Increasing Sustainability of Crawfish and Low Salinity Shrimp Production in West Alabama

Short vs. Long Neck Traps

The mean time taken to harvest tall and short neck traps was similar for both ponds.  Even though the tall traps were more difficult to handle, the majority of the time to harvest the traps was to walk the pond perimeter.  Mean production of tall traps placed on pond bottoms was very similar to those placed on pond slopes in N15.  In S8, the production appeared greater in the tall traps than in the short traps, however 95% confidence intervals placed around both means overlapped, so the means were not significantly different.  

Harvesting tall traps in deep water was more daunting and energy sapping than harvesting short traps.  This is because deeper water inhibits movement, and because the tall traps most be lifted much higher in the air in order to dump out the crawfish. The repetition of this action is quite tiring.  In 2021, pond depths will be lowered in order to make harvesting simpler.  Additionally, the placement of tall traps will be modified to allow them to be more easily removed for dumping and then replaced.  In the shallower pond, all traps will be placed on the pond bottom and none on the slopes.  It is thought that this may increase the catchability of traps.

Table 2. Summary of testing tall vs. short neck traps during 2020.

German Creek Crawfish 

Production and limited enterprise budgets for 2 ponds at GCC follow.  Yields ranged from 334 to 813 lbs/A, and returns above costs ranged from $487 to $1,805/A.  Even the lower yielding ponds were profitable.  These ponds have been in production since 2016 and their yields have stabilized over time.  Initially, there was some financial loss when the new ponds did not produce as expected.  

GCC ponds were initially constructed for catfish, so mid depth and depth at the drain end would be 3 to 4 ft.  This depth is too great for crawfish and traps, so traps are placed only along the inside periphery and in the shallow end of the ponds.  Crawfish ponds are usually shallow and the whole pond bottom can be laid out with traps.  

During both years the yield from BD North pond was much greater than that from BD South.  Also, the crawfish in PD North are larger than those in PD South.  These ponds lie next to each other, so the difference is thought to be due to filling time.  Both ponds are planted with millet in late July, but BD North is flooded in October and BD South is not flooded until January.  It is thought that the earlier flooding gives crawfish greater access to food and a longer growing season.  These ponds are rented from someone who hunts ducks and therefore has alternative goals for the use of ponds.

Enterprise Budgets for GCC

Greene Prairie Aquafarm

The total quantity of crawfish harvested in  ponds at GPA during 2020 and 2021 appear in the following tables.  Pond N14 produced an acceptable quantity of crawfish, but ponds N15 and S8 produced relatively few crawfish in 2020.  In fact, many more crawfish were harvested in N15 and S8, but they were unmarketably small and thrown back to the pond.  These ponds were regularly fed with cattle cubes, but crawfish did not gain much weight.  We think that grass carp, put in these ponds earlier to control weeds, ate the cattle cubes and other vegetative material that crawfish might have consumed.  So N15 and S8, were drained and the carp removed.  The inside periphery of the ponds were seeded with Japanese millet, and then refilled in the fall once the millet had grown. 

In 2021 production was remarkably higher in N15 and S8, but lower in N14.  There was an episode of low dissolved oxygen in N14 and dead, marketable size crawfish were observed floating around the edges of the pond.  Also, green sunfish were occasionally observed in N14 traps.  The sunfish likely consumed young crawfish.  Production was subsequently lower in this pond. 

Removal of grass carp from ponds N15 and S8 allowed these ponds to produce much higher quantities of crawfish.  Crawfish ponds need to be kept free of fish that may compete for food or consume the crawfish directly.  While this observation comports with proper aquaculture management, it is difficult to keep ponds free of sunfish that inhabit the streams to which crawfish ponds are discharged.  For example, Pond N14 had been drained at the end of 2020 and it was during this time that the green sunfish were able to infiltrate the pond.  These fish are able to ascend moving water from draining ponds.

In 2021 we added another pond to crawfish production.  This was Pond N10 which was a shrimp production pond.  The crawfish had stocked themselves in this pond by crawling out of Pond N14 during 2019 and 2020 seasons. We set out traps in half of this pond in 2021 and were able to catch a significant quantity of crawfish.   The number of traps was increased for the 2022 season to go around the whole periphery of N10 with the expectation that this pond would produce much crawfish after another year of natural population expansion.  No special food is given to these crawfish, so their harvest is largely free of costs.  A disadvantage of locating traps in the shrimp pond is that shrimp also become caught in the traps after they reach 8 to 10 g in size.  They have to be separated from the crawfish and released back to the pond or they will die.  As a result, the traps are discontinued in late June even though crawfish are still being caught.

