Goby | fish | meer-bezoekers.info
Blind goby: perciform: Interspecific relationships: The blind goby, Typhlogobius californiensis, depends entirely upon holes dug by the ghost shrimp. In the goby and pistol shrimp symbiosis, both animals benefit. . The gobies can successfully mate only when the shrimp are healthy and have hard tests. Dec 1, One of the more curious relationships that most divers would have come The Pistol Shrimp or Snapping Shrimps of the Alpheus shrimp.
The goby is capable of communicating levels of danger to the shrimp. Thus, the shrimp sometimes respond to signals from the goby by working closer to the burrow opening, sometimes by working in the actual burrow opening, and sometimes by totally retreating into the burrow itself.
This quite detailed interspecific communication is very rare in nature, at least when invertebrates such as shrimp are parts of the interaction.
Goby with partner shrimp The actual method of the communication between the pair is performed by contact of one of the very long antennas of the shrimp to the posterior dorsal fin of the goby. When the shrimp wants to get out of the burrow the shrimp first extends one of the antennae out of the opening, contacting the fin of the goby.
If the coast is clear, the goby wiggles its fin in a certain way, telling the shrimp that it can come out. As long as the shrimp is outside the burrow, its antenna will be touching the gobies fin. Goby with partner shrimp How about nighttime, then? During the dark hours, he goby cannot see much. The burrow then turns into more of a trap than a refuge, as many of the small eels hunting on the sand can also penetrate the burrow, thus capturing both the goby and the shrimp.
Luckily the shrimp and the goby have a solution for that. Outside the burrow entry there are always small pebbles scattered. When dusk falls, after the goby has retreated down into the burrow, the shrimp uses these pebbles to close the burrow, Thus, with the burrow entry securely closed, the couple can spend the rest of the night in safety.
More often, a couple of gobies and a couple of shrimp were found in one burrow. To observe the association in aquaria was another approach to find out more. The partners had to find each other in a Y-shaped testing channel, either by optical or olfactory abilities. The shrimp did not show any optical orientation at all, but the gobies did. Gobies could differentiate potential partner shrimp by sight Karplus et al.
The blind shrimp and the macaroni goby
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.
Symbiosis ( Read ) | Biology | CK Foundation
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 Symbiotic Relationship Between Gobies And Pistol Shrimp
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 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.