CTFishTalk.com: The Cycle of Eelgrass and Fish Habitats - 1890-1990 IMEP 51A - Connecticut Saltwater Reports ( CT Saltwater Reports ) - A Community Built for Connecticut Fisherman.

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Continued IMEP 51A
The Cycle of Eelgrass and Fish Habitats – 1890-1990
IMEP #51 A - Habitat Information for Fishers and Fishery Area Managers Understanding Science Through History

According to Ed Wong red tide cysts were found in Mumford Cove just above “shell layers” – represented of poorly flushed nutrient rich organic sediments. This was confirmed by Malcolm Shute of the CT Health Dept a few months later (personal communication T. Visel). It was thought at the time that such poorly flushed areas (slow tidal flows) were sources of red tide cysts after heavy storms. Storms could bring them up to the surface again. Hydraulic transplanting of soft shell clams from Mumford Cove was immediately tabled.

In 1983 I informed member of the Groton Shellfish Commissioners of the presence of red tide cysts for further possible study. We looked for shell layers but could not locate any. According to local shellfish commission member accounts oystering in Mumford Cove ended in the mid 1930s. The presence of the viable cysts in Mumford was somewhat alarming – it was thought that organic acids could have destroyed the cysts coating or sulfides deep in the sediment was toxic to them as well (during the Mumford Cove Shellfishing survey sulfur smells were often quite strong). Many of the soft shell clams sampled shells at two feet deep on the exposed bars crumbled easily from acidic erosion (T. Visel observations). No oyster shell layers were observed in any the test sites I examined in 1981 or UCONN Sea Grant surveys 1983 that followed (pipe penetration tests).

Environmental History – Mumford Cove

Mumford cove lies within the Town of Groton, CT and is the remains of drowned lagoon. Weak ebb flows cuts a storm driven still, between a large barrier spit system south east at Groton Long Point – a smaller barrier spit in on the western cove. It was mentioned that dredging projects followed the 1938 Hurricane. The cove has an open exchange to the Long Island Sound but is susceptible to storm events according to local residents the 1938 Hurricane drove a wedge of sand deep into the cove. It has never been a deep water anchorage but a salt pond was dredged (Ford Canal – Venetian Harbor) part of the Groton Long Point community and a second canal north part of the Mumford Cove Association mid point in the cove east side. Many reports mention first dredging projects occurred in the mid 1950s. The cove is surrounded by glacial till (Bushy Point State Park to the east), salt marsh to the north, and a mixture of residential communities on its east shore. Mumford Cove and Groton Long point communities use Mumford Cove for largely recreational purposes.

The Morphology of the Cove was well defined by a Wesleyan University study and is in the attached pages.

Fisheries History –

1870s – Mumford Cove as many eastern CT coves were known to have had mixtures of estuarine shell/sandy habitats during storm and cold periods. Local reports mention eel spearing (eels prefer poorly flushed sulfur organics) that supported eel fisheries in winter times. Local historical societies in the region have numerous accounts of eastern CT eel/spear fisheries.

The mid Atlantic – New England historical fisheries are filled with accounts of winter ice spear fisheries for eels. And is most likely the reason why eelgrass got its name – the Sapropel eelgrass crust in which eels would hibernate or hide during the day protected from the sulfide seeps (smells) that kept large predators away – such as striped bass. In a winter fishery holes would be cut into the ice on such salt ponds and coves over shallow deposits of “eelgrass.” Spears with hooked tips (not straight) were often called eel gigs (Lee 1980). The best spear fisheries were areas of soft organics deep muck – Sapropel – some coves such as Alewife Cove in CT were named for the fisheries they once supported and a century ago the most productive eel areas were often called eel river or eel pond for example. These areas had the soft muck that eels (and terrapins) sought out to hibernate and in periods of warmth – blue crabs as well. In the historical literature eel spear fisheries mention blue crabs mixing in at times (attempts were made to market speared crabs in New Jersey without success). Both eels fisheries and blue crab landings (overlap) especially in the New York, Long Island fisheries history. The open more energy prone eastern Long Island Sound had at times firm bottoms at times soft and Ruppia (Duck weed) from core studies.

