Importance of Natural Resources

How saving coastal ecosystems will save the Black Sea Bass | UNC-TV Science


>>IAN KROLL IS GOING FISHING.>>PRETTY EASY TO CATCH. YOU CAN JUST DROP A LINE IN WITH
SOME SQUID OR SHRIMP AND PULL THEM UP.>>AT LEAST HE HOPES THEY’RE
EASY TO CATCH.>>SO THEY LIVE CLOSELY
ASSOCIATED WITH THE BOTTOM. THEY’RE REALLY DRAWN TO
STRUCTURES LIKE OYSTER REEFS, WHICH WE’LL FIND ON THE BOTTOM. THEY LIKE PILINGS LIKE THESE. THEY ALSO LIKE CONCRETE
STRUCTURES OR JETTIES. IT OFFERS THEM A BIT OF
STRUCTURE AND PROTECTION FROM PREDATORS. YOU WANT TO LET IT SIT ON THE
BOTTOM BUT — GOTCHA!>>KROLL IS FISHING FOR THESE,
BLACK SEA BASS, BUT HE ISN’T FISHING FOR DINNER. HE’S FISHING FOR RESEARCH.>>WHAT I’M LOOKING AT ARE HOW
DIFFERENT HABITATS SUPPORT AN ADULT POPULATION. AS I WAS SAYING, BLACK SEA BASS
IS REALLY IMPORTANT TO THE ECONOMY, SO WHAT WE WANT TO KNOW
IS HOW CAN WE PRODUCE MORE OF THEM OR CONTINUE PRODUCING THEM
AT A LEVEL THAT WE NEED THEM. AND IN ORDER TO DO THAT, WE NEED
TO LOOK AT THEIR JUVENILE OR YOUNG STAGE.>>BLACK SEA BASS SPAWN IN THE
OCEAN, BUT THEN THE LARVAE DRIFT AND SWIM INTO THE ESTUARIES,
WHERE THEY FIND FOOD AND SHELTER. IT’S A GOOD PLACE TO GROW UP. THEY STAY THROUGH THE SPRING AND
SUMMER BUT THEN RETURN TO THE OCEAN IN THE FALL.>>SO WHAT I’M LOOKING AT ARE
TWO DIFFERENT TYPES OF HABITATS, INSHORE ESTUARINE HABITATS,
LIKE WE’RE IN RIGHT NOW IN BOGUE SOUND, AND THEN OFFSHORE
HABITATS. TRADITIONALLY, WE USED TO THINK
THAT ALL OF THE FISH WOULD MOVE INSHORE, ALL THE YOUNG FISH
WOULD MOVE INSHORE TO GROW UP. HOWEVER, WE’VE BEEN SEEING MORE
AND MORE THAT WE’RE FINDING THESE YOUNG FISH OFFSHORE IN
HABITATS LIKE ARTIFICIAL REEFS, SUNKEN SHIPS, OR EVEN NATURAL
REEFS. SO WHAT I’M TRYING TO LOOK AT IS
WHETHER A CERTAIN HABITAT CAN CONVEY BENEFITS THAT THE FISH
CAN THEN CARRY ON WITH IT. SO IF ONE FISH GROWS UP IN AN
ESTUARY THAT OFFERS THEM A LITTLE MORE PROTECTION OR A
HIGHER SURVIVAL RATE, MAYBE MORE FOOD, THEY CAN GROW QUICKER AND
MATURE QUICKER VERSUS AN OFFSHORE HABITAT THAT MIGHT BE A
LITTLE MORE EXPOSED, THEN THAT WILL ULTIMATELY AFFECT THE FATE
OF THE FISH AND ON A LARGER SCALE THE FATE OF THE
POPULATION. I’LL TAKE A COUPLE OF THEM OUT
OF THERE.>>THE TROUBLE IS, FISH AREN’T
EASY TO TRACK. THEY’RE HARD TO SEE,
