How to Cut Up a Slaughtered Pig

How to Cut Up a Slaughtered Pig
 
Last December 31st, a family friend gifted us with a whole freshly slaughtered fattening pig from her pig farm – but already scalded, hair removed, cleaned, and all blood and entrails taken out. They delivered it to our Manila home.

It was a terrific gift but how do we store it to keep it fresh? We have a regular fridge with the freezer section all stocked up. Also a partially filled upright freezer with some space left. But how can we store a 40 to 50 kilo pig in there? We also have an old fridge that has a large freezer section but it had been retired so we can save on electricity bill. That old fridge gave us an idea. Why not use it temporarily? Yes, why not?

So we had no choice but to cut up the whole pig carcass into pieces! My wife suggested we hire a butcher. But we thought it would be better if we cut it up ourselves. It would be a good learning experience. 

So we quickly browsed through some DIY pig butchering videos on the web.

Later, armed only with some rough notes in my note pad and some nice quick-fix video lessons, we took out the following tools and materials, and started work.

· An outdoor round table, which we set up in the kitchen

· Several pieces of freshly cut banana leaves, which we laid on the table

· A couple of our old chopping boards from a sampaloc tree

· A common hacksaw – in absence of a meat/bone saw

· Cleaver

· Boning knife

· Long knife

· Sharpening rod

· Freezer bags and plastic storage bags

· Masking tape and ball pen

· A large plastic basin

· A temporarily reactivated fridge

Being novices, we considered it an adventure more than a task. But we had to be extra careful not to cut ourselves. 

Cut Head

First the pig’s head. we cut the head from the body just behind the ears. We put the entire head piece in the plastic basin.

A pig's head

Cut the Carcass into Two Halves

Next step was to cut the carcass lengthwise into two symmetrical halves. The idea was to cut across from the neck down to the rump. We needed the hacksaw to cut through the backbone (Note: made sure that the frame and blade were washed and scrubbed clean). As a result, we got two identical sides of the carcass - each with the shoulder section (with front leg), the midsection, and the back leg (ham) section. We took out one side and placed it aside temporarily in the plastic basin.

 

Pig carcass cut into two symmetrical halves

Cut Each Side into 3 Major Sections

With one side of the carcass laid out on the table, We took out the hacksaw, one long knife, and one boning knife. We first cut the side into 3 major sections: back leg, shoulder, and midsection.

1. Back Leg

· Marked the cut line by locating the aitch bone (it’s the rump bone located in the pelvis).

· Measured three fingers off the bone toward the midsection.

· Cut the body crosswise using the cut line as guide. Used a long knife to cut through the meaty part of carcass. Then used a hacksaw to cut through the backbone.

· Set aside the entire back leg (ham) section.

2. Shoulder

· Checked out the ribs.

· Counted to the 5th rib.

· Marked the cut line between the 5th and 6th rib.

· Used a long knife to cut through the carcass crosswise using the cut line as guide.

· Used the hacksaw to cut through the backbone and ribs.

· Set aside the entire shoulder section.

3. Midsection – this is the section that remained after we cut off the back leg section and shoulder section. It consists of two subsections: loin and belly.

Repeated Steps 1, 2, and 3 above to cut off the other side into its 3 major sections (also known as primal cuts).

Store the Major Cuts in the Freezer

Luckily our idle fridge with a large freezer section was still working after we plugged it in. So we packed the seven major cut parts each in a large plastic bag and put them temporarily in the freezer. These were the:

· Head

· 2 shoulder sections

· 2 midsections

· 2 back leg (ham) sections

Cut Up Each Major Section into Primals and/or Sub-primals

1. Head – We decided keep the entire pig head intact in the freezer and not process it. I plan to take the entire head to our fish farm in Binmaley, Pangasinan where my farm cook will do the following:

· Clean it up thoroughly and remove any hair, remnants of dirt from ears, etc.

