Dictionary of Ichthyology  

shelter = an artificial structure made from twigs, brush, branches, concrete blocks, etc. as a refuge or hiding place for fish at which they are also easily caught. See fish apartment house.

From Umali, A. F. 1950. Guide to the classification of fishing gear in the Philippines. Research Report 17, Fish and Wildlife Service, U.S. Department of the Interior, Washington.

Canadian Museum of Nature