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David Drennan

At the Fourth Latin American Aquaculture Congress and Exhibition (Panama, October 2000), I interviewed David Drennan, a shrimp aquaculture specialist, at the time head-quartered in Panama.  He is currently managing a shrimp hatchery in the Dominican Republic and living in Lecanto, Florida.


Drennan owns many firsts in shrimp farming.  Just to peak your interest, in May 1973, he was the first person to spawn Penaeus vannamei!


Shrimp News: How did you get into shrimp farming?


David Drennan: In 1967, after graduating from the University of Miami, while I was taking some postgraduate courses, I got involved with the Turkey Point Shrimp Project.  Turkey Point was the nuclear power plant that produced Miami’s electricity.  It wanted to use the warm water from the cooling towers to farm shrimp (P. duorarum).  During one growout trial, a cold front came through and the shrimp burrowed 5–6 inches into the mud bottom.  For the next two months, whenever the weather warmed up, a few more shrimp would pop up from the bottom.


One of my classmates, Yoshi Hirono (currently a shrimp farming consultant) was also working at Turkey Point.  It was an interesting project, and I easily became immersed in it.  With the guidance of Drs. Claire Idyll, Durbin Tab and Ed Iverson, we captured wild duorarum, stocked them in ponds and tested them as growout candidates.  During this period, my father, Dr. L. M. Drennan, who worked as medical director for Chiquita Banana, gave me the inside track on a shrimp farming job in Honduras, a joint venture between Chiquita and Armour Co.  Jerry Broom, formerly with the Louisiana Department of Wildlife and Fisheries, was hired to manage the project, and I took a job working for Jerry, as a liaison between the project and Chiquita.  Eric Heald, a Ph.D. from the University of Miami, was also on the staff.  Harold Weber, a consultant for Groton Associates and a good friend of Jerry and Eric, more or less brokered the project.


I grew up in the tropics, spoke Spanish and had previously lived in Honduras, so it was great fun pulling this project together—and all the while becoming increasingly fascinated by shrimp.


The project got rolling in late 1968, in Tulian, on Honduras’s Atlantic coast.  But by 1970 it was up for sale because Chiquita and Armour were taken over by companies that did not want to face the high development costs of a new industry like shrimp farming.  During the two years of operations, we worked mainly with white shrimp (setiferous) from Florida and some brown shrimp (aztecus) that we got from Harvey Persyn (currently chief executive officer of Tropical Mariculture Technology, a shrimp farming consulting company), who at the time was working for Dow Chemical in Texas.


Since I had also lived in Panama, I volunteered to go to the Pacific Coast of Panama to source shrimp species that might be right for farming in Honduras.  I made two sourcing (fishing) trips to Panama, one with Eric Heald and one by myself.  I shipped some gravid occidentalis to the Turkey Point Hatchery, which spawned them and shipped the postlarvae to Honduras.  Not many shrimp survived, but those that did grew incredibly fast.  We stocked them in February 1969.  Some reached 27 grams in less than 50 days.  By summer, they reached 100 grams.  They spawned naturally in the ponds, and I hatched the eggs in a small makeshift lab.  As the nauplii molted through their five stages, I made drawings.


I knew that Yoshi Hirono had just gone to work for Ralston Purina in Crystal River, Florida, and that Purina might be interested in purchasing the Chiquita/Armour project.  Yoshi came down to Honduras with Ralston Purina’s Dennis Zensen to appraise the farm.  Purina decided not to buy the project, but after seeing my drawings of occidentalis larvae and listening to me talk about the potential of shrimp farming, they offered me a job.  I had “hands on experience”, which Purina valued.  I accepted the job in 1971, sealing my fate in shrimp farming for the next thirty years.


Bill More, project director at Purina’s Crystal River, Florida, shrimp research facility, asked me if I wanted to work in Crystal River.  I told him that I thought Panama would be a better spot for me because I knew the area—and I knew how to set up a sourcing program for female shrimp there.  The growth of the occidentalis in Honduras had really bedazzled me!