· Debone the head from the chin, around the jaw up to the rest of the head until all the meat is free (cheeks, ears, snout)

· Split the skull with a hacksaw into two to extract the brains

· Keep the skull pieces for boiling/roasting for stock
 
We planned to use the head meat for making sizzling “sisig” or “dinakdakan” (Pangasinan and Ilocano version of "sisig”) (to be covered by a future blogpost later). It’s a popular local dish which involves boiling pig head parts, grilling, hand chopping, mixing with chopped onions, chilis, calamansi (fruit of native Philippine citrus tree) and even coconut cream and cooking the mix in a hot plate. It’s delicious!

2. Shoulder Section A – We took out one of the two shoulder sections from the fridge and laid it on the round table to cut it up further into sub-primals. Here’s what we did:

· Cut off the trotter (foot part of the front leg) at the joint between the forefoot and lower limb (much like our wrist joint). Commonly called the pig’s foot.

· Cut off the hock (lower part of front leg) a bit above the elbow joint between the upper arm bone and lower arm bones.

· Removed the rib bones, part of spine, and feather bones.

· Cut off the so-called Boston butt ("paypay" or also the more general term "kasim" in Tagalog) lengthwise to remove the meat part from the shoulder blade.

· Cut remaining shoulder meat lengthwise from arm bone toward the shoulder blade. Cut off what we called “Picnic 1” (also called "kasim" in Tagalog) from the left part.

· Cut off “Picnic 2” from the top portion of the right part.

· From the remaining meat portion, removed the shoulder blade bone and also the upper leg bone (humerus).

· What remained is what we called “Picnic 3” after the bones were removed.

· Packed the sub-primals of the Shoulder Section A each in a plastic bag.

· Labeled them using masking tape: trotter, hock, Boston butt, Picnic 1, Picnic 2, Picnic 3, and shoulder blade bone and upper foreleg bone.

· Stored the above packed cuts in our upright freezer.

3. Shoulder Section B

· Took out the second shoulder section from the fridge and did same steps as in #2 above.

4. Midsection A – Took out one of the two midsections and laid it on the cutting table. Did the following steps:

· Separated the loin from the belly. Cut the midsection lengthwise following the curve of the spine (so belly is wider than the loin). Use a long knife and also hacksaw to cut through the ribs.

· Removed the ribs off the belly. Set aside.

· Cut using long knife the belly almost in equal parts crosswise – to get two parts – bacon belly (the flatter more level part) and fresh belly (the lumpier uneven part).

· Cut the loin crosswise into two almost equal parts (at about the last rib) to get two subprimals: loin roast part and porterhouse chop part (which still contain the tenderloin).

· Packed the resulting sub-primals of the Midsection each in a plastic bag.

· Labeled them using masking tape: ribs, bacon belly, fresh belly, loin roast part, and porterhouse chop part.

· Stored the above packed cuts in our upright freezer.

5. Midsection B – same steps as in #4 above.

6. Back Leg Section A – This is one of two back leg (ham) sections still in our old fridge. So, we took out one and laid it on the cutting table. We went on to cut it up into its sub-primals as follows:

· Cut off the trotter (lower part of back leg) at the joint between the forefoot and lower limb.

· Cut off the hock (upper part of back leg) a bit above the elbow joint between the upper arm bone and lower arm bones.

· Removed the aitch bone (rump bone located in the pelvis) and detached it from the socket of the upper back leg bone.

· Using the socket and the entire leg bone as guide, peeled off the top part of the meat (so called top round).

· Cut off the part of the meat at the left side of the leg bone (I called this Ham Roast 1).

· Peeled off the portion at the right side of the leg bone (called it Ham Roast 2) by slicing with a knife along the length of the bone.

· What remained was the upper back leg bone.

· Sliced Ham Roast 2 some more into two smaller parts lengthwise and labeled them Ham Roast 2a and Ham Roast 2b.

· Packed the resulting sub-primals of the Back Leg Section each in a plastic bag.

· Labeled them using masking tape: trotter, hock, top round, Ham Roast 1, Ham Roast 2a, Ham Roast 2b, and aitch bone and upper back leg bone.

· Stored the above packed cuts in our upright freezer.

