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Handling Offshore Catch on Board
HANDLING
OFFSHORE CATCH ON BOARD
by Jon W. Bell
Offshore
fishing in the Gulf of Mexico can require a good deal of effort
and resources from the Louisiana sports fisherman. However,
the rewards of hooking and bringing on board a highly prized
fish such as tuna, amberjack, mahi mahi, marlin, and others
are greatly increased by the superior eating quality of the
meat. Proper onboard handling practices are important for
maintaining the good eating quality critical to producing
excellent, “just-caught” flavor.
Decomposition
or spoilage of fish is caused by breakdown of the flesh by
naturally occurring enzymes or bacteria. The rate or speed
of decomposition is increased by high temperatures, similar
to those encountered during prolonged struggle in warm Gulf
waters.
Controlling
and maintaining good quality of the fish requires proper chilling.
Taking enough ice to chill and store the catch is a MUST to
prolong good quality. No matter how you handle the fish, you
must properly chill and store the fish to control decomposition
and quality loss. Two pounds of ice for each pound
of fish is recommended for icing and storage. Line
the bottom of the cooler with a layer of ice, and then surround
the entire fish with more ice.
Additional
recommended handling practices accomplished before iced storage
can delay the loss of freshness and quality and produce meat
of high, “sushi”, quality.
- Landing
—Bring the fish on board as quickly as possible.
Gaff the fish in the head, or the tail region if necessary.
- Stunning
— Stun the fish immediately
after it comes on board to eliminate bruising. It is best
to club the fish with a metal bar or wooden bat while the
fish is still on the gaff.
- Brain
Spiking — Spiking, immediately
after stunning, is an option that destroys the fish’s
brain. (This is a required procedure for production of commercial,
sashimi grade tuna). Spiking can significantly reduce the
rate of early chemical decomposition in the muscle. Before
spiking a fish, make sure that you are well balanced and have
a firm grip on the fish. Place the tip of the spiking tool
(I prefer a ground-down philips screwdriver, but an ice pick
will also work) on the soft spot of the fish’s head
above the eyes. Push the spike at a 30 degree angle into the
skull, and move from side to side to destroy the brain. Successful
spiking will cause the fish to shudder, muscles to flex, and
then go limp in a couple of seconds. This may require some
practice, and may not be possible under all conditions. Above
all, be careful not to injure yourself or fellow anglers!
- Bleeding
— Bleeding improves the muscle
appearance and flavor and may aid in rapid chilling. It is
also essential for sashimi grade fish. Bleed the fish on the
deck, immediately after stunning or spiking, while the heart
is still intact and pumping. Use the method which seems easier
for you, or try a combination of cuts.
- Gill
Cut — Slice through the blood
vessels that supply oxygen to the gills. Lift the gill cover
and cut through the gill arch, and then put the knife through
the gill membrane and cut up towards the spine to sever the
blood vessels at the top of the gills.
-
Throat Cut — Cut the blood
vessels between the heart and gills. Be careful not to cut
up the heart. Slice through the V-shaped nape of flesh between
the gill covers and the body of the fish, and sever the major
artery that is just below the skin surface.
- Pectoral
Cut — (for tunas) Cut the
shallow blood vessels that run near the lateral line. Make
a shallow cut with a sharp knife about the width of two fingers
below the pectoral fin, cutting through the raised ridge of
the skin. You’ll know when you’ve done it right
when the blood flows out of the cut. Repeat on the other side.
- Gutting
— After allowing 5 – 10 minutes for
bleeding, or until blood flow stops, removing the guts or
viscera from the fish provides two advantages for maintaining
good quality. First, you remove a source of bacteria and enzymes.
Second, chilling is improved by removing a significant amount
of warm body weight, especially if the fish has been feeding.
Cut the belly from the anal opening forward, open the belly
cavity and remove the guts. To completely remove them, slice
the entrails as close as you can to the gill area. Be careful
not to slice through the belly wall and into the meat. This
technique will allow the chilling medium, either slush or
ice, to closely contact the muscle both inside and out. Be
sure to firmly pack ice into the belly cavity during iced
storage.
- Rapid
Chilling (Slush Icing) — Bring along an extra
cooler or use the boat’s bait tank if possible. This
extra effort may be the most important technique for retaining
the excellent, or “just- caught” quality of the
meat. Fish will cool 4 to 5 times faster in slush
ice because the fish will be completely surrounded
by the 32ºF slush water. This requires bringing extra
ice, above the amount for storing the fish. The recommendation
is for 2 parts ice to 1 part seawater, but
more may be necessary with the warm Gulf waters. Make sure
that ice is always present and covering the surface of the
slush. Add more ice as it melts. Transferring the fish to
iced storage is recommended when the fish reaches a backbone
temperature of 50ºF. For large fish, this can take up
to 8 hours, or even longer. However, even an hour or less
in the slush ice can dramactically lower the high, initial
fish temperature. Slush icing should not hurt properly gutted
fish. Transferring the fish to iced storage will depend on
when the next fish is caught, the amount of ice left on board,
time left before returning to shore, etc. Leaving fish in
the slush tank for over 2 hours is not recommended, except
for large fish.
Make
sure that you bring plenty of ice and coolers to preserve
good food quality of your catch. Performing some or all
of these additional recommended handling practices can produce
high quality, just-caught freshness for you and your friends
to enjoy once you return to shore!
References
Nakamura,
R.M., Akamine, J.S., Coleman, D.E.. and Takashima, S.N.
1987. The management of yellowfin tuna in the handline fishing
industry of Hawaii – a fish-handling handbook. Sea
Grant Advisory Report UNIHI-SEAGRANT-AR-88-01, University
of Hawaii Sea Grant College Program, Honolulu, HI.
Price,
R.J. 1989. Why seafood spoils. California Sea Grant Extension
Program, Publication UCSGEP 89-3, University of California,
Davis.
Price,
R.J. and Melvin, E.F. 1994. Recommendations for on board
handling of albacore tuna. California Sea Grant Extension
Program, Publication UCSGEP 94-4, University of California,
Davis.
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