Patterns of scale-dependency and the influence of map resolution on the seascape ecology of reef fish

Detection and perception of ecological relationships between biota and their surrounding habitats is sensitive to analysis scale and resolution of habitat data. We measured strength of univariate linear correlations between reef fish and seascape variables at multiple spatial scales (25 to 800 m). Correlation strength was used to identify the scale that best associates fish to their surrounding habitat. To evaluate the influence of map resolution, seascape variables were calculated based on 4 separate benthic maps produced using 2 levels of spatial and thematic resolution, respectively. Individual seascape variables explained only 25% of the variability in fish distributions. Length of reef edge was correlated with more aspects of the fish assemblage than other features. Area of seagrass and bare sand correlated with distribution of many fish, not just obligate users. No fish variables correlated with habitat diversity. Individual fish species achieved a wider range of correlations than mobility guilds or the entire fish assemblage. Scales of peak correlation were the same for juveniles and adults in a majority of comparisons. Highly mobile species exhibited broader scales of peak correlation than either resident or moderately mobile fish. Use of different input maps changed perception of the strength and even the scale of peak correlations for many comparisons involving hard bottom edge length and area of sand, whereas results were consistent regardless of map type for comparisons involving area of seagrass and habitat diversity.

The coupling of St. John, US Virgin Islands Marine Protected Areas based on reef fish habitat affinities and movements across management boundaries [Poster]

NOAA's Biogeograpy Branch, the National Park Service (NPS), US Geological Survey, and the University of the Virgin Islands (UVI) are using acoustice telemetry to quantify spatial patterns and habitat affinities of reef fishes in the US Virgin Islands (USVI). The objective of the study is to define the movements of reef fishes among habitats within and between the Virgin Islands Coral Reef Nationla Monument (VICRNM), adjacent to Virgin Islands National Park (VIIS), and USVI Territorial waters. In order to better understand species habitat utilization patterns and movement of fishes among management regimes and areas open to fishing around St. John, we deployed an array of hydroacoutstic receivers and acoustically tagged reef fishes. A total of 150 fishes, representing 18 species and 10 families were acoustically tagged along the south shore of St. John from July 2006 to June 2008. Thirty six receivers with a detection range of approximately 300m each were deployed in shallow nearshore bays and across the shelf to depths of approximately 30m. Receivers were located within reefs and adjacent to reefs in seagrass, algal beds, or sand habitats. Example results include the movement of lane snappers and blue striped grunts that demonstrated diel movement from reef habitats during daytime hours to offshore seagrass beds at night. Fish associated with reefs that did not have adjacent seagrass beds made more extensive movements than those fishes associated with reefs that had adjacent seagrass habitats. The array comprised of both nearshore and cross shelf location of receives provides information on fine to broad scale fish movement patterns across habitats and among management units to examine the strength of ecological connectivity between management areas and habitats. For more information go to: http://ccma.nos.noaa.gov/ecosystems/ coralreef/acoustic_tracking.html

Assessing the impacts of experimental derelict fish traps in the U.S. Virgin Islands [Poster]

Fish traps are commonly used throughout the Caribbean to catch reef fish species and lobster and are the primary gear of choice for fishermen in the U.S. Virgin Islands. Once they are lost or abandoned they are referred to as derelict fish traps (DFTs)and a widespread concern exists that they contribute to ghostfishing. Ghostfishing occurs when derelict fishing gear continues to catch fish and induce mortality. Despite the public concerns that DFTs are an environmental threat, few studies have quantified the level of ghostfishing in the Caribbean. To address concerns from the fishing community and other marine stakeholders, this study provides the first experimental examination of ghostfishing impacts to fish and the potential economic impacts to fisheries in the U.S. Virgin Islands.

Assessment of existing information on Atlantic coastal fish habitats: development of a web-based spatial bibliography, query tools, and data summaries

