Built for a life under water
Do fish drink water?
An oft- repeated question about the fact regarding fishes living in water is ’Do fish drink water’.
Many of us are curious to know the reply.
The answer is “Yes” & ‘No”
While the freshwater fish doesn’t drink water- the marine fish drinks large
quantities of water.
Since the liquid in a freshwater fish’s body is saltier (dense) than the surrounding water, the freshwater
fish is in constant danger of soaking up water and swelling. As a result it doesn’t
drink water and what ever water enters in fish body through skin & gills is
carried to the kidney and used to flush out waste products in large quantities of
The marine (Salt-water) fish has exactly
the opposite problem
Salt-water fish’s liquids are less salty (dense) than surrounding water and fish is in constant
danger of dehydration. Thus the salt-water fish have to drink large quantities of
water to make up for what it loses through its gills & skin. Some of the salt
that it receives goes through the digestive tract and is excreted. While some salt
that it receives is passed through special gill cells back into the ocean. A salt-water fish seldom urinate.
How Fishes Swim?
Though shapes of fishes differ widely but in general they are boat shaped which
facilitate their movement in water. For a fish to move through aquatic medium, which
is incompressible, it actually push it aside. The fish can do this by wiggling back
& forth in a snake like motion, pushing water aside by the forward motion of
its head, first to the left than do the right, also with the curve of its body and
finally with its flexible tail. The water, tending to return to its original position,
now flows back along the fish’s narrowing side, closing in at the tail and
helping the fish to move forward.
Skate and rays move by undulation of their greatly enlarged sidefins, which gives
them appearance of flying through water some flattened fish crawl on the bottom
like sea robin while some crawl right out of the water on the beach like mud skipper.
The climbing perch and snakehead travel overland from pond to pond on their forefins.
Some fishes can fly in the air. They can skim above the water for nearly a minute
and if there is good breeze to lift them up they may reach a height of 10-20 feet,
planing from wave to wave with their greatly extended forefins held rigidly out
How A Fish Sees?
Most of us are aware that seeing under water is a different matter from seeing in
the air. Light is diffused and quickly fades to a dim twilight zone. Even in clear
water only relatively close objects can be sharply focussed. But this is the environment, the eyes of fishes must cope with, and
their adaptation to the medium is extremely ingenious. Their primary
need is to see movements and nearby shapes- and this they do to perfection with
their eyes set on the side of their head, many of the fishes can practically register
every thing that moves around them at any time. Needing no eyelids or tear ducts
in their liquid medium, they have evolved ways of coping with varying amount of
The eyes of most of the fishes are placed so widely apart that they are considered
to have monocular vision viz. each eye collects a separate un- coordinated image,
which overlaps the least. In addition, the retinas of a fish pass impulses only
to the side of the brain, opposite the eye, enhancing the monocular effects. Compared
to this man has a double advantage his eyes are placed in front of his head giving
him a wide field of overlapping vision. Man’s eyes sends simultaneously impulses
along nerves to both sides of the brain, resulting in true binocular vision.
Some fishes have another remarkable feature of having ‘Divided Vision’.
Fish like Anableps is
adopted in seeing above a below the surface. Each eye of this ‘four eyed fish’
is situated on top of the head in such a way that it can swim with half of the eye
out of water, often ducking in water or moistening the eyeball.
We can find age of fish by reading its Scale
From head to tail, fishes are generally covered by flexible armour of rounded overlapping
plates called Scales. These
are embedded in the inner layer of the skin and form an important covering. In addition
to this, fishes are further protected by a layer of mucous slime produced by numerous
invisible glands scattered all over the body, this mucous in antiseptic helping
to ward off bacteria and fungi as well as lubricating agent.
In size and thickness, scales may vary greatly, from those of mahseer, which is reported to have scales (Fish size
over 12 feet) as large as man’s head to the microscopic one of common eel.
Few fishes especially catfishes have no scales at all. In some fishes like trunk-fish,
scale are fused to form an inflexible box like covering or in pipe-fish and sea
horse, rows of connected bony plates
Scales also grow along with the fish and especially in fishes of temperate zone
leave a distinctive record of age and season. Since in the temperate zones, each
scale grows fastest during the summer, when the fish is getting the maximum feed
and this make possible to tell a fish age by counting growth rings on scale. Regarding
typology, fish scales are categorized in four types. The primitive placoid scales
found in shark, rays and skates are tooth like structure size of grains embedded
on sand paper.
Ganoid scales are present in few bony fishes. These are diamond shaped and attached
to each other by joints. These are coated with ganoin a substance, which gives the
fish appearance of polished ivory.
The most common scales are cycloid and ctenoid. The former has a comb like edge
while the later has a rounded border. Most fishes have one or the other types of
scale. They are arranged in over lapping rows and as they are thin light and flexible,
most fishes that have them are fast swimmers.
Fatty fish intake may lower mental decline
A new study has found that fish fat intake may play a role in brain functioning
in middle age. According to a report in Health Scout, the study o 1,613 men and
women between the ages of 45 and 70 in the Netherlands, which has a high diet in
fish, found the type of fat consumed plays a role in a person’s mental flexibility,
speed and overall functioning. Fatty fish include mackerel, salmon trout herring
and other Coldwater fishes, which are found in the icy waters off the northern European
Researchers from University Medical Center Utrecht found people who ate lots of
foods rich in omega-3 polyunsaturated fatty acids and consumed lots of fatty fish
generally had a lower risk for impaired brain functioning (19% less) and speed (28%),
compared to those who didn’t follow a similar diet.
