FEATURES & ARTICLES
It is Ordered: High Court rules on Second Amendment
by John Marler
SJS Shooting Editor
For the fist time in over two centuries the US Supreme Court has ruled on the meaning of the Second Amendment by affirming the US Court of Appeals overturning of the District of Columbia vs. Heller case. Heller argued the handgun ban in the District of Columbia violated his Second Amendment right as an American. [Read More].
The Predatory Role of Lingcod
by Anne Beaudreau
June, 2008
I am a fifth year graduate student pursuing a PhD in Aquatic and Fishery Sciences at the University of Washington. My research focuses on the predatory role of lingcod, a top fish predator, in nearshore fish communities of the San Juan Archipelago, Washington.
Most of my work so far has been related to the feeding habits of lingcod. I use a non-lethal technique called gastric lavage (a.k.a. stomach pumping) to retrieve lingcod stomach contents and have found that they recover extremely well from this procedure. Since 2004, I’ve collected stomach contents from 1,040 lingcod collected using hook and line in the San Juan Islands. This won’t come as a surprise to anglers, but lingcod eat anything that moves and can fit into their large mouths. Their diets are made up of sculpins, rockfish, herring, sand lance, flatfish, greenlings, lingcod, gunnels, octopus, squid, and a variety of other small fishes. I’ve even pulled a 50 cm dogfish from the stomach of a lingcod that was over 1 m long!
Through this work, I’m trying to gain a better understanding of the potential impact of lingcod predation on rockfish populations, which have been at low levels in the San Juans for some time. Are lingcod eating enough rockfish to prevent them from recovering? My work has shown that lingcod are eating mostly small rockfish, including Puget Sound rockfish (a small species that isn’t fished for) and juveniles of other rockfish species, including copper rockfish. I have also discovered that lingcod may be eating 5-10 times more rockfish in marine reserves than in the surrounding non-reserve areas. Without more information on rockfish sizes and numbers in these areas, it is hard to say what effect lingcod are having.
Another key question of my research is whether marine reserves in the San Juan Channel will protect and enhance lingcod populations to ultimately provide improved fishing opportunities outside the reserve boundaries. During the summer 2007, I surgically implanted acoustic transmitters into nine lingcod in the marine reserve, which is closed to bottomfishing, on San Juan Island (between Friday Harbor Laboratories and Point Caution) and tracked their movements over three months. I found that lingcod showed a lot of individual variation in their behaviors, and all except one never left the reserve during the summer. Overall, fish tended to have “home” areas where they would remain stationary for several hours at a time. Depending on light and tidal conditions, they would move deeper or shallower and then return to their home sites. A single male lingcod made regular excursions every 4-5 days from the nearshore (20-30 m depth) to the middle of the San Juan Channel (160 m depth) and back, presumably for feeding. Several individuals were regularly found moving within nearshore areas as shallow as 2 m!
A related question is whether lingcod make seasonal movements that differ from their small-scale daily activities. To address this question, I started tagging lingcod with the external plastic spaghetti tags during summer 2007 and made follow-up trips to tag and recapture fish in November, February, and May.
It’s surprising, but we still know very little about lingcod populations in the Puget Sound area. It’s thought that they have recovered from low abundances in the 1980s and ‘90s, but there is little current information about their abundance and distribution in this region. Through our tag recapture data in the San Juan Channel, I’m hoping to gain a better understanding of population size and structure at different sites. I have six main sites in the San Juan Channel – 2 marine reserves on San Juan Island and Shaw Island and 4 non-reserve areas between Pear Point and Point Caution. The fish we’ve caught ranged in size from 30 cm (0.2 kg) to 115 cm (15.5 kg). I believe that marine reserves are working well for lingcod. Our catch rates are higher in the protected areas and there are many more large females. My hope is that through reproduction, lingcod inside the marine reserves might provide a source of new recruits to surrounding areas that are open to fishing.