COMPARATIVE STUDIES ON THE BREEDING BEHAVIOUR AND ITS RELEVANCE IN CULTURE PRACTICES OF TWO INTRODUCED CICHLIDS

Shubha M¹ and S Ravichandra Reddy²

¹ Asst. Professor, Department of Zoology, BMS College for Women, Bengaluru, INDIA.

² Professor of Fishery (Retd), Bengaluru University, Bengaluru, INDIA.

*Corresponding author: shubhabhat21@gmail.com

Reproductive strategies are highly variable in Cichlid fishes. They are known for their complex reproductive behaviour with different mating behavior comprising mate selection, territorial defense and parental care. Present work provides detailed information on the reproductive behavior and parental care in Nile tilapia Oreochromis niloticus (Linnaeus 1758) and in Salvini cichlid Cichlasoma salvini (Gunther 1862) introduced in India for culture (former) and ornamental (latter) purposes. Experiments in both species were conducted in 18X10X24"size glass aquaria provided with sand particles and hiding places. Fish were fed on fish food pellets and Tubifex tubifex worms. Reproductive behavior in either species of fish could be categorized into pre-spawning, spawning and post-spawning phases. In pre-spawning phase, only male O.niloticus constructed the nest in the bottom sand while that in C.salvini both male and female were involved in construction of nest. Males in either species with various body movements attract the breeding female towards spawning site. In spawning phase, both in O.niloticus and C.salvini females spawn in the centre of the nest and males swim over the eggs to fertilize them. Soon after male O.niloticus fertilizes eggs, female takes eggs into oral cavity and initiate mouth brooding. On the other hand in C.salvini male after fertilizing eggs, retreats and starts defending the territory, while female stays close to the eggs and uses her pectoral fins to fan the eggs with water. In post-spawning phase, female O.niloticus leaves nest and swims with other fishes. Females roll the eggs for oxygenation. C.salvini female continues to stay close to the eggs and leaves the site temporarily for feeding. During this time male takes her place. These reproductive traits suggest O.niloticus is uniparental and C.salvini is biparental. In the light of these observations, requirement of spawning beds/areas in culture practices are discussed.

Keywords: Cichlid fish, reproductive behavior, parental care.

EFFECT OF BODY SIZE AND WILD OR INDUCED MATING ON THE REPRODUCTIVE PERFORMANCES OF FEMALES OF ORANGE MUD CRAB, Scylla olivacea (HERBST, 1796)

Mohammad Asmat-Ullah1, Khor Waiho1, Hanafiah Fazhan1,3,4, Mohd Husin Norainy1, Sk Ahmad Al Nahid2, Hongyu Ma3,4, Mhd Ikhwanuddin1,4*

1Higher Institution Centre of Excellence (HICoE), Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, Kuala Nerus, 21030, Terengganu, Malaysia 2Department of Fisheries Resource Management, Chattogram Veterinary and Animal Sciences University, 4225, Chattogram, Bangladesh

3Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, China

4STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China

*Corresponding author: ikhwanuddin@umt.edu.my

Induced breeding of mud crabs is the key to year-round seed production for this commercially important crustacean species. This study was executed to select the female broodstock size based on its reproductive performances (spawning, egg fertilization and hatching success) for the seed production of Scylla olivacea through induced mating. Induced mated and wild mated females were categorized into two groups (carapace width (CW) < 100 mm and CW ≥ 100 mm) and used in captive breeding. Unilateral eyestalk ablation was done to the mated females for the induced spawning in captivity. The induced mating technique successfully obtained berried females in captivity with 95.25 ± 0.35% and 90.88 ± 0.98% (mean ± standard error) egg fertilization and hatching rate, respectively. This study showed that larger sizes (CW ≥ 100 mm) of mated females were suitable for the larvae production of S. olivacea in captivity.