7. Back Leg Section B - did the same steps as in #6 above with some slight changes to correct the careless mistakes we made in the cutting of the trotter and hock of the back leg.

In Back Leg Section A, we made a mistake and cut above instead of at the joint of the trotter (much like our ankle) and also erred in cutting the hock (we cut just below the elbow joint instead of at the elbow or slightly above elbow).

When we cut off the trotter and hock for Section B, we got it right this time.

So there you have it guys! We succeeded in butchering our gift pig into its primal and sub-primal cuts and had them all stored in our upright freezer to preserve their freshness.

Thanks to the 3 part series “How to Butcher a Pig” featuring Camas Davis of Portland Meat Collective – these You Tube videos were our main reference guides in doing what we did fairly decently despite being novices.

Later on, we will take out each sub-primal cut, thaw it and fabricate it into smaller cuts for roasts, steaks, chops, cutlets, stews, barbecues, ground pork, and others depending on what meat part my wife needs for a specific dish.

Sub-primal (picnic from the pig's shoulder section) cut into smaller pieces (later turned into ground pork)


For a complete list of Fish Pond Buddy blog posts on fish farm-related topics, please click the Index page.

Uses of Coconut Trees in Our Bangus (Milkfish) Farm

Uses of Coconut Trees in Our Bangus (Milkfish) Farm

The coconut tree is known in the Philippines as the “tree of life”. Raised in the city, I thought it was just a cliché, and took it for granted. After a few years staying at our fish farm next to coconut trees, I came to appreciate the real value of the so-called "tree of life".

Coconut trees along the dikes of my bangus ponds; their roots prevent soil erosion

Today, our bangus farm is one of the few places in our locality that still has lots of coconut trees planted to it. The trees are planted along the earth dikes surrounding the six ponds in my 2.3 hectare fish farm.

Eight years ago, when I took over, only about 40 old coconut trees remained. A number soon fell victim to attacks of the notorious rhinoceros beetles and later died. We sought help from the Philippine Coconut Authority (PCA) office in Sta. Barbara, Pangasinan. They suggested the use of the pesticide “Karate” to be sprayed at the bottom of the crown or top of the trunk.

Thanks to PCA, we succeeded in halting the infestation and also started replacing the dead trees. Seedlings were available at PCA at P20 per piece then. Every start of the rainy season, we bought 40 to 50 pieces of seedlings and planted them along the dikes.

How the Coconut Trees and their Various Parts are Used in Our Farm

A. For Dike Strengthening – we plant coconut trees along the fish pond dikes; their well-developed roots strengthen the dikes and prevent soil erosion.

B. For Food and Cooking – first of all we classify the coconut fruits in our fish farm into five types:

· Young green nut ("buko" in Tagalog, “malangwer” in Pangasinense) with its soft meat to be eaten as is, or for salad, or mixed in "buko" juice.

 Various types of nuts (brown one at the left, those with wrinkled skin at bottom are the mature green nuts)

· Mature green nut ("magulang", “mataken” in Pangasinense) with its harder meat to be made into sweetened coconut delicacies such as “bucayo”, “bucarillo”, or “pastillas”.

· Brown mature nut ("niyog") – whose meat is used for making coconut milk ("gata").

· Rotten coconut ("kukot") – nut which has been punctured by bats or rats up the tree; it rots and falls to the ground or in the pond. Still useful as firewood material.

· Very young and green nut ("butayong") – coconut fruit that still has no meat, but with coconut water and with tender shell that is edible. Normally not picked and instead allowed to mature some more, but may have been accidentally snagged and felled by a coconut picker.

A very young green nut, with water, no meat, but with edible shell

 
1. Coconut water – my personal favorite, is a natural, healthy, refreshing drink that is known to be good for the kidney. Often I ask my workers to pick some fruits from the tree just to quench my thirst. It's a safe energy drink. See my separate post on how to pick green coconuts from high up a tree without climbing it (to be posted later).