‘We used really sensitive cognitive tests, and it surprised me that already
at that age you could see the association between diet and mental agility’,
said Dr. Sandra Kalmijn, of the Julius Center for Health Sciences and Primary Care/
‘It convinced me and reinforced for me the link we saw between lots of fish
and cognitive function’. Conversely, those with diets high in cholesterol
were found at a ‘ significantly’ increased risk of impaired memory (27%
higher) and flexibility (26higher). The findings appear in the latest issue of Neurology.
Because a decline in mental skills can appear decades before the onset of Alzheimer’s
disease, the study says it’s important to examine the effect of diet on cognitive
functioning in middle age (ANI).
The Tribune 4th February 2004
Fish as multi doctor
Take fish to enrich your BRAIN
t is widely believed that countries or communities who have a lot of fish in their
diet are more intelligent than the others. Sounds fishy? But it may well be true.
Researches have shown that certain nutrients that are vital for the development
of one’s brain are found in very high level in oily fish. The brain has large
amounts of a fatty acid known as decosahexaenoic acid (DHA), but unfortunately the
human body is incapable of producing this fatty acid to the quantity that the brain
requires. This is usually supplemented by including meat, eggs and fish, particularly
the oily ones, which are very high in DHA. Mackerel, sardines, herring, and tuna
are very high in DHA, whereas in fish like cod, plaice, and monkfish, this is found
only in their livers.Fish are rich in eicosapentaenoic acid (EPA) and docosahexaenoic
acid (DHA) and it is these polyunsaturated fatty acids, which provide the key. It
is suggested that the minimal dietary requirement for EPA and DHA should be about
200 mg/day and this amount can easily be obtained from eating fish just once a week
In extensive researches done on primates and rats fed on food, rich in DHA, it has
been found that in all cases the learning abilities improved. Certain rise in visual
awareness was also noticed. From such experiments it has been concluded that DHA
improves eyesight, blood circulation and skin and reduces pain such as in rheumatoid
Take fish to protect your HEART
At one of the annual American Heart Association meeting in New Orleans, the Brigham
and Women's Hospital doctors presented their findings, which said that Omega-3 fatty
acids found in so-called fatty fish such as the salmon, mackerel, tuna and sardines,
seems to get into the tissues and arteries and aids in protecting the heart. They
said that eating fish at least once a week could cut the chances of dying suddenly
from heart failure into half. These findings were based on researches followed on
more than 22,000 male physicians for 12 years. It was found that those who ate at
least one serving of fatty fish a week reduced their chances of cardiac arrest by
50 percent. However, although consumption of fish was said to aid in reducing the
risk of sudden death, it did not seem to change drastically with the increase in
consumption. In other words, although eating fish once a week seemed to work, eating
it more often did not work better. The Omega-3 fatty acids protect the heart in
several ways. From keeping the heart beating too fast, they prevent the formation
of blood clots and also prevent the buildup of plaque in the heart arteries.
Take fish to control Blood Pressure (BP)
Eating fish regularly with omega 3 polyunsaturated fatty acids is said to significantly
lower blood pressure in people suffering from hypertension. According to a group
of doctors from John Hopkins Medical School, USA, 3 grams or more per day of fish
oil (6-10 capsules) lead to reduction in the blood pressure in hypertensive individuals,
lowering systolic pressure by an average of 5.5 mm Hg and diastolic pressure by
3.5 mm Hg. It is more effective in individuals who have really high blood pressure
and not in the ones having normal BP.
Take fish to protect your self from Cancer
Scientists are now saying that including fish in your diet may even prevent certain
types of cancer. Although not yet conclusive as far as humans go, studies in animals
have found that those same fish fats rich in omega-3 fatty acids suppress cancer
formation So next time you plan your menu, be sure to add fish in it, at least once
Fish - How Good Are They For Us
Fish is one of the most popular food items of the non-vegetarians. It is nutritionally
rich and tasty. Fishes varies in shape, size, colour, skin, bone, and taste. It
is unique animal meat that is rich in essential fatty acids. They contain protein
and many other major nutrients. Fish is a staple food in many parts of India and
The taste of fish depends upon its origin, whether from salt or fresh water, its
fat content, and whether it is eaten fresh or preserved. I doubt there are any other
food items those are cooked such a varied ways and eaten. Fresh fish is taken as
steamed, baked, boiled, as various curies, roast, fries, grills, pickles, cutlets,
finger chips, biriyani etc. Among this curries and fries are the most popular Indian
preparations. Dry fish is taken as fries, chutney, and also in powder form.
Mumtaz Khalid Ismail
Fish- rich in essential amino acid
Fish is a good source of proteins and it constitutes about 17 - 20 %. Fish proteins
are good sources of all essential amino acids. Fish protein beings rich in lysine
and threonine supplement effectively with cereal proteins. Small fish eaten along
with bones are a rich source of calcium. The caloric value of the edible portion
depends upon its fat content and thus on the season. During the spawning season
the fat content may rise and the caloric value increases. Studies have proved that
eating fish decrease heart disease.
