by AquaNerd | Apr 29, 2014 | DIY, Industry, Opinion, Tanks
Phosphate levels have long been the debate of reef keeping aquarists, with folks generally falling into one of two categories. Most hobbyist have the persisting opinion that elevated phosphate concentrations are generally bad because they fuel algae growth and prevent coral calcification. The other group takes almost an entirely opposite approach. They actually welcome slightly elevated phosphates because of a plethora of reasons, including the desire to avoid chasing numbers, to avoid using certain types of artificial controls, or simply because their phosphate levels have had a beneficial impact on their coral growth and haven’t led to other issues. Regardless of which side of that aisle you fall on, there is a big underlying problem with determining the amount of phosphate in your aquarium water…it just cannot be done accurately by the tools readily available to the aquarium trade. Phosphate checking in the aquarium hobby is tackled with two different methods. The longest standing method is based on titrating a water sample with a couple of chemicals and comparing the color change to a scale of phosphate concentrations. This method is quick and easy to use, but it doesn’t offer the resolution that aquarists often need. Most of the time, if the phosphate isn’t really high, it shows as zero on the scale and aquarium keepers are lulled into a false sense that their water is phosphate-free by AquaNerd | Apr 25, 2014 | Conservation, Invertebrates, Reef
Image Credit: Getty Images The crown-of-thorns starfish has been one of the single most destructive threats facing Australia’s Great Barrier Reef. Its voracious appetite for hard coral flesh combined with its accelerated life cycle have caused massive losses to the tune of nearly 50% of all corals along a 1,500-mile stretch of the Queensland coast over a few decades. This has caused some drastic measures to be taken by wildlife officials, most of which has been centered around an ineffective 20-point injection method that kills the starfish. According to multiple news stories, however, that method was replaced with a much more effective single-injection method that has led to more than 250,000 starfish deaths over the last two years alone. The new injection method is also more effective in that it kills the starfish in just two days and is supposedly harmless to other marine life. Previous methods consisted of injecting acid into each of the starfish’s arms, which could obviously do some pretty significant damage to nearby corals as well. According to the Daily Mail’s coverage of several interviews with Australian officials, the Australian government has already provided £560,000 of funding towards removing the starfish, with another £1.1million in the budget for future starfish destruction. by AquaNerd | Apr 23, 2014 | Conservation, Eye Candy, Invertebrates, Photography
Daniel Stoupin is determined to win the internet. He has already shown us how corals can make for some terrific subjects of time lapse photography, and his latest video shows how freshwater life can be just as interesting when displayed in a similar high def format. The clip shows an amazing world full of life, some of which looks like it would be right at home in the oceans or in our aquariums. It focuses on bryozoans, water fleas, mayfly nymphs, mosquito larvae, water mites, ostracods, and the amoeba…which looks extremely menacing in this video. To view this tiny pond life, Daniel used microscopy techniques and macro photography. Unlike the coral video, which used hundreds of thousands of still images to create a breathtaking time lapse, this video was made from a week’s worth of videography coupled with years of experience in finding and videoing these interesting critters. We don’t need to dive into the deep ocean to find the most unusual lifeforms. This short clip is a journey into a bizarre world of microscopic inhabitants of pond water. You will see water fleas, bryozoans, water mites, mayfly nymphs, ostracods, and, of course, hydras by Admin | Apr 15, 2014 | Conservation, Fish, Science