Cutting open a young green nut

2. Coconut meat – can be eaten fresh once the fruit (the young green nut) is cracked open. With a coconut grater, my workers extract the soft meat as ingredient to make fruit salad. They also use the grated meat of a mature nut to make "bucayo" (a local sweetened grated coconut meat). 

Cooked sweetened grated coconut meat ("bucayo")

 
3. Coconut milk – obtained by pressing scraped coconut meat of a mature (brown not green nut) to extract the white milk-like liquid ("gata"). Main everyday use of the milk among my workers is for cooking “ginataang gulay” (vegetables such as string beans cooked in coconut milk), or "ginataang isda" (fish such as tilapia cooked in coconut milk).

Coconut meat being extracted from a mature brown nut using a metal scraper

 
4. Coconut dip and jam – We also cook coconut milk either with brown sugar or molasses or caked cane sugar to make "katiba" a dipping sauce for the popular Philippine glutinous rice delicacy ("suman"). Without dipping sauce, "suman" tastes bland. With the sauce, it becomes mouth-watering.

On the other hand, coco jam (called "matamis na bao") is similar to "katiba" but is cooked until it becomes thick.

5. Coconut milk curd ("latik") – Our farm house cook make this by cooking about two (2) cups of coconut milk in a wok. They are the golden brown solids that you see being formed together with the natural oil that comes out. We use this delicious and tasty curd as toppings for Filipino desserts such as “biko” or “kalamay” (which is made from glutinous rice or "malagkit", brown sugar, and coconut milk). These are desserts that the locals are fond of making for special occasions or in bulk to be sold in the town market.

6. Coconut oil – the oil that comes out from coconut milk cooked in a wok is usually used by my workers for "hilot" (traditional way of healing among rural folks using massage therapy and herbal medication). 

For "hilot", the oil is mixed with crushed ginger and kerosene. Click this for my related post on "Traditional Healing in the Fish Farm" where "hilot" is discussed.

As for the common cooking oil, well, we don’t make this for sure. But we all use it in the farm for frying or sauteing. They’re commercially made from dried coconut meat or kernel from which oil is extracted – also known as "copra". These cooking oil are readily available at the nearby "sari-sari" store (local grocer), or public market or supermarket in the town proper.

The extra virgin coconut oil is entirely different and used for salads or consumed directly as dietary supplement. I've tried it myself. Extra virgin coconut oil is well known for its many health benefits.

7. Coconut sap – although we have not tried this in our farm, it’s a common practice in coconut producing regions of the Philippines to extract the sap through incision of the bud to make the popular "tuba" or coconut toddy. The tip of the unopened coconut bud is cut and the juice allowed to trickle into bamboo containers (as much as a gallon daily). When distilled, tuba produces "lambanog" or the local coconut vodka. Coconut sap can also be used to produce coconut vinegar.

8. Coconut bud at the topmost part of the coconut trunk – we use this part to extract "ubod" (palm heart or palm cabbage) as ingredient of the popular Filipino vegetable "lumpia ubod" or spring rolls. "Ubod" refers to the vegetable part of the inner core or growing bud of the coconut tree. It is found only at the topmost part of the trunk. This happened only once in our bangus farm when one of our old coconut trees was felled by a strong typhoon.

C. For House, Garden Use

1. Coconut shell – we use this as charcoal or firewood for grilling/cooking.

Dehusked shell still with meat inside and half shell without meat (already scraped off)

 
2. Coconut husk (dried brown-colored - consists of the thin hard outer skin, the fiber portion inside, and the hard inner shell)

Coconut husks

 
· Half of coconut husk - used as a vase for our hanging plants (see photo below). Smaller pieces of husks (see above photo) can also be used as vase when parts are sewn together using nylon thread. Then GI wires are attached for hanging.

In addition to its use as plant vase, the half of the coconut husk (still with shell) is used as floor scrub ("bunot") when polishing either cement or bamboo floors. As substitute for floor wax, we use green banana leaves (of the "balayang" or "saba" variety). It's a natural floor wax. Try it.

Half of coconut husk used as vase

· Coconut husk cubes - used for potting medium. The outer skin and attached fiber are chopped into small cubes and mixed with garden soil, compost, etc. as potting medium for ornamental plants.

