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-The internal anatomy and part of the shell of the northern quahog (from Brown, Selected Invertebrate Types, 1950).
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The northern quahog, Mercenaria mercenaria, ranges along the Atlantic Coast of North America from the Canadian Maritimes to Florida, while the southern quahog, M. campechiensis, ranges mostly from Florida to southern Mexico. The northern quahog was fished by native North Americans during prehistoric periods. They used the meats as food and the shel...
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... tides are also present in Bar- negat Bay, Little Egg Harbor, and Great Bay, N.J. (Mahoney 9 ) (Fig. 14). Similarly to Great South Bay, the meats of qua- hogs become thin and the same tissues become dark gray during dense blooms. Figure 13.-Quahog meat on left has normal plumpness and pale color, while quahog meat on right is thin and dark gray after being affected by "brown tides." The "black" quahogs in both states are more diffi cult ...
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... is most commonly prac- ticed on intertidal fl ats within the bays and estuaries of coastal Virginia and North Carolina. Fishermen look for the quahog's siphon holes and fecal pellets and then use a pick (Fig. 40) or rake for collection. Each harvester can collect 2-4 bu of quahogs during a low ...
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... in North Carolina and South Carolina use pea diggers, 4-tined rakes (Fig. 41), to harvest quahogs on intertidal fl ats which have considerable quantities of shells or stones. They dig in soft areas around the objects to fi nd the ...
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... in Nova Scotia in 1721 ( de Charlevoix, 1744). Quahog hand tongs differ from oyster hand tongs slightly in having more steeply angled teeth, allowing penetra- tion into sediments to grasp quahogs, and the teeth are spaced about 35 mm apart instead of 50 mm apart as in oyster tongs. They require greater effort from the fi sherman than oyster tongs (Fig. 42). Tongs continue to be used in many localities from the Canadian Maritimes to Florida (Fig. 43, 44); their use is limited to depths less than 3.7 ...
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... powered patent tongs remain large and heavy (Fig. 45), most boats now operate with just one person due to their mechanical effi ciency. Boats with two patent tongs have one on each side and two people. When currents run too fast, fi shermen drag a weight along the bottom to slow the boat ...
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... seed fork is similar to a short- handled manure fork, but the teeth are closer together (31-34 mm apart) (Fig. 46). This fork works well in soft sub- strates (Ashley 20 ). The quahoger pushes it into the substrate at a slight angle and moves the handle up and down as the fork is moved forward just below the surface. He lifts the rake through the substrate and then up to his waist and removes the qua- hogs off its ...
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... long-handled bull rake originated in Raritan Bay, N.Y. and N.J., in about 1863 (Leonard, 1923) (Fig. 47). It has also been called a "Keyport" rake and a "Shinnecock" rake. The fi rst rakes were about 75 cm wide with about 30 curved metal teeth, and they were used with wooden handles. Before their development, Raritan Bay fi shermen knew little about quahog abundances in bottoms beyond wading depths. Bull rakes were used consistently ...
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... first bull rakes were made by blacksmiths in Keyport, N.J. The fol- lowing description of how the rakes and handles were made is from MacKenzie (1992a:150-152) (Fig. ...
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... about 1960, fishermen and blacksmiths have made progressive changes in the design of bull rakes. The latest designs were based on the shape of the basket rake (Fig. 49). Some fi sh- ermen call the new design a "bubble" rake, owing to its shape (Fig. 50). The rake head usually is about 65 cm wide, but some fi shermen have models as wide as 1.5 m for harvesting in soft mud-like sediments. The rake is used with an alu- minum handle that has more fl exibility, less weight, and is stronger than wooden ...
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... wide as 1.5 m for harvesting in soft mud-like sediments. The rake is used with an alu- minum handle that has more fl exibility, less weight, and is stronger than wooden handles (Fig. 51, 52, 53). The handle comes in 3.7-m sections. Its handle length is adjusted by moving the sec- tions inside one another, their positions being held by hose clamps (Fig. 54). The cross heads which the diggers hold are 36 cm wide. Those used in Raritan Bay are straight, whereas Rhode Islanders use slightly bent cross heads that are more comfortable to hold (Fig. 55). Bubble rakes far out-harvest the original Key- port bull rakes; one fi sherman (Harry 21 ) estimates it harvests about twice as many quahogs ...
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The northern quahog, Mercenaria mercenaria, ranges along the Atlantic Coast of North America from the Canadian Maritimes to Florida, while the southern quahog, M. campechiensis, ranges mostly from Florida to southern Mexico. The northern quahog was fished by native North Americans during prehistoric periods. They used the meats as food and the shel...