Scientists have also discovered that omega 3 fatty acids are essential for the healthy
development of the eyes and brain. Fish has been described as a food for the brain
but there is no reason to believe that a fish eating population is in any way mentally
superior to those who do not eat fish or those who are vegetarians.
Fish is a rich source of long chain n-3 PUFA which are biologically more active
than their parent member namely alpha linolenic acid in producing several health
benefits. Those who have a taste for fish are advised to take about 100 - 200 gm
of fish twice a week. Fish oil capsules that containing large quantity of long chain
n-3 PUFA are used in the treatment of hypertriglyceridaemia, thrombosis, and inflammatory
diseases. Oily fish such as mackerel and trout have been shown to relieve some symptoms
of psoriasis and should form a regular part of those patients diet. This may be
due to the omega 3 fatty acids or to the large amounts of vitamin D present in it.
Salt-water fish is rich in iodine, phosphorous and calcium. Those who eat regularly
salt-water fish generally will not have these mineral deficiencies. Fish also contain
mineral copper. Vitamin A and D is also present. The oil from shark, cod, and halibut
liver is very rich in these vitamins.
Search byte- for expecting mothers
According to university of Bristol, consumption of fish in later stages of pregnancy
prove to be very potent in innate development of baby. Research has proved that
the presence of omega-3 fatty acid in fish helps in the development of the nervous
system (brain) of the child. Reason behind it is the enhanced blood circulation
aids in increased blood supply to the placenta due to which fetus derives more nourishment
from maternal blood.
Fish oil source of instant energy
Fish oils are available in capsule and liquid form. The cod liver oils are derived
from cod and also from Pollock, satire, and whiting. Fish oils are from fish liver
and fish body. The oil extracted from the fish livers is deodorised and then vitamin
E and antioxidants are added to prevent it from going rancid.
The oil is an excellent source of vitamin A and D. Two teaspoons of cod liver oil
provide about 1200ug of vitamin A, 20ug of vitamin D and about 2gms of omega 3 fatty
acids. Because of high concentrations of these vitamins, cod liver oil has been
used to prevent and treat conditions such as xerophtalmia; an eye disease caused
by vitamin A deficiency and rickets a bone disease caused by lack of vitamin D.
Shark liver oils also contain squalene, which is utilised by the body to produce
cholesterol. Glyceryl, a substance present in shark liver oil ethers may help to
protect against cervical cancer. Fish body oils contain less vitamin A and vitamin
D but are rich in omega fatty acids.
Fish Oil Fight Diabetes
April 23, 2002 -- A compound found in fish oil may help those at risk for type 2
diabetes stave off the disease. A new study shows fish oil supplements appear to
improve the function of insulin -- the hormone responsible for sugar metabolism
-- in overweight individuals.
Louisiana State University researchers presented the results of their study this
week at the Experimental Biology 2002 conference in New Orleans.
About 17 million Americans suffer from type 2 diabetes, and 16 million may be at
risk of developing the disease in the next decade, according to government estimates.
The disease occurs when the body becomes unable to respond to insulin, which causes
blood sugar levels to rise to dangerous levels. It is more commonly seen in overweight
This differs from type 1 diabetes, which is usually seen in children that aren't
overweight. But in recent years, doctors have been seeing more type 2 diabetes in
children due to the rising epidemic of obesity in the U.S.
The study authors say previous research has shown that populations that eat a lot
of fish containing omega-3 fatty acids, such as tuna, salmon, and mackerel, have
lower rates of type 2 diabetes compared with those who eat less fish. That prompted
them to look at the effect of omega-3 fatty acids themselves on how the body uses
Researchers studied 12 overweight men and women aged 45 to 70 and gave them once-daily
supplements containing 1.8 grams of an omega-3 fatty acid known as DHA (docosahexaenoic
acid). All of the participants suffered from insulin resistance, a condition in
which the body doesn't respond normally to insulin and that often precedes type
After 12 weeks, researchers found 70% of the participants showed a decrease in insulin
resistance, and in 50% of the patients that change was significant, according to
researcher Yvonne Denkins, PhD.
She says the findings are only preliminary. Due to the small number of participants
in the study, much more information about the role of fish oil in preventing diabetes
is needed before any recommendations can be made.
Anyone who is considering increasing their intake of fish oil with supplements should
first check with their doctor since DHA can have a slight thinning effect on the
In addition, there are other proven ways to prevent type 2 diabetes in someone at
risk. Both exercise and the drug Glucophage have been shown to work in preventing
type 2 diabetes in people who are overweight and have high levels of insulin in
By Jennifer Warner WebMD Feature Archive
FISH FOR HEALTH & BRAIN
Research shows that trout and other oil rich fish can play a vital role in preventing
deaths from heart disease- and yet most of us fail to eat enough to do us good1.
Government health experts recommend that we eat one to two portions of fish a week,
one of which should be an oil rich fish such as trout which is high in omega-3 polyunsaturated
fatty acids2. Research indicates that it can cut the risk of fatal heart attacks
by lowering blood fat levels and reducing blood clotting.
UK consumption, however, is very low, despite the fact that coronary heart disease
is the most common single cause of death in the UK3. Figures from the British Nutrition
Foundation show that only a third of adults eat one small portion of oil rich fish
a week. The Institute of Optimum Nutritionists believes as much as 90 per cent of
the population is now deficient in Omega-3.
