Support for Integrated Ecosystem Assessments of NOAA’s National Estuarine Research Reserves System (NERRS), Volume II: Assessment of Ecological Condition and Stressor Impacts in Subtidal Waters of the North Carolina NERRS

A study was conducted to assess the status of ecological condition and potential human-health risks in subtidal estuarine waters throughout the North Carolina National Estuarine Research Reserve System (NERRS) (Currituck Sound, Rachel Carson, Masonboro Island, and Zeke’s Island). Field work was conducted in September 2006 and incorporated multiple indicators of ecosystem condition including measures of water quality (dissolved oxygen, salinity, temperature, pH, nutrients and chlorophyll, suspended solids), sediment quality (granulometry, organic matter content, chemical contaminant concentrations), biological condition (diversity and abundances of benthic fauna, fish contaminant levels and pathologies), and human dimensions (fish-tissue contaminant levels relative to human-health consumption limits, various aesthetic properties). A probabilistic sampling design permitted statistical estimation of the spatial extent of degraded versus non-degraded condition across these estuaries relative to specified threshold levels of the various indicators (where possible). With some exceptions, the status of these reserves appeared to be in relatively good to fair ecological condition overall, with the majority of the area (about 54%) having various water quality, sediment quality, and biological (benthic) condition indicators rated in the healthy to intermediate range of corresponding guideline thresholds. Only three stations, representing 10.5% of the area, had one or more of these indicators rated as poor/degraded in all three categories. While such a conclusion is encouraging from a coastal management perspective, it should be viewed with some caution. For example, although co-occurrences of adverse biological and abiotic environmental conditions were limited, at least one indicator of ecological condition rated in the poor/degraded range was observed over a broader area (35.5%) represented by 11 of the 30 stations sampled. In addition, the fish-tissue contaminant data were not included in these overall spatial estimates; however, the majority of samples (77% of fish that were analyzed, from 79%, of stations where fish were caught) contained inorganic arsenic above the consumption limits for human cancer risks, though most likely derived from natural sources. Similarly, aesthetic indicators are not reflected in these spatial estimates of ecological condition, though there was evidence of noxious odors in sediments at many of the stations. Such symptoms reflect a growing realization that North Carolina estuaries are under multiple pressures from a variety of natural and human influences. These data also suggest that, while the current status of overall ecological condition appears to be good to fair, long-term monitoring is warranted to track potential changes in the future. This study establishes an important baseline of overall ecological condition within NC NERRS that can be used to evaluate any such future changes and to trigger appropriate management actions in this rapidly evolving coastal environment. (PDF contains 76 pages)

Support for Integrated Ecosystem Assessments of NOAA’s National Estuarine Research Reserves System (NERRS), Volume I: The Impacts of Coastal Development on the Ecology and Human Well-being of Tidal Creek Ecosystems of the US Southeast

