May 15, Rich Kurtz’s research students visited Shu Swamp for a hands-on experience with radiotelemetry. We were able to find both of the radiotagged fish, 101 and 102, still in their respective locations: well upstream in Beaver Brook and along the east bank of the Beaver Lake. We had took two canoes to get to 102’s location. “Team Trout” also helped out by carrying batteries to and from the two RFID stations. I am looking forward to the the team helping out in the field.
We have been monitoring the dam since March for spawning alewives. The season is almost over with probably just one full moon to go. Yesterday afternoon we saw our first alewife swimming up the ramp of the dam. It would reach the top where it was then blocked by an impassable 1 foot vertical lip. Finally it would slip back down to the pool at the base of the ramp to try again. When I went back this morning near high tide I saw two, one of which I managed to net (photo). Unfortunately the photo is poor quality so you can’t see the abrasions on it’s belly and sides, most likely from its struggles up the rough wall of the dam.
Oddly enough I just started seeing a bunch of carp pooling downstream of the dam about a week ago. You don’t normally think of carp as being saltwater fish.. Even more bizarre the carp were also trying to negotiate the dam! I saw the same thing at this time last year at the dam; both carp and alewives attempting to get up the dam. The rest of the year the “saltwater” carp disappear.
Based on my extremely small sample size of N=2, it looks to me like 1) alewives can’t enter the lake unless the tide practically floods over the top, a rare event, 2) the current ladder is worthless (the fish have to positioned perfectly to enter the ladder and even if they do I doubt they could make it up the “rungs”), and 3) they can almost make it to the top by swimming up the ramp; it’s just that last vertical drop that keeps them from success. I would think that it shouldn’t take a great deal of engineering to allow successful entry. For example the ramp could be built up so it starts at the very top and slopes down from there.
Shu Swamp is in its peak spring growth right now. Lots of trout lilies, swamp cabbage and sundry other plants.
Both of the mature trout we tagged on April 10 are still trackable. Both 101 and 102 moved .6 miles downstream from their release point to the pond. We have PIT-tag detections of 102 at the railroad bridge antenna just 7 hours after release. We radiotracked 101 to the pond on April 12. We have further PIT-tag detections of 102 until 1:30 pm April 13. At that time it must have entered the lake and eventually swam at least 1/3 mile (straight line distance) to the east bank of Beaver Lake. Using a canoe we radiotracked it to this point on 4/20 and again on 4/27.
Meanwhile 101 has been on a ramble. According to radiotracking and PIT-tag detections it remained in the vicinity of the railroad bridge until 10:47 am 4/16. On 4/18 4:38 am it was detected at the Beaver Lake dam antenna (.57 miles straightline) and then turned around and was detected back at the railroad bridge antenna 13 hours later. One week later we radiotracked it .8 miles upstream in Beaver Brook where it has stayed as of the latest tracking survey (April 30). It’s current location is well upstream of the original release point.
In summary, 101 has moved a minimum of 1 mile and 102 has moved at least 2.6 miles over the past 3 weeks. You can check out it’s locations in this map:
Eight teachers from Mineola, Malverne, Oceanside, Seaford, East Northport, Farmingdale, and Jericho middle and high schools attended the workshop John Fischer of LITU and I gave at Hofstra last Wednesday. The teachers were quite interested in the TiTC program so I think there may be some recruits for the next season. Here are the teachers trying out their radiotracking skills.