Rising Tide Conservation at Aquaculture America

Rising Tide Conservation researchers Dr. Matt DiMaggio, Dr. Cortney Ohs, and Avier Montalvo recently presented at Aquaculture America in San Antonio, Texas. If you were unable to see our fantastic researchers live, we have the presentation abstracts for you here!

 

DETERMINING PREY PREFERENCE OF FIRST FEEDING MARINE ORNAMENTAL FISH LARVAE UTILIZING FLUORESCENT MICROSPHERES

Cortney L. Ohs*, Isaac Lee, Jason S. Broach, Matthew A. DiMaggio, Craig A. Watson

University of Florida Institute of Food and Agricultural Sciences, Indian River Research and Education Center

As the popularity of marine aquaria grows, potentially more marine ornamental fishes and invertebrates will be harvested from the oceans. Aquaculture of marine species is a sustainable alternative to wild caught individuals and may help to grow businesses and diversify species in production. Experiments were conducted with first-feeding larvae of Reef Butterflyfish (Chaetodon sedentarius), Pacific Blue Tang (Paracanthurus hepatus), African Moony (Monodactylus sebae) and Golden Trevally (Gnathanodon speciosus). The objective was to define prey preferences at first-feeding between rotifers (Brachionus plicatiilis), copepod nauplii (Parvocalanus crassirostris), and ciliates (Euplotes sp.), by marking each prey with a different color of fluorescent microsphere and observing gut contents with a fluorescent microscope. Each fish species showed different prey preferences. Pacific Blue Tang larvae preferred rotifers above ciliates, and ciliates above copepod nauplii. African Moony larvae preferred ciliates and nauplii equally over rotifers. Reef Butterflyfish larvae preferred ciliates over rotifers and rotifers over nauplii. Golden Trevally larvae preferred nauplii over ciliates, and ciliates over rotifers.

This study presents a new understanding of prey preference of first feeding ornamental marine larvae by utilizing fluorescent labelled microspheres. Microspheres are currently used in marine ecology research to trace microplastics throughout planktonic food webs. Ingestion of naked ciliates labeled with microspheres in fish larvae has been previously performed. However, microspheres have not been utilized to examine prey preference and consumption of live feeds. This marks the first use of microspheres in aquaculture with rotifers (Brachionus plicatilis) and copepod nauplii (Parvocalanus crassirostris).

A school of Golden Trevally at the Georgia Aquarium

 

INFLUENCE OF ABIOTIC FACTORS AND FOOD CONCENTRATION ON POPULATION GROWTH OF THE CILIATE Euplotes sp.

Cortney Ohs*; Wesley Freitas da Annunciação; Mônica Yumi Tsuzuki

University of Florida Institute of Food and Agricultural Sciences, Indian River Research and Education Center

Live food organisms used for feeding larval marine fish have received significant research in the past decade. Most of this research and development has focused on rotifer enrichments and feeds, and mass scale production methods for several species of copepods. However, there is a need to investigate other small live food organisms to potentially improve survival and growth of larval fish during the hatchery phase of culture. One potential live food organism is a ciliate. However, there is a dearth of information on optimal production parameters for ciliates. The objectives of this study were to evaluate the influence of abiotic factors including salinity, photoperiod, temperature, aeration, and food concentration on the growth of Euplotes sp. populations. Five replicated small scale experiments were designed and conducted. First, food concentrations of 50, 100, 250, and 500 mg of Protein Selco (INVE) per million ciliates were investigated. Second, salinities of 15, 20, 25, 30, and 35 g/L were investigated. Third, four levels of aeration were investigated. Fourth, temperatures of 17, 20, 23, 26, 29, and 32°C were investigated. Fifth, four photoperiods were investigated.

Results indicated that the optimal range of conditions for production of the ciliate Euplotes sp. tobe a feed concentration of Protein Selco (INVE) of 250 mg per million ciliates, salinity from 20-35 g/L, low or no aeration, temperatures between 26 and 32°C, and a photoperiod between 0L:24D and 16L:8D. Based on the results and observations during this study, we conclude that the ciliate Euplotes sp. has characteristics favorable to mass production including resistance to adverse conditions such as high concentrations of ammonia and very low dissolved oxygen concentrations, they experience high growth and reproduction rates, can grow to very high densities, received nutrition either directly or indirectly from an inert diet, and adapted well to a wide range of salinities and temperatures.

