Agnatha- Should
be done around 9 or 10 tonight
Pacific Hagfish
Eptatretus stouti
Jean McCrae
Oregon Dept. of Fish and Wildlife
Ecology The Pacific hagfish ranges from Southern California to Southeastern
Alaska in depths of 10-500 fm. They are most abundant in shallower depths,
40-100 fm. Hagfish are found mostly over muddy bottoms, but occasionally on
rock bottoms.
Life History Reproduction Sexes are separate, however, hermaph-roditic adults
are occasionally found. The sex of an individual fish is not easily
distinguishable for fish under 35 cm in total length. Some consider the
juveniles to have a temporary form of "juvenile progynous hermaphroditism"
and environmental factors may have an influence on sex differentiation. No
distinct spawning season has been documented as females and males can be found
in various stages of sexual maturation year-round. However, there is a
suggestion of a spring and early summer spawning season as more females with
large eggs can be found during that time. There has been no documentation as to
exactly how hagfish reproduce. The average number of eggs laid at one time is
approximately 20-30. Eggs are probably laid once a year, but possibly at longer
intervals. Mature females often contain more than one distinct size group of
eggs. The less developed eggs do not develop further until the largest-sized
batch has completely matured and been released. Strings of eggs have been found
in 15-25 fm depths. When eggs hatch, the young emerge as small hagfish, not as
larvae. There apparently is a high survival rate of young hagfish. Food and
Growth Hagfish have no known natural predators, although egg and adult black
hagfish have been found in the stomachs of sablefish. Hagfish, themselves, feed
on dead and dying fish, burrowing into the prey and eating the flesh and
viscera, leaving a bag of skin and bones. Males have been known to eat hagfish
eggs. Hagfish rely on well developed nasal organs to find their food. They
probably can go for a long time without food. The smallest free-swimming
hagfish was 60 mm, while the largest embryo still in its capsule, but ready to
hatch, measured 65 mm. Adult hagfish range in length from 12-25 inches. The
largest specimen noted was a male of 32.3 inches. In general, females are
larger than the males. Migration There is some indication (unconfirmed) Pacific
hagfish migrate from shallow waters in the late summer. Seasonal migrations
have been documented for other species of hagfish.
Population High ratios of female to male hagfish can often be found. It is
uncertain whether the difference is real or reflects a difference in behaviors
between the sexes. No estimates of abundance or biomass have been made for
Pacific hagfish. There has been no documentation of separate stocks, but there
are suggestions of isolated local populations in other species. Aging of
Pacific hagfish has not been done due to lack of hard body parts in the fish
that would bear annual marks
Chondricthyes-
General Information: The Great White Shark has been the feature in such movies
as Jaws , Jaws 2 , Jaws Revenge , Shark Attack & Shark Attack 2. It is the
most popular and deadliest shark in the ocean.
Size: The Great White Shark is the biggest of all the deadliest sharks, There
have been reports of Great Whites exceeding 20 feet in length and wieghing in
at over 7000 lbs. Normally a fully grown mature Great White will be in the 13ft
to 17ft range and weigh around 2 - 4000lbs. Females are also larger then males.
Teeth: Mature Great Whites have teeth in the 1 1/2" to 2" range
usually, but there are known modern teeth that are over 2 1/2" long. Even
though most places report Great whites as having max. 3 inch teeth , there are
no modern teeth close to that size. However there are fossil teeth of great
whites that not only meet 3" but exceed it. Our Last report shows the
biggest Great White fossil tooth found was over 3 1/2"!
Color: The Great White Shark is only truly white on its belly, its top is
actually a grey or blue/gray in color, which makes it hard to spot in the
water.
Feeding Habits: The primary diet for Great Whites are sea lions and seals, but
they will also eat Sea Turtles , Otters , smaller whales or if they can find
any they will also eat dead fish , whales or animals in the water. Younger
Great Whites eat fish , rays and smaller sharks. Great White Sharks do not chew
there food , they take big massive bites and swallow the peices whole. Most
attacks on humans from Great Whites are mainly because it thinks you are one of
its primary meals , but after one bite it will usually back off as it notices
its not. However the biggest blow the sharks give is in there initial attack,
as its used to disable the creature for easy eating. This is why if you get
attacked by a great white the chances are 50/50 for survival. Mainly due to
blood loss will be the reason most people die.
