Apparent survival of North Atlantic right whales after entanglement in fishing gear

Documented entanglements, long-term population studies and mark-recapture studies were evaluated to determine the impact of cryptic mortality on North Atlantic right whales. Results suggest entangled adults had low initial survival (0.749). Adults that did survive the first year had survival rates similar (0.952) to those animals never entangled (0.961 female and 0.986 male). Juveniles had post entanglement survival rates similar to initial survival rates of entangled adults, 0.733, but lower than un-impacted juveniles (0.978). Health impacts were the most predictive aspect of subsequent survival. In addition, entanglement configuration and resulting injuries also affected the final outcome. Human interventions appear to improve survival outcomes for entangled whales.