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OUR OCEAN PLANET

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Title: OUR OCEAN PLANET


1
OUR OCEAN PLANET
  • OUR OCEAN PLANET
  • SECTION 6 TEMPERATE SEAS

2
REVISION HISTORY
Date Version Revised By Description
Aug 25, 2010 0.0 VL Original
3
6. TEMPERATE SEAS
6. TEMPERATE SEAS
4
6. TEMPERATE SEAS
  • Temperate seas lie between the tropics and the
    polar regions. These are cool green waters that
    are highly productive and immensely rich in
    algae, plant, and animal life.
  • Summers are warm and winters cold but there is
    rarely permanent sea ice in temperate waters.
    Water temperatures range from 4C-20C
    (39F-68F).
  • The algae and plant life that makes these seas
    green comes from chlorophyll found in several
    organisms namely
  • 1. Plankton
  • Phytoplankton plant and algae plankton
  • Zooplankton animal plankton
  • 2. Marine Algae/Seaweeds
  • Green
  • Brown
  • Red
  • The rich algae and plant life base gives rise to
    large numbers of zooplankton (e.g. copepods),
    herbivorous invertebrates (such as sea urchins
    and molluscs), and herbivorous fish. These
    primary consumers are preyed upon by other
    invertebrates (e.g. jellyfish, horseshoe crabs),
    fishes (e.g. sturgeons), birds, and mammals (e.g.
    sea otters and sea lions).

5
6. TEMPERATE SEAS
6
6.1 PLANKTON
6.1 PLANKTON
7
6.1 PLANKTON
6.1 PLANKTON Plankton is a general term used to
refer to a variety of tiny animals and plants
that are found drifting about in the ocean.
There are two main types of plankton, namely,
phytoplankton (plant plankton) and zooplankton
(animal plankton). They are usually microscopic
in size although some can be quite large (a
couple of meters in diameter). Each year,
between spring and autumn, plankton numbers
increase dramatically to form huge populations.
These planktonic blooms are critical to vast
numbers of invertebrates, fish, birds and
mammals, since plankton is one of the most
fundamental and important sources of food in the
ocean. 6.1.1 Phytoplankton Phytoplankton (plant
plankton) can use sunlight to transform carbon
dioxide and water into carbohydrates through a
process called photosynthesis. Phytoplankton
are, therefore, producers and form the base of
the oceans food chain. There are several types
of phytoplankton varying greatly in size and
shape
8
6.1 PLANKTON
1. Cyanobacteria Cyanobacteria are the smallest
of the phytoplankton and are tiny single-celled
organisms that have blue and green pigments.
This gives them their common name the
blue-green bacteria or blue-green algae. 2.
Diatoms Diatoms are beautiful single-celled algae
with two glass-like halves and spines and ribs
radiating from them. There are over 6,000
species of diatoms, and they are often the most
numerous phytoplankton in temperate waters. 3.
Dinoflagellates The dinoflagellates have both
plant and animal characteristics in that they are
able to photosynthesize food (like plants) but
can also move using flagella (like animals).
Their bodies are made of cellulose and they can
produce bioluminescent light. 4.
Protozoans Protozoans are single-celled animals.
However, some protozoans contain symbiotic algae
which are able to photosynthesize food.
Protozoans such as foramniferans have shells made
of calcium carbonate while radiolarians have
shells made of silica.
Important! Each year, 6 billion tonnes of microscopic algae, such as diatoms, grow in the worlds oceans producing nearly 50 of the worlds oxygen a by-product of photosynthesis.
9
6.1 PLANKTON
REFERENCES FURTHER READING Byatt, Andrew,
Fothergill, Alastair and Holmes, Martha, The Blue
Planet Seas of Life, Chapter 4, DK Publishing
Inc., (2001), ISBN 0-7894-8265-7
Interesting! The word plankton comes from the Greek word planktos which means drifter or wanderer.
10
6.1 PLANKTON
6.1.2 Zooplankton Zooplankton (animal plankton)
feed on phytoplankton or other zooplankton.
There are several types of zooplankton,
namely 1. Copepods Copepods ("oar feet") are
small, shrimp-like crustaceans with T-shaped
antennae that swim in seas, lakes and ponds.
These are the primary consumers of phytoplankton.
They have a hard exoskeleton, legs for swimming
and gathering food, a segmented body, and jointed
appendages. Most copepods are less than 1 mm
(0.04 in) long but a few oceanic species are over
1 cm (0.25 in) long. These arthropods have one
simple eye in the middle of the head which can
only differentiate between light and dark. There
are two pairs of antennae one pair is long and
one pair is short. Female copepods produce
clusters of eggs that she carries in one or two
egg sacs that are attached to her abdomen. Like
all crustaceans, copepods molt their exoskeleton
as they grow. There are 10 orders and over 4,500
species of copepod. A few orders are
free-swimming (using their legs) but many are
parasites (of fish). Copepods are adept at
catching and eating phytoplankton including
cyanobacteria, diatoms and other tiny,
single-celled organisms in the water. Maxillae,
maxillipeds and antennae push food towards the
mandibles (jaws) for processing.
Important! Copepods are probably the most numerous animal on the planet forming 70 of the total zooplankton.
Interesting! The collective name for a group of plankton is a swarm.
