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Exploring the beautiful nature of California
Marine Fish: California Sheephead
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Fishes are aquatic vertebrates that have fins, gills and
scales. Gills are the part of the respiratory system that
provide surface area for exchanging oxygen and carbon dioxide
under water.
Fish are ectotherms, commonly referred to as
'cold-blooded', meaning their temperature is regulated by the
temperature of their environment. They have a range of diets,
being herbivores, carnivores, or omnivores. Some fish reproduce
by laying eggs, while others reproduce by bearing live young.
California fish species reside in freshwater and coastal/marine
waters. Coastal, or marine fish are an abundant and valuable
resource. However, the ocean's supply is not limitless, and
therefore careful planning and education must be undertaken to
ensure the sustainability of the world's largest food source.
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All California sheepheads are female until they are seven or
eight years old when they morph into males, which they remain
for the rest of their fifty year life span.
In 1990,
Robert Cowen studied sheephead in four sites where the
availability of food varied. In the area with the most food,
females changed sex at about 13 years old and lived about 21
years. In the area with the least food, females changed sex at
five to six years old and lived about nine years. At least in
these two areas, the females changed sex about two-thirds of the
way through their life spans.
Male and female sheephead have different
color patterns and body shapes. Males are larger, with black
tail and head sections, wide, reddish orange midriffs, red eyes
and fleshy forehead bumps. Female sheephead are dull pink with
white undersides. Both sexes sport white chins and large,
protruding canine teeth that can pry hard-shelled animals from
rocks. After powerful jaws and sharp teeth crush the prey,
modified throat bones (a throat plate) grind the shells into
small pieces.
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During mating season (between July and
September) male sheephead become territorial and defend their
spawning territory. Dominant males lead the females in a
circular pattern as they broadcast sperm and eggs, respectively.
If a smaller male approaches, the male interrupts spawning
activity to chase away the intruder.
The females spawn between 36,000 and 296,000 eggs, which hatch
into larvae. The young of the year sheephead don’t resemble
adults; they’re a bright reddish orange with large black spots
on their dorsal and upper tail fins and a white stripe running
the length of their bodies.
Historically, California sheephead up to 36 pounds and three feet in length were landed, but fewer large fish are found today. Catch limits for sport, dive and commercial landings are set annually with minimum size limits and seasonal restrictions to protect spawners.
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Sheephead hunt
actively during the day, but at night, as many wrasses do, they
move to crevices and caves and wrap themselves in a mucus
cocoon. Predators on the hunt can’t detect the fishes’ scent
through the mucus covers. Sheephead appear to be asleep, but
since fishes don’t have eyelids, we can only assume they’re
sleeping.
They range from Monterey Bay to the Gulf of California in the Pacific, feeding chiefly on the bottom on mollusks, urchins, crabs, and lobsters. California sheephead are prey to seals, sea lions, and giant sea bass.
California sheephead are popular with anglers and spear fishers,
but the annual catch in California is no more than about 50,000
fish. During the late 1800s, Chinese fishermen caught large numbers of sheephead for drying and salting. Except for brief periods, fishermen didn’t target sheephead again until the late 1980s, when commercial fisheries began to supply live fish to Asian markets and restaurants. |
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