The Groton Connecticut region in the 1880s also supported a large winter flounder fyke net fishery – (Smith US Fish Commission 1889) – winter flounder would return to these coves in spawn in February March.

This area of Connecticut was the center of a growing fyke net fishery for winter flounder and the concentration of fykes in this area was among the most important in the country. H. M. Smith writes in a US Fish Commission Bulletin section on The Fyke Nets and Fyke Net Fisheries of the United States “As already shown the fyke net fishery of Connecticut is more important than that of any other state.” The placement of pounds and fykes also is concentrated in eastern CT – State of Connecticut 4th Biennial – Report of the State Commissioners of Fisheries and 1901-1902 Hartford 1902) locates 60 registered trap fyke net sites at the mouths of Eastern CT coves pg 36 – 42. The center of this fyke net fishery was Groton.

Hugh Smiths article about this eastern CT winter flounder fishery is attached but the largest number of fykes were between Stonington and New London (1889) Eastern CT is a high energy zone and prone to the greatest habitat reversals – as evidenced by historic shell layers in these eastern coves. In cooler high energy periods firm bottoms and bivalve shell was prevalent in warm and low energy periods – Sapropel (sulfuric ooze) and submerged aquatic vegetation. Coastal processes continue to shape the cove after storms, change barrier spits or move organic deposits.

In the late 1980s winter flounder fishers reported distinct habitat changes in many of these eastern CT coves (hard firm bottoms to soft)). Many accounts linked the presence of railway causeways as the source of reduced energy and increase in organic matter behind which on August nights shed sulfur smells – the marsh gas “stinks.” In talking to Mumford Cove residents who spoke to us during the shellfish survey in 1981 mentioned at times horrific smells from the flats – now the center of Mumford Cove (many residents asked if we could do anything about the smells).

In 1991 in response to winter flounder concerns in eastern CT the Dept of Environmental Protection (now DEEP) contracted with Wesleyan University Dr. Peter Paddon to core eastern CT coves looking for shell layers and information on these organic deposits and sedimentation rates. In the grant award CWF 266-R 7/1/91 to 6/30/93 – Post glacial stratigraphy and rates of sediment accumulation in three small Connecticut coves. Dr. Peter Paddon includes a habitat history for Mumford Cove which is sill relevant today. See attached pages.

History of Oyster Culture – Mumford Cove

J. W. Collins notes on the oyster industry of CT table 52 – lists both Quiambaug and Mumford Cove as producing 2 to 4 thousand bushels/year of oysters mostly from bedding stock. Quiambaug Cove and Poquonnock River west was extensively leased for oyster culture but no such records were obtained for Mumford Cove. The oyster shell layers in Mumford Cove mentioned by Wong (1981) could have been previous core tests that hit these 1880s beds. Mumford Cove was planted by several CT oyster companies including the New Haven based McNeil Oyster company. George McNeil in the 1980s recounted visiting eastern coves with seed oysters in the early 1930s about the period that oystering in eastern coves declined. The location of these aquaculture beds were thought to be in the interior cove center. According to local accounts the 1938 Hurricane did much to alter the bottom topography and ended oystering altogether (various comments from Groton Shellfishers 1980s). Although, Mumford Cove was included in the core study the cove center was not cored only the shores (one core MC-2 near the marsh edge) but black organic deposits extensively mapped – called black mud facies however those organic deposits were not cored as well.
-From the Patton Study-

Black mud facies is described by B.W. Flemming A. Bartoloma (2009) as “sulphurous – grey – black mud facies” pg 176. Black mud facies is a geology term but biologists know it as sulfuric ooze, sulfate acidic soil or Sapropel. Although no center Mumford Cove cores were examined in this study – one core was described at the northern edge extreme upper part of the cove as core as core M-C-2 (pg 23). “The upper 4 meters of this core is black mud that is bound my plant roots” showing distinct layers of black mud and dense ruppia roots. (Cores of the Poquonnock River in a later study grant #CWF-310-R 8/26/93 to 8/31/01 has multiple cores showing distinct shell layers). The report mapped the black mud facies and the thickest deposits were in the center of the cove shown on Dr. Patton describes the Black mud facies as follows, pg 25, it is also the deposit mentioned by the 1981 reviews as harboring red tide cysts.

