Hooked on fishing? Recreational angling interactions with the critically endangered grey nurse shark Carcharias taurus in eastern Australia

Abstract

The grey nurse shark Carcharias taurus is critically endangered in eastern Australia. Although fully protected, instances of recreational hooking persist in this population, with potentially fatal consequences. Here we used in situ underwater video to quantify the rates at which C. taurus interacts with a range of proximately deployed recreational fishing gears, and we suggest appropriate management changes to limit such interactions. Bottom-set baits elicited strong responses, with 15 to 43% of whole and filleted mackerel baits depredated within 5 min. Smaller Australian sardine (pilchard) and squid baits were taken by C. taurus at a significantly lower, yet appreciable rate of 3 to 15%. These smaller baits were depredated more by recreationally important teleosts, although this relationship was not significant for sardine baits. There was no consistent diel influence on shark bait depredation, although C. taurus was the only nocturnal bait depredator. Trolled gears posed no direct threat to C. taurus at any time, even when trolled at depth. Benthic-oriented jigs were rarely snapped at by C. taurus, yet may still pose a foul-hooking risk as sharks showed a propensity to rub against these jigs at depth. Vertical jigs elicited little response by C. taurus, although foul-hooking was also a risk as jigs contacted sharks in 5% of proximate drops, with near misses or line-only interactions occurring in a further 6% of cases. Our findings suggest that restricting bottom-set baits and benthic-oriented gears such as jigs around C. taurus aggregations would be a feasible and enforceable strategy to minimise recreational fishing interactions. © Inter-Research 2013.