Minggu, 26 Februari 2012

Sabtu, 25 Februari 2012

Iwak glodog

Scorpion fish

Mahseer lake kenyir

Melem

Thailand mahseer

Wolfish

Piranhas are pussycats! The Hoplias of South
America are the predators to really fear, says
Oliver Lucanus.
No freshwater fish has a more fearsome reputation
than the piranha, but, as many aquarists soon
learn, these are actually quite timid. They get
nervous when the aquarium is approached and
prefer to bite pieces of other fishes' fins rather
than devour them whole.
However, South America is home to another group
of fish that are far more voracious and much more
aggressive. This is the family of the Amazon
wolffishes and they have many names, including
TrairĂ£o (sp.'Trai-ron'), Aimara, Guabina and
Fasaco.
They are part of a characoid sub-family of 16
species, found from Costa Rica to Argentina in
nearly every kind of water. Because the wolffish
can breathe air it can survive where few others
could. In the dry season it's not unusual to find
Hoplias the last survivors in an emptying pool.
The wolffish family has something for everyone:
Hoplerythrinus unitaeniatus, the smallest, will
reach just over 20cm/8", while the largest (Hoplias
aimara) will reach 130cm/51" and more than
30kg/66lb.
Despite their reputation wolffish can be good
aquarium fish and are surprisingly interesting with
other fish or in groups. Special rules apply, but
these fish are hardy and easy to maintain.
Classification
The sub-family consists of three genera, totalling
16 species. The largest group is the genus Hoplias
with 11 species and we assume that H. aimara and
macrophthalmus are separate species, although H.
macrophthalmus may be a synonym.
Next is Hoplerythrinus with three species, and
Erythrinus with two.
Within their genus the species are similar and
you'll need to know where your fish were collected
to have an idea of what species belong where.
Brazil, Colombia and Venezuela don't export their
wolffish species, so the list narrows.
Several others are highly endemic and have rarely
been exported. Assume that an aquarium wolffish
belongs to one of five species.
Hoplerythrinus unitaeniatus is easily identified by
its single horizontal stripe and elongate body, and
exported occasionally from Peru and Colombia. It
can be kept in a small school in a large aquarium.
Unlike Erythrinus and Hoplias these wolffish hunt
in roving packs, cornering groups of smaller fish,
especially characins, or chasing crustaceans and
insects in the substrate or along the surface.
Their swimbladder is not as reduced as much as
the other genera, so they are much more surface
oriented and active than other wolffish. They can
also do well in a community tank with other larger
fishes such as catfishes, cichlids and larger
characins, such as Myleus and Leporinus.
Hoplerythrinus will accept dry foods such as
pellets, freeze-dried shrimp and insects, and
sometimes even flake foods more readily than
their relatives.
All wolffish are excellent jumpers and any
aquarium must be covered at all times!
Hoplerythrinus also prefer flood zone habitats
with mild or no currents and several hundred
individuals can migrate deep into flooded plains
or forests during the rainy season.
The other small species occasionally found in the
hobby is Erythrinus erythrurus, often called the
Redfin wolffish. Juveniles especially can show
attractive red, yellow and even purple hatch marks
on their flanks over an overall brown or burgundy
body.
Margins of the unpaired fins can be bright red,
yellow or white. The body shape is more stout
than Hoplerythrinus and the swimbladder is
reduced much further — to the point that the
species swims in open water only when it wants to
grab prey from the water column.
Erythrinus are more solitary, so groups require
large aquariums with plenty of hiding places,
allowing each fish to claim a territory. Short
lengths of clay or PVC pipe make ideal caves for a
relatively shy fish that may fight with conspecifics.
Fish that do not challenge them for territory and
do not fit in their mouth are usually ignored.
Ideal tank mates are sturdy characins such as
Myleus and Metynnis. Large-bodied cichlids such
as Astronotus, Hoplarchus and Cichla also fare
well.
Slow catfish risk having their eyes bitten when
entering caves occupied by wolves.
Erythrinus will feed on live fish, crustaceans,
worms and insects, and only slowly get used to
frozen foods.
Erythrinus is found in swampy shoreline habitats
and shallow clear or blackwater streams deep
inside the forest. Besides insect larvae, all
examined had Apistogramma, Moenkhausia and
Nannostomus in their stomachs.
Most interesting are Hoplias. Usually only three
