Osteichthyes are a taxonomic grouping of bony fishes. This group includes ray-finned fishes (class: Actinopterygii) and lobe-finned fishes (class: Sarcopterygii). This highly diverse group of fishes, which contains almost all fish species, is the most diverse group of vertebrates today. Osteichthyes differ from chondrichthyes by (in most cases) possessing a bony skeleton, a swim bladder, … [Read more…]
An oceanodromous fish, like an anadromous or catadromous fish, is a migratory fish. Unlike anadromous or catadromous fish, an oceanodromous fish spends its whole life in salt water. Many oceanodromous fishes are termed highly migratory species (HMS) because of their ocean basin-sized migration routes. Many HMS are high trophic level fish and they migrate in search of food in … [Read more…]
The terms overfishing and overfished are confusing because they address a similar subject. The difference between the two terms is subtle but significant. Overfishing refers to the current fishing rate which results in a higher harvest, or fishing mortality rate, than maximum sustainable yield (the maximum harvest level without negatively impacting the sustainability of the … [Read more…]
The operculum is a hard, plate-like, bony flap that covers the gills of a bony fish (superclass: Osteichthyes). It protects the gills and also serves a role respiration. Fish can acquire dissolved oxygen through pumping water over their gills by opening and closing their jaws and opercula. The water is flushed from the fish’s mouth over … [Read more…]
Otoliths are ear bones in fish. Bony fish (not sharks or rays) have three pairs of otoliths: Sagitta: detects sound and converts sound waves into electrical signals (i.e., hearing); Asteriscus: detects sound and is involved in hearing; and, Lapillus: detects gravitational force and sound. Sagittal otoliths are sometimes used for aging fish because they add … [Read more…]