Angler care when handling and releasing snook will dramatically
reduce the harmful effects of cryptic mortality.
Florida's resident population of 14.7 million increases daily by
about 1,200, and 40 million tourists visit the state annually.
Because of our robust fishery resources, fishing is a favorite
pastime of both residents and visitors. In 2001, marine
anglers made about 27.5 million trips, caught 145 million marine
fishes, and released 78 million of them. Even though fishery
resources are renewable and more than half of the total catch may
be released, future increases in the human population and the
accompanying increase in fishing mortality mandate that Florida's
fisheries be managed prudently to ensure long-term quality angling
for residents and visitors alike. Regulations can serve to maximize
stock abundance, but only anglers who practice proper
catch-and-release techniques can minimize the intrinsic loss of
marine fishes to 'cryptic mortality,' which refers to those
fishes that die unobserved after having been caught and
Dynamics of the snook fishery illustrate the magnitude and
consequences of these unseen losses and reveal why we need to
carefully release any snook that is caught but not destined for the
creel. A review of the statistics from the latest stock
assessment indicates that we are precipitously close to
a situation that has no palatable solution. On the Gulf coast, of
the 1.335 million snook that were caught, more than 97% of them -
1.299 million - were released. Of the total number of fish
harvested - 63.9 thousand - however, only 36.3 thousand were landed
or put in the cooler. What happened to the other 27.7 thousand
snook? How can that many fish be unaccounted for and how did
biologists arrive at that number? A controlled study conducted
within the fishery estimated the catch-and-release mortality rate
for snook to be 2.13%. Simply multiply the number of snook released
by .0213 (1.299 x .0213 = 27.7) and you arrive at the number of
snook that died after being released - fish that will never make it
to a cooler. Wasted!! In other words, 43% (27.6/63.9) of the total
number of snook harvested were lost to cryptic mortality.
Now, the total number of fish lost to cryptic mortality is an
estimate from a single iteration, which means that we assume a
single snook is caught only one time in the year. But what really
happens is not that simple.
Another look at the latest stock assessment describes what
really happened. The estimated number of snook in the total
population that are at least age 3 or about 20" total length is
329,000. Last year, anglers caught 1.335 million snook - far more
snook than are in the total population. If we divide the number of
snook caught by the number of snook in the estimated population
(1.335/329 = 4.06), we discover that each snook may have been
caught as many as 4 times each year. This means that in this
real-life situation, the real loss to improperly dehooking and
releasing snook was not the 2.13% previously estimated, but was in
fact much higher: the percentage of snook 'wasted' to cryptic
mortality in this example was greater than the estimated 43%.
The real loss is not well understood because we don't know how many
snook less than 20 inches are caught and released, but it is fair
odds that perhaps half of the total harvest of snook die each year
from that unseen but pervasive problem of cryptic
What can anglers do to reduce the number of deaths due to cryptic
mortality? You've heard it before and it has become a litany - be
as careful as possible when releasing any snook! Practice proper
catch-and-release techniques! So what are the proper techniques for
dehooking and returning snook, or any fish for that matter? What
follow are guidelines, not rules, but remember that the future of
our fish stocks depends in part on how carefully and closely we
- "Limit your kill, don't kill your limit!" Perhaps
the most important guideline!
Decide beforehand which fish are to be kept and immediately
release all others.
- Hook and land as quickly as possible fish you want to bring
onboard for a short time and then release- extended struggle may
lead to the fish's death.
- Try barbless or circle hooks. Catch rates increase, and
physical damage decreases.
- Avoid the use of gaffs or 'hard' landing nets.
- Leave the snook in the water, if possible, while dehooking
- Cut the leader close if the fish is gut-hooked or if the hook
is difficult to remove.
- Wet your hands or gloves to handle fish. Remove as little slime
- Control the fish as best you can. Dropping the fish could kill
- Use a dehooking tool if the hook is deep in the mouth.
- Do not hold large fish vertically by the lower jaw. In a study,
50 of 50 barramundi (a related species) died after being held this
- If your fish is in good shape, release it immediately back to
the water head first. If it is exhausted, attempt to revive
it. Move the fish into the shade, either alongside the
boat, under the edge of a dock, or to the bottom. Cooler water
contains more oxygen. If the fish is in good shape, merely hold it
headfirst into the current. If it is severely lethargic, hold the
bottom jaw agape and gently move the fish forward. No back and
forth movements! (Have you ever seen a fish swim backwards?)
Severely exhausted fish may require several minutes to
revive. At the first sign of attempting to swim
away, let it go! Some fish will swim a short distance,
become disoriented, sink to the bottom and die, snook especially,
so be observant.
- If your fish dies despite your best efforts, you can add it to
your creel if it meets all regulations. Otherwise, discard it.
A closely related and highly debated subject concerns the
effects of catching and releasing snook during the spawning season.
Should we fish for snook while they are reproductively
active? We conducted extensive research on the spawning
aggregations in Jupiter and Lake Worth inlets during the summer of
1988 and 1999. Individual aggregations containing several thousand
adult snook were monitored consistently from June until early
September. One hundred and forty large spawning female snook
were caught on hook and line, tagged with a visible external tag,
and released back into the inlet where they were captured and
tagged. Five of these fish were implanted with
acoustical transmitters. These five fish were then observed
by divers and manually tracked with acoustic hydrophones.
Periodically, a total of 50 of the tagged females were speared,
sacrificed, and their ovaries fixed for histological observation.
The time between capture and recapture ranged from 1 to 73 days.
Each ovary, regardless of time lapsed after being hooked and
released, showed evidence of either immediate past spawning
(contained postovulatory follicles) or indications of imminent
spawning (hydrated oocytes). These results show that reproductive
snook are capable of spawning after being caught and released. We
can't yet determine if hooking episodes reduce the quality or
quantity of the gametes, but we do know that reproductive snook
continue to spawn uninterrupted, despite being caught with hook and
line and released. However, for obvious reasons, we should be
doubly diligent in using proper catch-and-release techniques when
fishing for large reproductive snook; in doing so, we will not only
preserve the female, but also ensure the survival of her progeny.
Hopefully, what many anglers practice - voluntarily choosing not to
fish for snook during the summer spawning season - will not become
a rule. If proper catch-and-release techniques are used, this
practice is unnecessary; however, the ethic is commendable.