Keywords: Crustacean aquaculture; Molting; Sexual maturity; Eyestalk ablation; Breeding

EXPOSURE TO EXTREME TEMPERATURES AT THE POST-LARVAL STAGE CAUSES MASCULINIZATION OF GUPPY (Poecillia reticulata)

Andita Rahelia¹, Ignatius Hardaningsih¹, and Dini Wahyu Kartika Sari^1,*

¹Genetics and Fish Breeding Laboratory, Fisheries Department, Universitas Gadjah Mada, Gd. A4 Bulaksumur, Yogyakarta, Indonesia

^*Corresponding author: dini.sari@ugm.ac.id

Global warming can pose a real threat to the sustainability of aquatic organisms, including fish. Our previous research reported that extreme temperature treatment on the 2 days after birth guppy larvae causes feminization. This study aimed to determine the effect of extreme-temperature exposure on guppy post-larvae at a certain period. Guppy larvae at 5 days after birth (DAB) and 6 DAB) were treated with extreme temperature at 36 °C for one day, followed by two-month monitoring for sex determination. The parameters observed were guppy morphology, male or female of guppy genotype, and gonadal histology. Each treatment consisted of 3 replicates. Data of sex determination were analyzed using paired simple t-test. The results showed that treatment on 5 DAB guppy fish larvae was dominated by males. Of the relative morphologically male, there were 60% genotypically female. Of these masculine guppies, 33,3 % of testes have developed and 66,7 % have undeveloped. Based on all parameters observed, it can be concluded that exposure to high temperatures in 5 DAB guppy post-larvae causes masculinization.

Keywords: gonad, guppy, masculinization, temperature

FIRST BREEDING PROGRAM OF THE PORTUGUESE OYSTER Ccrassostrea angulata DEMONSTRATED SIGNIFICANT SELECTION RESPONSE IN TRAITS OF ECONOMIC IMPORTANCE

Sang V. Vu^ab, Wayne  Knibb^a,  In V.Vu^b, Wayne O'Connor^ac,  Michael Dove^c,  Nguyen Hong Nguyen^a

a GeneCology Research Centre, School of Science and Engineering, University of the Sunshine Coast, Maroochydore, QLD, 4558, Australia

b Researcher Institute for Aquaculture number 1, Tu Son, Bac Ninh, Vietnam

c Industry and Investment NSW, Department of Primary Industry, Port Stephens Fisheries Institute, Taylors Beach, NSW, Australia

Corresponding author: vvsang@ria1.org

The Portuguese oyster Crassostrea angulata is one of the economically important  mollusc species but to date there has been no genetic improvement program conducted for this species. The principal aim of this study was to assess genetic gains achieved from a selection program for improved whole weight at harvest over three generations from 2015 to 2017. A total of 30,212 oysters had performance data recorded; they were the offspring of 323 sires and 461 dams. Linear mixed models were used to estimate genetic parameters of the traits studied. Selection for improved harvest whole weight achieved significant direct response by 17.4% after three generations. There were also positively correlated changes in soft tissue weight and shell shape traits (3.67% and 3.98%, respectively). The genetic gains in harvest whole weight and favourably correlated changes in meat yield and shell shape traits were consistent with the positive genetic correlations of whole weight with these  traits  (0.08–0.50). There is abundant genetic variation in the selection criterion (heritability for whole weight = 0.24), suggesting that the present population of Portuguese oysters will continue showing responses to future selection. The estimates of heritability for meat yield and shell shape traits were low (0.10–0.16). Hence, a multi-trait selection program can  be  used  to  enhance  overall  productivity  and  economic   return  for  oyster  producers.

Keywords: portuguese oyster, generation, selection criterion, heritability

LENGTH-WEIGHT RELATIONSHIPS AND REPRODUCTIVE ASPECTS OF GOLDENSNAPPER, Lutjanus johnii  IN TERENGGANU WATERS, MALAYSIA

Rahman, Md. M, Md^12,, Ariffin, N. Asma^1*, Giat, S. Ying¹, Bakar,A. Abu³, Jaafar, T. N. A. Mat¹,Min, P. Tan⁴, Nor, S. A. Mohd⁴, Ghaffar, M. Abd.⁵, Arai, Takaomi⁶, Habib, Ahasan^1*

¹Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, Terengganu, Malaysia

²Faculty of Fisheries, Sylhet Agricultural University, Sylhet, Bangladesh

³Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris (UPSI), Tanjong Malim, Perak, Malaysia

⁴Institute Marine Biotechnology (IMB), Universiti Malaysia Terengganu, Terengganu, Malaysia

⁵Institute of Tropical Aquaculture and Fisheries (AKUATROP), Universiti Malaysia Terengganu, Malaysia.

