Shortfin mako  (Isurus oxyrinchus)

The shortfin mako is caught both by targeted fisheries and as significant bycatch, being the major bycatch component of tuna and swordfish fisheries (1) (3). The species’ is valued for its high-quality meat, its fins are marketed for shark-fin soup in the Far East, and its liver oil is extracted to make vitamins (2) (3). The jaws and teeth are also sold as ornaments and trophies, and the hides may be processed into leather (2) (9). Sadly, the shortfin mako is also considered one of the great game fishes of the world, prized for its beauty, aggressiveness, and spectacular aerial leaps when struggling against the fishing line (3) (10). The highest recreational catches occur off southern California, the north-eastern United States, Australia and New Zealand (3). Most commercial catches are inadequately or un-recorded, and conflicting data make it difficult to evaluate the exact impact fishing is having on population numbers of this shark (1) (9). However, like other sharks, this species’ relatively low reproductive capacity makes it vulnerable to population declines due to over-fishing (1). Fortunately, this shark’s fast growth rate means it has a mid-range rebound potential. This, combined with its world-wide distribution and relative abundance, means that the species is currently reasonably safe from the threat of extinction (9).

The U.S. National Marine Fisheries Service (NMFS) has included the shortfin mako on their list of managed pelagic sharks, and reduced the number of commercial and recreational catches allowed per year by 50 percent. Although it is hoped that this measure will help to counteract declining numbers, the regulations only apply to the United States and Gulf waters, while the other populations remain as vulnerable as ever (3). A short-lived experimental longline fishery was once used to target early juveniles off California, but it was closed in 1992 due to concerns over the exploitation of immature fish. Targeting juveniles means these individuals are killed before ever reproducing, exacerbating the species’ decline (9). Although currently classified only as Lower Risk / Near Threatened on the IUCN Red List 2007 (1), the shortfin mako, like any other shark, is susceptible to over-fishing if not carefully managed (9). Thus, protective measures and fishing quotas implemented by other fishing nations would greatly help to safeguard the future of this magnificent, leaping shark, for years to come.