Why Do Brine Shrimp Occasionally Have Different Colors?

   The color brine shrimp have is mainly caused by the salinity level of the water body the shrimp are/were living in; this salinity level exerts an effect on the color of brine shrimp in 2 ways.

   Brine shrimp live in saline ponds, saline lakes and salt evaporation ponds worldwide. They are filter-feeders and continuously feed themselves with microalgae, bacteria and stirred up detritus. Depending on the salinity of the body of water they are living in different kinds of microalgae will be present as not all species of algae can tolerate higher salinities. Brine shrimp living in ponds having a lower salinity (but still rather high, at least such a high salinity that fish can not survive in it anymore) are generally greenish in color (or have a ‘greenish-bluish’ metallic shine) as there still are plenty of different algae species to feed on in these ponds. But as salinity increases, less and less algae species are able to tolerate the high osmotic pressure exerted by the saline water, and as such higher salinity ponds contain only a couple of algae species anymore. Most of these halophile (which means ‘salt tolerant’) algae species have a red, orange or even purple color, caused by the large amount of betacarotene and other carotenoids these algae produce. Carotenoids help algae to protect themselves from the high light intensities and the accompanying high amount of UV radiation they are subjected to as the water of these high salinity ponds is extremely clear. As less and less organisms can tolerate the high salinity, the water becomes clearer (few other organisms can live in it anymore besides some halophile bacteria and algae). Through the consumption of these algae the brine shrimp obtain the carotenoids and deposit them throughout their body for the same reason algae synthesize carotenoids: to protect themselves against oxidative damage due to the intense UV radiation they are exposed to. Carotenoids are known to be very efficient scavengers of singlet oxygen & peroxyl radicals[1]. So brine shrimp harvested from high salinity ponds have a very red color as pictured below.

   The second way salinity exerts an influence on the color of brine shrimp is caused by the fact that water of a higher salinity can contain less dissolved oxygen. So in order to compensate for the lower availability of oxygen brine shrimp living in these waters make more haemoglobin, which naturally makes them appear more red.

   All brine shrimp we sell are were harvested from solar evaporation ponds in the surrounding saltworks. When investigating whether the brine shrimp in a certain pond can be harvested, a lot of things need to be taken into consideration, such as:

• Is the brine shrimp population mature enough? If too many nauplii (very young brine shrimp) and juvenile shrimp are still present whilst adult shrimp can be hardly seen, we will overharvest the population by removing too much of its reproductive potential. Obviously this must be avoided at all cost.
• Is there any organic debris floating in the pond or lake? Sometimes large amounts of pollen, catkin or empty brine fly casings have been deposited on the water surface, making the harvested brine shrimp too difficult to clean.
• Is a benthic algae mat present where we plan to harvest? And if so, in what condition is it? Parts of the benthic algae mats occasionally break up and come floating to the water surface, especially after a substantial amount of rain has fallen. If a large amount of algae matter is present it becomes near to impossible to separate these algae strands from the brine shrimp after being harvested.
• Is the part of the pond or lake deep enough to harvest brine shrimp without harvesting unwanted brine fly larvae as well?
• What’s the weather forecast? If strong winds are predicted to occur the wind will blow the brine shrimp leeward side where they will get mixed up with foam, scum, empty brine fly casings, empty cysts and other debris also being blown leeward side. It will be advisable to look for brine shrimp in the more sheltered areas of the pond or lake or just forego harvesting that day.
• Is it going to be a sunny or cloudy day? As adult brine shrimp are negatively photo-tactic (they move away from strong light) they will move to the deeper parts of the lake or pond during a sunny day. On a cloudy day the shrimp will be found more dispersed over the pond or lake.
• Are people planning to move a substantial amount of water between successive ponds in the evaporative pond chain?

Because of these reasons, amongst others, we need to harvest brine shrimp from different ponds or different parts of a lake and as such, different batches of harvested brine shrimp might have different colors. When differently colored batches of brine shrimp are harvested on the same day, we mix the batches in order to come up with a uniform product.