An average portion of grilled trout (flesh only) is 1558, which provides 1.838 grams
of Omega-31 - well within the weekly health guidelines of 1.5g a week2.
It's low in fat (a third of the fat of salmon) as well as being low in calories
(just 135 kcals per 100g)2. It's an excellent source of iron, calcium, selenium
and vitamins A, B1, B2, B6 and B12 and contains valuable natural oils that can help
keep the skin and hair in good condition.
It's also extremely tasty - and convenient. A delicious trout meal can take under
15 minutes to prepare and cook.
In addition to medical research into heart disease, there is growing evidence to
demonstrate the importance of Omega-3 in brain and retina development in infants.
Concern has been expressed about the adequacy of Omega-3 in the diet of pregnant
and breast feeding women1
Oil rich supplements have also been shown to alleviate some of the symptoms of rheumatoid
arthritis, producing beneficial changes in levels of fatigue, swollen and tender
joints, grip strength and mobility1.
Because rainbow trout is mainly farmed, there is year round availability in this
country. Most supermarkets now carry a wide range, including whole gutted trout,
trout fillets, chunky fillets, hot and cold smoked slices or fillets.
So don't miss out - pick up a trout and head for a healthier lifestyle.
- British Nutrition Foundation
Conference, 1 December 1999
- Coma Report (Committee
on Medical Aspects of Food Policy 1994)
- Diseases of the heart
and circulatory system are the main cause of death in the UK, accounting for 260,000
deaths in 1997.
EATING TROUT MAKES YOU BRAINY
Ever heard the Old Wives' Tale that eating
fish makes you brainy? Well, scientists today keep finding more and more evidence
that it may be true!
Trout is packed with Omega-3 oils, which
scientists say can improve your IQ!
60% of your brain is made of fat - and not just any fat, but very special kinds
Trout is high in Omega-3 oils, which generally get called "Good Fats" because they
contain the stuff that helps your brain repair and rebuild its brain cells.
Nowadays we eat very little food that's rich in Omega-3 oils, but to keep our brains
happy and working well, we need to eat food that contains a lot of Omega-3.
Trout is full of protein, which gives you
energy (good for building muscles!)
Trout contains essential vitamins and minerals
Trout is high in calcium (for healthy bones and teeth)
Trout is rich in iron (for healthy red blood cells)
Trout is rich in selenium (for a healthy heart)
Trout is a great source of vitamin A (for healthy skin, and help resits infection)
Trout is a great source of vitamin D (bones and teeth again!)
Trout is low in saturated fat
Trout is high in Omega-3 oils
British Trout Association, Bow Business Centre, London E3 2SE
Eating Salmonid fish cures diabetes in women
A study undertaken recently in Harvard University revealed that the more fish a
diabetic woman eats, the less likely she is to develop heart disease.
Many researches have touted the benefits of fish for preventing heart disease in
healthy women, notes the lead author of this study, Dr. Frank Hu, associate professor
of nutrition and epidemiology at the Harvard School of Public Health. His group
postulates that fish may benefit women with diabetes even more, since these women
face a greater risk of heart disease.
They found that diabetic women who ate fish five days a week had a 65% lower risk
for heart disease than diabetic women who never ate fish. ‘Even for diabetic
women who ate fish once or twice a week, there was a 40% lower risk of heart disease,’
The study sample was 5103 female nurses diagnosed with Type 2 diabetes and free
of cardiovascular disease or cancer. Not only were reported fish eaters less likely
to develop heart disease but fewer of them died.
Not all fish are created equal, Hu says. “ Dark-meat fish belonging to salmonid
family Salmon have more omega-3 fatty acids so they are probably more beneficial’.
Source: Reader’s Digest; 165:988:Aug.2004:28p.
Ten Golden Rules
for good fish health for observance by Trout Farmers
- Buy fish eggs or fingerlings
with known health status i.e. from a farm, which is under surveillance of Fish Health
- Keep an optimal density
of fish in the raceways 4-5 kg/m3 stocking density is generally the optimum one;
- The velocity of the
water should be double the length of fish being reared in the raceways;
- Daily fish ration has
the direct relationship with water temperature. Over feeding may give birth to severe
diseases besides poor economics or even loses;
- Good hygiene in the
raceways and their disinfections at proper intervals can save fish from various
- Ensure strict vigil
on the up stream water. It should be free from sewage and pesticide washings;
- Avoid unnecessary stress
to the fish from handling. Treatment and shorting be done by experienced /qualified
- Ensure regular health
- On any sign of disease
discontinue feeding and call for personal of Fish Health Service;
- All in- all out system
be observed. Entire facility / raceways be emptied and disinfected before the recruitment
of fresh stock.
Fish Oil Cures Brest Cancer
Omega-3 fatty acid present in fishes, which is useful for brain has now found capable
of formulating a potent medicine against breast cancer after it’s amalgamation
with an anesthetic, during recent studies conducted by a group of scientists.
Researchers from The Indiana University, New York have claimed formulation of an
effective medicine against breast cancer by mixing Omega-3 fatty acid with anesthetic
prophol. Both the components are capable of halting the multiplication of cancerous
cells. Apart from stopping the spread of cancer to other parts of the body these
also block the growth of secondary tumor. On the basis of a study report published
in journal of British’s Cancer Research the results of the medicine formulated
from these compounds against cancer are really encouraging.
