12
EDUCATION
monday, AUGUST 20, 2012
Kingfish, another dwindling marine resource in Oman?
Regional strategy to sustain the kingfish needed
O
mani people love to
consume fish. In fact,
they are the highest
consumers of marine fish in
all GCC countries, consuming
on average 38 kg annually per
person. The kingfish or kan’ad
as it is known locally, is the
most sought-after table fish by
Omanis. This is no surprise as
kingfish meat is an excellent
delicacy. The importance of
kingfish as part of an Omani
diet had prompted the government in the early 1980s to ensure its sustainable harvesting
for current and future generations.
Wise management of fish
stocks relies a great deal on
sound scientific knowledge
of the fish species being harvested. With this view in mind,
SQU and under His Majesty’s
Trust Fund Grants has attained
the necessary research funds
for a research project aimed
specifically to gain the basic
and more advanced knowledge
on the biology, population dynamics and harvesting status of
kingfish in Oman. The project
was carried out by a team of researchers, headed by Dr Anesh
Govender, at the College of
Agricultural and Marine Sciences. It involved collecting
fundamental biological data
on kingfish, such as the weight
of individual kingfish caught,
where they are caught, and the
sex of the fish. More importantly, kingfish were dissected
to remove their otoliths, which
are very tiny calcified tissue
found in the inner ear of fishes.
The researcher elaborated
that otoliths were used by SQU
researchers to determine the age
of kingfish caught in Oman. He
at which they died naturally
and the rate at which they were
depleted through fishing. The
above factors would then be
used in mathematical models
to determine the status of kingfish in Oman. In other words,
fisheries managers could use
the model to determine whether kingfish in Oman is overexploited, underexploited or
optimally exploited. Optimal
A section of a kingfish otolith embedded in resin as
viewed under a microscope
added that determining the age exploitation is a target referof kingfish was important as ence point as it ensures that fuit revealed the time taken for ture generations of Omanis will
kingfish to reach sexual ma- still be able to enjoy kingfish in
turity, what ages they grew to their homes, he suggested.
and more importantly the rate
SQU’s research shows that
Degree which he successfully the fact that Omani fishermen
defended.
are targeting known spawning
Dr Govender pointed out grounds. Spawning grounds
that dwindling or scarce marine are areas were male and female
resources mean rising prices. kingfish aggregate to breed.
In 1988, a 5 kg kingfish would To date we have not been able
have cost the consumer RO to identify these grounds. The
1.85. Today the same fish can selective removal of large febe bought for between RO 14 males from the population
to RO 20, depending on the sea- has dire consequences. It may
son and region. He added that result in recruitment failure
mounting prices of kingfish had which implies that there are
also an impact on their research not enough parent stock to adat SQU. “The high costs for the equately restock new kingfish
purchase of kingfish samples fry in future years. The invesresulted in small sample num- tigation has shown that this is
bers in our research that may just what is currently happennegatively compromise our re- ing. “Visit any fish souq and
search findings”.
you will see smaller and smallIn an effort to determine the er kingfish for sale, a classic
best sample size, taking into sign of recruitment failure as
account labour and sample pur- a result of overfishing”, the rechase costs, Badria Yousuf al searcher said.
Siyabi undertook a simulation
What the future holds for
study to determine the optimal kingfish does not depend ennumber of kingfish to sam- tirely on Omani fishermen and
ple in a year. Her simulation fisheries managers alone, the
study was not an easy endeav- scholar remarked. Oman shares
our as she had to develop her the kingfish stock with many
kingfish is heavily exploited own programming software to neighbouring countries like
and that there is a likelihood undertake these analyses and Yemen and the UAE, and other
that their stock will collapse
economically in the coming
years (like abalone and rock
lobster). Applying various
mathematical and computer
models, SQU showed that the
dwindling numbers of kingfish
can be marginally increased by
implementing a closed season
for fishing. A closed season
reduces the fishing mortality of
the fish, allowing the species to
replenish itself. This fisheries
management option is still being scientifically debated.
To support this debate, and
under SQU’s kingfish project,
Abdullah Helal al Balushi undertook a survey of fishermen
and fisheries managers’ views
Dr Anesh Govender and Badria Yousuf al Siyabi
regarding the kingfish stock.
His survey results show that the simulation involved about GCC countries. There has to be
both groups of interviewees 5,000 computer runs which some regional management of
agreed that currently kingfish took about a week to complete kingfish, with all countries reharvested in Oman is biologi- and analyse. Nevertheless she sponsibly managing their kingcally unsustainable and that found that precision increases fish stock to the benefit of all.
