The Bay Scallop, Argopecten irradians, in Florida Coastal Waters

The bay scallop, Argopecten irradians, supported a small commercial fishery in Florida from the late 1920’s through the 1940’s; peak landings were in 1946 (214,366 lbs of meats), but it currently supports one of the most popular and family-oriented fisheries along the west coast of Florida. The primary habitat of the short-lived (18 months) bay scallop is seagrass beds. Peak spawning occurs in the fall. Human population growth and coastal development that caused habitat changes and reduced water quality probably are the main causes of a large decline in the scallop’s abundance. Bay scallop restoration efforts in bays where they have become scarce have centered on releasing pediveligers and juveniles into grass beds and holding scallops in cages where they would

The Bay Scallop, Argopecten irradians, Massachusetts Through North Carolina: Its Biology and the History of Its Habitats and Fisheries

This article covers the biology and the history of the bay scallop habitats and fishery from Massachusetts to North Carolina. The scallop species that ranges from Massachusetts to New York is Argopecten irradians irradians. In New Jersey, this species grades into A. i. concentricus, which then ranges from Maryland though North Carolina. Bay scallops inhabit broad, shallow bays usually containing eelgrass meadows, an important component in their habitat. Eelgrass appears to be a factor in the production of scallop larvae and also the protection of juveniles, especially, from predation. Bay scallops spawn during the warm months and live for 18–30 months. Only two generations of scallops are present at any time. The abundances of each vary widely among bays and years. Scallops were harvested along with other mollusks on a small scale by Native Americans. During most of the 1800’s, people of European descent gathered them at wading depths or from beaches where storms had washed them ashore. Scallop shells were also and continue to be commonly used in ornaments. Some fishing for bay scallops began in the 1850’s and 1860’s, when the A-frame dredge became available and markets were being developed for the large, white, tasty scallop adductor muscles, and by the 1870’s commercial-scale fishing was underway. This has always been a cold-season fishery: scallops achieve full size by late fall, and the eyes or hearts (adductor muscles) remain preserved in the cold weather while enroute by trains and trucks to city markets. The first boats used were sailing catboats and sloops in New England and New York. To a lesser extent, scallops probably were also harvested by using push nets, picking them up with scoop nets, and anchor-roading. In the 1910’s and 1920’s, the sails on catboats were replaced with gasoline engines. By the mid 1940’s, outboard motors became more available and with them the numbers of fishermen increased. The increases consisted of parttimers who took leaves of 2–4 weeks from their regular jobs to earn extra money. In the years when scallops were abundant on local beds, the fishery employed as many as 10–50% of the towns’ workforces for a month or two. As scallops are a higher-priced commodity, the fishery could bring a substantial amount of money into the local economies. Massachusetts was the leading state in scallop landings. In the early 1980’s, its annual landings averaged about 190,000 bu/yr, while New York and North Carolina each landed about 45,000 bu/yr. Landings in the other states in earlier years were much smaller than in these three states. Bay scallop landings from Massachusetts to New York have fallen sharply since 1985, when a picoplankton, termed “brown tide,” bloomed densely and killed most scallops as well as extensive meadows of eelgrass. The landings have remained low, large meadows of eelgrass have declined in size, apparently the species of phytoplankton the scallops use as food has changed in composition and in seasonal abundance, and the abundances of predators have increased. The North Carolina landings have fallen since cownose rays, Rhinoptera bonsais, became abundant and consumed most scallops every year before the fishermen could harvest them. The only areas where the scallop fishery remains consistently viable, though smaller by 60–70%, are Martha’s Vineyard, Nantucket, Mass., and inside the coastal inlets in southwestern Long Island, N.Y.

