Herbivory

Herbivory

Three Types of Herbivorous Fishes

Longfin Damselfish-Juvenile

There are three types of herbivorous fishes. These include territorial grazers, roving grazers, and scrapers.. Territorial grazers are site-attached fish that actively defend their territories against other herbivores. One example of a territorial grazer is a damselfish.

Roving Grazers are mobile herbivorous fish that move around reefs in large schools. These fish feed on macro algae and epilithic algae, or algae that is found on stone. How about an example that we saw? The last type of herbivorous fish are scrapers. Scrapers are highly mobile fish that consume epilithic algae and remove sediment by scraping limestone surface of reefs. A few examples of herbivorous fish include surgeonfish, butterflyfish, angelfish

Feeding Habits of Herbivorous Fish/How Food is Digested

Blue Parrotfish

Pharyngeal teeth

Herbivorous fish feed on enriched macrophytes. Shallower reefs have more herbivorous fishes and increased grazing rates as compared to deeper parts of the ocean. Some herbivorous fish prey directly on corals. Parrotfish are an example of fish that prey directly on coral.

Typically, herbivorous feed on red, green, and brown macro algae They do not have teeth in their jaws, rather pharyngeal teeth positioned farther back in their mouth/ throat region.

For digestion in herbivorous fish, the goal is to break down the complex polysaccharide cell wall of the algae, etc. that the fish ingest. The breakdown of the complex polysaccharide wall can be accomplished by mechanical, chemical, or enzymatic stress. The goal of mechanical digestion is for the stomach to grind the algal cells. This is done using a pharyngeal mill or gizzard-like stomach that breaks down the cell wall. In chemical digestion acid lysis is used in the cells of the stomach. For enzymatic digestion, enzymes produced by the gastrointestinal tract can further break down algal cells and intestinal microbes that are otherwise unusable polysaccharides. These enzymes have the ability to convert the polysaccharides into organic molecules that the fish are able to use.

Benefits of Herbivore Fishes to Stability of Coral Reefs

Herbivorous fish help the ecosystem by maintaining coral-dominated states. They maintain the coral-dominated states by limiting growth of macro algae that competes with coral space. This has been proven to be beneficial, because studies have shown that a decrease in herbivorous fish can be linked to an increase in macro algae and coral reef mortality. Macroalgae and phytoplankton are the most significant primary producers in a coral system. Therefore, herbivorous fish essentially facilitate the maintenance of reefs in coral dominated states. As a result, herbivorous fish exhibit strong top-down control of macroalgae. Elimination of herbivorous fish can negatively impact survival, growth, and recruitment of corals and increase the prevalence of coral diseases and mortality. Alteration in consumer pressure, meaning a decrease in herbivorous fish, will reduce coral reef resilience and increase probability that climate change, ocean acidification, etc. will drive reefs to state like algal domination. This is an awkward sentence Turf algae and upright macroalgae increases, for instance, are due to herbivore exclusion. One of the most well-known cases of overgrowth occurred in the Caribbean after a previously unseen disease virtually killed off the herbivorous sea urchin Diadema antillarum. The death of the sea urchin caused the collapse of Caribbean reefs in this area, allowing macroalgae to become dominant. Ultimately, this led to a decrease in diversity which increases the danger climate change, etc.Fix this last sentence