The primary objective of this project, “the Assessment of Existing Information on Atlantic Coastal Fish Habitat”, is to inform conservation planning for the Atlantic Coastal Fish Habitat Partnership (ACFHP). ACFHP is recognized as a Partnership by the National Fish Habitat Action Plan (NFHAP), whose overall mission is to protect, restore, and enhance the nation’s fish and aquatic communities through partnerships that foster fish habitat conservation. This project is a cooperative effort of NOAA/NOS Center for Coastal Monitoring and Assessment (CCMA) Biogeography Branch and ACFHP. The Assessment includes three components; 1. a representative bibliographic and assessment database, 2. a Geographical Information System (GIS) spatial framework, and 3. a summary document with description of methods, analyses of habitat assessment information, and recommendations for further work. The spatial bibliography was created by linking the bibliographic table developed in Microsoft Excel and exported to SQL Server, with the spatial framework developed in ArcGIS and exported to GoogleMaps. The bibliography is a comprehensive, searchable database of over 500 selected documents and data sources on Atlantic coastal fish species and habitats. Key information captured for each entry includes basic bibliographic data, spatial footprint (e.g. waterbody or watershed), species and habitats covered, and electronic availability. Information on habitat condition indicators, threats, and conservation recommendations are extracted from each entry and recorded in a separate linked table. The spatial framework is a functional digital map based on polygon layers of watersheds, estuarine and marine waterbodies derived from NOAA’s Coastal Assessment Framework, MMS/NOAA’s Multipurpose Marine Cadastre, and other sources, providing spatial reference for all of the documents cited in the bibliography. Together, the bibliography and assessment tables and their spatial framework provide a powerful tool to query and assess available information through a publicly available web interface. They were designed to support the development of priorities for ACFHP’s conservation efforts within a geographic area extending from Maine to Florida, and from coastal watersheds seaward to the edge of the continental shelf. The Atlantic Coastal Fish Habitat Partnership has made initial use of the Assessment of Existing Information. Though it has not yet applied the AEI in a systematic or structured manner, it expects to find further uses as the draft conservation strategic plan is refined, and as regional action plans are developed. It also provides a means to move beyond an “assessment of existing information” towards an “assessment of fish habitat”, and is being applied towards the National Fish Habitat Action Plan (NFHAP) 2010 Assessment. Beyond the scope of the current project, there may be application to broader initiatives such as Integrated Ecosystem Assessments (IEAs), Ecosystem Based Management (EBM), and Marine Spatial Planning (MSP).

Mesoscale, cyclonic eddies as larval fish habitat along the southeast United States shelf: A Lagrangian description of the zooplankton community

The Charleston Gyre region is characterized by continuous series of cyclonic eddies that propagate northeastwards before decaying or coalescing with the Gulf Stream south of Cape Hatteras, NC, USA. Over 5 d, chlorophyll-a concentration, zooplankton displacement volume, and zooplankton composition and abundance changed as the eddy moved to the northeast. Surface chlorophyll-a concentration decreased, and zooplankton displacement remained unchanged as the eddy propagated. Zooplankton taxa known to be important dietary constituents of larval fish increased in concentration as the eddy propagated. The concurrent decrease in chlorophyll-a concentration and static zooplankton displacement volume can be explained by initial stimulation of chlorophyll-a concentration by upwelling and nutrient enrichment near the eddy core and to possible grazing as zooplankton with short generation times and large clutch sizes increased in concentration. The zooplankton community did not change significantly within the 5 d that the eddy was tracked, and there was no indication of succession. Mesoscale eddies of the region are dynamic habitats as eddies propagate northeastwards at varying speeds within monthly periods. The abundance of zooplankton important to the diets of larval fish indicates that the region can provide important pelagic nursery habitat for larval fish off the southeast coast of the United States. A month of feeding and growth is more than half the larval duration of most fish spawned over the continental shelf of the southeastern United States in winter.

An ecological characterization of the marine resources of Vieques, Puerto Rico Part II: Field studies of habitats, nutrients, contaminants, fish, and benthic communities

