Dear Ali

Luminescent bacteria are found in free-living, symbiotic, saprophytic or parasitic relationships. The symbiotic relationship between Euprymna scolopes, a small Hawaiian squid, and Vibrio fischeri provides an example of specific cooperativity during the development and growth of both organisms

Hello Ali,

I am not sure what you mean by 'dam', but in the Hawaiian bobtail squid (Euprymna, scolopes) example, mentioned by Alaa, Vibrio fischeri are indeed first free-living and then colonize the light organ of the squid once they are hatched from their eggs. The squid are NOT born with V. fischeri so they must acquire the bacteria horizontally from the environment using cilliated appendages of their light organ and ventilation by their mantel that draws in bacteria filled seawater towards the light organ. Once the squid and V. fischeri relationship matures the squid will actually vent about 95% of V. fischeri into the environment every morning, while keeping the rest to grow for bioluminescence at night. This ensures that there is an adequate population of free-living V. fischeri in the water column to effectively inoculate the next generation of squid. I hope this helps!

Well Alexandrea Duscher, this is very comprehensive and added to much information. Many thanks for all of this!  My extended and best regards to you! 

Vibrio fischeri was reclassified as Aliivibrio fischeri gen. nov. comb. nov.

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Urbanczyk et al. (2007) Int J Syst Evol Microbiol 57: 2823-2829.

https://www.ncbi.nlm.nih.gov/pubmed/18048732

Many thanks Martin Klvana 

Hello, Dr. 

this link can explain  some informations about relationship between them 

http://serc.carleton.edu/microbelife/topics/marinesymbiosis/squid-vibrio/index.html