by Admin | May 22, 2014 | Conservation, Fish, Industry, Science
Figure. Photos of Colurella adriatica;a potential new live feed for bothmarine and freshwater fish larvae.This post is in response to requests for more information about Colurella adriatica. As previously stated, we’ve examined salinity and found that although they tolerate a wide range, optimal performance is at 15-20 g/L (ppt). For feeding marine fish larvae this is likely going to be the culture salinity as acute acclimation to full strength seawater is good and this will save on salt. Colurella also grows well at 5 g/L and therefore when growing them for freshwater fish, this is the recommended salinity. Thus far, attempts to grow Colurella in 0 g/L freshwater have yielded poor results. The only other culture parameter tested so far has been diet. An industry partner works as a microbiologist and isolates bacteria. He had some freeze-dried bacteria that he wanted us to test. When solely fed freeze-dried bacteria the Colurella populations survived. When compared to those Colurella fed algae paste (Nanno 3600™; Reed Mariculture), the ones fed freeze-dried bacteria initially grew better than those fed paste. However, after 4 days the Colurella fed paste had significantly greater growth. The results of this trial are still being evaluated, as is optimal diet, but Colurella’s ability to be fed, and survive on, freeze-dried bacteria seems feasible. Other culture parameters haven’t been tested yet, but we keep our populations at ~78° F with gentle aeration and can reach ~500 rotifers per mL with a population growth rate half of what is achieved with Brachionus sp. rotifers. Hopefully, once we know more about this species we can increase the population density and growth rate. As stated in a previous post, Colurella has been fed to and consumed by a number of marine fish larvae. In fact, it is easier to mention the one that has not consumed it: green chromis. Digestibility has been an issue for us when using Colurella as prey for marine fish larvae. We've actually seen live, undigested Colurella being passed through the gut of marine fish larvae. After talking with Patrick Sorgeloos, his suggestion was to feed less and increase the residence time in the gut. We'd always fed high densities. One of the unique attributes of Pacific blue tang larvae is their ability to survive heavy water movement (usually in the form of aeration), even to the point of being unable to feed (more on this in a future post). One of the tests we’ve run to increase digestion was to feed them Colurella followed by periods of heavy aeration so they couldn’t feed. What we found were digested Colurella in the gut of Pacific blue tang larvae. The results were encouraging and recent tests have focused on ways to increase residence time of Colurella in the gut of marine fish larvae. Digestibility of Colurella is not a problem for freshwater fish larvae. To date, we've fed them to bala shark, dwarf gourami, lemon tetra, and red-eye tetra larvae and they've all survived. Recently a population of Colurella was supplied to a freshwater fish farmer in the hopes of more advantageous results during larval rearing. Perhaps the most exciting information is that in the next few weeks we’ll be awarded a grant to look at the culture conditions and larval feeding of Colurella (and Oithona colcarva; our marine cyclopoid copepod). Whether this will be in the form of hiring someone or promoting someone at our facility remains to be seen, but having someone focused solely on answering these questions will help us obtain valid information quickly. The Rising Tide team at the Tropical Aquaculture Laboratory by AquaNerd | May 13, 2014 | Conservation, Fish, Industry, Science
Wrasses are arguably the most diverse group of fish in the ocean, and according to a new journal entry on the Ocean Science Foundation, a new and very flamboyant member is being added to that group. To make the news even more exciting, the species was discovered not by scientific exploration, but by eagle-eyed professionals in the aquarium industry, further adding to the importance of the hobby to the scientific and conservation communities. In July of last year, Greenwich Aquaria imported a beautiful pencil wrasse from Kenya, quickly noticing the fish was different. They shared the images of the fish on their social media channels, at the same time claiming the fish was a new species. Almost a year later, that claim was confirmed in the scientific article penned by Benjamin Victor and John Randall, which we linked to above. The new species, named Pseudojuloides edwardi after Jason Edward from the aquarium store, differs from its two sibling species, P. severnsi from Indonesia and the Mauritian P. by AquaNerd | May 6, 2014 | Corals, Equipment, Tanks, Technology
Have you ever heard of someone singing the praises of a product for such a small, seemingly insignificant detail? Well, we’re doing just that for the Fluval SEA additives, which have impressed us with their bottlecaps alone. Dosing with aquarium supplements has always been a bit of a guessing game. The instructions are always a little iffy, and measurements have always been eyeballed. To avoid all of the confusion, however, Fluval did something special with their line of supplements, and it’s one of those fine details that will likely go unnoticed by many. To help dose their products, Fluval included a graduated plastic cap into the overall design of their SEA additive line. In a broader view of our daily lives, this isn’t anything special 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.
