The Symbiotic Relationship Between Gobies And Pistol Shrimp
Throughout the Atlantic, Pacific, and Indian oceans, species of Gobiid fish are known to form a symbiotic pair relationship with species of pistol shrimp of the. Genus Stonogobiops - Symbiotic Gobies, The Pinnacle of Symbiosis in the Tropical It is what Scott Michael calls an “invertebrate-fish relationship that I think is even shrimp goby-pistol shrimp relationship is a mutualistic one, meaning that. In the goby and pistol shrimp symbiosis, both animals benefit. When they are outside of the burrow, the fish keeps an eye out for predators and warns the goby .
When the female laid the eggs approximately 20,she would leave and the male would take care of the eggs, mostly inside the burrow for the next days until hatching.
The shrimp that pair are almost always of opposite sexes, except in a rare few documented cases Moering When in a pair the female is slightly larger than the male. While they may pair early on, it is not until the shrimp are about a year old that they start breeding. Females will carry approximately 4, eggs maximally.
Young, once hatched will settle alone and begin digging a hole. Pair Formation A big question for shrimp-goby researchers had always been, how do the shrimp and goby find each other? In other words, who finds who and how? The Behavioral Mechanisms Regulating Partner Specificity whereby he experimentally figured out what attracts shrimp and goby to each other.
He discovered that the mechanism for shrimp is different for that of gobies. In an nicely designed experiment he looked at two different methods of attraction, chemical and visual. The diagram to the right shows the set-up used by Karplus One partner was placed in the bottom of the V while the other was placed in one branch of the V. A partition was raised and the shrimp or goby could travel up the V into the water stream.
They found that there was no difference in which side the goby went into, regardless of what kind of shrimp was in the system. For shrimp the story is different. Tests were then conducted to see if, when the cylinder was raised, which side they attempted to go to. Karplus discovered that shrimp showed no preference for any side, no matter what was behind the glass.
What does this mean? In reality what does this mean? Does it prove who finds who in the relationship? In the wild, how often does a goby visually see a shrimp? Most of the time, the shrimp are inside their burrows.
It does show that there is a strong attraction for both shrimp and goby to their particular partner, whether it be visual for the goby or chemical for the shrimp. It also shows that the shrimp and goby are sensorialy set up very differently. Daily Rhythm Patterns Most organisms have some sort of daily activity pattern that makes the more active in the day diurnal or in the night hours nocturnal.
The shrimp and goby are no different. For every species studied to this date, activity begins with sunrise or close to itand ends at sunset when goby and shrimp retreat into the burrow and the burrow entrance collapses Magnus ; Karplus et al,; Polunin and Lubbock ; and Yanagisawa In the case of diurnal rhythms, the activity that has been mostly studied is the activity of the shrimp, whom does all the digging and burrow maintainence.
With a great deal of the studies done on shrimp gobies, have come a good understanding of the activity rhythms and some general themes amoung species. The first aspect of the rhythm is the amount of time spent outside the burrow by the shrimp see above figures Karplus Shrimp spend about one-third of their time outside the burrows in the morning, reduce the time around noon and then spend the majority of time outside the burrow at night.
These rhythms can be slightly effected by the tides too. When the water level reaches cm above the burrow, activity usually stops Karplus The activity that the shrimp performs while outside the burrow does change however. In the morning, the shrimp usually leave with their chelae full of sediment and in the afternoon they are usually empty.
Also, most of the introduction of sediment, usually in the form of organic material for food usuage later, it introduced primarily in the afteroon. Finally, the amount of burrow construction activity, in the form of reinforcing the outer walls of the burrow, are mostly performed in the afteroon Karplus The activity of the shrimp begins and ends around surnrise and sunset respectively, however, not all individuals will begin at the same time.
Shrimb-Goby Relationships: A coral reef species profile
The start of activity takes place when a goby emerges from the sand, followed by the shrimp MagnusKarplus ; Yanagisawa Its believed that the begining of activity is synchronized by some sort of endogenous rhythm, while the end of activity is usually synchronized by the light levels, and thus the later is more sychronized amoung individuals Karplus Finally, activity varies amoung the sex of the shrimp. Most of the activity outside the burrow is initiated by the male shrimp Yanagisawa Warning Communication The complexities of communication between the shrimp and the goby were first revealed by Lynn Moehring in when she produced her Master's Thesis at the University of Hawaii.
These findings were later published under her new last name, Preston, in Gobies could differentiate potential partner shrimp by sight Karplus et al.
