//
you're reading...

Biology

Unsuccessful Octo-cultures

Garrido, D., et al. “Fatty acid composition and age estimation of wild Octopus vulgaris paralarvae.” Aquaculture (2016). V. 464, pp. 564-569. 

Marine farming, termed ‘aquaculture’ is a way to supply sea food to consumers without catching it from the natural environment.   Of course, arguments can be made about possible benefits and consequences of aquaculture, but let us put those aside for now and focus on the science behind aquaculture.

Figure 1: Octopus is a common fishery catch. https://www.flickr.com/photos/azchael/16622957352

Figure 1: Octopus is a common fishery catch. https://www.flickr.com/photos/azchael/16622957352

A main goal of aquaculture is to farm creatures that are comparable to what is found in nature.   Natural environments are complex though, so mimicking the conditions correctly in a cultured environment can be tricky, making it difficult to raise animals that compare to those from the wild.   For example, many attempts to culture Octopus vulgaris, a popular fisheries catch (figure 1), have been unsuccessful during early stages of growth.  The failure to raise O. vulgaris to adulthood (figure 2) in culture hinders any chance of successful aquaculture.

Figure 2: Octopus Vulgaris: https://commons.wikimedia.org/wiki/File:Octopus_vulgaris_3.

Figure 2: Octopus Vulgaris: https://commons.wikimedia.org/wiki/File:Octopus_vulgaris_3.

To identify the cause of mortality of laboratory O. vulgaris paralarvae (the young octopuses), scientists designed a study to compare the fatty acid (FA) component of laboratory raised paralarvea with wild paralavae of the same age.  The idea behind the study is that if they can identify a difference in FA then they could determine the source, which would enable them present a solution and potentially have successful aquacultures of O. vulgaris in the future.   The study design is unique from previous work on this problem because researchers looked at individuals for data, as oppose to previous studies on groups, and they will only be comparing cultured paralavae with wild paralarvae of equivalent age.  These two factors set this study apart because it can capture the natural variation in the wild population and because it is comparing wild and cultured paralarvae while they are at the same growth stage, respectively.

Methods: 

O. vulgaris paralarvae samples were collected in October 2013 from Ria de Vigo on the R/V Mytilus.    Only ten wild specimens were collected and brought back to the lab for analysis because of their wide distribution in the water column.

Figure 3: octopus beak (right side) example. https://en.wikipedia.org/wiki/Cephalopod_beak

Figure 3: octopus beak (right side) example. https://en.wikipedia.org/wiki/Cephalopod_beak

In the laboratory dorsal mantle length (body length) was measured.  In addition, age was determined based on the length of the lateral hood surface (LHS), which grows in daily increments, on the beak (figure 3).  The growth increments are visible with the right combination magnification, transmitted light, and 3D imagining.  They are counted to determine the age of the paralarvae.   The ages of wild paralarvea were used as the selection criterium for the cultured paralarvae used in the analysis.

Wild and cultured paralarvae fatty acid composition was determined using robust analytical techniques and complex laboratory instruments.  Researchers compared their data and the results of similar studies using principal component analysis to identify patterns in their findings.

Results:

Researchers were able to isolate only six of the ten beaks during the extractions due to the delicacy of the technique. The undamaged group of six ranged between 6 and 8 days old.   The scientists determined that for their purposes, using LHS as a proxy for age is more accurate than determining age from a laboratory determined formula because it does not rely on specific environmental conditions. It also removes the assumption that all hatchlings are the same size, which is important because hatchling size may vary  as a function of diet, temperature, and the mother’s health, for instance.

From the FA statistical analysis three groups were determined: hatchlings, cultured paralarvae, and wild paralarvae.    Scientists observed that the difference between wild and cultured specimen increases with age.     In other words, the hatchlings from culture are similar to the wild paralarvae, however, as they grow into paralarvae in the lab their fatty acid make up differs more and more from the wild specimen of the same age.  Scientists were able to eliminate methodology as the cause of their observations because  the results were similar to other studies.

There were two main differences in fatty acid composition between wild and laboratory paralarvae.  First, the paralarvae from the culture had lesser amounts of DHA than the wild paralarvae.  Second, culture paralarvae had an additional fatty acid, called 18:3n-3, which was not found at measurable amounts in the wild paralarvae.

Discussion:

The difference in FA between cultured and wild paralarve that appears with age is likely a result of their diet. In the laboratory, paralarvae mostly consume Artemi, however, in the wild, paralarvea prefer decapod crustacean zoeae, which Artemi is not. It is apparent that the Artemi diet does to supply a sufficient amount of DHA to the laboratory paralarvae population.  The diet does however appear to supply 18:3n-3.  Further study is needed to address just how much DHA is needed in culture diets to mimic the wild ones, currently, the diets are insufficient at accommodating nutritional needs during early growth stages  Once more information is gathered, successful aquacultures of O. vulgaris could be in the future.

