The Biology Of Early Life Stages Of Fish Development

3a. Body more than five times as long as broad; front edge of dorsal fin far

The puffer fish reproduction method is unique. Puffer fish can begin reproducing starting at the age of five. Once the males have guided the female puffer fish to the shallow water or close to the shore and pushed the eggs to a certain place such as the water surface, the females lay eggs at the shore. She then will lay between 3 to 7 eggs. The shape of the eggs is typically like a sphere and float on the surface due to how light they are and their buoyancy. The young fish are protected by a hard egg shell. The babies typically hatch in approximately four days and no more than about a week.

Atlantic croaker larvae have a peak in spawning from July through December and an estuarine recruitment peak in October-November (Cowan, 1988; Ditty et al., 1988; Warlen and Burke, 1990; Barbieri et al., 1994a). Atlantic croaker spawn over a wide range of inner continental shelf depths, i.e., 54 m or shallower, with a portion of the population moving inshore towards the estuaries to complete spawning in the winter and early spring months (Barbieri et al., 1994a, 1994b). Hydrologic variability at large and small spatial and temporal scales can greatly affect the numbers of Atlantic croaker larvae able to successfully recruit to estuarine nursery grounds (Norcross, 1983; Shaw et al., 1988; Raynie, 1991; Raynie and Shaw, 1994). Once in the estuary, lower water temperatures in the first winter decrease survival, as verified in both the field (Norcross and Austin, 1988; Hare and Able, 2007), and laboratory (Lankford and Targett, 2001a, 2001b).

The life cycle of the Atlantic salmon begins in late October when rivers are just cool enough to begin production of the new salmon. The female starts by digging a small nest called a redd in the bottom gravel area of a stream. Reddd’s are built in a way that allows a clean flow and plenty of oxygen to be received by the growing fish. The male salmon then projects their milt (sperm) onto the redd to fertilize the egg. With swift movements made by the tail gravel is projected

In the laboratory exercise, two species of Gambusia (Gambusia speciosa and Gambusia krumholzi) were used in order to compare the fecundities of both species. It is proposed that, just like other vertebrates, there is a relationship between the sizes of a female their pregnancy status. Smaller fish would most likely be prepubescent and not able to reproduce. Larger females could have most likely gone through menopause and also not able to reproduce. Therefore, it is highly likely there are higher averages of pregnant fish at average sizes.

The essay’s overall structure is progressive. Fish polishes an idea, then moves to the next. This makes for a narrative-like prose that is clear and easy to follow, considering the complexity of the topic. In his sixth paragraph, Fish gets right to the point when he proposes that identity politics is unreasonable, but not meretricious. He provides an example: voting for a candidate based on their gender; saying, “‘because she is a woman as I am’ is of course a reason, but it is not reason of the relevant kind.” Fish then presents a scenario. A bold statement, followed by a plausible example is a recurring quality in Fish’s paper, posing uniformity and

Among this adaptation came the genome allowing for males to develop brood pouches and the ability to nurture embryos within these pouches, although seadragons and pipefishes carry their fertilized eggs in skin folds rather than a brood pouch (SFSU Geography and Dames N 2000). Early taxonomy described over one hundred different species of the Hippocampus genus and mistakenly designated names for members of the same species, meaning that the actual count of distinct species is far lower (SFSU Geography and Dames N 2000). The color-adapting nature of the seahorse made taxonomy quite difficult initially, but forced researchers to analyze the various species based upon other characteristics, such as body size or the number of rings on their prehensile tails (SFSU Geography and Dames N 2000). Recent research has narrowed the number of one hundred species down to a much more accurate and reasonable thirty two, with little debate as to the legitimacy of this figure (SFSU Geography and Dames N

They were obtained from fish that had been used to make breeding behaviour videos. The objective of these videos was to determine whether there were significant behavioural differences between WT and KO fish. The night before 20 tanks would be set up. Each tank contained one female and one male fish. Boxes and black plastic bags were used to keep fish in the dark until they could be filmed. Each video was ten minutes long. 80 tanks were filmed for SgIIa KO, SgIIb KO and WT fish respectively. Additional data obtained from the breeding experiment included the number of embryos produced, the number of unfertilized embryos as well as the number of dead embryos 6 hours post-fertilization (hpf). Once these results were recorded samples could be collected for ISH, the first taken at 6hpf after the dead embryos were counted. After that, samples were collected at 24, 30, 48, 72, 96 and 120 hpf. Each sample consisted of approximately 25 embryos or larvae that would be fixed in paraformaldehyde (PFA). After fixation embryos would be dechorionated and the samples would be dehydrated with methanol washes before being conserved in the -20˚C freezer until the student for whom the samples were collected could complete the remainder of the ISH protocol. Because at this age the fish are very small the procedure used was for whole

There has been studies done that focus on the reproductive morphology, mating behavior, and spawning ecology of two types of cephalaspid sea slugs (Aglajidae and Gastropteridae). There had been experiments done of four opisthobranch species that belong to the families of Aglajidae and Gastropteridae. Behavioral and morphological traits vary considerably between species, even closely related sister taxas. Also while they observed the species from each group

Osse et al., (1997) suggested that the differences in relative sizes of body parts and organs between newly hatched fish fry and post-metamorphic juveniles are due to growth priorities necessarily set during early larval

Mystery fish # 5 : This mystery fish is a steady swimmer because of its depressed fusiform body shape with a broad head, the presence of the depressed head shows it is sit and wait kind of predator. Its body shape shows it swims along the floor of the ocean. It has an emaciated caudal fin shape with a medium aspect ratio which reduces the drag. The fish has a stiffened 1/3 upper body as compared to the posterior part and also its tail is emarginated, therefore its mode of swimming is sub-carangiform.. The mystery fish #5 has an inferior mouth because the mouth is locate on flattened ventral side of the fish. To enable feeding it has a cardiform tooth which are numerous but small teeth found on the

The Stegostoma fasciatum (zebra shark) is an endangered species found in Indo-Pacific oceans1. The species has been observed for migratory behavior and in recent years, for cases of parthenogenesis- a form of asexual reproduction in which the embryos are not fertilized. The species reproduces sexually in its natural habitat. Cases of parthenogenesis have been observed in captive females, isolated from any males of the same species or related species. The switch from sexual reproduction to asexual reproduction has been observed in the absence of mates and stressful environments in several species such as Aetobatus narinari (eagle ray)2. The occurrence of parthenogenesis in captive S. fasciatum is likely a survival mechanism which ensures the development of future generations for evolutionary purposes.

Zebrafish is native to the southeastern Himalayan region (Burma, Nepal, India) and has its origin from the river Ganges in India. In most fish, growth (hypertrophy & hyperplasia) continues throughout life making them an important model for understanding the hormonal regulation of growth (Mommsen 2001). Zebrafish are useful in studies on the endocrinologic aspect of fish. The overall control of growth begins in the brain, although local factors in each tissues are also important. Growth hormone-releasing hormone (GNRH) is synthesized in nerve cells in the brain of Zebrafish as in other vertebrates. After secretion, GHRH binds its receptor on the surface of somtotroph cells in the anterior pituitary to release growth hormone(GH), which in

In late summer and early fall newts make one big growth; this is that they start to develop lungs and granular skin. In order to do that they need to absorb their gills and caudal fin. This is where they become terrestrial efts.

(A–C) Photographs of a D. longipes specimen in dorsal (A and B) and ventral (C) view. The yellow-orange eyeshine in the upward-looking, tubular eyes (A and B) and the eyeshine from the diverticulum (C) is from the camera flash. The black structures beside the main eyes (A and B) are the upper surfaces of the diverticula.