species are exported for the hobby and most
common is H. malabaricus, being widespread in
both the Amazon and Orinoco lowlands and
exported frequently from Peru.
Any wolffish bought in an aquarium shop will
probably belong to this particular species.
Colour can range from mottled grey to brown and,
depending on place of origin, almost black.
Juveniles are usually lighter and have bright yellow
or green eyes.
In nature they are solitary, found in slow moving
waters of virtually any habitat. The smaller the fish
the shallower the habitat, and it's not unusual to
find finger-long H. malabaricus in less than
5cm/2" of water, stalking aquatic insects and
small fish. As the fish mature they become less
tolerant of each other and move to deeper water.
Adult H. malabaricus are not overly aggressive,
but require a larger territory. Along riverbanks
adults are usually spaced 3-4m/10-13' apart.
As with all wolffish species, aquarium water
chemistry is of little importance, as these fish can
adapt to just about any common range of values.
Hoplias malabaricus are lazy, moving only when
food is added to their environment. Juveniles will
eat virtually any frozen or live food, but do well
with frozen Mysis, smelt or cocktail shrimp.
They are often more active at dusk and dawn, so
keep lighting subdued to allow them to show more
activity during the day. Kept as a group of equal
sizes they get along well until becoming sexually
mature at 20cm/8".
Minor injuries sustained in territorial fights
usually heal quickly. Large wild Hoplias are often
caught with severe injuries, missing eyes,
deformed jaws and amputated pectoral or ventral
fins, but seem otherwise normal.
As they mature, females develop a more robust
shape and rounded stomach. They will become
increasingly intolerant until a pair has formed,
then will usually get along well and lay close
together.
Breeding can usually be induced by first dropping
the temperature, raising it to 28-29°C/82-84°F and
slightly dropping the level of water.
During breeding the male digs shallow pits in
which 2,000-10,000 yellowish eggs are laid in a
cluster. He guards the nest and larvae until they
hatch and spread out in the shallow water to hunt
small prey.
In the aquarium the young will immediately eat
Artemia nauplii and grow rapidly, eventually
cannibalising each other.
The newest member of Hoplias is also the second
most imported species. It was known as Hoplias
sp. Black for many years and described as Hoplias
curupira in 2009.
This fish will occur sympatrically with H.
malabaricus, but usually occurs in a different
niche.
The black wolffish prefers river banks of faster
rivers, especially major tributaries of the middle
Orinoco.
The body is more stout and less elegant than H.
malabaricus and overall colour is a more uniform
black or dark brown. The eyes are usually equally
dark and less apparent. A maximum 30cm/12"
size is considerably smaller than the 45cm/18"
commonly reached by H. malabaricus.
Black wolffish seem to prefer large shrimp and
larger fishes. Stomach contents examined in the
Orinoco region revealed Macrobranchium spp
shrimp, juveniles of several cichlid species and
larger sized Leporinus.
Hoplias curupira are more aggressive, both to
each other and towards the keeper. It's is not
unusual to find one approaching the front glass
with flaring gills or viciously attacking any object
used to trap them.
Large wolffish can cause deep cuts to a keeper's
hands. Handle them with the same respect as a
powerful reptile of equal size. Such extreme
aggression also means the fishes can be fed
directly with large tweezers and the fish quickly
learn to take large cocktail shrimp or smelt from
them.
H. curupira will try to swallow fish almost up to
their own size and may attack larger fish. When
keeping them in a community aquarium choose
only robust tank mates of considerably larger size.
Breeding behaviour is not known in the aquarium,
but likely similar to other Hoplias species.
The fearless king
The most formidable Hoplias exported is the king
of wolffish: the aimara, or trairĂ£o (Hoplias aimara
and/or H. macrophthalmus). Juveniles and young
adults sport a small black spot behind the gill
cover.
It's much larger and aggressive than the others
and in nature is found in fast-flowing

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Iwak ki



Penangkar Arwana "Ibarat Pangkat Kopral Gaji Jenderal"

Selasa, 8 Maret 2011 23:57 WIB | 562 Views

Oleh Andilala

Jakarta (ANTARA News) - Penghasilan para penangkar ikan arwana jenis "Super Red" bisa dikatakan ibarat seorang prajurit TNI dengan pangkat kopral tetapi mendapatkan gaji setingkat jenderal.

