broodstock

Broodstock , or broodfish , are a group of mature individuals used in aquaculture for breeding purposes. Broodstock can be a population of animals maintained in captivity as a source of replacement for, or enhancement of, seed and fry numbers. [1] These are maintained in such photoperiod , temperature and pH are controlled. Such populations are often subject to maximum fry output. Broodstock can also be sourced from wild populations where they are harvested and held in maturation tanks before their seed is collected for grow-out to market size [2]or the juveniles returned to the sea to supplement natural populations. [1] This method, however, is subject to environmental conditions and can be unreliable seasonally, or annually. [2] Broodstock management can Improve seed quality and number through enhanced gonadal development and fecundity . [3]

Management

Broodstock management involves helping to increase the survival rate, increase growth and increase fecundity. [3] Such conditioning is necessary to ensure the sustainability of aquaculture production, [4] and to increase the number and quality of eggs produced and the timing of maturation and spawning . [5]Management of the technologies for gamete production in captivity is one of the essential steps for aquaculture that would ensure the growth to this sector. Unfortunately, most fish in the captivity condition, exhibit some degree of reproduction dysfunction. Many species of captive fish are able to reach reproduction in normal conditions and gonadal growth occurs normally. However, some of the female species often fail final oocyte maturation stage. [6]Hormonal handling and acceleration of final maturation is important. For instance, in Salmoniformes, the need to collect the eggs by stripping is a serious limitation, while the time of ovulation can be predicted with accuracy, as over-ripening may take place in minutes or hours after ovulation [7] Therefore, control of reproductive broodstock is essential for the sustainability of commercial aquaculture production [8]

Choosing species to use requires consideration of the biology of the species. This includes their size at maturity, method of reproduction, feeding behavior and ability to tolerate adverse conditions. [9] Farms also consider whether they grow their own broodstock or obtain them from natural populations. Where natural populations are excluded, the farm can be considered a self-sustaining unit of independent genetic influence. [10]

Pond-reared broodstocks are selected, often juveniles, and grown out in suitable conditions to sexual maturity. These animals require stable, well-balanced, species-dependent, protein rich diet. [9] This enhances the germinal tissue for future seed stock as it is formed in juveniles. [9]

The pond or tank in which the broodstock is held. [11] Dependent on the species involved. [11] Where does it come from? For example, male and female Sturgeons sponds to different hormone levels, [12] this aussi Allows more control over eggs and sperm.

The characteristics of the water in which the mature broodstocks are held must be manipulated. The aquaculturist must consider the appropriate oxygen concentration, temperature, and pH of the water [4] [9] [13] .

The feeding regime of broodstocks is species specific [10] and requires consideration of timing and composition of food. [3] Protein , lipid and fatty acid composition is particularly important. [3] The quantity of food intake can be altered to spawning and maturity, for example low rations have been shown to reduce the number of fish reaching out to the growing population of those who do. [5]

When fry are desired, spawning can be induced by the manipulation of environmental factors. In particular the photoperiod can be altered to imply that it is time to spawn. [4] A shortened photoperiod is known to advance spawning times while a lengthened photoperiod can delay spawning. [14] Artificial light can be used to change the seasonal and other aspects [5] Water temperature can be increased for the same purpose. [4] Following spawning the female broodfish are often stressed and have lost weight. They require extra care and abundant feeding at this time to ensure the survival of the next spawning season.

Advantages

Managers can provide for the development of nutrients, which can be used in the production of nutrients and other nutrients. [5] [15] This is further possible in which populations can be selected for over generations, for higher fecundity. [5]

The breeding season and spawning times can be shifted by expanding the seasonal range of production. This leads to more efficient aquaculture because it is available to the market year round. [5] Hormonal treatments can advance spawning by two to three weeks. [5] Manipulating photoperiod can alter spawning time. [5]

Broodstock managers may use or select for traits such as [15] This Ability for genetic improvement of stocks is more efficient and Produces Higher value stock. Broodstocks also enable you to selectively plan and control all matings. Selective breeding is an important part of the domestication of aquaculture species.