11
6.1 PLANKTON
Free-swimming copepods are a component of
zooplankton and are very important in the food
web since many animals feed on them including
mussels, fish and fish larvae, squid, sea birds,
and mammals (such as baleen whales and certain
seals). 2. Meroplankton Meroplankton is the
collective name for the tiny eggs and larvae of
animals that spend part of their life in the
plankton before maturing. In summer, the sea
will be full of eggs, larvae and young
invertebrates. The young of crustaceans (e.g.
crabs, lobsters shrimps), echinoderms (sea
urchins sea stars), molluscs, and fish are
among the huge variety of organisms that spend
their first weeks of life as plankton. Many
meroplankton are herbivores. In time, they will
change in appearance and, if the larvae are
fortunate, they will survive to adulthood. 3.
Cnidarian Larvae Other zooplankton include
free-swimming cnidarians such as jellyfish. For
example, moon jellyfish primarily feed on
copepods and can consume thousands in a day.
These jellyfish form swarms so dense that the
water can appear pinkish-white from the air. In
contrast, lions mane jellyfish feed on copepods,
meroplankton, other jellyfish, and fish, but do
not tend to form swarms. Zooplankton is, in
turn, preyed upon by other animals, ranging from
other invertebrates and small fish to the giants
including planktivorous sharks (e.g. whale and
basking sharks) and baleen whales (e.g. humpback
and blue whales). REFERENCES FURTHER
READING http//museumvictoria.com.au/crust/copbiol
.html - Copepods http//en.wikipedia.org/wiki/Plan
kton - Plankton http//www.enchantedlearning.com/s
ubjects/invertebrates/crustacean/Copepod.shtml -
Copepods
12
6.2 MARINE ALGAE / SEAWEED
6.2 MARINE ALGAE / SEAWEED
13
6.2 MARINE ALGAE / SEAWEED
6.2 MARINE ALGAE / SEAWEED Seaweeds are marine
algae and, although they are found virtually
worldwide, most of the worlds 10,000 species of
seaweed exist in temperate water. The smallest
can be planktonic or found growing in sand or
inside an animals shell or body. The most
familiar, however, are probably the large
seaweeds which are often found on rocky coasts
firmly attached to a hard stable substrate. At
the base of the seaweed is a clump of entwined
growths, called a holdfast, which anchors the
seaweed to the substrate. From the holdfast, a
long stem called a stipe extends upwards which
supports a series of leaf-like fronds (or
blades) in which most photosynthesis occurs.
In the largest seaweeds, the fronds are buoyed by
gas-filled bladders called pneumatocysts. The
specific colours and forms of seaweed depend on
their habitats and combination of pigments.
Generally, however, there are three types of
marine algae green, brown and red. 1. Green
Algae Green algae get their colour from the green
pigment chlorophyll. They are about 6,000
species of green algae but most are not found in
the ocean. The marine species are commonly found
in temperate rock-pools. They are generally
small and many are filamentous resembling thin
green hair. One of the most common is sea
lettuce, which is found in rock-pools and around
the bases of larger seaweeds. Sea lettuce is
often eaten by small invertebrates.
14
6.2 MARINE ALGAE / SEAWEED
2. Brown Algae There are about 1,500 species of
brown algae varying from yellowish to deep brown.
They range from simple filamentous algae to the
largest seaweed of all the giant kelp
(Macrocystis spp.) which may grow to more than 45
m (150 ft) in length. Although giant kelp
superficially resembles a tree, it is quite
different. For example, kelp has no roots. Kelp
does anchor itself to the bottom of the ocean
floor but the anchoring system (holdfast) does
not take in nutrients from the soil like plant
roots do. The stipe and blades of the kelp are
very flexible and cannot stand upright unaided.
As a result, kelp has tiny air bladders at the
base of each blade to help it float and grow
toward the surface of the water where sunlight is
most plentiful. 3. Red Algae Red algae are the
most numerous of the marine algae and consist of
about 4,000 species. They contain chlorophyll
but the green colour is masked by a red pigment
called phycobilin. They are usually small and
tissue-like, and encrust rock pools or grow on
larger brown seaweed stipes. They can be a
variety of colours from pink to purple. Some red
algae deposit thick calcium carbonate (the same
material coral is made from) around their cells
walls. These coralline red algae are tough
enough to grow in the rocky surf zone.
Interesting! Seaweed is an integral part of human life. Kelp, sea lettuces and red algae are dried, steamed, and cooked in a variety of dishes. The thin black sheets covering rice and raw fish in sushi is made from red algae Porphyra. Alginates from brown seaweed are used to give ice cream its smooth texture. Agar, from red algae, is used in cake icings, as a clarifying agent for beer and as a growth medium for micro-organisms studied by scientists.
