Maerl grounds provide both refuge and high growth potential for juvenile queen scallops (Aequipecten opercularis L.)

Human damage to biogenic substrata such as maerl has been receiving increasing attention recently. Maerl forms highly biodiverse and heterogeneous habitats composed of loose-lying coralline red algae, which fulfil nursery area prerequisites for queen scallops (Aequipecten opercularis) and other invertebrates. The benefits obtained by queen scallops utilising maerl were poorly understood, so we used both laboratory predation and field tethering experiments to investigate the refuge and growth potential provided by pristine live maerl (PLM) grounds over other common substrata. In aquaria, more juvenile queen scallops (&lt;35 mm shell height) survived on PLM than on gravel substrata in the presence of the crab Carcinus maenas or the starfish Asterias rubens. Field tethering experiments indicated similar survivorship of juvenile queen scallops on PLM and gravel; additionally, their growth rates were similar on both substrata. PLM allows scallops to seek refuge from predators and position themselves to optimise their food supply. Other bivalve refugia have been shown to provide poor food supply as a consequence of their high heterogeneity, yet maerl grounds provide a 'win-win' scallop nursery area coupling refuge availability with high food supply. </p

Aquaculture and marketing of the Florida Bay Scallop in Crystal River, Florida

The overall goal of this study was to develop a new fishery resource product through open-water aquaculture for the west coast of Florida that would compete as a non-traditional product through market development. Specific objectives were as follows: I. To grow a minimum of 50, 000 juvenile scallops to a minimum market size of40 mm in a cage and float system in the off-shore waters of Crystal River, Florida. 2. To determine the growth rate, survival, and time to market size for the individuals in this system and area to other similar projects like Virginia. 3. To introduce local fishermen and the aquaculture students at Crystal River High School to the hatchery, nursery, and grow-out techniques. 4. To determine the economic and financial characteristics of bay scallop culture in Florida and assess the sensitivity of projected costs and earnings to changes in key technical, managerial, and market related parameters. 5. To determine the market acceptability and necessary marketing strategy for whole bay scallop product in Florida. (PDF has 99 pages.

Effects of harvesting methods on sustainability of a bay scallop fishery: dredging uproots seagrass and displaces recruits

Fishing is widely recognized to have profound effects on estuarine and marine ecosystems (Hammer and Jansson, 1993; Dayton et al., 1995). Intense commercial and recreational harvest of valuable species can result in population collapses of target and nontarget species (Botsford et al., 1997; Pauly et al., 1998; Collie et al. 2000; Jackson et al., 2001). Fishing gear, such as trawls and dredges, that are dragged over the seafloor inflict damage to the benthic habitat (Dayton et al., 1995; Engel and Kvitek, 1995; Jennings and Kaiser, 1998; Watling and Norse, 1998). As the growing human population, over-capitalization, and increasing government subsidies of fishing place increasing pressures on marine resources (Myers, 1997), a clear understanding of the mechanisms by which fishing affects coastal systems is required to craft sustainable fisheries management

Bay Scallops, Argopecten irradians, in the Northwestern Gulf of Mexico (Alabama, Mississippi, Louisiana, and Texas)

There is no evidence that a commercial bay scallop fishery exists anywhere in the northwestern Gulf of Mexico. No data concerning scallop abundance or distribution was found for Alabama, Mississippi, and Louisiana. Texas is the only state west of Florida where bay scallop populations have been documented. These records come from a variety of literature sources and the fisheries-independent data collected by Texas Parks and Wildlife Department (1982–2005). Although common in the diet of prehistoric peoples living on the Texas coast, recent (last ~50 years) bay scallop population densities tend to be low and exhibit “boom–bust” cycles of about 10–15 years. The Laguna Madre, is the only place on the Texas coast where scallops are relatively abundant; this is likely due to extensive seagrasses cover (>70%) and salinities that typically exceed 35 psu. The lack of bay scallop fishery development in the northwestern Gulf of Mexico is probably due to variable but generally low densities of the species combined with a limited amount of suitable (i.e. seagras

Measurement errors in body size of sea scallops (Placopecten magellanicus) and their effect on stock assessment models

