Seas of life 3

MOST OF THE FISH HERE ARE PERMANANET RESIDENTS, FEEDING ON PLANKTON, THE TINY FLOATING PLANTS AND ANIMALS THAT ARE NOURISHED BY THE RICHNESS BROUGHT UP FROM THE DEPTHS.
AND THEY IN TURN, ATTRACT VISITORS FROM THE OPEN OCEAN………. TUNA….
THE PLANKTON FEEDERS ARE EASY TARGETS. ALL THIS ACTION ATTRACTS EVEN LARGER PREDATORS.
SHARKS… HUNDREDS OF SHARKS.
SILKY SHARKS ARE NORMALLY OCEANGOING SPECIES. BUT SEA MOUNTS IN THE EASTERN PACIFIC , LIKE COCOS, MALPELO, AND THE GALAPAGOS, ATTRACT SILKIES IN HUGE GROUPS UP TO 500 STRONG.
SILKIES SEEM TO SPECIALIZE IN TAKING INJURED FISH AND CONSTANTLY CIRCLE SEA MOUNTS ON THE LOOKOUT FOR THE CHANCE TO DO SO. BUT SILKIES ARE NOT THE ONLY VISITORS.
HAMMER HEADS GATHER IN SOME OF THE LARGEST SHARK SHOALS TO BE FOUND ANYWHERE IN THE OCEAN.
SOMETIMES THOUSANDS WILL CIRCLE OVER A SINGLE SEA MOUNT.
BUT THESE SHARKS ARE NOT HERE FOR FOOD. THEY HAVE COME FOR ANOTHER REASON. SOME OF THE LOCALS
PROVIDE A CLEANING SERVICE. FOLLOWING THE LAST EL NINO YEAR, WHEN A RISE IN WATER TEMPERATURES CAUSED MANY SHARKS TO SUFFER FROM FUNGAL INFECTION. THE NUMBER OF HAMMERHEADS VISITING THE SEA MOUNTS REACHED RECORD LEVELS.
NUTRIENTS ALSO WELL UP TO THE SURFACE ALONG THE COAST OF THE CONTINENTS.
THIS IS NATAL, ON SOUTH AFRICA’S EASTERN SEABOARD. IT’S JUNE, AND JUST OFFSHORE, STRANGE BLACK PATCHES HAVE APPEARED.
THEY LOOK LIKE IMMENSE OIL SLICKS UP TO A MILE LONG, BUT THIS IS A LIVING SLICK. MILLIONS AND MILLIONS SARDINES ON A MARINE MIGRATION THAT, IN TERMS OF SHEER BIOMASS, RIVALS THAT OF THE WILDEBEAST ON
GRASSLAND OF AFRICA.
THESE FISH LIVE FOR MOST OF THE TIME IN THE COLD WATERS SOUTH OF THE CAPE. BUT EACH YEAR, THE COASTAL CURRENTS REVERSE. THE WARM AGHULAS CURRENT THAT USUALLY FLOWS DOWN FROM THE NORTH HAS BEEN DISPLACED BY THE COLD WATER COMING UP FROM THE SOUTH, AND THAT HAS BROUGHT UP RICH NUTRIENTS. THEY, IN TURN, HAVE CREATED A BLOOM OF PLANCTON, AND THE SARDINES ARE NOW FEASTING ON IT. AS THE SARDINES TRAVEL NORTH, A WHOLE CARAVAN OF PREDATORS FOLLOW THEM. THOUSANDS OF CAPE GANNETS TRACK THE SARDINES. THEY NESTLED OFF THE CAPE AND TIMED THEIR BREEDING SO THAT THEIR NEWLY FLEDGED CHICKS CAN JOIN THEM IN PURSUING THE SHOALS.
BELLOW WATER, HUNDREDS OF SHARKS HAVE ALSO JOINED THE CARAVAN. THESE ARE BRONZE WHALER SHARKS,
A COLD-WATER SPECIES THAT NORMALLY LIVES MUCH FURTHER SOUTH,