This document is about Fish reproduction and the environment influence and endocrine cycle on fish reproduction, as well as mating systems

1. Breeding and hatchery
FISH REPRODUCTION
I. ENVIRONMENT INFLUENCE AND ENDOCRINE
CYCLE
II. MATING SYSTEM
ASSIGNMENT 1 PRESENTATION (GROUP C)
NAME REGISTRATION NUMBER
LAMIN N. CEESAY 230102164
SALAMA AMIRI. 230101949
YAMAMA CHAM 230102173

2. Introduction
 Reproduction varies across marine fish
species, although most fish have oviparous
reproduction.
 Understanding the environmental influences,
endocrine cycles, and mating systems in fish
reproduction is crucial for understanding their
adaptation and survival strategies.

3. Environment influence
& endocrine cycle
 Environmental influence and endocrine cycle are two
important factors that dictate fish reproduction.
 Various environmental factors, such as temperature,
daylight hours, water quality, and food availability,
contribute to the timing and success of fish reproduction
(Kumar et al., 2022).
 Pituitary gonadotropins secreting hormone is a key
regulator in fish reproduction (Yaron and Levavi-Sivan,
2011).

4. Environmental influence
Temperature:
 Water temperature significantly influences fish reproduction by affecting
metabolism and hormonal processes (Melo et al., 2022).
 Warm temperatures stimulate gonad maturation by regulating responses
to pituitary stimulation, thereby affecting gonadotropin synthesis and
release (B and S, 2017).
 For instance, Nile Tilapia reproduces year-round above 25°C, whereas carp
breeds between 24-31°C (B and S, 2017).

5. Cont…
Water currents and Rain
 Water currents, particularly during heavy rain, affect fish
electrolyte levels and stimulate natural spawning (B and
S, 2017).
 Species such as carp spawn in response to fresh
rainwater and flooded conditions, with optimal
spawning observed on cloudy and rainy days, especially
after heavy rainfall (B and S, 2017).
pH
 The ideal pH range for promoting growth and
reproduction is between 6.5 and 9, while values below 4
or above 11 can hinder growth and reproduction, and
even cause death due to acidity or alkalinity (Yokogawa,
2020).

6. Cont…
Salinity
 Different fish species have varying tolerances to
changes in salinity.
 For example, O. aureus and O. niloticus could be
cultured in low salinity brackish waters, between 3.6 and
14.5 ppt.
 Mozambique tilapia (O. mossambicus) can adapt to
salinities as high as 120 ppt, grow in ponds at salinities
from 32-40 ppt, and reproduce at salinities as high as 49
ppt (Alceste, 2017).
Endocrine Cycle
 Fish reproduction is regulated by pituitary
gonadotropin-releasing hormones (GnRH), such as
follicle-stimulating hormone (FSH), luteinizing
hormone (LH), estrogen, and testosterone (B and S,
2017).

7. Cont…
 The timing of social behavior is
regulated by environmental and
social cues, which activate the
hypothalamic-pituitary-gonadal-
axis.
 This activation promotes GnRH1
signalling in the pituitary gland,
leading to the release of the
gonadotropins LH and FSH.
 These hormones induce the gonads
to produce steroid hormones,
including androgens, estrogens,
and progesterones (Juntti and
Fernald, 2016).

8. Mating systems
 Mating systems are defined as the number of mating
partners an individual has during the breeding season
(Emlen & Oring, 1977).
Types of Mating System
The mating systems among fish are diverse, but the most
common types of mating systems in fish are as follows:
Promiscuous
 Both males and females spawn with multiple partners
over a short period of time (Emlen and Oring, 1977). E.g.
cichlids, herrings, guppies, armored catfish, humbugs,
and wrasses

9. Cont…
Polygamy
 In the polygamous mating system, one sex breed had multiple individuals.
Polygamy comes in different forms, such as polygyny and polyandry (Rios-
Cardenas & Morris, 2009).
Polygyny
 According to Emlen and Oring (1977) males have multiple female partners. E.g.
cichlid, sunfish, darter, damselfish, and sculpins

10. Con…
Polyandry
 Polyandry is a mating system in which one female
mates with multiple males.
 anemonefish and anglerfish
Monogamy
 In this mating system, fish live in pairs, stay together,
and mate or mate with the same individual repeatedly.
It is common among reef fish such as butterfly fish,
seahorses, North American freshwater catfish, cichlids,
airsac catfish, snakeheads, and gobies (Wong et al.,
2008).

11. conclusion  Fish reproduction is a vital process that ensures the
continuity of species.
 The process is influenced by environmental factors
and the endocrine cycle, which play crucial roles in
successful reproduction.
 Different species of fish have different mating
systems, with polygyny being the most common,
where males have multiple sexual partners.

12. Reference
 Allen, J.D. et al. (2017) ‘The effects of salinity and pH on fertilization, early development, and hatching in the crown-of-
thorns seastar’, Diversity, 9(1). Available at: https://doi.org/10.3390/d9010013.
 B, M.A. and S, S.N. (2017) ‘ROLE OF DIFFERENT FACTORS ON REPRODUCTION OF FISH’, pp. 86–93.
 Emlen ST, Oring LW. 1977. Ecology, sexual selection and evolution of mating systems. Science. 197:215–223.
 Juntti, S.A. and Fernald, R.D. (2016) ‘Timing reproduction in teleost fish: Cues and mechanisms’,
Current Opinion in Neurobiology, 38, pp. 57–62. Available at:
https://doi.org/10.1016/j.conb.2016.02.006.
 Rios-Cardenas, O. and Morris, M. (2009) ‘Mating systems and strategis of tropical fishes’, Tropical Biology and
Conservation Management, VIII(April). Available at: http://www.eolss.net/Sample-Chapters/C20/E6-142-TZ-
14.pdf.
 Wong, M.Y.L. et al. (2008) ‘Monogamy when there is potential for polygyny: Tests of multiple hypotheses in a
group-living fish’, Behavioral Ecology, 19(2), pp. 353–361. Available at: https://doi.org/10.1093/beheco/arm141.
 Yaron, Z. and Levavi-Sivan, B. (2011) HORMONAL CONTROL OF REPRODUCTION AND GROWTH | Endocrine
Regulation of Fish Reproduction, Encyclopedia of Fish Physiology: From Genome to Environment: Volume 1-3.
Elsevier Inc. Available at: https://doi.org/10.1016/B978-0-12-374553-8.00058-7.
 Yokogawa (2020) 'pH in Fish Farming' Accessed 18th February 2024 from
https://www.yokogawa.com/library/resources/application-notes/ph-in-fish-farming/