A study was conducted, in association with the Sapelo Island and North Carolina National Estuarine Research Reserves (NERRs), to evaluate the impacts of coastal development on sentinel habitats (e.g., tidal creek ecosystems), including potential impacts to human health and well-being. Uplands associated with southeastern tidal creeks and the salt marshes they drain are popular locations for building homes, resorts, and recreational facilities because of the high quality of life and mild climate associated with these environments. Tidal creeks form part of the estuarine ecosystem characterized by high biological productivity, great ecological value, complex environmental gradients, and numerous interconnected processes. This research combined a watershed-level study integrating ecological, public health and human dimension attributes with watershed-level land use data. The approach used for this research was based upon a comparative watershed and ecosystem approach that sampled tidal creek networks draining developed watersheds (e.g., suburban, urban, and industrial) as well as undeveloped sites. The primary objective of this work was to clearly define the relationships between coastal development with its concomitant land use changes and non-point source pollution loading and the ecological and human health and well-being status of tidal creek ecosystems. Nineteen tidal creek systems, located along the southeastern United States coast from southern North Carolina to southern Georgia, were sampled during summer (June-August), 2005 and 2006. Within each system, creeks were divided into two primary segments based upon tidal zoning: intertidal (i.e., shallow, narrow headwater sections) and subtidal (i.e., deeper and wider sections), and watersheds were delineated for each segment. In total, we report findings on 24 intertidal and 19 subtidal creeks. Indicators sampled throughout each creek included water quality (e.g., dissolved oxygen concentration, salinity, nutrients, chlorophyll-a levels), sediment quality (e.g., characteristics, contaminants levels including emerging contaminants), pathogen and viral indicators, and abundance and genetic responses of biological resources (e.g., macrobenthic and nektonic communities, shellfish tissue contaminants, oyster microarray responses). For many indicators, the intertidally-dominated or headwater portions of tidal creeks were found to respond differently than the subtidally-dominated or larger and deeper portions of tidal creeks. Study results indicate that the integrity and productivity of headwater tidal creeks were impaired by land use changes and associated non-point source pollution, suggesting these habitats are valuable early warning sentinels of ensuing ecological impacts and potential public health threats. For these headwater creeks, this research has assisted the validation of a previously developed conceptual model for the southeastern US region. This conceptual model identified adverse changes that generally occurred in the physical and chemical environment (e.g., water quality indicators such as indicator bacteria for sewage pollution or sediment chemical contamination) when impervious cover levels in the watershed reach 10-20%. Ecological characteristics responded and were generally impaired when impervious cover levels exceed 20-30%. Estimates of impervious cover levels defining where human uses are impaired are currently being determined, but it appears that shellfish bed closures and the flooding vulnerability of headwater regions become a concern when impervious cover values exceed 10-30%. This information can be used to forecast the impacts of changing land use patterns on tidal creek environmental quality as well as associated human health and well-being. In addition, this study applied tools and technologies that are adaptable, transferable, and repeatable among the high quality NERRS sites as comparable reference entities to other nearby developed coastal watersheds. The findings herein will be of value in addressing local, regional and national needs for understanding multiple stressor (anthropogenic and human impacts) effects upon estuarine ecosystems and response trends in ecosystem condition with changing coastal impacts (i.e., development, climate change). (PDF contaions 88 pages)