Pond-reared broodstocks benefit from the removal of predation which can be a significant cause of mortality in natural populations. [16] They further benefit from the removal of variable environmental impacts.

Holding broodstock in an accessible pond or tank

Disadvantages

When broodstocks are used to supplement natural populations they face different. [1] Thus, they may not have adequate fitness to survive the natural environment, or may alter and reduce the size of the population. [1]

Broodstocks require supplementation from outside sources regularly to prevent negative effects of closed populations. Domestication of broodstocks in hatcheries can reduce reproductive capabilities [16] and alter other genetic characteristics. [16] For example, a trout stock maintained as a closed population for 20 generations Showed Reduced number and size of egg production. [17]

Examples

Penaeidae

Shrimp, particularly of the family Penaeidae , are one of the largest internationally traded species. [18] Native stocks are usually collected as sources of broodstock supply. [18] [19] There are also examples of pond-reared Penaeidae broodstocks. [2] These shrimp are raised in a suitable environment for a 12-14 hour / day photoperiod, at a water temperature of 25-29 ° C and full seawater salinity with high water exchange rates. [19]

Sydney rock oyster

The Sydney rock oyster , Saccostrea glomerata , has been farmed in New South Wales, Australia for over 100 years. [20] Due to Declines in the supply in the past 30 years, [20] New South Wales Introduced a selection program in 1990 to breed faster growing stocks. [21] The use of broodstocks are held in artificial ponds of around 0.11 ha in size, and at low densities. [22] Broodstocks Provided Higher numbers of larvae and spawned Could Be Readily supplier providing a more definite source of Sydney rock oysters. [22]

Rainbow trout

Global production of rainbow trout , Oncorhynchus mykiss , requires over 3 billion eggs per year. [5] This number is because of broodstocks which undergoes selection and conditioning in hatcheries. [5] Trout have been reared artificially for over 80 years. [23] Rainbow trout broodstocks are commonly manipulated to delay maturation and spawning time in order to provide eggs regularly and optimizes supply. [5] Artificial selection has favored larger fish due to evidence of correlation between fish size and fecundity. [15]