Discussion

No comments yet.

Post a Comment

Instagram

  • by oceanbites 2 months ago
    Happy Earth Day! Take some time today to do something for the planet and appreciate the ocean, which covers 71% of the Earth’s surface.  #EarthDay   #OceanAppreciation   #Oceanbites   #CoastalVibes   #CoastalRI 
  • by oceanbites 3 months ago
    Not all outdoor science is fieldwork. Some of the best days in the lab can be setting up experiments, especially when you get to do it outdoors. It’s an exciting mix of problem solving, precision, preparation, and teamwork. Here is
  • by oceanbites 4 months ago
    Being on a research cruise is a unique experience with the open water, 12-hour working shifts, and close quarters, but there are some familiar practices too. Here Diana is filtering seawater to gather chlorophyll for analysis, the same process on
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  on  #oceanbites  we are featuring Hannah Collins  @hannahh_irene  Hannah works with marine suspension feeding bivalves and microplastics, investigating whether ingesting microplastics causes changes to the gut microbial community or gut tissues. She hopes to keep working
  • by oceanbites 5 months ago
    Leveling up - did you know that crabs have a larval phase? These are both porcelain crabs, but the one on the right is the earlier stage. It’s massive spine makes it both difficult to eat and quite conspicuous in
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring Cierra Braga. Cierra works ultraviolet c (UVC) to discover how this light can be used to combat biofouling, or the growth of living things, on the hulls of ships. Here, you
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Elena Gadoutsis  @haysailor  These photos feature her “favorite marine research so far: From surveying tropical coral reefs, photographing dolphins and whales, and growing my own algae to expose it to different
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  on Oceanbites we are featuring Eliza Oldach. According to Ellie, “I study coastal communities, and try to understand the policies and decisions and interactions and adaptations that communities use to navigate an ever-changing world. Most of
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Jiwoon Park with a little photographic help from Ryan Tabata at the University of Hawaii. When asked about her research, Jiwoon wrote “Just like we need vitamins and minerals to stay
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring  @riley_henning  According to Riley, ”I am interested in studying small things that make a big impact in the ocean. Right now for my master's research at the University of San Diego,
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Gabby Stedman. Gabby is interested in interested in understanding how many species of small-bodied animals there are in the deep-sea and where they live so we can better protect them from
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Shawn Wang! Shawn is “an oceanographer that studies ocean conditions of the past. I use everything from microfossils to complex computer models to understand how climate has changed in the past
  • by oceanbites 7 months ago
    Today we are highlighting some of our awesome new authors for  #WriterWednesday  Today we have Daniel Speer! He says, “I am driven to investigate the interface of biology, chemistry, and physics, asking questions about how organisms or biological systems respond
  • by oceanbites 8 months ago
    Here at Oceanbites we love long-term datasets. So much happens in the ocean that sometimes it can be hard to tell if a trend is a part of a natural cycle or actually an anomaly, but as we gather more
  • by oceanbites 8 months ago
    Have you ever seen a lobster molt? Because lobsters have exoskeletons, every time they grow they have to climb out of their old shell, leaving them soft and vulnerable for a few days until their new shell hardens. Young, small
  • by oceanbites 9 months ago
    A lot of zooplankton are translucent, making it much easier to hide from predators. This juvenile mantis shrimp was almost impossible to spot floating in the water, but under a dissecting scope it’s features really come into view. See the
  • by oceanbites 9 months ago
    This is a clump of Dead Man’s Fingers, scientific name Codium fragile. It’s native to the Pacific Ocean and is invasive where I found it on the east coast of the US. It’s a bit velvety, and the coolest thing
  • by oceanbites 10 months ago
    You’ve probably heard of jellyfish, but have you heard of salps? These gelatinous sea creatures band together to form long chains, but they can also fall apart and will wash up onshore like tiny gemstones that squish. Have you seen
  • by oceanbites 11 months ago
    Check out what’s happening on a cool summer research cruise! On the  #neslter  summer transect cruise, we deployed a tow sled called the In Situ Icthyoplankton Imaging System. This can take pictures of gelatinous zooplankton (like jellyfish) that would be
  • by oceanbites 11 months ago
    Did you know horseshoe crabs have more than just two eyes? In these juveniles you can see another set in the middle of the shell. Check out our website to learn about some awesome horseshoe crab research.  #oceanbites   #plankton   #horseshoecrabs 
WP2Social Auto Publish Powered By : XYZScripts.com