Dr. Sara Rawling a researcher told that effects of two types of Omega-3 fatty acids
DHA & EPA have been studied. When these are mixed with prophol then the results
are encouraging. The use of this medicine not only stopped the growth of cancerous
cells but even some effected cells were destroyed. Principal Scientist Dr. Rafat
Siddiqui said on the basis of research results a patch or ointment can now be formulated.
He further said that there are now plans to formulate large quality of this medicine
for tests on animals. At present the tests have been conducted on cancer effected
cells and it can hardly he stated that how much effective it would be on cancer
effected ladies. Omega-3 fatty acid is found in Tuna, Salmon, Hering, Sardins, Mackeral
fish species, which apart from keeping the brain fully toned also controls the blood
cholesterol level. Scientist even say that use of Omega-3 fatty acid in diet can
save from Arthritis, Dermatitis and Asthma.
Courtesy: AMAR UJALA
Global collapse of fish species by 2048
With 29% Species Already In Decline, Over-fishing And Habitat-loss Will Result In
Lesser Seafood: Study
Washington: The world’s fish and seafood population will collapse by 2048
if current trends in habitat destruction and over-fishing continue, resulting in
less food for humans, researchers said on Thursday.
In an analysis of scientific data going back to the 1960s and historical records
over a thousand years, the researchers found that marine biodiversity-the variety
of ocean fish, shellfish, birds, plants and micro-organisms- has declined dramatically,
with 29% of species already in collapse.
Extending this pattern into the future, the scientists calculated that by 2048 all
species would be in collapse, which the researchers defined as having catches decline
90% from the maximum catch. This applies to all species, from mussels and clams
to tuna and swordfish, said Boris Worm, lead author of the study, which was published
in the current edition of the journal Science.
Ocean mammals, including seals, killer whales and dolphins, are also affected.
‘Whether we looked at tide pools or studies over the entire world’s
ocean, we saw the same picture emerging’, Worm said in a statement. ‘In
losing species we lose the productivity and stability of entire ecosystems. I was
shocked and disturbed by how consistent these trends are- beyond anything we suspected.’
When ocean species collapse, it makes the ocean itself weaker and less able to recover
from shocks like global climate change, Word said. The decline in marine biodiversity
is largely due to over-fishing and destruction of habitat, Worm said in a telephone
interview from Dalhousie University in Halifax , Nova Scotia .
The loss of biodiversity makes ocean ecosystems loss able to recover from the effects
of global climate change, pollution and over-exploitation, Worm said.
He linked a diverse ocean environment to a diversified investment portfolio. With
lots of different species in the oceans, just as with lots of different kinds of
investments, ‘You spread the risk around,’ Worm said. ‘In the
ocean ecosystem, We’re losing a lot of the species in our stock portfolio,
and by the we’re losing productivity and stability, by losing stability, we’re
losing the ability of the system to self-repair’.
This research shows we’ll have few viable fisheries by 2050,’ Andrew
Sugden, international managing editor of Science, told reporters at a telephone
news briefing. “This work also shows that it’s not too late to act.”
To help depleted areas rebuild, marine-life reserves and no-fishing zones need to
be setup, Worm and other authors of the study said. This has proven effective in
places including the Georges Bank off the US Atlantic coast, he said. With marine
reserves I place, fishing near the reserves can improve as much as four-fold, Worm
Beyond the economic benefits to coastal communities where fishing is a critical
industry, there are environmental benefits to rebuilding marine biodiversity, the
scientists said. Depleted coastal ecosystems are vulnerable to invasive species,
disease outbreaks, costal flooding and noxious algae blooms, they reported.
Certain kinds of aquaculture can also be beneficial, according to the scientists.
Courtesy: The Times Of
India 4th November 2006 .
November 03, 2006
Its findings are startling. A global study lead by Dalhousie’s Boris Worm
shows current trends projecting the collapse of all currently fished seafoods before
2050. The international group of ecologists and economists show that the loss of
biodiversity is profoundly reducing the ocean’s ability to produce seafood,
resist diseases, filter pollutants, and rebound from stresses such as over-fishing
and climate change. The study, published in the November 3rd issue of the journal
Science, reveals that every species lost causes a faster unraveling of the overall
ecosystem. Conversely every species recovered adds significantly to overall productivity
and stability of the ecosystem and its ability to withstand stresses.
“Whether we looked at tide pools or studies over the entire world’s
ocean, we saw the same picture emerging,” says Dr. Worm. “In losing
species we lose the productivity and stability of entire ecosystems. I was shocked
and disturbed by how consistent these trends are – beyond anything we suspected.”
The four-year analysis is the first to examine all existing data on ocean species
and ecosystems, synthesizing historical, experimental, fisheries, and observational
datasets to understand the importance of biodiversity at the global scale.
Every species matters
The results reveal global trends that mirror what scientists have observed at smaller
scales, and they prove that progressive biodiversity loss not only impairs the ability
of oceans to feed a growing human population, but also sabotages the stability of
marine environments and their ability to recover from stresses. Every species matters.
The good news is that the data show that ocean ecosystems still hold great ability
to rebound. However, the current global trend is a serious concern: it projects
the collapse of all species of wild seafood that are currently fished by the year
2050 (collapse is defined as 90 per cent depletion).