For two and a half years I was Purina’s man in Panama.  At the time nobody knew much about penaeid shrimp on the Pacific Coast of Central and South America.  I sourced shrimp there from February 1972 to late 1973.  Early on, I could not determine if the females (occidentalis) had mated or not.  Then one day, I detected a small blob of crystal-colored gel next to a female’s thelycum (genitalia).  Hmmmm….  It turned out to be the remnants of a spermatophore.  Now, finally, I knew what to look for, females with attached spermatophores, or parts of spermatophores.  They had mated.  They were the ones that produced fertile eggs.


My first work was with occidentalis, which accounts for around 85% of the commercial catch of white shrimp off the Pacific Coast of Panama.  Stylirostris accounts for 12%–15% and vannamei for 1–3%.  One of the top guys at Purina called me “the shrimp hunter”.  He was right, I loved hunting gravid female shrimp on the open seas at night.


I kept them from spawning by lowering the water temperature in their tanks to about 18ºC.  Then, I would pack them up and put them on an early morning flight that arrived at the Crystal River, Florida, hatchery at 4 p.m.  I was putting in 16-hour days, but it was easy work for me—I was driven.


Most of the females aborted during the flight to Miami.  I needed to develop a better system.  I tried shipping the eggs, but that didn’t work.  Finally, after a lot of trial and error, I discovered that shipping nauplii (the first larval stage after hatching from the egg) worked best.  I put the nauplii (stage-3) in oxygenated, double plastic bags and then packed the bags in styrofoam boxes for shipment.  I set up a little spawning area at the Smithsonian’s Research Station on the Naos Island, where I hatched the eggs and collected the nauplii.  That was at the beginning of 1973.  I was Purina’s one man show in Panama, politician, businessman, biologist—and hunter.  By this time, the beginning of 1973, shrimp farming was in my blood, a lifetime infirmity, I fear.


The Smithsonian’s Dr. Ira Rubinoff graciously provided me with a fiberglass-over-cardboard building to serve as a temporary lab.


One night, I was shrimping in a new area and caught a female Penaeus vannamei—with a spermatophore attached!  I had captured males and females of this species before, but this was my first mated female.  Knowing that she was different, I kept her in a separate tank, spawned her, hatched the eggs and sent the nauplii to Purina’s hatchery in Crystal River, Florida.  These nauplii were different from other penaeids; they had a small red dot right in the center of the embryo.


Of the 250,000 naups that survived the trip, Bill More and Harvey Persyn stocked 75,000 postlarvae in a half-acre pond and sent 75,000 to Jack Parker at the Texas Mariculture Station in Palacios, Texas.  He stocked them in a half-acre pond, too.  Early on, in Florida, the growth was great, about a gram a week, but no one paid much attention to them.


In Texas, Jack was doing a little demonstration harvest for a bunch of Fish and Wildlife officials, and to everyone’s amazement, he pulled 2,000 pounds of shrimp out of the half-acre pond.  And lo and behold—the same thing happened in Florida, a harvest of over 2,000 pounds from a half-acre pond, on the first try.  We were off to the “shrimp races”.


I had to source more vannameiVannamei makes up such a small percentage of the penaeids off Panama that I didn’t recognize them the first time I saw their distinctive white legs (patiblancos).  I had to go to the Smithsonian’s library in Panama to identify them.  Eventually we discovered the best places, seasons and hours to fish them.  Sometimes they were as scarce as hen’s teeth.


In early 1973, I started looking for farm sites in Panama.  I found a large salt flat on the Gulf of Parita that I thought would be a good location for a shrimp farm because there were no mangroves or trees on it, and the area was not being used for anything else.  The clearing cost would be negligible.  So I flew over the site, took some pictures and sent them up to Crystal River, where they mulled over things for awhile and then came down to have a look.  Everyone agreed that it was a great site for a shrimp farm.  In 1974 we started Agromarina de Panama, S.A., with a 12-acre pilot farm in Aguadulce.  Everyone also agreed that we needed a hatchery, so, also in 1974, we started a hatchery in Veracruz.  My job was sourcing females and helping with the hatchery.


