Guest post: Gretchen Stokes, University of Florida Mouthbrooding is when fertilized eggs are carried and incubated in the parent’s mouth. Rather sophisticated for parental care in fishes, it may have evolved from lack of nest sites, predation or habitat invasion. It occurs in more than 53 genera of fishes. Mouthbrooding can be conducted by males (paternal), … [Read more…]
Maximum sustainable yield (MSY) is a classic concept from fish population dynamics. It operates under the assumption that populations have a carrying capacity, or equilibrium size, where the the resources available match the population requirements and if individuals are removed from the population, they will be replaced (i.e., are renewable). When harvest removes a portion … [Read more…]
Guest post: Emily Argo “I think you have a dead fish,” said a concerned aquarium visitor who summoned me to a nearby tank. Pointing to the tank the visitor recounted that they had been watching for a while and had not seen the fish move from it’s position on the bottom. The fish, I am happy … [Read more…]
Meromictic references a type of lake which is constantly stratified. The surface and bottom waters do not ever mix. In most cases, the bottom layer has very low oxygen levels, where few fish and other organisms can live, restricting them to the surface layer. Meromictic lakes are uncommon (most lakes are holomictic and turnover at least … [Read more…]
A meristic is a countable trait, such as number of gill rakers or number of dorsal fin spines. Morphometrics examines the size and shape using a measurable trait, such as standard length or wet weight, which can be gauged as a length, mass, angle or ratio of other measurements. Meristic traits and morphometrics are often used … [Read more…]
Monogamy is a mating system where partners live and exclusively mate with only each other. These pair bonds can be transitory, just for a single breeding season, extend for several years or even a lifetime. Fish that form strong pair bonds include: American freshwater catfish, some cichlids, and many butterflyfish. The Four-Eyed Butterflyfish (Chaetodon capistratus) is one such fish that mates … [Read more…]