Saturday, February 24, 2007

Update on Over-Winter Striped Bass


I've heard from lots of readers asking for an update on over-winter striped bass in Rhode Island. Yesterday, Captain Al Anderson, charter boat captain and the king of winter bass fishing on the Thames River in CT, contacted me to share an article he wrote on this subject for the Underwater Naturalist, a publication of the American Littoral Society. Rather than try to summarize, I reprinted the text of Captain Anderson's fascinating article below. Thanks Captain!


I have been fishing a few times in the Providence River this winter. November, December and early January were exceptionally mild, and so fish seemed to be spread out throughout the river and were difficult to catch. On New Year's Eve Day (Dec 31st), I observed a large school of adult menhaden in the Seekonk River with bass pushing them (but failed to catch any).


More recently, fiercely cold weather has concentrated schools of bass in the Upper Providence River and Water Place in the vicinity of the Manchester Street Power Station. When not iced over, I have had good success there.


I'd say about 30% of the fish I caught had the sores, lesions, and fin-rot I described last January. I still don't know what that disease is, but the few biologists I have spoken to say they do not think it's mycobacteriosis which has infected fish in the Chesapeake. The common explanation is that these winter fish get beaten up and undernourished in winter, and are susceptible to infection. For what it's worth, I saw no diseased fish between March and November '06. I'm still very concerned about it, though, since no one knows for sure what it is.

Thanks for reading, and feel free to contact me at jtorgan@savebay.org.

See some recent pics below:











Tag Recapture of Thames River Over-Winter Stripers
by CAPT. AL ANDERSON
Vol. 27, No. 1 15

Several years ago I learned the Thames
River in Norwich, CT, hosted tremendous
numbers of over-wintering striped bass.
This raised a slew of questions, to which I
could find no answers.


Recognizing a unique situation, I embarked on a project
of tagging these fish in the hopes of learning
more about their biology. Since then
I've confirmed some of what we know, as
well as creating questions only others will
be able to answer.

Over a period of seven years, beginning
in 1997, 111 trips were made to the
Thames to catch, tag and release overwintering
striped bass from November
through April. During this period 6,569
stripers, mostly juveniles, were tagged for
the American Littoral Society (ALS). The
bulk of the fish were caught in the river
channel north of the Pequot Bridge to the
basin area at Chelsea Landing below
downtown Norwich.

Unseasonably warm weather in the Fall
of 2001 allowed increased effort to nearly
double the numbers marked that season.
In 2002, charter trips to the river nearly
tripled, undoubtedly due to increased
awareness by the angling public. When
asked if I've ever recaptured one of these
6,569 fish, the answer is no! This hasn't
happened yet, but many have been recaptured
in the Thames and elsewhere by
other anglers.

Thames River


Three major Connecticut rivers carry
freshwater into Long Island Sound. The
largest, the Connecticut, with a drainage
basin of 11,200 sq. miles, is followed by
the Housatonic River (1,930 sq. miles),
and the Thames (1,400 sq. miles). Both
the Shetucket and Yantic Rivers feed the
Thames River (formerly called the
Pequot), which collectively drain 510 sq.
miles. Only the Thames River reportedly
hosts significant numbers of over-wintering
striped bass, and there is no evidence
of a striper spawning population there.

Over-Wintering

It appears that 30 or 40 thousand or more
striped bass have congregated here each
winter in recent times. In 1999 Bob
Sampson, Jr. and I used an underwater
video camera to survey an area in the basin
at Chelsea Landing. In it was a school of
fish 250 yds. long by 15 yds. wide by 10
yds. deep. Sampson calculated that approximately
30,000 fish made up this school,
which he profiled in a story for a N.E.
Edition of The FISHERMAN magazine.
Furthermore, my research uncovered a
Boston newspaper article reporting that
following a warm, wet Southeaster that
broke up river ice, 20,000 stripers were
haul-seined at Chelsea Landing over several
days in February, 1729. Tremendous
numbers of fish undoubtedly over-wintered
here long before colonial times.

Several features may facilitate overwintering
here, including water depths
approaching 48 ft., significant daily tidal
flushing (2.7' rise), proximity (14 miles)
to the deeper waters of Long Island
Sound, flow of freshwater from the
Shetucket and Yantic Rivers, and high
late-season forage abundance (vertebrate
and invertebrate) due to connection with
several large tidal coves and creeks.