Bagaimana tidak, seorang penangkar di Kecamatan Semitau dan Suhaid yang berada di kawasan Taman Nasional Danau Sentarum di Kabupaten Kapuas Hulu, Provinsi Kalimantan Barat per bulannya bisa menghasilkan ratusan juta rupiah dari hasil penjualan anakan ikan arwana jenis "Super Red" ke Kota Pontianak, yang kemudian diekspor ke China dan Jepang.

H Dulkarim (44), salah seorang penangkar arwana jenis "Super Red" di kecamatan itu hanya tinggal menunggu indukan arwana bertelur dan menetas hingga menjadi anakan ikan yang siap jual.

"Saya mulai mengembangbiakkan arwana sejak sepuluh tahun lalu dengan modal awal Rp20 juta, dengan membuat kolam secara manual dan membeli dua ekor induk arwana satu jantan dan satu lagi betina," ujarnya.

Kini Dulkarim yang bisa menunaikan ibadah haji dari penangkaran arwana itu telah memiliki delapan kolam ukuran 6 X 12 meter itu memiliki aset sekitar Rp1,5 miliar dengan asumsi Rp200 juta per kolam.

Satu kolam ada sekitar delapan hingga sepuluh ekor induk, tujuh betina dan tiga jantan. "Satu jantan arwana bisa mengawini dua hingga tiga betina, agar perkembangbiakannya cepat," kata ayah tiga anak tersebut.

Dulkarim mengatakan, budidaya arwana memang membutuhkan perawatan khusus dan memerlukan tingkat keasaman air dan tanah tertentu. "Asal tingkat keasamannya tetap terjaga maka tidak berpengaruh meski lokasi kolam berada di dekat kebun sawit," katanya.

Dulkarim menambahkan, dari hasil usaha budidaya arwana ia mampu menyekolahkan anaknya hingga di perguruan tinggi di Jakarta jurusan kesehatan dan mampu membeli dua unit mobil.

Dulkarim beberapa waktu lalu memanen anak ikan arwana sebanyak 200 ekor atau senilai Rp250 juta. "Untuk pemasaran tidak ada masalah, malah ekspor arwana kita ke Jepang, China belum memenuhi kuota," katanya.

Sementara Sukarman (43) salah seorang penangkar arwana di Suhaid mengatakan, dia menggeluti budidaya arwana baru dua tahun dengan modal kredit bank dan meminjam induk arwana milik keluarganya.

"Budidaya arwana butuh biaya besar, untuk membuat doa kolam saja saya merogoh "kocek" (saku) sekitar Rp50 juta, itu belum termasuk pengadaan induk yang per ekornya bisa seharga Rp15 juta untuk ukuran sedang," katanya.

Itu pun induk arwana tersebut harus dipelihara paling tidak satu tahun baru bisa menetaskan telur hingga menjadi anakan arwana, katanya.

"Genap dua tahun budidaya arwana saya sudah dua kali panen atau sebanyak 50 ekor dijual seharga Rp2,5 juta per ekor atau sebesar Rp125 juta," ujarnya.

Namun ia mengakui belum balik modal karena investasinya untuk dua kolam sekitar Rp300 juta.

Budidaya ikan arwana boleh dikatakan gampang-gampang sudah, karena tidak semua penangkar arwana di dua kecamatan itu yang sukses. "Malah ada beberapa kolam milik warga setempat yang sudah belasan tahun tetapi belum juga panen," kata Sukarman.

Satu induk betina arwana bisa menetaskan telur hingga menjadi anak paling banyak 30 ekor atau senilai Rp75 juta atau bersihnya separoh dari jumlah itu setelah dipotong pembelian pakan, dan satu induk dalam setahun lebih dari sekali menetaskan telurnya.

Camat Semitau Iwan Supardi mengatakan, di daerahnya terdapat sekitar 100 penangkar arwana, dengan rata-rata memiliki lebih dari dua kolam.

