Anthropogenic emission of CO2 into the atmosphere has been increasing exponentially, causing ocean acidification (OA) and ocean warming (OW). The “business-as-usual” scenario predicts that the atmospheric concentration of CO2 may exceed 1,000 µatm and seawater temperature may increase by up to 3 °C by the end of the 21st century. Increases in OA and OW may negatively affect the growth and survival of reef corals. In the present study, we separately examined the effects of OW and OA on the corals Acropora digitifera and Montipora digitata, which are dominant coral species occurring along the Ryukyu Archipelago, Japan, at three temperatures (28 °C, 30 °C, and 32 °C) and following four pCO2 treatments (400, 600, 800, and 1,000 µatm) in aquarium experiments. In the OW experiment, the calcification rate (p = 0.02), endosymbiont density, and maximum photosynthetic efficiency (Fv/Fm) (both p < 0.0001) decreased significantly at the highest temperature (32 °C) compared to those at the lower temperatures (28 °C and 30 °C) in both species. In the OA experiment, the calcification rate decreased significantly as pCO2 increased (p < 0.0001), whereas endosymbiont density, chlorophyll content, and Fv/Fm were not affected. The calcification rate of A. digitifera showed greater decreases from 30 °C to 32 °C than that of M. digitata. The calcification of the two species responded differently to OW and OA. These results suggest that A. digitifera is more sensitive to OW than M. digitata, whereas M. digitata is more sensitive to OA. Thus, differences in the sensitivity of the two coral species to OW and OA might be attributed to differences in the endosymbiont species and high calcification rates, respectively.

Ikan petek merupakan salah satu ikan ekonomis penting di Indonesia. Penelitian ini bertujuan untuk mengetahui pertumbuhan  ikan  petek  (Leiognathus    equulus) di Perairan Kabupaten Tegal. Penelitian dilaksanakan di Perairan Larangan dan Suradadi, Kabupaten Tegal. Penelitian ini menggunakan metode deskriptif. Analisis data pertumbuhan dilakukan dengan menggunakan persamaan Von Bertalanffy. Panjang ikan petek di Perairan Larangan berkisar antara 1,6 – 6,9 cm dan Perairan Suradadi berkisar antara 1,6–9,4 cm. Pertumbuhan ikan petek di Perairan Larangan diperkirakan mampu mencapai panjang maksimal (L∞) sebesar 7,26 cm, sedangkan di perairan Suradadi sebesar 9,89 cm.Kata Kunci: Ikan  petek  (L. equulus), Pertumbuhan, Ekosistem Mangrove, Kabupaten Tegal