U.S. Caribbean fish trap fishery costs and earnings study

Executive Summary: This study describes the socio-economic characteristics of the U.S. Caribbean trap fishery that encompasses the Commonwealth of Puerto Rico and Territory of the U.S. Virgin Islands. In-person interviews were administered to one hundred randomly selected trap fishermen, constituting nearly 25% of the estimated population. The sample was stratified by geographic area and trap tier. The number of traps owned or fished to qualify for a given tier varied by island. In Puerto Rico, tier I consisted of fishermen who had between 1-40 fish traps, tier II was made up of fishermen who possessed between 41 and 100 fish traps, and tier III consisted of fishermen who held in excess of 100 fish traps. In St. Thomas and St. John, tier I was composed of fishermen who held between 1 and 50 fish traps, tier II consisted of fishermen who had between 51-150 fish traps and tier III was made up of fishermen who had in excess of 150 fish traps. Lastly, in St. Croix, tier I was made up of fishermen who had less than 20 fish traps and tier II consisted of fishermen who had 20 or more fish traps. The survey elicited information on household demographics, annual catch and revenue, trap usage, capital investment on vessels and equipment, fixed and variable costs, behavioral response to a hypothetical trap reduction program and the spatial distribution of traps. The study found that 79% of the sampled population was 40 years or older. The typical Crucian trap fisherman was older than their Puerto Rican and St. Thomian and St. Johnian counterparts. Crucian fishermen’s average age was 57 years whereas Puerto Rican fishermen’s average age was 51 years, and St. Thomian and St. Johnian fishermen’s average age was 48 years. As a group, St. Thomian and St. Johnian fishermen had 25 years of fishing experience, and Puerto Rican and Crucian fishermen had 30, and 29 years, respectively. Overall, 90% of the households had at least one dependent. The average number of dependents across islands was even, ranging between 2.8 in the district of St. Thomas and St. John and 3.4 in the district of St. Croix. The percentage utilization of catch for personal or family use was relatively low. Regionally, percentage use of catch for personal or family uses ranged from 2.5% in St. Croix to 3.8% in the St. Thomas and St. John. About 47% of the respondents had a high school degree. The majority of the respondents were highly dependent on commercial fishing for their household income. In St. Croix, commercial fishing made up 83% of the fishermen’s total household income, whereas in St. Thomas and St. John and Puerto Rico it contributed 74% and 68%, respectively. The contribution of fish traps to commercial fishing income ranged from 51% in the lowest trap tier in St. Thomas and St. John to 99% in the highest trap tier in St. Croix. On an island basis, the contribution of fish traps to fishing income was 75% in St. Croix, 61% in St. Thomas and St. John, and 59% in Puerto Rico. The value of fully rigged vessels ranged from $400 to $250,000. Over half of the fleet was worth $10,000 or less. The St. Thomas and St. John fleet reported the highest mean value, averaging $58,518. The Crucian and Puerto Rican fleets were considerably less valuable, averaging $19,831 and $8,652, respectively. The length of the vessels ranged from 14 to 40 feet. Fifty-nine percent of the sampled vessels were at least 23 feet in length. The average length of the St. Thomas and St. John fleet was 28 feet, whereas the fleets based in St. Croix and Puerto Rico averaged 21 feet. The engine’s propulsion ranged from 8 to 400 horsepower (hp). The mean engine power was 208 hp in St. Thomas and St. John, 108 hp in St. Croix, and 77 hp in Puerto Rico. Mechanical trap haulers and depth recorders were the most commonly used on-board equipment. About 55% of the sampled population reported owning mechanical trap haulers. In St. Thomas and St. John, 100% of the respondents had trap haulers compared to 52% in Puerto Rico and 20% in St. Croix. Forty-seven percent of the fishermen surveyed stated having depth recorders. Depth recorders were most common in the St. Thomas and St. John fleet (80%) and least common in the Puerto Rican fleet (37%). The limited presence of emergency position indication radio beacons (EPIRBS) and radar was the norm among the fish trap fleet. Only 8% of the respondents had EPIRBS and only 1% had radar. Interviewees stated that they fished between 1 and 350 fish traps. Puerto Rican respondents fished on average 39 fish traps, in contrast to St. Thomian and St. Johnian and Crucian respondents, who fished 94 and 27 fish traps, respectively. On average, Puerto Rican respondents fished 11 lobster traps, and St. Thomian and St. Johnian respondents fished 46 lobster traps. None of the Crucian respondents fished lobster traps. The number of fish traps built or purchased ranged between 0 and 175, and the number of lobster traps built or bought ranged between 0 and 200. Puerto Rican fishermen on average built or purchased 30 fish traps and 14 lobster traps, and St. Thomian and St. Johnian fishermen built or bought 30 fish traps and 11 lobster traps. Crucian fishermen built or bought 25 fish traps and no lobster traps. As a group, fish trap average life ranged between 1.3 and 5 years, and lobster traps lasted slightly longer, between 1.5 and 6 years. The study found that the chevron or arrowhead style was the most common trap design. Puerto Rican fishermen owned an average of 20 arrowhead traps. St. Thomian and St. Johnian and Crucian fishermen owned an average of 44 and 15 arrowhead fish traps, respectively. The second most popular trap design was the square trap style. Puerto Rican fishermen had an average of 9 square traps, whereas St. Thomian and St. Johnian fishermen had 33 traps and Crucian fishermen had 2 traps. Antillean Z (or S) -traps, rectangular and star traps were also used. Although Z (or S) -traps are considered the most productive trap design, fishermen prefer the smaller-sized arrowhead and square traps because they are easier and less expensive to build, and larger numbers of them can be safely deployed. The cost of a fish trap, complete with rope and buoys, varied significantly due to the wide range of construction materials utilized. On average, arrowhead traps commanded $94 in Puerto Rico, $251 in St. Thomas and St. John, and $119 in St. Croix. The number of trips per week ranged between 1 and 6. However, 72% of the respondents mentioned that they took two trips per week. On average, Puerto Rican fishermen took 2.1 trips per week, St. Thomian and St. Johnian fishermen took 1.4 trips per week, and Crucian fishermen took 2.5 trips per week. Most fishing trips started at dawn and finished early in the afternoon. Over 82% of the trips lasted 8 hours or less. On average, Puerto Rican fishermen hauled 27 fish traps per trip whereas St. Thomian and St. Johnian fishermen and Crucian fishermen hauled 68 and 26 fish traps per trip, respectively. The number of traps per string and soak time varied considerably across islands. In St. Croix, 84% of the respondents had a single trap per line, whereas in St. Thomas and St. John only 10% of the respondents had a single trap per line. Approximately, 43% of Puerto Rican fishermen used a single trap line. St. Thomian and St. Johnian fishermen soaked their traps for 6.9 days while Puerto Rican and Crucian fishermen soaked their traps for 5.7 and 3.6 days, respectively. The heterogeneity of the industry was also evidenced by the various economic surpluses generated. The survey illustrated that higher gross revenues did not necessarily translate into higher net revenues. Our analysis also showed that, on average, vessels in the trap fishery were able to cover their cash outlays, resulting in positive vessel income (i.e., financial profits). In Puerto Rico, annual financial profits ranged from $4,760 in the lowest trap tier to $32,467 in the highest tier, whereas in St. Thomas and St. John annual financial profits ranged from $3,744 in the lowest tier to $13,652 in the highest tier. In St. Croix, annual financial profits ranged between $9,229 and $15,781. The survey also showed that economic profits varied significantly across tiers. Economic profits measure residual income after deducting the remuneration required to keep the various factors of production in their existing employment. In Puerto Rico, annual economic profits ranged from ($9,339) in the lowest trap tier to $ 8,711 in the highest trap tier. In St. Thomas and St. John, annual economic profits ranged from ($7,920) in the highest tier to ($18,486) in the second highest tier. In St. Croix, annual economic profits ranged between ($7,453) to $10,674. The presence of positive financial profits and negative economic profits suggests that higher economic returns could be earned from a societal perspective by redirecting some of these scarce capital and human resources elsewhere in the economy. Furthermore, the presence of negative economic earnings is evidence that the fishery is overcapitalized and that steps need to be taken to ensure the long-run economic viability of the industry. The presence of positive financial returns provides managers with a window of opportunity to adopt policies that will strengthen the biological and economic performance of the fishery while minimizing any adverse impacts on local fishing communities. Finally, the document concludes by detailing how the costs and earnings information could be used to develop economic models that evaluate management proposals. (PDF contains 147 pages)