Menurut dia, budidaya arwana mulai gencar dilakukan awal tahun 1990-an, ketika ikan arwana endemik TNDS mulai habis diburu oleh nelayan dan warga sekitar danau itu karena harganya yang tinggi.

"Setelah ikan arwana sulit ditemukan, masyarakat mulai beralih membudidayakan arwana dengan membuat kolam, ternyata budidaya arwana di kolam berjalan lancar karena tingkat keasaman air dan tanah di Kecamatan Semitau dan Suhaid sama dengan kawasan TNDS," ujarnya.

Kini Camat Semitau itu juga telah memiliki empat kolam dengan rata-rata memiliki induk sepuluh ekor per kolam dengan aset miliaran rupiah.

"Saya memilih bertugas selamanya di Semitau agar bisa mengembangkan budidaya arwana. Selain hasilnya besar, budidaya arwana juga mengasyikkan dan tentunya mudah tidur ketimbang jadi kepala dinas atau ditugaskan di lingkungan Pemerintah Kabupaten Kapuas Hulu," kata Iwan.

Menurut camat yang sukses sebagai penangkar arwana itu, satu kolam dengan sepuluh ekor induk arwana bisa menghasilkan Rp40 juta/sekali panen dan per kolam. Dalam sebulan satu kolam bisa beberapa kali panen atau tergantung jumlah induk arwana betina.

Kecamatan Semitau dan Suhaid salah satu daerah penghasil arwana super red endemik Taman Nasional Danau Sentarum.

Dongkrak perekonomian

Wakil Kepala Bank Pembangunan Daerah (BPD) Kalimantan Barat, Cabang Semitau Burhanudin mengatakan, budidaya arwana salah satu pendongkrak perekonomian masyarakat di Kecamatan Semitau dan Suhaid.

Perputaran uang di BPD Kalbar Cabang Semitau terdiri dari sektor perkebunan karet sebesar 25 persen, penangkaran ikan arwana 25 persen, sektor perkebunan sawit 20 - 25 persen dan lain-lain, seperti tabungan, giro dan deposito 25 persen, katanya.

Menurut dia, meskipun penangkar arwana jumlah tidak banyak, tetapi sektor itu bisa menyumbang cukup tinggi bagi perekonomian masyarakat Semitau dan Suhaid.

"Karena dari budidaya arwana juga menyerap banyak tenaga kerja dan lapangan usaha laan seperi penyedian pakan ikan dan lainnya," kata Burhanuddin.

Bupati Kapuas Hulu AM Nasir mengatakan, pihaknya akan terus menjaga kawasan konservasi dan hutan lindung di kawasan TNDS agar semua sektor tetap bisa berjalan sebagai mana mestinya.

Ia mengingatkan investor pengembang perkebunan sawit di kabupaten itu tidak masuk atau menabrak kawasan hutan lindung dan konservasi, agar di satu sisi sektor perkebunan sawit dan karet tetap berjalan, di sisi lain kawasa TNDS dan hutan lindung lainnya tetap terjaga sehingga tidak mempengaruhi budidaya arwana yang menjadi kebanggaan Kapuas Hulu hingga di tingkat mancanegara.

"Semua wajib menjaga kawasan hutan lindung agar kelangsungan TNDS sebagai hutan HoB (Heart of Borneo) atau hutan lindung di Kapuas Hulu sebagai paru-paru dunia tetap terjaga hingga anak cucu kita," katanya.

Ia mengatakan luas Kapuas Hulu sekitar 29.850 kilometer persegi, 52 persen di antaranya sudah dialokasikan untuk kawasan konservasi.

"Kami tidak menginginkan kawasan hutan lindung dan konservasi tidak dirusak lagi pascamaraknya pembalakan hutan tahun 1980," ujar Nasir.

Nasir mengancam jika ada pengembangan perkebunan sawit yang masuk kawasan hutan lindung dan hutan konservasi, akan dicabut izinnya.

"Dalam waktu dekat kami akan mengevaluasi semua pengembangan sawit di Kapuas Hulu, kalau ada melanggar kami cabut izinnya," kata Bupati Kapuas Hulu.