Captain Anderson runs a charter fishing
boat out of Snug Harbor, RI. He concentrates
on striped bass but also goes offshore
for tuna, cod, and other prey. He can be reached at ahatuna@aol.com


Underwater Naturalist
Catch, Tag & Release

Fishing occurred by means of rod and
reel from several outboard powered boats
trailered to various river launching ramps.
Tackle was either conventional, spin or fly
rod. Single hook lures such as bucktail
and plastic tail jigs, small tubes and flies
were used to minimize tissue damage or
injury, as initial attempts ('97) using
multi-hook plugs were found to be highly
unsatisfactory.

The bulk of the fish were caught along
river channel edges with conventional
tackle trolling mini-umbrella frames
sporting several single hook lures on relatively
short lines, which resulted in short
fight times. Fish boated were placed on a
tagging board and eyes quickly covered
with a wet towel to minimize any stress
due to thrashing. "Lock-on" loop tags
were placed in the back between the anterior
and posterior dorsal fins.

Time out of water for unhooking, tagging,
measuring, and releasing was kept to
a minimum. Weights were not taken, but
estimated from a published striped bass
length to weight chart.

Seasonal surface water temperatures
ranged from the low 50's F to low 30's F.
Upper river areas demonstrated a constant
seaward flow of fresh water over a deeper
wedge of tidal salt water, in which most
fish were located. Trip catch, tag and
release averaged 59 stripers; however
ideal conditions allowed for as many as
150 fish to be marked in a single trip.
Juvenile fish, less than age 3 (<11">
Recapture Rates

Most ALS tagged stripers are recaptured
within three years of tagging. Thus,
near maximum possible returns have now
occurred for fish marked in '97-'00 . For
these four years, 2,298 tags have yielded
133 returns, for a 5.8% recapture rate
(Table 1), somewhat higher than the mean
of 4.5% for ALS taggers.

By the end of 2003, 252 (3.8%) of the
6,621 ALS tagged bass had been reported
recaptured. The potential to recapture any
of these tagged fish is, of course, an ongoing
situation. For example, a fish
tagged in '01 may be recaptured in 2004,
adding to the total number. Checking
Table 1, there were slightly more recaps
for fish tagged in '02, due to much larger
numbers marked that year. Conversely,
those T/R in 2003 have been out the least
amount of time, hence less chance for
recapture despite marking significant
numbers. If our recapture rate of the first
Ned Kittredge in his just-launched skill in downtown Norwich, CT, on a cold January
morning.

Next stop: striped bass.
Vol. 27, No. 1 17
three years of approx. 6% holds, we can
expect many more returns for 2001, 2002,
and 2003 tagged fish.

Recaptured fish in '97 averaged 16"
(Total Length) at tagging, and ranged
from 13" to 22". In '98, recaptured fish
averaged 18" TL at tagging, and ranged
from 13" to 29", and in '99 averaged 20"
TL at tagging, ranging from 13" to 30".
In 2,000, recaptured fish averaged 21" TL
at tagging, ranging from 13" to 30". In
2001 fish averaged 17" TL at tagging, and
ranged from 14" to 27". In 2002 fish
averaged 17" TL at tagging, and ranged in
size from 12" to 44". In 2003 fish averaged
19" TL at release and ranged in size
from 12" to 38". ( Table 2.) The progressive
increase in size of fish marked in '97-
'99 may have been due to several factors:
return of a year class for several years,
modification of fishing techniques, and
chance recapture reporting of larger fish.

Unfortunately, failure to provide valuable
recapture information by some fishermen
prevents valid reporting on length
and weight increases during at-liberty
times.

Would it surprise you to learn 48 of the
98 recaptures (49%) for the years '97-'99
came from the Thames River itself? Of
these, 11 were at liberty for over a year,
suggesting some fish return several years
in a row. At the present time, 85 fish
(34%) of all Thames stripers tagged
through 2003 have been recaptured therein,
the majority between November and
April.

Of the remaining 167 fish, 141 came
from 21 other New England rivers (See
Appendix), along with one each from the
Hudson and East River, NY. Studies published
in 1987 by Fabrizio estimated that
Hudson River origin bass make up 90% of
the Long Island Sound fishery.

Not all recaptures report the body of
water involved. If an inland municipality
was named, it was assumed the recapture
occurred in a river flowing through it, i.e.,
Derby, CT, is on the Housatonic River.
For that reason, several rivers named were
assumed to be the site of recapture though
not actually mentioned in recapture
reports.

Catch & Release Mortality

A striped bass hooking mortality study
published by Diodoti and Richards (MA
DMF) in l996 concluded that angler experience,
which was significantly correlated
to handling time, was a major factor
affecting survival of released fish. They
reported that experienced anglers helped
reduce fight times, substantially lowering
the mortality of catch and release.