Citations
... shing, watercraft, and navigation (Patton 2014). Shantok could thus also be conceptualized as an "animated shellscape" where marine mollusks act as both sources of sustenance and agents of diplomacy. The site was ideally situated, on a river that opened into the ocean with the proper mix of salt and freshwater that whelk and quahog require to grow (MacKenzie Jr. et. al 2002). This evidence alone bespeaks Indigenous ecological knowledges, rooted in an intimate familiarity with the seasons and spaces for harvesting local flora, fauna, and marine mollusks. All of the activities conducted at Shantok-shellfish harvesting, wampum-making, feasting, pottery-making, diplomacy, ceremonial activities, burials, etc.-re ...
... Navalur lake hade high levels of potassium, sulphate, nitrate and chloride but very less dissolved oxygen which is not favorable for algal growth, Dissolved oxygen is used for photosynthesis and respiration .the solubility of oxygen decreases with increasing temperature (Mackenzie et al., 2002). Nuggekeri and Unkal Lake had high levels of nutrients along with Good amount of dissolved oxygen, conductivity, calcium, Sulphates and low nitrate level was detected as it is accumulated by algae, such factors are most favorable for algal growth and proliferation. ...
The world today is facing two major problems, of oil crisis and global warming; microalgae have been focused as living organisms that have high potential in solving both these problems by producing bio fuels and carbon sequestration. Aim of the study is to estimate physical and chemical parameters and to determine the algal diversity in ten lakes in the district of Hubli and Dharwad. Lipid content of algae will be analyzed. Physico-chemical analysis of lakes was done to check eutrophication of lakes by estimating the amount of physical factors like pH, turbidity, temperature, electrical conductivity and chemical parameters like alkalinity, calcium, magnesium, total hardness, potassium, sodium, phosphates, chloride, sulphate, nitrates, D.O, C.O.D, B.O.D present, which indeed serve as nutrients for the growth and proliferation of algal species. In this investigation, two lakes were found to be entropic and algal diversity present in all ten lakes were determined. About 20 different algal species were isolated and studied for lipid content. Out of this four species showed high potential for biofuel production.
... The northern hard clam or northern quahog, Mercenaria mercenaria (Linnaeus, 1758), hereafter hard clam, is a marine bivalve inhabiting soft substrates of mud, sand, and shell fragments in coastal lagoons and estuaries from the Gulf of St. Lawrence, Canada, through the northern Gulf of Mexico (Mackenzie et al., 2002). ...
... Hard clams have high fecundity and broadcast spawn from spring through fall depending on latitude, with timing and the length of the spawning season affected by temperature and food availability (Eversole, 2001;Roegner & Mann, 1990). The pelagic larval duration (PLD) is temperature dependent, lasting 18-24 days in 18°C water and 7-14 days in 30°C water, until the clams reach the proper size and development for metamorphosis (Mackenzie et al., 2002). Juveniles and adults are considered to have a sedentary life in the benthos due to their limited post-metamorphosis mobility, so the interactions among PLD, hydrodynamics, geography, and other physical factors are thought to shape genetic connectivity (Cowen & Sponaugle, 2009). ...
Abstract Aquaculture is growing rapidly worldwide, and sustainability is dependent on an understanding of current genetic variation and levels of connectivity among populations. Genetic data are essential to mitigate the genetic and ecological impacts of aquaculture on wild populations and guard against unintended human‐induced loss of intraspecific diversity in aquacultured lines. Impacts of disregarding genetics can include loss of diversity within and between populations and disruption of local adaptation patterns, which can lead to a decrease in fitness. The northern hard clam, Mercenaria mercenaria (Linnaeus, 1758), is an economically valuable aquaculture species along the North American Atlantic and Gulf coasts. Hard clams have a pelagic larval phase that allows for dispersal, but the level of genetic connectivity among geographic areas is not well understood. To better inform the establishment of site‐appropriate aquaculture brood stocks, this study used DArTseq™ genotyping by sequencing to characterize the genetic stock structure of wild clams sampled along the east coast of North America and document genetic diversity within populations. Samples were collected from 15 locations from Prince Edward Island, Canada, to South Carolina, USA. Stringent data filtering resulted in 4960 single nucleotide polymorphisms from 448 individuals. Five genetic breaks separating six genetically distinct populations were identified: Canada, Maine, Massachusetts, Mid‐Atlantic, Chesapeake Bay, and the Carolinas (FST 0.003–0.046; p
... Thus, declining purple wampum ratios might be explained by intensive harvesting of younger quahogs. The lifespan of M. mercenaria can range up to 40 years, but in the 1800s, the new dish called "littlenecks" emerged from quahog harvesting between the ages of two and three years old (MacKenzie et al. 2002). The thick purple lip of shells ideal for wampum production does not develop until later in the organism's life-course. ...