References

  1. ^ Jump up to:d Waples, RS, and C. Do. 1994. Genetic risk associated with supplementation of Pacific salmonids: Captive broodstock programs. Canadian Journal of Fisheries and Aquatic Science, 51 (1), 310-329.
  2. ^ Jump up to:c Fast, AW (1994). Effects of broodstock size and source on ovarian ripening and spawning on Penaeus monodon Fabricius from the Gulf of Thailand. Journal of the World Aquaculture Society, 25 (1), 41-49.
  3. ^ Jump up to:d Izquierdo, MS, Fernandez-Palacios, H. And Tacon, AGJ (2001). Effect of broodstock nutrition on reproductive performance of fish. Aquaculture, 197, 25-42.
  4. ^ Jump up to:d Mylonas, DC, Fostier, A. And Zanuy, S. (2010). Broodstock management and hormonal manipulations of fish reproduction. General and Comparative Endocrinology, 165 (3), 516-534.
  5. ^ Jump up to:k Bromage, N., Jones, J., Randall, C., Thrush, M., Davies, B., Springate, J., Duston, J. and Barker, G., (1992), Broodstock management, fecundity, egg quality and the timing of egg production in the rainbow trout (Oncorhynchus mykiss). Aquaculture, 100, 14.
  6. Jump up^ Yousefian, M., Mousavi, SE (2011). The mechanism of reproduction and hormonal function in finfish species: A review. Scientific Research and Essays, 6 (17), 3561-3570.
  7. Jump up^ Mousavi, SE (2013). Hormonal induction and synchronization of ovulation in endangered Caspian brown trout (Salmo trutta caspius Kessler, 1877) and its effect on egg quality. Journal of current research in science, 1 (4), 192-198.
  8. Jump up^ Yousefian, M., Mousavi, SE (2011). A review of the control of reproduction and hormonal manipulations in finfish species. African Journal of Agricultural Research, 6 (7), 1643-1650.
  9. ^ Jump up to:d Demoulin, F. (1999). Guidelines for broodstock and hatchery management; Support for technical services. Food and Agriculture Organization of the United Nations, Bangkok.
  10. ^ Jump up to:b Hussain, MG and Mazid, MA (1999). Broodstock management and some suggestions to control negative selection and inbreeding in hatchery stocks in Bangladesh. The ICLARM Quarterly, 22 (4), 24-27.
  11. ^ Jump up to:b Helm, MM, Bourne, N. and Lovatelli, A. (2004) .Hatchery Culture of bivalves: A practical manual. Food and Agriculture Organization of the United Nations, Rome.
  12. Jump up^ Perry’s Semenkova, T., Barannikova, I., Kime, DE, McAllister, BG, Bayunova, L., Dyubin, V. and Kolmakov, N. (2002). Sexual steroid profiles in male and female stellate sturgeon (Acipenserstellatus Pallas) during final maturation induced by hormonal treatment. Journal of Applied Ichthyology, 18, 375-381.
  13. Jump up^ Moorhead, JA and Zeng, C. (2011). Breeding of the forktail blennyMeiacanthus atrodorsalis: Broodstock management and larval rearing. Aquaculture, 318, 248-252.
  14. Jump up^ Prat, F., Zanuy, S, Bromage, N. and Carrillo, M. (1999) Effects of constant short and long photoperiods on the spawning performance and sex steroid levels of male and female sea bass. Journal of Fish Biology, 54, 125-13.
  15. ^ Jump up to:c Bromage, N., Hardiman, P., Jones, J., Springate, J., and Bye, V. (1990) Fecundity, egg size and total egg volume differences in 12 stocks of rainbow trout, Oncorhynchus mykiss Richardson. Aquaculture and Fisheries Management, 21 (3), 269-284.
  16. ^ Jump up to:c Berejikian, BA (1995) The effects of hatchery and wild ancestry on the relative ability of steelhead trout fry ( Oncorhynchus mykiss ) to avoid a benthic predator. Canadian Journal of Fisheries and Aquatic Sciences, 52, 2476-2482.
  17. Jump up^ Gall & Gross, 1978
  18. ^ Jump up to:b Anyanwu, PE, Ayinla, OA, Ebonwu, BI, Ayaobu-Cookey, IK, Hamzat, MB, Ihimekpen, AF, Matanmi, MA, Afolabi, ES, Ajijo, MR and Olaluwoye, BL (2011 ). Cultivation possibilities of Penaeus monodon in Nigeria. Journal of Fisheries and Aquatic Science, 6 (5), 499-505.
  19. ^ Jump up to:a Peixoto B , S., Wasielesky, W., Cavalli, RO (2011). Broodstock maturation and reproduction of the indigenous pink shrimp Farfantepenaeus paulensis in Brazil: An updated review on research and development. Aquaculture, 315, 9-15.
  20. ^ Jump up to:b Troup, AJ, Cairns, SC and Simpson, RD (2005). Growth and mortality of sibling triploid and diploid Sydney rock oysters Saccostrea glomerata(Gould), in the Camden Haven River. Aquaculture Research, 36 (11), 1093-1103.
  21. Jump up^ Nell, JA, Smith, IR and McPhee, CC (2000). The Sydney rock oysterSaccostrea glomerata(Gould 1850) breeding program: progress and goals. Aquaculture Research, 31, 45-49.
  22. ^ Jump up to:b Maguire, GB, Wisely, B. and Skeel, ME (1981). Cultivation of the Sydney oyster rock Crassostrea commercialis (Iredale and Roughley) in prawn farming ponds. Aquaculture, 24, 63-75.
  23. Jump up^ Gall, GAE and Gross, SJ, 1978. A genetics analysis of the performance of three rainbow trout broodstocks. Aquaculture, 15, 113-127.

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