1. Dec, 2018

Bimini and Tiger Beach, similarities and differences

Tiger Beach  is a remote spot at the edge of the little Bahamas banks, about one and a half hour boat ride from West End Grand Bahamas. It had already built its reputation as a shark sanctuary in the late 90ties. Jim Abernethy was then one of the very first operators who organized live-aboard trips with Shear Water departing from West Palm Beach in Florida. The site also gained its reputation from the variety of sharks: Tiger, Lemons, Caribbean reef sharks and occasional visits of the Great hammerhead (GHHs). Some of the tiger sharks have reached a star status, with names as Emma (no doubt the grandmother of a large offspring), Jamin, Hook, Lady, Princess, and Tequila. Tiger Beach is also considered as a safe haven for female tiger sharks to mature, gestate, and give birth to their pups.

Bimini is the best place for meeting the GHH (Sphyrna Mokkaran) 65 miles south of  West End. A shy and mostly solitary species, unlike its cousin the Scalloped hammerhead (Sphyrna lewini) Large and increasingly rare GHHs are really difficult to meet underwater. Every winter a healthy population of GHs gathers just off the coast of Southisland. Their annual aggregation was discovered by the staff of Dr. Samuel Gruber’s Bimini Shark Lab back in 2002. But the lab managed to keep the whole thing to themselves for over 10 years. When the word eventually got out, South Bimini became firmly established as a tourist eco site to meet  GHHs from a close distance. Bahamian Neal Watson started organizing baited GHH safaris around 2012, now using the Big Game Club as his home base. The underwater scene at Bimini is different from that of Tiger beach, with Nurse sharks often visiting the baiting sites at South Island as ‘entourage’ of the GHHs. Occasionally a Bull shark from North Island may join the baiting party while keeping its distance. Although Tiger sharks do not mix with GHHs at South Island, they have been spotted around Bimini. From one particular pregnant female marine investigator James Sulikowsky has even been able to visualize the pups with a sonogram

Most of the 20 hammies showing up at Bimini South Island have been tagged by the Shark lab for studying their migratory behavior. The large areas of mangroves and sea-grass  at Bimini are an ideal nursery for young sharks, in particular baby lemons sharks. Bimini is also uniquely placed to benefit from the life-flow of the adjacent Gulfstream providing the eggs and larvae to grow into crabs, lobsters, and conch. And providing a source of food for the large predators. GHHs annual return in the winter season, however, is believed to be triggered not for mating or giving birth for but feeding purposes, with stingrays and crabs serving as their favorite dish. During their migratory leave in spring, triggered by rising water temperatures, GHs have been tracked while visiting coastal waters in Florida as well as Virginia, probably also the sites where they meet the ‘boys’ to mate with. Some exchange of sharks between Bimini and TB may also take place. For example, a notorious female GHH resident of Bimini, intermittently called ‘Patches’, ‘Bite Back’ or ‘Scylla’, has now also become a regular visitor of Tiger beach (see insert).

Sources

 Sulikowski, James A. et al. Seasonal and life-stage variation in the reproductive ecology of a marine apex predator, the tiger shark, Galeocerdo cuvier, at a protected female-dominated site. Aquatic Biology. Vol. 24: 175-184. February 22, 2016. 

https://www.frontiersin.org/articles/10.3389/fmars.2017.00003/full

http://www.albertkokuw.nl/422867045/4435555/posting/migration-and-residency-of-the-great-hammerhead

https://indopacificimages.com/great-hammerhead-sharks-of-bimini/

https://www.youtube.com/watch?v=5MEYuPVtDKA.