Herbivorous crabs

Stachowicz JJ, Hay ME (1996) Facultative mutualism between an herbivorous crab and a coralline alga advantages of eating noxious seaweeds. Oecologia 105 377-387 Stachowicz JJ, Whitlatch RB (2005) Multiple mutualists provide complementary benefits to their seaweed host. Ecology 86 2418-2427... 

Kennish, R., Diet composition influences the fitness of the herbivorous crab Grapsus albolineatus, Oecologia, 105, 22, 1996. 

Many species of animals, including lobsters, detect and react appropriately to chemicals from predators. For example, Wahle (1992) showed that American lobsters exposed to chemicals from a predatory fish spend significantly more time in their shelters than control animals, and Homer et al. (2006) showed thatP. argus tends to avoid the scent of a predatory octopus. Hermit crabs are even able to discriminate between predatory and herbivorous crabs by their scent alone (Rosen et al. 2009), although we know of no comparable lobster-specific data. 

Bivalve shellfish, primarily scallops, mussels, clams, oysters, and cockles Specific herbivorous fish and crabs... 

The impact of marine food is directly proportional to the rate of consuming each level of marine food chain. For example, the phytoplanktons, seaweeds/grasses are consumed by the next level of ecological pyramid, the herbivores, which consists of zooplanktons, parrot fish, oyster, shrimp, clams, crabs scallops, tilapia, lobster, etc. Oceans carnivores... 

Herbivores in the sea are phylogenetically more diverse than on land. Seaweeds are eaten by diverse vertebrate ectotherms and an array of invertebrate consumers that vary both in their selectivity and in their impact on algae. Vertebrate herbivores are comprised of various fish families and species, as well as some turtles.24 111 120 125 Invertebrate herbivores span at least four different phyla and include an array of gastropods (such as snails, limpets, sacoglossans, sea hares, cephalaspideans, and chitons), urchins, crabs, amphipods, isopods, shrimps, polychaete worms, copepods, and a few insect species that feed on algae living in the upper littoral zone.24 110 123 126-135... 

Exposure is mainly through food but also a direct uptake from water is also evident for aquatic organisms. This means that organisms exposed to even moderately elevated cadmium levels will bioaccumulate the element very effectively significantly elevated levels are found, for instance, in kidney and liver tissue from wild herbivorous animals such as the elk (Alces aloes ) and in the hepatopancreas of marine crustaceans such as the lobster (Homarus gammarus) and the crab (Cancer pagurus). 

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