“Black Mud Facies – All of the cores recovered from the open water substrate of the coves contain gray to black mud. The mud is largely structureless but does contain thin sand layers, particularly in cores taken near the mouth of the coves, for example core QC-3 (Fig. 13). The sand layers may represent individual storm events but it was not possible to date them or to correlate them for core to core. These are also occasional mollusk shells and the mud is often bound by the roots of marine grasses, probably Ruppia, for example the 4-m thick mud unit in core MC-2 (Fig. 14). The mud unit begins at the sediment water interface and can be up to 6m thick” page 17.

Attachment # 1

Wesleyan University CWF 266-R Post Glacial Stratigraphy and
Rates of Sediment Accumulating in three small Connecticut Coves
Results
Cove Morphology – pg 8 Patton Study

“Bathymetric maps constructed from surveys conducted in 1991 were compared to the modern charts and to the oldest recorded bathymetric data for each cove. The results for each cove are described below, more detail on each cove is provided by McLoughlin (1992).

Mumford Cove

Detailed bathymetric data for Mumford Cove dates to 1882 (Fig. 3). This bathymetric survey indicates that most of the cove was 2 to 3 feet deep, with the exception of one location, approximately halfway up the cove, that was 5.5 feet deep. Subsequent bathymetric maps published in 1887 and 1932 show nearly identical bathymetry, the 1932 chart indicates a central channel that ranges from 4.5 to 5.5 feet deep (Fig. 4). The modern chart shows the channel, dredged in 1950 and again in 1982, which deepened the natural channel between 7 and 9 feet and extended the channel to the head of the cove. Our 1991 survey does not differ from the 1982 chart (Fig. 5). The bathymetric record shows that there has been little change to the depth of the cove over the past 100 years with the exception of the dredged navigation channel.

The historic charts do indicate changes to the western shoreline. An 1847 chart of Fishers Island Sound shows the existence of sand spilt built eastward into the cove from the rocky headland of Bluff Point. By 1882, this spit had been eroded and in its place was a small marsh island that was still present in 1934. In the past 50 years a new spit has built eastward from Bluff Point and has prograded across the position of the marsh island. At low tide, salt marsh peat crops out in the swash zone of the spit, revealing the position of the now buried island. Aerial photographs of the cove also show that the mouth of Mumford Cove is a broad shoal consisting of a complex of sand bars, similar to swash bars at the entrance to coastal inlets. This shoal limits the water depth at the mouth of the cove which, in the absence of the dredged channel, would be approximately 2 feet deep at low water.”

It is evident from US Fish Commission reports (Smith 1889) that area habitats were once conducive to winter flounder and Collins (1880) to oyster culture. The sediment/Sapropel conditions surveyed in Mumford Core no longer provided hard bottom habitats for oyster culture. No relic or surviving oysters were found in an University of CT Sea Grant shellfish survey in 1983 (Visel, Holloway), nor a 1985 review of oyster setting. (Test shell oyster spat bays were set along the main channel in the harbor at Groton Long Point – no set was recorded).

Red Tide Cysts were found in 1981 and reported by Maranda et al 1985 (Estuarine, Coastal and Shelf Science 21 pages 401-410) to be in Mumford Cove Strain (Isolates #CIC-2) and by Anderson et al in 1982 (Estuarine, Coastal and Shelf Science 14-447 to 458 and the CT Health Dept Malcolm Shute in June 1985 (The Day Newspaper June 21, 1985) “State Health Officials Urge lifting Groton Shellfishing Plan” as levels had dropped to 44 micrograms of toxin for 100 grams of shellfish meat – below the recommended level of 80 micrograms. A red tide bloom was reported in Palmer Cove east of Mumford Cove in 1983. The prohibition (1981) upon hydraulics dredging for shellfish in Mumford Cove continues by the CT Dept of Agriculture Aquaculture Division which is also attached (under abstract phyto plankton monitoring.) The presence of red tide cysts could be a valuable tool in climate change studies, we have in Mumford Cove one of the largest accumulations of Sapropel – boxed by oyster shell habitats of the last century and reports by US Fish Commission reports that includes Mumford by name and date.