Senses: The Great White Shark primarily use their sense of smell and sense of
electic charges. Their other senses like eyesight and hearing are less
important. Their nostrils can smell one drop of blood in 100 liters of water (
25 gallons ). The sharks nostrils are only used for smelling and not for
breathing like humans.Sharks breath through their gills.
Social Behavior: Great White Sharks are solitary animals but on occasion have
been spotted travelling in pairs.
Habitat | Migration | Distribution: Great White Sharks are found near shore
around most of the temperate coastlines around the world. They dont like the
water hot nor cold , they like it warm. Great Whites have been found along the
coastlines of California all the way to Alaska , the east coast of the United
States and most of the Gulf Coast, Hawaii , South America , South Africa ,
Austrailia ( except the north coast ) , Japan , Mediterranean Sea , New Zealand
, West Africa to Scandinavia , Eastern Coastline of China and Southern Russia.
In the fall some female Great White Sharks migrate to warmer waters to give
birth.
Life Span: No one accurately knows the life span of the Great White Shark
although some believe it to be around 100 years.
Reproduction: Great White Sharks reproduce " Aplacental Viviparity "
which means the sharks hatch from eggs but the eggs are still inside the female
shark's body. There is no Placenta to nourish the pups so they must eat the
unfertilized eggs or eat their siblings to stay alive. So even before there
born they must kill and fend for themselves or they will be eatin. Once the
mother gives birth , the baby great white sharks swim immediately away and no
maternal care is givin. Females give birth to 7 - 9 live pups per litter and
are thought to only produce 4 - 6 litters in an entire lifetime. The young
Great White sharks do not mature until they reach the age of about 10 - 12
years old , therfor Great Whites are extremely Vulnerable to overfishing.
Swimming: Great White sharks use there big powerful tails to propel them in the
water. The fins are only used for balance. They average about 2 mph but can
burst to 15 mph when trying to catch prey. Great White sharks must swim
constantly or they would since to the bottom of the ocean. Like other sharks ,
they have no gas filled bladder to keep them afloat like bony fish do. Also
like other sharks they have a large , oily liver that provides some floating
ability. Great Whites cannot swim backwards or even come to an abrupt stop ,
because their fins are not flexible like other fish. Great Whites also must
keep moving to breath , this is why if they get caught in nets the die very
fast. Great Whites are also only one of a couple species of sharks that jump
out of the water while catching prey. They sometimes go down deep in the water
and rocket skyward to catch their prey.
Population Report: Great White sharks are NOT an endangered species , but they
are decreasing in big numbers and may eventually become on this list. This is
Why the Great White is now protected almost Globally including places like USA
, Australia and South Africa. It is also Illegal to import or export Great
White shark teeth and jaws.
Osteicthyes-
Inshore Lizardfish
Synodus foetens
Description To 16" (41 cm).
Elongate, cylindrical; brownish or olive with greenish cast above, whitish or
yellowish below; sides with obscure blotches, fading in large specimens. Snout
pointed, head depressed, with light, wavy lines. Eyes large, above midpoint of
maxilla. Pectoral fins dusky, yellowish, or light green; adipose fin with dark
spot. 60 lateral line scales.
Habitat Bottom-dwellers, usually
near shore or to about 15 fathoms. The Synodontidae or Lizardfish Family
has 40 species, of which 31 are of the genus Synodus. Five of these reside in
the eastern Tropical Pacific and all five are found in Mexican waters. The
lizardfishes have slender cylindrical bodies, pointed "lizard-like"
heads with large mouths that have many rows of fine teeth. They have one dorsal
fin, mid-body, and a small adipose fin along the back, large pelvic fins with
eight or nine rays that are located on the abdomen behind the pectoral fin, and
a forked caudal fin. The fins are without spines and they have a straight
lateral line. Lizardfishes are sedimentary bottom dwellers found sitting
motionless, perched on their pectoral fins, or buried in the sand with one eye
exposed, waiting to ambush unsuspecting prey. They are voracious predators
feeding primarily on small fishes, krill, squid, and shrimp.
Range From Massachusetts to
Brazil, including Bermuda, Gulf of Mexico, and West Indies. Uncommon north of
South Carolina.
Discussion This is a very common
lizardfish in the northeastern Gulf of Mexico, where it is often caught in
shrimp trawls and discarded as a trash fish.
Bibilography:
Great
White Information