Autotomy in Blue Crab (Callinectes sapidus Rathbun) Populations: Geographic, Temporal, and Ontogenetic Variation

Abstract

Abstract. Blue crab (Callinectes sapidus Rathbun) populations were examined at four sites in Chesapeake Bay and three additional sites along the southeastern Atlantic coast and Gulf of Mexico; the aims were to assess the incidence of limb autotomy and to determine whether injury patterns varied temporally, geographically, and ontogenetically. These data, which include four years of information from one site (Rhode River, Maryland, a subestuary of central Chesapeake Bay), make this study the most extensive and intensive survey oflimb autotomy yet conducted in arthropods. A substantial percentage (17-390/0) of the blue crab populations were either missing or regenerating one or more limbs, suggesting that autotomy is an important mechanism for their survival. The frequency oflimb autotomy varied, both within and between years, and over broad geographical scales. Injury levels were generally correlated positively with crab size. Limb autotomy was independent of sex and molt stage, and frequencies varied little among sites in the Rhode River. Patterns of limb injury in C. sapidus were remarkably consistent among all sites. The most frequent injury involved loss of a single cheliped. Swimming legs suffered the least damage. Severe multiple limb loss was rare. Right and left limbs 'were lost with equal frequency in most populations. This consistency of autotomy pattern suggests differential vulnerability of limbs and standard behavioral response by blue crabs to various injury-causing agents. The frequency of autotomy was density-dependent in the Rhode River, indicating that intraspecific interactions (e.g., cannibalism) may be a major cause of limb Received

Incidence of Limb Loss and Bald Chelipeds in the Japanese Mitten Crab Eriocheir japonica (de Haan) in its Marine Phase

“…Within the same species, the increase in the relative size of chelipeds caused by their positive allometric growth may raise the frequency of injury to chelipeds in large crabs. Differences in the utilization of each limb in encounters are also an important factor (Smith & Hines 1991) . Among grapsids, touches using the walking legs occur during intraspecific encounters (Warner 1970;Abele et al 1986).…”

Distribution of barnacle epizoites of the crab Portunus pelagicus in the Moreton Bay region, eastern Australia

“…The dorsal and ventral surfaces of all crabs were examined for barnacles with the number of each species recorded. Barnacles that settled on other appendages were not counted or analysed due to the geographic and temporal variation of limb autonomy in portunid crabs (Smith and Hines 1991). Parasitism of crabs by the rhizocephalan Sacculina granifera was staged according to the methodology of Sumpton et al (1994a).…”

Foraging and agonistic activity co-occur in free-ranging blue crabs (Callinectes sapidus): observation of animals by ultrasonic telemetry

“…In blue crabs, the degree to which threat behavior is ritualized has not yet been quantified; however, it is apparent that outright combat is frequent when crab density is high (Smith, 1990;Mansour and Lipcius, 1991;Smith and Hines, 1991). Consequences of aggressive interactions among crabs can be serious in terms of physical damage and energy loss (Smith, 1990;Smith and Hines, 1991;Smith and Taylor, 1993;Juanes and Smith, 1995;Smith, 1995), and -when there is a large size differential between combatants -even fatal (Dittel et al, 1995;Hines and Ruiz, 1995).…”

“…Once on a patch, they generally remain there long enough to consume multiple prey (Nye, 1989;Wolcott and Hines, 1989). Both laboratory studies and indirect field evidence indicate a high level of intraspecific agonism as crab density increases (Smith, 1990;Mansour and Lipcius, 1991;Smith and Hines, 1991). Under laboratory conditions, these aggressive interactions among crabs impair foraging success (Mansour and Lipcius, 1991;Dittel et al, 1995;Hines and Ruiz, 1995).…”