Every aspect of our data gathering process is designed to minimize harm to our research subjects. We use special fishing and tagging gear intended to reduce stress, shorten handling time and promote shark safety.
The Shark Research & Conservation Program uses special fishing units called drumlines (composed of a single weight and attached hook & line) that promotes shark vitality when fishing for sharks. The gear permits species which are ram ventilaters (need to keep moving to breathe) to swim in big circles around the weight when caught. The ability to swim relatively freely also minimizes stress-related C02 and lactic acid buildup in shark muscle. This gear promotes shark survival.
Circle hooks can help reduce negative outcomes for captured sharks over other commonly used hooks, most notably J hooks. Circle hooks are designed to catch in the shark’s jaw, instead of catching on the shark’s stomach or gills, which can otherwise cause serious injury. The hooks can also easily be removed from the jaw and leave a very superficial wound that heals very quickly. Circle hooks also help us selectively target sharks, reducing unwanted bycatch of other species. We recommend circle hooks not only for research-related capture, but for recreational fishermen practicing catch and release fishing who want to increase the likelihood of release their catches in good condition.
When a caught shark is brought onto a specialized, partly-submerged, platform on the back of our research vessel, a saltwater pump is immediately placed in the sharks’ mouth. This allows highly oxygenated water to flow over its gills throughout the shark’s brief ”check-up.” During this workup, sharks have a small muscle biopsy taken (recaptured sharks demonstrate that the biopsy site is completely healed within just a few weeks), are tagged with a spaghetti tag in their dorsal fin (where they have no nerve endings and no blood vessels), have blood drawn, are measured, have a small clip of their fin cartilage taken, and are released.
The traditional method for getting the type of data we collect was to kill the animals. Although capture may still be a relatively stressful process for sharks, our work focuses on minimizing shark stress to the greatest extent possible and promoting shark vitality and survival.