Fish sorting assessments of Clarias gariepinus fingerlings raised in fish tanks

Fish sorting assessments of Clarias gariepinus fingerlings stocked and raised in fish tanks were undertaken for a 6-month culture period: Sorting was undertaken from the first, second, and third months of stocking the fish fingerlings while the control was not sorted at all. The sorting assessments revealed that the twice sorting of fish fingerlings stocked with a Marginal Rate of Return (MRR) of 3.44 was significantly different (p>0.05) from those sorted once with MRR of 0.912, and three times with MRR of 2.65 respectively, thus making twice sorting most advisable for fish farmers utilizing Clarias gariepinus fingerlings for tank aquaculture

Improving reporting of uncertainties in sea level rise assessments

Sea level rise (SLR) assessments are commonly used to identify the extent that coastal populations are at risk to flooding. However, the data and assumptions used to develop these assessments contain numerous sources and types of uncertainty, which limit confidence in the accuracy of modeled results. This study illustrates how the intersection of uncertainty in digital elevation models (DEMs) and SLR lead to a wide range of modeled outcomes. SLR assessments are then reviewed to identify the extent that uncertainty is documented in peer-reviewed articles. The paper concludes by discussing priorities needed to further understand SLR impacts. (PDF contains 4 pages)

Assessing the quality of water quality assessments: An analytical quality control protocol for benthic diatoms

In this paper, the background to the development of an analytical quality control procedure for the Trophic Diatom Index (TDI) is explained, highlighting some of the statistical and taxonomic problems encountered, and going on to demonstrate how the system works in practice. Most diatom-based pollution indices, including the TDI, use changes in the relative proportions of different taxa to indicate changing environmental conditions. The techniques involved are therefore much simpler than those involved in many studies of phytoplankton, for example, where absolute numbers are required.

Blue frontiers: managing the environmental costs of aquaculture

The report begins with an overview of the current status of world aquaculture. It then goes on to describe an approach for estimating the current combined biophysical resource demands of aquaculture for producer countries and regions. Following a comparison of these results with those available for other animal food production sectors the report then examines the consequences of likely future trends in production on the environmental impacts of aquaculture. Finally, the policy implications of the report’s findings are discussed along with the research agenda that should be pursued to meet the challenge of sustainable food production.

