Thought-about to be essentially the most stunning island on the earth by Jacques Cousteau, the island of Cocos situated 350 miles off Costa Rica is a sight to behold each above and beneath the waves. Proclaimed because the “island of sharks,” these waters are recognized to harbor a range of enormous pelagic species together with sharks together with hammerheads, Galápagos, silky, tiger, white tip reef and whale sharks. This haven for scientists, divers, and marine fanatics alike has been featured in lots of documentaries, together with this 12 months’s upcoming Shark Week episode “Rogue Tiger Shark: The Hunt for Lagertha.”
Tiger sharks (Galeocerdo cuvier) are an iconic predator with international distribution in our warm-temperate and tropical marine waters, simply identifiable as a result of their vibrant stripes that fade with age. Regardless of their vital position in tropical reef ecosystems worldwide, scientists haven’t been capable of determine the habitats the place these animals mate and provides delivery (i.e. pupping and nursery areas). Whereas this new Shark Week present appears to have a look at bigger tiger sharks, a crew of scientists revealed an article that seemed on the tiniest of tiger sharks: juveniles.
The seamounts, islets, and bays of the Cocos Island Nationwide Park are important habitats for quite a lot of animals who name this World Heritage web site residence… may the identical be true for tiger sharks? Afterall, these sharks haven’t been noticed utilizing particular places as a nursery space, though there’s some proof they may have particular pupping habitats round Hawaii and the Bahamas. So whereas it isn’t unusual to see giant tiger sharks within the protected waters of Cocos Island – long run information exhibits the primary data of tiger sharks was again in 2008 and sightings have solely elevated – it was a bit shocking to see a possible neonate caught on movie because of a baited distant underwater video station (BRUVs). Regardless of over 25 years of shark observations right here, there isn’t a proof up to now to help that tiger sharks use this island as a birthing web site, though on a number of events and completely different occasions of the 12 months feminine sharks have appeared a bit rounder than traditional. Pregnant… or simply had a very massive meal? It isn’t precisely recognized however with this little shark caught swimming above the sandy seafloor and coming for a more in-depth inspection of the bait container close to the digicam, it appears at the very least some females could also be utilizing Cocos Island as a parturition web site. With over 400 BRUVS deployments made across the Cocos Island throughout a variety of habitats since 2016, this being the primary sighting of a possible neonate may be very thrilling.
How have been the scientists positive this particular person was a child shark? Not solely was its measurement a very good indication, nevertheless it additionally exhibited physique options beforehand reported in neonates of this species reminiscent of a “conical head and a slender physique type, with a disproportionate caudal fin with the higher lobe considerably bigger than the decrease lobe and a low thrust angle.” Seeing a small shark in such a distant place isn’t extraordinary, as pregnant feminine tiger sharks and neonates have additionally been reported at different predator-dominated distant (>500 km) oceanic islands reminiscent of Hawaii and Galápagos. Despite the fact that Cocos is small in comparison with these two islands, it might nonetheless supply enough meals provide and quite a lot of habitats that this species requires for copy and long-term survival. Figuring out a nursery for this near-threatened species could be enormous, having vital implications for his or her conservation.
However there could also be a darker, various speculation to clarify the presence of this attainable child shark. It’s attainable a pregnant feminine captured close to Cocos Island could have aborted her pups whereas hooked, as has been seen for varied different elasmobranch species. Sadly, fishing continues to be thought of the principle menace affecting this distant and remoted no-take marine reserve … and this statement could also be simply probability. Sadly, proper now we don’t know which speculation is appropriate.
To higher perceive the reproductive ecology these sharks at Cocos Island, the authors counsel “combining the long-term shark monitoring program(s) with different non-lethal instruments reminiscent of acoustic/satellite tv for pc telemetry, [and] using transportable ultrasound tools or blood chemistry [to] quantify [tiger shark] reproductive cycles (migratory routes, parturition websites, residence vary, and so on.).” Hopefully, whether it is discovered that this can be a habitat that younger tiger sharks use, it may be correctly managed within the close to future.