B_&_T_J_2015_

The Puzzle of Regional Proportions

Bonefish & Tarpon Genetics

One of the questions by anglers fishing

for tarpon has been: “Are our fish also their

fish?” In other words, are the populations of

tarpon in one location connected to tarpon

in other locations, and how should this

influence conservation? A longstanding

question for BTT, this remains a valid and

important question for tarpon conservation.

But it is only part of a larger issue that applies

to bonefish and permit as

well—to what extent is

conservation local vs

regional?

That original query

focused on adults and

whether they were

capable of long-distance

migrations that

connected fisheries in

different locations.

Indeed, the satellite

tagging data show that

some tarpon do

undertake long-

distance, seasonal

migrations, and as such are potentially part of fisheries in

different locations. But migration by adults is only one way

that fish populations can be connected. Fish populations

can also be connected by the transport of larvae by ocean

currents, which brings bonefish and permit into the mix.

We know that bonefish, tarpon, and permit spawn in deep

waters far from their flats habitats. Tarpon spawn offshore

near full and new moons during summer. Bonefish spawn off

of deep drop-offs at night during full and new moons during

winter. Permit spawn near reef promontories or artificial

reefs, with peak spawning during late spring and summer.

In all cases these species follow a strategy of reproduction

called “broadcast spawning”, a technique whereby large

schools of mixed males and females eject (broadcast) their

eggs and sperm into the open water, the eggs are fertilized,

and once hatched the larvae float in the open ocean for

weeks (the exact length of time depends on the species).

These larvae might circle around in an ocean gyre that

delivers them back to near where their parents’ live, or

might carry them long distances away from that location.

By virtue of the fact that some larvae are delivered back to

their parents’ location, the population could be considered

“self-supporting”. The extent that larvae are transported to

other locations reflects the amount of “connectivity” among

local populations.

The goal of the Bonefish and Tarpon Population Genetics

Programs is to determine how much bonefish and tarpon

populations are connected vs self-supported. (A permit

population genetics project will begin in the future.) The

Genetics Programs will work this way: anglers and guides

will collect fin clips from bonefish and scales from tarpon

using kits provided by BTT; they will then send the samples

to BTT, and we will work with collaborating genetic

scientists to analyze the samples to determine the level

of connectivity among bonefish and tarpon populations

throughout the region. If we successfully collect enough

genetic samples from enough places, we will have a

better idea of the mix of local and regional conservation

that is needed.

The challenge is collecting enough genetic samples from

throughout the geographic ranges of bonefish and tarpon in

the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico. This

is where you come in. If you fish for bonefish and tarpon, we

need your help. We are asking anglers and guides to collect

fin clips from bonefish and scales from tarpon. We use the

skin from the fins and from the scales for genetic analysis.

You can make a difference.

D R. A A R O N J. A D A M S

is Director of Operations for Bonefish & Tarpon Trust

Photos by Dr. Aaron J. Adams

Bonefish fin clip kit.

Todd Fuller, of Hell’s

Bay Boatworks,

holds a tarpon scale.