Crayfish

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Crayfish Reproduction (important)

1.     Mating and reproduction are easily accomplished under intensive culture conditions

2.     Mating and egg fertilization are asynchronous (non-gravid vs. gravid)

3.     Egg-laying typically occurs in burrows

4.     Eggs (~300/female) are attached to the swimming legs of the female by glair (viscous material of egg white)

5.     Eggs hatch in about 3 weeks at water temperatures of 20 degrees C.

Decapods

1.     Ten paired legs

2.     Abdomen (tail) Carapace (body) – 5 pair of legs on each the abdomen and carapace.

3.     Legs on abdomen are swimming legs

4.     Legs on carapace are walking legs

Crayfish ponds

-Crawfish are cultured in shallow open ponds. Pond areas vary from 2 to 16 ha (LA, TX)

-Pond depth is generally 30-60 cm bud deeper ponds are required in areas that have hotter summers

-Ponds have to be located near a source of good quality surface or well

-Water hardness = ~100+ or – 40 calcium

-DO (dissolved oxygen) > 3 ppm

-Grow-out = >10 cm in total length (20-50 grams) in 3-6 months

Crayfish are omnivores – they eat everything basically

Double cropping (crayfish / Rice – Polyculture)

Rice – crawfish – rice rotation

Management Actions

March/April – Plant rice ~4 months to harvest

June – At permanent food, rice grows to 20-25 cm high // stock 50-60 kg of adult crawfish/ha in new ponds

August – drain pond over 1 week period and harvest rice

October – re-flood pond

November-March – Harvest crawfish

March/April – Replant rice. No restocking of crawfish necessary.

Single crow crawfish pond (monoculture)

-Two additional months of crawfish harvest

April/May – stock 50-60 kg of adult crawfish/ha in new ponds

May/June – Drain pond over 3-4-week period

June/August – Plant forage crop October – Re-flood pond

November to May – Harvest crawfish

May/June – Drain pond over 3-4-week period. No restocking of crawfish is necessary.

Advantages of Polyculture – Additional crop (rice) / Environmentally friendly

Advantages of monoculture – Ponds flooded during hot summer months / 2 harvests of crawfish

Disease, pest and predator control

1.     Primary loss of crawfish from Louisiana ponds is to bird predators, such as herons and egrets

2.     North American species carriers of a fungal disease, the “crawfish plague”. While not problematic for North American species it is deadly to many other crayfish species in the world

3.     Introduction of Louisiana crayfish into Africa and Europe have devastated native species susceptible to the “crawfish plague”

Two species dominate crayfish harvest in the US

1.     Red swamp crawfish 85%

2.     White river crawfish 15%

Trap Harvest (both fishery and aquaculture)

-       Three-funnel pyramid trap made from ¾ inch mesh PVC-coated wire

-       The ~2.0 cm mesh size commonly used to construct the traps allow escape of crawfish less than ~8cm in length (considered the minimum marketable size)

Crawfish Production

1.     40% USA

2.     40% China

3.     20% Spain

Crayfish traps

1.     Density = 25 – 50 traps/hectar

2.     Baited (1/3 lb fish or manufuactured bait) and harvest

Crawfish distribution

1.     Sacked for distribution in “onion” sacks with ¼ mesh; 35 lbs/sack (must turn onion sack over once in a while to relief pressure off bottom crawfish)

2.     Storage at 4-7 C for 5 days without excessive mortality (Q10 effect, low temperature means lower metabolism)

3.     Turned once a day, stacked no more than 3 sacks high

Oysters - Yummy in my Tummy!

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Oysters

Of all the oysters produced 4,400,000 mt (98%) are a single species – the Japanese oyster (crassostrea gigas)

WHY?

1.     Fast growth

2.     Highly adaptable

3.     Demand -> taste/size

A little bit of “Oyster history”

-       Olympia oysters is the native spcies

-       S.F. oyster beds depleted by 1851 as a result of overharvesting

-       After that east coast oysters arrived by ship in barrels and cost 6$ a piece

With the opening of the transcontinental Railroad in 1875 “relaying” of Eastern oyster seed for growout in S.F> bay was started

-       1889 1.5 mt of seed imported

-       1899 1,100 mt of oyster meat produced

-       1908 down to ~ 600 mt of oyster meat

-       1919 Eastern oyster stocks suffered a massive mortaility

-       1921 Seed shipments discontinued

-       1939 Holding of imported stock halted

Japanese or Pacific oysters

-       Tougher and more suitable for aquaculture than the Eastern Oyster

-       Grows in brackish water upwards of > 16 ppt salinity

-       Grows at temperatures between 10-30 C

-       Withstand <0C

-       Withstands period of turbid water conditions

Problem – requires temperature greater than 20C for spawning

Oyster Life cycle

Fertilized Egg > Trochophora Larvae > Veliger larva > Spat (few mm size) (all done in hatercy up to this point) > Adult stage

Cultch

-Cultch is used in shellfish aquaculture as a substrate on which oyster spat can grow.

