By: Ph.D. Stephen G. Newman*
The tonnage of shrimp produced by aquaculture is at an all high with no end apparently in sight. Have we achieved sustainability or is this another peak that will end abruptly followed by a significant drop in production only to rebound once more?
The word sustainable has become a commonly used and abused term, much as the terms “green”, “eco”, “organic”. What exactly does sustainability mean and how would this be applied to shrimp farming? There are several components to true sustainability.
These are not intended to be all inclusive but are focused on the highlights.
✓ Production is readily kept at steady levels and when it is increasing it is done in a manner that ensures that this growth rate can persist.
✓ There is no damage to the environment from the process. Resources must be used in a manner that ensures that one’s descendants would be able to operate in the same manner with similar outcomes.
✓ Ideally the cycle is closed with no to little waste. Offal is used as fertilizer or as a raw material for feed ingredients (where permissible). Waste streams are used in some manner that is ecologically neutral at best (i.e. no negative impact on the environment). Feed is made from recycled ingredients.
✓ The impact of disease is reduced to the point where it does not cause economically significant losses and when it does occur it is contained and cannot spread globally.
✓ It must be profitable and with no exploitation of labor.
Getting at exact production numbers is not straight forward as these rely on what the government is reporting which in turn relies on the methods used to determine the numbers as well as in some cases a bit of creative number crunching.
“When there are high levels of domestic consumption this can skew the numbers somewhat. It is easier to track exports. Thus, there are a range of figures that are being reported.”
Two species make up most of the production with one, Penaeus vannamei, the white shrimp being a bit under 80% or more of the total. P. monodon, the tiger shrimp makes a little under 20% or so. A half dozen other species make up the remainder.
Table 1 show the reported figures for the main producers for the period 2020 to 2021.
Most production still takes place in SE Asia and even though Ecuador is doing very well with no sign of slowing down, the super high density production paradigms that many feel will eventually become the norm in most areas in SE Asia are ultimately more profitable and less costly in the long run. But are they sustainable?
The production paradigm in Ecuador has been pretty much the same basic model, stocking at low densities in large ponds, 8 to 10 ha average, since its inception.
“The last few years have seen a change in that stocking densities have increased in some instances, doubled, and even tripled; aerators are in much wider use as are automatic feeders that ensure less wasted feed.”
Greater attention is being paid to the environment by the use of in-situ bioremediation of organic matter. Genetically improved animals that grow to marketable sizes quickly are part of this successful formula as well.
In SE Asia only a few decades ago the common model was dirt lined ponds with some aeration and stocking at moderate densities.
As these systems have failed repeatedly over the years, they have evolved in a relatively short period of time to lined ponds, small, frequently under 5,000 m2 with sumps that collect much of the organic matter.
“Super high density, very small ponds are common. In some cases, tanks have replaced small ponds.”
Bioremediation is in use as are genetically improved animals. It is safe to say that global totals are at least 5 million MTs and could range close to twice this much.
If one looks at these countries individually, sustainable shrimp farming, as defined above, is not here yet.
Production is increasing and in general is volatile historically. Supply and demand are elements of this but so are controllable factors.
Diseases are the costliest single factor affecting profitability and consistent growth and thus sustainability.
“Producing large numbers of animals in aquatic ecosystems where stressors are common, and pathogens may abound due to the open nature of the system ensures animal health challenges.”
Recent technological advances suggest that there are large numbers of uncharacterized invertebrate viruses in these environments. There are many as of yet other non-characterized potential pathogens waiting for the right environment to march through weakened populations.
The single largest source of potential pathogens is in post larval shrimp that have not been produced under biosecure conditions. This is not to say that the presence of vectors, cross contamination and fomites do not contribute as well.
“Specific pathogen free (SPF) shrimp were developed as a response to this threat many years ago with
There are many holes in what many shrimp hatcheries think are absolute biosecure operations.
Nucleus breeding centers are becoming more common. Nonetheless, the manner in which some broodstock producers work lends itself towards problems. Among these and discussed previously are the use of nonbiosecure feeds.
Cost is more important than biosecurity although the true costs of stocking infected PLs far exceeds the costs of using biosecure sources of feeds. They test on a population basis for OIE pathogens with PCR, a tool that is not in of itself sufficient to declare a population as being SPF.
PCR is used statistically despite the fact that technologies are available which allow individual broodstock to be screened for all known pathogens quite economically. Following the history of animals’ post stocking is essential for determining the adequacy of PCR testing.
“This entails closely following what is happening in the field ensuring that when disease outbreaks occur that some understanding of where the pathogen(s) came from is important.”
This feedback is essential for true sustainability. Diseases are readily moved between farms by birds and other vectors. There are still many areas where one farms effluent is untreated influent for neighbors.
Many farms still discharge raw untreated effluent into the environment. Some collect it in sedimentation ponds before discharge.
Although some NGOs and government agencies require that effluent be held in sedimentation ponds with discharge only allowed after the water quality has reached the desirable point, this is rarely a consistent feature of production.
“At the moment the industry is seeing unprecedented differences in the supply of reefers for transporting frozen shrimp to processors and ultimately to the customers.”
Containers from SE Asia to the USA and EU are in the $15,000 to $20,000 range, contrasted with those from Ecuador being in the $6,000 range. This difference is enough to give Ecuador a price advantage beyond what they already have. This should have a dramatic impact on the export rates of several nations.
“Supply and demand certainly impact sustainability. From my perspective, the industry is moving towards sustainability although on a global basis we are still not there.”
Continuing to rely on wild animals, the lack of appropriate environmental regulation and enforcement and in general a disorganized approach towards the development of new farms all contribute to the current lack of sustainability.
Some countries are closer than others although for the most part the global industry is still many years away from being considered to be truly sustainable.
Stephen G. Newman has a bachelor’s degree from the University of Maryland in Conservation and Resource Management (ecology) and a Ph.D. from the University of Miami, in Marine Microbiology.
He has over 40 years of experience working within a range of topics and approaches on aquaculture such as water quality, animal health, biosecurity with special focus on shrimp and salmonids.
He founded Aquaintech in 1996 and continues to be CEO of this company to the present day.
It is heavily focused on providing consulting services around the world on microbial technologies and biosecurity issues.