HARD TO FOLLOW. THE OCEAN IS LARGE. BUT IT TURNS OUT FISH HAVE A
KIND OF FLIGHT DATA RECORDER BUILT INTO THEM. IT’S CALLED AN OTOLITH. IT’S A TYPE OF EAR BONE.>>THE OTOLITH GROWS LIKE A TREE
WITH RINGS, SO YOU CAN LOOK AT DIFFERENT AGES OF THAT
INDIVIDUAL. AND THEN BASED UPON THE
CHEMISTRY THAT’S INCORPORATED INTO THOSE RINGS, YOU CAN TRY TO
INFER IF THAT FISH GREW UP IN FRESHER WATER OR SALTIER WATER
OR WATER TO THE NORTH OR WATER TO THE SOUTH. AND, THEREFORE, WE HAVE THIS
SORT OF — THIS INDIVIDUALIZED RECORD OF EACH INDIVIDUAL FISH’S
MOVEMENTS THROUGH SPACE AND TIME.>>THE OTOLITH BONE STRUCTURE IS
EXTREMELY DELICATE. THE TINY BONE SITS JUST BEHIND
THE BRAIN. AND ONCE IT’S REMOVED, IF YOU
LOOK CLOSELY, YOU CAN SEE AND COUNT THE RINGS. THOSE RINGS TELL THE PRECISE AGE
OF THE FISH. ANALYZING THE BONE CHEMISTRY
TELLS WHERE THE FISH HAVE LIVED. IT’S FAIRLY NEW SCIENCE. BUT BY COLLECTING OTOLITHS FROM
JUVENILE BLACK SEA BASS IN ESTUARIES AND ADULTS OFFSHORE,
RESEARCHERS HOPE TO BUILD AN ATLAS OF BLACK SEA BASS
POPULATIONS.>>IT’S GOING TO TELL US WHERE
DID THESE FISH GROW UP, AND THAT GETS AT THE QUESTION OF WHICH
HABITATS ARE PROVIDING THE LARGE AMOUNT OF STOCK THAT WE SEE
OFFSHORE, WHICH HABITATS ARE MORE SUCCESSFUL IN GETTING FISH
PAST THESE JUVENILE STAGES AND HAVING THEM BECOME REPRODUCTIVE
MEMBERS OF THE ADULT POPULATION.>>THAT KNOWLEDGE SHOULD HELP
GUIDE HABITAT PROTECTION. THAT’S AN IMPORTANT FACTOR IN
PRESERVING THE ROUGHLY $1.4 MILLION COMMERCIAL AND
RECREATIONAL BLACK SEA BASS FISHERY.>>THAT EXTENDS, THEN,
INTO CONSERVATION, AND THAT’S KIND OF THE BIGGEST EXTENSION OF
THIS PROJECT, IS LOOKING AT WHICH HABITATS DO WE RELY ON TO
PROVIDE US WITH THIS COMMERCIALLY, RECREATIONALLY,
ECONOMICALLY IMPORTANT SPECIES. THE WHOLE DISCOVERY OF OTOLITHS
AND WHAT THEY MEAN AND WHAT THEY CAN BE USED TO LEARN ABOUT THE
FISH AND THE POPULATIONS AS A WHOLE IS INCREDIBLE. IT’S KIND OF — IT’S LET US
LEARN SO MUCH MORE ABOUT WHAT’S GOING ON IN THE OCEAN. YOU LOOK AT THIS FISH, AND I CAN
TELL YOU ITS SIZE, AND I CAN TELL YOU MAYBE WHETHER IT’S MALE
OR FEMALE. BUT THEN YOU LOOK AT THIS
OTOLITH, AND YOU CAN SEE, OKAY, I CAN TELL YOU AN AGE OF IT
PRECISELY. I CAN TELL YOU WHERE IT’S BEEN,
AND PERHAPS WE CAN LOOK AT MIGRATION.


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