- The clean shell (cultch) is used in the hatchery to receive larval settlement

- Oyster seed is shipped to grow-out areas a spat on cultch

- After 1-4 years the settled oysters are removed and the empty shells recycled as cultch

Development of Oyster Hatcheries on the U.S. West Coast – 1980’s

Drivers

1.     Cost of Japanese spat was rising

2.     Infrequent natural spawning of C. gigas because of low water temperature

Broodstock used in oyster hatcheries

-Broodstock is conditioned for 2-6 weeks in flow-through trays while being fed algae

- generally, 30% males (1.5 – 2 years old) and 70% females (2.5 years and older) are used as broodstock

- Each female will produce millions (60-90 million) eggs

Induction of oyster spawning

-       Temperature shock

-       Spawning = excretion of gametes (unfertilized eggs and sperm) into the water

-       Blender technique to maximize fertilization

Oyster Harvest

Oyster cultured in bags, trays and on ropes are often harvested mechanically because of their heavy weight

Grow-out in California takes 13-18 month to produce a 4-inch oyster.

Shellfish Food safety regulation

National Shellfish Sanitation Program (NSSP) under supervision of the FDA

-Requires that both farmed and wild harvest-growing areas be distinctly demarcated

- Requires that each growing area is regularly tested for pathogens and classified as to water quality as determined by fecal coliform (gut bacteria0 counts

Food Safety Problems

1.     Deadly bacteria – can infest oysters and causes lethal septicemia in individual with impaired immune system

2.     Toxic algae (Cooking does not destroy these algal toxins)

Sponges - the most dominate species in the ocean?

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Sponges

Most primitive metazoan – Multicellular animals

Symbiosis – mutually beneficial relationships with many other organisms

Over 10,000 species

Sedentary/sessile (immobile)

Few mm to over m in size

Grow slow and can get very old

A sponge farmer must have a basic understanding of sponge biology, their life cycle, what they eat, and how they reproduce to grow a healthy and bountiful sponge crop.

Five main cell types

1.     Choanocytes = collar ells with cilia that whip back and forth

2.     Porocytes – Cells with holes (ostia or pores

3.     Sclerocytes = Cells that form spicules

4.     Amoebocytes = cells that can move and differentiate

5.     Spongocytes = cells that form sponging and collagen (Connective tissue)

Spicules are made from either CaCO3 or SO2

Sponges feeding strategy

Filter feeders (plankton, bacteria)

In general, the more food particles in the water surrounding a ponge, the faster it will grow.

Oxygen, nutrients uptake is facilitated by choanocytes and porocytes

Waste excretion (CO2, ammonia)

Amoeboid cells facilitate waste removal and oxygen distribution

Sponge Reproduction

Sexual reproduction: Most sponges are hermaphrodites (Produce both sperms and eggs, self fertizaition)

Gemmulae: Some sponges release small packets of cells that settle to the bottom and create a new sponge

Budding: Some sponges reproduce by forming buds that separate

Regeneration: When a sponge is damaged or cut into small pieces, as may happen in a storm, each piece can grow into a new sponge. (It is this ability to reproduce from small cuttings that makes commercial sponge farming feasible)

Commercial sponge farms

Most of the activity in sponge aquaculture is occurring in the Federated States of Micronesia and other US-Affiliated Pacific countries

In the late 1930s and early 1940’s, Japanese farmers in Micronesia experimented with different sponge growing techniques but their efforts were halted by the outbreak of World War II

Leading expert in sponge aquaculture: Richard Croft, sponge farmer and researcher living in Pohnpei, Federated States of Micronesia

Location of a Sponge farm

The aquaculture species should be native to the area

Keep the sponges away from fresh water

The water should be at least five feet deep at low tide to avoid overheating and UV damage but should be manageable

Cost of sponge aquaculture

Low cost – Material cost <1000$ USD

Three benefits of sponge aquaculture

1.     It’s easy – very little special knowledge required

2.     It’s profitable – Source of continuous income year round….Two sponge farmers working three half days per week can expect to plant 30,000 sponge cutting in a year and earn approx. 10,000 to 12,000$

3.     It’s environmentally friendly – No harm to marine ecosystems if done well…..Reduction of harvesting pressures on local wild sponge stocks……Automatic restocking as a side effect (Site has to be chosen carefully)

Sponge growth rate

-Generally, most species of sponges grow slowly

-Growth is species-depedent

-Sponge growth is temperature-dependent

Artificial selection can be done to enhance growth rates

Q10 effect – with every 10C increase in environment temperature, there is doubling in growth.

