Alligator (Alligator mississippiensis) Aquaculture in the United States - Regulations.gov
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REVIEWS IN FISHERIES SCIENCE & AQUACULTURE
2018, VOL. 26, NO. 1, 86–98
https://doi.org/10.1080/23308249.2017.1355350
Alligator (Alligator mississippiensis) Aquaculture in the United States
Mary J. Nickuma, Michael Masserb, Robert Reighc, and John G. Nickumd
a
All Things Editorial, Fountain Hills, Arizona, USA; bTX A&M University, College Station, Texas, USA; cAquaculture Research Station, Louisiana
State University Agricultural Center, Baton Rouge, Louisiana, USA; dNickum & Nickum, Inc., Fountain Hills, Arizona, USA
ABSTRACT KEYWORDS
Commercial production of American alligator (Alligator mississippiensis) under intensive aquaculture American alligator; alligator
conditions began in the 1980s. During the last 30 years, alligator farming has become an mississippiensis; aquaculture
aquacultural industry worth millions of dollars in the southern United States. In 2014, farmers in
Louisiana, the nation’s largest producer of captive-reared alligators, sold more than 383,000 skins
valued at more than $77 million. Most alligator farming operations utilize wild-sourced eggs, which
are collected from wetland habitats under the authority of permits issued by State agencies.
Typically, these permits include a requirement to return a portion of farm-reared animals to the
same area where eggs were collected to maintain wild populations. Intensive rearing of alligators
requires an abundance of warm water and good quality food. Extruded feeds formulated
specifically for alligator are the industry standard in modern production systems. Disease can be an
occasional problem in alligator production operations but risks can be minimized with provision of
clean water, high-quality feed, and good hygienic conditions in grow-out facilities. Belly skins are
the primary product of alligator aquaculture, but alligator meat is also sold in niche markets.
Although products made from alligator skins have strong consumer appeal, the relatively high cost
of products made with alligator leather limits sales to more affluent consumers. Growth of alligator
farming, using current production methods, will be limited by the natural productivity of the wild
resource upon which the industry depends and demand for products utilizing alligator leather.
From 2004 to 2013, global demand for skins of all species of crocodilians averaged 1.4 million skins
annually, of which 24.3% were American alligator.
Introduction
role as ecosystem engineers in wetland ecosystems
The American alligator (Alligator mississippiensis) some- through the creation of alligator holes, which provide
times referred to colloquially as a gator or common alli- wet and dry habitats for other organisms.
gator, is a large crocodilian reptile endemic to the The American alligator is listed as ‘Least Concern’ by
southeastern United States. It is one of two living species the International Union for Conservation of Nature
in the genus Alligator within the family Alligatoridae (IUCN). Historically, hunting had decimated their popu-
and it is larger than the other extant alligator species, the lation. Subsequent conservation efforts have allowed
Chinese alligator. Adult male American alligators mea- their numbers to increase and the species was removed
sure up to 3.4 to 4.6 m in length and can weigh up to 453 from the list in 1987. Alligators are now harvested for
kg. Females are smaller, measuring around 3 m. The their skins and meat.
American alligator inhabits freshwater wetlands, such as Though not truly domesticated, alligators and croco-
marshes and cypress swamps from Texas to North Caro- diles have been bred in farms since at least the early 20th
lina. It is distinguished from the sympatric American century; however, the vast majority of these early busi-
crocodile (Crocodylus acutus) by its broader snout, with nesses were farms in name only, primarily keeping alliga-
overlapping jaws and darker coloration. It is less tolerant tors and crocodiles as a tourist attraction (Anonymous,
of saltwater, but more tolerant of cooler climates than 2014). The St. Augustine Alligator Farm Zoological Park,
the American crocodile, which is found only in tropical established in 1893, was a prime example of this early
climates. type of alligator farm. Only in the 1960s did commercial
Alligators are apex predators and consume fish, operations that either harvested eggs from the wild or
amphibians, reptiles, birds, and mammals. Hatchlings bred alligators on-site begin to appear (Medley, 1970).
feed mostly on invertebrates. They play an important This was largely driven by diminishing stocks of wild
CONTACT Mary J. Nickum mjnickum@hotmail.com All Things Editorial, Fountain Hills, AZ 85268, USA.
© 2018 Taylor & Francis
REVIEWS IN FISHERIES SCIENCE & AQUACULTURE 87
alligators, which had been hunted nearly to extinction by The results of this partnership have provided significant
this time. benefits to both aquaculture entrepreneurs and natural
As the American alligator was placed under official resource managers, demonstrating one case in which
protection in 1967 (under a law preceding the 1973 commercial use of a public resource has become an inte-
Endangered Species Act) farming alligators for skins gral part of an effective wildlife management plan.
became the most viable option for producing leather
(aside from illegal poaching; Medley, 1970). Mostly con-
Alligator biology
centrated in the southern U.S. states of Louisiana, Flor-
ida, and Georgia, the practice quickly spread to other The reptilian order Crocodilia includes 23 species of
nations. Both the American and Chinese alligator are alligators, caimans, crocodiles, and gharials. There are
farmed intensively today, mostly within each species’ only two species of alligators; American alligator
respective native region. (Alligator mississippiensis) and Chinese alligator (A.