· Coco peat – the residual dust, coco husk particles, and shorter fibers we gather together and put in a sack. This is also used as good potting medium for our various plants.

3. Coco husk fiber – is the fibrous material between the hard internal layer (shell) and the thin hard outer coat or skin.

· Chopped fiber - we pull them out of the husk, chop them into small pieces using machete, and the result is coco husk fiber bits used as potting medium for our ornamental plants.

· Unchopped coco fiber – by itself we use this as (a) bottom layer for our pots and vases for improved drainage and also prevent washing out of garden soil (b) as planting layer for hanging ferns when latter are mounted on fern chips (c) as planting medium for big ferns that are grown in large vases or pots.

Unchopped coconut fiber

 
4. Coconut trunk

· Coco lumber from trunk - we make use of trunks of dying trees by ripsawing them into wood pieces that go into building of sheds, plant stands, and for other building purposes in the farm.

· Bottom part (base) of trunk – we use this as decorative stand for our potted plants. Round holes are carved out on top of the trunk for our plant vases/pots, thereby serving as decorative stand in the farm garden.

Coconut tree base (standing upside-down) serves as decorative plant stand; holes for holding pots were carved out at the top

 
· Short pieces of the trunk – are used as elevated mounting for potted plants.

Section of coconut tree trunk used as elevated mounting for potted plant (left); also used as mounting for water plant in terra cotta vase (right)

 
· Bark trimmings - bark portion of trunk is sawed off to expose the inner lumber part.

When cut thick, these bark trimmings are used as shelves for plant stands. Long planks are used as sidings (anchored by bamboo stakes) in the repair or land-filling of earth dikes. When cut into foot long sections, they can be used as mounting medium for hanging plants (such as orchids and ferns). Recently, we used some bark trimmings as sidings for the pen we built for our native pigs.

Coconut bark trimmings

 
· Coco lumber sawing dust – the dust residue from sawing of various pieces of coconut lumber derived from the trunk we also gather and put in sacks and stored for a few months. Afterwards, we mix them with compost and garden soil as potting medium.

5. Coconut leaves and leaflets – we use this for:

· Leaf midrib as firewood – we normally use the dry ones which have fallen off trees along the dikes. The thick middle part (midrib) of the leaf is set aside for firewood after removing the leaflets

Leaflets being removed from the thick midrib of a coconut leaf

 
· Leaflet midrib as broomstick – long leaflets of dry coconut leaves are set aside. Then the hard middle spines (leaflet midribs) are made into "walis tingting" (broomstick). The shorter leaflets are used as kindling material.

A couple of broomsticks made from the midribs of coconut leaflets

Choosing long leaflets whose midribs are used for making a broomstick

 
· Wrapper - the young yellow leaflets of the coconut tree are the ones used as wrapper for the popular glutinous rice delicacy ("suman"). Also wrapper for "patupat", another Pangasinan delicacy similar to "suman" but boiled in molasses.

· Exterior or interior house wall - several pieces of coconut leaves (complete with its leaflets and midrib) are cut, secured by bamboo, and woven together to make walls for houses. See separate post on how to make a coconut leaf wall (to be posted later).

6. Coconut flower stalk and sheath - we use these as follows: 

Clockwise from bottom: flower stalk (fingerlike), sheath (cover), two short pieces of coconut trunk used as elevated plant stand, several pieces of long leaflets to be used for broomstick, and (rightmost) a couple of midribs

 
· Stalk - ("gamet") dried brown ones are split into two and used as firewood. By itself, can be used as a substitute broomstick.

· Sheath – ("palay palay") dried brown ones are also used as firewood.

The uses of the various parts of the coconut tree as described above are based on actual and personal experiences in our farm. They are simple, day-to-day applications and not meant to be exhaustive.

