Particulate matter removal by shellfish was quantified in several geographic locations, across several years. Data include filter and shellfish tissue weights.

This project will assess the ecosystem services of shellfish farming by measuring impacts of newly established farms in the North Carolina Research Reserve. Because there is an opportunity to assess conditions before farm installation, North Carolina estuaries provide an ideal place to measure these effects. Two years of intensive sampling in and adjacent to oyster farms, concentrating on wild shellfish resources and the physical and chemical environment, will aim to link small-scale changes with larger-scale ecosystem-level alterations. Coastal managers, state agencies, and shellfish farmers will provide input throughout the course of the project to ensure that the study parameters align with decision-making needs. The project will culminate with the production of visualization tools and models to allow resource managers, culturists, and reserve staff members to make better decisions when determining the locations and scales of shellfish farming operations.

This project team will leverage a well established collaborative group, GTM Reserve’s Oyster and Water Quality Task Force and engage additional users, including state agencies, nonprofits and the oyster fishery community that are working to improve water quality in Guana River Estuary. To assist with the development of restoration and management plans, this project will: 1) identify sources of nutrients to the Guana River Estuary, and determine how nutrient loads from the lake to the river are affected by hydrology and land use; 2) map the current distribution of shellfish communities; 3) quantify filtration and nitrogen removal by shellfish; and 4) conduct field and lab experiments to assess how water quality affects shellfish health, and also how shellfish affect water quality in the estuary. In collaboration with project end users, the project team will generate a suite of research products, including a coupled hydrodynamic-biogeochemical model for Guana Lake and monitoring and restoration recommendations. Project findings will be shared through a stakeholder workshop exploring ways to reduce nutrient inputs into the estuary, a training program for using shellfish for water quality remediation, and peer-reviewed and outreach publications.

Our experience with juvenile sablefish and long term rearing of broodstock indicate that salmon grower feeds currently used by commercial sablefish farmers for grow out are not optimally formulated to support maximum growth and efficient feed conversion. However, there are no published studies examining the effects of dietary nutrient balance on productive performance and growth at any post larval life-history stage for this species, and there are currently no commercial diets specifically formulated for sablefish in the marketplace. Because of the large impact of feed cost on the economic viability of farming sablefish, we are focusing on grow out diets intended for use during the post larval stages of development when the fish are being reared to harvest size. In this research, we use a novel statistical mixture model and response surface analysis method to determine the optimal level of dietary protein, lipid and digestible carbohydrate for testing. This approach permits simultaneous testing of diet formulations encompassing the full range of protein, lipid and digestible carbohydrate that can be produced commercially using today’s most advanced extrusion feed manufacturing technology. Raw data on rearing densities, tanks, water temperature, mortalities, ration and feed size may be available.

Milford lab maintains data sets relating to a variety of growth and physiology trials. These include husbandry techniques (i.e. stocking density, container size, change frequency, feed delivery method) of various bivalve species such as the Eastern oyster (Crassostrea virginica) and the bay scallop (Argopecten irradians). Data sets also cover experiments which have looked at effects of climate change (food availability and CO2 concentration) on growth and survival of surfclams (Spissula solidissima), bay scallops, and sea scallops.

The effects of hydraulic shellfish harvesting on the ecology of biological communities and chemistry of benthic sediments were investigated through a series of experiments conducted over a 5-year period from 2009 to 2013. Studies on a variety of different clam beds were undertaken in collaboration with local shellfish harvesters. Sediment samples were collected over the summer and early fall (June to October) and sorted to identify and count benthic organisms and to measure chemical parameters (e.g., pH, oxygen, aragonite saturation state), at the sediment/water interface. Comparisons of dredged to not dredged seafloor found that the effects of season (date of sampling) and location (sediment grain size) exceeded those of shellfish harvesting. Numbers of newly settled bivalves were often higher on recently harvested bottom. Shallow inshore marine communities appear to be highly resilient to disturbance, whether natural or manmade. Shellfish harvesting had only minor impacts on the ecology of seafloor communities and on chemistry of marine sediments.