Although farming alligators and crocodiles first grew sinensis). The American alligator, once nearly elimi-
out of the demand for skins (Lyman, 1998), alligator and nated from its native range, has recovered after years
crocodile meat, which was long a part of southern cook- of state and federal protection; the Chinese alligator
ing (especially Cajun cuisine; Marcus, 1993 ) and some remains critically endangered (Thorbjanarson, 1992;
Asian and African cuisines, began to be sold later and Crocodile Specialist Group, 1996). The American alli-
shipped around the world to markets unfamiliar with gator first received federal protection as an endan-
crocodilian meat. Chinese cuisine, based on traditional gered species in 1967. The alligator was removed
Chinese medicine, considers alligator meat to be a cura- from endangered classification in 1987 because of its
tive food for colds and cancer prevention, although there rapid recovery under the protection of state and fed-
is no scientific evidence to support this (Chang and eral laws. It is now classified as “threatened because
Olson, 2008). of the similarity of appearance,” which is a classifica-
A common misconception is that alligators are an tion intended to protect similar-looking crocodilian
easy source of revenue and not difficult to care for in species that are still threatened by international trade
captivity; however, few alligators businesses are success- of their hides and other products (USFWS, 2008). All
ful in the developing world. To offset overhead costs and products derived from crocodilian species are strictly
have a regular source of income, crocodilian facilities can regulated under the International CITES Treaty
add tourism. By utilizing different types of farming, such (https://cites.org/eng/disc/text.php).
as ranching and breeding, combined with tourism, alliga- The American alligator’s native range extends along
tor farming can provide income for people in that area the Atlantic and Gulf coast states from North Carolina
(Brien et al. 2007). to Texas and into northern Mexico, and includes small
Alligator farming has minimal adverse effects on the populations in Arkansas and Oklahoma (Joanen and
environment, though it has at least two positive direct McNease, 1987). The alligator populates mostly freshwa-
effects on alligator conservation. It provides the luxury ter habitats but will occupy slightly saline environments.
goods industry with a reliable stream of product, which Male alligators are known to grow to 5 m in length,
reduces illegal poaching to obtain skins and alligator weigh over a 450 kg, and live a century. Males grow
farmers will release juvenile alligators into the wild to larger than females (3 m maximum) and sexual maturity
support steady population growth. Wild alligator conser- is reached by both sexes at 2 m in length. Along the Gulf
vation has also benefited indirectly from farming. Busi- coast, maturity is reached in 9–10 years but in North
nesses engaging in ranching protect alligator habitats, Carolina, it is not until 18–19 years of age (Fuller et al.,
caring for nesting sites to ensure a healthy population. 1983).
Because there is a fiscal incentive to keep a healthy envi- Alligators are apex predators that have survived since
ronment for breeding alligators, the animals are seen as the Age of Reptiles (The Mesozoic Era), 200 million
an economic resource. years ago. They are distinguished from most other croco-
Today alligator aquaculture is a multi-million dollar dilians based on head morphology and body color. The
industry in parts of the American South, producing snout of the alligator is broader and has no exposed
thousands of farm-raised alligator skins and tons of alli- lower teeth when the mouth is closed compared to other
gator meat annually. The development of alligator aqua- crocodilians. Adult alligators tend to be black while croc-
culture in the United States is a success story of public- odiles are brownish in coloration. Alligators consume
private partnership that has returned an iconic wildlife many types of prey. Young alligators mostly consume
species to its native habitat while creating a profitable insects, snails, crustaceans, and small fish. Larger indi-
use for the private land on which that species depends. viduals consume fish, turtles, birds, and mammals.88 M. NICKUM ET AL.
Alligators, as all reptilians, are tetrapod vertebrates alligator, this paper will focus on that state’s experience
having skin covered with scales or scutes. They repro- with commercial alligator farming since the 1970s.
duce through amniotic eggs and are cold-blooded, or
ectothermic. Alligators cannot regulate their body tem-
Genesis of the management program
peratures physiologically. Like other ectotherms, they
function most efficiently within a narrow temperature The development of alligator farming, from a low-input
range. Their preferred core body temperature is 32–35 C activity relying on the natural production of wild popula-
but they are vigorous at core temperatures of 26–37 C tions to today’s high-intensity farming operations, has
(Brattstrom, 1965). Upper lethal temperature is 38–39 C been many years in the making. Although American alli-
(Colbert et al., 1946) and lower lethal temperature is gator has been used as a natural resource in the south-
2–4 C (Coulson and Hernandez, 1964). In the wild, alli- eastern United States since before European settlement,
gators modify wetlands by creating “gator holes” or small heavy exploitation of the species did not begin until the
ponds. These deeper holes within the wetlands produce early 1800s (Joanen et al., 1997). During most of the
vital habitat for other wetland creatures, especially dur- 19th century, demand for alligator skins fluctuated with
ing droughts. Alligators will also tunnel into banks and the availability of more durable and desirable leather
create dens above water level with access to air. These products in the marketplace. The advent of commercial
deep-water “gator holes” and dens help alligators tanning in the U.S. in the late 1800s, which improved the
find thermal refuges during hot and cold weather durability and aesthetic appeal of animal skins, created a
(USFWS, 2008). growing demand for alligator leather and increased
Alligators can alter their core body temperature, hunting pressure. Strong demand led to widespread
within limits, through physiological and behavioral exploitation of wild alligator populations from the late
adaptations, such as endogenous heat production, which 19th to the mid-20th centuries, resulting in near elimina-
increases with the size of the animal, by contact with tion of the animal from its natural range by the 1960s. In
warmer substrates, basking, and changing activity cycles response, Louisiana banned alligator hunting in 1962
seasonally (Brattstrom, 1965). It appears alligators have (Joanen et al., 1997) and the U.S. government placed the
some vasomotor control of their circulatory system, as American alligator on the federal list of endangered
core, dorsal, and ventral temperatures can differ simulta- species in 1967, where it remained for 20 years (USFWS,
neously (Morgareidge and White, 1969). To maintain 2008).