From at least 1750 until 1900, Euro-American settlers of New York and New Jersey appropriated the production of Indigenous North American shell beads, namely wampum. Excavations at the David Campbell House in northeastern New Jersey yielded deposits of worked shell coterminous with household assemblages dating from 1810 to 1850. Artifact analyses combined with merchant ledger manuscripts reveal the chaîne opératoire of settler beadmaking from 1770 to 1900, including temporalities of production, waste, and racial and gendered labor dynamics in transition to factory production. Conclusions warrant greater archaeological attention to the relationship between capitalist industrialization, settler-colonial dispossession, and Indigenous resistance.
... Drilled Mercenaria valves collected from a natural setting, the beach at Sandy Hook, were even smaller (Fig. 3A,B). Under natural settings, Euspira do not feed on Mercenaria >50 mm A-P length (MacKenzie 1977, Kitchell et al. 1981, Bricelj 1992, MacKenzie et al. 2002, Sandy Hook sample this study), when other prey are present. By restricting our analysis to the largest prey, the list of potential drilling predators was shortened, relative to the number of potential predators of small prey, thus simplifying the analysis. ...
Drillholes made by naticid and muricid gastropods are frequently used in evolutionary and ecological studies because they provide direct, preservable evidence of predation. The muricid
Ecphora
is common in many Neogene Atlantic Coastal Plain assemblages in the United States, but is frequently ignored in studies of naticid predation. We used a combination of Pliocene fossil, modern beach, and experimentally derived samples to evaluate the hypothesis that
Ecphora
was an important source of drillholes in infaunal bivalve prey shared with naticids. We focused on the large, thick-shelled venerid,
Mercenaria,
which is commonly drilled by naticids today. Laboratory experiments, modern beach samples, and the published literature confirm that naticids preferentially drill near the umbo (significant clumping of holes), show a significant correlation between prey size and predator size (estimated by outer borehole diameter), and prefer
Mercenaria
<50 mm antero-posterior width when other prey are present. Fossil samples containing
Ecphora
(with or without other large muricids) show no drillhole site stereotypy (no significant clumping, greater variability in placement), no significant predator: prey size correlation, drilled prey shells larger than the largest modern naticids could produce in an experimental setting, and drillholes larger in diameter than those estimated for the largest Pliocene naticids, thus supporting our hypothesis. Substantial overlap in the placement of holes drilled by naticids and muricids, however, made identifying predators from drillhole position problematic. The lack of overlapping ranges of prey shell thickness between fossil and other samples precluded the use of drillhole morphology to establish predator identity (e.g., ratio of inner borehole diameter to outer borehole diameter, drillhole angle). Whereas the difficulty in determining predator identity from drillholes limits the types of analyses that can be reliably performed in mixed-predator assemblages, recognizing
Ecphora
as a prominent drilling predator creates the opportunity to investigate previously unrecognized questions.
... Embora se saiba que antes da chegada do gancho na RESEX, o aparelho já era utilizado no Rio de Janeiro (Ribas, 2014), não há registros sobre a origem exata do equipamento no Brasil, que se assemelha a outros petrechos empregados em pescarias de bivalves endobentônicos costeiros ao redor do mundo, como a dos veneróideos Cerastoderma edule na costa portuguesa (Gaspar et al., 2003), e de Mercenaria spp. na costa leste estadunidense (MacKenzie Jr. et al., 1999). No Brasil, o gancho parece ser empregado exclusivamente na RE-SEX do Pirajubaé. ...
A Reserva Extrativista Marinha do Pirajubaé (RESEX) situa-se na zona urbana de Florianópolis, capital do
estado de Santa Catarina – Brasil, e tem no bivalve conhecido como berbigão (Anomalocardia brasiliana) o
seu principal recurso pesqueiro. Por meio de 100 acompanhamentos diários da atividade extrativista realizados em 2005, este trabalho descreve a estrutura e a dinâmica da pesca do berbigão, apresentando o histórico de seu manejo. A captura foi realizada com a draga de mão, conhecida como “gancho”, por 22 homens e quatro mulheres, predominantemente no período matutino e sob lâminas d’água entre 20 e 50 cm. Em média, cada extrativista varreu 469,2 m2 e capturou 270,5 kg de berbigões vivos por dia de pesca, totalizando 888,6 t produzidas na RESEX em 2005. Mais de 97% dos indivíduos capturados superaram o tamanho mínimo legalmente estabelecido (20 mm de comprimento). Entretanto reduções expressivas nos comprimentos e na abundância do recurso ocorreram ao longo do tempo. A maior parte da captura foi comercializada com poucos compradores e na forma cozida e “desconchada”. As medidas de manejo atuais incluem limitações no número de extrativistas e no número de dias e horários de pesca/semana, distância mínima entre as barras de ferro do gancho, tamanho mínimo de captura, rotação espaço-temporal das áreas de pesca e o informe estatístico da produção. Apesar do grande volume de conhecimento científico e tradicional acumulado na área, e das medidas de manejo em vigor, construídas participativamente, a sustentabilidade da explotação do berbigão e da RESEX como um todo é constantemente ameaçada por fortes pressões de ordem administrativa, social, econômica, ambiental e burocrática. Neutralizar essas ameaças representa um dos principais desafios a serem enfrentados nessa importante unidade de conservação federal do Sul do Brasil.