 

RECENT ADVANCES IN THE CULTURE OF THE PACIFIC BLUE TANG Paracanthurus hepatus

Matthew A. DiMaggio*, Eric J. Cassiano, Kevin P. Barden, Shane W. Ramee, Cortney L. Ohs, and Craig A. Watson

University of Florida Tropical Aquaculture Laboratory

It is estimated that over 11 million marine ornamental fishes, representing approximately 1,800 unique species, are sold annually; with the preponderance of specimens resulting from wild capture. Growing interest in marine ornamental aquaculture has served as an impetus for efforts to commercialize new species for the industry and develop novel culture protocols. The Pacific Blue Tang, Paracanthurus hepatus, is consistently among the top twenty species imported into the United States by volume, with all specimens sourced from wild stocks. Captive culture of this species through metamorphosis has not been previously documented and fundamental information regarding reproduction, larval culture, and production techniques is scarce. This study aimed to elucidate methods that would advance our understanding and success with captive propagation of this species.

A total of 50,000 eggs were collected from a single broodstock population (1 male, 2 females) over a three day period in May 2016. The eggs were successively stocked in a 1000 L larval tank for a final density of 50 eggs/L. Beginning at 3 days post hatch (DPH) larvae were fed 3 times daily a diet comprised exclusively of the copepod nauplii (<75 μm, mean ± SD = 5.1 ± 2.3 mL -1 day -1 ) of Parvocalanus crassirostris. At 12 DPH, enriched rotifers Brachionus plicatilis (6.8 ± 3.2 mL -1 day -1 ) were first fed to the tank. At 20 – 21 DPH, powdered feed and first instar Artemia nauplii (1.1 ± 0.7 mL -1 day -1 ) were also added to the diet. Live microalgae (~3:1 of Tetraselmis chuii and Symbiodinium microadriaticum) were added daily to the culture tank throughout the rearing trial. Large mortality events were observed at 7 and 20 DPH corresponding with starvation and flexion, respectively. By 41 DPH, a behavioral change was noted with the majority of the remaining larvae associating with the bottom of the tank. On day 50, the first signs of blue pigmentation marked the beginning of metamorphosis. A total of 27 juvenile blue tangs were cultured during this trial. This effort represents the first successful rearing of this species in captivity and provides important information for future production studies.

Larval development of the Pacific Blue Tang

 

UNTAPPING THE RESOURCE: THE USE OF A MIXED SPECIES EXHIBIT AS A VIABLE SOURCE OF EGGS FOR MARINE ORNAMENTAL AQUACULTURE

Avier J. Montalvo*

The focus of this project was on marine ornamental reef species of importance to Hawaii. Eggs were collected from a partnering institution’s 166,000-gallon public exhibit. Eggs were collected and transported back to the Oceanic Institute (OI), where rearing attempts were conducted and documented. The goal was to culture new species and establish successful rearing protocols which could then be applied to other ornamental species that have not yet been aquacultured. The use of a mixed species exhibit for ornamental egg collection, and mixed-species larval rearing are relatively new approaches in marine ornamental aquaculture. Over the course of the project, a total of 794,760 eggs were collected across 28 collections with representative larvae from three different families of fishes. This led to the successful rearing of six different species, four of which had never previously been reared successfully in captivity. The successful collection, transport, and rearing of eggs from public aquaria gives merit to the mission of Rising Tide Conservation to preserve and protect coral reefs by means of sustainable aquaculture.

Larval development of Klein’s Butterflyfish, Milletseed Butterflyfish, Potter’s Angelfish, Longnose Butterflyfish, Hawaiian Cleaner Wrasse, and the Yellow Tang

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YELLOW TANG PROGRESS AT OCEANIC INSTITUTE

Oceanic Institute of Hawaii Pacific University is making some great headway with rearing Yellow Tangs! Check out the videos of the 36dph and 49dph groups at the Rising Tide Facebook Page: http://on.fb.me/1hEwIUf 

“The Yellow Tang group that is 70dph only has a handful remaining, and just a couple of that handful look like the photo. We are observing a pretty significant gap in development within cohorts, where some fish are extremely stunted compared to their siblings. However, we are really excited to be seeing the dorsal and anal fins forming, which is signaling that the transition to settlement is close! The next group that we have is 49 dph today and many of these fish appear similar in development to our day 70 group. This tank has more than 100 remaining, and they appear really strong, much more lively and active than the day 70 group did at the same age. We are really excited about these 49 dph fish, as they really seem to be doing well. They are even eating frozen cyclopeeze!  Finally, we have another group at 36 dph and there are over 1,000 in that tank. They have started taking artemia and dry feed and we are really optimistic that they will continue to thrive as well!
The biggest changes since our first “success” last year are that we are overlapping the live feeds much longer. The fish are getting broader combinations of copepods, rotifers and artemia, where as last time we relied almost exclusively on copepods (of varying sizes). We also offered dry feed more intensively and at earlier stages, which I think is really helping.”

 

Dr. Chad Callan and the Rising Tide Crew at the Oceanic Institute!