15
6.2 MARINE ALGAE / SEAWEED
6.2.1 Kelp Forests Kelp provides the physical
substrate and habitat around which kelp forest
communities are built. Organisms supported by
kelp forests include sea urchins, sea stars, sea
anemones, clams, and tunicates. These organisms
are preyed upon by larger animals such as fish
and octopuses. Sea otters and sea lions also eat
sea urchins, clams and octopuses. These mammals
may, in turn, be preyed upon by large sharks,
such as the great white shark. Kelp forest
ecology studies focus on understanding bottom-up
and top-down trophic processes the
relationships between organisms and their place
in the food chain. Bottom-up processes are
generally driven by abiotic conditions required
for primary producers to grow (such as the
availability of light and nutrients). For
example, the occurrence of kelp is frequently
related to oceanic upwelling zones which provide
unusually high concentrations of nutrients to the
local environment. This allows kelp to grow and
support herbivores which, in turn, support
consumers at higher trophic levels. In contrast,
top-down processes are those in which predators
limit lower level prey species through feeding on
them. In the absence of predation, the lower
level species would flourish. For example, in
Alaskan kelp forests, sea otters control
populations of herbivorous sea urchins through
predation. When sea otters are removed from the
ecosystem (for example, by human activity), sea
urchin populations are released from predatory
control and grow dramatically. This leads to
increased herbivore pressure on local kelp stands.
16
6.2 MARINE ALGAE / SEAWEED
Deterioration of the kelp itself results in the
loss of the physical ecosystem structure and
subsequently, the loss of other species
associated with this habitat. In Alaskan kelp
forest ecosystems, sea otters are the keystone
species that mediate this trophic cascade. In
Southern California, kelp forests persist without
sea otters and the control of herbivorous sea
urchins is instead mediated by other predators
including lobsters and large fishes. The effect
of removing one predatory species in this system
differs from Alaska because there are other
predators that can continue to regulate sea
urchins. However, the removal of multiple
predators can effectively release sea urchins
from predator pressure and allow kelp forest
degradation. While sea urchins are usually the
dominant herbivore, others include sea stars,
isopods, kelp crabs, and herbivorous fishes. In
many cases, these organisms feed on kelp that has
been dislodged from substrate and drifts near the
ocean floor. If there is enough drift kelp,
herbivorous grazers do not exert pressure on
attached plants. Many studies in Southern
California have demonstrated that the
availability of drift kelp specifically
influences the foraging behavior of sea urchins.
Drift kelp and kelp-derived particulate matter
have also been important in subsidizing adjacent
habitats, such as sandy beaches and the rocky
inter-tidal areas. REFERENCES FURTHER
READING http//www.nmnh.si.edu/botany/projects/alg
ae/classification.htm - Algae http//www.usc.edu/o
rg/seagrant/Education/Kelp/WhatIs.html - What is
kelp? http//en.wikipedia.org/wiki/Kelp_forest -
Kelp forest http//www.amonline.net.au/factsheets/
kelp.htm - Kelp fact sheet http//news.nationalgeo
graphic.com/news/2006/09/060906-octopus-video.html
- octopus/shark Byatt, Andrew, Fothergill,
Alastair and Holmes, Martha, The Blue Planet
Seas of Life, Chapter 4, DK Publishing Inc.,
(2001), ISBN 0-7894-8265-7
17
6.2 MARINE ALGAE / SEAWEED
6.2.2 Kelp Forest Life
18
6.2 MARINE ALGAE / SEAWEED
KELP Kelp is a brown seaweed. Perhaps the most
widely-recognized species are the giant kelps
(Macrocystis spp.) although there are numerous
other types. Macrocystis pyrifera grows to over
45 m (150 ft) long. The stipes (or stems) are
unbranched and each has a gas bladder at its
base. When a large number of giant kelp grows
together, as they do off the coast of California,
they are collectively known as a kelp forest.
SEA OTTER Sea otters are long, sleek and furry
marine mammals. They are the largest member of
the weasel family and are about 1.2-1.5 m (4-5
ft) in length and weigh 20-45 kg (45-100 lbs).
Sea otters have webbed hind feet and smaller
front feet. They eat a variety of invertebrates
including crustaceans (crabs, lobsters and
shrimps), bivalves (clams, mussels and abalone)
and echinoderms (sea urchins and sea stars).
They also eat octopus, squid and fish.
Underneath each front arm is a pouch of loose
skin that temporarily stores food and rocks
collected during dives. Floating on their backs,
sea otters rinse and hammer open prey with a rock
they keep in their pouch. They are the only
mammal (besides primates) known to use tools.
19
6.2 MARINE ALGAE / SEAWEED
CALIFORNIA SEA LION California sea lions have a
pair of small external ears. They swim using
their fore-flippers like oars while their hind
flippers are not used. On land, their hind
flippers can be turned forward under body and
used for movement. There are about 160,000
California sea lions and they are found off the
coasts of California, Mexico and the Galapagos
islands. They eat fish and molluscs (e.g.
octopus and squid). GREAT WHITE SHARK The great
white shark is considered a large and dangerous
shark. They spend much of their life in the open
ocean but will move into coastal waters
seasonally to hunt for sea lions and seals. It
has a heavy body, large head, and pointed snout,
with large triangular teeth with serrated edges.
Its body is slate blue or leaden grey above and
dirty white below. It can reach a length of 7.9
m (26 ft) but is usually less than 4.9 m (16 ft).
The great white shark is a member of the
Mackerel Shark family and was probably made
infamous through the movie Jaws.
