Monday, March 28, 2016

Misconception about "Red Tide" and mussels

Let me start my blog today with the following quote from Wikipedia on the subject of red tide.

"The occurrence of red tides in some locations appears to be entirely natural (algal blooms are a seasonal occurrence resulting from coastal upwelling, a natural result of the movement of certain ocean currents)[13][14] while in others they appear to be a result of increased nutrient loading from human activities.[15] The growth of marine phytoplankton is generally limited by the availability of nitrates and phosphates, which can be abundant in agricultural run-off as well as coastal upwelling zones. Coastal water pollution produced by humans and systematic increase in sea water temperature have also been implicated as contributing factors in red tides."   

The article goes on to state that the term “algal bloom” is more accurate as sometimes this phenomena is neither 'red' nor has anything to do with tides per se.

What does this have to do with the Philippine Cold Chain Project? 

As we examine where the links in various production systems for high value perishable foods are most vulnerable, it is necessary to find solutions to fix the vulnerabilities.  In the case of caged lobster production, one vulnerability is the source of fry and another is the source of feeds for lobsters.

Lobsters like to eat other things that grow in the ocean and if that food is overharvested, it can cause a detrimental environmental effect and also cause lobster farmers to go out of business!  So lobster raisers must look for ways to provide a sustainable supply of by-catch or trash fish or shell fish or sea urchins for the lobsters being raised.  One favorite food of lobsters are shellfish.  Things like oysters or green mussels provide great nutrition for lobsters being raised in cages.  So PCCP has asked the question…where are green mussels grown in the Philippines and why are not more people growing green mussels (tahong)?  Green mussels are relished by people too and their orange meat color provides excellent pigmentation and protein for lobsters and people.  Tahong are filter feeders that get all of their nutrition from plankton in the water.  They can grow in areas with high salt content in the water and really do the best in murky waters.  The mature males and females release their respective sperm and eggs into the water and when fertilization occurs, if the water conditions are right, then the baby mussels or spat then cluster and grow, often on ropes or bamboo poles provided by people and are harvested at about six months old.

 Recently, I took some time to visit a mussel producing area in Samar.  With me were PCCP fisheries specialist Toto Nobillos and Fred Yap of Tateh Feeds.  We visited Samar State University - Mussel Raising Project in Catbalogan, and then made a stop at Jiabong just south of Catbalogan where there is a bay full of bamboo poles on which tahong is being cultured.  These filter feeding marvels, once they settle in to their spot on the rope or pole, grow and eat for free.  No feeding is required.  The mussel farmer just has to provide the right conditions and wait for harvest.  Mussels use small threads to attach themselves to the place where they remain and feed.  These are called byssal threads and must be cut with a pair of scissors when harvesting to avoid any damage to the mussel.  It is also better to use coconut fiber rope or coir for the mussels to attach on since provision of nice synthetic rope may invite rope theft. If cultured correctly, mussels can be a valuable ecological and income-generating addition to a multi-species fish farm or mariculture park.  They clean the ocean and eat for free and provide nutritious,  tasty food for people and lobsters.

We proceeded to Jaibong and interviewed some mussel farmers who were just selling their catch next to the highway.  These farmers were selling big 30-kilo sacks at 80 pesos per sack.  The sale point was right next to the main highway so truckers and busses would stop and load up this live, precious cargo.  Business is good since the retail price for tahong in Davao City is 50 pesos a kilo in the market!!  The nearby bay was filled with bamboo poles used for mussel raising. 

With the mussels we got from the school project and those that we purchased from the local farmers in Jaibong, we loaded up our pickup truck with supplies to set up a test area for mussel-raising with lobster raisers near Surigao City.

So the initial plan was to take this first batch and see how they would thrive at a local mariculture park.  Since Bureau of Fisheries (BFAR) has oversight of this park, of course we asked for permission before introduction of the tahong.  The site we had in mind was ideal…murky water and close to where lobsters are raised so project members could keep an eye on the mussels. 

However much to our SURPRISE, the key official of the BFAR informed us that we could not introduce tahong in this area because….(get ready)….Tahong are the cause of RED TIDE!!!! (my emphasis). 

Now a normal, uneducated person may have some misconception that since people get sick when eating mussels when there is a severe algal bloom, that in fact mussels might be implicated in the causation.  However, this could not be further from the truth.  Mussels clean dirty water and when they filter and eat something bad in the water through no fault of their own,  this bad substance can infect the mussel and cause whoever eats the mussel to get sick. This is why mussels are banned for harvest when there is a red tide.   It is, however, incredible when someone who is supposed to be educated and a source of information about fish and aquaculture would base a decision on information that is completely false.  This misconception cannot even be called an old wives tale…as old wives would know better!

At the end of the day, the test culture had to be set up in another area outside of the mariculture park. After a couple of weeks on their new ropes the Tahong appear to be growing well. We will continue to look for ways to make this project thrive and hope that we can produce enough mussels locally to provide sacks of food for lobsters and for people as well.