Commercial fishing and bycatch are by no means the only threat to sharks. Sport anglers find great thrills in catching sharks. Mouth-hooked mako and thresher sharks often display acrobatic jumps out of the water while being reeled in. One big problem with fishing sharks for sport is that there is no way to accurately keep track of how many are being killed because anyone with a license can go out and catch their share. In fact, you don't even need to have a boat as thresher sharks are often caught by fishermen on kayaks. Sharks off of the coast of Southern California have not recovered from the overfishing of the early 1980's and they continue to be hit hard by gillnets. One phrase we hear all to often lately is "there just aren't as many of them out there anymore." If you must fish sharks for sport, the responsible thing to do is to catch-and-release it. That being said, it is also very important to do so using fishing practices that will increase the chance of survivability of the shark.

Thresher and mako shark tournaments are held three to five times a year in Southern California. The good news here is that many of these anglers catch-and-release most of the sharks caught during these tournaments and have participated in helping scientists learn more about alternative fishing methods that increase post-release survivability.

In spring 2007, a collaborative Bycatch Reduction and Engineering Program (BREP) project was initiated by the SWFSC, Southwest Region Sustainable Fisheries Division, and Pfleger Institute of Environmental Research to study the first post-release mortality estimate for common thresher sharks captured in the recreational fishery off Southern California and to develop and promote alternative fishing methods which increase post-release survivabilty. Although accurate landings data are lacking for this species, direct observations, fishing tackle sales, and weigh-station records all indicate a dramatic increase in fishing effort over the past six years. The primary technique developed in the recreational thresher shark fishery involves trolling heavy baited lures with large J-type hooks. Since thresher sharks utilize their elongate upper caudal fin lobe to stun live prey before it is consumed, more than 90% of sharks are foul hooked and subsequently hauled in backwards during the fight. Sharks are not able to swim backwards. When sharks are hauled in backwards, it increases fight times and can be very stressful and sometimes deadly to the shark due to limited water flow accross the gills.

A total of 42 thresher sharks were caught and released over the course of the study at a sex ratio of two females to every one male. 93% of captured thresher sharks were hooked in the dorsal lobe of the caudal fin while trolling heavy baited lures with 8/0 J-type hooks. Foul-hooked juvenile and small sub-adults (102 to 152 cm FL) incurred fight times ranging from 9 to 42 minutes on 36-kg conventional tackle and remained vigorous when brought alongside the tagging vessel prior to release. 22 juvenile and sub-adults were affixed with conventional dart tags and released in good condition. Similarly, all mouth-hooked thresher sharks remained active at the side of the boat regardless of fight time. Pop-off satellite archival transmitters (PSAT) were deployed on 18 large sub-adult and adult thresher sharks ranging in size from 160 to 230 cm fork length. Upon capture, larger individuals were generally exhausted and lethargic following fight times ranging from 45 to 140 minutes; however, as determined by PSAT records all individuals with fight times less than 75 minutes were able to recover and survive the acute effects of capture. Immediate post-release mortality was observed in all five thresher sharks (205-230 cm FL, 3 female: 2 male) that incurred fight times in excess of 85 minutes. The resultant post-release mortality estimate in this study was 26 percent for adult and large sub-adult thresher sharks (160-230 cm FL). Results suggest that large tail-hooked thresher sharks exposed to prolonged fight times (>85 min) have increased mortality rates when compared to smaller individuals.

Experimental gear trials were conducted in 2009 to capture mouth-hooked thresher sharks for comparative blood biochemistry assessments. Artificial lead-headed lures were baited with live chub mackerel Scomber japonicas tethered to hookless lures using wire ties and slow trolled with a light drag clicker. Circle hooks, size 9/0, baited with dead mackerel were rigged on separate rods and dropped back towards the slow-trolled lures upon detection of a caudal-fin strike. Six of the 10 individuals caught using this drop-back technique were hooked directly in the mouth, although the use of circle hooks did not eliminate the incidence of foul-hooking in all thresher sharks. Initial gear trials indicate that the use of circle hooks may significantly reduce the number of foul-hooked sharks captured in the recreational fishery; however, additional field trials are necessary to determine the effectiveness of this gear modification and to further develop techniques to reduce overall post-release mortality.
A strong public outreach component was incorporated into this project to compel active participants in the fishery to assist in the development of alternative fishing methods that reduce foul-hooking and increase mouth-hooking. Over 500 recreational fishermen attended the six seminars offered in 2008 and 2009, with over a dozen dedicated anglers willing to participate in the additional gear trials.

• Circle hooks reduce shark mortality. The use of large stainless J-hooks is not a good idea if you intend to release the shark.

Shark Free Santa Barbara wants to get the word out about these findings and work with recreational fishermen and local shark tournaments to help reduce overall shark mortality by switching to 100% catch-and-release of all sharks caught, using the best fishing practices possible. Please contact us if you are interested. If you know anyone that catches sharks for sport, please print out this brochure and give it to them.