⁶Environmental and Life Sciences Programme, Faculty of Science, Universiti Brunei Darussalam,Jalan Tungku Link, Gadong BE1410, Brunei Darussalam

*Corresponding author: a.habib@umt.edu.my, nurasma@umt.edu.my

The present study reports on the length-weight relationships (LWRs) and reproductive aspects of the commercially and economically important snapper species Lutjanus johnii collected from Pulau Kambing fish landing port, Terengganu, Malaysia. Samples were collected monthly from March 2022 to September 2022. A total of 75 fish specimens were morphologically identified based on Allen, 1985. Subsequently, these specimens were measured and resulted in total length ranging from 41.7 cm to 74.7 cm (mean  ±  SD: 57.19 ± 7.72 cm) and body weight 1015.2 g to 4860.1g (mean  ±  SD: 2571.17 ± 906.34 g). In LWRs the allometric coefficient b value was 2.623 (negative allometric) and the value of determination coefficients r² was 0.948. Sex ratio, gonadosomatic and hepatosomatic index, spawning period, fecundity, condition factor K, and the gonadal maturation stage were assessed for reproductive biology study. Males were significantly overrepresented in the sex ratio of 1.08: 1 (Male: Female). The condition factor K peaked in March (1.459195), while its lowest was in June (1.214802). The monthly deviation of the gonadosomatic index (GSI) was highest in April and then gradually declined in the following months. The assessment of the relationship between the condition factor (K) and the hepatosomatic index revealed that body energy mobilization aids in gonad development. The fecundity of 17 mature females ranged from 49.4 cm to 74.7 cm, with body masses ranging from 2598.9 g to 4860.1 g, yielding 1, 52,161 to 9, 60,888 ova. Five gonad stages were determined based on the ovary's maturity. As of now, the results of this study offer vital information about LWRs and reproductive characteristics of L. johnii, which will serve as a baseline for future fishery management in this region.

Keywords: Golden snapper, Lutjanus johnii, reproductive biology, South China Sea, Malaysia

PROPAGATion of ReD SEA GRAPE, Botryocladia sp. (Rhodophyta, TISSUE CULture) by tissue culture

Penpitcha Kimtin¹, Rapeeporn Ruangchuay¹*, Patchara Maeroh²

¹Department of Agricultural and Fishery Science, Faculty of Science and Technology, Prince of Songkla University, Pattani 94000, Thailand.

² Satun Marine Fisheries Research and Development Center, Department of Fisheries, Satun 91110 Thailand

^*Corresponding author: rapeeporn.r@psu.ac.th  

The study on tissue culture of red sea grape Botryocladia sp. from tissue was done to propagate the ornamental alga to support the ornamental plant marketing. Three centimeter in length of the algal tissue was cut with fork-branch and without fork-branch. The tissue was placed on substratum individually and put to culture in the 1-t cement tank for 6 weeks in hatchery. The culture condition was set at 35 ppt, nitrate-nitrogen 0.04 mg·L^-1, light intensity 400-550 µmol photon m^-2s^-1 and enriched with modified Guillard’s medium and an aeration. The weight, length, and size of water sac of the alga were measured, in addition, water sac and new branch were counted in every two weeks. The result showed that the weight of tissue with water sac was gained higher than that of tissue without water sac with of 131.9 % within 6 weeks. The tall of plant in final week showed 7.3 ±1.2 and 6.7±1.1 cm from tissue with branch and without branch, respectively. Number of the new branches was observed in tissue with fork-branch higher than that in tissue without fork-branch while sac size from tissue without fork-branch showed bigger than that in tissue with fork-branch. An appropriate propagation of red sea grape Botryocladia sp. should use the tissue with fork-branch.

Keywords: Botryocladia, red sea grape, tissue culture, ornamental plant