In situ Tagging of Nassau Grouper Epinephelus striatus Using Closed-Circuit Rebreathers at a Spawning Aggregation in Puerto Rico

Abstract

Acoustic telemetry is a widely used technique employed to better understand fish movement patterns across seascapes. Traditionally, surgical acoustic transmitter implantation is conducted at the surface, resulting in a high degree of uncertainty as to the post-release survival of the fish and the validity of the results attained from these experiments. Few studies have conducted In situ tagging, where the capture, tagging, and release are completed entirely at the depth in which the fish occurs naturally. Through the use of closed-circuit rebreather (CCR) technology, this study outlines the first known practical application of the methodology performed at mesophotic depths. In six dives conducted at depths between 40 and 50 m, a total of 10 Nassau grouper were tagged at a spawning aggregation off the west coast of Puerto Rico. The total time (time divers arrived at the trap to time of release) for each procedure was approximately 12 min, after which all fish were released and observed without indication of stress or physiological impairment. Short-term tracking of tagged fish revealed a 100% post-surgery survival rate with maximum detection of 347 days post-surgery. Survival rates of this nature have not been quantified or reported from other tagging studies, allowing the researchers to conclude that this methodology, coupled with the efficiency provided by CCR at these depths, enhanced survivorship and bias for studies utilizing acoustic telemetry.

Grouper Tales: Use of Acoustic Telemetry to Evaluate Grouper Movements at Western Dry Rocks in the Florida Keys

“…() and Tuohy et al. (). Fish were retrieved from the traps by using a plastic‐coated net and were held ventral side up with the eyes covered, inducing a catatonic state considered to be an ethical alternative to sedatives (Lowerre‐Barbieri et al.…”

“…All fish were captured using baited chevron traps. Tagging was performed in situ (12-34 m) to reduce fish stress, similar to methods described by Feeley et al (2018) and Tuohy et al (2015). Fish were retrieved from the traps by using a plastic-coated net and were held ventral side up with the eyes covered, inducing a catatonic state considered to be an ethical alternative to sedatives (Lowerre- Barbieri et al 2014).…”

Under pressure: Comparing in situ and boat tagging methods using time-to-event analyses

“…In this study, there were several variables that could not be included in the initial hazards model because of correlation, but their inclusion and limited in uence in the subsequent boat tagged and in situ tagged models reinforced that the tagging method was the most important factor in risk of disappearance from the array. Acoustic tracking data of in situ surgically tagged sh from two other telemetry studies also demonstrate the bene t of tagging method, indicated by high survival rates (97%-100%) post-surgery (Tuohy et al 2015, Bryan et al 2019. The decrease in probability of presence of boat-tagged sh could be due to several factors.…”

Under Pressure: Comparing Fish Survivorship Between in Situ and Boat Tagging Methods Using Internal Acoustic Tags

“…In this study, there were several variables that could not be included in the initial hazards model because of correlation, but their inclusion and limited in uence in the two subsequent models assessing hazards to the boat-tagged and in situ tagged sh independently reinforced that the tagging method was the most important factor for survivorship. Acoustic tracking data of in situ surgically tagged sh from two other studies also indicated high survival rates (97-100%) post-surgery (Tuohy et al 2015, Bryan et al 2019).…”