Body-size measurement errors are usually ignored in stock assessments, but may be important when body-size data (e.g., from visual sur veys) are imprecise. We used experiments and models to quantify measurement errors and their effects on assessment models for sea scallops (Placopecten magellanicus). Errors in size data obscured modes from strong year classes and increased frequency and size of the largest and smallest sizes, potentially biasing growth, mortality, and biomass estimates. Modeling techniques for errors in age data proved useful for errors in size data. In terms of a goodness of model fit to the assessment data, it was more important to accommodate variance than bias. Models that accommodated size errors fitted size data substantially better. We recommend experimental quantification of errors along with a modeling approach that accommodates measurement errors because a direct algebraic approach was not robust and because error parameters were diff icult to estimate in our assessment model. The importance of measurement errors depends on many factors and should be evaluated on a case by case basis

The History, Present Condition, and Future of the Molluscan Fisheries of North and Central American and Europe: Volume 1, Atlantic and Gulf Coasts

This three-volume monograph represents the first major attempt in over a century to provide, on regional bases, broad surveys of the history, present condition, and future of the important shellfisheries of North and Central America and Europe. It was about 100 years ago that Ernest Ingersoll wrote extensively about several molluscan fisheries of North America (1881, 1887) and about 100 years ago that Bashford Dean wrote comprehensively about methods of oyster culture in Europe (1893). Since those were published, several reports, books, and pamphlets have been written about the biology and management of individual species or groups ofclosely related mollusk species (Galtsoff, 1964; Korringa, 1976 a, b, c; Lutz, 1980; Manzi and Castagna, 1989; Shumway, 1991). However, nothing has been written during the past century that is comparable to the approach used by Ingersoll in describing the molluscan fisheries as they existed in his day in North America or, for that matter, in Europe. (PDF file contains 224 pages.

The History, Present Condition, and Future of the Molluscan Fisheries of North and Central America and Europe: Volume 3, Europe

(PDF file contains 248 pages.

The Bay Scallop, Argopecten irradians amplicostatus, in Northeastern Mexico

The bay scallop, Argopecten irradians amplicostatus, has been present in the coastal lagoons of northeastern Mexico from Laguna Madre, Tamaulipas, to Tuxpan, Veracruz. But now, usually scarce in all lagoons, the scallop is harvested sporadically by fishermen who wade and collect them by hand and with tongs. Some are eaten by the fishermen and some are sold. They bring the fishermen about 60 pesos (5.88US$)/kg. Only the adductor muscles are eaten; they are prepared in cocktails and in ceviche. Little evidence exists that this scallop species was used in the early Mexican cultures

Dockside Shellfish Aquaculture Project, Smith, B

The intent of this project was to train private dock owners and marina personnel how to deploy and maintain “spat collectors” under their docks in an effort to capture commercially important shellfish larvae, scallops and oysters in particular, with a minimum amount of effort and cost. The New Hampshire Estuaries Project (NHEP) provided major funding for this phase of the project, with addition funding from the New Hampshire Department of Environmental Services (NHDES) and the Gulf of Maine Council (GOMC). This year’s effort expands upon the pilot studies that were funded previously by the New Hampshire Coastal Program (NHCP) and the Greater Piscataqua Community Foundation (GPCF). The larvae of most shellfish are free swimming, and can be carried by the tides, currents and wind a great distance. Most of the larvae never survive due to predation and lack of suitable habitat. If it were possible to capture even a small percentage of the larvae within a suitable predator free habitat, the resulting grown out shellfish could be used to enhance the existing beds of wild population shellfish. There are such programs currently being managed, including the Wild Scallop Enhancement Program in Maine and the Oyster Gardening Project on Chesapeake Bay. AERC was able to recruit a number of volunteers, or “Shellfish Stewards”, from the entire seacoast region to join in the project. Although there were challenges, the project was a success. The scallop spat collectors proved to work efficiently with minimal loss over the winter. Lots of shellfish larvae were found growing in the spat bags, with no predators present. Unfortunately, none of the targeted species were found in the bags. The oyster bags did not work as well; only three of the nine bags were covered to date. They may weigh too much, or have fouled too heavily and sank. The bags recovered had lots of shellfish spat growing on them, just no oysters. The next logical step in future efforts with the dockside aquaculture projects would be to consider the options of placing “pre-seeded” collectors onto the sites. AERC attempted to import scallops from the Maine enhancement program last summer as a contingency plan, but the transfer never occurred due to weather and logistical problems encountered at the time. AERC would like to thank our funding agencies for their support and aid in this research. Thanks as well to all of our shellfish stewards who dedicated their dock space, time and effort to help restore an important natural resource. Special thanks to Bill Marshall of the New Castle Conservation Committee, who was instrumental in recruiting our many shellfish stewards in New Castle. Bill also assisted the AERC staff in the deployment phase and was even there to tow us out of the mud during the retrieval operations