A meta-analytic approach to quantifying scientific uncertainty in stock assessments

Quantifying scientific uncertainty when setting total allowable catch limits for fish stocks is a major challenge, but it is a requirement in the United States since changes to national fisheries legislation. Multiple sources of error are readily identifiable, including estimation error, model specification error, forecast error, and errors associated with the definition and estimation of reference points. Our focus here, however, is to quantify the influence of estimation error and model specification error on assessment outcomes. These are fundamental sources of uncertainty in developing scientific advice concerning appropriate catch levels and although a study of these two factors may not be inclusive, it is feasible with available information. For data-rich stock assessments conducted on the U.S. west coast we report approximate coefficients of variation in terminal biomass estimates from assessments based on inversion of the assessment of the model’s Hessian matrix (i.e., the asymptotic standard error). To summarize variation “among” stock assessments, as a proxy for model specification error, we characterize variation among multiple historical assessments of the same stock. Results indicate that for 17 groundfish and coastal pelagic species, the mean coefficient of variation of terminal biomass is 18%. In contrast, the coefficient of variation ascribable to model specification error (i.e., pooled among-assessment variation) is 37%. We show that if a precautionary probability of overfishing equal to 0.40 is adopted by managers, and only model specification error is considered, a 9% reduction in the overfishing catch level is indicated.

Use of genetic data to assess the uncertainty in stock assessments due to the assumed stock structure: the case of albacore (Thunnus alalunga) from the Atlantic Ocean

Stock assessments can be problematic because of uncertainties associated with the data or because of simplified assumptions made when modeling biological processes (Rosenberg and Restrepo, 1995). For example, the common assumption in stock assessments that stocks are homogeneous and discrete (i.e., there is no migration between the stocks) is not necessarily true (Kell et al., 2004a, 2004b).

Fisheries co-management and transaction costs

Fisheries co-management is increasingly seen as a solution to the problems of resource use conflicts and overexploitation. The importance of transactions costs may not have been given adequate attention. The transaction costs are 1) information costs, 2) collective decisionmaking tools, and 3) collective operational costs. The various components of transaction costs of fisheries co-management systems are described in this paper. These costs need to be determined for evaluating the feasibility of a co-managed fishery compared to a centrally managed one.

Reducing feed costs in semi-intensive finfish culture: an update on mixed feeding schedules and an idea for enhancing endogenous food supply in ponds

Some interesting ideas on improving the cost-effectiveness of feeding in semi-intensive finfish aquaculture are presented.

Measuring transaction costs of fisheries co-management in San Salvador Island, Philippines

It is generally accepted that co-management systems are more cost-effective than centralized management of natural resources. However, no attempts have been made to empirically verify the transaction costs involved in fisheries co-management. Some estimates of transaction costs of fisheries co-management in San Salvador Island, Philippines, are presented in this paper. These estimates are used to compare the various transaction costs in co-managed and in centrally managed fisheries in San Salvador Island.

Reported Trip Costs, Gross Revenues, and Net Returns for U.S. Atlantic Pelagic Longline Vessels

Logbook set and trip summary data (containing catch and cost information, respectively) collected by NOAA’s National Marine Fisheries Service (NMFS) were analyzed for U.S. pelagic longline vessels that participated in Atlantic fisheries in 1996. These data were augmented with vessel information from the U.S. Coast Guard. Mean fish weights and ex-vessel prices from NMFS observers and licensed seafood dealers, respectively, were used to estimate gross revenues. Comparisons revealed that net returns varied substantially by vessel size and fishing behavior (i.e. sets per trip, fishing location, season, and swordfish targeting). While the calculated economic effects of proposed regulations will depend on the descriptive statistic chosen for analysis, which itself depends on the type of analysis being conducted, results show that considering heterogeneity within this fleet can have a significant effect on predicted economic consequences.

Habitats regulations for stage 3 assessments radioactive substance authorisations

This is the Habitats regulations for stage 3 assessments: radioactive substances authorisations report from the Environment Agency, published on October 2003. The report focuses on the stage 3 assessments of radioactive substances authorisations in UK (to take place over the next five years, starting in 2003), which may have a potential impact on European designated Natura 2000 sites such Special Protection Areas (SPA), Special Areas of Conservation (SAC); and thus require further detailed assessment. This Environment Agency R&D project was commissioned to ERC, University o f Liverpool, in conjunction with Westlakes Scientific Consulting and the Centre for Ecology and Hydrology, as part o f the agency's preparation for the Stage 3 Assessments o f radioactive substances authorisations. The aim was to prepare site information sheets containing all data relevant for individual Natura 2000 sites needing Stage 3 Assessment and to stylise and represent species that require protection under the Habitats Regulations by the reference organism geometries listed in R&D Publication 128 (Copplestone et al., 2001).