Sementara itu, Pimpinan Sinar Mas Group Wilayah Kalimantan Barat Susanto menyatakan, pihaknya tetap berkomitmen menjaga kawasan hutan lindung dan konservasi.

"Malah kami dengan inisiatif sendiri meminta kajian dari BPKH untuk tidak memasuki kawasan hutan lindung, taman nasional, hutan produksi, hasil kajian areal yang masuk itu segera diajukan ke bupati untuk direvisi," ujarnya.

Selain tidak menanami hutan lindung dan konservasi Sinar Mas Grup meminta instansi terkait melakukan tata batas antara kawasan perkebunan dengan areal hutan lindung dan konservasi.

"Kami juga membuat papan peringatan yang berisi larangan menebang, membakar dan berburu terhadap satwa yang dilindungi di setiap sudut kawasan hutan lindung," ujarnya.

Ia menyadari fungsi hutan sebagai penyerap karbon tetap harus dijaga demi menjaga keseimbangan alam dan untuk kehidupan bagi generasi mendatang.

Susanto menyampaikan terima kasihnya kepada Pemkab Kapuas Hulu dan masyarakat di kabupaten itu sehingga bisa mengembangkan perkebunan sawit di kabupaten itu.

Sebelumnya, Eldimart Controler PT KPC mengatakan, pihaknya memang menerapkan penggunaan pestisida dengan sistem tepat dosis, tepat cara, tepat waktu, serta menerapkan prinsip ramah lingkungan sehingga tidak mengganggu budidaya arwana.

"Selain komitmen kami agar tidak mengganggu budidaya arwana, penggunaan pestisida juga dilakukan dengan hati-hati dan sesuai prosedur yang berlaku," katanya.

TNDS selama ini dikenal sebagai perwakilan ekosistem lahan basah danau, hutan rawa air tawar dan hutan hujan tropik di Kalimantan. Danau musiman yang berada di TNDS terletak pada sebelah cekungan sungai Kapuas, sekitar 700 kilometer dari muara yang menuju laut China Selatan.

Itu merupakan daerah tangkapan air, sebagai pengatur tata air bagi Daerah Aliran Sungai Kapuas. Daerah yang terletak di hilir Sungai Kapuas sangat t

Senin, 13 Februari 2012

Senin, 06 Februari 2012

Minggu, 05 Februari 2012

Giant aquarium features a lift in the centre



Giant aquarium features a lift in the centre

Giant aquarium features a lift in the centre

Copyright © ICM

A massive new shopping mall in Morocco has installed an equally gigantic marine aquarium as its centrepiece and customers can now dive to its bottom without getting wet!

The huge, conical aquarium was designed and built by the American company International Concept Management (ICM) for the Morocco Mall in Casablanca and is called 'Aquadream'.

The vast, freestanding tank stands 9.3m/31' tall and holds around one million litres/264,000 gal. of water.

Made from acrylic panels over 12cm/4" thick, the main tank has a diameter of 13.4m/44' at its top and inside this is a smaller 3.4m/11' tube which contains a lift in which shoppers can travel to the bottom of the tank, exploring the underwater world and its inhabitants.

'Aquadream' contains over 3,000 fish and the five-minute lift ride is designed to be an educational experience, allowing customers to come face to face with at least 41 species of fish, including sharks and rays, from the comfort and safety of the glass sided lift, however more adventurous shoppers can choose to pay to scuba dive inside the tank instead.

Due to the potential for seismic activity in the area, the tank is seated on its own, independent concrete slab which helps cushion it against tremors while at the same time isolating it from any movement the mall itself may experience during quakes. This safety feature was tested successfully during the tank installation by two minor tremors, neither of which damaged the tank or its support systems.

The filtration systems are vast, filtering the entire tank's contents hourly, but despite Morocco Mall's close proximity to the Atlantic Ocean the tank is filled using freshwater and artificial sea salt.

Decor for the tank takes the form of a realistic looking coral reef, constructed from concrete rockwork covered in over 3,500 artificial corals.

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.



Published: Bob Mehen Monday 30 January 2012, 10:11 pm
Views: 1,881 times

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