Our results reflect a minimal fight time
due to small fish size and the use of short
lines, single hook lures, followed by brief
handling time, all complemented by seasonally
low water temperatures that
enhance survival rates. No doubt intense
seasonal fishing pressure along the river
significantly contributed to the elevated
recapture rate as well.

Habitat Preference

Does it surprise you to learn the bulk of
the recaptures came from New England
rivers? Juvenile fish prefer these habitats,
as estuarine environments offer tremendous
feeding opportunities. However, as
fish age and mature, habitat preferences
change, which undoubtedly contributes to
diminishing tag recaptures. Increased
swimming strength creates improved foraging
ability enabling them to make use of
deeper and stronger current waters of bays
and sounds. This habitat change reduces
the chance of recapture by shore-based
fishermen, who far outnumber those in
boats.

Therefore, it seems reasonable to
assume this may be the primary reason
why most ALS tagged fish, which are
school size (juveniles), are recaptured
within 3 years of their tagging.

Maturation leads to increased swimming
ability which changes habitat preferences.
Consequently, they become less susceptible
to recapture by shore based anglers.

Time at Liberty

Time at liberty for '97 to '99 tagged fish
ranged from as little as 4 days to 906 days.
For fish tagged in '97, the average time at
liberty was 327 days. However, the average
time at liberty was only 217 days for
fish tagged in '98, and 214 days for '99
fish. Several '97 tagged fish with near 3
year at-liberty periods contributed to this
disparity. A total of 28 trips occurred during
'97-'99, 12 during a winter-spring period
and 16 during an autumn-winter period.
Although it appears a disproportion
exists between the recapture percentage
for '98 tagged fish as compared to '97 and
'99, given the small sample number
involved, 5 additional recaptures (<1%)>
Hudson River Stocks

Various publications have reported that,
based on tagging information, Hudson
River-origin fish migrate annually in an
easterly direction. Assuming the bulk of
Thames over-winter fish have a Hudson
origin, tag-recaptures from ME, NH MA,
RI, and CT continue to confirm this
behavior.

Recaptures have come from 22 other
New England River systems including the
Merrimack River, MA, and adjacent estuarine
environs, which ranks as the primary
recapture zone. I'm reminded this estuarine
environment play a tremendously
important role in the maturation of these
stocks.

Also, to a lesser degree, other southern
New England rivers, along with coastal
ponds, are presently being utilized by
over-wintering populations, possibly the
result of competition in the Hudson
(resources in the Hudson may no longer
be able to support any more fish).

Stock Origin

Our recapture of tagged fish would help
answer the question of whether
Chesapeake or Delaware origin stocks utilize
the Thames for over-wintering.
During '97-'03, friends, clients, or myself
recaptured a total of 22 tagged stripers
from the Thames marked elsewhere.
These fish bore either U.S. Fish &
Wildlife Service (USFWS), American
Littoral Society (ALS), or Hudson River
Foundation (HRF) tags.

Two of the 6 USFWS stripers were
marked south of the New York Bight area,
one from Delaware Bay, the other from
Newport News, VA. This suggests that
few fish with a mid-Atlantic origin join
those from the Hudson to winter-over in
the Thames. In support of that premise,
we have yet to recapture any other
Thames stripers tagged in the Chesapeake
or Delaware areas.

The other 4 juvenile stripers were
tagged for the USFWS by either the New
York Department of Environmental
Conservation (NYDEC) or the
Connecticut Department of
Environmental Protection (CTDEP) in
either New York or Connecticut waters.
All ALS recaptured fish were initially
tagged north and east of New Jersey, suggesting
a Hudson-origin for these fish.

Schooling Fidelity

Our HRF tagged fish recaptures
occurred in '00, '01 and '03, all initially
tagged one or more years prior in the
lower Hudson or New York Harbor. In
December of 2001, three of the 7 HRF
tagged stripers were recaptured on three
consecutive trips to the Thames. All
recaps occurred in same area, and all were
initially marked within weeks of one
another off lower Manhattan.

Assuming these fish came from the same massive
school in the Hudson, their recapture supports
the establishment of schooling
fidelity at a young age. At the present
time HRF tag-recaptured fish outnumber
those of other tagging agencies, further
evidence suggesting most Thames overwintering
fish have a Hudson origin. Few
juvenile Hudson-origin fish are believed
to migrate south to mid-Atlantic areas,
with little evidence, if any, for their overwintering
in that region of the seaboard.