Economics of Production in GPA Ponds

Limited enterprise budgets were made for each of our crawfish production ponds for each year.  These budgets are limited because they are based primarily on operating costs, and with the presumption that ponds had already been constructed for other purposes.  Pond construction and land costs would represent a much larger fixed investment to anybody just getting into the business.

Comparison of Farm Production Characteristics

The production yields were significantly higher for GCC than GPA.  It is probable that harvest pressure was slightly greater at GCC and this would have accounted for some of the higher yields.  However, crawfish grew better at GCC most probably because they had more food available to them in the form of planted forage crops.  The traditional system that relies on annual plantings of crops like millet and sorghum seem to do better.  In Louisiana, the crawfish rely on forage from rice that often is double cropped with crawfish.   

In 2020, GPA relied totally on added feed products like cattle cubes, catfish feed fines and shrimp feed.  In the Fall of 2020, the ponds were seeded around the peripheries with Japanese millet so that a partial cover crop grew before flooding.  In February of 2021, several large round hay bails were rolled into the ponds and unravelled at a rate of about 1 roll per 1.5 acres to provide additional forage for crawfish.  Cattle pellets, catfish feed fines and some shrimp feed was added to ponds as in 2020.  In essence, a hybrid approach was taken in 2021 between the traditional forage system and the deep water feed approach taken the year before.

Net economic returns were much greater for GCC than GPA.  This was due in small part to a higher selling price of $3.00/lb compared to $2.75/lb at GPA. However, the great difference between economic returns at the two farms was directly related to greater yields at GCC, because the costs were similar for both farms.  The efficiency of production per input cost was much greater at GCC.  Costs at GCC included a significant charge for rent that GPA did not have.  The cost of feeds and feed products for GAA were higher per acre than seed for forage crops at GCC.

In the future, GPA will trend towards the traditional system and seed ponds with a cover crop for flooding later in the Fall where possible.  One of our ponds is difficult to drain, so this pond will be supplied with hay bails and low amounts of feed products.

Average yields of crawfish in rice fields has been reported as 600 lbs/A and cost of production as $750/A.  The yields and and costs associated with the Alabama traditional system are similar.  This is surprising given that crawfish farming is not practiced to a great extent in Alabama because it is not thought to be very profitable.  Net returns per pound at both farms was between $1.44 and $2.05.  This is high for an animal product.  However, the season is limited and the labor requirements for working the ponds is high and arduous during the harvest period.  These factors probably tend to limit entrance to farming crawfish.  Also, the ponds in this case study were built for other purposes and the costs were not included in the enterprise budget.  However, there are quite a number of extinct catfish ponds in the surrounding counties that could be put into crawfish production without a high investment.

Crawfish as a Diversification for Shrimp Farming

GPA is primarily a shrimp farm and an objective of this study was to evaluate if crawfish farming might be useful for diversifying production or for adding an additional product to ponds already producing shrimp.  Net income with crawfish at GPA ranged from $422 to $769/A.  Yields will be higher in the future as the system stabilizes.  Comparable shrimp income might be 2 to 3 times that amount.  However, the costs and risks of producing crawfish are far less than for shrimp.   Crawfish is a good product for ponds that are difficult to drain or not easily managed.   They are not as productive as shrimp, but the demand is high, the costs of production are relatively low, and risks are minimal.

The addition of crawfish to shrimp ponds as an co-product to increase net income seemed simple, but is not problem free.  First, shrimp ponds cannot be seeded with a cover crop, nor can hay be added for forage.  Shrimp ponds are filled during the Winter and drained in September to October every year.  Crawfish can repopulate these ponds naturally, but many young are lost during draining.  Crawfish trapping begins in late March and could continue through the first of July.  Shrimp are stocked in early May and become big enough to get caught in crawfish traps by mid June.  Therefore, traps must be removed from ponds before crawfish harvest is completed.  Also, the labor requirements of crawfish harvest overlap to an extent with those required to acquire, acclimate and stock shrimp.  However, the crawfish catch from shrimp ponds can be sizable and the costs are minimal, so they can be a good co-product with shrimp.  There are early indications that an additional net income of $500 to $600/A might be harvested from shrimp ponds as crawfish.