The location and depths of Sapropel in Mumford cove raises the question of eelgrass succession that it being more tolerant of sulfides than Ruppia (Widgeon grass or duck weed) – hunters tell me that ducks ate this SAV along the coast years ago. The presence of Ruppia in the cores from the Mumford Cove, Patton study also indicates that at times Mumford Cove may have had species reversals connected to habitat – governed by climate conditions. Habitat types do change and Sapropel eelgrass types have been linked to sulfide purging and huge ammonia generation. These two toxins may influence eelgrass growths which lock these deposits in place – with viable red tide cysts released by storms. Researchers are examining these events as they relate to fish and shellfish abundance and the successional attributes of eelgrass itself. The most important aspect might be the level of pore water sulfides in eelgrass in Mumford Cove.

In 1987 the sewage plant outfall discharges was removed from the head of Mumford Cove following lengthy legal negotiations. Summers continued to warm to excessive heat and sulfide ammonia levels most likely increased. Eelgrass returned to the cove but since Irene and Sandy the cove morphology may have also changed as they have in the past. Would Mumford Cove support oyster culture today – I doubt it – a return to the 1870s when cold and storms dominated our climate perhaps that is when Long Island Sounds cold and stormy period gave rise to the Sounds nickname by maritime interests. During that stain filled and bitters cold climate period they called Long Island Sound – “The Devils Belt.”

After Hurricane Gloria and removal of the 1945 sewer outfall in 1987, eelgrass not duckweed became abundant in Mumford Cove. The question of the removal of 3.5 million gallons per day of aqueous human nitrogen upon the nutrient residence time in Mumford Cove opens the question of two nitrogen sulfur cycles- the short cycle of readily available plant nutrients dissolved in seawater (oxygen-human) or the second cycle a much longer cycle – sulfate digestion of organic matter (leaves) by sulfur reducing bacteria (sulfur/Sapropel) in heat and low energy conditions (black facies). The Gary Park selvage plant discharged up to 3 million gallons (or more) of treated sewage per day influencing the salinity flowing from Fort Hill Brook. The Mumford Cove watershed is rather limited and therefore cove salinities subject to tides now more than runoff. The presence of nitrate is a buffer to the sulfate/sulfur cycle and that also impacts sulfate reduction.

Ammonia levels and sulfide purging are two important indicators for the cycle of eelgrass. Dr. Feng (1983) as I recall had questions about the nutrient loads into Mumford Cove, and one of the questions of habitat quality related to the presence of the red tide cysts. That caused a larger questions of long term habitat stability and habitat history of Mumford Cove-itself how did the red tide cysts get so deep and where were the missing oyster beds?

The cycle of eelgrass as experienced during The Great Heat (1880-1920) allowed the expansion of eelgrass in a very warm and low energy period was related to its tolerance of sulfides and high salinity/low energy. That would put the cycle of eelgrass directly dependent upon cyclic conditions- not us.

-15-
G. THE FYKE NETS AND FYKE-NET FISHERIES OF THE UNITED STATES,
WITH NOTES ON THE FYKE NETS OF OTHER COUNTRIES.