... All the available shellfish beds in the state (28,328 ha) are currently under lease with income from production rising from US$3.5 million in 1990 (146,250 bags) In Connecticut, towed hydraulic dredges are used to harvest hard clams. These dredges use high-pressure water jets to loosen the sediments and dislodged clams are collected in mesh bags as the dredge bar passes over the fluidized bottom (MacKenzie et al. 2002a). Water pressure is sufficient to remove clams without shell damage (Jolley 1972). ...
... Water pressure is sufficient to remove clams without shell damage (Jolley 1972). Because hard clams grow slowly, cultivated shellfish beds are dredged every 3-5 years to allow clams to reach harvestable sizes (MacKenzie et al. 2002a(MacKenzie et al. , 2002b. The use of towed fishing gear elicits some concerns because of potential damage to non-target benthic organisms, chronic effects to diversity in the dredge track, and potential biogeochemical changes in the sediments (Levy 1998;Watling and Norse 1998;Watling 2005). ...
A before-after-control-impact (BACI) experiment was conducted to examine the effects of hydraulic clam dredging on sediment biogeochemistry of a leased shellfish bed of Mercenaria mercenaria, northern quahog, over the course of an entire growing season. Six study plots (0.67 ha each), three dredged and three not dredged, off of Milford, Connecticut, in Long Island Sound, were sampled from May to October 2009 for porewater fluxes of total ammonia, oxygen, and hydrogen. Particulate samples were also analyzed for grain size, total nitrogen, total carbon, total sulfur, and organic carbon. Statistical analysis indicated no significant difference between dredged and not dredged sites. Grain size and oxygen flux explained 22% of the variation in the total benthic species assemblages; grain size and either total carbon or organic nitrogen explained 18% of the variation in molluscan abundance. Our study demonstrates that one-time hydraulic shellfish harvesting had minor effects on the sediment chemistry of a leased clam bed.
... Hard clams, burrowed within sediments, are typically harvested with towed hydraulic dredges, where a pump on the fishing vessel sends water through a hose to a manifold on the dredge. High pressure jets loosen sediment, and dislodged clams are collected in a chain mesh bag as the dredge bar passes through the fluidized sediment (MacKenzie et al. 2002). Water pressure must be sufficient to loosen sediments, but not so great as to damage clams (Jolley 1972). ...
... Designing experiments to assess the ef fects of hydrau lic dredging on the marine benthos is challenging, since the goal is to measure change in a fluctuating envi ronment. Before-after-control-impact (BACI) studies are often used to distinguish naturally occurring environmental variability from changes induced by manmade activities (Dame et al. 2000, 2002, Hewitt et al. 2001 and have been applied to study fishing effects on benthic communities (Mercaldo-Allen & Goldberg 2011, Stokesbury et al. 2011). Preliminary 'before' sampling in BACI-style ex periments pro vides a baseline for assessment of dredging effects and identification of environ mental or biological factors that could confound analysis (Kaiser 2005). ...
A before-after-control-impact (BACI)-style experimental design was used to assess the short-term effects of hydraulic clam dredging on the benthic community of a leased shellfish bed along the Connecticut coast of Long Island Sound, where hard clams Mercenaria mercenaria are cultivated. Three replicate samples were collected from 6 plots (0.67 ha each) on a weekly basis from May through October 2009. Dredging was conducted in early July in 3 of the 6 plots, while 3 control plots were not dredged. Pairwise comparisons and multivariate analyses of main effects and interactions indicated that ecological indices did not differ significantly between dredged and not dredged plots, although sample date and plot both had significant effects. Assemblages of individual species were associated with specific sediment types found within the clam bed. Natural seasonal settlement patterns and sediment grain size had a greater influence on the benthic community than discrete hydraulic clam dredging.
