**8. Mercury and malformation in crabs**

In two recent studies, the impact that Hg can have on marine organisms was evaluated. The first is related to the high incidence rate of malformation in crabs collected in Cispatá Bay [19]. According to these authors, malformations occurred throughout the sampling year, fluctuating between 2.78% and 25.09% (**Table 5**).

**Figure 6** shows the malformations of two specimens of the Xanthoidea superfamily, multiple malformations are observed in both. In (A) malformations in the two anterolateral borders. (B) The left side shows the separated teeth, the fifth reduced, the third subquadrate projected posteriorly, and the first and second fused. (C) The


#### **Table 5.**

*Number of crabs of the superfamily Xanthoidea with deformities (No. D) and percentage in relation to the number of individuals collected (% D) of the superfamily, in three stations of Cispatá Bay, in four seasons of one year.*

*Mercury in the Colombian Caribbean: The Bay of Cartagena, A Model in Resilience DOI: http://dx.doi.org/10.5772/intechopen.107240*

#### **Figure 6.**

*Two examples of multiple malformations in crabs. (A) Dorsal view of a crab of the Xanthoidea superfamily. (B) Approach to the malformation of the right anterolateral border of the specimen. (C) Malformations in the abdomen. (D) Dorsal view of another crab of the superfamily Xanthoidea, the formation of the dactyl of the third left pereopod is observed. (E) Abnormal growth of the pleopods. (F) Malformation of the abdomen [19].*

deformed abdominal segments do not cover the abdominal cavity; the telson ends in a subtriangular shape, the right edge longer than the left. (D) Malformation of the dactyl of the third left pereopod and of the orbits and teeth of the right anterolateral border. (E) The right sternites, fifth and sixth, separated, and those of the left side completely fused. (F) There is an overgrowth of the appendages of the abdomen (pleopods) protruding and the abdomen is twisted to the right due to shortening of the right border of the sixth abdominal segment (**Figure 6**).

The highest incidence of malformations occurred during the sampling of June, with 55.8% of the total malformations and corresponds to the period immediately after the first rainy season (April-May). While the lowest incidence was determined in December, in the full dry season. In Punta Nisperal, crabs with malformations were collected throughout the three sampling periods and with a high prevalence (25.9% in June and 11.62% in March 2006). December was the only season in which specimens with malformations were captured, although with the lowest incidence (2.78%).
