Here, we report the first record of the invasive mussel species Mytella strigata Hanley, 1843 in Panguil Bay, southern Philippines confirmed through its conchological features. Mussels appeared in dense mats attached to rocks, wood, and substrate in the intertidal region in the innermost portion of the bay. Locals first noticed the species in late 2018, which, according to them, adversely affected their catches of mangrove crabs Scylla spp. and the Asian hard clam Meretrix meretrix Linnaeus, 1758. There is a need to ascertain the distribution of the species within the bay, investigate socio-ecological and economic impacts, and formulate monitoring, surveillance, and impact mitigation measures.
The significant exploitation of the high-value white teatfish, Holothuria fuscogilva, has raised global concerns about the species' wild populations. Aquaculture technology development may potentially restore dwindling stocks; however, it remains to be established in the Philippines. This study reported the first successful mass production of H. fuscogilva in the Philippines. The broodstock was collected on two occasions from Tubajon, Laguindingan, Misamis Oriental (May and June 2020). All broodstock survived with no evisceration in 30 min (27.8–35.2 ̊C) of transport to the hatchery. Broodstock was induced to spawn using spawning techniques adopted from those of Agudo (2006) with modification in three events (July, August, and December 2020). However, successful spawning only occurred when the temperature was reduced by 7 ̊C (extreme cold shock).H. fuscogilva produced 3.4 million eggs in three spawning inductions at > 88% fertilization rate. The eggs hatched 2–3 d post-fertilization. Generally, the embryonic development of H. fuscogilva was radial holoblastic, and the larval development had the same pattern as other sea cucumber species. The auricularia stage was observed at Days 4–27, followed by the doliolaria stage at Days 28–32, and pentactula stage at 33–39 d post-fertilization. An average of 1.1% of the fertilized eggs proceeded to the juvenile stage at 40–45 d post-fertilization. Over 4 mo, juveniles grew at 0.03 ± 0.002 g d–1. This is the first documentation of the larval development of H. fuscogilva and the first production of the juvenile stage in the Philippines, where 15,000 juveniles are being grown in the hatchery for future broodstock.
The relationship between length and weight is non-linear. Predictive modelling using linear regression methods subjects these variables to transformation which results in models of poor predictive value. Hence, a comparative study on developing a predictive model using traditional (length-weight relationship, LWR; multiple linear regression, MLR) and artificial intelligent (artificial neural networks, ANN) methods was conducted. Specimens (n = 320) of the horse mussel Modiolus modulaides were randomly collected from October 2018 to March 2019 at the coastal area of Dumangas, Iloilo, Philippines. Shell length, shell width and shell height were used as predictor variables for total weight. A multi-layer perceptron architecture model was used and the values were determined by the ANNs model using the actual data. In addition, LWR and MLR models were generated from the same data after log-transformation. The results indicated superiority of the ANN model to predict mussel weight to traditional LWR and MLR models. The ANNs model had the highest correlation coefficient and lowest errors among the predictive models. The ANNs model generated from this study can be a good alternative to existing models and may be useful in sustainable fisheries management.
A preliminary investigation on the size-specific variation in the length-weight relationship, relative condition factor, and gonad maturation of Bigeye scad, Selar crumenopthalmus, was conducted from April to May 2018 in the northern Sulu Sea, Philippines. A total of 435 samples were collected using a ring net. The results showed a shift from isometric to negative allometric growth pattern, good condition, and earlier maturation in males in S. crumenopthalmus. These findings help us understand some aspects of the S. crumenopthalmus population in the area; however, further research needs to be conducted with increased sampling duration and frequency.
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