20
6.2 MARINE ALGAE / SEAWEED
OCTOPUS The octopus is a cephalopod (an unshelled
mollusc) that inhabits several different ocean
habitats. Octopuses are characterized by their
eight arms (not tentacles) which usually have
suction cups on them. Unlike most other
cephalopods, the majority of octopuses have
almost entirely soft bodies with no internal
skeleton. They have neither a protective outer
shell (like the nautilus) nor any vestige of an
internal shell or bones, (like cuttlefish or
squids). A beak, similar in shape to a parrot's
beak, is the only hard part of their body. As a
result, an octopus can squeeze between narrow
crevices. This is very useful when it is hiding
from morays or other predators. SEA ANEMONE Sea
anemones are simple animals (cnidarians) that are
often attached to the sea bottom. Sea anemones
have cylindrical bodies that are surrounded by
upward-facing tentacles. The tentacles have
stinging cells on them which kill prey and move
the food into a sea anemones mouth. The mouth
leads into the body cavity which digests the
food. A continuous current of water through the
mouth circulates through the body cavity and
removes waste. Sea anemones are found in cold
and warm waters. Many are colourful, and large
species can be 1 m (3 ft) in diameter.
21
6.2 MARINE ALGAE / SEAWEED
SEA STAR Sea stars (or starfish) are soft-bodied
marine animals with five arms. Sea stars are
echinoderms, a large group of invertebrates which
include sea urchins, sand dollars, sea cucumbers
and brittle stars. Sea stars typically live in
the middle of a tidal range and can survive short
periods of exposure to air as the tide
retreats. SEA URCHIN Sea urchins are
echinoderms. They are round, spiny and
herbivorous invertebrates that graze on algae and
detritus from grass beds and rocky areas. Many
sea urchins have long, sharp spines on their
backs, which protect them from predators such as
fish, crabs, moray eels and sea otters. However,
their underside is often spineless and they are
vulnerable to attack from that side if the
predator can turn the sea urchin over.
22
6.3 OCEAN LIFE
6.3 OCEAN LIFE
23
6.3 OCEAN LIFE
6.3 OCEAN LIFE 6.3.1 Horseshoe
Crabs DESCRIPTION Horseshoe crabs are an ancient
species of invertebrates related to the
trilobites. They are regarded as living fossils
since they have stayed unchanged for more than
350 million years. Horseshoe crabs are not, in
fact, true crabs (crustaceans) and are more
closely related to spiders scorpions
(arachnids). CHARACTERISTICS Horseshoe crabs
have a hard chitin-based exoskeleton with 3
segments prosoma (head), opisthosoma (abdomen)
and telson (tail). They have 10 eyes, 5 pairs of
jointed, pincered, walking legs and 1 pair of
feeding pincers (chelicerae). They have
light-blue, copper-based blood and breathe
through book gills (thin plates located on
abdomen). SIZE Males are 18-23 cm (7-9 in)
across the prosoma and 33-41 cm (13-16 in) in
length (head to tip of tail). Females are
typically 30 larger than males and are 23-31 cm
(9-12 in) across the prosoma 41-51 cm (16-20
in) in length (head to tip of tail).
24
6.3 OCEAN LIFE
LIFESPAN Horseshoe crabs take 8-10 years to reach
adulthood and their lifespan is 20-30
years. DIET Horseshoe crabs eat worms, mollusks
and dead fish. They find prey along the sea bed
and use their chelicerae to find push food into
their mouths. REPRODUCTION In winter, horseshoe
crabs move offshore and hibernate half-buried in
ocean sediments. In spring, they move towards
beaches to reproduce. A male hooks onto a female
using his first pair of walking legs
(pedipalps) remains attached to her. The
female then scoops out a shallow nest in the sand
and lays 3,000 to 20,000 small jade-green eggs
about 20 cm (8 in) into the sand. The male then
fertilizes the eggs as she drags him over them.
Young horseshoe crabs hatch in about 1 month.
The mating season lasts from April through
December. DISTRIBUTION Horseshoe crabs are found
off the coasts of Japan, Hong Kong, Indonesia,
the eastern USA (e.g. ME, NY, NJ DE) and the
Gulf of Mexico.
