Nikki Durkan: Parasites Abound, June 29, 2015

NOAA Teacher at Sea
Nikki Durkan
Aboard NOAA Ship Oscar Dyson
June 11 – 30, 2015

Mission: Midwater Assessment Conservation Survey
Geographical area of cruise: Gulf of Alaska
Date: Monday, June 29, 2015

Weather Data from the Bridge:
Wind speed (knots): 8.25
Sea Temp (deg C): 10.59
Air Temp (deg C):  10

Science and Technology Log:

Parasites – some lurk inside our bodies without us knowing and some could even have an influence on our personalities. One of my favorite Radio Lab episodes describes research conducted on this subject. National Geographic Magazine also published a feature article I found quite interesting – Zombie Parasites that Mind Control Their Hosts.  In addition to capturing our interest because of their sci-fi-like existence, parasites may also be utilized to study ecological interactions.  Parasites a fish picks up throughout its life can indicate information about where the fish has traveled – these co-dependent organisms serve as biological tags that scientists can then interpret.

Nematodes on Pollock Liver - most of the Pollock we caught have had these in their guts.

Nematodes on Pollock Liver – most of the Pollock we caught have had these in their guts.

Parasites often require several hosts to complete their lifecycles and one nematode that can infect Pollock (and humans incidentally) is Anisakiasis.  While I love sushi, raw fish can pose serious risk to our health.  “Sushi-grade” labels, similar to the ubiquitous “natural” labels, do not meet any standardized specifications. However, the FDA does set freezing requirements for the sale of raw fish that commonly possess parasites…so enjoy your sushi🙂

The pathobiologists at the Alaska Fisheries Science Center are currently investigating the impacts certain parasites may have on Pollock. While many species of parasites have been recognized, we still have a lot to learn about their impact on populations and ecosystems. Scientists are attempting to identify those that are likely to influence the booms and busts that can occur within the Pollock populations. More specifically, their current research centers around a microsporidian (pleistophora sp.) that lives within the muscle tissue of Pollock and may impact the fishes ability to swim and breed. (AFSC Pathobiology)

Microsporidian (pleistophora sp.) marked with asterisk Photo Credit: NOAA

These critters are found in most Pollock catches as well - they are sometimes called sea lice.

These critters are found in most Pollock catches as well – they are also called sea lice.

Sometimes ships pick up parasites too! The introduction of invasive species to fragile ecosystems is one of the leading causes of extinction and ballast water is the number one reason for the distribution of aquatic nuisance species. The Great Lakes region serves as a warning about the devastation ballast water can inflict on an ecosystem. Ships can transport ballast water from one region to another and then release the ballast water (along with numerous non-native organisms). No longer encumbered by natural predators or other environmental pressures that help to keep populations in check, the invasive species can flourish, often at the expense of the native species. NOAA has implemented strict guidelines for the release of ballast water to limit the spread of invasive species.  The Oscar Dyson also uses a lot of oil to keep all the working parts of our engine room functioning, but some of this oil drips off and collects in the bilge water. This oily bilge water is then separated and the oil is used in our trash incinerator (all garbage with the exception of food scraps is burned in the incinerator).  Thanks to our Chief Marine Engineer, Alan Bennett, for taking me and Vinny on a tour of the ship.

Thanks, Allan!

Thanks, Allan!

Personal Log:

Fortunately, after three weeks of being splattered with all parts of a Pollock you can think of and eating my fair share of fish, I am currently free of fish parasites…to my knowledge! Our wonderful chefs, Arnold Dones and Adam Staiger, have been cooking healthy, varied meals for 32 people over the course of three weeks – this is no small feat!  The soups are my favorite and have inspired me to make more when I return home. I know from camping experiences with my students and living at a boarding school campus, that food is directly connected to morale.  Last night, the chefs spoiled everyone with steak and crab legs!

Chef Adam Staiger is full of smiles!

Chef Adam Staiger is always full of smiles!


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