The Philippine Coconut Authority (Market Development Department) in Diliman, Quezon City, provides complete and expert materials and technical information on coconut products. They have brochures and product descriptions on coconut flour, desiccated coconut, coconut sap sugar, copra meal, coconut shell powder, coconut shell charcoal, coconut shell, coir, coir dust/coco peat, coconut biodiesel, coconut milk, activated carbon, coconut oil, virgin coconut oil, "nata de coco" (coconut gel), coconut water, and others that I may have missed.

No wonder, the humble coconut tree is indeed the so-called "tree of life".

For a complete list of Fish Pond Buddy blog posts on fish farm-related topics, please click the Index page.

Monitoring A Bangus (Milkfish) Pond

Monitoring A Bangus (Milkfish) Pond

Monitoring "Tangok" (Oxygen Starvation-Related Fish Stress or Kill)

There were ominous signs.

In the week before emergency harvest, we saw signs of fish stress in bangus in the grow-out pond. It was the middle of the dry season (December to May) and there was hardly any rain (7 consecutive weeks of dry weather). Water levels were dropping. And the pond kept getting saltier due to evaporation.

Unfortunately, our ponds (being closed system) were not visited by tidal waters which come and go. We’ve already let in the seawater and were just relying on rainwater the rest of the year.

From my personal research, we learned that the saltier the water and the warmer it is, the less oxygen (more accurately, dissolved oxygen or DO) it can hold.  

We had about 4,500 pieces of bangus for grow out in our Main Pond (about .6 hectares). We noticed, to our dismay, that the pond contained quite a number of tilapia too (which accidentally flowed in due to the past floods). The tilapia competed not only for DO, but also for nutrients and pond space, thereby increasing pond density. Pond color was brownish green.

My farm overseer had been observing clusters of bangus swimming at the water surface, gulping air during the early morning hours for about a week prior to my visit. At the feeding area, bangus seemed to be feeding less and were a bit sluggish.  

We were aware that lethal oxygen depletions begin with similar signs. The ones we observed, however, were not alarming at the time. Fish dived back to deeper waters as soon as the early morning sun shone and they stayed underwater. The clustering of bangus was also not as extensive.

Bangus starved of oxygen and swimming near the surface in clusters (phenomenon called "tangok" in Pangasinense); if pond condition worsens, could lead to fish kill
  
We therefore started tracking the water quality of our pond, especially the DO content. Too bad, we had no DO monitoring device (we just rely on occasional visits of the technician from the feed supplier) and couldn't measure if the DO was within acceptable range (i.e. above 3 ppm). So we had to depend on visual checks at the early morning hours – 5 a.m. thereabouts.

On the following days, pond conditions started to worsen. Clusters of bangus swimming near the surface were now seen in several parts of the pond (before, we saw only a few, isolated clusters). The fish tended to ignore human and predatory bird presence and continued gulping air at the surface. The gulping fish stayed at the surface longer even as the sun rose.  

We also noticed the onset of milky colored streaks at the water edge and below. We thought we may have a fish kill in our hands pretty soon.
 
After four days, we decided to take action. Our plan was to do an emergency harvest and move all fish out of the Main pond. We intended to grow my bangus to the marketable size of 250 to 300 grams per piece but then had no choice. 

It was either we harvest and sell slightly undersized bangus or soon find most of them dead in the water and sell at almost give-away prices.

Nature of “tangok” and its main causes

“Tangok” (fish starved of dissolved oxygen and swimming to the surface, leading to stress/fish kill) to me, is one of the biggest threats in bangus farming. When "tangok" becomes severe and bangus start dying in large numbers due to increasingly poor pond water condition, there is no choice but to do emergency harvest to cut losses.

As a result, bangus need to be taken out undersized, or worse - under very severe conditions - dead. This means less quantity, less number of kilos, lower total sales, and lower profit for the cropping season. Under the worst scenario, a pond owner may sustain massive losses due to large-scale fish kill.

What are the causes of severe "tangok" and eventual fish kill?

Based on our experience, research, inputs from our technician, and interviews with neighbors, it’s a combination of things going wrong at the same time. As a result, DO in the pond gets depleted because it is being consumed much faster than oxygen is being added to or absorbed in the pond.