There is increasing global awareness of the need for sustainable aquaculture. Aquaculture represents a potential mechanism for supplementing wild fish harvests, either through stocking of cultured animals or farming to market size. In the first case, stocked animals would be available to sport and commercial fishermen. In the latter, consumer demand would be met directly with a farmed product, reducing pressure on wild stocks. By the year 2030, the global population is projected to reach 8.2 billion, with an expected demand for seafood of 150 million metric tons (mmt), 54 mmt of which the Food and Agriculture Organization (www.fao.org) estimates that aquaculture must contribute. Meanwhile in the U.S., an astounding 86% of the seafood consumed is imported ($9 billion annually), which makes seafood second only to oil as the largest natural resource contributor to our national trade deficit. There remains a great need for U.S. aquaculture production to fill the seafood void. Commercial-scale production of marine finfish in the U.S. is limited to a handful of species, however, including red drum, Pacific threadfin, cobia, cod, and flounder (excluding the anadromous Atlantic salmon), and production is often inconsistent. On the U.S. West Coast, many native marine species represent good potential candidates for aquaculture. Most of these, such as California sheephead, California halibut, cabezon, lingcod, white seabass, and rockfishes, are fully or over-exploited by capture fisheries. Other high-value species like California yellowtail and yellowfin tuna are transitory, with apparently healthy populations, but based on success elsewhere in the world, are believed to offer excellent potential for commercial aquaculture development in the U.S. A major step in the creation of a viable and profitable marine aquaculture industry lies in developing reliable fingerling production, and central to this is understanding the variables that determine egg and larval quality. The lack of knowledge in what optimizes egg and larval quality is an important limiting factor in developing culture techniques for any species (Kjorsvik et al. 1990; Bromage 1995). Inconsistent or poor egg quality significantly affects the production and viability of larval and juvenile fish. In the absence of high-quality eggs, it is not possible to optimize husbandry practices because larval performance is substandard under typical culture conditions, such as high stocking densities, aggressive weaning regimes, and grading or other handling procedures. Unfortunately, identifying simple indicators of egg quality has been difficult as no individual metric is universally applicable within and among species. This proposal seeks to identify easy-to-use indictors, as well as determine pre- and post-spawning factors that affect egg quality, in up to three very different ecologically and economically valuable marine fish species native to the U.S. West Coast: a highly-pelagic finfish, the California yellowtail (Seriola lalandi; CYT); a deep-sea whitefish, the sablefish (Anoplopoma fimbria; SF); and/or a semi-resident benthic flatfish species, the California halibut (Paralichthys californicus; CH). All three species are multiple batch spawners, producing large numbers of eggs several times over the course of a spawning season. Defining the differences between high and low quality eggs and documenting correlations between quality and different conditions (e.g. broodstock diet, age, domestication status, spawning methods, or progression through the spawning season) will directly impact the success of culturing species like these. If inferior batches of eggs can be identified early on, culturists would have a valuable tool, which would significantly advance mariculture development along the U.S. West Coast and elsewhere by leading toward consistent fingerling production of species with great potential for culture.

Feed costs and time to harvest are key factors affecting the economic viability of domestic sablefish (Anoplopoma fimbria) aquaculture. Use of fast growing all-female monosex stocks dramatically reduces time to harvest, but our research to date indicates that the commercial salmon feeds typically used by industry are not optimally formulated for sablefish and there is still a high degree of potential for improved growth and feed conversion. The effects of dietary balance of protein, fat, and carbohydrate on productive performance, growth and feed conversion at any post-juvenile stage of development are unknown, and there are no commercial diets specifically formulated for sablefish aquaculture in the marketplace. Dietary nutrient imbalances combined with inappropriate feeding schedules and strategies contribute to poor nutrient utilization and are unlikely to fully support the growth potential of this species, impeding continued efforts to improve performance during grow-out to harvest. Thus, research activity focuses on establishing performance optimized diets and feeding strategies that support maximum growth, efficient feed conversion and other economically important traits such as fillet yield. Raw data on rearing densities, tanks, water temperature, mortalities, ration and feed size may be available.