Quahogs in Eastern North America: Part II, History by Province and State

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 shells as scrapers and as utensils. The European colonists copied the Indians treading method, and they also used short rakes for harvesting quahogs. The Indians of southern New England and Long Island, N.Y., made wampum from quahog shells, used it for ornaments and sold it to the colonists, who, in turn, traded it to other Indians for furs. During the late 1600’s, 1700’s, and 1800’s, wampum was made in small factories for eventual trading with Indians farther west for furs. The quahoging industry has provided people in many coastal communities with a means of earning a livelihood and has given consumers a tasty, wholesome food whether eaten raw, steamed, cooked in chowders, or as stuffed quahogs. More than a dozen methods and types of gear have been used in the last two centuries for harvesting quahogs. They include treading and using various types of rakes and dredges, both of which have undergone continuous improvements in design. Modern dredges are equipped with hydraulic jets and one type has an escalator to bring the quahogs continuously to the boats. In the early 1900’s, most provinces and states established regulations to conserve and maximize yields of their quahog stocks. They include a minimum size, now almost universally a 38-mm shell width, and can include gear limitations and daily quotas. The United States produces far more quahogs than either Canada or Mexico. The leading producer in Canada is Prince Edward Island. In the United States, New York, New Jersey, and Rhode Island lead in quahog production in the north, while Virginia and North Carolina lead in the south. Connecticut and Florida were large producers in the 1990’s. The State of Tabasco leads in Mexican production. In the northeastern United States, the bays with large openings, and thus large exchanges of bay waters with ocean waters, have much larger stocks of quahogs and fisheries than bays with small openings and water exchanges. Quahog stocks in certified beds have been enhanced by transplanting stocks to them from stocks in uncertified waters and by planting seed grown in hatcheries, which grew in number from Massachusetts to Florida in the 1980’s and 1990’s.

Quahogs in Eastern North America: Part I, Biology, Ecology, and Historical Uses

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 shells as scrapers and as utensils. The European colonists copied the Indians treading method, and they also used short rakes for harvesting quahogs. The Indians of southern New England made wampum from quahog shells, used it for ornaments and sold it to the colonists, who, in turn, traded it to other Indians for furs. During the late 1600’s, 1700’s, and 1800’s, wampum was made in small factories for eventual trading with Indians farther west for furs. The quahoging industry has provided people in many coastal communities with a means of earning a livelihood and has provided consumers with a tasty, wholesome food whether eaten raw, steamed, cooked in chowders, or as stuffed quahogs. More than a dozen methods and types of gear have been used in the last two centuries for harvesting quahogs. They include treading and using various types of rakes and dredges, both of which have undergone continuous improvements in design. Modern dredges are equipped with hydraulic jets and one type has an escalator to bring the quahogs continuously to the boats. In the early 1900’s, most provinces and states established regulations to conserve and maximize yields of their quahog stocks. They include a minimum size, now almost universally a 38-mm shell width, and can include gear limitations and daily quotas. The United States produces far more quahogs than either Canada or Mexico. The leading producer in Canada is Prince Edward Island. In the United States, New York, New Jersey, and Rhode Island lead in quahog production in the north, while Virginia and North Carolina lead in the south. Connecticut and Florida were large producers in the 1990’s. The State of Campeche leads in Mexican production. In the northeastern United States, the bays with large openings, and thus large exchanges of bay waters with ocean waters, have much larger stocks of quahogs and fisheries than bays with small openings and water exchanges. Quahog stocks in certifi ed beds have been enhanced by transplanting stocks to them from stocks in uncertified waters and by planting seed grown in hatcheries, which grew in number from Massachusetts to Florida in the 1980’s and 1990’s.

Assobios do boto-cinza, Sotalia guianensis, (Cetacea, Delphinidae) em três áreas de concentração na costa do Rio de Janeiro

A espécie Sotalia guianensis apresenta um variado repertório de assobios que estão ligados a interação social e a diferentes contextos de comportamento. As variações intraespecíficas nas estruturas dos assobios podem indicar diferenças entre populações dessa espécie. O presente estudo caracterizou e comparou o repertório dos assobios de Sotalia guianensis, em três baías do estado do Rio de Janeiro: Baía de Guanabara (BG), Baía de Sepetiba (BS) e Baía da Ilha Grande (BI), utilizando um sistema de gravação com limite superior de frequência de 48 kHz e através da aplicação das análises quantitativas e qualitativas dos parâmetros acústicos. As gravações dos assobios foram realizadas com embarcações de 5,5 e 7m e sistema de gravação composto por um hidrofone High Tech, modelo HTI-96-MIN, e um gravador digital modelo PMD 671 Marantz, com limite superior de frequência de 48 kHz. As análises dos espectrogramas foram realizadas com os softwares Adobe Audition 1.5 e Raven 1.3. Os assobios foram classificados em seis categorias de forma de contorno e 11 parâmetros acústicos foram medidos para cada assobio. Para comparar os parâmetros acústicos de mesma forma de contorno entre as três baías, foram aplicados a análise descritiva e testes estatísticos de comparação de média. Um total de 1800 assobios foi selecionado e 61,38% (N=1105) dos assobios apresentaram forma de contorno ascendente. Assobios com zero ou um ponto de inflexão foram mais frequentes (N=1476), correspondendo a 82%. A amplitude de frequência encontrada variou de 1,03 a 46,87 kHz, maior alcance registrado para essa espécie no Brasil. A média de duração dos assobios da BG foi menor do que as médias encontradas na BS e na BI. Os resultados de todas as comparações realizadas demonstraram que os parâmetros de frequência (FI, FF, FMAX e F3/4) foram os que mais apresentaram diferenças significativas entre as três áreas. A variação encontrada nos assobios de S. guianensis entre as três áreas estudadas pode também estar ligada aos tipos de assobios mais comuns em cada área, representados pelos assobios ascendentes, que apesar de apresentarem a mesma forma de contorno, possuem diferenças em seus parâmetros acústicos, possivelmente ligados a informações individuais. A utilização de um sistema de gravação com limite superior de 48 kHz possibilitou a análise de muitos assobios. Com isso, foi possível verificar a importância do limite de frequência aplicado para caracterizar o repertório acústico dessa espécie, juntamente com as análises qualitativas das formas de contorno e as análises quantitativas dos parâmetros acústicos dos assobios. A aplicação dessa metodologia foi eficaz na comparação intraespecífica dos assobios, e futuramente, estudos mais detalhados da classificação dos assobios, poderá acrescentar informações relevantes sobre a variação desse tipo de emissão sonora no repertório acústico S. guianensis