What are the factors or conditions that contribute to "tangok" in bangus farms as we've experienced it?

1. Weather

· Hot weather during dry months (especially February to April or May) – pond water has less DO because warm water is less able to hold DO compared to cool water.

· Cloudy days – sunlight is blocked thus stifling the oxygen-making ability of plant organisms in the pond.

· Calm, still, windless days – oxygen is believed to be added to the pond surface through the action of wind. When it’s windy, pond is ok, no "tangok". In absence of wind, risk of "tangok" is higher. 

 · Stormy days – one of the effects of tropical typhoons is the strong winds which defoliate trees along the edge of ponds where leaves are blown off and dumped into the pond. The effect can bring about "tangok" about a week after as a result of the rotting of organic leaves at the bottom of the pond (see Item 6 below). 
 
2. Season

· El Nino – During the onset of the El Nino, temperature is extraordinarily high and pond water levels go down. El Nino, according to our Philippine weather experts, refers to a seasonal warming of the Pacific Ocean. It upsets normal weather patterns, (giving rise to short rainy season or causing droughts especially in Northern Philippines, including Pangasinan). It’s our experience that during El Nino, DO level in pond waters dip dangerously. In fact we suffered large mortality of fingerlings in the past, mainly due to lack of experience with El Nino when we were just starting our bangus farm.

· Dry Months – period from December to May are dry months when no rain is expected. March, April, and May are the equivalent of summer in the Philippines when pond water levels in Class C ponds go down and water temperature rises (though not as severe as during El Nino). Class A and B ponds continue to have water from river sources due to the action of tides.

3. Disturbance of pond water - natural and man-made

· We also observed "tangok" in the pond during certain weather events (e.g., short sudden thunderstorm after clear sunny days).

According to experts, the upper layer of water cools down and sinks. While the bottom layer of water rises to the surface. The result is the unwanted mixing of layers of water. The bottom layer is said to be normally oxygen-depleted, stagnant, and decaying. When this layer rises, the oxygen consumption of the bottom materials increases in the process; bangus is deprived of DO, thus causing “tangok”.

· Disturbance of water layers also occur when poachers wade into the pond to illegally catch bangus using gill nets. If this happens, especially when pond bottom is “hot”, silt level is thick, and a foul smell is detected, then the unsettling of water can trigger “tangok”.

4. Overstocking of fish due to unexpected presence of competitor fish (usually tilapia)

· A low DO level is made worse by overstocking of fish beyond the optimum carrying capacity of the pond. But how did this happen when the stocking quantity of bangus was carefully followed (i.e. 8,000 -10,000 pieces per hectare)?

a) unexpected presence of tilapia in large numbers. Maybe the result of poor pest eradication during pond preparation - not all the small tilapia fish and tilapia eggs may have been killed.

b) incursion of water from an adjacent fresh water pond that has tilapia and/or gourami fish in it, especially during rainy season. This happens when there are low lying dikes that are flood prone.

c) also there may be tunnels or burrows in the dike caused by burrowing rats through which tilapia or gourami can enter. Or hollow pockets in the dike due to rotting roots of dead tree that used to grow in the dike.

Being fast breeders, tilapia quickly populate the pond and compete with the bangus for feeds and dissolved oxygen.

5. Thick growth of algae and/or rooted submerged aquatic plants (locally called "tariktik")

· They use up DO and give out carbon dioxide at night. Although they are a source of DO during photosynthesis, these plants do consume a lot of DO during the so-called respiration phase when they become too dense or too thick. During cloudy days, when sunlight is blocked, less oxygen is produced for the fish to consume.

6. Piling up of rotting organic materials and wastes in pond bottom.

· The pond may have substantial organic stuff that settled at the bottom and later decayed or decomposed, thus starving the pond bottom of oxygen. Examples are:

a. Submerged aquatic plants rooted in the bottom soil ("tariktik") that started to sink and decay.

b. Pond algae that earlier proliferated (pond is colored green) but later died, sank, and rotted at the bottom (pond color turned grey, brown, or became clear).

c. Excessive organic materials such as chicken manure, which some pond operators apply in addition to commercial feeds. When this organic matter decomposes through the action of anaerobic bacteria, according to our technician, it produces toxic gas like ammonia and hydrogen sulfide, thus making the condition of the pond much worse. When this happens, you can detect the foul smell that the pond emits. 
Much like the smell of rotten chicken eggs.

