WIDTH-WEIGHT RELATIONSHIP ANALYSIS OF BLUE SWIMMING CRAB INSTAR (Portunus pelagicus Linnaeus, 1758) IN BANTAYAN ISLAND, CEBU, PHILIPPINES

 Brandon Briggs Cobacha Silvano1*, Quenstein D. Lauzon2   and Lebeth C. Manguilimotan3

^1,2Visayas State University Tolosa, Tanghas, Tolosa, Leyte Philippines;

³Philippine Association of Crab Processors Inc. Cebu City

The analysis of the width-weight relationship for Portunus pelagicus instar in the coastal area of Luyong Baybay and Guiwanon, Bantayan Island, Cebu was carried out from August to October 2021. A total of 632 blue swimming crab instars were randomly collected from the two sampling stations from August to October 2021. Of the total number of instars sampled, 369 were male while 263 were female. In Luyong Baybay, 137 instars were collected while 495 were recorded in Guiwanon. In terms of their carapace width, instars sampled from Luyong Baybay had a range of 2.3 to 10.33 mm while 0.9 to 9.5 mm was recorded in Guiwanon. A weight range of 1 to 75 grams was observed from the sampling stations of Luyong Baybay while 0.03 to 65.25 g in Guiwanon. The coefficient correlation for P. pelagicus instar in Luyong Baybay showed a strong positive relationship (0.81) indicating that as the width of the crab instars increases, the weight also increases. However, a less strong coefficient correlation (0.60) was observed in the width-weight relationship of instars collected from Guiwanon. The values of both condition indices dictate that P. pelagic instar is doing better in Luyong Baybay than in Guiwanon. Factors such as impacts of sustainable ecosystem management measures, ecological conditions, fishing pressure, and environmental parameters which include salinity, temperature, and food availability were linked to the observed width-weight variations of the instar sampled.

Keywords: Portunus pelagicus, instar, width-weight relationship

LITTER DECAY AND NUTRIENT DISCHARGE IN MANGROVES, WITH SIGNIFICANT ASSISTANCES OF MICROBES AND DETRITIVORES ON ECOSYSTEM FUNCTIONS

 Mohammad Ahsanul Islam^1,2, Abu Hena Mustafa Kamal^1*, Mohd Hanafi Idris¹, Wan Mohd Rauhan Wan Hussin¹, Md Khurshid Alam Bhuiyan³, Muhammad Shareifuddin Mohd Sukeri¹, Md Masum Billah⁴

¹Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu. Kuala Nerus, 21030 Terengganu, Malaysia

²Department of Oceanography, Shahjalal University of Science and Technology

Sylhet 3114, Bangladesh

³Department of Physical Chemistry, Faculty of Marine and Environmental Science, University of Cadiz, Poligono Rio San Pedro s/n, 11510, Puerto Real, Spain

⁴Inter-Departmental Research Centre for Environmental Science-CIRSA, University of Bologna, Ravenna Campus, Via S. Alberto 163, 48123 Ravenna, Italy

*Corresponding author: a.hena@umt.edu.my

Mangroves are well known for their high primary productivity and potentials for “blue carbon” sinks in the tropical and sub-tropical estuarine and coastal ecosystems. Litter decomposition plays significant role in carbon dynamics and energy flows in mangroves, which is regulated by two important factors i.e., interspecific variations in litter quality and soil organisms (microbial decomposers and detritivores fauna) in the mangrove ecosystems. Litter decomposition rates may also be affected by mesh bags used to exclude soil fauna. However, the lack of data on this issue, hindering our understanding of the faunal impact on ecosystem functioning. Thus, we investigated: i) what is the rate of differences in decomposition pattern and nutrient release between litter from two mangrove species and ii) effects of the mesh bags on litter decomposition and consequent nutrient releases. A 120 days study trial was conducted in a tropical lagoon mangrove ecosystem to investigate the effects of enclosing in two mesh sizes i.e. 0.20 mm, 0.50 mm and unprotected (natural) leaf litter of two mangrove species namely Bruguiera gymnorrhiza and Rhizophora mucronata. During decomposition the unprotected leaf litter significantly lost the weight compared to other treatments. Overall, the percentage of wet loss and decay rate were high during the first 30 days of the experiment. Moreover, the decay pattern data between the two species indicated significant high decay rates of B.  gymnorrhiza compared to R. mucronata. In both species, significant nutrient (C and N) release was observed relative to the decomposition time. We concluded that, using different mesh bags in decomposition experiment can improve our understanding of the mangrove faunal impacts on the ecosystem functioning and dynamics in lagoon ecosystems. 

Keywords: Ecosystem services, Plant soil interaction, Carbon dynamics, Organic matter decomposition, Energy flow

REPRODUCTIVE ASPECT OF THE COASTAL TREVALLY Turrum coeruleopinnatum FROM TERENGGANU WATERS, SOUTH CHINA SEA, MALAYSIA.

 Muhammad Hanif Fadzli*¹, Tun Nurul Aimi Mat Jaafar¹, Nuralif Fakhrullah Mohd Nur¹, Mohd Sharol Ali¹, Min Pau Ta ², Rumeaida Mat Piah¹

¹Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia.

² Institute of Marine Biotechnology, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia.

