[CT Birds] More-Gull Barnacle Info

Dennis Varza dennisvz at optonline.net
Wed Feb 29 15:23:15 EST 2012


In response to recent e-mails

One can see this event anywhere from Milford to Norwalk where one can  
get a good view.
Stratford Pt.
Stratford Sea Wall
Stratford Long Beach
Bridgeport Seaside Park
Bridgeport St. Mary's
Fairfield, Penfield Reef
Westport, Burying Hill Beach
Westport Sherwood Is. St. Pk.
Westport Compo Beach
Norwalk Calf Pasture Beach.

Jerry Connolly reported seeing Gulls and Terns feeding off the  
eastern sound of fish larvae.
That is a different phenomenon. It is later in the season and include  
Terns and fish larvae.
The barnacles are usually done before the terns show up.

What to call the "Food"

Plankton refers to any small organism that floats in the water column  
not swim through it.

Phyoplankton are the plankton that are green. When looking at buoy  
data there is a reading of Chlorophyl -A and that gives an estimate  
of the amount of Phytoplankton It generally goes up in the spring  
with the increase in sunlight. and the increase in nutrients from the  
bottom.

The use of the word Bloom implies a refrence to Phytoplankton. This  
may have an effect on the Barnacle Larvae.

Zoplankton are the animal part of the plankton. It can be anything  
form fish larvae, crustacean larvae, worm larvae and assorted  
multicellular organisms.
Then there is micro plankton. Plankton nets have a certain mesh size  
which determine what gets caught or not. At some point they found  
that using a finer net got them a lot more organisms then they  
thought  was there.

Larvae are immature forms of organisms that are generally different  
in morphology than the adults. ie. insect larvae, Frog larvae, Fish  
larvae, Crustacean larvae. often time taxonomic identity is best done  
by looking at the larvae. At one time Barnacles were considered  
mollusks.

Could organisms other than barnacles be involves? Definitely, but it  
would most likely be other places at other times. Blue Crabs? I can't  
imagine crabs producing enough larvae to produce a drift of gulls  
several miles long.

Over the past couple of years Larry Flynn John Barclay and myself  
have been out on Larry's boat with nets and sampled the waters where  
the gulls fed. Every time Barnacle Larvae. John has said that when he  
was working on Greater Scaup, specimens would have their bellies full  
of the larvae.

Barnacles go through several stages. the eggs hatch into a feeding  
stage called the Nauplius After 6 months it transform into the Cyprid  
stage. This is the stage being fed on. It look like tiny clams with  
eyes and antenna, it does not feed and eventually attaches to a hard  
surface. Towards the end of the event one will see the gull along the  
rocky areas where the larvae settle out. The gulls will be scraping  
the rocks with the side of their bills trying to get at them.

This is another case of Birders know one thing Marine Biologists Know  
other things but little interaction takes place.

Dennis Varza
Fairfield



























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