25
6.3 OCEAN LIFE
USES Horseshoe crabs have several uses in
medicine. An extract of horseshoe crab blood
Limulus amoebocyte lysate (LAL) is used to
ensure biomedical products (e.g. vaccines) are
free of bacterial contamination. Horseshoe crab
chitin is used in manufacturing chitin-coated
suturing filament and wound dressing for burn
victims. THREATS Horseshoe crabs are threatened
by shoreline development and habitat loss,
pollution, their use as bait by conch eel
fisheries, and for their blood and chitin by the
biomedical industry. SPECIES Today, there are 4
species worldwide. Limulus polyphemus is found
in the Northwest Atlantic Ocean, the other three
are found in the Far East. INTERESTING
FACTS Have light-blue, copper-based blood (unlike
humans, which have red, iron-based blood) Very
important animals from a human perspective as
they have several uses in medicine Host to
numerous parasites barnacles, blue mussels,
slipper shells, bryozoans, sponges Although
horseshoe crabs look formidable, they are
harmless and do not use their pointed tail as a
weapon but only to right themselves when they are
turned over. Horseshoe crabs are not true crabs
actually quite different in spite of general
resemblance
26
6.3 OCEAN LIFE
Horseshoe Crabs True Crabs
No antennae No mandibles Multiple un-stalked eyes Moult by walking forward out of their shell Have antennae 1 pair of mandibles Stalked eyes True crabs back out of their shell when malting
12 legs (6 pairs) including 6 pairs of claws 1st pair (chelicerae) for feeding 2nd pair (pedipalps) differentiate gender Remaining pairs are walking legs 10 legs (5 pairs) including 1 pair of claws
REFERENCES FURTHER READING http//www.horseshoec
rab.org/ All about the horseshoe crab natural
history, anatomy, conservation current
research http//www.ocean.udel.edu/horseshoecrab/i
ndex.html University of Delaware Sea Grant
College Program http//www.dnr.state.md.us/educati
on/horseshoecrab/ Maryland Department of Natural
Resources
27
6.3 OCEAN LIFE
  • 6.3.2 Sturgeons
  • DESCRIPTION
  • Large, primitive, bony fish
  • Skeleton has large proportion of cartilage
  • Head bony
  • Long snout with a row of 4 barbels in front of
    mouth
  • Mouth ventral and protrusible
  • Adults have no teeth
  • May have a spiracle above and behind eye
  • 1 dorsal fin set far back
  • Large bony plates (scutes) on body
  • Heterocercal caudal fin (upper lobe longer than
    lower lobe)
  • Long lived 50100 years
  • Can take many years to mature6-25 years
    depending on species
  • SIZE
  • To 6.1 m (20 ft) and more than 1,134 kg (2,500
    lbs)
  • SWIMMING
  • Swim with their caudal fin (tail) and form an S
    shape with their body and tail

28
6.3 OCEAN LIFE
SCALES Five rows of large bony plates (scutes)
on body (1 on back, 1 at middle of each side
and 1 on each side of belly) Scutes better
developed in young, virtually disappear in old
individuals Skin between scute rows covered with
smaller bony scales TEETH Adults are
toothless DIET Barbels used to help detect
bottom-dwelling prey Slurp up prey with their
protrusible mouth Feed on bottom-dwelling
organisms worms, mollusks crustaceans BREEDIN
G REPRODUCTION All sturgeons spawn in
freshwater Sturgeon eggs/roe are highly valued as
caviar Several species are anadromous (spending
much of their life in the sea but moving to fresh
water to spawn) DISTRIBUTION Found in rivers,
lakes, bays and estuaries Northern hemisphere
North America, Europe, Russia (Caspian Sea, Black
Sea), Asia
29
6.3 OCEAN LIFE
CAVIAR Caviar refers to the processed, salted
eggs/roe of certain species of fish, most notably
the sturgeon. Sturgeon caviar or true caviar is
sold worldwide as a delicacy, and is usually
eaten by itself or spread on toast or blinis
(small, yeast-raised Russian buckwheat pancakes).
Sturgeon eggs are round and vary in size from
very small to pea-sized. Their colour can be
off-white, gold, light grey, charcoal grey, or
black. Most of the worlds caviar today comes
from sturgeons in the Caspian Sea, which is
ringed by Azerbaijan, Iran, Russia, Turkmenistan,
and Kazakhstan. The rarest and most expensive
are marketed as Beluga, Ossetra, and Sevruga
caviar, which come from the Great Sturgeon (Huso
huso), Russian Sturgeon (Acipenser
gueldenstaedtii) and Stellate Sturgeon (Acipenser
stellatus) respectively. Interestingly, the U.S.
also had a history in caviar production. For
most of the 19th century, the U.S. was the main
producer of the world's caviar. Caviar was
actually given away free with beer in saloons for
the same reason salty peanuts are given away
today. By 1910, however, lake sturgeons were so
over-fished they were nearly extinct and American
production was stopped. In 1925, the Caspian Sea
fisheries began the commercial production we know
today. Today, American caviar is mainly farmed
and typically comes from the White Sturgeon
(Acipenser transmontanus), Lake Sturgeon
(Acipenser fulvescens) and Shovelnose Sturgeon
(Scaphiryhnchus platoryhnchus). The market
demand and commercial value of caviar has
resulted in the serious decline in sturgeon
numbers worldwide, especially those from the
Caspian Sea. Sturgeons take many years to attain
maturity and the female sturgeon is killed in the
process of extracting the eggs. Thus, in spite
of some protection and alleviation of demand
through sturgeon farming, most sturgeon species
remain threatened or endangered.
30
6.3 OCEAN LIFE
CLASSIFICATION
31
6.3 OCEAN LIFE
STURGEON SPECIES 1. ATLANTIC STURGEONACIPENSER
OXYRHYNCHUS Long snout, sharply V-shaped and
upturned Viscera pale Labrador to Florida and
N.E. Gulf of Mexico Mostly in shallow waters of
continental shelf Enters larger rivers to
spawn Commercially important seriously
depleted To 3.1 m (10 ft) in length 2.