Commercial markets and applications

Natural sponges are currently in considerable demand worldwide for their numerous medical, industrial, cosmetic and household uses, including:

1.     Hospital purchase natural sponges because of their unique ability to withstand high sterilization temperatures

2.     Use for bathing and cosmetic purposes

3.     Use for window washing

4.     Use for the application of industrial lubricants

5.     Use as gifts and art products

Sponge broodstock

-Broodstock = supply of parent sponges

-Parent sponge is cut into pieces and each cutting will grow into a new, full sized sponge

Broodstock can be obtained from:

a)    Wild stocks

b)   Donated by government nurseries

c)    Purchased from other sponge farmers

Sponge grow-out methods

Selection of grow-out method is usually based on:

a)    The cost of the materials

b)   The ease with which a farmer can work on the sponges

c)    The adaptability of the technique to different reef conditions

Grow out methods:

1.     Attachment of sponges to concrete discs along the bottom of the ocean

2.     Hanging of sponges on vertical lines extending from bamboo rafts

3.     Hanging of sponges along lines attached to beer bottle floats

4.     Horizontal line method (Currently the most widely used and economical)

Food's Forklore

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 3. Forklore: Never eat pork away from home

            - Undercooked pork can contain a parasite called trichinosis (also found in pork, bear, rat, fox, dog, wolf, horse, seal, or walrus)

4. Forklore: Honey in baby formula is a safe natural sweetener

            -Botulinum spres are found in honey

            -Adults who eat these spores are almost never affected

            -Infants eat spores the spores can germinate in their immature gastrointestinal tracts (SIDS)

5. Forklore: Only certain people cry when cutting onions

            -only people with eyes will cry so everyone

            - sulfur are absorbed by the onion in the soil

            -Sulfenic acid are released when the onions cells are broken (Lachrymators)

            - Lachrymators combine with water to form sulfuric acid

            - The eye produce tears to wash the acid out of your eye.

6.  Forklore: Refine sugar is empty calories and poisons the body

            - Carbohydrates causes obesity and insulin resistance in the United States

            -It’s empty calories, and may influence insulin resistance however it is certainly NOT poisonous. (At normal doses)

7. Forklore: You can get high on nutmeg

            -Yes, nutmeg contains a hallucinogenic compound called myristicin

8. Garlin will protect you from disease

            -Garlic was worshipped by the ancient Egyptians, chewed by greek Olympian athletes and thought to be essential for keeping Vampires (mosquitos) at bay.

            -Scientists have identified a potent antimicrobial ingredient in garlic call Allicin

            -Allicin is also protective in cardiovascular disease

9: Forklore: Brown eggs are more nutritious than white eggs

            -No, white leghorn chickens lay whites eggs

            -Brown eggs are breeds such as barred Rock and Rhode Island Red

10: Eating raw oysters has strong aphrodisiac effects

            -Oysters contain 2 unusual amino acids, D-aspartic acid (D-ASP) and N-methyl-D-aspartate (NMDA). These amino acids can cause increased production of testerone. (Ans: maybe)

11: Forklore: Irradiate foods contain residual radioactivity

            -No

            -Ionizing radiation kills bacteria and parasites that would otherwise cause foodborne disease but it passes though the food

12 Forklore: Brown rice is more nutritious than white polished rice

            -Yes

            -Brown rice contains the bran and germ layers, which are rich in nutrients

            -White rice is milled and polished so these layers and nutrients are removed

13: ForkLore: Kosher salt has been blessed by a rabbi

            -Nonsense

14 Forklore: Pasteurizing milk destroys all the vitamins, calcium, phosphorous and enzymes

            -Nonsense

           

15 Forklore: Green potatoes can be poisonous

            -When potatoes are exposed to sunlight they produce poisonous compounds called alka loids

            -Store potatoes in the dark, and cut away green areas

16: Forklore: Cooking meat on a BBQ causes the formation of carcinogens

            -YES

            -no clear evidence BBQ meats cause cancer

17 Forklore: Chocolate is a health food

            -No

            -Chocolate does contain antioxidant but unclear on its effect

18 Forklore: drinking gin prevents malaria

            -NO

19 Forklore: Drinking red wine prevents heart attack

            -Don’t know for sure

The beginning

I’ve created this blog website specifically for the purpose of my online class at Fresno City College titled “COMM 15″. This class is all about modern day communications on the web. At the time of this post, we have already completed a collaboration project which taught us how to communicate effectively with other peers solely with the use of online communication. Not only that, but we also collaborated to build a website that informs people of great recipes. I would like to say what a great class this is and the professor does a very good job of organization and convey the materials online. Although online classes can be challenging, I strongly urge those whom have a busy life style to consider online education.