Reproduction is one of the important physiological systems that are important in the life cycle of living organisms including fish. The main objective of the reproduction is to maintain the existence of the species and therefore fish has a strategies and tactics to achieve this objective. The reproduction behaviours are important to be studied in relation to know the population dynamic of fishes and their spawning seasons. This information is very crucial in relation to the development of breeding technology for aquaculture and conservation (restocking) purposes. This paper reviews the reproductive strategy, fecundity and spawning frequency of fishes. Studies on reproductive behaviour of fish are important and a basic requirement for improvement and effective fishery resources management and conservation (Ali & Kadir, 1996; Ezenwaji et al., 1998; Brewer et al., 2008; Grandcourt et al., 2009), determination of basic life-history information and for assessing the impacts of environmental variability on the dynamics of fish populations (Schlosser, 1990). Information on the reproductive system is essential for the development of the commercial aquaculture of an aquatic species (Muchlisin, 2004). Natural challenge leads the fish to the maximization of the lifetime production of offspring, and more importantly to maximization of survivorship of offspring until adulthood (Murua & Sabodiro-Rey, 2003). Herein, we reviewed some aspects of reproductive biology of fishes such as reproductive strategy, fecundity and spawning frequency. The reproductive strategies of fishes are often reflected in the anatomical differences between the sexes, male and female. The objective of a reproductive strategy is to maximize reproductively active offsp... ... middle of paper ... ...ed to produce fewer eggs (Matthews, 1998). In species whose eggs develop in open waters or are freely scattered on the bottom, population strength is usually maintained by high fecundity relative to the small egg size. Development of adaptations for care of progeny is accompanied by decreased fecundity and usually increased egg size with greatly increase energy resources for embryo and enables the embryo to develop without obtaining exogenous food, and to reach active life at a higher level of differentiation and ensuring higher survival (Ginzburg, 1972). On the other hand, the relative fecundity is based on weight of fish. In most fish the number of eggs does not change significantly as the season progresses and the relative fecundity is constant through the season (Bagenal, 1978). For comparison fecundity among fishes, the relative fecundity is commonly used.
Since three-forth of the world is composed of bodies of water, it’s natural that a great number of people rely on fishing for their livelyhood or just for their recreation needs. There are numerous of fish species swimming under the lakes, seas, ponds, and rivers. Most anglers consider fishing as the delight in their purpose-driven life, a sport, as they say.
The Longnose gars reproduction depends on location that the gar is found in. The reproduction does typically happen during the spring or summer months and all dependent on what the water temperature. The female gar will swim into a small, fast moving stream and lay their eggs (Goddard). The Longnose gar eggs are not just normal eggs that most people think of when they think of fish eggs. Their eggs are green and sticky so they can stick to the plants in the fast moving stream (
The female reproductive system in birds is reduced in most species to a left ovary and oviduct. This unilateral reduction of the female reproductive system is thought to bear two benefits: it reduces the female’s body and it prevent the potential problem of simultaneously carrying two large fragile eggs within the abdominal cavity. It also balances the body with the liver on the right side adjacent to the left ovary.
The courting ritual begins with the males circling females in an offshore mating ground and then the males approach and bite a female’s neck and if she accepts, they mate; if she does not accept, she swims to the bottom of the mating grounds (Deurmit L 2007). Males have long claws to use during mating because other males try to remove the mating male in order to mate with the female (Deurmit L 2007). Caretta caretta are polygynandrous and breed seasonally in the early summer (Deurmit L 2007). With mating, the females have the ability to store sperm throughout the reproductive season (Sakaoka K et al.). This characteristic developed with “changes in the sperm storage tubules (SSTs) in the oviduct” and allows the females to reproduce more (Sakaoka K et al.). This storage helps to combat climate change because Caretta caretta, as a species, only breed during certain temperatures (Sakaoka K et al.). Female loggerhead turtles have developed sperm storage abilities within mating to combat climate
Reproduction: The Redfin pickerel spawns in the early spring as water temperature approach 50°F. Spawning occurs in shallow water when the female deposits her eggs in vegetated areas where they are fertilized and left unattended. A large female may deposit as many as 4,000 eggs at one time. Some fish as small as 5 inches may release no more than 400 eggs. They become sexually mature by at least age two. No parental care is given to the eggs.