^*Corresponding author: hanif9611@gmail.com 

 Coastal trevally, Turrum coeruleopinnatum (Ruppel, 1830) is a species live inshore marine and belongs to Carangidae family. This species is one of species that important in commercial value. However, the understanding of its biology is poorly studied. Thus, this study described the reproductive biology of T. coeruleopinnatum captured in Terengganu waters, Malaysia. Fish samples were collected monthly from Pulau Kambing fish landing port, Terengganu, Malaysia from April 2019 to March 2020. A total of 687 individuals were observed, with 362 males (52.69%) ranging in length from 6.3 cm to 26.6 cm (mean ± SD : 13.2 ± 3.84) and 325 females (47.31%) ranging in length from 9.0 cm to 26.4 cm (13.9 ± 3.34). The sex ratio shifted dramatically in favour of males (1 : 0.90) (x² : 1.99). Monthly variation of gonadosomatic index (I_G) peaked for males and females between February and April, indicating the spawning season. The relationship between the condition factor (K) and hepasomatic index (I_H) revealed that the mobilization of energy from body assist in gonad maturation. The fecundity analysis ranged from 15.7 cm to 21.4 cm, with body mass of 142.6 g to 333.0 g, yielding 20, 438 to 121, 829 eggs. Males reaching maturity earlier than female at 15.78 cm compared to 12.45 cm for females. This research contributes to a better understanding of the reproductive characteristics of T. coeruleopinnatum, which aid in future establishment of rules and regulations for effective fishery management in Terengganu waters in the future.

Keywords: Turrum coeruleopinnatum, Fecundity, Length at first maturity (Lm), Reproduction, Sex ratio, Spawning period

SOME ASPECTS ON REPRODUCTIVE BIOLOGY OF FEMALE MUD CRAB, SCYLLA OLIVACEA, FROM TWO DIFFERENT LOCALITIES IN THE SOUTHERN REGION OF THAILAND

 Husneya Rensep^1* Sukree Hajisamae¹, Yutaka Takeuchi², Sofiyudin Maae³ , Sitthisak Jantarat⁴, Supaporn Saengkaew⁴,

¹Department of Technology and Industry, Faculty of Science and Technology, Prince of Songkla University 94000, Pattani, Thailand

²Faculty of Biological Science and Technology, Kanazawa University 927-0552, Ishikawa, Japan

³Faculty of Natural Resources Prince of Songkla University, 90110 Songkhla, Thailand

⁴Biology Program, Department of Science, Faculty of Science and Technology, Prince of Songkla University 94000, Pattani, Thailand

^*Corresponding author: husneya.h@outlook.com

Mud crab (Scylla spp.) is an important species and highly valued as a source of food around the world, especially in tropical and subtropical countries. This study aims to compare body size, length–weight relationship and size at first maturity of female orange mud crab (Scylla olivacea) from two different localities in Thailand (Pattani province in the South China Sea and Ranong province in the Andaman Sea). Crab samples were collected from the fishermen from both regions between May 2020 to July 2020 and brought back to the laboratory for further analysis. They were preserved, measured for size and weighted prior to an application of reproductive biology study. Ovary weight was measured, fecundity was assessed and GSI was calculated for crab at stage 4 for both localities. It was found that the larger size, ovary weight, GSI value and fecundity of crab were found in Pattani province compared to Ranong province. The fecundity of crab from Pattani and Ranong were 1.56±0.34 and 0.92±0.31 million. Size at first maturity of mud crab from Ranong and Pattani were 96.52 mm. and 103.37 mm, respectively. There were positive relationships between internal carapace width (ICW), carapace length (CL), abdomen width (AW), and body weight (BW) with ovary weight (OW). However, the negative relationship between internal carapace width (ICW), carapace length (CL), abdomen width (AW), and body weight (BW) with %GSI were significantly found. This scientific data is able to serve as a basic information for the proper management of crab resources of these two different regions of Thailand.

Keywords: Reproductive biology, mud crab., Scylla olivacea., size spectra, size at 50% maturity, fecundity

MOLECULAR IDENTIFICATION OF KAPPAPHYCUS SPECIES COLLECTED IN ILOILO AND ROMBLON

John Rey T. Rasgo¹, Jonalyn P. Mateo^1,2*, Rema C. Sibonga^2,3, Victor Marco Emmanuel N. Feriols², Anicia Q. Hurtado², Maria Rovilla J. Luhan²

¹Institute of Marine Fisheries and Oceanology, University of the Philippines Visayas Miagao, Philippines 5023

²Institute of Aquaculture, University of the Philippines Visayas Miagao, Philippines 5023

³Center for Chemical Biology and Biotechnology, University of San Agustin, Iloilo City, 5000, Philippines

*Corresponding author: jpmateo@up.edu.ph

For more than 50 years, Kappaphycus, specifically K. alvarezii and K. striatus, have been cultured in the Philippines. Both species showed different varieties and color morphotypes which led to confusion, difficulties in species identification and eventually resulted to misidentification owing to its morphologically diverse nature, lack of clear diagnostic on morphological characteristics and inconsistent use of local and commercial names. The use of molecular markers has been proven to be effective in delineating Kappaphycus species from each other. In this study, cultivated seaweeds from Iloilo and Romblon were collected, morphologically described and analyzed for molecular identifiction. Genomic DNA was extracted using a modified CTAB protocol and amplified by polymerase chain reaction (PCR) using COI-5P and cox 2-3 spacer as molecular markers. The PCR products were purified and sent to Philippine Genome Center Visayas for sequencing. Based on external morphology, specimen from Iloilo and Romblon were initially identified as K. alvarezii (tambalang variety) and K. striatus (kulot variety), respectively. The species-level affiliation of the generated sequences was initially determined using BLAST analysis and confirmed by phylogenetic analysis. Both Iloilo and Romblon specimens were K. alvaezii based on BLAST results. The maximum likelihood tree revealed that the two specimens are of the same clade with other K. alvarezii specimens. In summary, kulot and tambalang, though morphologically different are both K. alvarezii. Thus, molecular technique is an important tool in proper identification of the cultivated seaweed.

Keywords: Color morphotypes, Kappaphcyus, Phylogenetic analysis