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Aquaculture

Highlights from the National Shellfisheries Meeting

Every year, the National Shellfisheries Association holds a conference that brings together most of the major players in the shellfish industry – fishermen, aquaculturists, and scientists – to discuss the current research and future directions of the fishery. This year in Monterey, CA, there were over 200 talks and 75 posters of research presented by aquaculturists and scientists from around the world. Researchers come here not only to present their research to colleagues and peers, but also to find new collaborators and exchange ideas. Some of the best ideas in research often come after sharing a beer or two and talking science with another researcher in the field.

Sessions covered all aspects of shellfisheries, from ecology and physiology to disease prevention and genetics, in all the tasty animals that make up shellfish in the US and abroad (oysters, crabs, lobsters, scallops, geoducks, and clams). As a new recruit (the Association’s term for student attendees, taken from the term applied to juvenile shellfish), I had the opportunity to attend this meeting, present my own research, connect with leading scientists, and most importantly, absorb as much information as possible from the talks and posters. Obviously I couldn’t be at every single talk, but here are the top four most interesting and innovative topics I saw presented at the meeting.

Oyster larvae settle partially because of sound – David Eggleston, North Carolina State

These researchers wanted to find out if sounds underwater would affect where oyster larvae would settle. The larvae prefer to settle in an oyster reef, and usually will not settle in muddy sand. To test whether the larvae are influenced by the sounds, the researchers recorded natural sounds from an oyster reef (noisy) and muddy sand (quiet) to see if the larvae would go towards the reef sounds in different lab and field conditions. In the lab, they played the oyster reef sounds in a clean tank (no oyster reef actually present) and saw that the oyster larvae settle when they approach the area where the sound is coming from.   In the field, they played the sounds of the oyster reef over a muddy bottom and were able to “trick” the oyster larvae into settling there! This suggests that there’s more to just chemical cues for these larvae to settle – there’s a sound component, too.

Borrowed from the associated paper: Lillis, A., D. Eggleston, D. Bohnenstiehl. (2014). Habitat-associated estuarine soundscapes: Distinct acoustic characteristics of sub-tidal oyster reefs compared to surrounding soft-bottom habitats. Marine Ecology Progress Series. 505:1-17.

Borrowed from the associated paper: Lillis, A., D. Eggleston, D. Bohnenstiehl. (2014). Habitat-associated estuarine soundscapes: Distinct acoustic characteristics of sub-tidal oyster reefs compared to surrounding soft-bottom habitats. Marine Ecology Progress Series. 505:1-17.

 

 

 

 

 

 

 

 

 

 

Tanner crab larvae respond poorly to ocean acidification – Katherine Swiney, Alaska Fisheries Science Center

These researchers examined how ocean acidification affects the embryonic development of Tanner crabs, a fishery up in Alaska. Their experiment was especially interesting because they manipulated the environment of the crabs for two whole years to encapsulate the entire life cycle from the creation of the egg cells (oocytes) in the mother to the hatching and development of those eggs into larvae. To quantify how the larvae responded to the pH treatments (8.1, 7.8, and 7.5), the researchers measured embryo development, hatching success, and calcification. They found that fewer eggs hatched in the low pH treatments – 87% hatched in the normal pH (8.1), but only 68% hatched in pH 7.8 and 46% hatched in pH 7.5. They also saw that these crab larvae got “stuck” in their first larval stage, which implies that they had enough energy to hatch from the egg, but didn’t have enough energy to grow any larger than that. The study suggests overall that those egg cells in the mother are sensitive to the effects of ocean acidification, possibly because the mother must expend energy to deal with the stressor of low pH and cannot put as much energy into her egg development.

Development of the Tanner Crab - this study looked at the Zoea I.

Development of the Tanner Crab – this study looked at the Zoea I.

 

 

 

 

 

Spider crabs use decoration for different reasons – Katherine Drake, Moss Landing Marine Lab (California State University)

Spider crabs are animals that are able to pull material from their environment to “decorate” their shells. There are a few reasons the crabs do this type of decoration: as camouflage, to blend in with their environment; as food storage, to act as a “pantry” for the crab; and as protection, to use toxic algae to help keep predators away. Her study was in its preliminary stages, but she has designed a study to use computer imaging from SCUBA work to see how similar the crab’s décor is to its environment. Can’t wait to see where that goes!

Would you be able to see this guy on the reef if he wasn't standing on a brain coral? Exactly.

Would you be able to see this guy on the reef if he wasn’t standing on a brain coral? Exactly.

 

 

 

 

 

 

 

 

Ocean acidification affects organismal performance – Scott Applebaum, University of Southern California

We’ve known for a long time that it’s energetically costly for an animal to deal with the effects of ocean acidification (OA), but it’s been difficult for scientists to quantify just how much the energy budget of an animal must change in response to acidic conditions. This study from USC subjected sea urchin larvae to carbon dioxide (CO2) levels of 400ppm and 800ppm to see if the higher levels of CO2 (mild ocean acidification conditions) would change the amount of energy these animals could allocate to different processes. As larvae, the two most important and energetically costly biological processes that have to happen are protein synthesis (makes new parts of the animal) and ion transport (maintains an animal’s internal salt balance). These researchers were able to measure how much energy the animals were consuming during these processes before and after living in high CO2 water. They found that the sea urchin larvae reduced how much protein they were making (34% of their metabolism before OA, 21% after OA) and doubled the energy they were using to transport ions. More work needs to be done with more animals, but this preliminary work confirms that OA causes animals to transport more ions, rather than build more tissue.

Sea Urchin Larvae - beautiful and vulnerable to ocean acidification.

Sea Urchin Larvae – beautiful and vulnerable to ocean acidification.

 

 

 

 

 

 

 

 

 

 

As I always do after a conference, I left re-energized about my own work, filled with new ideas, new collaborators, and new knowledge. Can’t wait to see what the NSA meeting holds next year!

Erin McLean
Hi and welcome to oceanbites! I recently finished my master’s degree at URI, focusing on lobsters and how they respond metabolically to ocean acidification projections. I did my undergrad at Boston University and majored in English and Marine Sciences – a weird combination, but a scientist also has to be a good writer! When I’m not researching, I’m cooking or going for a run or kicking butt at trivia competitions. Check me out on Twitter @glassysquid for more ocean and climate change related conversation!

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