SHORTNOSE STURGEONACIPENSER BREVIROSTRUM Short
snout, not upturned at tip Short barbels Viscera
blackish New Brunswick to N.E. Florida Mostly in
river mouths, estuaries and bays but also enters
open sea Seriously depleted To 1 m (40 in) in
length
32
6.3 OCEAN LIFE
3. GREEN STURGEONACIPENSER MEDIROSTRIS 23-30
scutes in midside row 1-2 mid-dorsal scutes
behind dorsal fin 4 barbels nearer mouth than
snout tip Grayish white to olive-green Bottom
grubbing Often in brackish water Japan to
Northern Baja To 2.1 m (7 ft) in length and 159
kg (350 lbs) 4. WHITE STURGEONACIPENSER
TRANSMONTANUS 38-48 scutes in midside row No
mid-dorsal scute after the dorsal fin 4 barbels
closer to snout tip than mouth Grayish
white Spawns in spring in fresh water Important
commercially for flesh and eggs (caviar) Mainly
in fresh water occasionally moves to
ocean Common in large rivers Alaska to Northern
Baja To 3.1 m (10 ft) in length and 181 kg (400
lbs)
33
6.3 OCEAN LIFE
  • THREATS
  • Pollution and environmental degradation
  • Over-fishing for eggs/roe, meat and swim
    bladders
  • CONSERVATION
  • The World Conservation Union considers all but
    two of the worlds sturgeon and paddlefish
    species globally threatened. Consumer demand for
    caviar and the collapse of Russian law
    enforcement in certain areas have caused a boom
    in illegal poaching. Habitat destruction has
    also contributed to the decline of these fish.
  • IUCN classifies the Great/Beluga sturgeon (Huso
    huso) as Endangered. It is a protected species
    and its trade is restricted under CITES. The
    U.S. Fish Wildlife Service has also banned
    imports of beluga caviar and other beluga
    sturgeon products from the Caspian Sea since
    October 7, 2005.
  • The World Wildlife Fund suggests not buying
    Beluga, Ossetra or Sevruga caviar, or caviar from
    the Caspian Sea region, which includes Russia,
    Kazakhstan, Turkmenistan, Azerbaijan and Iran.
  • Sturgeon and/or paddlefish farming may become a
    viable means of sustainable commercial caviar
    production. It is currently practiced in Spain,
    France, Uruguay and the U.S. (California).
  • Dwindling sturgeon numbers has also resulted in
    the creation of caviar-quality roe alternatives
    from other fishes, such as Paddlefish, Whitefish,
    Cod, and Salmon.

34
6.3 OCEAN LIFE
REFERENCES FURTHER READING http//www.caviaremp
tor.org/ "Caviar Emptor" strives to protect
critically endangered beluga sturgeon and other
threatened Caspian Sea sturgeon species (source
of most of the world's caviar). http//www.fishba
se.org Excellent source of information about
fishes http//www.worldwildlife.org/trade/faqs_ca
viar.cfm World Wildlife Fund information on
caviar trade
35
6.3 OCEAN LIFE
  • 6.3.3 Sea Otters
  • DESCRIPTION
  • Long, sleek, furred, streamlined marine mammals
  • Largest member of the weasel family 1.2-1.5 m
    (4-5 ft) long and weigh 20-45 kg (45-100 lbs)
  • Webbed hind feet smaller front feet ears and
    nostrils close when underwater.
  • Dense, luxurious, dark-brown fur only marine
    mammal with almost no insulating fat
  • SPECIES
  • One species, Enhydra lutris, and two sub-species
  • Enhydra lutris nerisis Southern/Californian
    sea otter
  • Enhydra lutris lutris Northern/Alaskan sea
    otter
  • SIZE
  • Southern sea otters
  • Females 1.2 m (4 ft) in length 20 kg (45 lbs)
    in weight
  • Males 1.5 m (5 ft) in length 30 kg (65 lbs) in
    weight

36
6.3 OCEAN LIFE
FUR Two layers soft, warm, dense undercoat and
outer coat of guard hairs Densest fur of any
mammal 500,000-1,000,000 hairs per sq.
inch Groom fur with forepaws to keep the fur
waterproof Almost no layer of insulating fat Oil
spills cause the fur to lose its waterproofing
capability causing the sea otter to get
hypothermia and usually killing it POUCH Under
each foreleg and extending across the chest is
loose skin which can act as a pouch. Sea otter
may carry up to 25 sea urchins and a number of
clams or stones in this pouch depending on their
size.
37
6.3 OCEAN LIFE
38
6.3 OCEAN LIFE
SENSES Keen senses smell, hearing and sight Can
see very well, both above and below
water TEETH Powerful jaws for crushing Compact
molars with smooth cusps canines are rounded and
suited for crushing shellfish Look cute and
cuddly but they are large carnivores they can
and do bite! LIFESPAN Male 10-15 years in the
wild Female 15-20 years in the
wild GROOMING May spend 11-48 of daylight
hours grooming Extreme flexibility allows them to
groom all parts of their body DIVING Dive to
about 100 m (330 ft) Sea otters can hold their
breath for 5 minutes Most dives are about 1-1½
minutes long
39
6.3 OCEAN LIFE
DIET Carnivores (meat eaters) Eat crustaceans
(crabs, lobsters, shrimps), bi-valves (clams,
mussels, abalone), sea-urchins and snails Also
eat octopuses, squid, and fish Hunt for prey in
the ocean and on the sea floor Use rocks to help
crack open clams and abalone High metabolism
eat 20-30 of their body weight a day in the
wild. This would be equivalent to a 68 kg (150
lb) human eating 14-23 kg (30-50 lbs) of food a
day just to survive BEHAVIOUR Either solitary or
in groups called rafts Females avoid males
outside breeding periods Sea otters segregate
into male and female areas Diurnal hunt, feed
and groom during the day Sleep and rest on their
backs, usually anchored in kelp Wrap themselves
in mats of kelp to secure them from currents Tool
use underneath each front arm is a pouch of
skin used to temporarily store food and rocks
collected during extended dives to the bottom.