Collapses are also hastened by the decline in overall health of the ecosystem –
fish rely on the clean water, prey populations and diverse habitats that are linked
to higher diversity systems. This points to the need for managers to consider all
species together rather than continuing with single species management.
Fundamental change needed
“Unless we fundamentally change the way we manage all the oceans species together,
as working ecosystems, then this century is the last century of wild seafood,”
says co-author Steve Palumbi of Stanford University . The impacts of species loss
go beyond declines in seafood. Human health risks emerge as depleted coastal ecosystems
become vulnerable to invasive species, disease outbreaks and noxious algal blooms.
Many of the economic activities along our coasts rely on diverse systems and the
healthy waters they supply. “The ocean is a great recycler,” explains
Palumbi, “It takes sewage and recycles it into nutrients, it scrubs toxins
out of the water, and it produces food and turns carbon dioxide into food and oxygen.”
But in order to provide these services, the ocean needs all its working parts, the
millions of plant and animal species that inhabit the sea.
The strength of the study is the consistent agreement of theory, experiments and
observations across widely different scales and ecosystems. The study analyzed 32
controlled experiments, observational studies from 48 marine protected areas, and
global catch data from the UN’s Food and Agriculture Organization’s
(FAO) database of all fish
and invertebrates worldwide from 1950 to 2003. The scientists also looked at a 1000-year
time series for 12 coastal regions, drawing on data from archives, fishery records,
sediment cores and archeological data.
Can losses be reversed?
“We see an accelerating decline in coastal species over the last 1000 years,
resulting in the loss of biological filter capacity, nursery habitats, and healthy
fisheries,” says co-author Heike Lotze of Dalhousie who led the historical
analysis of the Bay of Fundy , Chesapeake Bay , San Francisco Bay , and the North
Sea , among others.
The scientists note that a pressing question for management is whether losses can
be reversed. If species have not been pushed too far down, recovery can be fast
— but there is also a point of no return as seen with species like northern
“The data show us it’s not too late,” says Worm. “We can
turn this around. But less than one per cent of the global ocean is effectively
protected right now. We won’t see complete recovery in one year, but in many
cases species come back more quickly than people anticipated — in three to
five to 10 years. And where this has been done we see immediate economic benefits.”
The study was based at the National Center of Ecological Analysis and Synthesis
(NCEAS), funded by the National Science Foundation, the University of California
and UC Santa Barbara.
What is a fish
A fish is a cold-blooded aquatic vertebrate, which swims with the help of paired
fins and breathes through gills. Fish constitute about half of all known vertebrate
What is a person who studies fish called: An
How are fish identified: A
combination of the number of characteristics such as position of mouth, scale counts,
general features, colour, maximum length and distribution are used idendification.
Difference between male and female fish - In
some species the males and females have different shaped bodies or different colouring;
in other species there is no visible difference and its appears at the time of breeding
How fishes breathe: Some
fish have lungs and breathe air, but most breathe through gills. Gills are made
up of thin sheets of tissue richly supplied with blood vessels. As water passes
over them dissolved oxygen is absorbed into the blood and waste products such as
carbon dioxide pass out into the water. The gills are protected by a large bony
plate called an operculum.
What is a lateral line: The
lateral line is a row of scales that most fish have along their sides, stretching
from their head to tail. Under these scales are a system of fluid-filled canals
and specialized cells, which transmit vibrations to the brain. The lateral line
helps fish to detect objects including predators and prey.
Why are fish slimy: Fish
secrete a type of mucus from their skin. This slime coating is important because
it provides protection against parasites and diseases, covers wounds to prevent
infection and helps fish move through the water faster. Some species release toxins
in their slime which ward off attacking creatures while others use their slime to
feed their young.
What do fish eat? Fish Diet: Detritus,
diatoms, aquatic macro-invertebrates (particularly insect larvae, crustaceans and
worms), molluscs, aquatic plants, algae, zooplankton, fish and their eggs, terrestrial
insects, water birds, turtles, frogs, snakes and mice etc.
What eats fish: Other fish,
birds (e.g. pelicans, cormorants and herons), snakes, turtles, crustaceans, some
insect larvae (e.g. dragonfly larvae), and humans. In other parts of the world there
are also animals such as wild cats, wild pigs and bears that feed on fish.
Where do freshwater fish live: Freshwater
fish inhabit all sorts of environments: streams, rivers, lakes, springs, lands,
lagoons, billabongs, backwaters, estuaries, swamps, dune lakes, reservoirs, ponds
and drains. Some freshwater fish also spend part of their lifecycle at sea.
Types of Tropical fishes:
Anabantids - The Anabantids
are fishes that belong to the families Anabantidae, Belontiidae, Helostomatidae
and Osphronemidae. They are also called "labyrinth fish" because of their auxillary
breathing organ called "labyrinth".
Catfishes- Catfishes are
indentifiable by the barbels around their mouths which allow them to locate food
in the dark. Instead of scales, the skin may be naked or covered with bony plates
("scutes").Types: Mystus seenghala, W. attu , H. fossislis, Clarias batrachus etc. Cichlids - Description - The
colours, shapes and sizes of cichlids vary enormously. Types: Angelfish
Cyprinids- Description -
Tropical aquarium cyprinids are divided into three main groups: barbs (which are
carp-like fishes), danios and raspboras. All cyprinids spawn through egg-scattering.