If unsuitable partners were presented in experiments, the gobies stayed away. In reverse, the shrimp found their partners by smell. There was interest from the beginning about what the burrow looked like, but all that was visible from outside was the entrance. The tubes were filled with sand before the experiment started. After the shrimp excavated the tubes, the partnership could be viewed.
This setup, however, appeared too artificial to me. Yanagisawa even poured resin into burrow openings in the wild.
The burrows went down as far as 1. The burrow often divided, and the tunnels extended into chamberlike structures. Larger coral rubble pieces or skeleton parts of sand dollars were integrated into the burrow. My Observations These trials to find out more about the burrow system just fueled my interest to find out what was really going on inside.
Among marine aquarists, it was not even known that couples of shrimp and couples of gobies naturally live together. Most aquarists were happy to have one shrimp and one goby in their tank combined.
Where and how would they reproduce? Existing observation did not have an answer for this question. But how could I look inside the burrow? I noticed that the shrimp tended to build their burrows along the bottom glass of the tanks. Steady beating of the abdominal appendages pleopods kept the bottom glass free of sediment.
So I set up a gallon tank on a high rack, enabling me to sit below and to observe them through the bottom glass of the tank. The frame of the rack just held the tank around its circumference. To reduce any potential negative impact from light below, I covered my observation chamber with a black curtain.
The Symbiotic Relationship Between Gobies And Pistol Shrimp
I took videos or pictures with just a little light that I could switch on. Both species were caught and imported in larger numbers together from Sri Lanka. Amalgamating the couples of fish and shrimp was not an easy task.
If same sexes are in a small tank, it often ends in severe trouble—the shrimp are able to kill each other in an aquarium. Therefore I kept them as far apart as possible in separate tanks until I could identify the sexes of the shrimp female shrimp have a more broad abdomen and more broad pleopods.
I also kept the young gobies separated. By changing the partners in one tank, I could easily find out if two specimens would go together, which is the indication for different sexes. In the next step, I brought both couples together in the observation tank.
I kept the interior of the tank simple: The shrimp started building the burrow immediately after I introduced them in a little cup and directed them into a gap I made under a piece of live rock.
Then the fish were added. It did not take longer than an hour, and the double couple was together.
During the next days, the burrow grew. The shrimp transported all excavated material and pushed it outside the burrow. They used their claws to push the sand like a little bulldozer.
This astonishing skill can only be performed if the goby is out to guard their safety. When the tunnel system grew, the partner behaved differently under subterranean conditions.
The narrow space in the burrow causes them to squeeze their partners against the burrow wall. The fish tend to wiggle through the burrows with force and no hesitation toward their crustacean partners. Due to the action, parts of the burrow system would often collapse.
A fish buried under sand stays there without panic the shrimp can smell it and waits until the shrimp digs it out and begins to repair the burrow. The main way into the burrow can be up to 2 feet long during the first days of excavation.
Soon after, side ways are constructed, which can be as short as 2 inches. They can be driven forward and later form an exit to the surface, or they are extended to form a subterranean chamber. Repeatedly, I could observe the shrimp molting in these chambers.
This happens during the night every two to four weeks. The next morning, I would find exuviae close to them, and the female was carrying eggs on her abdominal legs if the shrimp are in good condition, molting and egglaying coincide.The Odd Couple: Goby Fish & Pistol Shrimp (HD)
The shrimp cut the exuviae into pieces and transported them out of the burrow as soon as their new test hardened. Hatching of the zoea larvae seems to happen overnight, which makes sense to avoid predators as long as possible. The currents caused by the beating of the pleopods must pump the eggs out of the burrows, where they become a part of the plankton. The shrimp are omnivorous and collect large pieces of frozen fish positioned close to the entrance of the burrow. They collect the food and transport it immediately into the burrow, where they feed on it.
However, outside they can also be observed eating algae growing on rocks. The shrimp directly gnaw with their mouth pieces on rock where algae is growing. Even more fascinating was that I found parts of the algae Caulerpa racemosa inside the burrow system, though it grew more in another edge of the tank. It took some time until I could observe that the shrimp cut these algae with their claws if they get access to it.
However, that can only happen when fish and shrimp are on a coexcursion outside the burrow. In one instance, after cutting, the shrimp lost the algae due to the currents in the tank. But the unexpected happened: The goby immediately took action and grabbed the Caulerpa with its mouth. That moment, the shrimp lost antenna contact with the fish and quickly rushed backward to the entrance. The goby transported the lost food to the entrance and spit it out into the entrance of the burrow where the shrimp was waiting.
The fish was actively feeding the shrimp! I tested this observation and pulled algae off the rocks.