Callan Lab at OI Grad Students: Erin Pereira-Davison


I am a second year graduate student with a graduation date of May 2016. I am currently working with first feeding larval yellow tang primarily during the crucial, first feeding bottleneck. My project deals with different parameters of the rearing environment in hopes of improving feed incidence, growth and survival. My thesis is officially titled
“Effects of Photoperiod, Light Intensity, Turbidity, and Prey Density on Feed Incidence, Growth and Survival in Cultured Larval Yellow Tang *(Zebrasoma flavescens)*.”

To date, I have been able to determine an ideal photoperiod as it pertains to feed incidence which OI has applied to the current groups of 20 day post hatch (DPH)+ yellow tang larvae. Light intensity and turbidity have also yielded significant results that may be applied to larval rearing in the future.

 

Trials pertaining to prey density are ongoing. Once completed, I will run an experiment where all the new found parameters will be combined and compared against OI’s previous rearing parameters in hopes of finding significant improvements in overall survival during first feeding (3-5 DPH)

 

Recently my preliminary photoperiod data was accepted for exhibition at the World Aquaculture Society’s conference in Las Vegas, February 2016. Presenting my research is a great opportunity to share the unique research going on at OI with the help of Rising Tide conservation.

 

On a personal note, I am a Florida native where I completed my undergraduate degree at the University of West Florida under the guidance of Dr. Alexis Janosik and Dr. Toby Daly-Engel. After graduate school I plan on spending some time in the aquaculture industry and then pursue a PhD pertaining to aquaculture, specifically ornamental aquaculture if possible. My husband Ryan Davison is active duty Army and we have two fur babies named Jasper and Icarus.

Callan Lab at OI Grad Students: Emma Forbes

As a student at Hawaii Pacific University I am fortunate enough to complete my Masters in Marine Science while enjoying the gorgeous Hawaiian sunshine. I am originally from New York and graduated from Old Dominion University in 2012 with a Bachelor of Science in Biology. After graduation I took an internship at the Two Oceans Aquarium in Cape Town, South Africa. It was there that my interest in marine ornamental aquaculture was sparked.
My research here is on the assessment of the bacterial community in our live feeds (copepod nauplii) with the addition of probiotics. I am using varying next generation sequencing techniques to assess bacterial communities in the nauplii and potential shifts in bacterial communities with the addition of the probiotics. With this information we are hoping to gain some insight into the bacterial composition of the larval gut and increase larval survival past the first 9 days.
After graduation I am hoping to continue research at OI, because you can’t really go wrong with fish and Hawaii! With luck they’ll let me stick around and I can continue some genomic work with our broodstock and larvae to further advance our understanding of the yellow tang life cycle.
When I am not hugging all of my fish, I can usually be found playing in the ocean. I am an open water swimmer and enjoy getting in the water every chance I can! Last spring we swam 13.2 miles between the islands of Maui and Lanai and are hoping to try again this spring! My biggest focus currently is wrapping up my thesis and enjoying the ocean as much as possible before the “Hawaiian winter” sets in! 

Update on Yellow Tang Research at OI

It’s been about a year since we reported our best success to date with rearing yellow tang, having gotten larvae through to day 83. Since then we’ve had some repeated successes getting the larvae past the first month or so, but never any quite as far along as that cohort from last January. Frustratingly, we seem to have taken a few steps backward again (as seems more common in this field than not), and are now struggling to keep the larvae going past the first week.  We have been revisiting the protocols used from that successful period to ask a lot of questions pertaining to why that worked then, and not now.
Yellow tang OI composite
Yellow Tang larvae reared at OI. A=14 dph, B=24 dph, C=36 dph,
D=45 dph, E=50 dph, F=60 dph. Scale bar = 1mm
OI HPU grad students
Hawaii Pacific University Graduate Students (left to right) Aurora Burgess,
Emma Forbes & Erin Pereira-Davison
I have a great group of ambitious graduate students working on some key aspects of this challenge. Emma Forbes is focusing her research on the microbial community associated with the live feeds and rearing environment, which may have huge effects on larval survival.  Erin Pereira-Davison is investigating several key environmental parameters that could affect first feeding success. She’s looking at the effects of photoperiod, light intensity, turbidity and prey density on first feeding in the larvae. Aurora Burgess will be focusing on the development of the feeding mechanisms in the early larvae, and how this development impacts prey selectivity and feeding ability. She will also be looking at alternative prey items from the wild, compared to our cultured copepods, and testing their use in the culture process.  On top of all this, we have also recruited new broodstock from partner institutions in Hawaii and have recently obtained good spawns from these new stocks.  This will help us determine if perhaps our recent challenges are egg quality-related.
All of these projects working together will hopefully reveal some important insights into the culture processes that will help us better understand the unique requirements of these larvae. Stay tuned for updates from our work, and hopefully some more success to report soon!
 
~Aloha,
The Rising Tide crew at the Oceanic Institute 
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