Since the 1940s, portions of the Island of Vieques, Puerto Rico have been used by the United States Navy (USN) as an ammunition support detachment and bombing and maneuver training range. In April 2001, the USN began phasing out military activities on the island and transferring military property to the U.S. Department of the Interior, the Municipality of Vieques, and the Puerto Rico Conservation Trust. A small number of studies have been commissioned by the USN in the past few decades to assess selected components of the coral reef ecosystem surrounding the island; however, these studies were generally of limited geographic scope and short duration. The National Oceanic and Atmospheric Administration’s (NOAA) National Centers for Coastal Ocean Science (NCCOS), in consultation with NOAA’s Office of Response and Restoration (OR&R) and other local and regional experts, conducted a more comprehensive characterization of coral reef ecosystems, contaminants, and nutrient distribution patterns around Vieques. This work was conducted using many of the same protocols as ongoing monitoring work underway elsewhere in the U.S. Caribbean and has enabled comparisons among coral reef ecosystems in Vieques and other locations in the region. This characterization of Vieques’ marine ecosystems consists of a two part series. First, available information on reefs, fish, birds, seagrasses, turtles, mangroves, climate, geology, currents, and human uses from previous studies was gathered and integrated into a single document comprising Part I of this two part series (Bauer et al. 2008). For Part II of the series, presented in this document, new field studies were conducted to fill data gaps identified in previous studies, to provide an island-wide characterization, and to establish baseline values for the distribution of habitats, nutrients, contaminants, fish, and benthic communities. An important objective underlying this suite of studies was to quantify any differences in the marine areas adjacent to the former and current land-use zoning around Vieques. Specifically of interest was the possibility that either Naval (e.g., practice bombing, munitions storage) or civilian activities (e.g., sewage pollutants, overfishing) could have a negative impact on adjacent marine resources. Measuring conditions at this time and so recently after the land transfer was essential because present conditions are likely to be reflective of past land-use practices. In addition, the assessment will establish benchmark conditions that can be influenced by the potentially dramatic future changes in land-use practices as Vieques considers its development. This report is organized into seven chapters that represent a suite of interrelated studies. Chapter 1 provides a short introduction to the island setting, the former and current land-use zoning, and how the land zoning was used to spatially stratify much of the sampling. Chapter 2 is focused on benthic mapping and provides the methods, accuracy assessment, and results of newly created benthic maps for Vieques. Chapter 3 presents the results of new surveys of fish, marine debris, and reef communities on hardbottom habitats around the island. Chapter 4 presents results of flora and fauna surveys in selected bays and lagoons. Chapter 5 examines the distribution of nutrients in lagoons, inshore, and offshore waters around the island. Chapter 6 is focused on the distribution of chemical contaminants in sediments and corals. Chapter 7 is a brief summary discussion that highlights key findings of the entire suite of studies.

Coral reef ecosystems of Reserva Natural de La Parguera (Puerto Rico): spatial and temporal patterns in fish and benthic communities (2001-2007)

Since 1999, NOAA’s Center for Coastal Monitoring and Assessment, Biogeography Branch (CCMA-BB) has been working with federal and territorial partners to characterize monitor and assess the status of the marine environment in southwestern Puerto Rico. This effort is part of the broader NOAA Coral Reef Conservation Program’s (CRCP) National Coral Reef Ecosystem Monitoring Program (NCREMP). With support from CRCP’s NCREMP, CCMA conducts the “Caribbean Coral Reef Ecosystem Monitoring project” (CREM) with goals to: (1) spatially characterize and monitor the distribution, abundance and size of marine fauna associated with shallow water coral reef seascapes (mosaics of coral reefs, seagrasses, sand and mangroves); (2) relate this information to in situ fine-scale habitat data and the spatial distribution and diversity of habitat types using benthic habitat maps; (3) use this information to establish the knowledge base necessary for enacting management decisions in a spatial setting; (4) establish the efficacy of those management decisions; and (5) develop data collection and data management protocols. The monitoring effort of the La Parguera region in southwestern Puerto Rico was conducted through partnerships with the University of Puerto Rico (UPR) and the Puerto Rico Department of Natural and Environmental Resources (DNER). Project funding was primarily provided by NOAA CRCP and CCMA. In recent decades, scientific and non-scientific observations have indicated that the structure and function of the coral reef ecosystem in the La Parguera region have been adversely impacted by a wide range of environmental stressors. The major stressors have included the mass Diadema die off in the early 1980s, a suite of hurricanes, overfishing, mass mortality of Acropora corals due to disease and several coral bleaching events, with the most severe mass bleaching episode in 2005. The area is also an important recreational resource supporting boating, snorkeling, diving and other water based activities. With so many potential threats to the marine ecosystem several activities are underway or have been implemented to manage the marine resources. These efforts have been supported by the CREM project by identifying marine fauna and their spatial distributions and temporal dynamics. This provides ecologically meaningful data to assess ecosystem condition, support decision making in spatial planning (including the evaluation of efficacy of current management strategies) and determine future information needs. The ultimate goal of the work is to better understand the coral reef ecosystems and to provide information toward protecting and enhancing coral reef ecosystems for the benefit of the system itself and to sustain the many goods and services that it offers society. This Technical Memorandum contains analysis of the first seven years of fish survey data (2001-2007) and associated characterization of the benthos. The primary objectives were to quantify changes in fish species and assemblage diversity, abundance, biomass and size structure and to provide spatially explicit information on the distribution of key species or groups of species and to compare community structure across the seascape including fringing mangroves, inner, middle, and outer reef areas, and open ocean shelf bank areas.