Bill More was general manager; Ron Staha, hatchery manager; and Padge Beasley, farm manager.  Initially, we farmed stylirostris, with good results the first year, but the next year, 1975, we got hit with IHHNV, a viral disease that causes very high mortalities in stylirostris.  It killed 89% of the juveniles in the nursery ponds.  Vannamei were more resistant, but did show numerous deformities from the virus.  Since vannamei became our prime candidate for culture, we knew we would have to start breeding them.  Soooo…we put some adult vannamei in maturation tanks and observed their behavior.  The males would pursue the females, but matings seldomly occurred because most of the females were very slow mature.


About this time, Joe Mountain (Pepe) was hired, and it was Joe who came up with the idea of pinching off one eyestalk (glands in the eyes produce a hormone that inhibits egg production in penaeid shrimp).  This caused the females to mature when we fed them marine worms (polychaetes, bloodworms, natural foods for wild shrimp).  We fed worms, squid and Purina’s dry MR-25 diet to the shrimp and lo and behold, the females started to develop eggs.  Better yet, we started to get matings, but not all the time.  At one point to get their juices flowing, I collected spermatophores from wild-caught occidentalis and stylirostris, mashed them all together, and threw them into the vannamei maturation tanks.  Sometimes this excited the males so much that they would miss the female’s thelycum and attach their spermatophores to their legs, heads and bodies—and even to each other.


We brought penaeid maturation under control in 1976, primarily out of necessity, because vannamei were so difficult to find in the wild.  Agromarina de Panama, which changed hands and names in 2001, nurtured some great shrimp farmers.  Here I would like to recognize some of my fellow workers: Bill More, Peter Van Wyk, Glen Bieber, Joe Mountain, Harvey and Amber Persyn, Yoshi Hirono, Frank Follet, Padge Beasley, Ron Staha, Billy Durmond, Rolland Laramore, Durwood Dugger, Ron Wulff, Bill MacGrath, Reggie Markam, Randy Aungst, Franklin Kaiwben, Freddy Cherigo, N.G. Ovidio and Gonzalo Sanchez.  We were blessed because Ralston Purina was willing to do the project right, which gave us the opportunity to bring together the talent.  Later, Ron Staha and Yoshi Hirono left the project, and in 1980, I became the hatchery manager in Veracruz.  I have always enjoyed designing and working in shrimp laboratories.


One of my most memorable sourcing trips was with Dr. Isabel Farfante, a distinguished shrimp researcher and coauthor of Penaeoid and Sergestoid Shrimps and Prawns of the World (Keys and Diagnoses for the Families and Genera).  She was interested in sourcing and collecting specimens to illustrate the reproductive system of penaeid shrimp.  On the night that she accompanied me on a sourcing expedition, we collected vannamei, stylirostris, occidentalis and one californiensis, which was still soft from molting and carried a spermatophore plug.  When she was working on the deck it was hard to imagine she was in her sixties.  In appreciation, she sent me a copy of her original drawing of stylirostris’s reproductive system.


I left Agromarina in 1990.  In 1991, I did some consulting for Zeigler Bros., a shrimp feed manufacturing company in Pennsylvania, and then went to work for Zeigler full-time.  Basically, my job was to help Zeigler make better shrimp feeds.  Zeigler has always been receptive to my suggestions and is committed to shrimp nutrition from the womb to the tomb.


I was also involved in the inception and start-up of Belize Aquaculture, Ltd., a high-tech, zero-exchange, super-intensive shrimp farm.  I designed the pilot hatchery and recirculating maturation facility and helped with the broodstock program.  We were the first hatchery to close the breeding cycle for SPF vannamei in Belize.


Recently, I successfully completed work on the design of a broodsock rearing facility at Farallon Aquaculture in Panama capable of producing up to 40,000 broodstock a year.  The goal at this facility is to develope shrimp with fast growth, fecundity and disease resistance.


Information David Drennan, 71 North Youngtree Point, Lecanto, Florida 34461 (phone 1-352-249-7039, email banidpd@yahoo.com).


Source: David Drennan, Interviewed by Bob Rosenberry, Shrimp News International, in October 2000 in Panama City, Panama. Published on October 4, 2002.


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