This is a political chalthe current legislative rulings only marginally after a sample
lenge that can only be agreed to
are insufficient to ensure their size of 600 kingfish.
This finding significantly around a table and discussions
long-term sustainability. Moreover, he found that the role of reduced our sampling costs. on kingfish must be based on
traditional Omani management She successfully submitted this sound scientific knowledge.
To this end SQU is leading the
(Senat Al Bhar “Code of the study for a Masters degree.
The research has also re- way and has contributed conSea”) at the village or local level was diminishing and should vealed that more female king- siderably to the local and world
be revived. This research was fish than males are caught. knowledge on kingfish, he consubmitted by him for a Masters This is probably a result of cluded.
An integrated greenhouse
cooler and solar still
A
n SQU research
team is embarking
on a project aimed
at studying the possibility of
having an integrated system
of a greenhouse cooler and
solar still for the purpose of
providing the greenhouse
with its water demand in
places where freshwater is
absent and the dominant
water source is seawater or
saline groundwater.
Dr Abdul Rahim al
Ismaeli, the principal
researcher, says the solar
still will be made of two
glass compartments;
top and bottom.
Radiation-absorbing
material, like charcoal,
will be used to cover
the floor of the bottom
compartment to enhance
radiation absorption
and consequently water
evaporation.
He adds that cold
freshwater leaving the
greenhouse cooler, that is,
cooling pads, is pumped
to the top compartment
for pre-heating it before
reaching the bottom
compartment.
The pre-heated water
then flows through the
charcoal which makes
it gain more heat and
evaporates. This water
vapour then condenses
on the bottom surface
of the top compartment.
The latent heat of
condensation is absorbed
by the feed water. Finally,
the condensate flows to a
collection trough and can
be used to irrigate the crops
inside the greenhouse.
The team is working at
the College of Agricultural
and Marine Sciences to
develop a mathematical
model simulating the
evaporation process
of the greenhouse
evaporative cooler, water
preheating process in the
top compartment, and
the evaporation process
followed by condensation of
water vapour in the bottom
compartment.
Such a model should be
able to predict the amount
of condensate.
The results obtained
from the experiments on
the integrated greenhouse
cooler-solar still system
will be used to validate the
developed mathematical
model.
If calibration is
required then part of the
experimental results will be
used for the calibration and
the other part will be used
for the validation, Dr Al
Ismaeli concludes.
Aroma of camel milk
A
new study is under way to identify the volatile
compounds that contribute to the aroma or flavour
of camel milk. Dr Zahir al Atabi, at the College of
Agricultural and Marine Sciences, will examine the effect
of pasteurisation process on the development or generation
of these volatiles. This will include a human sensory
evaluation for camel milk.
The Omani camels are multipurpose animals, the researcher says. The benefits of camels are in racing, meat
and milk. However, less attention is given to the camel
milk. There are some studies on the camel breeding and
camel meat in Oman. Camel milk is still not used on a
commercial scale in Oman. Developing such areas will
greatly help in the Omani food security. He remarked that
the aroma or flavour could be a barrier in accepting the
camel milk among the Omani community, adding that the
study could give an index on the possibility of using the
camel milk commercially.
Fractionation of basil oil
A
researcher at SQU is investigating the potentials
of cultivating certain genotypes of basil in Oman,
being a high-value essential oil crop. This is the first study
on productivity, oil content, and composition of a large
number of basil accessions originating from various parts
of the Oman.
Dr Ahmed al Maskari states that “there is a significant
interest among Omani farmers in basil as a prospective
new high-value essential oil crop; however, there are no
reports on basil productivity, essential oil content, and
composition in this region”. He adds that Oman has suitable climatic and ecological conditions for many species of
basil and other medicinal plants which have not yet been
explored.
Basil oil, extracted via steam distillation from the leaves
and other parts of the plants, is used in flavouring food,
dental and oral products, and as a fragrance in traditional
rituals and medicines. Basil oil contains bioactive constituents that are insecticidal. Oman is investing a lot of money
in importing these items.
“Now with sophisticated instrumental techniques in
place, coupled with the enviable plant resource there is
no reason why Oman can't compete with the world in this
field”, Dr Al Maskari points out.
Different basil species native to Oman will be collected
and cultivated under screen house as well as using hydroponic system. After cultivation, plant biomass will be
harvested and essential oil will be extracted using some
hydro-steam distillation apparatus. Thus, extracted essential oil will be used to carry out fractionation using semiautomatic fractionating columns. The quality of separated
components will be monitored through GC-MS analysis.
The results will be useful for developing a fractionation
method for commercial scale separations.