Floating on their backs, sea otters wash and
hammer or pry open prey with a favored rock they
keep in their pouch. Only mammal, besides
primates, known to use tools.
40
6.3 OCEAN LIFE
BREEDING REPRODUCTION Polygynous one male may
mate with several females Males reach sexual
maturity at 5-6 years old Females come into
estrus at 4-6 years old Births occur all year but
peak in Jan-Mar and Aug-Oct Females give birth to
one pup after a gestation period of 6-8
months Courtship is often very playful. Males
and females swim and dive together with the male
twisting and doing corkscrews in the water. The
male will also swim face down and much more
quickly than usual. Females may also have scars
on their nose from the males habit of holding
the females muzzles in their jaws during
copulation. May be a period of delayed
implantation during which the fertilized egg lies
dormant allows birth to be timed to when food
is more plentiful or conditions are
better. PREDATORS Generally only a
few Ocean Killer whales some sharks (great
white) birds (bald eagle) Land Bears and
coyotes
41
6.3 OCEAN LIFE
INTERESTING FACTS Bones can be pale violet from
eating purple sea urchins and absorbing a
chemical called polyhydronaphthoquinone from
the sea urchin. Fifth digit (pinkie) on the
hind foot is the longest digit, unlike that of
any other mammal. Uses a rock as an anvil and
hammers shellfish onto the rock to smash it open.
Rare example of mammalian tool use. Smallest
marine mammal Does not have blubber Has
little/no need to come onto land all life
functions can and are usually taken care of in
water (i.e. breeding, birthing, mating, eating,
resting, grooming, etc). Considered to be a
keystone species controlling the population of
several invertebrates, which would otherwise grow
unchecked.
42
6.3 OCEAN LIFE
CLASSIFICATION
43
6.3 OCEAN LIFE
HABITAT Shallow coastal waters of northern
Pacific Ocean. RANGE Live along rocky northern
Pacific Ocean coasts, bays and kelp beds.
Historic range throughout the northern Pacific
Ocean from Baja, California through Washington,
British Columbia, and Alaska to the Aleutian
Chain, Kamchatka, eastern Russia and northern
Japan. Much sparser distribution today due to
over-hunting of sea otters for their
pelts. POPULATION 2,500 southern sea otters off
the coast of California 27,500-52,500 northern
sea otters in Alaska, Canada and Washington.
15,000 in Russia
44
6.3 OCEAN LIFE
THE GREAT HUNT Between the 17th and 19th
centuries, Russia was heavily involved in the
sable fur trade. Peter the Great declared that
Russia should have the monopoly in sable furs and
that they should find new populations of sable to
hunt. The Russians conquered Kamchatka, at the
eastern edge of Russia, where they harvested
sable and sea otter fur, and explored the
northwestern Pacific looking for sea routes to
North America. Vitus Bering, a Dane in the
service of the Russian navy, was given the task
of mapping the Arctic coast from northern Russia
to the Americas. Berings 1741 expedition to
North America returned with 900 sea otter pelts
enough to pay for the entire expedition and set
what came to be known as the Great Hunt in
motion. Subsequently, the Russians sent many
ships to hunt sea otters, which depleted their
populations in the Commander and Aleutian
Islands. By 1776, the Americans and Europeans
were also hunting sea otters and competing with
one another for domination of the fur trade. By
1867, Alaska was almost completely depleted of
sea otters. It wasn't until 1911 that an
international treaty was signed to stop the
hunting of sea otters and the Great Hunt was
finally over. By that time, however, so few sea
otters remained, many assumed they would become
extinct. Indeed, all California sea otters were
thought to be extinct into the 1900s. In 1915,
however, 32 sea otters were discovered at Point
Sur in California. So fragile was this remnant
population that biologists kept it secret from
the public until the 1930's. This and other
surviving groups would form the nucleus for the
restoration of the sea otters. Since then, and
under strict protection, both Northern and
Southern sea otter populations have grown
considerably but in some areas, their numbers are
still precariously low (hence the Southern sea
otters Threatened status). Today, new
challenges threaten the sea otters existence,
including pollution and habitat destruction.
45
6.3 OCEAN LIFE
THREATS Hunting almost driven extinct in the
past protected today Oil spills pollution
Habitat loss Disease and medical problems
Gill net entanglement Human-sea otter
competition sea otters can damage valuable
abalone shellfish farms CONSERVATION California
(Southern) sea otters listed as threatened
under the federal Endangered Species Act (ESA)
and are fully protected under California state
law. Alaskan (Northern) sea otters are
endangered. All otters in the USA are
protected under the US Marine Mammal Protection
Act (MMPA). Canadian otters are classed as
threatened by the Committee on the Status of
Endangered Wildlife in Canada (COSEWIC). Even
though they are protected, some threats have no
boundaries Exxon Valdez spill in Prince
William Sound, Alaska (1989) killed several
thousand sea otters Sticky crude oil causes
water-logging of the coat the animal quickly
chills in the cold water May also succumb to
the toxic components in the oil
itself REFERENCES FURTHER READING http//www.ma
rinemammalcenter.org/learning/education/teacher_re
sources/cleanseaotter.asp http//en.wikipedia.org/
wiki/sea_otter - sea otter species information,
habitat, behavior, threats
46
6.4 ACTIVITIES
6.4 ACTIVITIES
47
6.4 ACTIVITIES
6.4 ACTIVITIES 6.4.1 Horseshoe Crabs CORE
ACTIVITY (a) Colour the horseshoe crab olive
and add the following labels to your picture
Top View Head (prosoma) Eyes Eyes (second set) Flange Hinge Abdomen (opisthosoma) Spines Tail (telson) Bottom View Mouth Flange Feeding pincers (chelicerae) Tail (telson) Walking legs Book Gills Anus
48
6.4 ACTIVITIES
49
6.4 ACTIVITIES
(b) What are some differences between a horseshoe
crab and true crab?
