An estimate of intrinsic rate of increase for stone crabs was not available. Most female Stone crabs in Florida spawn when they reach approximately 2 years (Florida Fish and Wildlife Conservation Commission, 2003). Male stone crabs can live to at least 8 years old (Restrepo, 2004). The maximum estimated age for females is approximately 7 or 8 years old. However, there is no good method to estimate age of Stone crabs. Molt frequency and average molt increment are usually used for age estimates (Bert, Pers. Comm., 2004).

Stone crabs are found from North Carolina south around peninsular Florida to the Yucatan and Belize and throughout the Bahamas and Greater Antilles (Florida Fish and Wildlife Conservation Commission, 2003). In the northern and western Gulf of Mexico (northwest Florida to Tamaulipas, Mexico), gulf Stone crabs replace Florida stone crabs. In addition, there are zones of secondary contact and hybridization between species in the gulf between Cedar Key and Cape San Blas and in the Atlantic between Cape Canaveral and Charleston, South Carolina (Florida Fish and Wildlife Conservation Commission, 2003). The range of each species is relatively small.

Claws are removed from captured Stone crabs above the size limit, and the live crab is then returned to the water with the possibility of survival (Florida Fish and Wildlife Conservation Commission, 2003). If the claws are removed correctly, a thin membrane forms over the wound and prevents bleeding. If a crab is de-clawed incorrectly (i.e., if part of the body is taken with the claw), the crab may bleed excessively or be unable to regenerate a new claw, and the likelihood that the crab will die significantly increases (Florida Marine Research Institute, 2004). Regenerated claws can be identified by a dotted or dashed pattern on the inner propodus. In contrast, the pattern on the inner propodus of an original claw resembles a fingerprint (series of parallel lines that are slightly raised off the propodus). Estimates of the percentage of regenerated claws that re-enter the fishery are approximately 8% (Bert, Pers. Comm., 2004).

Although the majority of crabs that are de-clawed do die, we added points to account for the potential for crabs to be more resilient to fishing pressure if claws are removed correctly.

Stone crabs have relatively high fecundity. A single female may produce four to six egg masses or "sponges" during a single mating season with an average of 4.5 spawnings per molt (U.S. Fish and Wildlife Service, 1984). Each egg sponge may contain between 160,000 and 1,000,000 eggs; The number of eggs spawned is positively correlated with size of the female (U.S. Fish and Wildlife Service, 1984). After spawning, females attach eggs to the abdominal setae on their pleiopods. Spawnings may occur up to six successive times without an intervening mating (U.S. Fish and Wildlife Service, 1984).

Adequate information to determine population abundance and health is not available. A Stone crab monitoring program is in the process of being put in place as of Fall 2004, but has not conducted any fishery independent assessments. (Bert, Pers. Comm 2004). In the past managers have considered the Stone crab populations to be stable because the spawning potential ratio (proxy for abundance) is greater than 70% (U.S. National Marine Fisheries Service, 2001). However, we awarded a score of 2 due to the lack of an authoritative, scientifically-based assessment.

Catch per unit effort and overall catch have been declining by small amounts over the last 10-15 years. At the same time, effort has increased substantially. It has not been clear to managers whether the slight decline in catches represents a decline in population abundance, or a wider distribution of the catch among fishers (Bert, Pers. Comm. 2004). No points were subtracted here due to the lack of conclusive data regarding the overall trend in population abundance.

Unpublished data from trapping studies in the Tampa Bay area over the last 15 years suggest that the age and sex distribution of Stone crab populations is skewed. Regarding the age distribution, there are several indicators that the majority of catch is likely comprised of new recruits into the fishery. Fluctuations around the mean catch levels have been increasing for the last decade. Since recruitment varies each year, the increase in fluctuations could suggest that the majority of the catch is new recruits and that the population is comprised of younger crabs. Also, fishermen complain that jumbo claws, or claws from larger, older crabs, are almost non-existent now.

Sampling data from fished and unfished areas suggest that the population may be skewed toward females. Traps are biased toward catching the largest crabs with the largest claws because smaller crabs that enter traps are usually either killed and eaten by larger crabs, or escape from the traps. In unfished areas, the catch in traps is heavily skewed towards males. However, in heavily fished areas, the catch was mostly females. The fact that sampling heavily fished areas results in catching mostly females suggest the possibility that large males may be fished out. Although there is no true indication that there's an overall population decline, these indicators suggest that the age and sex distribution is unhealthy. The populations is considered at least fished to the maximum sustainable yield (Bert, Pers. Comm., 2004).

Stone crabs are high-level carnivores and undoubtedly influence the abundance of large mollusks, which are their preferred prey item. The long-term, heavy fishing pressure exerted on Stone crabs in the Gulf of Mexico nearshore waters off Florida has likely influenced the food web. However, the ways in which it has affected the food web are unknown (Bert, Pers. Comm., 2004). Thus, no points were deducted here.

Traps are used in the Florida stone crab commercial and recreational fisheries. Recreational crab fishers can also collect crabs by hand, but they primarily use traps (Florida Fish and Wildlife Conservation Commission, 2004a). A physical count conducted in the 1998-99 fishing season found 1.4 million traps, twice the number as was estimated in 1995-96 (Muller and Bert, 2001).

