Development of tagging techniques for monitoring fish populations at Texas artificial reefs

Abstract

Texas Parks and Wildlife Department (TPWD) has used a broad range of methodologies to monitor the social, economic, and biological impacts of artificial reefs in the Gulf of Mexico. Social and economic issues have been addressed through charter boat and diver mail-in questionnaire surveys and on-site creel surveys. Biological issues have been investigated through hook and line tagging, diver-based visual transects, and video traps. Assessments of hydroacoustic and remotely operated vehicle (ROV) biological survey techniques are also planned for deepwater reef sites. There is also a need to develop inexpensive biological monitoring methods to track target fish populations such as red snapper over time at specific reef sites. The Department has been investigating the use of collapsible traps to tag fish underwater as a potential long-term monitoring tool for assessing reef fish populations. The cost effectiveness and efficiency of this gear type was compared to hook and line capture techniques. During the initial effort, 223 red snapper were tagged underwater by divers after capture by three collapsible traps, and 291 red snapper were tagged on the surface by anglers after capture by hook and line techniques. The collapsible traps appeared to be more size selective for smaller sized red snapper than hook and line techniques. Fish tagged underwater had a higher recapture rate of 25.45 percent compared to the 11.89 percent recapture rate for fish caught and tagged on the surface. Although three recapture periods were used to evaluate tag return data, our findings suggest that future efforts directed at monitoring artificial reef fish populations should use multiple gear types with equal effort applied to account for size-selective capture patterns and logistical constraints.