NEWS
First known warm-blooded fish!!
What's the difference between a fish and a bird? As science reveals newer and stranger creatures, few hardline rules about classification remain. And one fish just knocked another rule off the table.
The opah is a large, deep-sea fish, commonly found off the coast of Hawaii and west Africa. It’s also the first and only fish known to be warm-blooded, or endothermic. A new study by NOAA Fisheries describes how the opah generates full-body heat by vigorously flapping its pectoral fins, and retains that warmth with a radiator-like system of arteries. Findings were published Thursday in Science.
Opah, or Lampris guttatus, can grow to be nearly 7 feet in length. The species belongs to the order Lampriformes, which is also home to various species of oarfish. Most lampriformes are slow-moving ambush predators, as they tend to live at frigid depths where intense physical activity is too energy-expensive. But powerful, horizontally positioned pectoral fins suggest that opah are capable of rapid movement.
Information from University
Not vailable
NEW PUBLICATION
Artificial breeding and larval rearing techniques to conserve ayu, Plecoglossus altivelis (Plecoglossidae)
By Linh Manh Ha & Kei'ichiro Iguchi
Ex-situ conservation, which is important to protect critically endangered species, requires special artificial breeding and rearing techniques during the early life stages of a species. This study describes the artificial breeding and larval rearing techniques to conserve ayu (Plecoglossus altivelis), an important fish that is endangered in some locations. Fish eggs and milt were acquired from mature fish by gently pressing the fish abdomen; subsequently, artificial insemination was performed by gentle mixing. The fertilized eggs were then incubated in running freshwater (for approximately 14 days). After hatching, the larvae were placed in brackish water (ca. 10‰ salinity; 7-8 mg L-1 dissolved oxygen) to maintain live food to the larvae. From the 1st to 35th day after hatching (DAH), the larvae were fed with live rotifers. Subsequently, from the 15th DAH onwards, the larvae were fed with brine shrimp nauplii along with rotifers and were familiarized with artificial food. After the fish gained a body length of 4-5 cm and started consuming 0.5-0.8 mm formulated food grain, they were transferred to a fingerling nursery with freshwater for further cultivation. This study also noticed that the susceptible stages of ayu larvae were at approximately 14-16th and 40-45th DAH. This work provides necessary information to design a conservation plan for the ayu population in the southern distribution range of this species where it is currently facing threats of extinction, such as in Vietnam. Additionally, the study describes the rotifer culturing technique that can assist in conducting larviculture.
If you have interest with this paper, you can read it freely at This NEW PAPER
A three pelvic fins fish: a very rare mutation
By Linh Manh Ha & Kei'ichiro Iguchi
Our newly published study describes a fish individual of Plecoglossus altivelis ryukyuensis with three pelvic fins collected from a hatchery-reared population in Amami-oshima Island, Japan. The additional pelvic fin had the same number of rays as the neighboring pelvic fins (eight fin rays), and its girdle was fused with that of the neighbor. The comparison of morphometric measurements and meristic counts of the abnormal specimen with those of the normal specimens revealed that this abnormality was not a syndrome when all other characteristics were in the expected ranges. The condition factor of abnormal fish was close to the ideal value, suggesting that this abnormality did not severely affect the activities of the fish under rearing conditions. Well-managed rearing conditions might contribute significantly to the survival and growth of abnormal fish. The cause of this abnormality is unclear, but the limited diversity in the genome of the subspecies is assumed to be a probable factor.
If you have interest with this paper, you can read it freely at This Link.
