Visitas: 127
* By Ph.D. Stephen Newman
Climate is a complex phenomenon that shapes the habitability of environments. Climates are constantly evolving in response to many variables. These changes can have broad impacts on plants and animals, usually as a result of small changes over time, but on occasion large changes can and do occur quickly.
Among the changing variables are the greenhouse gases. These include water vapor, methane and carbon dioxide. Carbon dioxide levels in May of 2024 reached the highest recorded levels since humanity started keeping records. The levels were 3% higher compared with the same time period last year.
This is the greatest single increase recorded and indicative of what lies ahead. Some of the variables are impacted as a result of the nature of Earths ecology, the influence of the sun, the tilt of the Earth’s axis, etc. Some are the result of human activity, such as damaging environments via practices that are essentially not sustainable. Pollution is a catch all term for the addition of substances to the environment that have a negative impact.
There are many examples where human activities have impacted the climate.
Globally we are also seeing a reduction in oxygen levels in many fresh and saltwater ecosystems. These include widespread desertification (the Sahara was once a lush tropical forest) and increased frequency and types of algae blooms in estuaries and other bodies of water.
Add to this the presence of regional temperature fluctuations that make the environment inhospitable to the normal activities of humans and other animals and the scenario has been set for a warmer world with its challenges.
At the moment, Earth is in the midst of a cycle that is between an ice-age and a much warmer planet. One must recognize that humans can have profound negative impacts on their environment. As the human population continues to increase, this can shape environments in ways that make them less hospitable for human beings.
What is occurring is quite complex. Climate change is inexorable and normal although human influence is pernicious. Humanity collectively is certain to increasingly comprehend the nature of the factors that are elements of the changes we are seeing.
For now, though what is quite apparent is that human activity is increasing the amount of carbon dioxide in the atmosphere and that there is no evidence to the contrary.
With that said, the purpose of what I am writing is not to persuade the reader one way or another as to the causes, but only to consider that many agricultural activities remain to be impacted and that the rapidly growing international aquaculture productivity is highly vulnerable to negative impacts.
Global average temperatures are increasing, and we are seeing new records being set every year. There are potential huge indirect impacts. This heating is causing huge areas of permafrost, permanently frozen ground, to thaw, releasing methane, a by product of bacterial decomposition of plant matter and a very potent greenhouse gas.
All indications are that it appears highly likely that short of an event that causes rapid dramatic cooling (such as a very large volcanic explosion, Earth being struck by a large asteroid or, heaven forbid, a nuclear war) the trend will be to see gradual but rapidly increasing global atmospheric and ocean temperatures.
The extent of the impact will depend on how high the average increases are and how these impact overall climatic conditions. Even if humanity can slow the rate of increase or bring it to a halt, the impact will not go away.
One observation that is apparent is that not everywhere is impacted in the same manner. Periodic climate trends, such as those from El Niño and La Niña can and do impact certain areas geographically. As record keeping trends reveal, the overall trend appears to be towards increased Ocean water temperatures along with increases in Ocean levels as ice melts from Glaciers, etc. There is no sign that this is slowing down. All indicators show that these are increasing.
My thesis here is to speculate on what the impact will be on the global aquaculture industry which is wholly dependent on access to environments that are conducive to the optimum production of the species being farmed.
Aquaculture is the production of animals and plants in aquatic ecosystems. As global population continues to increase, the need for high quality and minimally disruptive sustainable technologies for food production are essential.
When practiced responsibly using truly sustainable practices, aquaculture is a valuable source of low-priced nourishing protein. Although aquaculture is not conducted everywhere in a responsible manner, it is widely recognized that we must move towards this. Polluted environments are not conducive to optimum, profitable aquaculture production.
It is highly likely that the climate changes that are occurring will impact aquaculture regionally initially. I would expect that what we will see is areas where the ability to produce an aquatic animal year-round is no longer possible. There will be times when the environment is not suitable for the production of the species that have been traditionally farmed in these areas.
