Enhancing Seed Availability For the Hard Clam (Mercenaria mercenaria) Aquaculture Industry By Applying Remote Setting Techniques

The goal of this study was to test a technology that may help ensure a reliable and consistent supply of high quality and inexpensive clam seed to growers, thus fostering an emerging aquaculture industry by eliminating a seed shortage that limits sustainability. The overall objectives were to develop, test and demonstrate technical procedures and determine the financial feasibility of transferring remote setting technology from the Pacific Northwest molluscan shellfish industry to the hard clam aquaculture industry in Florida. (PDF has 44 pages.)

Organizational Structures and Strategies For the Hard Clam Aquaculture Industry in Florida

This study provides guidance on statewide organization for the commercial hard clam culture industry in Florida. The study characterizes the structure of and identifies strategies for successful agricultural and aquacultural organizations designed to provide the resources needed to solve current and projected industry problems. Objectives were to 1) characterize the structure of successful and relevant organizations, 2) identify successful revenue generating strategies, 3) provide the hard clam culture industry with options to help facilitate their organizational decisions, and 4) assist clam growers in Florida in developing an umbrella organizational strategy that will meet their future industry needs. (PDF has 60 pages.)

Annotated bibliography II of the hard clam Mercenaria mercenaria

In this era of proliferating scientific information it is difficult to keep up with the literature, even in one's own field. Review articles are helpful in summarizing the status of knowledge. In oyster biology, several such published reviews have been of great help to working scientists. The outstanding contributions that come to' mind are those by Baughman (1948), Korringa (1952), Joyce (1972), Breisch and Kennedy (1980), and Kennedy and Breisch (198 I). If done well, such compilations serve as checkpoints, eliminating or vastly reducing the need to consult the literature in detail. On Long Island, New York, where the hard clam Mercenaria mercenaria is the major commercial resource, we have felt the need for some time for a compendium of knowledge on this important mollusk. Several years ago my secretary, students, and I began to gather materials for an annotated bibliography. We have already published a collection of 2233 titles (McHugh et al. 1982), nearly all accompanied by abstracts, and in this publication we have added another 460. The experience has been rewarding. We have been surprised at the extent of the literature, much of it only remotely related to the shellfish industry itself, but nevertheless throwing light on the biology, physiology, and many other aspects of the scientific knowledge of hard clams. The following bibliography is divided into three parts. Part I comprises the bulk of the bibliography, while Parts 2 and 3 contain additional titles that we decided to include during editing, submission, and approval of the manuscript for publication. All three parts are indexed together, however. We also reexamined those titles in the previous bibliography (McHugh et al. 1982) which did not include abstracts. These are included in Parts 2 and 3 of this bibliography. Most of these contained no specific reference to Mercenaria mercenaria. A few searches were terminated for various reasons. (PDF file contains 66 pages.)

A temporal and spatial study of invertebrate communities associated with hard-bottom habitats in the South Atlantic Bight

Species composition, biomass, density, and diversity of benthic invertebrates from six bard-bottom areas were evaluated. Seasonal collections using a dredge, trawl, and suction and grab samplers yielded 432, 525, and 845 taxa, respectively. Based on collections wltb the different gear types, species composition of invertebrates was found to change bathymetrically. Inner- and mlddle-shelf sites were more similar to each other in terms of invertebrate species composition than they were to outer-shelf sites, regardless of season. Sites on the inner and outer shelf were grouped according to latitude; however, results suggest that depth is apparently a more important determinant of invertebrate species composition than either season or latitude. Sponges generally dominated dredge and trawl collections in terms of biomass. Generally, cnidarians, bryozoans, and sponges dominated at sites In terms of number of taxa collected. The most abundant smaller macrofauna collected in suction and grab samples were polychaetes, amphipods, and mollusks. Densities of the numerically dominant species changed botb seasonally and bathymetrically, with very few of these species restricted to a specific bathymetrlc zone. The high diversity of invertebrates from hard-bottom sites is attributed to the large number of rare species. No consistent seasonal changes in diversity or number of species were noted for individual stations or depth zones. In addition, H and its components showed no definite patterns related to depth or latitude. However, more species were collected at middle-shelf sites than at inner- or outer-shelf sites, which may be related to more stable bottom temperature or greater habitat complexity in that area. (PDF file contains 110 pages.)