Loaches - Description -
Loaches are distinguishable by the erectile spine beneath the eye, which acts as
deterrent to predators.
Livebearers - Description -
This is very brief summary information about the fish. Everything else is on a separate
page. Types: Mollies, Swordtails, Guppies,
Platy, Millions Fish
Other Fish - Description -
This category comprises: Triggerfish
Did You Know - Fish Facts: Are
there more mammal, bird or fish species on Earth? Fish! It’s believed there
may be 28,000 different fish species.
What fish can walk on land? The
climbing perch. This amazing fish, native to India , can walk on land in search
of water when its water hole dries up. The world's largest lake trout was caught
on the Saskatchewan end of Lake Athabasca , Canada , and weighed in at 102 pounds.
Global warming killing marine life
[7 Dec, 2006 2054hrs ISTAP]
WASHINGTON: In a "sneak
peak" revealing a grim side effect of future warmer seas, new Nasa satellite data
find that the vital base of the ocean food web shrinks when the world's seas get
And that discovery has scientists worried about how much food marine life will have
as global warming progresses. The data show a significant link between warmer water
— either from the El Nino weather phenomenon or global warming — and
reduced production of phytoplankton of the world's oceans, according to a study
in journal Nature.
Phytoplankton are the microscopic plant life that zooplankton and other marine animals
eat, essentially the grain crop of the world's oceans.
Study lead author Michael Behrenfeld, a biological oceanographer at Oregon State
University, said on Wednesday that the recent dramatic drop in phytoplankton production
in much of the world's oceans is a "sneak peak of how ocean biology" will respond
later in the century with global warming.
"Everything else up the food web is going to be impacted, "said oceanographer Scott
Doney of the Woods Hole Oceanographic Institute. He was not involved in the study.
"What's worrisome is that small changes that happen in the bottom of the food web
can have dramatic changes to certain species at higher spots on the food chain,
This is yet another study with real-time data showing the much-predicted harmful
effects of global warming are not just coming, but in some cases are already here
and can be tallied scientifically.
10 small steps for a longer
New Year is a time many of us resolve to make dramatic health improvements, such
as joining the gym and giving up alcohol for ever (or for at least a month). But
some of the most dramatic changes we can make are incredibly simple.
Here with the help of leading experts, Good Health offers a guide to the ten easy
steps that really will make a difference to your life:
ONE: FLOSS Flossing
at least twice a day is essential to prevent decay says Dr Nigel Carter, chief executive
of the British Dental Health Foundation.
Too few people floss, putting themselves at risk of life-threatening diseases such
as mouth cancer and heart disease.
But choose proper dental floss - according to a recent national dental survey, more
than 60 per cent of Britons use screwdrivers, scissors and earrings to remove food
from between their teeth.
TWO: HAVE YOUR EYES TESTED:'
A thorough eye test is a health check that can detect underlying conditions that
leave you predisposed to sight loss,' says Ciara Smith, at the Royal National Institute
for the Blind.
'Around 1.9million people with diabetes aren't having the regular eye tests they
need, while 250,000 people with early-stage glaucoma are at risk of losing their
sight but don't realise it.'
So get your eyes tested at least every two years.
THREE:EAT 'GOOD' BACTERIA: 'Good'
bacteria - or probiotics - are essential for our digestive health and helping the
immune system to work.
In certain circumstances, for example prolonged use of antibiotics or a severe bout
of vomiting or diarrhoea, the gut is stripped of its good bacteria. One of the best
sources of probiotics is natural yoghurt.
You can buy other products which say they include probiotics, although some contain
only one of two strains of good bacteria rather than the hundreds needed. A good
health food store will advise you.
FOUR: TAKE A CHOLESTEROL
TEST: Coronary heart disease is the biggest killer in the Western
world. In the UK it accounts for one in four of all male and one in six of all female
Professor Peter Weissberg, medical director of the British Heart Foundation (BHF),
says everyone over 40 should know their cholesterol level and then aim to reduce
'You can't have too low a cholesterol level,' he adds. 'In the UK we regard 5.5
as an average reading, although in other countries, such as China, this is considered
very high - and they have a low rate of heart disease compared to us.'
Ask your GP or practice nurse for a simple blood test. Or you can buy a cholesterol
test over the chemist's counter, but make sure you choose one with separate readings
for good (HDL) and bad (LDL) cholesterol levels: if the results show a high reading,
see your GP.
FIVE: STOP SLOUCHING: Better
posture is the single most effective weapon against chronic back problems, says
Matt Todman, consultant physiotherapist at the Sports & Spinal Clinic in Harley
He recommends taking up Pilates if you are prone to the problem, but simply stopping
your slouch habit at your desk and not lugging around heavy bags can make a huge
SIX: SWITCH TO UNSALTED BUTTER: The
recommended amount of salt per day is 6g, but most of us routinely consume around
9g. Cutting your salt intake by one teaspoon a day can halve your risk of coronary
heart disease, the UK's biggest killer.
Check food labels. Choose those with low salt or sodium content - 0.25g of salt
per 100g of food, or 0.1g sodium per 100g. Just switching to unsalted butter, for
instance, could make a difference in the long term - or remove the salt cellar from
SEVEN: EAT A CAN OF SARDINES
A WEEK: Omega 3 fatty acids in oily fish (such as sardines, tuna
and herring) play an important part in the development of the central nervous system
- and in countering a range of conditions including heart disease and Alzheimer's.
