Someone may tell you that you look “green around the gills” when you look ill but the expression doesn’t translate well to fish gills… No matter if a fish is sick or not, fish gills are often red – blood red, to be exact. That is because gills have blood vessels very close to their … [Read more…]
Trophic levels are a defined by the position of organisms in a food chain or food web. The different levels help define the flow of energy within an ecosystem. The lowest trophic level is primary producers, such as algae and phytoplankton, which generate their own energy from the sun via photosynthesis. Primary consumers, such as … [Read more…]
Aquaculture is defined by the Food and Agriculture Organization of the United Nations as the farming of aquatic organisms (e.g., fish, mollusks, crustaceans, plants) and harvest by an owner who is responsible for the maintenance, protection, and enhancement of the cultivated stock. Aquaculture is considered the fastest growing food production sector. In terms of global production, farmed … [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…]
Guest post by Emily Argo Each year adult salmon migrate upstream to spawn (lay eggs) putting into motion their offsprings’ journey from hatching to making their way back to the ocean as juveniles. In addition to being a spectacular event to witness, these migrations also play a central role in ecosystem health. Over 100 different … [Read more…]
Guest post by Emily Argo Countershading, originally described in the late 1800s, is when one side of an animal is dark and the other is light, serving as a form of camouflage. In fish, such as the Atlantic Bluefin Tuna (Thunnus thynnus) pictured, this typically means the ventral side (bottom) is light and the dorsal … [Read more…]
Phenology is the study of seasonal or periodic cycles in ecosystems. It is, essentially, “nature’s calendar.” For fish, phenology is often linked to timing of important life events such as spawning, migrations, and hatching. These events are triggered by non-biological factors like day length, temperature, and precipitation. If the timing of the main “cue” shifts, … [Read more…]
Panmictic refers to a random mating strategy, frequently employed by fish, where breeding is just as likely to occur between any two individuals in a population as between any two others. Mating in this way is not influenced by any any environmental (e.g., geographic proximity), hereditary (e.g., timing of spawning), or social interaction (e.g., polygamous mating … [Read more…]
T & E is an acronym for threatened and endangered. These are both status metrics for risk of extinction. Endangered species are considered on the “brink of extinction” throughout their range and threatened species are likely to become endangered in the near future. The species that are on this list in the United States receive … [Read more…]
A fish species is considered endemic to a location if that is the only place it occurs naturally. It may have evolved in that region or over time has become so adapted to that specific environment that it cannot survive elsewhere. For example, Devil’s Hole Pupfish (Cyprinodon diabolis) is only found in Devil’s Hole, Nevada. If a … [Read more…]