Social reproduction is the reproduction of cultural, human, and social capital in society. Therefore languages, traditions, cultural values, education, food security, and social circles are passed down from one generation to the next through Karl Mannheim’s concept of “fresh contact” and through society as a whole. Social reproduction is effective when social structures and equality within society are maintained. Inequality, poverty, and social changes that force society to adapt can impede the process of social reproduction causing what is known as a “crisis in social reproduction” (Wells, 2009). Born into Brothels demonstrates a crisis of social reproduction that negatively impacts the lives of children living in Sonagachi as a result of globalization, neoliberal policies, poverty, lack of adequate education and social structures to pass down capital, and the stigma of prostitution. Additionally, it shows the need for children to make economic contributions to their families that prevent them from leaving the brothel.
Gender stereotypes have existed since the beginning of modern man. We've all heard them before; male dominance and female weakness, a controlled male and a flustered female, aggression and passion, and many others that all basically boil down to the same thing. Emily Martin, in her essay entitled The Egg and the Sperm, takes this problem of gender stereotype to a new and much more serious level. As an anthropologist, Martin is concerned with the socio-cultural impacts on many different aspects of everyday life, including biology. In doing her research for this article, Martin was trying to uncover suspicions she had about socio-cultural gender stereotypes, and the affects they had on the diction used to describe egg and sperm interactions in numerous biology books and research reports.
At first glance, assisted procreation practices do not necessarily violate a child’s right to identity. The violation lies in the fact that the state is not taking a serious enough stance on regulating the issues that emerge from assisted procreation technologies. The state is voluntarily removing its responsibilities in regulating this field by allowing cases of donor confusion, the implantation of too many embryos and the disorganization of donor files. Instead of imposing criminal sanctions or punishments, the state is too often turning a blind eye.
Ritchie, Anna. Isabella. (2015). The 'Secondary' of the 'Secondary' of the 'Secondary' of the 'Secondary' of the 'Secondary' of the 'Secondary' of the 'Second Quote investigator, WordPress, Retrieved from http://quoteinvestigator.com/2015/08/28/fish/, web. Toal, Robin. a.
However, only a small percentage of salmon live to reach their natal stream or spawning grounds. Those males that survive the trip are often gaunt, with grotesquely humped backs, hooked jaws, and battle-torn fins. The females are swollen with a pound or more of eggs. Both have large white patches of bruised skin on their backs and sides.
Meiosis is a specialized form of nuclear division in which there two successive nuclear divisions (meiosis I and II) without any chromosome replication between them. Each division can be divided into 4 phases similar to those of mitosis (pro-, meta-, ana- and telophase). Meiosis occurs during the formation of gametes in animals.
Overfishing is the most major problem related to oceans, but it is also the most overlooked. Fishing has been going on for thousands of years, and fish have always been seen as a renewable resource, that would replenish itself forever for our benefit. But around the world there is evidence that fish are not recove...
Grier, James W. and Theodore Burk. Biology of animal behavior: Reproductive behavior; Sexual reproduction and sexual selection. p. 318 - 358. 6th ed. 1984 Wm. C. Brown Communications, Inc. Iowa.
It is largely speculated that the ratio of male to female whale sharks dictate the structure of their mating system (Martin 2007). Rhincodon typus are oviparous giving birth to live young and have been documented to carry up to 300 embryos at one time. Female whale shark’s will give birth to numerous batches of pups in short succession and may rest up to a year after giving birth before mating again. The large size of the litter and rate of birth suggests a very high rate of neonatal mortality. Young pups will stay with their mother for an undetermined amount of time until they are