core temperatures, alligators are mostly nocturnal in By 1987, alligator populations had recovered suffi-
summer and diurnal in winter. These adaptations have ciently throughout the southern U.S. to allow removal of
allowed the alligator to inhabit cooler climates than other Alligator mississippiensis from the endangered species
crocodilians (Lance, 2003). list. However, under the Convention on International
The favorable biological traits of the American alliga- Trade in Endangered Species of Wild Fauna and Flora,
tor and a consistent demand for alligator skin for luxury the U.S. government continues to classify the American
leather products made A. mississippiensis a good candi- alligator as “threatened due to similarity of appearance,”
date for aquaculture production. Scientific research to which allows the federal government to regulate legal
develop alligator farming methods began in the 1970s in trade in alligators and alligator products to inhibit illegal
Louisiana and Florida, and continues to the present day. trade in products from similar-looking reptiles (e.g.,
some crocodiles and caimans) harvested elsewhere in the
world (USFWS, 2008). A primary requirement of the
History of alligator farming
Federal regulations regarding trade in alligator products
Alligator farming is an aquacultural industry worth tens is annual verification by states with exploited alligator
of millions of dollars in the southern United States. It is populations that their harvesting programs are not detri-
practiced primarily in Louisiana, Florida, Georgia and mental to the species’ survival. To comply with this
Texas, where large numbers of wild alligators live in the requirement, the Louisiana Department of Wildlife and
states’ coastal marshes and inland swamps. In 2014, Fisheries (LDWF) employs an extensive research and
farmers in Louisiana, the nation’s largest producer of management program to ensure the well-being and sus-
captive-reared alligators, sold more than 383,000 m of tainable use of the state’s wild alligator populations
skins valued at more than $77 million (LSUAC, 2015). (LDWF, 2016a). This effort, which includes both com-
Florida, the second largest alligator-farming state, pro- mercial alligator farming and wild harvest, has become a
duced only one-tenth of Louisiana’s output that same model of effective crocodilian conservation that is emu-
year (FFWCC, 2015). Given dominance of Louisiana in lated around the world (Joanen et al., 1997; Heykoop
farmed production and wild harvest of American and Frechette, 2001; Moyle, 2013).REVIEWS IN FISHERIES SCIENCE & AQUACULTURE 89
In Louisiana, interest in farming alligators for conser- It is estimated that Louisiana now has a wild alligator
vation and commercial purposes began in 1959 when the population of about two million animals, with an addi-
LDWF initiated an intensive management program tional 300,000 captive-reared alligators present on farms.
aimed at restoring the state’s alligator population to a Despite the harvest of more than 28,000 wild alligators
level that could support sustained annual harvests annually by licensed hunters and collection by alligator
(Joanen and McNease, 1979). Research conducted in the farmers of more than one-half million eggs from the
1960s and 1970s produced information on alligator biol- wild resource each year, the state’s sustainable-use pro-
ogy and husbandry that led to Louisiana’s successful alli- gram has succeeded in maintaining a stable-to-slightly
gator ranching program, which now supports the state’s increasing alligator population since 1972. Additional
commercial alligator industry. Since the initiation of its information on the LDWF alligator management pro-
sustainable-use program in the early 1970s, LDWF esti- gram is available on the agency’s website (http://www.
mates that nearly a million wild alligators have been har- wlf.louisiana.gov/wildlife/alligator-program).
vested, more than eight million eggs have been collected
from the wild for farming operations and the skins of
Alligator farming as a livestock production
five million captive-reared alligators have been sold
enterprise
(LDWF, 2016b).
Although alligator producers are typically identified as Production of farmed alligators at the industrial scale
“farmers,” most are actually ranchers who obtain their that characterizes today’s intensive grow-out operations
stock from wild-sourced eggs rather than from brood- is a relatively recent development. However, alligator
stock housed on their properties, as farmers would do. farming has been of interest to residents of the southeast-
A small number of producers do obtain some eggs from ern United States since the late 19th century, with early
on-site reproduction, but all growers obtain the majority, attempts at captive production recorded as far back as
if not the entirety, of their stock from eggs collected from 1891 in Florida (Lane and King, 1996). Early “farms”
the wild under permits issued by the LDWF. In 2014, were little more than fenced enclosures where alligators
more than 528,000 eggs were collected from 434,000 hec- caught in the wild were held for captive breeding or dis-
tares of Louisiana wetlands to be used in alligator farm- play. The unnatural conditions on these farms often did
ing operations (LDWF, 2016b). Nearly 80% of these not meet environmental requirements of the alligators
wetlands are privately owned. Farmers establish lease for courtship and mating, and few offspring were pro-
agreements with private landowners to collect eggs on duced (Joanen and McNease, 1971, 1980).
their property during the alligator nesting season in For years during the first half of the 20th century, alli-
May–June. These arrangements produce income for the gator farming was perceived by many as an exotic curios-
landowner and provide incentive to maintain agricultur- ity endemic to some southern states. It was not until the
ally unproductive land as income-generating wetland early 1960s, when wild alligator population of Louisiana
habitat for alligator. reached the lowest level in history and alligator hunting
Collected eggs are transported to the farm and incu- was banned, that interest in alligator farming as a sci-
bated at 30–32 C for approximately 65 days. Hatchlings, ence-based, livestock production enterprise developed.
