How SMURFs help us learn about fish recruitment

Apr 30, 2016

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How SMURFs help us learn about fish recruitmentMonitoring timing and strength of recruitment for kelp forest and rocky reef fishes requires a special tool and standardized protocol. Along the west coast of the U.S., standard monitoring units for the recruitment of fishes or SMURFs have been used to capture and quantify recruiting fishes. SMURFs are artificial fish habitat made out of plastic garden fence mesh that are attached to moorings placed just offshore of rocky reefs where fish recruit. By using SMURFs over a number of years, scientists can observe patterns of fish recruitment and begin to make correlations between fish recruitment and oceanographic conditions. Below is a SMURF with several small rockfishes swimming around it (Photo Credit Dani Ottman).
                
Fish are sampled by free divers with a hinged net. The free divers envelop the SMURF with the net, detach the SMURF from the mooring line, and bring the whole SMURF (and all the fishes that have recruited to it) onto a boat for sorting. See free diver netting a SMURF below(Photo Credit Dani Ottman).                
 
This week a team of scientists from Oregon Department of Fish and Wild Life, the Oregon Coast Aquarium, and Oregon State University deployed 4 SMURFs and moorings at Otter Rock Marine Reserve and in Cape Foulweather for the upcoming recruitment season. I assisted in these deployments and will be collecting fish from SMURFs. I'll compare their early life history characteristics of these newly settled SMURF rockfish with older settled rockfish that I'll catch on reefs by SCUBA diving. 
Here Dr. Kirsten Grorud-Culvert (OSU) and I prep the mooring for deployment (Photo Credit Peter Pearsall Oregon Coast Aquarium).
                
We first throw the surface buoy in the water. Then pay out the mooring line with the SMURF, oceanographic instruments, and subsurface floats(Photo Credit Peter Pearsall Oregon Coast Aquarium).                
 
Finally, we toss the anchor into the water(Photo Credit Peter Pearsall Oregon Coast Aquarium):
                
Anchor away!(Photo Credit Peter Pearsall Oregon Coast Aquarium)                
 
Now all we have to do is come back every two weeks to free dive and catch fish. Stay tuned for photos and video of this summer's SMURFing and diving collections!

Here is a picture of my lab mate with a recently cleaned SMURF. In the background you'll see the many rocks that located in Redfish Rocks Marine Reserve in Port Orford.

Sue Palsbo, PhD, Su, and 2 others like this.

3 comments

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Renato Correia

Hi Will, I'm building SMURFs traps too for my PhD research and I'm facing some kind of space problem. Well, I'm using dimension provided by Ammann paper, but I think they are too big. By you picture I think your SMURF has a nice and suitable size. Can you tell me exactly how big they are ?

Aug 24, 20160

Will FennieResearcher

Hi Renato, They are 1m in length and and 35 cm in diameter. I'll post a picture of a SMURF next to my lab mate for scale.

Aug 29, 20160

Renato Correia

Nice man. It's strange because mine had the same length and diameter and looked bigger. I should perform a trial this month here in Brazil with one a little bit small.

Sep 10, 20160

Will FennieResearcher

Excellent questions! The SMURFs are located at 1m depth because scientists in central California determined that the highest catch rates of SMURFs were 1m below the surface. They compared that with 1m above the bottom and 8m above the bottom (all SMURFs in this study were moored at depths of 17m). While having the SMURFs 1m below the surface does miss some of the benthic recruiting species, it captures the majority of kelp forest and rocky reef recruiting species. The major environmental conditions we are trying to correlate with recruitment are upwelling and relaxation events. Upwelling occurs when strong northwest winds blow for several days. This moves surface waters offshore and brings cold, nutrient rich, salty water to the surface. When these winds relax or blow from the south, surface water is moved inshore. We have instruments that measure temperature and salinity. Cold water temperature and high salinity are indicative of upwelling periods while warmer, fresher water is indicative of relaxation periods. The larger project (of which my sampling is just a small piece) monitors year to year differences in oceanographic conditions and fish recruitment. By accumulating a long term data set of fish recruitment we can understand how the environmental conditions affect recruitment of fishes to Oregon's nearshore reefs.

May 03, 20160

Sue Palsbo, PhDBacker

I think I remember learning that different bodies of water have salinity signatures, with colder (deeper) water having higher salinity. pH may have been part of the signature, as well. Are you seeing changes in the signatures with acidification and warming temps over time?

May 04, 20160

Will FennieResearcher

You are correct that different water masses have different signatures and that colder, deeper water is saltier. I can't speak too much about what the SMURF moorings instruments have seen over time (yet!), but there are a few groups who have some long term data sets who could answer those questions. Bruce Menge's lab at OSU had several offshore and intertidal instruments that looked at similar questions. Francis Chan's 2008 study, in collaboration with the Menge lab at OSU, looked at oxygen records off Oregon's coast over the last 50 years and saw an emergence of low oxygen water starting in the 2000s. Some really interesting and alarming studies have suggested that climate change will alter the timing, duration, and intensity of upwelling. Jack Barth's (OSU) 2006 study found that in 2005, upwelling onset was delayed by 30 days, which caused dramatic changes in temperature, nutrients, primary productivity, and lead to one of the worst years in recruitment of intertidal organisms. With the warm blob's appearance last year, and the strong el Niño this year I am very interested to understand how oceanographic conditions affect the early life stages and recruitment of rockfishes so we can predict the impacts future climate change on rockfishes.

May 09, 20160

Sue Palsbo, PhDBacker

Dang. Is your doctoral thesis to build and test a multivariate model?

May 12, 20160

Will FennieResearcher

I am going to give it a shot, but it is more of the high risk high reward aspect of my dissertation. Linking the oceanography to the biology is my primary goal.

May 22, 20160

Sue Palsbo, PhDBacker

What are the data you are collecting through instrumentation? Can you tell us how you decide to position the SMURF in the water column?

May 03, 20160

About This Project

How oceanographic conditions affect the growth, diet, and survival of juvenile rockfish

Oregon State University

Rockfish are important fishery species on the U.S. West coast. Many rockfish species were overfished in the 1980s, but management actions are rebuilding their stocks. Climate change threatens to dramatically alter the ocean ecosystems rockfishes inhabit and may reverse the efforts managers have made to protect these fishes. It is important to understand how changes in ocean conditions will affect the most vulnerable stages of rockfish to predict how their populations will fare in the future.