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Oceanography 101

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Chapter 14 - Animals in the Pelagic Environment

Chapter 14 handout #1
Chapter 14 handout #2

Feeding Frenzie videos
Anchovies in Santa Cruz:
Sharks along North Carolina beach
Sardines, dolphins, birds, sharks, whales:
Sei whale feeding:

General classifications of Living Things

Taxonomy is the system of classifying and naming organisms.
Carolus Linnaeus was first to development of a hierarchical system of classification of nature (biological organism, present and past) .
Today, this system includes seven taxa: kingdom, phylum, class, order, family, genus, and species. (These are constantly being split into additional taxa levels as discoveries are made. Look at the example of humans.

Example: Taxonomy of Humans
kingdom             kingdom: Animalia
  phylum           phylum: Chordata
(subphylum: vertebrata)
    class         class: Mammalia
(subclass: Theria)
(Infraclass: Eutheria)
      order       order: Primates
(suborder: Anthropoidea)
        family     (superfamily: Hominoidea)
family: Hominidae
          genus   Homo
            species sapiens

(Note: "Domain" has been added to apply to "superkindoms" subdivision status based largely on modern discoveries in microbiology - still under debate!)

a) Kingdoms of life

Monera - Bacteria/algae

- Forams/amoebas
Fungi - Mushrooms, molds

Plantea - Ferns, mosses, flowering plants (all are Autotrophs, photosynthetic)

- includes Invertebrates, Vertebrates (all are Heterotrophs)

2) Vertebrates - a large group of animals distinguished by the possession of a backbone or spinal column. They belong in the taxa:

* Phylum – chordate
* Subphylum – vertebrata

Lets look at the different classes in Vertabrata in the marine environment

Mammalia - Whales, seals, sea lions, otters, polar bears (mammals)
Amphibia - Frogs, salamanders (amphibians are rare in marine environments but a few species exist in "near marine" settings)
Reptilia - Snakes, turtles, lizards (crocodillians, iguanas)
Aves - Birds
Osteichthyes - Fish with bony skeletons
Chondrichthyes - Fish with cartilidge skeletons- sharks (very old fish with cartilage, some are up to 280 million years old)

Example of the taxonomy of "whales":

Example: Taxonomy of Whales
kingdom             kingdom: Animalia
  phylum           phylum: Chordata
(subphylum: vertebrata)
    class         class: Mammalia
      order       order: Cetacea
        family     Mysteceti (mustache whales)
Odontoceti (toothed whales)
Archeoceti (ancient whales - now extinct)
          genus   one or several genus within families
            species one or more species within a genus

Characteristics of All Marine Mammals
-- Land-dwelling ancestors
-- Warm-blooded
-- Breathe air
-- Hair/fur
-- Bear live young
-- Mammary glands for milk

Taxonomy of marine vertebrates include:

Order Carnivora (have prominent canine teeth)

-- Sea otters
(Family: Mustelidea)

-- Polar bears
(Family: Ursus)

-- Pinnipeds
---- Walruses
---- Seals
---- Sea lions
---- Fur seals

Order Sirenia (Herbivores living in coastal areas)
-- Manatees (tropical Atlantic Ocean)
-- Dugongs (Indian and western Pacific Oceans)

Order Cetacea
-- dolphins, porpoises, killer whales, toothed whales, and baleen whales
(have elongated skull with blowholes on top, use echolocation)
(emit clicks and get return, used to detect fish, can be used to stun fish)

---- Sperm whales use echolocation to hunt giant squid
---- Intelligence in Toothed Whales
(Large brains relative to body size; can communicate with each other, “trainable”)

Suborder Mysticeti: Baleen whales
- fibrous plates in whale mouths used to sieve prey items
-- Blue, Finback, Humpback, Gray, and Right whales

3) Invertebrates - "animals without backbones"
-- inhabit pelagic, benthic, and terestrial environments (more in Chapter 15)

Phylums of invertebrates
Protozoa - Single cell
Porifera - Sponges – filter feeders
Coelenterada - Coral, Jellyfish
Annelida - Worms
Mollusca - Bivalves, squid, octopus, gastropods (things with shells or large cavities)
Arthropoda - Crabs, shrimp and spiders
Echinodermata - Sea Stars, urchins and sea cucumbers (spiny skin)

Adaptations to the Marine Environment

-- Ability to float
(Zooplankton – some produce fats or oils to stay afloat)
-- Ability to swim
(Nekton – larger fish and marine mammals)

Propulsion and movement of fish -
the body plan of fish reflect adaptations to feeding on prey and fleeing predators.

Width/Length Ratio

Tuna - .28
Dolphin - .25
Swordfish - .24
Whale - .21 Most efficient is .25, but there is a scale factor
Ratio produced from natural selection “the fittest survive and produce offspring”

Compare with Surfboard Design!
Type Width Length Ratio Comments
SB 19 ¼ 6’4” 0.25 Small – med waves
PT 19 ¼ 6'7" 0.24 Large waves
Average LB 22" 9'0" 0.20 Like a whale – scale factor
Average SB 18 ¼" 6’2” 0.25 rapid turns, harder to control

Kinds of Zooplankton ("floaters and drifters")

Microscopic Zooplankton: Radiolarians, Foraminifers, Copepods

Macroscopic Zooplankton:
-- Krill ( resemble mini shrimp or large copepods, critical in Antarctic food chains)

-- Floating Macroscopic Zooplankton
---- Portuguese man-of-war (gas-filled float)
---- Jellyfish (soft, low-density bodies)

Swimming "Necton" Organisms (fish, squids, sea turtles and sea snakes, marine mammals)
-- Swim by trapping water and expelling it (squid, octopus)
-- Swim by curving body from front to back (fish, etc.)

Adaptations for Finding Prey

-- Lungers wait for prey and pounce (grouper).
-- Cruisers actively seek prey (tuna).

Adaptations to Avoid Predation
-- Speed
-- Hiding: includes Transparency, Camouflage and Countershading
-- Schooling (safety in numbers, appear as a larger unit, maneuvers confuse predators)
-- Poison (to touch or eat: examples: sea snakes, blowfish, lion fish)

Sea Snakes
- About 50 species
- Live in Indian and tropical west Pacific Oceans
- Very powerful venom
- Non aggressive, brightly colored, with small mouth and fangs
- 20 deaths per year from fishermen trying to remove them from nets