The Semaphore crab, Heloecius cordiformis: bio-indication potential for heavy metals in estuarine systems

Although alterations at the organism level in decapod crustaceans on exposu re to heavy metals have been evidenced in the laboratory, little examinatio n of metal effects on morphology and population parameters have been explor ed in a field-based situation. Relationships between morphological paramete rs, population demography and heavy metal sediment loadings were examined i n conjunction with the accumulation of metals in the Semaphore crab, Heloec ius cordiformis, in the Port Jackson and Hawkesbury River estuaries, Sydney , Australia. H. cordiformis exhibited sexual dimorphism, with males having larger carapace width, carapace length; chelae length and total mass than f emales. Sexes were subsequently treated separately to assess morphological differences among locations. Locations that had greater proportions of fema les with purple chelae and less females in the population tended to have hi gher sediment metal levels. These relationships were maintained over time, and could be employed as population-level biological indicators of heavy me tal stress. Copper and zinc were regulated in the hepatopancreas of H. cord iformis. Lead was accumulated in the hepatopancreas of H. cordiformis in pr oportion to sediment lead levels, suggesting the species is both an appropr iate candidate for bio-indication of lead pollution, and Pb is the main met al linked with population level differences. Accumulation of lead varied be tween sexes, indicating that sexes must be monitored separately. Smaller ma les accumulated more lead than larger males, suggesting size is an importan t consideration for lead accumulation. (C) 2000 Elsevier Science B.V. All r ights reserved.