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Pre-spawning reproductive behavior on the mudflat surface was reported previously for the mudskipper, Periophthalmus modestus, but it remains unknown how a pair spawns and fertilizes eggs within the spawning chamber of a burrow. In this study, we recorded reproductive behaviors from burrow entry of a pair to the departure of a female. In those cases, where spawning was suspected from a drastic reduction in the distension of the female’s belly (N = 4), the female remained inside a burrow for 240-350 min without coming out onto the mudflat surface. In contrast, the male often but irregularly emerged from the burrow. In one case, a second male entered a burrow 169 min after the burrow entry of a female, resulting in her desertion from the burrow without spawning. During burrow cohabitation of the pair, burrow openings were often clogged by mud from inside. After the female left the burrow, the male remained inside the burrow for variable periods. Then, the male guarded the burrow for about one week. Upon termination of the burrow guarding, the male began excavating a new burrow near the previous one or repaired the burrow that he had guarded. A hypothesized scenario is proposed for the reproduction of this species for further investigation., International Journal of Aquatic Biology, 8(6), pp. 412-420; 2020

The honeycomb grouper, which is a lunar-synchronized spawner, is an important fishery target species in Okinawa. In this study, to clarify the spawning characteristics of this species, we observed mass spawning (4 or 6 males and 20 or 22 females in 3-t tank) and single-pair spawning (one male and one female in a 200 l tank) using rearing experiments. The mass spawning results indicated spawning started 3 days after the full moon and continued for several days. However, the single-pair spawning results showed the starting date of spawning varied between individuals. The spawned eggs in 1 female were confirmed for 4 consecutive days (20,000–70,000 per day). The egg buoyancy, fertilization, and hatching rates were high in single-pair spawning until day 3. However, the number of spawned eggs, buoyancy, fertilization, and hatching rates at day 4 were extremely low, suggesting that actual spawning occurred for 3 days. 沖縄地方では重要な漁業対象種とされているカンモンハタの産卵特性を，雄4と雌20尾または雄6尾と雌22尾による飼育による集団産卵と雌雄1尾ずつ飼育によるペア産卵によって調べた。集団産卵では，満月の3日後あるいは4日後より数日間にわたって産卵が確認された。しかしペア産卵の結果，産卵の開始日は個体によって異なっている（満月の3日後から6日後）ことがわかった。ペア産卵群では4日間連続して放卵された卵が確認された。1尾の雌の産卵量は，1日あたり2,000粒から7,000粒であったが，4日目には急減した。浮上卵率，受精率，孵化率は産卵開始から3日目までは高かったが，4日目のそれらは極めて低かった。以上の結果より，本種の産卵は満月の3日目より開始され，1尾の雌が4日間連続で産卵するが，実質的な産卵は3日間であることがわかった。, Aquaculture Science, 68(3), pp. 235-242; 2020

Additional file 1: Supplementary Fig. 1. Structure of non-steroidal anti-inflammatory drugs. (A) Structure of salicin-related compounds. Salicin is a water-soluble β-glucoside and is produced in willow bark. Salicin is metabolized into salicylic acid, an active form of the willow bark decoction or extract. Acetylsalicylic acid is known as Aspirin and is one of the most widely used medications for pain, fever, and inflammation. (B) Representative non-steroidal anti-inflammatory drugs. Non-steroidal anti-inflammatory drugs (NSAIDs) developed in the 1960s inhibit both cyclooxygenase-1 (COX-1) and COX-2 and decrease inflammation. Supplementary Fig. 2. Structure of COX-2 inhibitors. COX-2 selective inhibitors are non-steroidal anti-inflammatory drugs (NSAIDs) that decrease inflammation and have reduced risk of adverse gastrointestinal effects. Supplementary Fig. 3. Structure of glucocorticoids. Glucocorticoids are a class of corticosteroids that bind to the glucocorticoid receptor involved in the regulation of glucose metabolism. Glucocorticoids suppress the immune system and reduce inflammation. Supplementary Fig. 4. Structure of representative disease-modifying anti-rheumatic drugs. Disease-modifying anti-rheumatic drugs (DMARDs) comprise a group of compounds that alleviate rheumatoid arthritis by slowing down the progression of the disease.