20–30 cm in length when they emerge from the egg, are Alligator farming, it was argued, if practiced as efficiently
stocked in temperature-controlled production houses as other forms of livestock production, could facilitate
and grown to a length of 1–1.5 m prior to slaughter. the restoration of wild populations and support the
A critical component of the LDWF alligator manage- state’s economically important skin trade, which no lon-
ment program is the requirement that producers return ger had access to the wild resource.
12% of farm-raised animals to the wild in the same areas In 1964, the LDWF initiated a research program to
where eggs were collected. This mandate is based on a determine the feasibility of raising alligators in captivity.
determination from population studies that 12% of wild During a nine-year period, a series of studies were con-
hatchlings can be expected to survive to a length of ducted at Rockefeller Wildlife Refuge (Grand Chenier,
1–1.5 m. Returning this percentage of farm-raised ani- Louisiana) to identify management practices for the care
mals to the wild every year ensures that population num- and husbandry of captive-reared American alligator
bers are not reduced by egg harvesting or destructive (Joanen and McNease, 1971, 1975, 1977). Experiments
natural occurrences, such as floods and nest predation, focused on factors such as pen design (optimum size,
and a consistent level of annual recruitment is main- suitable vegetation types, pond configurations, and ratios
tained. LDWF closely monitors the farm-release pro- of dry land to open water areas); male-female stocking
gram to ensure producer compliance and to track effects rates; food sources and feeding methods; reproductive
of the program on the wild resource. biology (including courtship, mating behavior, and nest90 M. NICKUM ET AL.
construction); egg incubation; and alligator growth rates. usually home-made devices designed in a variety of
Results of these studies demonstrated that “closed sys- shapes and sizes—where they are placed in tagged bas-
tem” alligator farming was possible, if not always eco- kets with damp vermiculite, sphagnum, or other bedding
nomical. Farms dependent on captive broodstock were material and held at 30–32 C for approximately 65 days.
unlikely to generate the numbers of offspring needed for The use of hatching containers allows groups of eggs to
commercial viability. Alligator ranching, which relies on be identified by the date and place of collection, so infor-
the collection of wild-sourced eggs, was deemed to be a mation on the characteristics (e.g., date of hatch, percent
more reliable approach (Elsey et al., 1994). Although in hatching success) of clutches obtained from nests in dif-
the early years of the research, when wild alligator popu- ferent areas can be recorded. Hatchlings remain in the
lations were still low, collection of eggs or hatchlings for incubator for 24 hr after hatching to allow the umbilical
commercial purposes was prohibited. cord to separate naturally from the eggshell. They are
Wild populations had recovered sufficiently by 1972 then moved to production houses and stocked at initial
to allow the resumption of alligator hunting in one densities of about two to four animals per square meter.
coastal Louisiana parish in September of that year Stocking densities may vary considerably among farms
(LDWF, 2016b). During the nine years that followed, since the recent removal of minimum-space require-
alligator hunting expanded to other coastal parishes and ments from LDWF alligator farming regulations
was restored statewide in 1981. Populations continued to (LDWF, 2015). Despite differences in production meth-
grow and in 1986, a limited number of egg collections ods, all farmers are careful to maintain conditions that
were permitted for private producers. Use of wild- minimize disease and optimize growth rates.
sourced eggs provided benefits to both producers and Disease is usually not a major problem in most alliga-
wildlife managers. Private growers obtained farm stock tor aquaculture operations, but diseases can appear
at lower cost and many eggs that would have been lost to unexpectedly and develop quickly when they do occur.
natural mortality in the wild were put to productive use. Little information is available concerning diseases that
Also, the requirement that producers return to the wild afflict alligators in the wild; however, among captive-
each year a percentage of their one to two year old reared alligators, dermatitis is a relatively common
farmed stock ensured that exploited populations would disease, particularly among hatchlings, although it can
benefit from consistent recruitment of alligators likely to occur in older alligators, as well (Nevarez et al., 2011).
survive to reproductive age (Elsey et al., 1994). Alligator Bacterial and fungal infections are the causative agents of
ranching (hereafter included in the term “farming”) has dermatitis. The factors that predispose alligators to these
been a successful model of public–private partnership, infections are unknown. Stress may be involved, but
providing both economic and conservation benefits. there is lack of evidence that stressors are the primary
While some crocodilians in other parts of the world cause (Nevarez et al., 2011). Advanced cases of dermati-
are produced primarily or entirely by captive breeding, tis can cause most mortality among captive alligators
most American alligators are produced from eggs taken and, unfortunately, there are no consistently effective
from the wild (Lane and King, 1996; Moyle, 2013; treatments available. Avoiding outbreaks by maintaining
TPWD, 2013). In Louisiana, growers collect eggs in areas good environmental conditions is important. American
approved by LDWF after annual surveys of nest densi- alligator are also susceptible to West Nile virus (WNV)
ties. Surveys are conducted along aerial transects to infection, which can produce high mortality depending
determine number of nests per hectare in different habi- on the severity of an outbreak. Studies indicate that the
tats (e.g., brackish water and freshwater marshes) on American alligator may serve as an “amplifying host” for
both private and public lands. Results of these surveys WNV, with infected individuals serving as a direct
are used in combination with other information to set source of WNV transmission to uninfected alligators
egg-harvest quotas based on alligator abundance in dif- and other susceptible species, including humans (Klenk
ferent parts of the state. The LDWF currently has more et al., 2004; Jacobson et al., 2005).
than 50 such harvest quotas in place (LDWF, 2016b).
