Edmonds Underwater Park Lingcod Nest Census

EUWP Lingcod Nest Site Identification Tags

A key component of the Lingocd Nest Census is the ability to monitor the development of individual egg masses over the nesting season.

The artificial nature of the EUWP and its features greatly facilitate the Census by providing a set of geographic references that allow the location of nest sites and egg masses to be thoroghly documented thus allowing the nest sites and egg masses to be observed repeatly over the nesting season. Named rope trails running both north to south and east to west have been laid out throughout the park dividing the park into rectangles. Many of the features are unique in shape and size and many have been named. The named trails and features are used in identifying the location of nest sites. The pipes, wires, ropes and other materials incorperated into the artifical features make it relatively easy to place identification tags close to nest sites. Placement of identification tags in a natural environment would be very difficult if not impossible due to a lack of usable attachement points.

The Lingcod Census uses two types of nest identification tags (ID Tags) - Annual Census ID Tags and Permanent Nest Site ID Markers.

Annual Census ID Tags

The Annual Census ID Tags are critical to the census effort. They ensure that nests are not double-counted and allow the Census to track individual egg masses over time. Each tag is marked with a nest site ID number and the Census season. The Annual Census ID Tags are randomly assigned to nest sites as the sites are discovered.

Here’s what a current tag looks like. You often see a group of tags from several years indicating a prime nest location. Looks a bit like an anemone with numbers, eh?

Divers, please do not remove any of the Census ID tags. The old tags help identify key nesting sites and help link current observations to those made in past nesting seasons.

The nest tags have evolved over time as various materials, shapes and colors were tested. One of the initial types of tags used was a rock painted green with the ID number painted on it. These tags didn’t work out because the guard fish didn't like the green rocks and turned the rocks over thus hiding the tag numbers. Another problem was that divers would carry the rocks off as souvenirs.

 

 

Here’s a guard fish laying nestled against the tags. We think the guard fish confuse the tags with small plumose anemones. For whatever reason, the guard fish will tolerate small white tags.

 

Permanent Nest Site Markers

Many of the nest sites are used every season. Permanent nest site markers are being placed at such nest sites to help track the use of the sites over time. A variety of markers have been tested with varying success. Both small brass and plastic tags with numbers stamped into the tag surface have been used for these markers. These tags have been attached using plastic wire ties embedded in underwater epoxy. Placement of the permanent markers has been done outside of the spawning season.

Problems in long-term durability/usefulness have been encountered with both types of markers. The brass markers stay clean but are hard to find because of their size. Also, the numbers stamped into them are hard to read underwater. The plastic markers become encrusted with barnacles and other growth that makes them hard to find and obscures the identification numbers.

More work is being done on developing a permanent nest site marking system.

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Updated January 12, 2012
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