Menhaden: The Resource, The Industry, and a Management History

PREFACE: Four species of menhaden, Brevoortia spp., are found along the Atlantic and Gulf of Mexico coasts of the United States. The Atlantic menhaden, B. tyrannus, is found from Nova Scotia, Can., to West Palm Beach, Fla.; the yellowfin menhaden, B. smithi, is found from Cape Lookout, N. C., to the Mississippi River Delta, La.;the Gulf menhaden, B. patronus, is found from Cape Sable, Fla., to Veracruz, Mex.; and the finescale menhaden, B. gunteri, is found from the Mississippi River Delta, La., to Campeche, Mex. Menhaden are euryhaline species that inhabit coastal and inland tidal waters. Spawning occurs principally at sea (in northern areas some spawning occurs in bays and sounds). Eggs hatch at sea and the larvae are moved to estuaries by ocean currents where they metamorphose and develop as juveniles.

Population Biology and Life History of the North American Menhadens, Brevoortia spp.

Four recognized species of menhaden, Brevoortia spp., occur in North American marine waters: Atlantic menhaden, B. tyrannus; Gulf menhaden, B. patronus; yellowfin menhaden. B. smithi; and finescale menhaden, B. gunteri. Three of the menhaden species are known to form two hybrid types. Members of the genus range from coastal waters of Veracruz, Mex., to Nova Scotia, Can. Atlantic and Gulf menhaden are extremely abundant within their respective ranges and support extensive purse-seine reduction (to fish meal and oil) fisheries. All menhaden species are estuarine dependent through late larval and juvenile stages. Depending on species and location within the range, spawning may occur within bays and sounds to a substantial distance offshore. Menhaden are considered to be filter-feeding, planktivorous omnivores as juveniles and adults. Menhaden eggs, immature developmental stages, and adults are potential prey for a large and diverse number of predators. North American menhadens, including two hybrids, are hosts for the parasitic isopod, Olencira praegustator, and the parasitic copepod, Lemaeenicus radiatus. Although the data are quite variable, a dome-shaped Ricker function is frequently used to describe the spawner-recruitment relationship for Atlantic and Gulf menhaden. Each of these species is treated as a single stock with respect to exploitation by the purse-seine reduction fishery. Estimates of instantaneous natural (other) mortality rates are O.45 for Atlantic menhaden and 1.1 for Gulf menhaden.

Diet of Bottlenose Dolphins Tursiops truncatus in the Northwest Panhandle and Foraging Behavior Near Savannah, Georgia