Farmers take eggs from nests on properties they lease for
Alligator culture methods
this purpose. Care is taken to mark the top of each egg as
it is removed from the nest to ensure that it remains The first alligator farms were established using captured
upright during transport and incubation; the alligator alligators held in semi-natural enclosures. Eggs and
embryo, which attaches to the top of the egg shell during hatchlings were produced by natural breeding (Wood-
the second day of development, will die if the egg is ward, 1981, Shirley and Elsey, 2015). These enclosures
turned over or handled roughly (Bock et al., 2004). At varied widely in size, water area, and composition of veg-
the farm, eggs are transferred to an incubator—these are etation. Captive breeding facilities require substantialREVIEWS IN FISHERIES SCIENCE & AQUACULTURE 91
capital investment to construct and maintain. Care and and minerals are supplemented into the animal carcasses
preservation of captive alligators is time-consuming and (Joanen and McNease, 1971, 1981, 1987; Masser, 1993b).
costly and consistent successful reproduction is problem- Alligators appear to develop a social structure within a
atic because the social, nutritional, and environmental recognized group. Captured wild alligators can be very
requirements of adult alligators are poorly understood aggressive when penned with unfamiliar individuals.
(Masser, 1993a). It has been observed that adult alliga- Penned wild males have killed rival males and wild
tors that have been raised exclusively in captivity (i.e., females will often not mate with unknown or unaccept-
confinement) accept crowding and confinement consid- able males. Captive reared alligators are much less
erably better than wild captured animals. Captive adults aggressive toward each other especially if penned
that were raised together appear to develop a social together before three years of age. Courtship and breed-
structure and breed more consistently than wild brood- ing occurs between April and July depending on the cli-
stock (Masser, 1993a). mate. Courtship behavior includes vigorous activities
Adult breeding enclosures have not had a consis- like rapid swimming and bellowing. Courtship usually
tent size but smaller pens (4000 to 8000 m2) function occurs just after sunrise in deep water. Repeated copula-
best if the animals need to be captured from the tion is common (Joanen and McNease, 1971; Masser,
pens. States that allow holding alligators in captivity 1993a). Reproductive success of captive alligators has
have specific regulations for pen design based on been problematic.
telemetry studies of wild adults (Joanen and McNease, Nest building and egg laying takes place at night. The
1970, 1972). Maintaining adult alligators in pens female constructs the nest from the surrounding vegeta-
requires exceptionally strong fencing with require- tion and soil. Nests are round, mounded structures and
ments on welded wire mesh, height, post spacing, eggs are deposited in the center of the mound with vege-
rounded corners, wooded frames along the fence bot- tation between layers of eggs and a 0.3 m covering of veg-
tom and double hinged and latched gates. Man-made etation. The female guards and protects the nest from
water structures include deep water courtship ponds predators and other nesting females. Clutch size varies
(i.e., minimum 1.5 m) and small isolation ponds. with condition and age of the female. Larger females usu-
Water to land ratio within the pens should be 1:3 ally lay more eggs. Clutch size averages 35 to 40 eggs
and pond design should maximize shoreline area with fertility in the range of 70 to 95%. Embryo survival
(e.g., “M,” “S,” “W,” or “Z” shapes). Males appear to varies from 70 to 95% and hatching rate from 50 to 90%
fight less when they cannot see each other. Vegetation (Masser, 1993a). Eggs taken from wild alligator nests and
was generally native marsh species with a rank grow- hatched have higher egg fertility, embryo survival, and
ing grass 0.6 to 0.8 m tall preferred (Joanen and hatching rates than the eggs of captive alligators.
McNease, 1987; Masser, 1993a). Some producers add While some farms that maintain captive broodstock
hay bales in the nesting season to supplement natural as outlined above exist, few farms practice captive breed-
vegetation and add shade awnings to prevent over- ing because of the land requirements, care and mainte-
heating and reduce burrowing (Masser, 1993a). nance of the adults, and the capital and time investments
Adult stocking density should be maintained at four (Shirley and Elsey, 2015). Today most alligator farms are
to eight animals per hectare but higher or lower densities based on the “alligator ranching” concept.