The Food Standards Agency says we should each try to eat two portions of fish a
week, one of them oily.
EIGHT: REDUCE YOUR WAISTLINE: A
recent study found that people who had the biggest tummies were 40 per cent more
likely to suffer from a heart attack, and that the waistline was a better indication
of health than your Body Mass Index.
Women should have a waistline of less than 31.5 inches and men 37 inches. The simplest
way is to lose weight overall, and the BHF recommends aiming for a loss of just
2lb a week over the long term.
NINE: SQUEEZE YOUR PELVIC
FLOOR MUSCLES : One in three women in the UK suffers from urinary
incontinence - but the embarrassing nature of the problem means many never see a
'Urinary incontinence can disrupt a person's social life and thousands become clinically
depressed because of it,' says Dr Sarah Jarvis, women's health spokesperson for
the Royal College of GPs.
Doing regular pelvic floor exercises improves bladder control. First, squeeze your
pelvic floor muscles as if you were trying to hold back urine. Then tighten these
muscles and hold for a few seconds. Repeat this ten times, and do the whole exercise
at least four times a day.
If you suffer from incontinence, ask your GP to refer you to a specialist nurse.
For more advice, call 0870 770 3246 or visit www.incontact.org.
TEN: STOP MAKING PLANS: 'Live
in the moment,' says psychotherapist Derek Draper. 'The new year is a time when
people reflect on the past and make plans for the future, but if you have too many
regrets or set yourself unachievable goals, you'll end up disappointed.'
A review by the U.S. National Academy of Science showed increased 'mindfulness'
- the psychological term for living in the moment - led to less stress and boosted
the immune system.
A review by the US National Academy of Science shows increased’ mindfulness’,
psychological term for living in the moment, leads to less stress and boosts the
Courtesy: Daily Mail, London.
Fish oil fights weight loss from chemotherapy
diet with fish oil may prevent muscle and weight loss that commonly occurs in cancer
patients who undergo chemotherapy.
The process can cause cancer patients to lose muscle mass and become malnourished,
leading to fatigue, a decreased quality of life and shorter survival.
Researchers believe that supplementing the diet with fish oil - which contains omega-3
fatty acids such as eicosapentaenoic acid - may help patients maintain or gain muscle,
the journal Cancer reports.
Vera Mazurak of the University of Alberta in Edmonton, Canada, led a team that compared
the effects of fish oil with that of standard care (no intervention) on weight,
muscle, and fat tissue in newly referred non-small cell lung cancer patients.
Patients who did not take fish oil lost an average of 2.3 kilograms whereas patients
receiving fish oil maintained their weight, according to an Alberta University release.
Patients with the greatest concentration of fish oil supplementation in the blood
had the greatest gains in muscle. Sixty-nine percent of patients in the fish oil
group gained or maintained muscle mass.
Comparatively, only 29 percent of patients in the standard care group maintained
muscle mass, and overall, patients in this group lost one kilogram of muscle. No
difference in total fat tissue was observed between the two groups.
"Fish oil may prevent loss of weight and muscle by interfering with some of the
pathways that are altered in advanced cancer," said Mazurak. IANS
Omega-3 fatty acids keep blindness at bay
Previous research has shown that omega-3 fatty acids – commonly found in fish
oil – can prevent retinopathy, a major form of blindness that affects people
with diabetes and premature babies, in a mouse model of the disease. Now a follow-up
study, from the same research team at Children's Hospital Boston, has revealed how
exactly omega-3 fatty acids help prevent several forms of blindness.
It also provides reassurance that widely used COX-inhibiting drugs like aspirin
and NSAIDs do not negate their benefit. The results showed that omega-3 fatty acids
could prevent eye blindness such as retinopathy, caused by the proliferation of
tortuous, leaky blood vessels in the retina, and age- related macular degeneration
(AMD), caused by abnormal growth of blood vessels. Previous research by Children's
Hospital ophthalmologist Lois Smith and senior investigator of the new study had
shown that mice fed diets rich in omega-3s had 50 percent less pathologic vessel
growth in their retina than mice fed diets rich in omega-6 fatty acids. In their
new study, Smith and her colleagues documented another protective mechanism - a
direct effect on blood vessel growth (angiogenesis) that selectively promotes the
growth of healthy blood vessels and inhibits the growth of abnormal vessels. They
isolated the specific compound from omega-3 fatty acids that has these beneficial
effects in mice (a metabolite of the omega-3 fatty acid DHA, known as 4-HDHA), and
the enzyme that produces it (5-lipoxygenase, or 5-LOX). The researchers also found
that COX enzymes are not involved in omega-3 breakdown, suggesting drugs such as
aspirin or NSAIDs do not affect the benefits of omega-3.
"This is important for people with diabetes, who often take aspirin to prevent heart
disease, and also for eld erly people with AMD who have a propensity for heart disease,"
said Smith. Smith is currently working alongside the US National Eye Institute,
which is conducting a trial of omega-3 supplements in patients with advanced macular
degeneration, expected to conclude in 2013.
The findings are published in the current issue of Science Translational Medicine.