dungeness-crab warning

dungeness-crab Energy plan
REEDSPORT How to Identify DungenessCrabs Dungeness crabs are located
on the Pacific west coast of North America and are found as far north
as Alaska or as far south as Mexico. When you go crabbing forDungeness
crabs, it is important toknow how to recognize the crab you are
looking for, if the crab is ajuvenile or an adult, as well as the
difference between a male and a female Dungeness crab.
Difficulty:
Moderately Easy
Instructions
1.
Locate the claws on the end of the Dungeness crab legs; Dungeness crab
claws have whitetips at the end. Count the numberof legs on the crab.
It should have five legs on each side.
2.
Examine the shell of the crab to see the color. Dungeness crabs range
from a reddish-brown to dark purple in color.
3.
Measure the size of the Dungeness crab to determine if you have a
juvenile or an adult crab. An adult crab measures around 7-inches
wide. Examine the color of the shell. If the shell has a greenish hue,
it is a juvenileand must be returned to the water.
4.
Flip the Dungeness crab over on its back so that its underside of the
shell is exposed. Examine the crab. Females have a wide underside of
the shell area shaped like a lemon while males have a narrow underside
of the shell area. Release any female crabs you catch so that they can
reproduce; the Oregon Dungeness Crab association states that this is
the law.
Tips & Warnings
*. Purchase a fishing license before you fish for Dungeness crabs. If
a state Fish and Game warden finds that you are crabbing without a
license, you will be fined.
*. Keep your fingers clear of the claws on the Dungeness crab because
the claws can pinch.
References
*. Oregon Dungeness Crab Commission: Dungeness Biology
*. Oregon Dungeness Crab Commission: Identifying Crab
*. Oregon Department of Fish and Wildlife; Recreational Crab Fishing;
Crab Identification
reddish-brown to dark purple in color.
dungeness-crab warning
Marquis reagent
The Marquis reagent test in color of shell fish ie: crab family - test
is not safe for enviroment
The Marquis reagent is used as a simple spot-test to
presumptivelyidentify alkaloids as well as other compounds. It is
composed of a mixture of formaldehyde and concentrated sulfuric acid ,
which is dripped onto the substance being tested. The United States
Department of Justice method forproducing the reagent is the addition
of 100 mL of concentrated (95–98%) sulfuric acid to 5 mL of 40%
formaldehyde. [ 1 ] :12 Different compounds produce different color
reactions. Also, sometimes methanol is added to slow down the reaction
process to observe the change in color better. Methanol does this by
slowing down the polymerisation process.
It is the primary presumptive test used in Ecstasy testing kits . It
can also be used to test for such substances as opiates (e.g. codeine
, heroin ), and phenethylamines (e.g. methamphetamine , amphetamine ).
The test is performed by scrapingoff a small amount of the substance
and adding a drop of the reagent (which is initially clear and
colorless). The results are analyzed by viewing the color of the
resulting mixture, and by the time taken for the change in colorto
become apparent:
Each year in the United States millions of illnesses and thousandsof
deaths are traced to contaminated food, with an estimated cost from
US$5 billion to over US$22 billion. Experts believe that the risk of
food-borne diseases has increased during the last 20 years (United
States General Accounting Office, 1996a). Food-borne diseases can
originatefrom consumption of viruses or bacterial pathogens, toxic
substances and parasites. It has been estimated that about half of all
food-borne disease outbreaks remain unrecognized, primarily dueto
inadequate diagnostic methods and sampling (Svensson, 2000).
2.1 Toxins
Fish are implicated in 25 percent offood-borne disease outbreaks in
the United States; 86 percent of them due to biotoxins, mostly
ciguatera (Olsen et al ., 2000; Valdimarsson, Cormier and Ababouch,
2003). The effect of these biotoxins, their chemical structures and
methods of detection have been the subject ofseveral reviews (Botana
et al., 2002;Daranas, Norte and Fernández , 2001; Lehane and Lewis,
2000; Todd, 1993; WHO, 1984) and the reader should refer to those
publications for detailed information. Table 1 gives some data on the
most common toxins.
The classical method to detect toxins is the mouse bioassay: miceare
injected with an extract of a suspect sample and their mortality is
registered. The method is expensive, not-specific, highly variable,
with low sensitivity, only a limited number of samples can be
processed, it is slow, it requires specialized facilities and it
involves the use of live animals. For all these reasons it is highly
desirable to find a more humane, easier andcheaper method. The newer
detection procedures focus on: i) detecting the toxic molecules
themselves, using chemical methods; ii) detecting some part ofthe
molecules by immunological methods;
detecting the activityof the toxins, called bioassays. Lehane and
Lewis (2000) give a review of different methods used to identify
ciguatera toxins.
Usually, methods that aim at identifying the toxins themselves are not
very user-friendly since they require specialized lab equipment and
personnel for separation and detection; for example, chromatography
for separation of toxins from the rest of the molecules in the crude
extracts and fluorescence for detection (Franco and Fernández-Vila,
1993; Lawrence et al., 1991).
Immunological methods are usuallyeasy to use and render fast
results.Monoclonal antibodies have been used to develop methods to
identify, among others, ciguatera toxins (Hokama et al., 1985, 1998),
PSP and ASP toxins.
Jellet Rapid Test kit for the detection of PSP toxins which takes
about 20 minutes (Jellet et al., 2002; Laycock et al., 2000). A
similar kit has been developed for ASP and others are under
development for other toxins. The kit is considered to be
user-friendly and good for in situ and preliminary screenings (Jellet
etal., 2002, Overrein, Asp and Aune , 2002). The most common problems
with these types of techniques are that the part of the toxin molecule
that elicits the reaction with the antibody may be altered in the
sample (for example,due to cooking) with corresponding variation in
the response (it may be a weaker positive); there may also be
differences in the chemical structure of toxic molecules from
different geographical locations, and the antibodies may fail to
givecomparable reactions with all of them (Jellet et al., 2002,
Overrein, Asp and Aune , 2002).
The third type of analysis is called bioassay because it aims to
identify the toxins by detecting theireffects. Louzao et al., (2001,
2003) have described a method to detectPSP toxins which measures
changes in the membrane potentialof excitable cells, which are
detected by a fluorimetric method. Basically, excitable
(neuroblastoma)cells are incubated with a fluorescent dye, whose
distribution across the membrane is potential-dependent, and with the
sample under examination. If the sample contains PSP toxins, the toxin
opens the Na -channels of the cellular membrane, depolarizing and
inducing a change in the membrane potential and a consequent change in
the measured fluorescence (Louzao et al., 2001). The method has been
later modified to be used on a microtitre plate, which makes it more
user-friendly and susceptibleto automation (Louzao et al., 2003).A
similar method, also using neuroblastoma cells has been developed to
detect ciguatera toxin(Manger et al., 1995), but in this case the
membrane depolarization is detected by change in color in the medium:
neuroblastoma cells are incubated with a tetrazolium compound (MTT)
which is reduced by healthy cells to a blue formazanproduct. No change
in colour is registered if MTT is incubated with dead cells: when the
neuroblastoma cells are incubated with samples containing ciguatera
toxin, the toxin binds to the Na channel receptors on the cells,
thusdamaging the cells and preventing them from reducing the MTT and
therefore no colour change is noticed.