are preferred by some producers. Female to male ratios Alligator ranching revolves around collection of eggs
in the pens is usually at 3:1. Adult alligators 6 to 20 years from alligator nests in the wild or in some cases captur-
old are usually dependable breeders with females 8 to ing hatchings then rearing them in intensive grow-out
10 years old the most consistent breeders (Joanen and systems. Louisiana, Florida, and Texas allow eggs and/or
McNease, 1987; Masser, 1993a). hatchlings to be removed from the wild under specific
Pens should have several feeding stations maintained permits regulated by the state Wildlife, Game and Fish,
near basking areas or near the edge of ponds that are eas- or Natural Resource agency (Shirley and Elsey, 2015). In
ily accessible from regularly maintained roads or trails to these states, censuses at the end of the breeding and nest-
assure the safety of staff. Breeding adults are feed at ing season are conducted to estimate the number of alli-
4–7% body weight per week when water temperatures gator nests and based on the number of nests permits are
are above 20 C. Once per week is sufficient with particu- issued to the landowner for collection of a specific num-
lar care not to disturb adults during breeding, nesting, ber of eggs (Masser, 2005; Shirley and Elsey, 2015). In
and hatching periods (i.e., February through August). Florida and Texas, eggs can be collected from only 50%
Diets of adults usually consist of legally captured fish, of the estimated nests. In Louisiana, permits issued to
birds, or mammals as available with some commercial landowners have specific numbers of eggs collected from
alligator diet. If no commercial diet is fed then vitamins each property and a percentage of the hatchlings must be92 M. NICKUM ET AL.
released back into the wild at age two (i.e., > 0.9 m in grow-out. Uniform sizing reduces competition among
length). These management practices assure sustainable the hatchlings (Joanen and McNease, 1976). Density of
wild population (Taylor and Neal, 1984; Shirley and hatchlings was maintained at 10 per m2 in the grow-out
Elsey, 2015). chambers in the first year then reduced to 3.3 per m2
Eggs are collected generally from airboats or helicop- until age 3 (Joanen and McNease, 1977).
ters with special care to keep the aggressive females at
bay while the nest is opened and eggs collected for trans-
port to grow-out facilities (Masser, 2005; Shirley and
Production and markets
Elsey, 2015). Collection of eggs is time sensitive because
alligator embryos are easily killed by jarring particularly Growth of hatchling alligators to a marketable length
from 7 to 28 days. After 28 days of incubation, the of approximately 1.5 m takes about 14 months on
embryos are resistant to most handling damage. Eggs most farms, depending on air and water temperature
must be kept in the position as laid and can only be repo- and food availability. Some producers have deep wells
sitioned in the first 24 hr after being laid. Eggs are that provide a year-round supply of geothermally
marked on top so the position can be maintained during heated water; others heat water prior to use. In most
transport and incubation. Eggs are placed marks up on cases, growers will maintain temperatures of 29–32 C,
20 to 30 cm of moistened nesting material and another 5 with the highest temperature provided to hatchlings.
to 12 cm of nest material on top for transport (Joanen Temperatures are gradually decreased as the animals
and McNease, 1987). The age of eggs and where they are grow. Producers who can maintain optimum
in development can be determined during incubation by temperature throughout the production period will
candling them and observing opaque banding patterns produce a marketable alligator in the shortest time
(Ferguson, 1981). (Figure 1 and 2). Some producers use insulated tanks
The incubation period for the American alligator eggs for grow-out, although most utilize insulated build-
is 65 days. Hatching rates in the wild are less than 60% ings comprising one or more pens with standing
(Joanen, 1969). Hatching rates of eggs removed from the pools of water on a concrete floor, often adjacent to
wild and artificially incubated usually exceeds 90% dry areas for basking. Alligator “houses” come in a
(Masser, 2005). During incubation, the eggs are placed in variety of designs from Quonset types to long rectan-
mesh trays in a single layer surrounded by nesting mate- gular sheds similar in shape to commercial poultry
rial. Decomposition of the nesting material is critical to houses. The LDWF, and equivalent agencies in other
aid in breakdown of the eggshell so hatchlings can pierce states, have specific requirements for alligator produc-
the eggshell. The depth of the nesting material should be tion facilities (LDWF, 2011; TPWD, 2013; FFWCC,
about 15 cm. The incubation baskets are positioned 7 to 2016). These may be updated periodically as the
8 cm above a heated water bath. The relative humidity agency’s experience with the industry warrants
should be a minimum of 90% in the incubator. Nesting (LDWF, 2015). Masser (1993b) and Lane and Ruppert
material is moistened with warm water as needed to (1998) provide brief descriptions of typical alligator
maintain dampness (Joanen and McNease, 1976). Incu-
bation temperature should be between 29.4 C and
32.7 C. After hatching, the hatchlings are maintained in
the incubation chamber for 24 hr to allow complete sepa-
ration from the egg and umbilical cord detachment
(Joanen and McNease, 1979). Sex expression can be
manipulated by temperature. Eggs incubated at 29.4 C
to 32.7 C will be mixed sex animals. However eggs incu-
bated above 33 C will become all males and those below
30 C will be females (Ferguson and Joanen, 1982).
Baby alligators make peeping or chirping sounds dur-
ing and after hatching. In the wild, this stimulates the
female to open the nest so hatchings can escape. In
the incubators, unhatched eggs can be opened to free the
hatchling, if done without damaging or detaching the
umbilical cord. Twenty-four hours after hatching, hatch-
lings are sorted into uniform size groups and relocated Figure 1. Alligator Research Facility, Louisiana State University
into environmentally controlled chambers for further Agricultural Center (photo by R. Reigh).REVIEWS IN FISHERIES SCIENCE & AQUACULTURE 93
During the first few months of grow-out, juvenile alliga-
tors are fed a high (e.g., 56%) protein diet composed pri-
marily of animal tissues, such as slaughterhouse by-
products and fishmeal. Farmers typically switch to a
lower (e.g., 45—48%) protein diet about 90 days after
hatching. Because the minimum dietary requirements of
virtually all essential nutrients are unknown for the
American alligator, the compounded diets currently used
in the alligator-farming industry are based on known
nutritional requirements of other farmed animals and
the best guesses of commercial feed manufacturers
regarding appropriate diet composition for a reptilian
carnivore. Current diets are likely to be over fortified
with all essential nutrients to ensure that no deficiencies
exist. This provides a margin of safety for both the feed
Figure 2. Juvenile alligators in temperature-controlled tank, Alli- manufacturer and the farmer, but also adds cost for
gator Research Facility, Louisiana State University Agricultural
nutrients that are not utilized and which contribute to
Center (photo by R. Reigh). (Alternate photo provides a wider
view of the tank; same caption as Figure 2; photo by R. Reigh). water quality problems in production systems (Reigh
et al., 2013).