Of course, it follows as well that natural populations will be affected and that they will either adapt or relocate where possible to less hostile, ecologically friendlier, environments. Farmers can shorten cycles and let ponds and or cages fallow during the months when temperatures are too high for production. In some cases, they may be able to offset minor changes by digging deeper ponds or submerging cages into cooler waters. In others not so.
The graph below shows how average monthly global temperatures have been increasing more or less consistently from the year 2000 on. It is evident that both the rate and the quantity are increasing.
While there is a certain amount of unpredictability as to where and what types of production paradigms will be impacted and to what extent, what it is evident that we need to take steps to minimize this gradually increasing impact. If we do not, the consequences will be the loss of or at the very least a decrease of production capacity.
Indoor production using recirculating systems (RAS) offers some hope to offset some of this although it is highly unlikely that RAS will be able to replace the overall volumes.
While this technology is still maturing in a sense, the overall costs tend to be much higher than current open environment practices. Note that this is not black and white.
At this point in my life, I am quite cynical about humanity’s ability to address this in a logical manner.
It does not appear that we can stop the global freight train that overpopulation is ensuring is bearing down on humanity. While there are some that will tell you that there are sufficient resources that if more uniformly available would ensure adequate nutrition for all, I see this as wishful thinking.
Others will tell you that the Earth’s resources are being depleted at an alarming rate and that if we don’t pare our population down, we will shape environments that are hostile for agriculture and thus human sustainability.
Aquaculture will be affected inseveral ways. One will be that areas that have been friendly to cage culture in shallow environments will no longer be. One must also consider that production requires sources of nutrients. Shrimp and fish need manufactured feeds to ensure acceptable growth rates and reasonable costs of production.
Fish meal is a major component of the feed for many farmed marine animals, and it relies on dense populations of species that are not widely used for food. It is highly likely that these environments will be impacted and that this will either presage an extinction event or the populations will migrate to less stressful environments.
Access to food is a critical element of this. There are no crystal balls. However, there is little if any doubt that anthropogenic influences are impacting that rate and manner of climate change. While at the moment we are in the early stages of the disruption that this will bring about, it is essential that we model the potential impacts and plan accordingly for aquaculture to become truly sustainable.
The wild fisheries are being impacted as I write. Salmon runs (baby salmon smolts moving from their freshwater places of birth to the open ocean) are being impacted by high temperatures in critical water pathways to the ocean.
High levels of mortality have been observed in some runs and proposed solutions are to truck animals to avoid these areas. As the waters continue to warm this will have challenges. Oxygen levels are decreasing globally in many fresh and saltwater environments. What can be done?
Genetic improvement of animal’s ability to tolerate the extremes that are likely to become the norm is one possibility although there are more than likely practical limits in terms of what temperatures and other environmental extremes animals can tolerate and for how long before they deteriorate.
Weakened animals are typically susceptible to pathogens and obligate pathogen levels required to produce disease may lessen and any number of opportunistic pathogens may become increasingly lethal. Initially more than likely, we will see a geographic shift to allow production in areas that are more suitable.
As climate change continues, these will become fewer and fewer. RAS offers some potential, but as alluded to earlier, it cannot economically replace all of the species being reared in economically viable manners.
Shortages of specific species will impact their availability and in turn will drive up prices. This will limit demand and eventually some species may simply be too costly to produce economically. As traditional areas of production become less able to sustain the levels of historic production, either they will attempt to relocate, or productivity will wane in some instances to the point where there is little if any production.
Given that it is speculative as to the rate and locations where this will occur, it will be a huge challenge to ensure that sustainable production paradigms take this into account. Time will tell. The traditional poverty driven production paradigms in some parts of the world will more than likely fade away.
Larger vertically integrated corporate producers will relocate where resources allow although it is far from certain where all of this will end up. Some predict that large swatches of those areas that humans currently live in will become too hostile for daily living and that there will be forced mass migrations.
Others speculate humans will adapt and that there will be a limit to the impact. Regardless it is highly probable that all agricultural practices whether it is producing wheat, farming chickens and beef or aquaculture will be adversely impacted.
* 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.
sgnewm@aqua-in-tech.com
www.aqua-in-tech.com
www.bioremediationaquaculture.com
www.sustainablegreenaquaculture.com.