Hudson River Foundation

The Hudson River Foundation began a
Tag Recovery Program in 1984, and since
that time more than 250,000 striped bass
have been tagged. Tagging occurs chiefly
between November and April, targeting
age-1 to age-3 fish in the lower Hudson
off Manhattan. Fish are caught with use
of trawl nets by professional biologists,
and internal anchor (belly) tags are
attached prior to release. In the winter of
'01, approximately 14,000 stripers were
tagged. Annual recaptures from all tagging
years range from about 700 to 1400,
with recapture sites occurring from the
Bay of Fundy to Cape Hatteras.

Juvenile fish make treks that boggle the
mind. In fact, school-size stripers may
travel greater distances than adult fish. I
was introduced to the marvels of striper
movements decades ago ('68) when a
small striper I tagged in the Annapolis
Basin, Nova Scotia, was recaptured the
following spring in the Choptank River, a
tributary of Chesapeake Bay. I believe
this was the first record of an internationally
traveled tag-recaptured striped bass
for the ALS.

Brokenstripedness

Contrary to angler opinion, the origin of
a fish cannot be recognized by a visibly
pronounced broken stripe pattern called
"brokenstripedness". Although this morphological
aberration occurs in both wild
and hatchery reared fish, brokenstripedness
is significantly more pronounced in
hatchery reared fish. Millions of hatchery
reared fish released into both the Hudson
and Chesapeake tributaries demonstrate a
high percentage of this morphological
deformity. Studies suggest it is not genetically
based, but relates to a hatchery environment.

Recapture data indicate that stripers are
able to find their way back to favored
areas two or more years running. For
example, I've tagged bass at Block Island's
North Rip and recaptured them in the
same area a year or two later not once, but
on seven different occasions. All 12 of
my personal striper recaptures occurred in
areas in which they were initially tagged
weeks, months, or years prior.

After wintering in the Thames, the onset
of sexual maturity may drive a striped
bass to return to its birthplace in the
Hudson to spawn. Both juvenile and adult
bass winter-over in the Hudson; however
some young fish may return to the Thames
in the fall to spend another winter.

Stock Contingent

At the present time, evidence suggests
the bulk of these O-W fish are Hudson
River stock origin, and are a probable long
term contingent. How does a one year old
striper know to search out the Thames for
over-wintering? My guess is those fish
are programmed to do so (it's in the
DNA). This probably came about eons
ago due to intense competition in the
Hudson resulting from high stock abundance.

Could it be those fish that wintered
in the Thames ages ago, which provided a
sanctuary due to its deep water, close
proximity to L.I. Sound, a diurnal tidal
saltwater wedge, and high forage abundance
were so successful they passed the
"instinct" on to future generations? My
guess is yes.

Thames river over-wintering striped
bass are doing what countless generations
have done before them. No doubt the rich
forage abundance of New England rivers
centuries ago, coupled with a species biomass
greater than could be supported in
the Hudson, led to the development of this
behavior. The Thames has long suited this
behavior, serving now as a window back
into history. I feel privileged every winter-
time I visit it.

These fish are creatures of habit. They
are programmed that way because it has
contributed to success of the species.
However, we can't help but wonder about
their future. In the meantime, there will
be days spent tagging when air and water
temperatures will have me questioning my
sanity. The more we learn about striper
behavior, the more questions arise, confirming
much remains to be learned.
Rivers of Recapture
NEW YORK
East River, Hudson River
CONNECTICUT
Connecticut, Housatonic, Mystic, Niantic, Thames
RHODE ISLAND
Barrington, Pawcatuck, Pettaquamscutt, Providence,
MASSACHUSETTS
Annisquam, Bass, North, Seekonk, Westport,
Weweeantic
NEW HAMPSHIRE
Merrimack, Piscataqua
MAINE
Saco, Mousam, Scarborough, Kennebeck, Penobscot
TAGGING ACTIVITY
Year Fish Number of Trip Catch Number
T&R TRIPS AVER. RECAPTURED %
1997 377 9 42 26 6.9%
1998 560 11 51 33 5.9%
1999 582 8 73 43 7.2%
2000 779 12 65 31 4.0%
2001 1,340 22 61 45 3.0%
2002 1,855 31 60 56 3.0%
2003 1,076 18 66 18 <>

1 comment:

  1. This is a fascinating article written with scientific evidence
    or at least educated hypotheses. I am really happy to have read it. I "converted" from freshwater bass to stripers a few years back and had heard about the Thames from anglers. I am grateful the author took the time and effort to do the research and write such an informative article.

    ReplyDelete