production houses, although a wide variety of designs As in all intensive aquaculture operations, feed cost is
are in use. a major component of alligator production cost. Farmers
Regardless of the design of a farm, in all cases the are interested in identifying the nutritional requirements
availability of abundant quantities of warm water is a of American alligator to support the development of less
necessity. Alligator pens are drained, washed, and refilled expensive diets that will provide options for greater cost
with clean water every few days to maintain adequate control. Some of the early work with alligator nutrition
hygiene in the production house. Wastewater is directed involved academic studies of metabolism (Coulson and
to storage ponds where it may be held for eventual appli- Hernandez, 1983), as well as practical studies of dietary
cation to agricultural land or allowed to evaporate. protein-energy balance and suitable sources of energy for
Sheffield et al. (2008) identified many considerations feeds (Staton et al., 1990a, 1990b). More recent studies
involved in the storage and use of waste water from alli- have evaluated protein-energy ratios in compounded
gator production facilities. The cost of heating water and diets (Reigh et al., 2013), determined the availability for
the availability of water in sufficient quantity, and of ade- alligator of energy and amino acids in feedstuffs (Reigh
quate quality, to meet production needs are among the and Williams, 2013), tested the first plant-based diets for
primary concerns of persons designing or managing an alligator aquaculture (Reigh and Williams, 2014), and
alligator farm. identified optimum feeding rates (Reigh and Williams,
Besides the critical need for a warm, clean environ- 2016). However, much work remains to be done to
ment, good quality food is essential for the profitable identify the nutritional needs of this poorly understood
production of farmed alligator. In the early days of alliga- species.
tor farming, producers fed whatever meat products they The Louisiana alligator industry utilizes best manage-
could obtain—including red meat, poultry, and fish— ment practices in all aspects of alligator farming
sometimes mixed with pelleted animal feeds and vitamin (LDWF, 2011), including the use of humane slaughter
supplements (Joanen and McNease, 1971; Elsey et al., methods, which are regularly reviewed by veterinarians
1994). While such diets could be reasonably effective, and the LDWF and modified as necessary to ensure that
they were difficult to store, unpleasant to handle, and the best available practices are adopted by producers
prone to creating water quality problems. The need for (LDWF, 2015). Most farmed alligators are harvested at a
dry, off-the-shelf alligator feeds was eventually addressed length of 1–1.5 m after 14–16 months of growth; how-
with the advent of commercially manufactured, extruded ever, production times can vary considerably among
diets produced in the same manner as dry pet foods and farms depending on culture conditions. The skins of ani-
pelletized fish feeds. Formulated diets are now the indus- mals in this size range are used for watchbands, belts,
try standard for alligator production. wallets, and other small leather items. Skins from larger
When hatched, a young alligator may subsist on the animals may be suitable for handbags, footwear, and
internal remnants of its yolk sac for several days, after similar products. The most valuable part of an alligator
which it will accept a feed pellet of appropriate size. is the belly skin, which has an attractive scale pattern94 M. NICKUM ET AL.
and particular characteristics that are well suited to the American alligator is commonly found; however, all the
tanning process. During slaughter, the belly skin is meat currently produced from farmed animals is sold.
removed from the carcass, scraped of excess tissue, Meat production, as a by-product of the skin trade, fluc-
salted, and rolled for storage. Skins are sold to tannery tuates with global demand for alligator skins. In 2015,
representatives who visit farms to inspect, grade, and Louisiana farmers sold more than 445,000 kg of alligator
purchase skins on-site. The majority of Louisiana- meat worth nearly $US7 million (LDWF, 2016b). As was
produced skins are shipped to France or Italy for tan- the case with skin sales, meat sales in 2015 and 2014
ning. Domestically, one alligator tannery operates in the (465,000 kg that year) were the highest on record for the
state of Louisiana, and three other U.S. tanneries, in Flor- state’s farmed alligator industry.
ida, Georgia and New York also process alligator skins. An interesting value-added aspect of alligator aqua-
culture is the production of novel compounds with
potential biomedical applications. Alligator blood is
Markets: Present and future
known to possess antimicrobial properties that could
Alligator skins are sold by quality grade and belly width. yield compounds useful as bacterial growth inhibitors
Grade 1 skins have no discernible blemishes (e.g., for wound dressings and other medical applications
scratches or scars) and command the highest price. Belly (Merchant et al., 2003). Research at Louisiana State
width is measured at a standard point behind the front University has identified a number of useful compounds
legs, running from the ventral midline to approximately in alligator tissues (e.g., collagens, elastin, proteoglycans)
half-way up each side of the body. In 2015, more than that could have a variety of medical, cosmetic, and food
327,000 skins were sold in Louisiana for more than applications (Bogren, 2007).
