Search results
Results from the WOW.Com Content Network
This type of polyandry was found throughout a variety of elasmobranch fish, or cartilaginous fish, such as sharks. [16] These sharks included lemon sharks, [17] sandbar sharks, [18] nurse sharks [19] and catsharks. [6] For convenience polyandry to occur, the costs of females resisting males must outweigh the costs of mating. [6]
The oldest case of viviparity in ray-finned fish is found in Middle Triassic species of †Saurichthys. [21] Viviparity is relatively rare and is found in about 6% of living teleost species; male care is far more common than female care. [20] [22] Male territoriality "preadapts" a species for evolving male parental care. [23] [24]
Myxosporea is a class of microscopic animals, all of whom are parasites.They belong to the Myxozoa clade within Cnidaria.They have a complex life cycle that comprises vegetative forms in two hosts—one an aquatic invertebrate (generally an annelid but sometimes a bryozoan) and the other an ectothermic vertebrate, usually a fish.
Fingerling – refers to a fish that has reached the stage where the fins can be extended and protective scales have covered the body. [4] At this stage, the fish is typically about the size of a human finger, [5] hence the name. Once reaching this stage, the fish can be considered a juvenile, and is usually active enough to move around a large ...
The discovery rate of siphonophore species was slow in the 18th century, as only four additional species were found. [11] During the 19th century, 56 new species were observed due to research voyages conducted by European powers. [11] The majority of new species found during this time period were collected in coastal, surface waters. [11]
The pectoral fins, usually with eight rays, may be large and well-developed to small and degenerate, or completely absent in a few species. In some species, such as those of the genus Lampanyctus, the pectorals are greatly elongated. Most lanternfish have a gas bladder, but it degenerates or fills with lipids during the maturation of a few species.
Fish embryos go through a process called mid-blastula transition which is observed around the tenth cell division in some fish species. Once zygotic gene transcription starts, slow cell division begins and cell movements are observable. [4] During this time three cell populations become distinguished. The first population is the yolk syncytial ...
Dactylogyrus species are monogenean parasites that are usually found on the gills of cyprinid fishes. [11] The prevalence of Dactylogyrus infection on fish differ depending on the seasons. It was found that Dactylogyrus infections are at their greatest during late autumn or early winter. [ 12 ]