by Admin | Jun 5, 2014 | Conservation, Fish, Science, Tanks
Figure1. The new larval rearing room at TAL; showing the 120 Ltanks used to grow octopi in. We've also recently tested our fish species in them which we'll talk about next time. At the Tropical Aquaculture Lab in Ruskin, we’ve been running into lots of bottlenecks in the early larval development of some of the Rising Tide species we’ve been working on. We believe these issues were exacerbated due to our current larval rearing systems being inadequate to provide the pristine water quality necessary for larvae to survive. Because of this, we’ve spent the past several months upgrading our facilities, to what we believe will be an important step toward significant advancements in captive raised marine ornamentals. Figure 2. 22 day old common octopus paralarvae Upon nearing completion of the new system, we were approached by Mote Marine Laboratory’s cephalopod specialist Brian Siegel; their common octopus (Octopus vulgaris) had spawned, and they were curious if we would be interested at giving them a go. Rising Tide’s focus is primarily on the captive propagation of marine fish species, but we thought this would be a great way to test out our new larval rearing system. Common octopi have been reared in captivity at several institutions around the world, but with very low survival, believed to be due to poor water quality and nutrition. We’re hopeful the improvements we’ve made to our system will allow us to have some success with these challenging cephalopods. Cephalopods have incredible abilities to adapt to their environment using chromatophores, which are pigment-containing and light-reflecting organelles found within their cells. They allow the octopi to communicate as well as camouflage to their environment. Even as paralarvae, these common octopi can create beautiful patterns with their chromatophores, as seen here: Common octopus paralarvae have a voracious appetite for crustacean zoea in their natural environment, and have been successfully reared by substituting with Artemia nauplii as a prey item throughout development. By providing them with a constant supply of pristine seawater along with microalgae and Artemia nauplii, we’ve reached 28 days post hatch today. We’re hopeful they will remain strong enough to survive to settlement. The Rising Tide team at the Tropical Aquaculture Laboratory 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 Admin | May 15, 2014 | Conservation, Fish, Science, Tanks
Figure 1. A 35 day old milletseed butterflyfish larva with morepronounced dorsal spines. During this recent trial, larvae displayedgreater development in a shorter period of time.It’s been a while since our last milletseed butterflyfish post but, not to worry, I’ve been very busy conducting a variety of replicated experiments to better understand their larval requirements. From those experiments, I’ve learned several important things about raising the milletseed butterflyfish. From our previous examinations we knew that nauplii of the copepod Parvocalanus crassirostris could be used as a first feed, however, in clear water only about 50% of larvae were feeding. After exploring the literature, I decided to test a variety of parameters including algal turbidity, prey density, prey selectivity, tank size, light intensity, and stocking density in order to increase feeding performance. Figure 2. A 35 day old milletseed butterflyfish larva with less dorsal spine development and more elongate shape.From these studies I initially learned that the milletseed butterflyfish do not identify rotifers (Brachionus plicatilis) as prey throughout larval development. Additionally, testing revealed that different stocking densities, light intensities, and tanks sizes didn’t have a significant effect on feeding incidence or performance of the larvae. However, what did enhance feeding was the addition of algae (T-ISO) to the tank; which increased the feeding incidence to about 90%. Another interesting result was that feeding incidence was the same at 1 individual/mL as at prey densities up to 20 individuals/mL. While the rearing of milletseed butterflyfish to the juvenile phase has not been accomplished yet, this information is crucial for the optimization of culture methods of the milletseed butterflyfish. By improving early larval feeding we can increase early larval survival and promote development, increasing the likelihood of rearing larvae to settlement. 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