$US64.2 million (LDWF, 2016b). Average belly width of In 2013, the last year for which global market data
skins sold that year was 26.2 cm, with an average selling have been published, the worldwide crocodilian skin
price of $7.50 per centimeter. Skin sales in 2015 and trade totaled 1,888,634 skins, of which 878,332 skins
2014 (342,000 skins that year) were the highest recorded (46.5%) were “classic skins” derived from American alli-
since Louisiana’s farmed-alligator harvests began. gator and seven species of crocodiles (Caldwell, 2015).
In addition to skin sales, markets for alligator meat Caiman skins (four species) composed the remainder of
have grown in the U.S. and internationally, primarily in the trade. Within the classic-skin category, American
Asia. During eight years of the ten-year (2004–2013) alligator constituted 54.8% of the global market, followed
period described by Caldwell (2015), the global market by Nile crocodile at 29.4%. The 2013 market for nearly
for crocodilian meat from all sources averaged about 500 1.9 million skins was the largest observed during the ten-
metric tons (mt) annually, with substantial increases — year period reported by Caldwell (2015). During this
to nearly 1000 mt annually — in only two of the years on time (2004–2013), total global trade averaged 1,404,433
record (2006 and 2007). Alligator meat from the U.S. § 256,121 crocodilian skins per year; of this total, the
was the primary trade item until 1992; exported to trade in American alligator averaged 342,517 § 74,167
Canada, Japan, Taiwan, China, and the United Kingdom. skins annually.
U.S. exports began falling in the mid-1990s. In Alligator farming serves a particular segment of the
2011–2013, Canada and Hong Kong were primary skin trade. As such, farmed skins do not compete in
export markets for U.S. alligator meat (Caldwell, 2015). the marketplace with skins obtained from wild alliga-
Alligator meat is lean, averaging 20% protein and tors taken by licensed hunters. Original concerns
3–5% fat depending on cut (i.e., tail vs. body meat). Rela- about potentially negative impacts of alligator farming
tive to beef and pork, it is a low-fat food containing pri- on management of the wild resource (e.g., by making
marily unsaturated fats—69% in alligator vs. 47% and poaching more difficult to control) have proved to be
56% unsaturated fats in beef and pork, respectively (Leak unfounded. Alligator farming has, in fact, significantly
et al., 2003). While consumption of unsaturated fats is contributed to conservation of the wild resource while
recommended for human health, the chemical structure providing economic benefits to farmers and land-
of these compounds makes them highly susceptible to owners (Moyle, 2013).
oxidative rancidity when exposed to air. Thus, it is criti- It is difficult to estimate the growth potential of alliga-
cal for alligator meat to be handled and stored properly tor farming, but the market for American alligator skins
to retain quality. appears to have been relatively stable for more than a
In most parts of the United States, alligator meat is an decade. In 2015, the number of skins sold by Louisiana
unusual commodity. Given its novelty as a food item, a farmers, who produce the majority of alligator skins that
market development campaign will be needed to sub- enter global trade, was not greatly different (327,228;
stantially increase demand outside the areas where LDWF, 2016b) than the average number produced inREVIEWS IN FISHERIES SCIENCE & AQUACULTURE 95
2004–2013 (342,517; derived from Caldwell, 2015). The sometimes were added. Today, formulated feeds
current business model, based on exploitation of a man- designed specifically for alligators are the norm. Dis-
aged, natural resource, is susceptible to impacts from ease is seldom a problem in alligator production
natural disasters, such as hurricanes and floods, which operations. As with other forms of aquaculture, clean
can destroy resources that support the farming industry. water, sanitary conditions, and high quality feed lead
Producers are particularly exposed to the effects of eco- to few disease problems.
nomic recession resulting from the high cost of luxury Skins, especially the underside, are the primary prod-
products made with alligator skins; and the use of alliga- uct from alligator aquaculture; however, the meat has a
tor skins for what some consider to be unnecessary prod- steady market as a novelty item in niche markets. Alliga-
ucts is controversial among consumers (Summers et al., tor flesh is lean, firm, and mild-flavored, averaging only
2006). Given the nature of the natural, economic, and 3–5% fat. It is considerably richer in unsaturated fats
societal constraints on industry growth, it would be pru- than beef or pork. Although leather products made from
dent to expect that alligator farming will grow at a pace alligator skins have strong, steady consumer appeal, the
similar to that experienced during the last decade. The fact that these products are found primarily in luxury
development of new markets for alligator products, with markets is something of a mixed blessing. The demand is
a wider range of price points, could stimulate additional relatively steady and predictable, but the size of the mar-
growth within the limits that the natural resource can ket is limited in comparison to less exotic forms of
support under current regulations. Growth beyond that leather. The effects of weather events on reproduction of
limitation will require the development of a new para- wild alligators, the source of most eggs, are an uncontrol-
digm for alligator production; one based on development lable factor for alligator farmers, as are economic condi-
of a strain of genetically selected animals more similar to tions that can affect demand for products. The future,
domesticated livestock than to the wild creatures upon nevertheless, for alligator aquaculture appears to be one
which the industry now depends. of “steady as we go;” a future much like the experiences
of the past 10–15 years; not marked by sudden drops in
the market, nor rapid expansion.
Summary and recommendations
American alligator “farming” in the form of maintaining
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