Analyzing and mapping fish assemblages off central California, USA

This study describes fish assemblages and their spatial patterns off the coast of California from Point Arena to Point Sal, by combining the results of the multivariate analyses of several fisheries datasets with a geographic information system. In order to provide comprehensive spatial coverage for the areas of inshore, continental shelf, and continental slope, three fisheries datasets were analyzed: 1) Inshore: the California Department of Fish and Game dataset of fishery-dependent commercial passenger fishing vessel trips that targeted rockfish; 2) Continental Shelf: the National Marine Fisheries Service (NMFS) fishery-independent bottom trawls; and 3) Continental Slope: the NMFS fishery-independent bottom trawls on the continental slope. One-hundred seven species were analyzed. These species represented those captured in at least 5% of the fishing trips or trawls in at least one of the three data sets. We analyzed each of the three datasets separately, and the three sets of results were combined to define 28 species assemblages and 23 site groups. A species assemblage consisted of species caught together, whereas a site group consisted of fishing trips or trawl locations that tended to have the same species assemblages. At the scale of these datasets, 97% of all site groups were significantly segregated by depth.

Biogeographic characterization of essential fish habitats affected by human activities in the coastal zone of Puerto Rico

The overall purpose of this project was to collect available information on the characteristics of essential fish habitats in protected and non-protected marine areas around the islands of Puerto Rico. Specifically, this project compiled historical information on benthic habitats and the status of marine resources into a Geographic Information System (GIS) by digitizing paper copies of existing marine geologic maps that were developed for the Caribbean Fishery Management Council (CFMC) for areas around the Commonwealth of Puerto Rico. In addition, information on benthic habitat types, Essential Fish Habitat (EFH) requirements, and fishing and non-fishing impacts to marine resources were compiled for two priority areas: La Parguera and Vieques. The information obtained will help to characterize and select habitats for future monitoring of impacts of fishing and non-fishing activities and to develop management recommendations for conservation of important marine habitats. The project focused specifically on areas identified as priorities for conservation by the Puerto Rico Department of Natural and Environmental Resources (DNER) and the Local Action Strategy Overfishing Group.

Fatty acid composition of red drum maintained by fishmeal, fish oil substitutes in diets

Recent research by the authors evaluated strategies to reduce fishmeal and fish oil in diets for red drum by substituting terrestrial proteins and lipids while maintaining beneficial fatty acids with DHA supplements derived from marine algae. Results suggested fatty acid-enriched finishing diets can be used with growout diets containing little or no fishmeal and fish oil to achieve the desired DHA content in the final fish fillets.

Long-term monitoring of habitats and reef fish found inside and outside the U.S. Virgin Islands Coral Reef National Monument: a comparative assessment

The primary objective of this study was to assess the efficacy of the Virgin Islands Coral Reef National Monument (VICR), a marine protected area in St John, US Virgin Islands. Surveys of habitat and fishes inside and outside of VICR were conducted in 2003-2008. Areas outside the VICR had significantly more scleractinian corals, greater habitat complexity, and greater species richness and density of reef fishes than areas inside., Areas inside and outside the VICR exhibited significant decreases in percent scleractinian coral coverage over the study period. A contrasting trend of increasing macroalgal cover was also observed. No clear effect of the severe 2005 coral bleaching event was observed suggesting other causal factors. No obvious trends in the fish community were observed across the study period. The significant decline in habitat condition, coupled with the initial incorporation of some of the more degraded reefs into the marine protected area may result in a longer time period necessary to detect positive changes in the St. John coral reef ecosystem and associated reef fish abundance and community structure.

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.

