In recognition of the enormous value of LAL to world health, we must question if there is a need to limit the number of HSCs required to produce LAL.

Last year, we celebrated the 50th anniversary of Jack Levin’s discovery of Limulus amebocyte lysate (LAL) reagent. By 1971, the pharmaceutical industry recognized the necessity of LAL for prevention of harmful endotoxin contamination of injectable products. An LAL industry rapidly emerged to meet the need for healthcare requirements. The new industry conserved the horseshoe crab (HSC) from the outset by establishing a return-to-sea policy following bleeding of specimen and by educating the public and watermen about the new-found value of HSC. The LAL reagent for endotoxin (pyrogen) testing was soon required for all aspects of drug manufacturing and led to the elimination of dangerous pyrogenic reactions in the world’s supply of injectable medicines. In recognition of the enormous value of LAL to world health, we must question if there is a need to limit the number of HSC required to produce LAL. 

There are advocacy groups that have erroneously described the threshold level as an upper limit for LAL harvesting and suggest that the Fisheries Management Plan restricts the number of HSC bled by this industry. These groups also falsely suggest that the biomedical industry adversely impacts on HSC sustainability, even though there is no evidence to support such contentions. It is clear that the bait fishery is the industry that leads to poor HSC sustainability. The HSC thrives in those regions where bait fishing is banned, such as South Carolina and New Jersey. Conversely, the baiting practices that are popular in New England water is likely the reason why HSC populations are declining there. A better use of time by these advocacy groups would be directing their efforts towards suitable artificial bait for eel and conch fisheries.  The supply of HSC seemed endless until the eel and conch fishery discovered them as ideal bait. The number of spawning HSC in Delaware Bay, the largest concentration of HSC in the world, was sharply reduced. The ASMFC (Atlantic States Marine Fisheries Commission) recognized the need to restrain the bait fishery to sustain HSC stock. The ASMFC thought it equitable to manage both bait and LAL fisheries. 

If LAL is so valuable, why was there a perceived need to manage their use of HSC resources? The 1998 Fisheries Management Plan (FMP) for the horseshoe crab designed a plan to sharply reduce the bait industry throughout the Atlantic coast. The FMP also created a threshold to trigger management action for harvesting HSC for production of LAL. The FMP was to reevaluate potential restrictions on HSC biomedical catch should the estimated mortality exceed 57.5K specimen. This number was selected arbitrarily and was not envisioned as an unacceptable quantity or upper limit for biomedical harvest.  The number was approximately 15% of an estimated mortality for a 250K biomedical harvest of HSC in 1998 plus 50% for growth in reagent need.

Biomedical catch has grown to at least 600K, which means that the 57.5K estimated mortality exceeded the arbitrary threshold assuming a 15% of specimen in biomedical hands. The FMP Board asked the biomedical firms to provide assurance that all possible measures were taken to minimize mortality.  In response to the HSC Board’s concerns, a Working Group of biomedical and State fisheries representatives that included myself met in 2011 to create Best Management Practices (BMP) to minimize mortality associated with the collection and handling of specimen. The BMP specified behaviors such as timely transport, protection from sun exposure, prompt return to sea, and training of watermen in best handling techniques. The BMP is flexible to accommodate differences in climate, habitat and size of HSC with respect to a LAL firm’s geographical location. The Working Group advanced the concept of ALARA where the goal was to keep mortality to ‘As Low as Reasonably Achievable.’  ALARA is used by the nuclear industry to minimize occupational radiation exposure. The LAL biomedical group recommended to the FMP in 2014 that the ALARA concept replace the threshold concept because there is no evidence of overfishing or poor management behavior on the part of US biomedical firms. No further action was taken by the HSC Board which indicated their satisfaction with the response of the biomedical industry.

LAL related mortality is not well understood. Clearly, bleeding never results in immediate death. However, the stress of collection and transport processes produces the observed mortality that is limited to HSC that are unhealthy or near end of life. The most reliable studies indicate that 90% of HSCs survive the careful handling by biomedical firms. The bleeding of HSC is very analogous to collection of human blood by the Red Cross. It is a little painful and inconvenient, but is not destructive. Both collections are made responsible on individuals that are screened for well-being and treated respectfully.

In conclusion, the LAL industry has established an exemplary record of minimal loss of HSC. The implementation of Best Management Practices negates the need for limiting biomedical harvesting of HSC.  Loss of a small proportion of HSC in the hands of biomedical firms is inconsequential and justified by the immense value of LAL.

How to Cite:

Cooper, James. The ALARA Concept and Horseshoe Crab Harvesting. Eureka blog. Aug. 3, 2016. Available: