Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures

Post-Release Survival and Habitat Utilization of Juvenile Swordfish in the Florida Straits

Event Name/Location

32nd Annual Meeting of the Florida Chapter of the American Fisheries Society, Altoona, Florida, February 21-23, 2012

Presentation Date


Document Type

Conference Proceeding




The use of pop-up satellite archival tags (PSATs) allows a researcher to overcome limitations associated with acoustic, conventional, or archival type tags. With PSATs, both data collection and retrieval are fishery-independent. Previous research techniques have provided information on longer-term movements, migrations, and behavior patterns, but there is still a need for additional tagging studies with “second generation” tags with depth and light data and increased memory that will further define the short-duration activity patterns and habitat utilization of juvenile swordfish in the North Atlantic. PSATs have been successfully used on other large pelagic fishes, but have yet to be used on juvenile swordfish. This project investigates two topics: the post-release survival rates of twenty juvenile swordfish after being released from the recreational rod-and-reel fishery or buoy fishery in the Florida Straits, and habitat utilization of juvenile swordfish following release. High-resolution PSAT technology is being used to estimate post-release survival, analysis will be done using the “Release Mortality” program. A deterministic, periodic model is being developed to fit to the data and describe the fishes’ habitat utilization. This model has four amplitude parameters, two each for the daily and lunar cycle, and a mean depth value. Data gathered by the PSATs will also be used to analyze behavioral interactions with the fishing gear and compared with other descriptions of swordfish behavior. This study is a collaborative effort with the local recreational and buoy swordfish fishery, utilizing local fishermen to conduct the field work. Data from this study will aid in determining better management practices in terms of the efficacy of mandatory release of undersized fish. The data from the tags will also provide experimentally-generated estimates of recreational fishing mortality that can be used in stock assessments conducted by the international management body for swordfish, the International Commission for the Conservation of Atlantic Tunas (ICCAT).

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