The foraging ecology of bottlenose dolphins Tursiops truncatus in the Northwest Florida Panhandle and estuaries in northern Georgia was determined using diet analysis and behavioral surveys. Stomach content analysis was completed on bottlenose dolphins(N = 25) that stranded in the Northwest Florida Panhandle from November 2006 to March 2009. The most abundant prey species were spot Leiostomus xanthurus (20.4%), squid (10.9%), pinfish Lagodon rhombiodes (10.3%), and Atlantic croaker Micropogonias undulatus (8.5%). Dolphins that stranded during months with a red tide Karenia brevis bloom consumed more pinfish, and spot; whereas dolphins that stranded in non-bloom months consumed more squid, Atlantic croaker, and silver perch Bairdiella chrysoura. Differences in diet were also identified for dolphins that stranded inside bays/sound and dolphin that stranded outside of bays along the coast, and male and female dolphins. Surveys were conducted from south of the Savannah River to north of Ossabaw Sound in Georgia where foraging behaviors were classified. Multivariate Generalized Additive Models were used to test correlations of behaviors to dolphin group size, depth, salinity, temperature, creek width, and tide. Sightings with headstands (p = 0.009), hard stops (p = 0.019), chasing (p = 0.004), mudbank whacking (p < 0.001), herding/circling (p = 0.024), and strand feeding (p = 0.006) were correlated with shallow water or small creeks. Sightings with kerplunking (p = 0.031), mudbank whacking (p = 0.001), strand feeding (p = 0.003), and herding/circling (p = 0.026) were significantly correlated with low tide. The results of the Savannah, Georgia study were the first to characterize foraging behaviors in this area and demonstrate how bottlenose dolphins utilize the salt marsh estuary in terms of foraging. Studies like these are important to determine how dolphins forage efficiently and to provide background information on diet and foraging behavior for use in monitoring future impacts to dolphins in the Northwest Florida Panhandle and near Savannah, Georgia.

Foraminíferos como indicadores paleoecológicos do Holoceno no Manguezal de Guaratiba, Baía de Sepetiba, Rio de Janeiro

Os manguezais são ecossistemas estuarinos, representando a transição entre os ambientes continentais e marinhos, e tendo sua formação relacionada com as flutuações do nível do mar no Quaternário. No Manguezal de Guaratiba, diversos estudos sobre as variações do nível do mar, mais precisamente no Holoceno, têm sido realizados, sob os enfoques sedimentológicos, geoquímicos, palinológicos e micropaleontológicos. Entre os estudos micropaleontológicos, destacam-se os que utilizam os foraminíferos bentônicos, micro-organismos amplamente utilizados como indicadores paleoecológicos e paleoambientais do Holoceno. No presente trabalho, foi coletado, através de um amostrador do tipo trado russo, um testemunho (T1) no Manguezal de Guaratiba, no qual foram realizadas análises de parâmetros como granulometria, teores de matéria orgânica (MO), carbonato, carbono orgânico total (COT) e enxofre (S) (abióticos) e da fauna de foraminíferos bentônicos (bióticos). Foram utilizadas também índices ecológicos e análises de agrupamento, através das quais foi possível estabelecer quatro associações faunísticas (I,II,III e IV), assim como os fatores ambientais que mais influenciaram a distribuição da fauna. A correlação com assembleias de foraminíferos de outros testemunhos que possuem datação por Carbono 14 (C14), assim como outros trabalhos que versam sobre a evolução da Baía de Sepetiba, permitiu o estabelecimento de três ciclos de emersão-submersão para a área da planície de maré estudada: 1)Fase transgressiva: nível de concentração de conchas em depósitos lagunares formados por sedimentos finos, sem foraminíferos; provavelmente posterior a uma regressão; 2) Fase transgressiva: formação de uma baía, com presença exclusiva de espécies de foraminíferos calcários (Associação III) com maiores valores de riqueza e queda nos valores de COT; ocorrida há cerca de 3.800 anos A.P 3) Fase transgressiva: período de submersão, presença de espécies de foraminíferos tipicamente estuarinos (Associação IV), com duração entre 3.500 anos A.P. e 2.700 anos A.P.; 4)Fase transgressiva: caracterizada pela alternância entre a formação de baías rasas e lagunas marinhas (maiores índices de riqueza nas associações faunísticas), menores valores de MO e COT e aumento na proporção de sedimentos finos; evento iniciado há cerca de 2.700 anos A.P.; e 5)Fase regressiva: fauna de foraminíferos aglutinantes, resistente às condições de salinidade e acidez características de ambientes confinados como os manguezais, além do incremento nos teores de areia, evidenciando a fase final de confinamento da Baía de Sepetiba pela Restinga da Marambaia; evento iniciado por volta de 2.400 anos A.P., estendendo-se até o presente. Os resultados obtidos mostram a importância da correlação lateral entre testemunhos na interpretação paleoambiental da Baía de Sepetiba, além da identificação de estágios de transgressão e regressão que se aproximam da curva de variação do nível do mar proposta por SUGUIO et al.(1985) para o litoral do Estado do Rio de Janeiro

Estudo isotópico e geoquímico dos sedimentos costeiros da Costa Verde do Estado do Rio de Janeiro para identificação de atividades antrópicas