Horseshoe Crabs True Crabs

(c) What colour is horseshoe crab blood? (d) If
you have to pick up a horseshoe crab, where
should you hold it?
50
6.4 ACTIVITIES
ANSWERS (a) Colour the horseshoe crab olive and
add the following labels to your picture
Top View Head (prosoma) Eyes Eyes (second set) Flange Hinge Abdomen (opisthosoma) Spines Tail (telson) Bottom View Mouth Flange Feeding pincers (chelicerae) Tail (telson) Walking legs Book Gills Anus
51
6.4 ACTIVITIES
52
6.4 ACTIVITIES
(b) What are some differences between a horseshoe
crab and true crab?
Horseshoe Crabs True Crabs
No antennae No mandibles Multiple un-stalked eyes Molt by walking forward out of their shell Have antennae 1 pair of mandibles Stalked eyes True crabs back out of their shell when molting
12 legs (6 pairs) including 6 pairs of claws 1st pair (chelicerae) for feeding 2nd pair (pedipalps) differentiate gender Remaining pairs are walking legs 10 legs (5 pairs) including 1 pair of claws
(c) What colour is horseshoe crab
blood? Light-blue, copper-based blood (unlike
humans, which have red, iron-based blood) (d) If
you have to pick up a horseshoe crab, where
should you hold it? From the flange at the front
of the head as though you were holding a bicycle
helmet not by the tail as you can snap it off!
53
6.4 ACTIVITIES
  • 6.4.2 Sturgeons
  • CORE ACTIVITY
  • (a) Colour the sturgeon dark grey and add the
    following labels to your picture
  • Scutes (plated scales)
  • Pectoral Fin
  • Caudal Fin (tail)
  • Barbels (whiskers)
  • Snout
  • Eye

(b) What is caviar? (c) Why are sturgeons
endangered? (d) Why is the gathering of caviar
from sturgeons so detrimental to the population?
54
6.4 ACTIVITIES
  • ANSWERS
  • (a) Colour the sturgeon dark grey and add the
    following labels to your picture
  • Scutes (plated scales)
  • Pectoral Fin
  • Caudal Fin (tail)
  • Barbels (whiskers)
  • Snout
  • Eye

55
6.4 ACTIVITIES
(b) What is caviar? Caviar refers to the
processed, salted eggs/roe of certain species of
fish, most notably the sturgeon. Sturgeon caviar
or true caviar is sold worldwide as a delicacy,
and is usually eaten by itself or spread on toast
or blinis (small, yeast-raised Russian buckwheat
pancakes). Sturgeon eggs are round and vary in
size from very small to pea-sized. Their colour
can be off-white, gold, light grey, charcoal
grey, or black. (c) Why are sturgeons
endangered? Pollution and environmental
degradation Over-fishing for eggs/roe, meat
and swim bladders (d) Why is the gathering of
caviar from sturgeons so detrimental to the
population? There are at least three
reasons 1. Gathering caviar (eggs) removes the
next generation of sturgeons. 2. The female
sturgeon is killed in the process of extracting
the eggs. 3. Sturgeons take many years to reach
maturity and reproductive age
56
6.4 ACTIVITIES
  • 6.4.3 Sea Otters
  • CORE ACTIVITY
  • Colour the Sea Otter dark brown and add the
    following labels to your picture
  • Eye
  • Forepaw
  • Skin/Fur
  • Nostril
  • Hindpaw
  • Ear
  • Tail

(b) Name some of the sea otters most unusual
features
57
6.4 ACTIVITIES
58
6.4 ACTIVITIES
(c) Sea otters are found along the coast of the
North Pacific ocean. Label the map with the
following places California (CA), USA
Alaska (AK), USA Canada Kamchatka Peninsula
Russia China
59
6.4 ACTIVITIES
  • ANSWERS
  • Colour the Sea Otter dark brown and add the
    following labels to your picture
  • Eye
  • Forepaw
  • Skin/Fur
  • Nostril
  • Hindpaw
  • Ear
  • Tail

(b) Name some of the sea otters most unusual
features Bones can be pale violet from eating
purple sea urchins Fifth digit (pinkie) on
the hind foot is the longest digit, unlike that
of any other mammal. Uses rocks as an anvil and
hammers shellfish onto the rock to smash it
open Smallest marine mammal Does not have
blubber Densest fur of any mammal
500,000-1,000,000 hairs per sq. inch
60
6.4 ACTIVITIES
61
6.4 ACTIVITIES
(c) Sea otters are found along the coast of the
North Pacific ocean. Label the map with the
following places California (CA), USA
Alaska (AK), USA Canada Kamchatka Peninsula
Russia China
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