The biggest problem with with gear used to catch Stone crabs is ghost traps (traps that are lost at sea, usually because their surface buoys become detached). Ghost traps continue to catch Stone crabs and, to a lesser degree, bycatch until the biodegradable panel deteriorates. Deterioration of the panel can take from several months to a year. Ghost traps also cover the natural substrate. However, the traps eventually create "rocky bottom" when burried in sediment, or they're colonized by benthic organisms (Bert, Pers. Comm. 2004).

Stone crabs do not appear to have any particularly critical habitat areas. M. adina inhabit muddy bottoms, oyster reefs, seagrass flats, and to a lesser degree, rocky substrates. M. mercenaria inhabit mixed sandy/rocky substrates, and seagrass flats. Stone crab nursery grounds are located in mixed rocky/sandy bottoms, with some interspersed seagrass. Specific habitat types vary over the seasons. Overall, however, the range of habitat occupied by Stone crabs is rather huge, and extends into deeper waters over 80 feet. Everglades National Park protects a small portion of Stone crab habitat, but this area is not in place for Stone crab protection (Bert, Pers. Comm., 2004).

Habitat for Stone crabs is, for the most part, robust and viable. Unlike Blue crabs in the Chesapeake Bay, most of the Stone crab population lives in the ocean. While Stone crab recuitment grounds are nearshore and are more vulnerable to shore-based pollution, the region where Stone crabs largely occur is less exposed to industrial pollution or agricultural run-off, compared to bay areas (Bert, Pers. Comm., 2004).

There is management in place in both state and federal waters of the U.S. In Florida State waters, where the majority of fishing occurs, Stone crabs are regulated under Florida Administrative Code, Chapter 68B-13, and managed by the Florida Fish and Wildlife Conservation Commission (Muller and Bert, 2001).

Measures include gear controls for trap design (Muller and Bert, 2001), quotas for the number of crabs that can be caught as bycatch in other fisheries (Florida Fish and Wildlife Conservation Commission, 2004b), minimum size restrictions on claws (Florida Marine Research Institute, 2004), seasonal closure (Florida Fish and Wildlife Conservation Commission, 2003), a passive trap reduction program (Florida Fish and Wildlife Conservation Commission, 2003), prohibition on take a claw from an "ovigerous" (egg-bearing) female (Florida Marine Research Institute, 2004), and other measures.

Although there is currently no peer reviewed assessment to determine the health of the population, scientists and fishers believe that the population is heavily fished. The relative stability of catches seems to indicate that the population is relatively resilient and that the current management measures have some level of effectiveness. However, we awarded a score of 2 here because there is not enough information to assess whether management is preventing overfishing.

The lack of a statewide, fishery-independent sampling program has precluded examining the biological linkage between landings of claws and the underlying abundance of crabs (Muller and Bert, 2001). However, a Stone crab monitoring program is currently being put into place (Bert, Pers. Comm. 2004). Therefore no points were added or subtracted here.

Florida Stone crab populations are not considered to be overfished (Florida Fish and Wildlife Conservation Comission, 2003). However, there is no statewide stone crab monitoring program (Lollar, 2003), so no points are added here.

Stone crab fishers have pushed for stronger management of the Stone crab fishery. In an effort to reduce effort in the fishery, fishers asked regulatory agencies to implement a trap reduction program (Bert, Pers. Comm., 2004). On June 26, 2000, Florida adopted its trap certificate program, designed to reduce the number of traps in the Stone crab fishery to an optimal level over a 30-year period. This passive trap reduction program caps the number of traps and, eventually, will remove traps from the fishery, in an attempt to address a problem of overcapitalization in the Florida Stone crab fishery (Florida Fish and Wildlife Conservation Commission, 2003).

Most bycatch consists of sublegal Stone crabs, which are released alive without having a claw removed (U.S. National Marine Fisheries Service, 2001). The remaining bycatch is very small and when it occurs, is usually composed of juvenile or small fish, gastropods, hermit crabs, sand dollars, or sea urchins (Bert., Pers. Comm. 2004). Since there are no quantitative estimates available of bycatch in this fishery, we awarded a score of 2 here.

Most Stone crab fishers use wooden or plastic slated traps. Wire traps are commonly used in a few locations. Each wire trap must have at least three unobstructed escape rings (2 3/8” inside diameter) located on a vertical side of the trap as specified in rule, intended to minimize bycatch of finfish (U.S. National Marine Fisheries Service, 1999; Florida Fish and Wildlife Commission, 2004b). The more common plastic slate traps are required to have one biodegradable (wooden) panel. Should the trap become lost and turn into a ghost trap, it will eventually degrade to allow fish or other species free entry and exit (Bert, Pers. Comm., 2004).

Stone crabs are taken incidentally in Gulf Blue crab and Spiny lobster trap fisheries, but Stone crab claws removed from these fisheries are landed and legally sold. Thus, this catch is considered incidental catch, rather than bycatch (U.S. National Marine Fisheries Service, 1999). Consequently, no points were subtracted for this factor.