3 day old P. venusta larvae. Photo credit: Karen Brittian. Larval rearing trials began with the spawning of a Paracentropyge venusta pair in the summer of 2013. The first successful larval rearing trial started with a small spawn on November 13, 2013. This was the fifth larval run with this species and the focus was on food density and consumption at different developmental phases. The diet consisted of both cultured copepods and wild collected plankton with all food items being less than 100 microns in size. To assess consumption rates, five random samples were taken for initial food counts at the start of each test period. All food items added to the larval tank during the test period were counted while maintaining a density of 1 to 2 food items per ml in the water column. At the end of the time period counts were again done to determine larval consumption. At this point a 75% water change was carried out. I was surprised at the amount of food these little larvae could put away and as an example, at day 28 post hatch the larvae consumed approximately 2,150 food items each over a 12 hour period, (5:00am to 5:00pm). 32 day old P. venusta larvae. Photo credit: Leighton Lum. At one month of age the larvae started targeting larger prey items and ignored the food items less than 100 microns in size. At this point newly hatched and enriched Artemia were added to the diet along with adult cultured copepods. The larvae also began to display benthic behavior by associating with the corners of the tank, the air stone and airline tubing. A piece of dried coral rubble was added where the larvae took shelter. The larvae continued to grow and develop; they were moved into a growout tank at 57 days old. At this point we had 17 larvae remaining which equates to 6% survival from hatch. The development of juvenile colors came slowly. On day 95 they had black pigment on parts of their fins and tail. A month later at 130 days old they were the beautiful blue and yellow of the adults. 115 day old P. venusta juvenile. Photo credit: Leighton Lum. Larval rearing of this species proved relatively “easy” in their first few weeks of the larval stage after which point larval development and growth seemed to slow. This could be attributed to the type and amount of wild plankton collected and fed out at that time. I feel that the larval phase could be shortened and improved upon in the area of diet. After metamorphosis the larvae were again slow to develop with a reluctance to accept non-living food items and this is also another area for improvement. The Reef Frenzy and Herbivore Frenzy frozen foods were the first choice of the juveniles when they began to accept non-living food. Currently these juveniles are fairly bold and are consuming frozen and dry foods with gusto. by Admin | Mar 25, 2014 | Conservation, Fish, Science, Tanks
Day 60 yellow tang larvae. Photo credit: Dean Kline.Since we last wrote at Day 50, we’ve observed a lot of interesting things with our yellow tang larvae. Probably the most important thing we observed is their very inefficient feeding capability. At their size (~1cm), newly hatched Artemia nauplii should have been easy prey, but time and time again we’d watch them strike and miss, or partially catch one only to spit it out. Artemia nauplii definitely don’t seem to be adequate to sustain yellow tang at this stage in development. Likewise enriched Artemia were all but rejected. Also, at this stage, the fish seem to rely on their large pectoral fins for propulsion and were very awkward moving around the tank. We would frequently observe them floundering about and then suddenly right themselves and swim on quite normally. This seemed to require a lot of energy, which in their compromised nutritional state, likely lead to some additional stress. They also tended to gravitate to the tank walls, and appeared to sometimes be grazing or picking things from the walls. Although we included live rock, macroalgae and other substrate in the tanks at this point, we did not observe any sign of the fish wanting to be near the bottom. Settlement seemed to be a long way off. Day 83 yellow tang larvae (Lucky). Photo credit: Chad Callan. From Day 50-60 we continued to lose fish daily; which seemed to be stuck in metamorphosis and were not advancing through this particular stage. We quickly realized that yellow tangs probably have some rather specific nutritional and/or environmental requirements that we were not meeting. We had only ~25 fish at day 60 and were down to 3 fish by Day 65. It seemed we were at the end of this run. However, some hope remained as our sole surviving fish, “Lucky”, refused to succumb to the fate of his tank-mates. We were surprised daily to see him swimming each morning from Day 67 onward. He seemed to be growing and his dorsal spine was definitely shrinking (a sign that this stage might be ending). Unfortunately, this “lucky streak” ended on Day 83. From the pictures you can certainly see that “Lucky’s” body was beginning to complete this stage of metamorphosis, with his dorsal spine nearly gone and head shape transforming. If we had only had a few more days with him! We learned a lot during this trial and will continue to work towards resolving these late-stage challenges in future attempts. We already have more larvae in the hatchery and will work our way back to this point again! In the meantime, Emma will continue to update you on her thesis research as she works to resolve some of their early mortality issues. So much still to learn!