Cruise report: summer 2009 Sapelo Island National Estuarine Research Reserve ecological characterization (June 7 - June 13, 2009)

This cruise report is a summary of a field survey conducted within the Sapelo Island National Estuarine Research Reserve (SINERR), located on the Georgia coastline, June 7 – June 13, 2009. Multiple indicators of ecological condition and human dimensions were sampled synoptically at each of 30 stations throughout SINERR using a random probabilistic sampling design. Samples were collected for the analysis of benthic community structure and composition; concentrations of chemical contaminants (metals, pesticides, PAHs, PCBs, PBDEs) in sediments and target demersal biota; nutrient and chlorophyll levels in the water column; bacterial contaminants in the water column; and other basic habitat characteristics such as depth, salinity, temperature, dissolved oxygen, turbidity, total suspended solids, pH, sediment grain size, and organic carbon content. In addition to the fish samples that were collected for analysis of chemical contaminants relative to human-health consumption limits, other human-dimension indicators were sampled as well including presence or absence of fishing gear, vessels, surface trash, and noxious sediment odors. The overall purpose of the survey was to collect data to assess the status of ecosystem condition and potential stressor impacts throughout SINERR, based on these various indicators and corresponding management thresholds, and to provide this information as a baseline for determining how such conditions may be changing with time. While sample analysis is still ongoing a few preliminary results and observations are reported here. A final report will be completed once all data have been processed. The results will provide a comprehensive weight-of-evidence basis for evaluating current condition (aka a “state-of-the-SINEER environmental report”) and serve as a quantitative benchmark for tracking any future changes due to either natural or human disturbances. Another goal of the study is to demonstrate its utility as a possible model for assessing the status of condition at other NEERS sites using similar and consistent methods to promote system-wide regional and national comparisons.

Biogeographic characterization of fish communities and associated benthic habitats within the Flower Garden Banks National Marine Sanctuary: sampling design and implementation of scuba surveys on the coral caps

The Flower Garden Banks National Marine Sanctuary (FGBNMS) is located in the northwestern Gulf of Mexico approximately 180 km south of Galveston, Texas. The sanctuary’s distance from shore combined with its depth (the coral caps reach to within approximately 17 m of the surface) result in limited exposure of this coral reef ecosystem to natural and human-induced impacts compared to other coral reefs of the western Atlantic. In spite of this, the sanctuary still confronts serious impacts including hurricanes events, recent outbreaks of coral disease, an increase in the frequency of coral bleaching and the massive Diadema antillarum die-off during the mid-1980s. Anthropogenic impacts include large vessel anchoring, commercial and recreational fishing, recreational scuba diving, and oil and gas related activities. The FGBNMS was designated in 1992 to help protect against some of these impacts. Basic monitoring and research efforts have been conducted on the banks since the 1970s. Early on, these efforts focused primarily on describing the benthic communities (corals, sponges) and providing qualitative characterizations of the fish community. Subsequently, more quantitative work has been conducted; however, it has been limited in spatial scope. To complement these efforts, the current study addresses the following two goals put forth by sanctuary management: 1) to develop a sampling design for monitoring benthic fish communities across the coral caps; and 2) to obtain a spatial and quantitative characterization of those communities and their associated habitats.

Nocturnal fish movement and trophic flow across habitat boundaries in a coral reef ecosystem (SW Puerto Rico)

Few studies have quantified the extent of nocturnal cross-habitat movements for fish, or the influence of habitat adjacencies on nutrient flows and trophodynamics. To investigate the patterns of nocturnal cross-boundary movements of fish and quantify trophic connectivity, fish were sampled at night with gillnets set along the boundaries between dominant habitat types (coral reef/seagrass and mangrove/seagrass) in southwestern Puerto Rico. Fish movement across adjacent boundary patches were equivalent at both coral reefs and mangroves. Prey biomass transfer was greater from seagrass to coral reefs (0.016 kg/km) and from mangroves to seagrass (0.006 kg/km) but not statistically significant, indicating a balance of flow between adjacent habitats. Pelagic species (jacks, sharks, rays) accounted for 37% of prey biomass transport at coral reef/seagrass and 46% at mangrove/seagrass while grunts and snappers accounted for 7% and 15%, respectively. This study indicated that coral reefs and mangroves serve as a feeding area for a wide range of multi-habitat fish species. Crabs were the most frequent prey item in fish leaving coral reefs while molluscs were observed slightly more frequently than crabs in fish entering coral reefs. For most prey types, biomass exported from mangroves was greater than biomass imported. The information on direction of fish movement together with analysis of prey data provided strong evidence of ecological linkages between distinct adjacent habitat types and highlighted the need for greater inclusion of a mosaic of multiple habitats when attempting to understand ecosystem function including the spatial transfer of energy across the seascape.