... Mercenaria campechiensis inhabits sandy or muddy sand sediment in the intertidal to subtidal zone, and is especially abundant in bays and estuaries (Kraeuter and Castagna, 2001). This species occurs in the warm-to cold-temperate biogeographic provinces from south Florida to southern New Jersey along the Atlantic coast of the United States and along the Gulf of Mexico coast (Arnold et al., 1998; MacKenzie et al., 2002; Merrill and Ropes, 1967). Optimal water temperature and salinity for growth ranges from 15 to 25°C and 20 to 30 psu (practical salinity units), respectively, and growth rate slows below 9°C and above 31°C or below 17 psu (Ansell, 1968; Kraeuter and Castagna, 2001). ...
Archaeological evidence from coastal southwest Florida suggests this region and its local inhabitants (the Calusa) were affected by drought and cooling during the Vandal Minimum climate episode (ad 500–800). To test this hypothesis, we reconstructed seasonal-scale climate conditions using stable oxygen and carbon isotope ratios (δ18O and δ13C) preserved in Ariopsis felis otoliths and Mercenaria campechiensis shells. Comparing δ18O records from both species distinguishes between cool versus warm and wet versus dry conditions. δ18O values from four otoliths indicate cooling of winter temperatures occurred in the early Vandal Minimum (ad 500–600) and late half of the middle Vandal Minimum (ad 650–700). Persistent dry summers punctuated by occasional years with wet summers throughout the Vandal Minimum were detected from δ18O values of eight archaeological shells. Our climate reconstructions are in good agreement with archaeological observations and with the cool and dry conditions documented in Europe.
... The northern quahog, or hard clam, Mercenaria mercenaria, ranges from Prince Edward Island and the southern Gulf of St. Lawrence, Canada, to the central coast of eastern Florida (Dillon & Manzi 1987, MacKenzie et al. 2002, LeBlanc et al. 2005). Ingersoll (1887) described a discontinuity in the distribution of hard clams between New Brunswick and the Maine/ New Hampshire border, except in a few sheltered bays in southern Maine. ...
The easternmost commercial population of hard clams, Mercenaria mercenaria, in Maine was discovered recently near the low intertidal in Goose Cove, in the town of Trenton (Hancock County). A fast- and slow-growing morph was identified that reaches commercial size (50.8 mm shell length) in 4 y and 5 y, respectively. Fast-growing individuals were selected as broodstock, and conditioned to spawn at the Downeast Institute. The fate and growth of cultured juveniles was followed for 5 mo beginning in July 2006 at 4 stocking densities (2,500–10,000 animals/1.1 m2 floating, nylon window screen-lined tray; n = 20) at a coldwater field nursery approximately 60 km east of Trenton, in the town of Beals, ME (Washington County). Survival was nearly 100%, and growth was density dependent, with animals attaining a final mean shell length ±95% confidence interval of 8.4 = 0.13 mm and 7.6 ± 0.218 mm in the lowest and highest density treatments, respectively. In November 2006, cultured seed was separated into 2 sizes (large, 8.7 ± 0.2 mm; small, 5.1 = 0.2 mm) and overwintered in window-screen bags (0.2 m2) at densities ranging from 0.6–1.6 kg (large) and 0.5–1 kg (small), representing approximate densities ranging from 3,360–15,510 individuals per bag. Bags were placed on horizontal shelves within modified lobster traps (overwintering containers) that were added to a 35,000-L tank receiving ambient seawater for 177 days until May 2007. Seawater temperatures during this interval ranged from -1-10°C. Survival rates exceeded 99%, and no negative effects resulting from stocking density were observed. Hatchery seed was transplanted in May 2007 to the lower intertidal at Goose Cove and a second intertidal location approximately 30 km east of Beals at Duck Brook Flat, in the town of Cutler, and the fate and growth of these juveniles was followed for 6–7 mo. Survival was independent of planting densities (330–1320 individuals/m2), and predator netting did not enhance survival compared with controls without netting. Growth was seasonal, with the greatest incremental shell increases occurring between early July and late September. Growth rates varied between planting locations, with clams adding approximately 10 mm shell length at Goose Cove between May and December (initial shell length, 8.2 mm; final shell length, 17.9 mm) and approximately 5 mm shell length at Duck Brook Flat between June and November (initial shell length, 9.3 mm; final shell length, 14.3 mm). Hard clam farming in eastern Maine may help to diversify a wild shellfish industry that is currently in decline for most species except lobsters; however, additional efforts are needed to explore alternative grow-out sites and methods to enhance growth rates.