The effect of organotin and copper sulfate on the late development and presettlement behavior of the hard clam Mercenaria mercenaria

The effect of organotin compounds and copper, commonly used as antifouling agent, were studied on Mercenaria mercernaria larvae. They were reared under usual hatchery conditions until they reached 190 um in diameter. The larvae were subjected to four compounds, tributylin chloride (TBT), monobutyltin chloride (MBT), trimethyltin chloride (TMT), cupric sulfate (CuSo4) plus control. Mortality was measured at 24, 48 h, and 96h. Behavioral and/or metamorphic changes were recorded in triplicate at 24-48 and 96 h. The appearance in swimming larvae of a functional foot was considered a sign of competence to set and was recorded as a "pediveliger". Swimming larvae were considered as larvae that have not yet reached their total development and they were recorded as "swimming". Larvae that did not show foot or swimming activity and were static but alive on the bottom were recorded as "bottom". TBT was found to completely inhibit swimming activity at sublethal concentrations throughout the period of observation. Copper and MBT inhibited swimming from 48 h, TMT did not inhibit swimming activity at any of the times recorded. The four compounds ranked in order of decreasing toxicity were TBT>TMT>CU>MBT.

Influence of hard bottom morphology on fish assemblages of the continental shelf off Georgia, southeastern USA

Various reef types worldwide have inconsistent relationships among fish assemblage parameters and benthic characteristics, thus there is a need to identify factors driving assemblage structure specific to each reef type and locale. Limestone ledges are known to be key habitats for bottom fish on the continental shelf of the southeastern USA, however, the specific factors that link them to fish assemblages have not been quantified. Bottom fishes and habitat characteristics on ledges were surveyed at a study site located centrally in the southeastern USA continental shelf. Species richness, diversity, abundance, and biomass of fish were higher at ledges than on flat bottom. Species richness, abundance, and biomass of fish were well explained by ledge variables including percent cover of sessile invertebrates, total height, and height of undercut recesses. Multivariate analyses based on biomass of individual species at ledges revealed two fish assemblages associated with four ledge types. One assemblage was associated with ledges that were tall, heavily colonized with sessile invertebrates, large in area, and did or did not have undercuts. The other assemblage was associated with ledges that were short, not undercut, smaller in area, and were or were not heavily colonized by invertebrates. Seafloor classification schemes presently used in the region do not adequately capture hard bottom diversity to identify the location and extent of essential fish habitats for ecological and fisheries purposes. Given that ledges cover only ∼1% to 5% of the southeastern USA continental shelf, they merit the highest levels of consideration in regional research, conservation, and management plans.

Review on hard coral recruitment (Cnidaria: Scleractinia) in Colombia

Recruitment, defined and measured as the incorporation of new individuals (i.e. coral juveniles) into a population, is a fundamental process for ecologists, evolutionists and conservationists due to its direct effect on population structure and function. Because most coral populations are self-feeding, a breakdown in recruitment would lead to local extinction. Recruitment indirectly affects both renewal and maintenance of existing and future coral communities, coral reef biodiversity (bottom-up effect) and therefore coral reef resilience. This process has been used as an indirect measure of individual reproductive success (fitness) and is the final stage of larval dispersal leading to population connectivity. As a result, recruitment has been proposed as an indicator of coral-reef health in marine protected areas, as well as a central aspect of the decision-making process concerning management and conservation. The creation of management plans to promote impact mitigation,rehabilitation and conservation of the Colombian coral reefs is a necessity that requires firstly, a review and integration of existing literature on scleractinian coral recruitment in Colombia and secondly, larger scale field studies. This motivated us to summarize and analyze all existing information on coral recruitment to determine the state of knowledge, isolate patterns, identify gaps, and suggest future lines of research.

Hard days and nights: hardships at work, a lack of support at home, and little or no social security combine to create a bleak future for women fishsellers in Mangalore, India

Mangalore is a port city situated in the west coast state of Karnataka in India. The city hosts both large-scale and small-scale fisheries along its coastline. Traditionally, fishermen catch the product and sell it at a daily auction in the harbour to women vendors, who thereafter transport the goods to the market for commercial sale. The trade starts early in the morning, when the fishermen return to the harbour from their nightly fishing.