Sacks of chicken manure - normally used during pond preparation as organic fertilizer

d. Tree leaves, coconut fronds, rotten coconut husks, dike grass cuttings (we have lots of these, they're all around our ponds, not to mention mango and other trees). These can fall into the ponds through natural defoliation of old leaves or blown away and dumped into the ponds by strong winds that come with a tropical typhoon.

Taking out coconut fronds and leaves from ponds and piling them up for drying and  cutting into firewood pieces

 
e. Aquatic droppings, silt, and other residues settling on the pond bottom.

What to Do

1. Invest in a portable dissolved oxygen meter to be able to accurately measure the DO content of the pond and to provide enough time for corrective action. Monitor DO levels daily.

2. In the absence of a pond aerator, use a portable water pump to suck in water from the bottom and discharge it in air. Harmful gases are released and oxygen from the atmosphere is expected to be absorbed.

3. Take out the excessive pond weeds ("tariktik") from the pond to prevent its decay at the bottom (we do this using a bamboo raft on which pond weeds are stacked). Pile up the "tariktik" along the dikes of the pond and let it dry out and decay outside the pond. Later on, this layer of decayed "tariktik" can be returned to the pond as organic feeds for the bangus.

4. Take out other rotting debris from the bottom of the pond BEFORE they rot. Examples are coconut leaves, rotting coconut fruits, tree leaves and branches, etc.

5. In case of mild "tangok", temporarily stop feeding for the day since the bangus are stressed out and don’t have normal appetite to eat. Commercial floater feeds applied to the pond will just eventually sink at the bottom and rot, adding to the depleted DO condition of the water. If DO is at the stress level (below 3 ppm), postpone feeding.

6. In the case of excessive feeding, such as use of both commercial feeds and chicken manure, discontinue the application of chicken manure. Most bangus growers (especially in Class C ponds like ours) stop feeding commercial feeds altogether, and instead shift to the use of "lumut" (filamentous grass-green algae) or even stale bread as feeds.

Tossing "lumut" into the pond as alternative feeds

 7. When foul smell is detected in the pond, apply 16-20-0 (mono-ammonium phosphate) at a rate of 50 k per hectare to cool the heat at the pond bottom and let out toxic gases into the air.

8. Do partial harvest of bangus to reduce the pond’s fish population. During the harvest, take out as much tilapia as possible, which compete with the bangus for both feeds and dissolved oxygen. Assign one or two of your ponds exclusively for tilapia growing. During partial harvesting of your bangus ponds, when you take out young tilapia, transfer them to such designated ponds.

9. In the case of Class A ponds, allow the change of pond water by draining out a third of the existing pond water during low tide and replenishing it each day for two to three days during high tide. This dilutes the decomposition of unused food and other organic matters. It also lets in water with adequate oxygen levels into the pond. 

Caution should be observed, however, to make sure that the prevailing water condition in the river is of acceptable quality. When it’s not high tide you need to use water pump to pump in replacement water.

10. Review effectiveness of pond preparation steps taken. See to it that pest eradication is done properly, using correct type and quantity of organic and/or inorganic pesticides, to completely eliminate competitor fish such as tilapia and predator fish such as dalag. Check surrounding dikes carefully for hidden tunnels or burrows through which tilapia from adjoining tilapia ponds can enter. Do land fill work for dikes which are low-lying and prone to incursion of flood waters during heavy rains.

11. Be on the look out for the onset of the El Nino several months before it happens. This will allow you to plan and program your bangus growing for the next several months. And also to develop contingency plans. The idea is to ensure that when El Nino does come and when pond water levels drastically drop as a result of the abnormally hot weather, then the ponds would have been emptied of bangus to avoid high mortality or fish kills. 

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