A Costa Verde se localiza no estado do Rio Janeiro, onde também está localizada a Ilha Grande, importante polo turístico do estado. É composta pelas baías Sepetiba e Ilha Grande, que podem ser compartimentadas em diversas enseadas. As principais enseadas são Sepetiba, Marambaia, Mangaratiba, Angra dos Reis, Ribeira, Frade e Paraty. O presente estudo foi realizado nas enseadas de Mangaratiba, Angra dos Reis e Ribeira e foram compilados dados de Sepetiba e Marambaia estudado por outros autores. O objetivo do estudo destas enseadas foi identificar os metais e suas fontes e os mecanismos que os controlam, além de propor novos parâmetros de concentração de metais que indiquem processos de contaminação. O método utilizado foi a coleta de sedimento de fundo através da utilização de Van Veen e analisados por digestão total em espectrômetro de massa da qual se obteve a concentração dos elementos Ca, Cd, Co, Cr, Cu, K, Pb, Na, Ni, Sr, S, U, V e Zn, além das razões isotópicas de chumbo, com prioridade da razão 206Pb/207Pb. Foram obtidos resultados que indicam que a enseada de Mangaratiba apresenta as maiores concentrações de metais e com predominante contribuição antrópica cujas fontes são, os empreendimentos localizados na costa dessa enseada, incluindo o TEBIG. A enseada de Angra dos Reis também apresenta concentrações elevadas de metais, provenientes de efluentes domésticos, rejeito industrial ao qual se inclui o estaleiro Verolme e com forte controle do embasamento da enseada. A enseada da Ribeira tem seus metais fornecidos pelo porto de Bracuhy e uma fonte desconhecida que são controlados, em parte, pelos efluentes da CNAAA. Em relação a interação entre as cinco enseadas existe mútua troca de metais controlados pela dinâmica da Costa e acentuada pelo Canal de Ilha Grande (que liga as duas baias), onde a dispersão dos metais também é controlada por temperatura, fração sedimentar, profundidade e salinidade. Os principais metais relacionados às fontes antrópicas na Costa Verde são Co, Cr, Cu, Mn, Ni, Pb e Zn. As concentrações hoje apresentadas na resolução CONAMA não atendem a realidade da Costa Sul brasileira, sendo então propostos novos parâmetros de controle, menos permissivo

Attenuation of self-generated tactile sensations is predictive, not postdictive.

When one finger touches the other, the resulting tactile sensation is perceived as weaker than the same stimulus externally imposed. This attenuation of sensation could result from a predictive process that subtracts the expected sensory consequences of the action, or from a postdictive process that alters the perception of sensations that are judged after the event to be self-generated. In this study we observe attenuation even when the fingers unexpectedly fail to make contact, supporting a predictive process. This predictive attenuation of self-generated sensation may have evolved to enhance the perception of sensations with an external cause.

Characterization of toxic impacts on living marine resources in tidal rivers of the Chesapeake Bay

In 1999, the Chesapeake Bay Program completed a survey of existing data on chemical contaminants and the potential for bioeffects in 38 tidal river systems of Chesapeake Bay. This review led to the identification of 20 areas for which there were insufficient data to adequately characterize the potential for contaminant bioeffects on the Bay’s living resources. The goal of the present study was to estimate the current status of ecological condition in five of these areas and thus help to complete the overall toxics inventory for the Bay. These five systems included the Chester River, Nanticoke River, Pocomoke River, Lower Mobjack Bay (Poquosin and Back Rivers) and the South and Rhode Rivers. This study utilized a Sediment Quality Triad (SQT) approach in combination with additional water-column contaminant analysis to allow for a “weight of evidence” assessment of environmental condition. A total of 60 stations distributed among the five systems, using a probabilistic stratified random design, were sampled during the summer of 2004 to allow for synoptic measures of sediment contamination, sediment toxicity, and benthic condition. Upon completion of all analyses, stations were assigned to one of four categories based on the three legs of the triad. Stations with high sediment quality had no hits on any of the three legs of the triad; those with moderate quality had one hit; those with marginal quality had two hits; and those with poor quality had hits for all three legs of the triad. The Pocomoke River had by far the largest proportion of the total area (97.5%) classified as having high sediment quality, while the Rhode/South system had the highest proportion (11.4%) classified as poor. None of the stations in the Chester River, Nanticoke River, and Lower Mobjack Bay systems were classified as poor. More than 65% of the area of each of the five systems was classified with high to moderate sediment quality. The Rhode/South system had 30.4% of total area classified with marginally to severely poor quality. The results of this study highlight the importance of using multiple indicators and a “weight of evidence” approach to characterize environmental quality and the potential bioeffects of toxic contaminants.