BY HUGH M. SMITH, M.D.
CONNECTICUT
As already shown, the fyke-net fishery of Connecticut is more important than that of any other New England State. Compared with 1880, the fishery seems to have about doubled in extent, judging by the number of nets used, although there are no data for 1880 on which to base a comparison of the catch and stock. The average value of the nets, however, seems to have decreased. In 1880, the number of fykes reported for the State was 255, valued at $2,480; in 1880, the number was 440, worth $2,230.
Fyke-net fishing is carried on along most parts of the coast of this State. All the prominent towns have more or less fishing of this kind. The largest number of nets is found in Stonington, Quiambog, Mystic, Noank, and New London. The distribution of the fykes in 1889 was as follows:

Fish now taken in the fyke nets of Connecticut are principally flounders, frostfish, tautog, menhaden, and striped bass. In a few places terrapin are taken, and in Stratford these are much more valuable than the remaining part of the catch. In 1880 the species reported to be caught in fyke nets were sea bass, cod, bluefish, eels, weakfish, flounders, herring, shad, and occasionally sturgeon. At Mystic the nets are set about February 1 and taken up about March 31: they are again set about October 1 and remain down until December 31. Flatfish and frostfish are taken. At Noank, the nets are fished from the first of February to the last of April, and
319
FYKE NETS AND FYKE-NET FISHERIES

from the first of October to the middle of December. The principal fishing, however, is done in the spring. The nets are placed in water 6 to 15 feet deep. In Groton the fykes are operated at the mouths of the rivers during June and July, and within the rivers during the rest of the year; flounders and frostfish are secured. The nearly 140,000 pounds of flounders, frostfish, and tautog, valued at $2,550, were obtained 1889. Severn nets at Branford were fished for menhaden; about 100,000 fish were taken in the year named.
The fyke net fishery of Connecticut in 1889 resulted in the capture of 455,250 pounds of fish, valued at $8,759, and 1,019 terrapin, worth $1,280. The quantities of the different fishes were as follows:
Products of the fyke-net fishery of Connecticut.

STATE OF CONNECTICUT DEPARTMENT OF AGRICULTURE BUREAU OF AQUACULTURE & LABORATORY
Protocol for Hazardous Algal Blooms/Marine Biotoxin Events State of Connecticut
Department of Agriculture Bureau of Aquaculture

Effective Date: 02/23/11

INTRODUCTION TO BIOTOXINS:

Due to their filter feeding nature, shellfish have the ability to concentrate toxigenic dinoflagellates from the water column in their viscera when these dinoflagellates are present in shellfish growing waters. The toxins produced by these dinoflagellates can cause illness and death in humans. These toxins are not normally destroyed by cooking or processing and cannot be detected by taste. Since the dinoflagellates are naturally occurring, their presence in the water column or traces of their toxin in shellfish meat does not necessarily constitute a health risk. To protect the consumer, the Authority must evaluate the concentration of toxin present in the shellfish or the dinoflagellate concentration in the water column against the levels established in the NSSP Model Ordinance to determine what action, if any, should be taken.

There are three types of shellfish poisonings which are specifically addressed in the NSSP Model Ordinance relevant to the waters of Connecticut: paralytic shellfish poisoning (PSP), neurotoxic shellfish poisoning (NSP) and amnesic shellfish poisoning (ASP), also known as domoic acid poisoning. All three are dangerous toxins, and PSP and ASP can cause death at sufficiently high concentrations. In addition, ASP can cause lasting neurological damage. PSP is caused by dinoflagellates of the genus Alexandrium (formerly Gonyaulax). NSP is caused by brevetoxins produced by the dinoflagellates of the genus Karenia (formerly Gymnodinium). Both of these dinoflagellates can produce "red tides", i.e. discolorations of seawater caused by blooms of the algae. Toxic blooms of these dinoflagellates can occur unexpectedly or follow predictable patterns. Historically, Alexandrium blooms have occurred between April and October along the Pacific coasts from Alaska to California and in the Northeast from the Canadian Provinces to Long Island Sound; but these patterns may be changing. The blooms generally last only a few weeks and most shellfish (with the exception of clams which retain the toxin for longer periods) clear themselves rapidly of the toxin once the bloom dissipates.

Phytoplankton and shellfish monitoring program:

Mussels are collected from bags located in Palmer and Mumford Cove in Groton and brought to DA/BA laboratory for processing. Additionally, the use of a hydraulic dredge is not permitted in Mumford Cove in order to prevent the re-suspension of cysts of
HAB causing organisms. In Palmer Cove all operations must cease by April 15th before the water temperature rises above 50 F.