90 pounds, 15 feet

Size

Reflects mood: white for fear, red for anger, brown is the usual color. Color and texture change is initiated in the eyesSpecial pigment cells (chromatophores) will activate when disturbedChromatophores consist of 3 bags containing different colors. -adjusted individually until background is matched.

Colors

Highly intelligent creatures. They have learned to open jars, mimic other octopuses, and solve mazes in lab tests. Most complex brain if the invertebratesLong-term and short-term memoryLearn to solve problems by trial and errorRemember solutions, can solve similar problems

Intelligence

Female finds a male typically bigger than herselfHead for a den in deeper waterThird right arm of a male is modifiedHectocotylized Modified tip: ligulaUsed for mating1/5 the length of the arm

Mating

About a month after matingFemales lay eggs in a rocky den20,000-100,000 over several daysHangs from roof of the den in strands (250 each)Tended to and cleaned until hatchedMother shoots streams of oxygen and nutrient rich water over them150 days- 7 or more months (depends on temperature)Females do not feedduring this time, and die shortly after

Reproduction

3-5 years old

Both males and females dying soon after breeding. Hatches from an egg the size of a grain of rice -Hatchlings just over ¼ in. long -Weigh 22 milligrams -About 14 tiny suckers each legDrift in surface waters eating plankton for about 3 months -then settle on seafloor weighing about 5 gramsA year later about 20 pounds, and able to breed

Lifespan

Larger specimens (over 100 pounds) are seldom seen. Live short lives and produce lots of eggs- fairly resilient Not as heavily fished as other seafoodPopulation in relatively good shape

Population Status

Commercially fished in both North America and Japan -For food and bait for species like Pacific HalibutPopular in Asian and Mediterranean cuisineRecords show up to 3,500 tons caught per year in just North America

Human Impact

Examined 4 pot types for capture1. Sablefish PotsRebar, baited with Herring2. Korean Hair Crab PotsPVC piping, baited with Herring3. Shrimp PotsBaited with Herring or Prawn pellets4. Kodiak Wooden Lair PotConstructed of wood, left unbaitedResults:Highest in Sablefish and Lair potsSablefish caught heavier octopusBut had high rates of bycatch

Octopus Fishery? (Barry)

Giant Pacific Octopus. (n.d.). Retrieved November 2, 2014, from http://www.montereybayaquarium.org/animal guide/octopus-and-kin/giant-pacific-octopusNorth Pacific Giant Octopus. (n.d.). Retrieved November 2, 2014, from http://www.arkive.org/north-pacific-giant-octopus/enteroctopus dofleini/Enteroctopus dofleini (Wulker, 1910). (2005, January 1). Retrieved from http://www.wallawalla.edu/academics/departments/biology/rosario/in verts/Mollusca/Cephalopoda/Enteroctopus_dofleini.htmlBarry, P., Tamone, S., & Tallmon, D. (2012). Evaluation of the capture efficiency and size selectivity of four pot types in the prospective fishery for North Pacific giant octopus (Enteroctopus dofleini). Fishery Bulletin, 108(1), 39-44. Retrieved November 10, 2014, from http://fishbull.noaa.gov/1081/barry.pdf

Works Cited